Merge trunk

40 files changed, 3570 insertions, 1983 deletions

diff --git a/generic/tcl.h b/generic/tcl.h
index ab54078..b93b3ac 100644
--- a/generic/tcl.h
+++ b/generic/tcl.h
@@ -67,15 +67,12 @@ extern "C" {
  * We use this method because there is no autoconf equivalent.
  */
 
-#ifndef __WIN32__
-#   if defined(_WIN32) || defined(WIN32) || defined(__MINGW32__) || defined(__BORLANDC__) || (defined(__WATCOMC__) && defined(__WINDOWS_386__))
+#ifdef _WIN32
+#   ifndef __WIN32__
 #	define __WIN32__
-#	ifndef WIN32
-#	    define WIN32
-#	endif
-#	ifndef _WIN32
-#	    define _WIN32
-#	endif
+#   endif
+#   ifndef WIN32
+#	define WIN32
 #   endif
 #endif
 
@@ -83,11 +80,11 @@ extern "C" {
  * STRICT: See MSDN Article Q83456
  */
 
-#ifdef __WIN32__
+#ifdef _WIN32
 #   ifndef STRICT
 #	define STRICT
 #   endif
-#endif /* __WIN32__ */
+#endif /* _WIN32 */
 
 /*
  * Utility macros: STRINGIFY takes an argument and wraps it in "" (double
@@ -191,7 +188,7 @@ extern "C" {
  *       MSVCRT.
  */
 
-#if (defined(__WIN32__) && (defined(_MSC_VER) || (__BORLANDC__ >= 0x0550) || defined(__LCC__) || defined(__WATCOMC__) || (defined(__GNUC__) && defined(__declspec))))
+#if (defined(_WIN32) && (defined(_MSC_VER) || (defined(__BORLANDC__) && (__BORLANDC__ >= 0x0550)) || defined(__LCC__) || defined(__WATCOMC__) || (defined(__GNUC__) && defined(__declspec))))
 #   define HAVE_DECLSPEC 1
 #   ifdef STATIC_BUILD
 #       define DLLIMPORT
@@ -315,14 +312,14 @@ extern "C" {
  * VOID. This block is skipped under Cygwin and Mingw.
  */
 
-#if defined(__WIN32__) && !defined(HAVE_WINNT_IGNORE_VOID)
+#if defined(_WIN32) && !defined(HAVE_WINNT_IGNORE_VOID)
 #ifndef VOID
 #define VOID void
 typedef char CHAR;
 typedef short SHORT;
 typedef long LONG;
 #endif
-#endif /* __WIN32__ && !HAVE_WINNT_IGNORE_VOID */
+#endif /* _WIN32 && !HAVE_WINNT_IGNORE_VOID */
 
 /*
  * Macro to use instead of "void" for arguments that must have type "void *"
@@ -390,7 +387,7 @@ typedef long LONG;
  */
 
 #if !defined(TCL_WIDE_INT_TYPE)&&!defined(TCL_WIDE_INT_IS_LONG)
-#   if defined(__WIN32__)
+#   if defined(_WIN32)
 #      define TCL_WIDE_INT_TYPE __int64
 #      ifdef __BORLANDC__
 #         define TCL_LL_MODIFIER	"L"
@@ -400,7 +397,7 @@ typedef long LONG;
 #   elif defined(__GNUC__)
 #      define TCL_WIDE_INT_TYPE long long
 #      define TCL_LL_MODIFIER	"ll"
-#   else /* ! __WIN32__ && ! __GNUC__ */
+#   else /* ! _WIN32 && ! __GNUC__ */
 /*
  * Don't know what platform it is and configure hasn't discovered what is
  * going on for us. Try to guess...
@@ -415,7 +412,7 @@ typedef long LONG;
 #	     define TCL_WIDE_INT_TYPE long long
 #         endif
 #      endif /* NO_LIMITS_H */
-#   endif /* __WIN32__ */
+#   endif /* _WIN32 */
 #endif /* !TCL_WIDE_INT_TYPE & !TCL_WIDE_INT_IS_LONG */
 #ifdef TCL_WIDE_INT_IS_LONG
 #   undef TCL_WIDE_INT_TYPE
@@ -447,7 +444,7 @@ typedef unsigned TCL_WIDE_INT_TYPE	Tcl_WideUInt;
 #   define Tcl_DoubleAsWide(val)	((Tcl_WideInt)((double)(val)))
 #endif /* TCL_WIDE_INT_IS_LONG */
 
-#if defined(__WIN32__)
+#if defined(_WIN32)
 #   ifdef __BORLANDC__
 	typedef struct stati64 Tcl_StatBuf;
 #   elif defined(_WIN64)
@@ -458,7 +455,7 @@ typedef unsigned TCL_WIDE_INT_TYPE	Tcl_WideUInt;
 	typedef struct _stat32i64 Tcl_StatBuf;
 #   endif /* _MSC_VER < 1400 */
 #elif defined(__CYGWIN__)
-    typedef struct _stat32i64 {
+    typedef struct {
 	dev_t st_dev;
 	unsigned short st_ino;
 	unsigned short st_mode;
@@ -562,7 +559,7 @@ typedef struct Tcl_ZLibStream_ *Tcl_ZlibStream;
  * will be called as the main fuction of the new thread created by that call.
  */
 
-#if defined __WIN32__
+#if defined _WIN32
 typedef unsigned (__stdcall Tcl_ThreadCreateProc) (ClientData clientData);
 #else
 typedef void (Tcl_ThreadCreateProc) (ClientData clientData);
@@ -574,7 +571,7 @@ typedef void (Tcl_ThreadCreateProc) (ClientData clientData);
  * in generic/tclThreadTest.c for it's usage.
  */
 
-#if defined __WIN32__
+#if defined _WIN32
 #   define Tcl_ThreadCreateType		unsigned __stdcall
 #   define TCL_THREAD_CREATE_RETURN	return 0
 #else
diff --git a/generic/tclAssembly.c b/generic/tclAssembly.c
index fc51457..d1866c8 100644
--- a/generic/tclAssembly.c
+++ b/generic/tclAssembly.c
@@ -26,6 +26,7 @@
  *-   jumpTable testing
  *-   syntax (?)
  *-   returnCodeBranch
+ *-   tclooNext, tclooNextClass
  */
 
 #include "tclInt.h"
@@ -49,7 +50,7 @@ typedef enum BasicBlockCatchState {
     BBCS_UNKNOWN = 0,		/* Catch context has not yet been identified */
     BBCS_NONE,			/* Block is outside of any catch */
     BBCS_INCATCH,		/* Block is within a catch context */
-    BBCS_CAUGHT,		/* Block is within a catch context and
+    BBCS_CAUGHT 		/* Block is within a catch context and
 				 * may be executed after an exception fires */
 } BasicBlockCatchState;
 
@@ -120,7 +121,7 @@ enum BasicBlockFlags {
 				 * marking it as the start of a 'catch'
 				 * sequence. The 'jumpTarget' is the exception
 				 * exit from the catch block. */
-    BB_ENDCATCH = (1 << 5),	/* Block ends with an 'endCatch' instruction,
+    BB_ENDCATCH = (1 << 5)	/* Block ends with an 'endCatch' instruction,
 				 * unwinding the catch from the exception
 				 * stack. */
 };
@@ -183,7 +184,7 @@ typedef enum TalInstType {
 				 * produces N */
     ASSEM_SINT1,		/* One 1-byte signed-integer operand
 				 * (INCR_STK_IMM) */
-    ASSEM_SINT4_LVT4,		/* Signed 4-byte integer operand followed by
+    ASSEM_SINT4_LVT4		/* Signed 4-byte integer operand followed by
 				 * LVT entry.  Fixed arity */
 } TalInstType;
 
@@ -246,8 +247,6 @@ static void		BBEmitInstInt4(AssemblyEnv* assemEnvPtr, int tblIdx,
 			    int opnd, int count);
 static void		BBEmitInst1or4(AssemblyEnv* assemEnvPtr, int tblIdx,
 			    int param, int count);
-static void		BBEmitInvoke1or4(AssemblyEnv* assemEnvPtr, int tblIdx,
-			    int param, int count);
 static void		BBEmitOpcode(AssemblyEnv* assemEnvPtr, int tblIdx,
 			    int count);
 static int		BuildExceptionRanges(AssemblyEnv* assemEnvPtr);
@@ -351,7 +350,8 @@ static const TalInstDesc TalInstructionTable[] = {
     {"bitnot",		ASSEM_1BYTE,	INST_BITNOT,		1,	1},
     {"bitor",		ASSEM_1BYTE,	INST_BITOR,		2,	1},
     {"bitxor",		ASSEM_1BYTE,	INST_BITXOR,		2,	1},
-    {"concat",		ASSEM_CONCAT1,	INST_CONCAT1,		INT_MIN,1},
+    {"concat",		ASSEM_CONCAT1,	INST_STR_CONCAT1,	INT_MIN,1},
+    {"concatStk",	ASSEM_LIST,	INST_CONCAT_STK,	INT_MIN,1},
     {"coroName",	ASSEM_1BYTE,	INST_COROUTINE_NAME,	0,	1},
     {"currentNamespace",ASSEM_1BYTE,	INST_NS_CURRENT,	0,	1},
     {"dictAppend",	ASSEM_LVT4,	INST_DICT_APPEND,	2,	1},
@@ -438,6 +438,8 @@ static const TalInstDesc TalInstructionTable[] = {
     {"nop",		ASSEM_1BYTE,	INST_NOP,		0,	0},
     {"not",		ASSEM_1BYTE,	INST_LNOT,		1,	1},
     {"nsupvar",		ASSEM_LVT4,	INST_NSUPVAR,		2,	1},
+    {"numericType",	ASSEM_1BYTE,	INST_NUM_TYPE,		1,	1},
+    {"originCmd",	ASSEM_1BYTE,	INST_ORIGIN_COMMAND,	1,	1},
     {"over",		ASSEM_OVER,	INST_OVER,		INT_MIN,-1-1},
     {"pop",		ASSEM_1BYTE,	INST_POP,		1,	0},
     {"pushReturnCode",	ASSEM_1BYTE,	INST_PUSH_RETURN_CODE,	0,	1},
@@ -454,7 +456,11 @@ static const TalInstDesc TalInstructionTable[] = {
 					 | INST_STORE_ARRAY4),	2,	1},
     {"storeArrayStk",	ASSEM_1BYTE,	INST_STORE_ARRAY_STK,	3,	1},
     {"storeStk",	ASSEM_1BYTE,	INST_STORE_STK,		2,	1},
+    {"strcaseLower",	ASSEM_1BYTE,	INST_STR_LOWER,		1,	1},
+    {"strcaseTitle",	ASSEM_1BYTE,	INST_STR_TITLE,		1,	1},
+    {"strcaseUpper",	ASSEM_1BYTE,	INST_STR_UPPER,		1,	1},
     {"strcmp",		ASSEM_1BYTE,	INST_STR_CMP,		2,	1},
+    {"strcat",		ASSEM_CONCAT1,	INST_STR_CONCAT1,	INT_MIN,1},
     {"streq",		ASSEM_1BYTE,	INST_STR_EQ,		2,	1},
     {"strfind",		ASSEM_1BYTE,	INST_STR_FIND,		2,	1},
     {"strindex",	ASSEM_1BYTE,	INST_STR_INDEX,		2,	1},
@@ -463,12 +469,17 @@ static const TalInstDesc TalInstructionTable[] = {
     {"strmatch",	ASSEM_BOOL,	INST_STR_MATCH,		2,	1},
     {"strneq",		ASSEM_1BYTE,	INST_STR_NEQ,		2,	1},
     {"strrange",	ASSEM_1BYTE,	INST_STR_RANGE,		3,	1},
+    {"strreplace",	ASSEM_1BYTE,	INST_STR_REPLACE,	4,	1},
     {"strrfind",	ASSEM_1BYTE,	INST_STR_FIND_LAST,	2,	1},
+    {"strtrim",		ASSEM_1BYTE,	INST_STR_TRIM,		2,	1},
+    {"strtrimLeft",	ASSEM_1BYTE,	INST_STR_TRIM_LEFT,	2,	1},
+    {"strtrimRight",	ASSEM_1BYTE,	INST_STR_TRIM_RIGHT,	2,	1},
     {"sub",		ASSEM_1BYTE,	INST_SUB,		2,	1},
     {"tclooClass",	ASSEM_1BYTE,	INST_TCLOO_CLASS,	1,	1},
     {"tclooIsObject",	ASSEM_1BYTE,	INST_TCLOO_IS_OBJECT,	1,	1},
     {"tclooNamespace",	ASSEM_1BYTE,	INST_TCLOO_NS,		1,	1},
     {"tclooSelf",	ASSEM_1BYTE,	INST_TCLOO_SELF,	0,	1},
+    {"tryCvtToBoolean",	ASSEM_1BYTE,	INST_TRY_CVT_TO_BOOLEAN,1,	2},
     {"tryCvtToNumeric",	ASSEM_1BYTE,	INST_TRY_CVT_TO_NUMERIC,1,	1},
     {"uminus",		ASSEM_1BYTE,	INST_UMINUS,		1,	1},
     {"unset",		ASSEM_BOOL_LVT4,INST_UNSET_SCALAR,	0,	0},
@@ -495,6 +506,7 @@ static const unsigned char NonThrowingByteCodes[] = {
     INST_PUSH1, INST_PUSH4, INST_POP, INST_DUP,			/* 1-4 */
     INST_JUMP1, INST_JUMP4,					/* 34-35 */
     INST_END_CATCH, INST_PUSH_RESULT, INST_PUSH_RETURN_CODE,	/* 70-72 */
+    INST_LIST,							/* 79 */
     INST_OVER,							/* 95 */
     INST_PUSH_RETURN_OPTIONS,					/* 108 */
     INST_REVERSE,						/* 126 */
@@ -504,7 +516,11 @@ static const unsigned char NonThrowingByteCodes[] = {
     INST_COROUTINE_NAME,					/* 149 */
     INST_NS_CURRENT,						/* 151 */
     INST_INFO_LEVEL_NUM,					/* 152 */
-    INST_RESOLVE_COMMAND					/* 154 */
+    INST_RESOLVE_COMMAND,					/* 154 */
+    INST_STR_TRIM, INST_STR_TRIM_LEFT, INST_STR_TRIM_RIGHT,	/* 166-168 */
+    INST_CONCAT_STK,						/* 169 */
+    INST_STR_UPPER, INST_STR_LOWER, INST_STR_TITLE,		/* 170-172 */
+    INST_NUM_TYPE						/* 180 */
 };
 
 /*
@@ -681,13 +697,10 @@ BBEmitInstInt4(
 /*
  *-----------------------------------------------------------------------------
  *
- * BBEmitInst1or4, BBEmitInvoke1or4 --
+ * BBEmitInst1or4 --
  *
  *	Emits a 1- or 4-byte operation according to the magnitude of the
- *	operand. The Invoke variant generates wrapping stack-balance
- *	management if necessary (which is not normally required in assembled
- *	code, as loop exception ranges, expansions, breaks and continues can't
- *	be issued currently).
+ *	operand.
  *
  *-----------------------------------------------------------------------------
  */
@@ -719,29 +732,6 @@ BBEmitInst1or4(
     TclUpdateAtCmdStart(op, envPtr);
     BBUpdateStackReqs(bbPtr, tblIdx, count);
 }
-
-static void
-BBEmitInvoke1or4(
-    AssemblyEnv* assemEnvPtr,	/* Assembly environment */
-    int tblIdx,			/* Index in TalInstructionTable of op */
-    int param,			/* Variable-length parameter */
-    int count)			/* Arity if variadic */
-{
-    CompileEnv* envPtr = assemEnvPtr->envPtr;
-				/* Compilation environment */
-    BasicBlock* bbPtr = assemEnvPtr->curr_bb;
-				/* Current basic block */
-    int op = TalInstructionTable[tblIdx].tclInstCode;
-
-    if (param <= 0xff) {
-	op >>= 8;
-    } else {
-	op &= 0xff;
-    }
-    TclEmitInvoke(envPtr, op, param);
-    TclUpdateAtCmdStart(op, envPtr);
-    BBUpdateStackReqs(bbPtr, tblIdx, count);
-}
 
 /*
  *-----------------------------------------------------------------------------
@@ -1478,7 +1468,7 @@ AssembleOneLine(
 	    goto cleanup;
 	}
 
-	BBEmitInvoke1or4(assemEnvPtr, tblIdx, opnd, opnd);
+	BBEmitInst1or4(assemEnvPtr, tblIdx, opnd, opnd);
 	break;
 
     case ASSEM_JUMP:
diff --git a/generic/tclBasic.c b/generic/tclBasic.c
index a41351e..2a334c4 100644
--- a/generic/tclBasic.c
+++ b/generic/tclBasic.c
@@ -211,7 +211,7 @@ static const CmdInfo builtInCmds[] = {
     {"case",		Tcl_CaseObjCmd,		NULL,			NULL,	CMD_IS_SAFE},
 #endif
     {"catch",		Tcl_CatchObjCmd,	TclCompileCatchCmd,	TclNRCatchObjCmd,	CMD_IS_SAFE},
-    {"concat",		Tcl_ConcatObjCmd,	NULL,			NULL,	CMD_IS_SAFE},
+    {"concat",		Tcl_ConcatObjCmd,	TclCompileConcatCmd,	NULL,	CMD_IS_SAFE},
     {"continue",	Tcl_ContinueObjCmd,	TclCompileContinueCmd,	NULL,	CMD_IS_SAFE},
     {"coroutine",	NULL,			NULL,			TclNRCoroutineObjCmd,	CMD_IS_SAFE},
     {"error",		Tcl_ErrorObjCmd,	TclCompileErrorCmd,	NULL,	CMD_IS_SAFE},
@@ -227,7 +227,7 @@ static const CmdInfo builtInCmds[] = {
     {"lappend",		Tcl_LappendObjCmd,	TclCompileLappendCmd,	NULL,	CMD_IS_SAFE},
     {"lassign",		Tcl_LassignObjCmd,	TclCompileLassignCmd,	NULL,	CMD_IS_SAFE},
     {"lindex",		Tcl_LindexObjCmd,	TclCompileLindexCmd,	NULL,	CMD_IS_SAFE},
-    {"linsert",		Tcl_LinsertObjCmd,	NULL,			NULL,	CMD_IS_SAFE},
+    {"linsert",		Tcl_LinsertObjCmd,	TclCompileLinsertCmd,	NULL,	CMD_IS_SAFE},
     {"list",		Tcl_ListObjCmd,		TclCompileListCmd,	NULL,	CMD_IS_SAFE|CMD_COMPILES_EXPANDED},
     {"llength",		Tcl_LlengthObjCmd,	TclCompileLlengthCmd,	NULL,	CMD_IS_SAFE},
     {"lmap",		Tcl_LmapObjCmd,		TclCompileLmapCmd,	TclNRLmapCmd,	CMD_IS_SAFE},
@@ -259,7 +259,7 @@ static const CmdInfo builtInCmds[] = {
     {"variable",	Tcl_VariableObjCmd,	TclCompileVariableCmd,	NULL,	CMD_IS_SAFE},
     {"while",		Tcl_WhileObjCmd,	TclCompileWhileCmd,	TclNRWhileObjCmd,	CMD_IS_SAFE},
     {"yield",		NULL,			TclCompileYieldCmd,	TclNRYieldObjCmd,	CMD_IS_SAFE},
-    {"yieldto",		NULL,			NULL,			TclNRYieldToObjCmd,	CMD_IS_SAFE},
+    {"yieldto",		NULL,			TclCompileYieldToCmd,	TclNRYieldToObjCmd,	CMD_IS_SAFE},
 
     /*
      * Commands in the OS-interface. Note that many of these are unsafe.
@@ -526,6 +526,9 @@ Tcl_CreateInterp(void)
     iPtr->hiddenCmdTablePtr = NULL;
     iPtr->interpInfo = NULL;
 
+    TCL_CT_ASSERT(sizeof(iPtr->extra) <= sizeof(Tcl_HashTable));
+    iPtr->extra.optimizer = TclOptimizeBytecode;
+
     iPtr->numLevels = 0;
     iPtr->maxNestingDepth = MAX_NESTING_DEPTH;
     iPtr->framePtr = NULL;	/* Initialise as soon as :: is available */
@@ -2082,10 +2085,19 @@ Tcl_CreateCommand(
 	 */
 
 	cmdPtr = Tcl_GetHashValue(hPtr);
-	oldRefPtr = cmdPtr->importRefPtr;
-	cmdPtr->importRefPtr = NULL;
+	cmdPtr->refCount++;
+	if (cmdPtr->importRefPtr) {
+	    cmdPtr->flags |= CMD_REDEF_IN_PROGRESS;
+	}
 
 	Tcl_DeleteCommandFromToken(interp, (Tcl_Command) cmdPtr);
+
+	if (cmdPtr->flags & CMD_REDEF_IN_PROGRESS) {
+	    oldRefPtr = cmdPtr->importRefPtr;
+	    cmdPtr->importRefPtr = NULL;
+	}
+	TclCleanupCommandMacro(cmdPtr);
+
 	hPtr = Tcl_CreateHashEntry(&nsPtr->cmdTable, tail, &isNew);
 	if (!isNew) {
 	    /*
@@ -2269,10 +2281,19 @@ Tcl_CreateObjCommand(
 	 * intact.
 	 */
 
-	oldRefPtr = cmdPtr->importRefPtr;
-	cmdPtr->importRefPtr = NULL;
+	cmdPtr->refCount++;
+	if (cmdPtr->importRefPtr) {
+	    cmdPtr->flags |= CMD_REDEF_IN_PROGRESS;
+	}
 
 	Tcl_DeleteCommandFromToken(interp, (Tcl_Command) cmdPtr);
+
+	if (cmdPtr->flags & CMD_REDEF_IN_PROGRESS) {
+	    oldRefPtr = cmdPtr->importRefPtr;
+	    cmdPtr->importRefPtr = NULL;
+	}
+	TclCleanupCommandMacro(cmdPtr);
+
 	hPtr = Tcl_CreateHashEntry(&nsPtr->cmdTable, tail, &isNew);
 	if (!isNew) {
 	    /*
@@ -3114,12 +3135,13 @@ Tcl_DeleteCommandFromToken(
      * commands were created that refer back to this command. Delete these
      * imported commands now.
      */
-
-    for (refPtr = cmdPtr->importRefPtr; refPtr != NULL;
-	    refPtr = nextRefPtr) {
-	nextRefPtr = refPtr->nextPtr;
-	importCmd = (Tcl_Command) refPtr->importedCmdPtr;
-	Tcl_DeleteCommandFromToken(interp, importCmd);
+    if (!(cmdPtr->flags & CMD_REDEF_IN_PROGRESS)) {
+	for (refPtr = cmdPtr->importRefPtr; refPtr != NULL;
+		refPtr = nextRefPtr) {
+	    nextRefPtr = refPtr->nextPtr;
+	    importCmd = (Tcl_Command) refPtr->importedCmdPtr;
+	    Tcl_DeleteCommandFromToken(interp, importCmd);
+	}
     }
 
     /*
@@ -8413,8 +8435,7 @@ TclNRYieldToObjCmd(
 {
     CoroutineData *corPtr = iPtr->execEnvPtr->corPtr;
     Tcl_Obj *listPtr, *nsObjPtr;
-    Tcl_Namespace *nsPtr = (Tcl_Namespace *) iPtr->varFramePtr->nsPtr;
-    Tcl_Namespace *ns1Ptr;
+    Tcl_Namespace *nsPtr = TclGetCurrentNamespace(interp);
 
     if (objc < 2) {
 	Tcl_WrongNumArgs(interp, 1, objv, "command ?arg ...?");
@@ -8428,11 +8449,13 @@ TclNRYieldToObjCmd(
 	return TCL_ERROR;
     }
 
-    /*
-     * Add the tailcall in the caller env, then just yield.
-     *
-     * This is essentially code from TclNRTailcallObjCmd
-     */
+    if (((Namespace *) nsPtr)->flags & NS_DYING) {
+        Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		"yieldto called in deleted namespace", -1));
+        Tcl_SetErrorCode(interp, "TCL", "COROUTINE", "YIELDTO_IN_DELETED",
+		NULL);
+        return TCL_ERROR;
+    }
 
     /*
      * Add the tailcall in the caller env, then just yield.
@@ -8441,15 +8464,9 @@ TclNRYieldToObjCmd(
      */
 
     listPtr = Tcl_NewListObj(objc, objv);
-
     nsObjPtr = Tcl_NewStringObj(nsPtr->fullName, -1);
-    if ((TCL_OK != TclGetNamespaceFromObj(interp, nsObjPtr, &ns1Ptr))
-	    || (nsPtr != ns1Ptr)) {
-	Tcl_Panic("yieldto failed to find the proper namespace");
-    }
     TclListObjSetElement(interp, listPtr, 0, nsObjPtr);
 
-
     /*
      * Add the callback in the caller's env, then instruct TEBC to yield.
      */
diff --git a/generic/tclBinary.c b/generic/tclBinary.c
index 4e977f2..981f174 100644
--- a/generic/tclBinary.c
+++ b/generic/tclBinary.c
@@ -610,9 +610,7 @@ UpdateStringOfByteArray(
  *
  *	This function appends an array of bytes to a byte array object. Note
  *	that the object *must* be unshared, and the array of bytes *must not*
- *	refer to the object being appended to.  Also the caller must have
- *	already checked that the final length of the bytearray after the
- *	append operations is complete will not overflow the int range.
+ *	refer to the object being appended to.
  *
  * Results:
  *	None.
@@ -631,6 +629,7 @@ TclAppendBytesToByteArray(
     int len)
 {
     ByteArray *byteArrayPtr;
+    int needed;
 
     if (Tcl_IsShared(objPtr)) {
 	Tcl_Panic("%s called with shared object","TclAppendBytesToByteArray");
@@ -639,64 +638,57 @@ TclAppendBytesToByteArray(
 	Tcl_Panic("%s must be called with definite number of bytes to append",
 		"TclAppendBytesToByteArray");
     }
+    if (len == 0) {
+	/* Append zero bytes is a no-op. */
+	return;
+    }
     if (objPtr->typePtr != &tclByteArrayType) {
 	SetByteArrayFromAny(NULL, objPtr);
     }
     byteArrayPtr = GET_BYTEARRAY(objPtr);
 
+    if (len > INT_MAX - byteArrayPtr->used) {
+	Tcl_Panic("max size for a Tcl value (%d bytes) exceeded", INT_MAX);
+    }
+
+    needed = byteArrayPtr->used + len;
     /*
      * If we need to, resize the allocated space in the byte array.
      */
 
-    if (byteArrayPtr->used + len > byteArrayPtr->allocated) {
-	unsigned int attempt, used = byteArrayPtr->used;
-	ByteArray *tmpByteArrayPtr = NULL;
+    if (needed > byteArrayPtr->allocated) {
+	ByteArray *ptr = NULL;
+	int attempt;
 
-	attempt = byteArrayPtr->allocated;
-	if (attempt < 1) {
-	    /*
-	     * No allocated bytes, so must be none used too. We use this
-	     * method to calculate how many bytes to allocate because we can
-	     * end up with a zero-length buffer otherwise, when doubling can
-	     * cause trouble. [Bug 3067036]
-	     */
-
-	    attempt = len + 1;
-	} else {
-	    do {
-		attempt *= 2;
-	    } while (attempt < used+len);
+	if (needed <= INT_MAX/2) {
+	    /* Try to allocate double the total space that is needed. */
+	    attempt = 2 * needed;
+	    ptr = attemptckrealloc(byteArrayPtr, BYTEARRAY_SIZE(attempt));
 	}
+	if (ptr == NULL) {
+	    /* Try to allocate double the increment that is needed (plus). */
+	    unsigned int limit = INT_MAX - needed;
+	    unsigned int extra = len + TCL_MIN_GROWTH;
+	    int growth = (int) ((extra > limit) ? limit : extra);
 
-	if (BYTEARRAY_SIZE(attempt) > BYTEARRAY_SIZE(used)) {
-	    tmpByteArrayPtr = attemptckrealloc(byteArrayPtr,
-		    BYTEARRAY_SIZE(attempt));
+	    attempt = needed + growth;
+	    ptr = attemptckrealloc(byteArrayPtr, BYTEARRAY_SIZE(attempt));
 	}
-
-	if (tmpByteArrayPtr == NULL) {
-	    attempt = used + len;
-	    if (BYTEARRAY_SIZE(attempt) < BYTEARRAY_SIZE(used)) {
-		Tcl_Panic("attempt to allocate a bigger buffer than we can handle");
-	    }
-	    tmpByteArrayPtr = ckrealloc(byteArrayPtr,
-		    BYTEARRAY_SIZE(attempt));
+	if (ptr == NULL) {
+	    /* Last chance: Try to allocate exactly what is needed. */
+	    attempt = needed;
+	    ptr = ckrealloc(byteArrayPtr, BYTEARRAY_SIZE(attempt));
 	}
-
-	byteArrayPtr = tmpByteArrayPtr;
+	byteArrayPtr = ptr;
 	byteArrayPtr->allocated = attempt;
-	byteArrayPtr->used = used;
 	SET_BYTEARRAY(objPtr, byteArrayPtr);
     }
 
-    /*
-     * Do the append if there's any point.
-     */
-
-    if (len > 0) {
+    if (bytes) {
 	memcpy(byteArrayPtr->bytes + byteArrayPtr->used, bytes, len);
-	byteArrayPtr->used += len;
-	TclInvalidateStringRep(objPtr);
     }
+    byteArrayPtr->used += len;
+    TclInvalidateStringRep(objPtr);
 }
 
 /*
diff --git a/generic/tclClock.c b/generic/tclClock.c
index 6d2976d..50d480c 100644
--- a/generic/tclClock.c
+++ b/generic/tclClock.c
@@ -19,7 +19,7 @@
  * Windows has mktime. The configurators do not check.
  */
 
-#ifdef __WIN32__
+#ifdef _WIN32
 #define HAVE_MKTIME 1
 #endif
 
diff --git a/generic/tclCmdAH.c b/generic/tclCmdAH.c
index f90819a..d90a747 100644
--- a/generic/tclCmdAH.c
+++ b/generic/tclCmdAH.c
@@ -1590,7 +1590,7 @@ FileAttrIsOwnedCmd(
 	 * test for equivalence to the current user.
 	 */
 
-#if defined(__WIN32__) || defined(__CYGWIN__)
+#if defined(_WIN32) || defined(__CYGWIN__)
 	value = 1;
 #else
 	value = (geteuid() == buf.st_uid);
diff --git a/generic/tclCmdIL.c b/generic/tclCmdIL.c
index fa4ead4..41c1eb6 100644
--- a/generic/tclCmdIL.c
+++ b/generic/tclCmdIL.c
@@ -1147,41 +1147,38 @@ InfoFrameCmd(
     Tcl_Obj *const objv[])	/* Argument objects. */
 {
     Interp *iPtr = (Interp *) interp;
-    int level, topLevel, code = TCL_OK;
-    CmdFrame *runPtr, *framePtr;
+    int level, code = TCL_OK;
+    CmdFrame *framePtr, **cmdFramePtrPtr = &iPtr->cmdFramePtr;
     CoroutineData *corPtr = iPtr->execEnvPtr->corPtr;
+    int topLevel = 0;
 
     if (objc > 2) {
 	Tcl_WrongNumArgs(interp, 1, objv, "?number?");
 	return TCL_ERROR;
     }
 
-    topLevel = ((iPtr->cmdFramePtr == NULL)
-	    ? 0
-	    : iPtr->cmdFramePtr->level);
-
-    if (corPtr) {
-	/*
-	 * A coroutine: must fix the level computations AND the cmdFrame chain,
-	 * which is interrupted at the base.
-	 */
-
-	CmdFrame *lastPtr = NULL;
-
-	runPtr = iPtr->cmdFramePtr;
+    while (corPtr) {
+	while (*cmdFramePtrPtr) {
+	    topLevel++;
+	    cmdFramePtrPtr = &((*cmdFramePtrPtr)->nextPtr);
+	}
+	if (corPtr->caller.cmdFramePtr) {
+	    *cmdFramePtrPtr = corPtr->caller.cmdFramePtr;
+	}
+	corPtr = corPtr->callerEEPtr->corPtr;
+    }
+    topLevel += (*cmdFramePtrPtr)->level;
 
-	/* TODO - deal with overflow */
-	topLevel += corPtr->caller.cmdFramePtr->level;
-	while (runPtr) {
-	    runPtr->level += corPtr->caller.cmdFramePtr->level;
-	    lastPtr = runPtr;
-	    runPtr = runPtr->nextPtr;
+    if (topLevel != iPtr->cmdFramePtr->level) {
+	framePtr = iPtr->cmdFramePtr;
+	while (framePtr) {
+	    framePtr->level = topLevel--;
+	    framePtr = framePtr->nextPtr;
 	}
-	if (lastPtr) {
-	    lastPtr->nextPtr = corPtr->caller.cmdFramePtr;
-	} else {
-	    iPtr->cmdFramePtr = corPtr->caller.cmdFramePtr;
+	if (topLevel) {
+	    Tcl_Panic("Broken frame level calculation");
 	}
+	topLevel = iPtr->cmdFramePtr->level;
     }
 
     if (objc == 1) {
@@ -1231,20 +1228,27 @@ InfoFrameCmd(
     Tcl_SetObjResult(interp, TclInfoFrame(interp, framePtr));
 
   done:
-    if (corPtr) {
+    cmdFramePtrPtr = &iPtr->cmdFramePtr;
+    corPtr = iPtr->execEnvPtr->corPtr;
+    while (corPtr) {
+	CmdFrame *endPtr = corPtr->caller.cmdFramePtr;
+
+	if (endPtr) {
+	    if (*cmdFramePtrPtr == endPtr) {
+		*cmdFramePtrPtr = NULL;
+	    } else {
+		CmdFrame *runPtr = *cmdFramePtrPtr;
 
-	if (iPtr->cmdFramePtr == corPtr->caller.cmdFramePtr) {
-	    iPtr->cmdFramePtr = NULL;
-	} else {
-	    runPtr = iPtr->cmdFramePtr;
-	    while (runPtr->nextPtr != corPtr->caller.cmdFramePtr) {
-	    	runPtr->level -= corPtr->caller.cmdFramePtr->level;
-		runPtr = runPtr->nextPtr;
+		while (runPtr->nextPtr != endPtr) {
+		    runPtr->level -= endPtr->level;
+		    runPtr = runPtr->nextPtr;
+		}
+		runPtr->level = 1;
+		runPtr->nextPtr = NULL;
 	    }
-	    runPtr->level = 1;
-	    runPtr->nextPtr = NULL;
+	    cmdFramePtrPtr = &corPtr->caller.cmdFramePtr;
 	}
-
+	corPtr = corPtr->callerEEPtr->corPtr;
     }
     return code;
 }
diff --git a/generic/tclCmdMZ.c b/generic/tclCmdMZ.c
index 5087fbb..00c9f2f 100644
--- a/generic/tclCmdMZ.c
+++ b/generic/tclCmdMZ.c
@@ -18,6 +18,7 @@
 
 #include "tclInt.h"
 #include "tclRegexp.h"
+#include "tclStringTrim.h"
 
 static inline Tcl_Obj *	During(Tcl_Interp *interp, int resultCode,
 			    Tcl_Obj *oldOptions, Tcl_Obj *errorInfo);
@@ -37,32 +38,33 @@ static int		UniCharIsHexDigit(int character);
  * UTF-8 literal string containing all Unicode space characters [TIP #413]
  */
 
-#define DEFAULT_TRIM_SET \
-	"\x09\x0a\x0b\x0c\x0d " /* ASCII */\
-	"\xc0\x80" /*     nul (U+0000) */\
-	"\xc2\x85" /*     next line (U+0085) */\
-	"\xc2\xa0" /*     non-breaking space (U+00a0) */\
-	"\xe1\x9a\x80" /* ogham space mark (U+1680) */ \
-	"\xe1\xa0\x8e" /* mongolian vowel separator (U+180e) */\
-	"\xe2\x80\x80" /* en quad (U+2000) */\
-	"\xe2\x80\x81" /* em quad (U+2001) */\
-	"\xe2\x80\x82" /* en space (U+2002) */\
-	"\xe2\x80\x83" /* em space (U+2003) */\
-	"\xe2\x80\x84" /* three-per-em space (U+2004) */\
-	"\xe2\x80\x85" /* four-per-em space (U+2005) */\
-	"\xe2\x80\x86" /* six-per-em space (U+2006) */\
-	"\xe2\x80\x87" /* figure space (U+2007) */\
-	"\xe2\x80\x88" /* punctuation space (U+2008) */\
-	"\xe2\x80\x89" /* thin space (U+2009) */\
-	"\xe2\x80\x8a" /* hair space (U+200a) */\
-	"\xe2\x80\x8b" /* zero width space (U+200b) */\
-	"\xe2\x80\xa8" /* line separator (U+2028) */\
-	"\xe2\x80\xa9" /* paragraph separator (U+2029) */\
-	"\xe2\x80\xaf" /* narrow no-break space (U+202f) */\
-	"\xe2\x81\x9f" /* medium mathematical space (U+205f) */\
-	"\xe2\x81\xa0" /* word joiner (U+2060) */\
-	"\xe3\x80\x80" /* ideographic space (U+3000) */\
+const char tclDefaultTrimSet[] = 
+	"\x09\x0a\x0b\x0c\x0d " /* ASCII */
+	"\xc0\x80" /*     nul (U+0000) */
+	"\xc2\x85" /*     next line (U+0085) */
+	"\xc2\xa0" /*     non-breaking space (U+00a0) */
+	"\xe1\x9a\x80" /* ogham space mark (U+1680) */
+	"\xe1\xa0\x8e" /* mongolian vowel separator (U+180e) */
+	"\xe2\x80\x80" /* en quad (U+2000) */
+	"\xe2\x80\x81" /* em quad (U+2001) */
+	"\xe2\x80\x82" /* en space (U+2002) */
+	"\xe2\x80\x83" /* em space (U+2003) */
+	"\xe2\x80\x84" /* three-per-em space (U+2004) */
+	"\xe2\x80\x85" /* four-per-em space (U+2005) */
+	"\xe2\x80\x86" /* six-per-em space (U+2006) */
+	"\xe2\x80\x87" /* figure space (U+2007) */
+	"\xe2\x80\x88" /* punctuation space (U+2008) */
+	"\xe2\x80\x89" /* thin space (U+2009) */
+	"\xe2\x80\x8a" /* hair space (U+200a) */
+	"\xe2\x80\x8b" /* zero width space (U+200b) */
+	"\xe2\x80\xa8" /* line separator (U+2028) */
+	"\xe2\x80\xa9" /* paragraph separator (U+2029) */
+	"\xe2\x80\xaf" /* narrow no-break space (U+202f) */
+	"\xe2\x81\x9f" /* medium mathematical space (U+205f) */
+	"\xe2\x81\xa0" /* word joiner (U+2060) */
+	"\xe3\x80\x80" /* ideographic space (U+3000) */
 	"\xef\xbb\xbf" /* zero width no-break space (U+feff) */
+;
 
 /*
  *----------------------------------------------------------------------
@@ -3189,8 +3191,8 @@ StringTrimCmd(
     if (objc == 3) {
 	string2 = TclGetStringFromObj(objv[2], &length2);
     } else if (objc == 2) {
-	string2 = DEFAULT_TRIM_SET;
-	length2 = strlen(DEFAULT_TRIM_SET);
+	string2 = tclDefaultTrimSet;
+	length2 = strlen(tclDefaultTrimSet);
     } else {
 	Tcl_WrongNumArgs(interp, 1, objv, "string ?chars?");
 	return TCL_ERROR;
@@ -3237,8 +3239,8 @@ StringTrimLCmd(
     if (objc == 3) {
 	string2 = TclGetStringFromObj(objv[2], &length2);
     } else if (objc == 2) {
-	string2 = DEFAULT_TRIM_SET;
-	length2 = strlen(DEFAULT_TRIM_SET);
+	string2 = tclDefaultTrimSet;
+	length2 = strlen(tclDefaultTrimSet);
     } else {
 	Tcl_WrongNumArgs(interp, 1, objv, "string ?chars?");
 	return TCL_ERROR;
@@ -3283,8 +3285,8 @@ StringTrimRCmd(
     if (objc == 3) {
 	string2 = TclGetStringFromObj(objv[2], &length2);
     } else if (objc == 2) {
-	string2 = DEFAULT_TRIM_SET;
-	length2 = strlen(DEFAULT_TRIM_SET);
+	string2 = tclDefaultTrimSet;
+	length2 = strlen(tclDefaultTrimSet);
     } else {
 	Tcl_WrongNumArgs(interp, 1, objv, "string ?chars?");
 	return TCL_ERROR;
@@ -3330,21 +3332,21 @@ TclInitStringCmd(
 	{"equal",	StringEqualCmd,	TclCompileStringEqualCmd, NULL, NULL, 0},
 	{"first",	StringFirstCmd,	TclCompileStringFirstCmd, NULL, NULL, 0},
 	{"index",	StringIndexCmd,	TclCompileStringIndexCmd, NULL, NULL, 0},
-	{"is",		StringIsCmd,	NULL, NULL, NULL, 0},
+	{"is",		StringIsCmd,	TclCompileStringIsCmd, NULL, NULL, 0},
 	{"last",	StringLastCmd,	TclCompileStringLastCmd, NULL, NULL, 0},
 	{"length",	StringLenCmd,	TclCompileStringLenCmd, NULL, NULL, 0},
 	{"map",		StringMapCmd,	TclCompileStringMapCmd, NULL, NULL, 0},
 	{"match",	StringMatchCmd,	TclCompileStringMatchCmd, NULL, NULL, 0},
 	{"range",	StringRangeCmd,	TclCompileStringRangeCmd, NULL, NULL, 0},
 	{"repeat",	StringReptCmd,	TclCompileBasic2ArgCmd, NULL, NULL, 0},
-	{"replace",	StringRplcCmd,	NULL, NULL, NULL, 0},
+	{"replace",	StringRplcCmd,	TclCompileStringReplaceCmd, NULL, NULL, 0},
 	{"reverse",	StringRevCmd,	TclCompileBasic1ArgCmd, NULL, NULL, 0},
-	{"tolower",	StringLowerCmd,	TclCompileBasic1To3ArgCmd, NULL, NULL, 0},
-	{"toupper",	StringUpperCmd,	TclCompileBasic1To3ArgCmd, NULL, NULL, 0},
-	{"totitle",	StringTitleCmd,	TclCompileBasic1To3ArgCmd, NULL, NULL, 0},
-	{"trim",	StringTrimCmd,	TclCompileBasic1Or2ArgCmd, NULL, NULL, 0},
-	{"trimleft",	StringTrimLCmd,	TclCompileBasic1Or2ArgCmd, NULL, NULL, 0},
-	{"trimright",	StringTrimRCmd,	TclCompileBasic1Or2ArgCmd, NULL, NULL, 0},
+	{"tolower",	StringLowerCmd,	TclCompileStringToLowerCmd, NULL, NULL, 0},
+	{"toupper",	StringUpperCmd,	TclCompileStringToUpperCmd, NULL, NULL, 0},
+	{"totitle",	StringTitleCmd,	TclCompileStringToTitleCmd, NULL, NULL, 0},
+	{"trim",	StringTrimCmd,	TclCompileStringTrimCmd, NULL, NULL, 0},
+	{"trimleft",	StringTrimLCmd,	TclCompileStringTrimLCmd, NULL, NULL, 0},
+	{"trimright",	StringTrimRCmd,	TclCompileStringTrimRCmd, NULL, NULL, 0},
 	{"wordend",	StringEndCmd,	TclCompileBasic2ArgCmd, NULL, NULL, 0},
 	{"wordstart",	StringStartCmd,	TclCompileBasic2ArgCmd, NULL, NULL, 0},
 	{NULL, NULL, NULL, NULL, NULL, 0}
diff --git a/generic/tclCompCmds.c b/generic/tclCompCmds.c
index 9c43bfe..d1d7a80 100644
--- a/generic/tclCompCmds.c
+++ b/generic/tclCompCmds.c
@@ -31,6 +31,9 @@ static void		FreeForeachInfo(ClientData clientData);
 static void		PrintForeachInfo(ClientData clientData,
 			    Tcl_Obj *appendObj, ByteCode *codePtr,
 			    unsigned int pcOffset);
+static void		PrintNewForeachInfo(ClientData clientData,
+			    Tcl_Obj *appendObj, ByteCode *codePtr,
+			    unsigned int pcOffset);
 static int		CompileEachloopCmd(Tcl_Interp *interp,
 			    Tcl_Parse *parsePtr, Command *cmdPtr,
 			    CompileEnv *envPtr, int collect);
@@ -49,6 +52,13 @@ const AuxDataType tclForeachInfoType = {
     PrintForeachInfo		/* printProc */
 };
 
+const AuxDataType tclNewForeachInfoType = {
+    "NewForeachInfo",		/* name */
+    DupForeachInfo,		/* dupProc */
+    FreeForeachInfo,		/* freeProc */
+    PrintNewForeachInfo		/* printProc */
+};
+
 const AuxDataType tclDictUpdateInfoType = {
     "DictUpdateInfo",		/* name */
     DupDictUpdateInfo,		/* dupProc */
@@ -245,8 +255,8 @@ TclCompileArraySetCmd(
     Tcl_Token *varTokenPtr, *dataTokenPtr;
     int isScalar, localIndex, code = TCL_OK;
     int isDataLiteral, isDataValid, isDataEven, len;
-    int dataVar, iterVar, keyVar, valVar, infoIndex;
-    int back, fwd, offsetBack, offsetFwd;
+    int keyVar, valVar, infoIndex;
+    int fwd, offsetBack, offsetFwd;
     Tcl_Obj *literalObj;
     ForeachInfo *infoPtr;
 
@@ -268,7 +278,7 @@ TclCompileArraySetCmd(
 
     if (isDataValid && !isDataEven) {
 	PushStringLiteral(envPtr, "list must have an even number of elements");
-	PushStringLiteral(envPtr, "-errorCode {TCL ARGUMENT FORMAT}");
+	PushStringLiteral(envPtr, "-errorcode {TCL ARGUMENT FORMAT}");
 	TclEmitInstInt4(INST_RETURN_IMM, TCL_ERROR,		envPtr);
 	TclEmitInt4(		0,				envPtr);
 	goto done;
@@ -290,6 +300,7 @@ TclCompileArraySetCmd(
 	code = TCL_ERROR;
 	goto done;
     }
+
     /*
      * Special case: literal empty value argument is just an "ensure array"
      * operation.
@@ -314,20 +325,29 @@ TclCompileArraySetCmd(
 	goto done;
     }
 
+    if (localIndex < 0) {
+	/*
+	 * a non-local variable: upvar from a local one! This consumes the
+	 * variable name that was left at stacktop.
+	 */
+	
+	localIndex = AnonymousLocal(envPtr);
+	PushStringLiteral(envPtr, "0");
+	TclEmitInstInt4(INST_REVERSE, 2,        		envPtr);
+	TclEmitInstInt4(INST_UPVAR, localIndex, 		envPtr);
+	TclEmitOpcode(INST_POP,          			envPtr);
+    }
+    
     /*
      * Prepare for the internal foreach.
      */
 
-    dataVar = AnonymousLocal(envPtr);
-    iterVar = AnonymousLocal(envPtr);
     keyVar = AnonymousLocal(envPtr);
     valVar = AnonymousLocal(envPtr);
 
-    infoPtr = ckalloc(sizeof(ForeachInfo) + sizeof(ForeachVarList *));
+    infoPtr = ckalloc(sizeof(ForeachInfo));
     infoPtr->numLists = 1;
-    infoPtr->firstValueTemp = dataVar;
-    infoPtr->loopCtTemp = iterVar;
-    infoPtr->varLists[0] = ckalloc(sizeof(ForeachVarList) * 2*sizeof(int));
+    infoPtr->varLists[0] = ckalloc(sizeof(ForeachVarList) + sizeof(int));
     infoPtr->varLists[0]->numVars = 2;
     infoPtr->varLists[0]->varIndexes[0] = keyVar;
     infoPtr->varLists[0]->varIndexes[1] = valVar;
@@ -353,61 +373,30 @@ TclCompileArraySetCmd(
 	offsetFwd = CurrentOffset(envPtr);
 	TclEmitInstInt1(INST_JUMP_FALSE1, 0,			envPtr);
 	PushStringLiteral(envPtr, "list must have an even number of elements");
-	PushStringLiteral(envPtr, "-errorCode {TCL ARGUMENT FORMAT}");
+	PushStringLiteral(envPtr, "-errorcode {TCL ARGUMENT FORMAT}");
 	TclEmitInstInt4(INST_RETURN_IMM, TCL_ERROR,		envPtr);
 	TclEmitInt4(		0,				envPtr);
 	TclAdjustStackDepth(-1, envPtr);
 	fwd = CurrentOffset(envPtr) - offsetFwd;
 	TclStoreInt1AtPtr(fwd, envPtr->codeStart+offsetFwd+1);
     }
-    Emit14Inst(		INST_STORE_SCALAR, dataVar,		envPtr);
-    TclEmitOpcode(	INST_POP,				envPtr);
 
-    if (localIndex >= 0) {
-	TclEmitInstInt4(INST_ARRAY_EXISTS_IMM, localIndex,	envPtr);
-	TclEmitInstInt1(INST_JUMP_TRUE1, 7,			envPtr);
-	TclEmitInstInt4(INST_ARRAY_MAKE_IMM, localIndex,	envPtr);
-	TclEmitInstInt4(INST_FOREACH_START4, infoIndex,		envPtr);
-	offsetBack = CurrentOffset(envPtr);
-	TclEmitInstInt4(INST_FOREACH_STEP4, infoIndex,		envPtr);
-	offsetFwd = CurrentOffset(envPtr);
-	TclEmitInstInt1(INST_JUMP_FALSE1, 0,			envPtr);
-	Emit14Inst(	INST_LOAD_SCALAR, keyVar,		envPtr);
-	Emit14Inst(	INST_LOAD_SCALAR, valVar,		envPtr);
-	Emit14Inst(	INST_STORE_ARRAY, localIndex,		envPtr);
-	TclEmitOpcode(	INST_POP,				envPtr);
-	back = offsetBack - CurrentOffset(envPtr);
-	TclEmitInstInt1(INST_JUMP1, back,			envPtr);
-	fwd = CurrentOffset(envPtr) - offsetFwd;
-	TclStoreInt1AtPtr(fwd, envPtr->codeStart+offsetFwd+1);
-    } else {
-	TclEmitOpcode(	INST_DUP,				envPtr);
-	TclEmitOpcode(	INST_ARRAY_EXISTS_STK,			envPtr);
-	TclEmitInstInt1(INST_JUMP_TRUE1, 4,			envPtr);
-	TclEmitOpcode(	INST_DUP,				envPtr);
-	TclEmitOpcode(	INST_ARRAY_MAKE_STK,			envPtr);
-	TclEmitInstInt4(INST_FOREACH_START4, infoIndex,		envPtr);
-	offsetBack = CurrentOffset(envPtr);
-	TclEmitInstInt4(INST_FOREACH_STEP4, infoIndex,		envPtr);
-	offsetFwd = CurrentOffset(envPtr);
-	TclEmitInstInt1(INST_JUMP_FALSE1, 0,			envPtr);
-	TclEmitOpcode(	INST_DUP,				envPtr);
-	Emit14Inst(	INST_LOAD_SCALAR, keyVar,		envPtr);
-	Emit14Inst(	INST_LOAD_SCALAR, valVar,		envPtr);
-	TclEmitOpcode(	INST_STORE_ARRAY_STK,			envPtr);
-	TclEmitOpcode(	INST_POP,				envPtr);
-	back = offsetBack - CurrentOffset(envPtr);
-	TclEmitInstInt1(INST_JUMP1, back,			envPtr);
-	fwd = CurrentOffset(envPtr) - offsetFwd;
-	TclStoreInt1AtPtr(fwd, envPtr->codeStart+offsetFwd+1);
-	TclEmitOpcode(	INST_POP,				envPtr);
-    }
-    if (!isDataLiteral) {
-	TclEmitInstInt1(INST_UNSET_SCALAR, 0,			envPtr);
-	TclEmitInt4(		dataVar,			envPtr);
-    }
+    TclEmitInstInt4(INST_ARRAY_EXISTS_IMM, localIndex,	envPtr);
+    TclEmitInstInt1(INST_JUMP_TRUE1, 7,			envPtr);
+    TclEmitInstInt4(INST_ARRAY_MAKE_IMM, localIndex,	envPtr);
+    TclEmitInstInt4(INST_FOREACH_START, infoIndex,	envPtr);
+    offsetBack = CurrentOffset(envPtr);
+    Emit14Inst(	INST_LOAD_SCALAR, keyVar,		envPtr);
+    Emit14Inst(	INST_LOAD_SCALAR, valVar,		envPtr);
+    Emit14Inst(	INST_STORE_ARRAY, localIndex,		envPtr);
+    TclEmitOpcode(	INST_POP,			envPtr);
+    infoPtr->loopCtTemp = offsetBack - CurrentOffset(envPtr); /*misuse */
+    TclEmitOpcode( INST_FOREACH_STEP,			envPtr);
+    TclEmitOpcode( INST_FOREACH_END,			envPtr);
+    TclAdjustStackDepth(-3, envPtr);
     PushStringLiteral(envPtr,	"");
-  done:
+
+    done:
     Tcl_DecrRefCount(literalObj);
     return code;
 }
@@ -500,17 +489,14 @@ TclCompileBreakCmd(
 
 	TclCleanupStackForBreakContinue(envPtr, auxPtr);
 	TclAddLoopBreakFixup(envPtr, auxPtr);
-	TclAdjustStackDepth(1, envPtr);
     } else {
 	/*
 	 * Emit a real break.
 	 */
 
-	PushStringLiteral(envPtr, "");
-	TclEmitOpcode(INST_DUP, envPtr);
-	TclEmitInstInt4(INST_RETURN_IMM, TCL_BREAK, envPtr);
-	TclEmitInt4(0, envPtr);
+	TclEmitOpcode(INST_BREAK, envPtr);
     }
+    TclAdjustStackDepth(1, envPtr);
 
     return TCL_OK;
 }
@@ -544,9 +530,10 @@ TclCompileCatchCmd(
 {
     JumpFixup jumpFixup;
     Tcl_Token *cmdTokenPtr, *resultNameTokenPtr, *optsNameTokenPtr;
-    int resultIndex, optsIndex, range;
+    int resultIndex, optsIndex, range, dropScript = 0;
     DefineLineInformation;	/* TIP #280 */
-
+    int depth = TclGetStackDepth(envPtr);
+    
     /*
      * If syntax does not match what we expect for [catch], do not compile.
      * Let runtime checks determine if syntax has changed.
@@ -593,11 +580,7 @@ TclCompileCatchCmd(
     /*
      * We will compile the catch command. Declare the exception range that it
      * uses.
-     */
-
-    range = TclCreateExceptRange(CATCH_EXCEPTION_RANGE, envPtr);
-
-    /*
+     *
      * If the body is a simple word, compile a BEGIN_CATCH instruction,
      * followed by the instructions to eval the body.
      * Otherwise, compile instructions to substitute the body text before
@@ -610,6 +593,7 @@ TclCompileCatchCmd(
      * begin by undeflowing the stack below the mark set by BEGIN_CATCH4.
      */
 
+    range = TclCreateExceptRange(CATCH_EXCEPTION_RANGE, envPtr);
     if (cmdTokenPtr->type == TCL_TOKEN_SIMPLE_WORD) {
 	TclEmitInstInt4(	INST_BEGIN_CATCH4, range,	envPtr);
 	ExceptionRangeStarts(envPtr, range);
@@ -621,70 +605,50 @@ TclCompileCatchCmd(
 	ExceptionRangeStarts(envPtr, range);
 	TclEmitOpcode(		INST_DUP,			envPtr);
 	TclEmitInvoke(envPtr,	INST_EVAL_STK);
-    }
-    /* Stack at this point:
-     *    nonsimple:  script <mark> result
-     *    simple:            <mark> result
-     */
-
-    if (resultIndex == -1) {
-	/*
-	 * Special case when neither result nor options are being saved. In
-	 * that case, we can skip quite a bit of the command epilogue; all we
-	 * have to do is drop the result and push the return code (and, of
-	 * course, finish the catch context).
-	 */
-
+	/* drop the script */
+	dropScript = 1;
+	TclEmitInstInt4(	INST_REVERSE, 2,		envPtr);
 	TclEmitOpcode(		INST_POP,			envPtr);
-	PushStringLiteral(envPtr, "0");
-	TclEmitInstInt1(	INST_JUMP1, 3,			envPtr);
-	TclAdjustStackDepth(-1, envPtr);
-	ExceptionRangeTarget(envPtr, range, catchOffset);
-	TclEmitOpcode(		INST_PUSH_RETURN_CODE,		envPtr);
-	ExceptionRangeEnds(envPtr, range);
-	TclEmitOpcode(		INST_END_CATCH,			envPtr);
-
-	/*
-	 * Stack at this point:
-	 *    nonsimple:  script <mark> returnCode
-	 *    simple:            <mark> returnCode
-	 */
-
-	goto dropScriptAtEnd;
     }
+    ExceptionRangeEnds(envPtr, range);
 
+    
     /*
      * Emit the "no errors" epilogue: push "0" (TCL_OK) as the catch result,
      * and jump around the "error case" code.
      */
 
+    TclCheckStackDepth(depth+1, envPtr);
     PushStringLiteral(envPtr, "0");
     TclEmitForwardJump(envPtr, TCL_UNCONDITIONAL_JUMP, &jumpFixup);
-    /* Stack at this point: ?script? <mark> result TCL_OK */
 
     /* 
      * Emit the "error case" epilogue. Push the interpreter result and the
      * return code.
      */
 
-    TclAdjustStackDepth(-2, envPtr);
     ExceptionRangeTarget(envPtr, range, catchOffset);
-    /* Stack at this point:  ?script? */
+    TclSetStackDepth(depth + dropScript, envPtr);
+    
+    if (dropScript) {
+	TclEmitOpcode(		INST_POP,			envPtr);
+    }
+
+
+    /* Stack at this point is empty */
     TclEmitOpcode(		INST_PUSH_RESULT,		envPtr);
     TclEmitOpcode(		INST_PUSH_RETURN_CODE,		envPtr);
 
-    /*
-     * Update the target of the jump after the "no errors" code. 
-     */
+    /* Stack at this point on both branches: result returnCode */
 
-    /* Stack at this point: ?script? result returnCode */
     if (TclFixupForwardJumpToHere(envPtr, &jumpFixup, 127)) {
 	Tcl_Panic("TclCompileCatchCmd: bad jump distance %d",
 		(int)(CurrentOffset(envPtr) - jumpFixup.codeOffset));
     }
 
     /*
-     * Push the return options if the caller wants them.
+     * Push the return options if the caller wants them. This needs to happen
+     * before INST_END_CATCH
      */
 
     if (optsIndex != -1) {
@@ -695,53 +659,118 @@ TclCompileCatchCmd(
      * End the catch
      */
 
-    ExceptionRangeEnds(envPtr, range);
     TclEmitOpcode(		INST_END_CATCH,			envPtr);
 
     /*
-     * At this point, the top of the stack is inconveniently ordered:
-     *		?script? result returnCode ?returnOptions?
-     * Reverse the stack to bring the result to the top.
+     * Save the result and return options if the caller wants them. This needs
+     * to happen after INST_END_CATCH (compile-3.6/7).
      */
 
     if (optsIndex != -1) {
-	TclEmitInstInt4(	INST_REVERSE, 3,		envPtr);
-    } else {
-	TclEmitInstInt4(	INST_REVERSE, 2,		envPtr);
+	Emit14Inst(		INST_STORE_SCALAR, optsIndex,	envPtr);
+	TclEmitOpcode(		INST_POP,			envPtr);
     }
 
     /*
-     * Store the result and remove it from the stack.
+     * At this point, the top of the stack is inconveniently ordered:
+     *		result returnCode
+     * Reverse the stack to store the result.
      */
 
-    Emit14Inst(			INST_STORE_SCALAR, resultIndex,	envPtr);
-    TclEmitOpcode(		INST_POP,			envPtr);
+    TclEmitInstInt4(	INST_REVERSE, 2,		envPtr);
+    if (resultIndex != -1) {
+	Emit14Inst(	INST_STORE_SCALAR, resultIndex,	envPtr);
+    }
+    TclEmitOpcode(	INST_POP,			envPtr);
+
+    TclCheckStackDepth(depth+1, envPtr);
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclCompileConcatCmd --
+ *
+ *	Procedure called to compile the "concat" command.
+ *
+ * Results:
+ *	Returns TCL_OK for a successful compile. Returns TCL_ERROR to defer
+ *	evaluation to runtime.
+ *
+ * Side effects:
+ *	Instructions are added to envPtr to execute the "concat" command at
+ *	runtime.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+TclCompileConcatCmd(
+    Tcl_Interp *interp,		/* Used for error reporting. */
+    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
+				 * created by Tcl_ParseCommand. */
+    Command *cmdPtr,		/* Points to defintion of command being
+				 * compiled. */
+    CompileEnv *envPtr)		/* Holds resulting instructions. */
+{
+    DefineLineInformation;	/* TIP #280 */
+    Tcl_Obj *objPtr, *listObj;
+    Tcl_Token *tokenPtr;
+    int i;
+
+    /* TODO: Consider compiling expansion case. */
+    if (parsePtr->numWords == 1) {
+	/*
+	 * [concat] without arguments just pushes an empty object.
+	 */
+
+	PushStringLiteral(envPtr, "");
+	return TCL_OK;
+    }
 
     /*
-     * Stack is now ?script? ?returnOptions? returnCode.
-     * If the options dict has been requested, it is buried on the stack under
-     * the return code. Reverse the stack to bring it to the top, store it and
-     * remove it from the stack.
+     * Test if all arguments are compile-time known. If they are, we can
+     * implement with a simple push.
      */
 
-    if (optsIndex != -1) {
-	TclEmitInstInt4(	INST_REVERSE, 2,		envPtr);
-	Emit14Inst(		INST_STORE_SCALAR, optsIndex,	envPtr);
-	TclEmitOpcode(		INST_POP,			envPtr);
+    listObj = Tcl_NewObj();
+    for (i = 1, tokenPtr = parsePtr->tokenPtr; i < parsePtr->numWords; i++) {
+	tokenPtr = TokenAfter(tokenPtr);
+	objPtr = Tcl_NewObj();
+	if (!TclWordKnownAtCompileTime(tokenPtr, objPtr)) {
+	    Tcl_DecrRefCount(objPtr);
+	    Tcl_DecrRefCount(listObj);
+	    listObj = NULL;
+	    break;
+	}
+	(void) Tcl_ListObjAppendElement(NULL, listObj, objPtr);
     }
+    if (listObj != NULL) {
+	Tcl_Obj **objs;
+	const char *bytes;
+	int len;
 
-  dropScriptAtEnd:
+	Tcl_ListObjGetElements(NULL, listObj, &len, &objs);
+	objPtr = Tcl_ConcatObj(len, objs);
+	Tcl_DecrRefCount(listObj);
+	bytes = Tcl_GetStringFromObj(objPtr, &len);
+	PushLiteral(envPtr, bytes, len);
+	Tcl_DecrRefCount(objPtr);
+	return TCL_OK;
+    }
 
     /*
-     * Stack is now ?script? result. Get rid of the subst'ed script if it's
-     * hanging arond.
+     * General case: runtime concat.
      */
 
-    if (cmdTokenPtr->type != TCL_TOKEN_SIMPLE_WORD) {
-	TclEmitInstInt4(	INST_REVERSE, 2,		envPtr);
-	TclEmitOpcode(		INST_POP,			envPtr);
+    for (i = 1, tokenPtr = parsePtr->tokenPtr; i < parsePtr->numWords; i++) {
+	tokenPtr = TokenAfter(tokenPtr);
+	CompileWord(envPtr, tokenPtr, interp, i);
     }
 
+    TclEmitInstInt4(	INST_CONCAT_STK, i-1,		envPtr);
+
     return TCL_OK;
 }
 
@@ -796,17 +825,14 @@ TclCompileContinueCmd(
 
 	TclCleanupStackForBreakContinue(envPtr, auxPtr);
 	TclAddLoopContinueFixup(envPtr, auxPtr);
-	TclAdjustStackDepth(1, envPtr);
     } else {
 	/*
 	 * Emit a real continue.
 	 */
 
-	PushStringLiteral(envPtr, "");
-	TclEmitOpcode(INST_DUP, envPtr);
-	TclEmitInstInt4(INST_RETURN_IMM, TCL_CONTINUE, envPtr);
-	TclEmitInt4(0, envPtr);
+	TclEmitOpcode(INST_CONTINUE, envPtr);
     }
+    TclAdjustStackDepth(1, envPtr);
 
     return TCL_OK;
 }
@@ -1739,7 +1765,7 @@ TclCompileDictAppendCmd(
 	tokenPtr = TokenAfter(tokenPtr);
     }
     if (parsePtr->numWords > 4) {
-	TclEmitInstInt1(INST_CONCAT1, parsePtr->numWords-3, envPtr);
+	TclEmitInstInt1(INST_STR_CONCAT1, parsePtr->numWords-3, envPtr);
     }
 
     /*
@@ -2342,6 +2368,7 @@ TclCompileForCmd(
 
     SetLineInformation(2);
     TclCompileExprWords(interp, testTokenPtr, 1, envPtr);
+    TclClearNumConversion(envPtr);
 
     jumpDist = CurrentOffset(envPtr) - bodyCodeOffset;
     if (jumpDist > 127) {
@@ -2469,18 +2496,10 @@ CompileEachloopCmd(
     ForeachInfo *infoPtr;	/* Points to the structure describing this
 				 * foreach command. Stored in a AuxData
 				 * record in the ByteCode. */
-    int firstValueTemp;		/* Index of the first temp var in the frame
-				 * used to point to a value list. */
-    int loopCtTemp;		/* Index of temp var holding the loop's
-				 * iteration count. */
-    int collectVar = -1;	/* Index of temp var holding the result var
-				 * index. */
-
+    
     Tcl_Token *tokenPtr, *bodyTokenPtr;
-    unsigned char *jumpPc;
-    JumpFixup jumpFalseFixup;
-    int jumpBackDist, jumpBackOffset, infoIndex, range;
-    int numWords, numLists, numVars, loopIndex, tempVar, i, j, code;
+    int jumpBackOffset, infoIndex, range;
+    int numWords, numLists, numVars, loopIndex, i, j, code;
     DefineLineInformation;	/* TIP #280 */
 
     /*
@@ -2588,32 +2607,11 @@ CompileEachloopCmd(
 	loopIndex++;
     }
 
-    if (collect == TCL_EACH_COLLECT) {
-	collectVar = AnonymousLocal(envPtr);
-	if (collectVar < 0) {
-	    return TCL_ERROR;
-	}
-    }
-	    
     /*
-     * We will compile the foreach command. Reserve (numLists + 1) temporary
-     * variables:
-     *    - numLists temps to hold each value list
-     *    - 1 temp for the loop counter (index of next element in each list)
-     *
-     * At this time we don't try to reuse temporaries; if there are two
-     * nonoverlapping foreach loops, they don't share any temps.
+     * We will compile the foreach command.
      */
 
     code = TCL_OK;
-    firstValueTemp = -1;
-    for (loopIndex = 0;  loopIndex < numLists;  loopIndex++) {
-	tempVar = AnonymousLocal(envPtr);
-	if (loopIndex == 0) {
-	    firstValueTemp = tempVar;
-	}
-    }
-    loopCtTemp = AnonymousLocal(envPtr);
 
     /*
      * Create and initialize the ForeachInfo and ForeachVarList data
@@ -2622,16 +2620,14 @@ CompileEachloopCmd(
      */
 
     infoPtr = ckalloc(sizeof(ForeachInfo)
-	    + numLists * sizeof(ForeachVarList *));
+	    + (numLists - 1) * sizeof(ForeachVarList *));
     infoPtr->numLists = numLists;
-    infoPtr->firstValueTemp = firstValueTemp;
-    infoPtr->loopCtTemp = loopCtTemp;
     for (loopIndex = 0;  loopIndex < numLists;  loopIndex++) {
 	ForeachVarList *varListPtr;
 
 	numVars = varcList[loopIndex];
 	varListPtr = ckalloc(sizeof(ForeachVarList)
-		+ numVars * sizeof(int));
+		+ (numVars - 1) * sizeof(int));
 	varListPtr->numVars = numVars;
 	for (j = 0;  j < numVars;  j++) {
 	    const char *varName = varvList[loopIndex][j];
@@ -2642,131 +2638,77 @@ CompileEachloopCmd(
 	}
 	infoPtr->varLists[loopIndex] = varListPtr;
     }
-    infoIndex = TclCreateAuxData(infoPtr, &tclForeachInfoType, envPtr);
+    infoIndex = TclCreateAuxData(infoPtr, &tclNewForeachInfoType, envPtr);
 
     /*
-     * Create an exception record to handle [break] and [continue].
+     * Create the collecting object, unshared.
      */
-
-    range = TclCreateExceptRange(LOOP_EXCEPTION_RANGE, envPtr);
-
+    
+    if (collect == TCL_EACH_COLLECT) {
+	TclEmitInstInt4(INST_LIST, 0, envPtr);
+    }
+	    
     /*
-     * Evaluate then store each value list in the associated temporary.
+     * Evaluate each value list and leave it on stack.
      */
 
-    loopIndex = 0;
     for (i = 0, tokenPtr = parsePtr->tokenPtr;
 	    i < numWords-1;
 	    i++, tokenPtr = TokenAfter(tokenPtr)) {
 	if ((i%2 == 0) && (i > 0)) {
 	    CompileWord(envPtr, tokenPtr, interp, i);
-	    tempVar = (firstValueTemp + loopIndex);
-	    Emit14Inst(		INST_STORE_SCALAR, tempVar,	envPtr);
-	    TclEmitOpcode(	INST_POP,			envPtr);
-	    loopIndex++;
 	}
     }
 
-    /*
-     * Create temporary variable to capture return values from loop body.
-     */
-     
-    if (collect == TCL_EACH_COLLECT) {
-	PushStringLiteral(envPtr, "");
-	Emit14Inst(		INST_STORE_SCALAR, collectVar,	envPtr);
-	TclEmitOpcode(		INST_POP,			envPtr);
-    }
-
-    /*
-     * Initialize the temporary var that holds the count of loop iterations.
-     */
-
-    TclEmitInstInt4(		INST_FOREACH_START4, infoIndex,	envPtr);
-
-    /*
-     * Top of loop code: assign each loop variable and check whether
-     * to terminate the loop.
-     */
-
-    ExceptionRangeTarget(envPtr, range, continueOffset);
-    TclEmitInstInt4(		INST_FOREACH_STEP4, infoIndex,	envPtr);
-    TclEmitForwardJump(envPtr, TCL_FALSE_JUMP, &jumpFalseFixup);
-
+    TclEmitInstInt4(INST_FOREACH_START, infoIndex, envPtr);
+    
     /*
      * Inline compile the loop body.
      */
 
+    range = TclCreateExceptRange(LOOP_EXCEPTION_RANGE, envPtr);
+
     ExceptionRangeStarts(envPtr, range);
     BODY(bodyTokenPtr, numWords - 1);
     ExceptionRangeEnds(envPtr, range);
-
+    
     if (collect == TCL_EACH_COLLECT) {
-	Emit14Inst(		INST_LAPPEND_SCALAR, collectVar,envPtr);
-    }
-    TclEmitOpcode(		INST_POP,			envPtr);
-
-    /*
-     * Jump back to the test at the top of the loop. Generate a 4 byte jump if
-     * the distance to the test is > 120 bytes. This is conservative and
-     * ensures that we won't have to replace this jump if we later need to
-     * replace the ifFalse jump with a 4 byte jump.
-     */
-
-    jumpBackOffset = CurrentOffset(envPtr);
-    jumpBackDist = jumpBackOffset-envPtr->exceptArrayPtr[range].continueOffset;
-    if (jumpBackDist > 120) {
-	TclEmitInstInt4(INST_JUMP4, -jumpBackDist, envPtr);
+	TclEmitOpcode(INST_LMAP_COLLECT, envPtr);
     } else {
-	TclEmitInstInt1(INST_JUMP1, -jumpBackDist, envPtr);
+	TclEmitOpcode(		INST_POP,			envPtr);
     }
 
     /*
-     * Fix the target of the jump after the foreach_step test.
+     * Bottom of loop code: assign each loop variable and check whether
+     * to terminate the loop. Set the loop's break target. 
      */
 
-    if (TclFixupForwardJumpToHere(envPtr, &jumpFalseFixup, 127)) {
-	/*
-	 * Update the loop body's starting PC offset since it moved down.
-	 */
-
-	envPtr->exceptArrayPtr[range].codeOffset += 3;
-
-	/*
-	 * Update the jump back to the test at the top of the loop since it
-	 * also moved down 3 bytes.
-	 */
-
-	jumpBackOffset += 3;
-	jumpPc = (envPtr->codeStart + jumpBackOffset);
-	jumpBackDist += 3;
-	if (jumpBackDist > 120) {
-	    TclUpdateInstInt4AtPc(INST_JUMP4, -jumpBackDist, jumpPc);
-	} else {
-	    TclUpdateInstInt1AtPc(INST_JUMP1, -jumpBackDist, jumpPc);
-	}
-    }
+    ExceptionRangeTarget(envPtr, range, continueOffset);
+    TclEmitOpcode(INST_FOREACH_STEP, envPtr);
+    ExceptionRangeTarget(envPtr, range, breakOffset);
+    TclFinalizeLoopExceptionRange(envPtr, range);
+    TclEmitOpcode(INST_FOREACH_END, envPtr);
+    TclAdjustStackDepth(-(numLists+2), envPtr);
 
     /*
-     * Set the loop's break target.
+     * Set the jumpback distance from INST_FOREACH_STEP to the start of the
+     * body's code. Misuse loopCtTemp for storing the jump size.
      */
-
-    ExceptionRangeTarget(envPtr, range, breakOffset);
-    TclFinalizeLoopExceptionRange(envPtr, range);
+    
+    jumpBackOffset = envPtr->exceptArrayPtr[range].continueOffset -
+	    envPtr->exceptArrayPtr[range].codeOffset;
+    infoPtr->loopCtTemp = -jumpBackOffset;
 
     /*
-     * The command's result is an empty string if not collecting, or the
-     * list of results from evaluating the loop body.
+     * The command's result is an empty string if not collecting. If
+     * collecting, it is automatically left on stack after FOREACH_END.
      */
 
-    if (collect == TCL_EACH_COLLECT) {
-	Emit14Inst(		INST_LOAD_SCALAR, collectVar,	envPtr);
-	TclEmitInstInt1(INST_UNSET_SCALAR, 0,			envPtr);
-	TclEmitInt4(		collectVar,			envPtr);
-    } else {
+    if (collect != TCL_EACH_COLLECT) {
 	PushStringLiteral(envPtr, "");
     }
-
-  done:
+    
+    done:
     for (loopIndex = 0;  loopIndex < numLists;  loopIndex++) {
 	if (varvList[loopIndex] != NULL) {
 	    ckfree(varvList[loopIndex]);
@@ -2920,6 +2862,36 @@ PrintForeachInfo(
 	Tcl_AppendToObj(appendObj, "]", -1);
     }
 }
+
+static void
+PrintNewForeachInfo(
+    ClientData clientData,
+    Tcl_Obj *appendObj,
+    ByteCode *codePtr,
+    unsigned int pcOffset)
+{
+    register ForeachInfo *infoPtr = clientData;
+    register ForeachVarList *varsPtr;
+    int i, j;
+
+    Tcl_AppendPrintfToObj(appendObj, "jumpOffset=%+d, vars=",
+	    infoPtr->loopCtTemp);
+    for (i=0 ; i<infoPtr->numLists ; i++) {
+	if (i) {
+	    Tcl_AppendToObj(appendObj, ",", -1);
+	}
+	Tcl_AppendToObj(appendObj, "[", -1);
+	varsPtr = infoPtr->varLists[i];
+	for (j=0 ; j<varsPtr->numVars ; j++) {
+	    if (j) {
+		Tcl_AppendToObj(appendObj, ",", -1);
+	    }
+	    Tcl_AppendPrintfToObj(appendObj, "%%v%u",
+		    (unsigned) varsPtr->varIndexes[j]);
+	}
+	Tcl_AppendToObj(appendObj, "]", -1);
+    }
+}
 
 /*
  *----------------------------------------------------------------------
@@ -3126,7 +3098,7 @@ TclCompileFormatCmd(
 	 * Do the concatenation, which produces the result.
 	 */
 
-	TclEmitInstInt1(INST_CONCAT1, i, envPtr);
+	TclEmitInstInt1(INST_STR_CONCAT1, i, envPtr);
     } else {
 	/*
 	 * EVIL HACK! Force there to be a string representation in the case
diff --git a/generic/tclCompCmdsGR.c b/generic/tclCompCmdsGR.c
index d00327d..b3e273f 100644
--- a/generic/tclCompCmdsGR.c
+++ b/generic/tclCompCmdsGR.c
@@ -28,6 +28,58 @@ static void		CompileReturnInternal(CompileEnv *envPtr,
 static int		IndexTailVarIfKnown(Tcl_Interp *interp,
 			    Tcl_Token *varTokenPtr, CompileEnv *envPtr);
 
+#define INDEX_END	(-2)
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * GetIndexFromToken --
+ *
+ *	Parse a token and get the encoded version of the index (as understood
+ *	by TEBC), assuming it is at all knowable at compile time. Only handles
+ *	indices that are integers or 'end' or 'end-integer'.
+ *
+ * Returns:
+ *	TCL_OK if parsing succeeded, and TCL_ERROR if it failed.
+ *
+ * Side effects:
+ *	Sets *index to the index value if successful.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static inline int
+GetIndexFromToken(
+    Tcl_Token *tokenPtr,
+    int *index)
+{
+    Tcl_Obj *tmpObj = Tcl_NewObj();
+    int result, idx;
+
+    if (!TclWordKnownAtCompileTime(tokenPtr, tmpObj)) {
+	Tcl_DecrRefCount(tmpObj);
+	return TCL_ERROR;
+    }
+
+    result = TclGetIntFromObj(NULL, tmpObj, &idx);
+    if (result == TCL_OK) {
+	if (idx < 0) {
+	    result = TCL_ERROR;
+	}
+    } else {
+	result = TclGetIntForIndexM(NULL, tmpObj, INDEX_END, &idx);
+	if (result == TCL_OK && idx > INDEX_END) {
+	    result = TCL_ERROR;
+	}
+    }
+    Tcl_DecrRefCount(tmpObj);
+
+    if (result == TCL_OK) {
+	*index = idx;
+    }
+
+    return result;
+}
 
 /*
  *----------------------------------------------------------------------
@@ -229,6 +281,7 @@ TclCompileIfCmd(
 		SetLineInformation(wordIdx);
 		Tcl_ResetResult(interp);
 		TclCompileExprWords(interp, testTokenPtr, 1, envPtr);
+		TclClearNumConversion(envPtr);
 		if (jumpFalseFixupArray.next >= jumpFalseFixupArray.end) {
 		    TclExpandJumpFixupArray(&jumpFalseFixupArray);
 		}
@@ -478,6 +531,7 @@ TclCompileIncrCmd(
 	} else {
 	    SetLineInformation(2);
 	    CompileTokens(envPtr, incrTokenPtr, interp);
+	    TclClearNumConversion(envPtr);
 	}
     } else {			/* No incr amount given so use 1. */
 	haveImmValue = 1;
@@ -1027,7 +1081,7 @@ TclCompileLassignCmd(
      */
 
     TclEmitInstInt4(		INST_LIST_RANGE_IMM, idx,	envPtr);
-    TclEmitInt4(		-2 /* == "end" */,		envPtr);
+    TclEmitInt4(			INDEX_END,		envPtr);
 
     return TCL_OK;
 }
@@ -1060,7 +1114,7 @@ TclCompileLindexCmd(
     CompileEnv *envPtr)		/* Holds resulting instructions. */
 {
     Tcl_Token *idxTokenPtr, *valTokenPtr;
-    int i, numWords = parsePtr->numWords;
+    int i, idx, numWords = parsePtr->numWords;
     DefineLineInformation;	/* TIP #280 */
 
     /*
@@ -1078,46 +1132,28 @@ TclCompileLindexCmd(
     }
 
     idxTokenPtr = TokenAfter(valTokenPtr);
-    if (idxTokenPtr->type == TCL_TOKEN_SIMPLE_WORD) {
-	Tcl_Obj *tmpObj;
-	int idx, result;
-
-	tmpObj = Tcl_NewStringObj(idxTokenPtr[1].start, idxTokenPtr[1].size);
-	result = TclGetIntFromObj(NULL, tmpObj, &idx);
-	if (result == TCL_OK) {
-	    if (idx < 0) {
-		result = TCL_ERROR;
-	    }
-	} else {
-	    result = TclGetIntForIndexM(NULL, tmpObj, -2, &idx);
-	    if (result == TCL_OK && idx > -2) {
-		result = TCL_ERROR;
-	    }
-	}
-	TclDecrRefCount(tmpObj);
-
-	if (result == TCL_OK) {
-	    /*
-	     * All checks have been completed, and we have exactly one of
-	     * these constructs:
-	     *	 lindex <arbitraryValue> <posInt>
-	     *	 lindex <arbitraryValue> end-<posInt>
-	     * This is best compiled as a push of the arbitrary value followed
-	     * by an "immediate lindex" which is the most efficient variety.
-	     */
-
-	    CompileWord(envPtr, valTokenPtr, interp, 1);
-	    TclEmitInstInt4(	INST_LIST_INDEX_IMM, idx,	envPtr);
-	    return TCL_OK;
-	}
-
+    if (GetIndexFromToken(idxTokenPtr, &idx) == TCL_OK) {
 	/*
-	 * If the conversion failed or the value was negative, we just keep on
-	 * going with the more complex compilation.
+	 * All checks have been completed, and we have exactly one of these
+	 * constructs:
+	 *	 lindex <arbitraryValue> <posInt>
+	 *	 lindex <arbitraryValue> end-<posInt>
+	 * This is best compiled as a push of the arbitrary value followed by
+	 * an "immediate lindex" which is the most efficient variety.
 	 */
+
+	CompileWord(envPtr, valTokenPtr, interp, 1);
+	TclEmitInstInt4(	INST_LIST_INDEX_IMM, idx,	envPtr);
+	return TCL_OK;
     }
 
     /*
+     * If the value was not known at compile time, the conversion failed or
+     * the value was negative, we just keep on going with the more complex
+     * compilation.
+     */
+
+    /*
      * Push the operands onto the stack.
      */
 
@@ -1263,7 +1299,7 @@ TclCompileListCmd(
 
     if (concat && numWords == 2) {
 	TclEmitInstInt4(	INST_LIST_RANGE_IMM, 0,	envPtr);
-	TclEmitInt4(			-2,		envPtr);
+	TclEmitInt4(			INDEX_END,	envPtr);
     }
     return TCL_OK;
 }
@@ -1330,8 +1366,7 @@ TclCompileLrangeCmd(
 {
     Tcl_Token *tokenPtr, *listTokenPtr;
     DefineLineInformation;	/* TIP #280 */
-    Tcl_Obj *tmpObj;
-    int idx1, idx2, result;
+    int idx1, idx2;
 
     if (parsePtr->numWords != 4) {
 	return TCL_ERROR;
@@ -1339,56 +1374,18 @@ TclCompileLrangeCmd(
     listTokenPtr = TokenAfter(parsePtr->tokenPtr);
 
     /*
-     * Parse the first index. Will only compile if it is constant and not an
+     * Parse the indices. Will only compile if both are constants and not an
      * _integer_ less than zero (since we reserve negative indices here for
-     * end-relative indexing).
+     * end-relative indexing) or an end-based index greater than 'end' itself.
      */
 
     tokenPtr = TokenAfter(listTokenPtr);
-    if (tokenPtr->type != TCL_TOKEN_SIMPLE_WORD) {
-	return TCL_ERROR;
-    }
-    tmpObj = Tcl_NewStringObj(tokenPtr[1].start, tokenPtr[1].size);
-    result = TclGetIntFromObj(NULL, tmpObj, &idx1);
-    if (result == TCL_OK) {
-	if (idx1 < 0) {
-	    result = TCL_ERROR;
-	}
-    } else {
-	result = TclGetIntForIndexM(NULL, tmpObj, -2, &idx1);
-	if (result == TCL_OK && idx1 > -2) {
-	    result = TCL_ERROR;
-	}
-    }
-    TclDecrRefCount(tmpObj);
-    if (result != TCL_OK) {
+    if (GetIndexFromToken(tokenPtr, &idx1) != TCL_OK) {
 	return TCL_ERROR;
     }
 
-    /*
-     * Parse the second index. Will only compile if it is constant and not an
-     * _integer_ less than zero (since we reserve negative indices here for
-     * end-relative indexing).
-     */
-
     tokenPtr = TokenAfter(tokenPtr);
-    if (tokenPtr->type != TCL_TOKEN_SIMPLE_WORD) {
-	return TCL_ERROR;
-    }
-    tmpObj = Tcl_NewStringObj(tokenPtr[1].start, tokenPtr[1].size);
-    result = TclGetIntFromObj(NULL, tmpObj, &idx2);
-    if (result == TCL_OK) {
-	if (idx2 < 0) {
-	    result = TCL_ERROR;
-	}
-    } else {
-	result = TclGetIntForIndexM(NULL, tmpObj, -2, &idx2);
-	if (result == TCL_OK && idx2 > -2) {
-	    result = TCL_ERROR;
-	}
-    }
-    TclDecrRefCount(tmpObj);
-    if (result != TCL_OK) {
+    if (GetIndexFromToken(tokenPtr, &idx2) != TCL_OK) {
 	return TCL_ERROR;
     }
 
@@ -1407,19 +1404,16 @@ TclCompileLrangeCmd(
 /*
  *----------------------------------------------------------------------
  *
- * TclCompileLreplaceCmd --
+ * TclCompileLinsertCmd --
  *
- *	How to compile the "lreplace" command. We only bother with the case
- *	where there are no elements to insert and where both the 'first' and
- *	'last' arguments are constant and one can be deterined to be at the
- *	end of the list. (This is the case that could also be written with
- *	"lrange".)
+ *	How to compile the "linsert" command. We only bother with the case
+ *	where the index is constant.
  *
  *----------------------------------------------------------------------
  */
 
 int
-TclCompileLreplaceCmd(
+TclCompileLinsertCmd(
     Tcl_Interp *interp,		/* Tcl interpreter for context. */
     Tcl_Parse *parsePtr,	/* Points to a parse structure for the
 				 * command. */
@@ -1429,101 +1423,272 @@ TclCompileLreplaceCmd(
 {
     Tcl_Token *tokenPtr, *listTokenPtr;
     DefineLineInformation;	/* TIP #280 */
-    Tcl_Obj *tmpObj;
-    int idx1, idx2, result, guaranteedDropAll = 0;
+    int idx, i;
 
-    if (parsePtr->numWords != 4) {
+    if (parsePtr->numWords < 3) {
 	return TCL_ERROR;
     }
     listTokenPtr = TokenAfter(parsePtr->tokenPtr);
 
     /*
-     * Parse the first index. Will only compile if it is constant and not an
+     * Parse the index. Will only compile if it is constant and not an
      * _integer_ less than zero (since we reserve negative indices here for
-     * end-relative indexing).
+     * end-relative indexing) or an end-based index greater than 'end' itself.
      */
 
     tokenPtr = TokenAfter(listTokenPtr);
-    if (tokenPtr->type != TCL_TOKEN_SIMPLE_WORD) {
+    if (GetIndexFromToken(tokenPtr, &idx) != TCL_OK) {
 	return TCL_ERROR;
     }
-    tmpObj = Tcl_NewStringObj(tokenPtr[1].start, tokenPtr[1].size);
-    result = TclGetIntFromObj(NULL, tmpObj, &idx1);
-    if (result == TCL_OK) {
-	if (idx1 < 0) {
-	    result = TCL_ERROR;
-	}
+
+    /*
+     * There are four main cases. If there are no values to insert, this is
+     * just a confirm-listiness check. If the index is '0', this is a prepend.
+     * If the index is 'end' (== INDEX_END), this is an append. Otherwise,
+     * this is a splice (== split, insert values as list, concat-3).
+     */
+
+    CompileWord(envPtr, listTokenPtr, interp, 1);
+    if (parsePtr->numWords == 3) {
+	TclEmitInstInt4(	INST_LIST_RANGE_IMM, 0,		envPtr);
+	TclEmitInt4(			INDEX_END,		envPtr);
+	return TCL_OK;
+    }
+
+    for (i=3 ; i<parsePtr->numWords ; i++) {
+	tokenPtr = TokenAfter(tokenPtr);
+	CompileWord(envPtr, tokenPtr, interp, i);
+    }
+    TclEmitInstInt4(		INST_LIST, i-3,			envPtr);
+
+    if (idx == 0 /*start*/) {
+	TclEmitInstInt4(	INST_REVERSE, 2,		envPtr);
+	TclEmitOpcode(		INST_LIST_CONCAT,		envPtr);
+    } else if (idx == INDEX_END /*end*/) {
+	TclEmitOpcode(		INST_LIST_CONCAT,		envPtr);
     } else {
-	result = TclGetIntForIndexM(NULL, tmpObj, -2, &idx1);
-	if (result == TCL_OK && idx1 > -2) {
-	    result = TCL_ERROR;
+	if (idx < 0) {
+	    idx++;
 	}
+	TclEmitInstInt4(	INST_OVER, 1,			envPtr);
+	TclEmitInstInt4(	INST_LIST_RANGE_IMM, 0,		envPtr);
+	TclEmitInt4(			idx-1,			envPtr);
+	TclEmitInstInt4(	INST_REVERSE, 3,		envPtr);
+	TclEmitInstInt4(	INST_LIST_RANGE_IMM, idx,	envPtr);
+	TclEmitInt4(			INDEX_END,		envPtr);
+	TclEmitOpcode(		INST_LIST_CONCAT,		envPtr);
+	TclEmitOpcode(		INST_LIST_CONCAT,		envPtr);
     }
-    TclDecrRefCount(tmpObj);
-    if (result != TCL_OK) {
+
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclCompileLreplaceCmd --
+ *
+ *	How to compile the "lreplace" command. We only bother with the case
+ *	where the indices are constant.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+TclCompileLreplaceCmd(
+    Tcl_Interp *interp,		/* Tcl interpreter for context. */
+    Tcl_Parse *parsePtr,	/* Points to a parse structure for the
+				 * command. */
+    Command *cmdPtr,		/* Points to defintion of command being
+				 * compiled. */
+    CompileEnv *envPtr)		/* Holds the resulting instructions. */
+{
+    Tcl_Token *tokenPtr, *listTokenPtr;
+    DefineLineInformation;	/* TIP #280 */
+    Tcl_Obj *tmpObj;
+    int idx1, idx2, i, offset;
+
+    if (parsePtr->numWords < 4) {
 	return TCL_ERROR;
     }
+    listTokenPtr = TokenAfter(parsePtr->tokenPtr);
 
     /*
-     * Parse the second index. Will only compile if it is constant and not an
+     * Parse the indices. Will only compile if both are constants and not an
      * _integer_ less than zero (since we reserve negative indices here for
-     * end-relative indexing).
+     * end-relative indexing) or an end-based index greater than 'end' itself.
      */
 
-    tokenPtr = TokenAfter(tokenPtr);
-    if (tokenPtr->type != TCL_TOKEN_SIMPLE_WORD) {
+    tokenPtr = TokenAfter(listTokenPtr);
+    if (GetIndexFromToken(tokenPtr, &idx1) != TCL_OK) {
 	return TCL_ERROR;
     }
-    tmpObj = Tcl_NewStringObj(tokenPtr[1].start, tokenPtr[1].size);
-    result = TclGetIntFromObj(NULL, tmpObj, &idx2);
-    if (result == TCL_OK) {
-	if (idx2 < 0) {
-	    result = TCL_ERROR;
-	}
-    } else {
-	result = TclGetIntForIndexM(NULL, tmpObj, -2, &idx2);
-	if (result == TCL_OK && idx2 > -2) {
-	    result = TCL_ERROR;
-	}
-    }
-    TclDecrRefCount(tmpObj);
-    if (result != TCL_OK) {
+
+    tokenPtr = TokenAfter(tokenPtr);
+    if (GetIndexFromToken(tokenPtr, &idx2) != TCL_OK) {
 	return TCL_ERROR;
     }
 
     /*
-     * Sanity check: can only issue when we're removing a range at one or
-     * other end of the list. If we're at one end or the other, convert the
-     * indices into the equivalent for an [lrange].
+     * Work out what this [lreplace] is actually doing.
      */
 
+    tmpObj = NULL;
+    CompileWord(envPtr, listTokenPtr, interp, 1);
+    if (parsePtr->numWords == 4) {
+	if (idx1 == 0) {
+	    if (idx2 == INDEX_END) {
+		goto dropAll;
+	    }
+	    idx1 = idx2 + 1;
+	    idx2 = INDEX_END;
+	    goto dropEnd;
+	} else if (idx2 == INDEX_END) {
+	    idx2 = idx1 - 1;
+	    idx1 = 0;
+	    goto dropEnd;
+	} else {
+	    if (idx1 > 0) {
+		tmpObj = Tcl_NewIntObj(idx1);
+		Tcl_IncrRefCount(tmpObj);
+	    }
+	    goto dropRange;
+	}
+    }
+
+    tokenPtr = TokenAfter(tokenPtr);
+    for (i=4 ; i<parsePtr->numWords ; i++) {
+	CompileWord(envPtr, tokenPtr, interp, i);
+	tokenPtr = TokenAfter(tokenPtr);
+    }
+    TclEmitInstInt4(		INST_LIST, i - 4,		envPtr);
+    TclEmitInstInt4(		INST_REVERSE, 2,		envPtr);
     if (idx1 == 0) {
-	if (idx2 == -2) {
-	    guaranteedDropAll = 1;
+	if (idx2 == INDEX_END) {
+	    goto replaceAll;
 	}
 	idx1 = idx2 + 1;
-	idx2 = -2;
-    } else if (idx2 == -2) {
+	idx2 = INDEX_END;
+	goto replaceHead;
+    } else if (idx2 == INDEX_END) {
 	idx2 = idx1 - 1;
 	idx1 = 0;
+	goto replaceTail;
     } else {
-	return TCL_ERROR;
+	if (idx1 > 0 && idx2 > 0 && idx2 < idx1) {
+	    idx2 = idx1 - 1;
+	} else if (idx1 < 0 && idx2 < 0 && idx2 < idx1) {
+	    idx2 = idx1 - 1;
+	}
+	if (idx1 > 0) {
+	    tmpObj = Tcl_NewIntObj(idx1);
+	    Tcl_IncrRefCount(tmpObj);
+	}
+	goto replaceRange;
     }
 
     /*
-     * Issue instructions. It's not safe to skip doing the LIST_RANGE, as
-     * we've not proved that the 'list' argument is really a list. Not that it
-     * is worth trying to do that given current knowledge.
+     * Issue instructions to perform the operations relating to configurations
+     * that just drop. The only argument pushed on the stack is the list to
+     * operate on.
      */
 
-    CompileWord(envPtr, listTokenPtr, interp, 1);
-    if (guaranteedDropAll) {
+  dropAll:
+    TclEmitOpcode(		INST_LIST_LENGTH,		envPtr);
+    TclEmitOpcode(		INST_POP,			envPtr);
+    PushStringLiteral(envPtr,	"");
+    goto done;
+
+  dropEnd:
+    TclEmitInstInt4(		INST_LIST_RANGE_IMM, idx1,	envPtr);
+    TclEmitInt4(			idx2,			envPtr);
+    goto done;
+
+  dropRange:
+    if (tmpObj != NULL) {
+	TclEmitOpcode(		INST_DUP,			envPtr);
 	TclEmitOpcode(		INST_LIST_LENGTH,		envPtr);
-	TclEmitOpcode(		INST_POP,			envPtr);
-	PushStringLiteral(envPtr, "");
-    } else {
-	TclEmitInstInt4(	INST_LIST_RANGE_IMM, idx1,	envPtr);
-	TclEmitInt4(		idx2,				envPtr);
+	TclEmitPush(TclAddLiteralObj(envPtr, tmpObj, NULL),	envPtr);
+	TclEmitOpcode(		INST_GT,			envPtr);
+	offset = CurrentOffset(envPtr);
+	TclEmitInstInt1(	INST_JUMP_TRUE1, 0,		envPtr);
+	TclEmitPush(TclAddLiteralObj(envPtr, Tcl_ObjPrintf(
+		"list doesn't contain element %d", idx1), NULL), envPtr);
+	CompileReturnInternal(envPtr, INST_RETURN_IMM, TCL_ERROR, 0,
+		Tcl_ObjPrintf("-errorcode {TCL OPERATION LREPLACE BADIDX}"));
+	TclStoreInt1AtPtr(CurrentOffset(envPtr) - offset,
+		envPtr->codeStart + offset + 1);
+	TclAdjustStackDepth(-1, envPtr);
+    }
+    TclEmitOpcode(		INST_DUP,			envPtr);
+    TclEmitInstInt4(		INST_LIST_RANGE_IMM, 0,		envPtr);
+    TclEmitInt4(			idx1 - 1,		envPtr);
+    TclEmitInstInt4(		INST_REVERSE, 2,		envPtr);
+    TclEmitInstInt4(		INST_LIST_RANGE_IMM, idx2 + 1,	envPtr);
+    TclEmitInt4(			INDEX_END,		envPtr);
+    TclEmitOpcode(		INST_LIST_CONCAT,		envPtr);
+    goto done;
+
+    /*
+     * Issue instructions to perform the operations relating to configurations
+     * that do real replacement. All arguments are pushed and assembled into a
+     * pair: the list of values to replace with, and the list to do the
+     * surgery on.
+     */
+
+  replaceAll:
+    TclEmitOpcode(		INST_LIST_LENGTH,		envPtr);
+    TclEmitOpcode(		INST_POP,			envPtr);
+    goto done;
+
+  replaceHead:
+    TclEmitInstInt4(		INST_LIST_RANGE_IMM, idx1,	envPtr);
+    TclEmitInt4(			idx2,			envPtr);
+    TclEmitOpcode(		INST_LIST_CONCAT,		envPtr);
+    goto done;
+
+  replaceTail:
+    TclEmitInstInt4(		INST_LIST_RANGE_IMM, idx1,	envPtr);
+    TclEmitInt4(			idx2,			envPtr);
+    TclEmitInstInt4(		INST_REVERSE, 2,		envPtr);
+    TclEmitOpcode(		INST_LIST_CONCAT,		envPtr);
+    goto done;
+
+  replaceRange:
+    if (tmpObj != NULL) {
+	TclEmitOpcode(		INST_DUP,			envPtr);
+	TclEmitOpcode(		INST_LIST_LENGTH,		envPtr);
+	TclEmitPush(TclAddLiteralObj(envPtr, tmpObj, NULL),	envPtr);
+	TclEmitOpcode(		INST_GT,			envPtr);
+	offset = CurrentOffset(envPtr);
+	TclEmitInstInt1(	INST_JUMP_TRUE1, 0,		envPtr);
+	TclEmitPush(TclAddLiteralObj(envPtr, Tcl_ObjPrintf(
+		"list doesn't contain element %d", idx1), NULL), envPtr);
+	CompileReturnInternal(envPtr, INST_RETURN_IMM, TCL_ERROR, 0,
+		Tcl_ObjPrintf("-errorcode {TCL OPERATION LREPLACE BADIDX}"));
+	TclStoreInt1AtPtr(CurrentOffset(envPtr) - offset,
+		envPtr->codeStart + offset + 1);
+	TclAdjustStackDepth(-1, envPtr);
+    }
+    TclEmitOpcode(		INST_DUP,			envPtr);
+    TclEmitInstInt4(		INST_LIST_RANGE_IMM, 0,		envPtr);
+    TclEmitInt4(			idx1 - 1,		envPtr);
+    TclEmitInstInt4(		INST_REVERSE, 2,		envPtr);
+    TclEmitInstInt4(		INST_LIST_RANGE_IMM, idx2 + 1,	envPtr);
+    TclEmitInt4(			INDEX_END,		envPtr);
+    TclEmitInstInt4(		INST_REVERSE, 3,		envPtr);
+    TclEmitOpcode(		INST_LIST_CONCAT,		envPtr);
+    TclEmitInstInt4(		INST_REVERSE, 2,		envPtr);
+    TclEmitOpcode(		INST_LIST_CONCAT,		envPtr);
+    goto done;
+
+    /*
+     * Clean up the allocated memory.
+     */
+
+  done:
+    if (tmpObj != NULL) {
+	Tcl_DecrRefCount(tmpObj);
     }
     return TCL_OK;
 }
@@ -1791,6 +1956,28 @@ TclCompileNamespaceCodeCmd(
 }
 
 int
+TclCompileNamespaceOriginCmd(
+    Tcl_Interp *interp,		/* Used for error reporting. */
+    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
+				 * created by Tcl_ParseCommand. */
+    Command *cmdPtr,		/* Points to defintion of command being
+				 * compiled. */
+    CompileEnv *envPtr)		/* Holds resulting instructions. */
+{
+    Tcl_Token *tokenPtr;
+    DefineLineInformation;	/* TIP #280 */
+
+    if (parsePtr->numWords != 2) {
+	return TCL_ERROR;
+    }
+    tokenPtr = TokenAfter(parsePtr->tokenPtr);
+
+    CompileWord(envPtr,	tokenPtr,			interp, 1);
+    TclEmitOpcode(	INST_ORIGIN_COMMAND,		envPtr);
+    return TCL_OK;
+}
+
+int
 TclCompileNamespaceQualifiersCmd(
     Tcl_Interp *interp,		/* Used for error reporting. */
     Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
@@ -2852,6 +3039,66 @@ IndexTailVarIfKnown(
     return localIndex;
 }
 
+/*
+ * ----------------------------------------------------------------------
+ *
+ * TclCompileObjectNextCmd, TclCompileObjectSelfCmd --
+ *
+ *	Compilations of the TclOO utility commands [next] and [self].
+ *
+ * ----------------------------------------------------------------------
+ */
+
+int
+TclCompileObjectNextCmd(
+    Tcl_Interp *interp,		/* Used for error reporting. */
+    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
+				 * created by Tcl_ParseCommand. */
+    Command *cmdPtr,		/* Points to defintion of command being
+				 * compiled. */
+    CompileEnv *envPtr)		/* Holds resulting instructions. */
+{
+    DefineLineInformation;	/* TIP #280 */
+    Tcl_Token *tokenPtr = parsePtr->tokenPtr;
+    int i;
+
+    if (parsePtr->numWords > 255) {
+	return TCL_ERROR;
+    }
+
+    for (i=0 ; i<parsePtr->numWords ; i++) {
+	CompileWord(envPtr, tokenPtr, interp, i);
+	tokenPtr = TokenAfter(tokenPtr);
+    }
+    TclEmitInstInt1(	INST_TCLOO_NEXT, i,		envPtr);
+    return TCL_OK;
+}
+
+int
+TclCompileObjectNextToCmd(
+    Tcl_Interp *interp,		/* Used for error reporting. */
+    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
+				 * created by Tcl_ParseCommand. */
+    Command *cmdPtr,		/* Points to defintion of command being
+				 * compiled. */
+    CompileEnv *envPtr)		/* Holds resulting instructions. */
+{
+    DefineLineInformation;	/* TIP #280 */
+    Tcl_Token *tokenPtr = parsePtr->tokenPtr;
+    int i;
+
+    if (parsePtr->numWords < 2 || parsePtr->numWords > 255) {
+	return TCL_ERROR;
+    }
+
+    for (i=0 ; i<parsePtr->numWords ; i++) {
+	CompileWord(envPtr, tokenPtr, interp, i);
+	tokenPtr = TokenAfter(tokenPtr);
+    }
+    TclEmitInstInt1(	INST_TCLOO_NEXT_CLASS, i,	envPtr);
+    return TCL_OK;
+}
+
 int
 TclCompileObjectSelfCmd(
     Tcl_Interp *interp,		/* Used for error reporting. */
diff --git a/generic/tclCompCmdsSZ.c b/generic/tclCompCmdsSZ.c
index 754238f..e6ec0a6 100644
--- a/generic/tclCompCmdsSZ.c
+++ b/generic/tclCompCmdsSZ.c
@@ -17,6 +17,7 @@
 
 #include "tclInt.h"
 #include "tclCompile.h"
+#include "tclStringTrim.h"
 
 /*
  * Prototypes for procedures defined later in this file:
@@ -101,6 +102,59 @@ const AuxDataType tclJumptableInfoType = {
     if ((idx)<256) {OP1(STORE_SCALAR1,(idx));} else {OP4(STORE_SCALAR4,(idx));}
 #define INVOKE(name) \
     TclEmitInvoke(envPtr,INST_##name)
+
+#define INDEX_END	(-2)
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * GetIndexFromToken --
+ *
+ *	Parse a token and get the encoded version of the index (as understood
+ *	by TEBC), assuming it is at all knowable at compile time. Only handles
+ *	indices that are integers or 'end' or 'end-integer'.
+ *
+ * Returns:
+ *	TCL_OK if parsing succeeded, and TCL_ERROR if it failed.
+ *
+ * Side effects:
+ *	Sets *index to the index value if successful.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static inline int
+GetIndexFromToken(
+    Tcl_Token *tokenPtr,
+    int *index)
+{
+    Tcl_Obj *tmpObj = Tcl_NewObj();
+    int result, idx;
+
+    if (!TclWordKnownAtCompileTime(tokenPtr, tmpObj)) {
+	Tcl_DecrRefCount(tmpObj);
+	return TCL_ERROR;
+    }
+
+    result = TclGetIntFromObj(NULL, tmpObj, &idx);
+    if (result == TCL_OK) {
+	if (idx < 0) {
+	    result = TCL_ERROR;
+	}
+    } else {
+	result = TclGetIntForIndexM(NULL, tmpObj, INDEX_END, &idx);
+	if (result == TCL_OK && idx > INDEX_END) {
+	    result = TCL_ERROR;
+	}
+    }
+    Tcl_DecrRefCount(tmpObj);
+
+    if (result == TCL_OK) {
+	*index = idx;
+    }
+
+    return result;
+}
 
 /*
  *----------------------------------------------------------------------
@@ -371,6 +425,284 @@ TclCompileStringIndexCmd(
 }
 
 int
+TclCompileStringIsCmd(
+    Tcl_Interp *interp,		/* Used for error reporting. */
+    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
+				 * created by Tcl_ParseCommand. */
+    Command *cmdPtr,		/* Points to defintion of command being
+				 * compiled. */
+    CompileEnv *envPtr)		/* Holds resulting instructions. */
+{
+    DefineLineInformation;	/* TIP #280 */
+    Tcl_Token *tokenPtr = TokenAfter(parsePtr->tokenPtr);
+    static const char *const isClasses[] = {
+	"alnum",	"alpha",	"ascii",	"control",
+	"boolean",	"digit",	"double",	"entier",
+	"false",	"graph",	"integer",	"list",
+	"lower",	"print",	"punct",	"space",
+	"true",		"upper",	"wideinteger",	"wordchar",
+	"xdigit",	NULL
+    };
+    enum isClasses {
+	STR_IS_ALNUM,	STR_IS_ALPHA,	STR_IS_ASCII,	STR_IS_CONTROL,
+	STR_IS_BOOL,	STR_IS_DIGIT,	STR_IS_DOUBLE,	STR_IS_ENTIER,
+	STR_IS_FALSE,	STR_IS_GRAPH,	STR_IS_INT,	STR_IS_LIST,
+	STR_IS_LOWER,	STR_IS_PRINT,	STR_IS_PUNCT,	STR_IS_SPACE,
+	STR_IS_TRUE,	STR_IS_UPPER,	STR_IS_WIDE,	STR_IS_WORD,
+	STR_IS_XDIGIT
+    };
+    int t, range, allowEmpty = 0, end;
+    InstStringClassType strClassType;
+    Tcl_Obj *isClass;
+
+    if (parsePtr->numWords < 3 || parsePtr->numWords > 6) {
+	return TCL_ERROR;
+    }
+    isClass = Tcl_NewObj();
+    if (!TclWordKnownAtCompileTime(tokenPtr, isClass)) {
+	Tcl_DecrRefCount(isClass);
+	return TCL_ERROR;
+    } else if (Tcl_GetIndexFromObj(interp, isClass, isClasses, "class", 0,
+	    &t) != TCL_OK) {
+	Tcl_DecrRefCount(isClass);
+	TclCompileSyntaxError(interp, envPtr);
+	return TCL_OK;
+    }
+    Tcl_DecrRefCount(isClass);
+
+#define GotLiteral(tokenPtr, word) \
+    ((tokenPtr)->type == TCL_TOKEN_SIMPLE_WORD &&			\
+     (tokenPtr)[1].size > 1 &&						\
+     (tokenPtr)[1].start[0] == word[0] &&				\
+     strncmp((tokenPtr)[1].start, (word), (tokenPtr)[1].size) == 0)
+
+    /*
+     * Cannot handle the -failindex option at all, and that's the only legal
+     * way to have more than 4 arguments.
+     */
+
+    if (parsePtr->numWords != 3 && parsePtr->numWords != 4) {
+	return TCL_ERROR;
+    }
+
+    tokenPtr = TokenAfter(tokenPtr);
+    if (parsePtr->numWords == 3) {
+	allowEmpty = 1;
+    } else {
+	if (!GotLiteral(tokenPtr, "-strict")) {
+	    return TCL_ERROR;
+	}
+	tokenPtr = TokenAfter(tokenPtr);
+    }
+#undef GotLiteral
+
+    /*
+     * Compile the code. There are several main classes of check here.
+     *	1. Character classes
+     *	2. Booleans
+     *	3. Integers
+     *	4. Floats
+     *	5. Lists
+     */
+
+    CompileWord(envPtr, tokenPtr, interp, parsePtr->numWords-1);
+
+    switch ((enum isClasses) t) {
+    case STR_IS_ALNUM:
+	strClassType = STR_CLASS_ALNUM;
+	goto compileStrClass;
+    case STR_IS_ALPHA:
+	strClassType = STR_CLASS_ALPHA;
+	goto compileStrClass;
+    case STR_IS_ASCII:
+	strClassType = STR_CLASS_ASCII;
+	goto compileStrClass;
+    case STR_IS_CONTROL:
+	strClassType = STR_CLASS_CONTROL;
+	goto compileStrClass;
+    case STR_IS_DIGIT:
+	strClassType = STR_CLASS_DIGIT;
+	goto compileStrClass;
+    case STR_IS_GRAPH:
+	strClassType = STR_CLASS_GRAPH;
+	goto compileStrClass;
+    case STR_IS_LOWER:
+	strClassType = STR_CLASS_LOWER;
+	goto compileStrClass;
+    case STR_IS_PRINT:
+	strClassType = STR_CLASS_PRINT;
+	goto compileStrClass;
+    case STR_IS_PUNCT:
+	strClassType = STR_CLASS_PUNCT;
+	goto compileStrClass;
+    case STR_IS_SPACE:
+	strClassType = STR_CLASS_SPACE;
+	goto compileStrClass;
+    case STR_IS_UPPER:
+	strClassType = STR_CLASS_UPPER;
+	goto compileStrClass;
+    case STR_IS_WORD:
+	strClassType = STR_CLASS_WORD;
+	goto compileStrClass;
+    case STR_IS_XDIGIT:
+	strClassType = STR_CLASS_XDIGIT;
+    compileStrClass:
+	if (allowEmpty) {
+	    OP1(	STR_CLASS, strClassType);
+	} else {
+	    int over, over2;
+
+	    OP(		DUP);
+	    OP1(	STR_CLASS, strClassType);
+	    JUMP1(	JUMP_TRUE, over);
+	    OP(		POP);
+	    PUSH(	"0");
+	    JUMP1(	JUMP, over2);
+	    FIXJUMP1(over);
+	    PUSH(	"");
+	    OP(		STR_NEQ);
+	    FIXJUMP1(over2);
+	}
+	return TCL_OK;
+
+    case STR_IS_BOOL:
+    case STR_IS_FALSE:
+    case STR_IS_TRUE:
+	OP(		TRY_CVT_TO_BOOLEAN);
+	switch (t) {
+	    int over, over2;
+
+	case STR_IS_BOOL:
+	    if (allowEmpty) {
+		JUMP1(	JUMP_TRUE, over);
+		PUSH(	"");
+		OP(	STR_EQ);
+		JUMP1(	JUMP, over2);
+		FIXJUMP1(over);
+		OP(	POP);
+		PUSH(	"1");
+		FIXJUMP1(over2);
+	    } else {
+		OP4(	REVERSE, 2);
+		OP(	POP);
+	    }
+	    return TCL_OK;
+	case STR_IS_TRUE:
+	    JUMP1(	JUMP_TRUE, over);
+	    if (allowEmpty) {
+		PUSH(	"");
+		OP(	STR_EQ);
+	    } else {
+		OP(	POP);
+		PUSH(	"0");
+	    }
+	    FIXJUMP1(	over);
+	    OP(		LNOT);
+	    OP(		LNOT);
+	    return TCL_OK;
+	case STR_IS_FALSE:
+	    JUMP1(	JUMP_TRUE, over);
+	    if (allowEmpty) {
+		PUSH(	"");
+		OP(	STR_NEQ);
+	    } else {
+		OP(	POP);
+		PUSH(	"1");
+	    }
+	    FIXJUMP1(	over);
+	    OP(		LNOT);
+	    return TCL_OK;
+	}
+
+    case STR_IS_DOUBLE: {
+	int satisfied, isEmpty;
+
+	if (allowEmpty) {
+	    OP(		DUP);
+	    PUSH(	"");
+	    OP(		STR_EQ);
+	    JUMP1(	JUMP_TRUE, isEmpty);
+	    OP(		NUM_TYPE);
+	    JUMP1(	JUMP_TRUE, satisfied);
+	    PUSH(	"0");
+	    JUMP1(	JUMP, end);
+	    FIXJUMP1(	isEmpty);
+	    OP(		POP);
+	    FIXJUMP1(	satisfied);
+	} else {
+	    OP(		NUM_TYPE);
+	    JUMP1(	JUMP_TRUE, satisfied);
+	    PUSH(	"0");
+	    JUMP1(	JUMP, end);
+	    TclAdjustStackDepth(-1, envPtr);
+	    FIXJUMP1(	satisfied);
+	}
+	PUSH(		"1");
+	FIXJUMP1(	end);
+	return TCL_OK;
+    }
+
+    case STR_IS_INT:
+    case STR_IS_WIDE:
+    case STR_IS_ENTIER:
+	if (allowEmpty) {
+	    int testNumType;
+
+	    OP(		DUP);
+	    OP(		NUM_TYPE);
+	    OP(		DUP);
+	    JUMP1(	JUMP_TRUE, testNumType);
+	    OP(		POP);
+	    PUSH(	"");
+	    OP(		STR_EQ);
+	    JUMP1(	JUMP, end);
+	    TclAdjustStackDepth(1, envPtr);
+	    FIXJUMP1(	testNumType);
+	    OP4(	REVERSE, 2);
+	    OP(		POP);
+	} else {
+	    OP(		NUM_TYPE);
+	    OP(		DUP);
+	    JUMP1(	JUMP_FALSE, end);
+	}
+
+	switch (t) {
+	case STR_IS_INT:
+	    PUSH(	"1");
+	    OP(		EQ);
+	    break;
+	case STR_IS_WIDE:
+	    PUSH(	"2");
+	    OP(		LE);
+	    break;
+	case STR_IS_ENTIER:
+	    PUSH(	"3");
+	    OP(		LE);
+	    break;
+	}
+	FIXJUMP1(	end);
+	return TCL_OK;
+
+    case STR_IS_LIST:
+	range = TclCreateExceptRange(CATCH_EXCEPTION_RANGE, envPtr);
+	OP4(		BEGIN_CATCH4, range);
+	ExceptionRangeStarts(envPtr, range);
+	OP(		DUP);
+	OP(		LIST_LENGTH);
+	OP(		POP);
+	ExceptionRangeEnds(envPtr, range);
+	ExceptionRangeTarget(envPtr, range, catchOffset);
+	OP(		POP);
+	OP(		PUSH_RETURN_CODE);
+	OP(		END_CATCH);
+	OP(		LNOT);
+	return TCL_OK;
+    }
+
+    return TclCompileBasicMin0ArgCmd(interp, parsePtr, cmdPtr, envPtr);
+}
+
+int
 TclCompileStringMatchCmd(
     Tcl_Interp *interp,		/* Used for error reporting. */
     Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
@@ -565,8 +897,7 @@ TclCompileStringRangeCmd(
 {
     DefineLineInformation;	/* TIP #280 */
     Tcl_Token *stringTokenPtr, *fromTokenPtr, *toTokenPtr;
-    Tcl_Obj *tmpObj;
-    int idx1, idx2, result;
+    int idx1, idx2;
 
     if (parsePtr->numWords != 4) {
 	return TCL_ERROR;
@@ -576,50 +907,13 @@ TclCompileStringRangeCmd(
     toTokenPtr = TokenAfter(fromTokenPtr);
 
     /*
-     * Parse the first index. Will only compile if it is constant and not an
-     * _integer_ less than zero (since we reserve negative indices here for
-     * end-relative indexing).
+     * Parse the two indices.
      */
 
-    tmpObj = Tcl_NewObj();
-    result = TCL_ERROR;
-    if (TclWordKnownAtCompileTime(fromTokenPtr, tmpObj)) {
-	if (TclGetIntFromObj(NULL, tmpObj, &idx1) == TCL_OK) {
-	    if (idx1 >= 0) {
-		result = TCL_OK;
-	    }
-	} else if (TclGetIntForIndexM(NULL, tmpObj, -2, &idx1) == TCL_OK) {
-	    if (idx1 <= -2) {
-		result = TCL_OK;
-	    }
-	}
-    }
-    TclDecrRefCount(tmpObj);
-    if (result != TCL_OK) {
+    if (GetIndexFromToken(fromTokenPtr, &idx1) != TCL_OK) {
 	goto nonConstantIndices;
     }
-
-    /*
-     * Parse the second index. Will only compile if it is constant and not an
-     * _integer_ less than zero (since we reserve negative indices here for
-     * end-relative indexing).
-     */
-
-    tmpObj = Tcl_NewObj();
-    result = TCL_ERROR;
-    if (TclWordKnownAtCompileTime(toTokenPtr, tmpObj)) {
-	if (TclGetIntFromObj(NULL, tmpObj, &idx2) == TCL_OK) {
-	    if (idx2 >= 0) {
-		result = TCL_OK;
-	    }
-	} else if (TclGetIntForIndexM(NULL, tmpObj, -2, &idx2) == TCL_OK) {
-	    if (idx2 <= -2) {
-		result = TCL_OK;
-	    }
-	}
-    }
-    TclDecrRefCount(tmpObj);
-    if (result != TCL_OK) {
+    if (GetIndexFromToken(toTokenPtr, &idx2) != TCL_OK) {
 	goto nonConstantIndices;
     }
 
@@ -642,6 +936,320 @@ TclCompileStringRangeCmd(
     OP(			STR_RANGE);
     return TCL_OK;
 }
+
+int
+TclCompileStringReplaceCmd(
+    Tcl_Interp *interp,		/* Tcl interpreter for context. */
+    Tcl_Parse *parsePtr,	/* Points to a parse structure for the
+				 * command. */
+    Command *cmdPtr,		/* Points to defintion of command being
+				 * compiled. */
+    CompileEnv *envPtr)		/* Holds the resulting instructions. */
+{
+    Tcl_Token *tokenPtr, *valueTokenPtr, *replacementTokenPtr = NULL;
+    DefineLineInformation;	/* TIP #280 */
+    int idx1, idx2;
+
+    if (parsePtr->numWords < 4 || parsePtr->numWords > 5) {
+	return TCL_ERROR;
+    }
+    valueTokenPtr = TokenAfter(parsePtr->tokenPtr);
+    if (parsePtr->numWords == 5) {
+	tokenPtr = TokenAfter(valueTokenPtr);
+	tokenPtr = TokenAfter(tokenPtr);
+	replacementTokenPtr = TokenAfter(tokenPtr);
+    }
+
+    /*
+     * Parse the indices. Will only compile special cases if both are
+     * constants and not an _integer_ less than zero (since we reserve
+     * negative indices here for end-relative indexing) or an end-based index
+     * greater than 'end' itself.
+     */
+
+    tokenPtr = TokenAfter(valueTokenPtr);
+    if (GetIndexFromToken(tokenPtr, &idx1) != TCL_OK) {
+	goto genericReplace;
+    }
+
+    tokenPtr = TokenAfter(tokenPtr);
+    if (GetIndexFromToken(tokenPtr, &idx2) != TCL_OK) {
+	goto genericReplace;
+    }
+
+    /*
+     * We handle these replacements specially: first character (where
+     * idx1=idx2=0) and last character (where idx1=idx2=INDEX_END). Anything
+     * else and the semantics get rather screwy.
+     */
+
+    if (idx1 == 0 && idx2 == 0) {
+	int notEq, end;
+
+	/*
+	 * Just working with the first character.
+	 */
+
+	CompileWord(envPtr, valueTokenPtr, interp, 1);
+	if (replacementTokenPtr == NULL) {
+	    /* Drop first */
+	    OP44(	STR_RANGE_IMM, 1, INDEX_END);
+	    return TCL_OK;
+	}
+	/* Replace first */
+	CompileWord(envPtr, replacementTokenPtr, interp, 4);
+	OP4(		OVER, 1);
+	PUSH(		"");
+	OP(		STR_EQ);
+	JUMP1(		JUMP_FALSE, notEq);
+	OP(		POP);
+	JUMP1(		JUMP, end);
+	FIXJUMP1(notEq);
+	TclAdjustStackDepth(1, envPtr);
+	OP4(		REVERSE, 2);
+	OP44(		STR_RANGE_IMM, 1, INDEX_END);
+	OP1(		STR_CONCAT1, 2);
+	FIXJUMP1(end);
+	return TCL_OK;
+
+    } else if (idx1 == INDEX_END && idx2 == INDEX_END) {
+	int notEq, end;
+
+	/*
+	 * Just working with the last character.
+	 */
+
+	CompileWord(envPtr, valueTokenPtr, interp, 1);
+	if (replacementTokenPtr == NULL) {
+	    /* Drop last */
+	    OP44(	STR_RANGE_IMM, 0, INDEX_END-1);
+	    return TCL_OK;
+	}
+	/* Replace last */
+	CompileWord(envPtr, replacementTokenPtr, interp, 4);
+	OP4(		OVER, 1);
+	PUSH(		"");
+	OP(		STR_EQ);
+	JUMP1(		JUMP_FALSE, notEq);
+	OP(		POP);
+	JUMP1(		JUMP, end);
+	FIXJUMP1(notEq);
+	TclAdjustStackDepth(1, envPtr);
+	OP4(		REVERSE, 2);
+	OP44(		STR_RANGE_IMM, 0, INDEX_END-1);
+	OP4(		REVERSE, 2);
+	OP1(		STR_CONCAT1, 2);
+	FIXJUMP1(end);
+	return TCL_OK;
+
+    } else {
+	/*
+	 * Need to process indices at runtime. This could be because the
+	 * indices are not constants, or because we need to resolve them to
+	 * absolute indices to work out if a replacement is going to happen.
+	 * In any case, to runtime it is.
+	 */
+
+    genericReplace:
+	CompileWord(envPtr, valueTokenPtr, interp, 1);
+	tokenPtr = TokenAfter(valueTokenPtr);
+	CompileWord(envPtr, tokenPtr, interp, 2);
+	tokenPtr = TokenAfter(tokenPtr);
+	CompileWord(envPtr, tokenPtr, interp, 3);
+	if (replacementTokenPtr != NULL) {
+	    CompileWord(envPtr, replacementTokenPtr, interp, 4);
+	} else {
+	    PUSH(	"");
+	}
+	OP(		STR_REPLACE);
+	return TCL_OK;
+    }
+}
+
+int
+TclCompileStringTrimLCmd(
+    Tcl_Interp *interp,		/* Used for error reporting. */
+    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
+				 * created by Tcl_ParseCommand. */
+    Command *cmdPtr,		/* Points to defintion of command being
+				 * compiled. */
+    CompileEnv *envPtr)		/* Holds resulting instructions. */
+{
+    DefineLineInformation;	/* TIP #280 */
+    Tcl_Token *tokenPtr;
+
+    if (parsePtr->numWords != 2 && parsePtr->numWords != 3) {
+	return TCL_ERROR;
+    }
+
+    tokenPtr = TokenAfter(parsePtr->tokenPtr);
+    CompileWord(envPtr, tokenPtr,			interp, 1);
+    if (parsePtr->numWords == 3) {
+	tokenPtr = TokenAfter(tokenPtr);
+	CompileWord(envPtr, tokenPtr,			interp, 2);
+    } else {
+	PushLiteral(envPtr, tclDefaultTrimSet, strlen(tclDefaultTrimSet));
+    }
+    OP(			STR_TRIM_LEFT);
+    return TCL_OK;
+}
+
+int
+TclCompileStringTrimRCmd(
+    Tcl_Interp *interp,		/* Used for error reporting. */
+    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
+				 * created by Tcl_ParseCommand. */
+    Command *cmdPtr,		/* Points to defintion of command being
+				 * compiled. */
+    CompileEnv *envPtr)		/* Holds resulting instructions. */
+{
+    DefineLineInformation;	/* TIP #280 */
+    Tcl_Token *tokenPtr;
+
+    if (parsePtr->numWords != 2 && parsePtr->numWords != 3) {
+	return TCL_ERROR;
+    }
+
+    tokenPtr = TokenAfter(parsePtr->tokenPtr);
+    CompileWord(envPtr, tokenPtr,			interp, 1);
+    if (parsePtr->numWords == 3) {
+	tokenPtr = TokenAfter(tokenPtr);
+	CompileWord(envPtr, tokenPtr,			interp, 2);
+    } else {
+	PushLiteral(envPtr, tclDefaultTrimSet, strlen(tclDefaultTrimSet));
+    }
+    OP(			STR_TRIM_RIGHT);
+    return TCL_OK;
+}
+
+int
+TclCompileStringTrimCmd(
+    Tcl_Interp *interp,		/* Used for error reporting. */
+    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
+				 * created by Tcl_ParseCommand. */
+    Command *cmdPtr,		/* Points to defintion of command being
+				 * compiled. */
+    CompileEnv *envPtr)		/* Holds resulting instructions. */
+{
+    DefineLineInformation;	/* TIP #280 */
+    Tcl_Token *tokenPtr;
+
+    if (parsePtr->numWords != 2 && parsePtr->numWords != 3) {
+	return TCL_ERROR;
+    }
+
+    tokenPtr = TokenAfter(parsePtr->tokenPtr);
+    CompileWord(envPtr, tokenPtr,			interp, 1);
+    if (parsePtr->numWords == 3) {
+	tokenPtr = TokenAfter(tokenPtr);
+	CompileWord(envPtr, tokenPtr,			interp, 2);
+    } else {
+	PushLiteral(envPtr, tclDefaultTrimSet, strlen(tclDefaultTrimSet));
+    }
+    OP(			STR_TRIM);
+    return TCL_OK;
+}
+
+int
+TclCompileStringToUpperCmd(
+    Tcl_Interp *interp,		/* Used for error reporting. */
+    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
+				 * created by Tcl_ParseCommand. */
+    Command *cmdPtr,		/* Points to defintion of command being
+				 * compiled. */
+    CompileEnv *envPtr)		/* Holds resulting instructions. */
+{
+    DefineLineInformation;	/* TIP #280 */
+    Tcl_Token *tokenPtr;
+
+    if (parsePtr->numWords != 2) {
+	return TclCompileBasic1To3ArgCmd(interp, parsePtr, cmdPtr, envPtr);
+    }
+
+    tokenPtr = TokenAfter(parsePtr->tokenPtr);
+    CompileWord(envPtr, tokenPtr,			interp, 1);
+    OP(			STR_UPPER);
+    return TCL_OK;
+}
+
+int
+TclCompileStringToLowerCmd(
+    Tcl_Interp *interp,		/* Used for error reporting. */
+    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
+				 * created by Tcl_ParseCommand. */
+    Command *cmdPtr,		/* Points to defintion of command being
+				 * compiled. */
+    CompileEnv *envPtr)		/* Holds resulting instructions. */
+{
+    DefineLineInformation;	/* TIP #280 */
+    Tcl_Token *tokenPtr;
+
+    if (parsePtr->numWords != 2) {
+	return TclCompileBasic1To3ArgCmd(interp, parsePtr, cmdPtr, envPtr);
+    }
+
+    tokenPtr = TokenAfter(parsePtr->tokenPtr);
+    CompileWord(envPtr, tokenPtr,			interp, 1);
+    OP(			STR_LOWER);
+    return TCL_OK;
+}
+
+int
+TclCompileStringToTitleCmd(
+    Tcl_Interp *interp,		/* Used for error reporting. */
+    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
+				 * created by Tcl_ParseCommand. */
+    Command *cmdPtr,		/* Points to defintion of command being
+				 * compiled. */
+    CompileEnv *envPtr)		/* Holds resulting instructions. */
+{
+    DefineLineInformation;	/* TIP #280 */
+    Tcl_Token *tokenPtr;
+
+    if (parsePtr->numWords != 2) {
+	return TclCompileBasic1To3ArgCmd(interp, parsePtr, cmdPtr, envPtr);
+    }
+
+    tokenPtr = TokenAfter(parsePtr->tokenPtr);
+    CompileWord(envPtr, tokenPtr,			interp, 1);
+    OP(			STR_TITLE);
+    return TCL_OK;
+}
+
+/*
+ * Support definitions for the [string is] compilation.
+ */
+
+static int
+UniCharIsAscii(
+    int character)
+{
+    return (character >= 0) && (character < 0x80);
+}
+
+static int
+UniCharIsHexDigit(
+    int character)
+{
+    return (character >= 0) && (character < 0x80) && isxdigit(character);
+}
+
+StringClassDesc const tclStringClassTable[] = {
+    {"alnum",	Tcl_UniCharIsAlnum},
+    {"alpha",	Tcl_UniCharIsAlpha},
+    {"ascii",	UniCharIsAscii},
+    {"control", Tcl_UniCharIsControl},
+    {"digit",	Tcl_UniCharIsDigit},
+    {"graph",	Tcl_UniCharIsGraph},
+    {"lower",	Tcl_UniCharIsLower},
+    {"print",	Tcl_UniCharIsPrint},
+    {"punct",	Tcl_UniCharIsPunct},
+    {"space",	Tcl_UniCharIsSpace},
+    {"upper",	Tcl_UniCharIsUpper},
+    {"word",	Tcl_UniCharIsWordChar},
+    {"xdigit",	UniCharIsHexDigit},
+    {NULL,	NULL}
+};
 
 /*
  *----------------------------------------------------------------------
@@ -752,7 +1360,7 @@ TclSubstCompile(
     /*
      * Tricky point! If the first token does not result in a *guaranteed* push
      * of a Tcl_Obj on the stack, we must push an empty object. Otherwise it
-     * is possible to get to an INST_CONCAT1 or INST_DONE without enough
+     * is possible to get to an INST_STR_CONCAT1 or INST_DONE without enough
      * values on the stack, resulting in a crash. Thanks to Joe Mistachkin for
      * identifying a script that could trigger this case.
      */
@@ -817,11 +1425,11 @@ TclSubstCompile(
 	}
 
 	while (count > 255) {
-	    OP1(		CONCAT1, 255);
+	    OP1(		STR_CONCAT1, 255);
 	    count -= 254;
 	}
 	if (count > 1) {
-	    OP1(		CONCAT1, count);
+	    OP1(		STR_CONCAT1, count);
 	    count = 1;
 	}
 
@@ -941,7 +1549,7 @@ TclSubstCompile(
 		    (int) (CurrentOffset(envPtr) - okFixup.codeOffset));
 	}
 	if (count > 1) {
-	    OP1(CONCAT1, count);
+	    OP1(STR_CONCAT1, count);
 	    count = 1;
 	}
 
@@ -954,11 +1562,11 @@ TclSubstCompile(
     }
 
     while (count > 255) {
-	OP1(	CONCAT1, 255);
+	OP1(	STR_CONCAT1, 255);
 	count -= 254;
     }
     if (count > 1) {
-	OP1(	CONCAT1, count);
+	OP1(	STR_CONCAT1, count);
     }
 
     Tcl_FreeParse(&parse);
@@ -3071,6 +3679,7 @@ TclCompileWhileCmd(
 	}
 	SetLineInformation(1);
 	TclCompileExprWords(interp, testTokenPtr, 1, envPtr);
+	TclClearNumConversion(envPtr);
 
 	jumpDist = CurrentOffset(envPtr) - bodyCodeOffset;
 	if (jumpDist > 127) {
@@ -3151,6 +3760,51 @@ TclCompileYieldCmd(
 /*
  *----------------------------------------------------------------------
  *
+ * TclCompileYieldToCmd --
+ *
+ *	Procedure called to compile the "yieldto" command.
+ *
+ * Results:
+ *	Returns TCL_OK for a successful compile. Returns TCL_ERROR to defer
+ *	evaluation to runtime.
+ *
+ * Side effects:
+ *	Instructions are added to envPtr to execute the "yieldto" command at
+ *	runtime.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+TclCompileYieldToCmd(
+    Tcl_Interp *interp,		/* Used for error reporting. */
+    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
+				 * created by Tcl_ParseCommand. */
+    Command *cmdPtr,		/* Points to defintion of command being
+				 * compiled. */
+    CompileEnv *envPtr)		/* Holds resulting instructions. */
+{
+    DefineLineInformation;	/* TIP #280 */
+    Tcl_Token *tokenPtr = TokenAfter(parsePtr->tokenPtr);
+    int i;
+
+    if (parsePtr->numWords < 2) {
+	return TCL_ERROR;
+    }
+
+    OP(		NS_CURRENT);
+    for (i = 1 ; i < parsePtr->numWords ; i++) {
+	CompileWord(envPtr, tokenPtr, interp, i);
+	tokenPtr = TokenAfter(tokenPtr);
+    }
+    OP4(	LIST, i);
+    OP(		YIELD_TO_INVOKE);
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
  * CompileUnaryOpCmd --
  *
  *	Utility routine to compile the unary operator commands.
diff --git a/generic/tclCompile.c b/generic/tclCompile.c
index 3c8e4ef..347e3f0 100644
--- a/generic/tclCompile.c
+++ b/generic/tclCompile.c
@@ -63,7 +63,7 @@ InstructionDesc const tclInstructionTable[] = {
 	/* Pop the topmost stack object */
     {"dup",		  1,   +1,         0,	{OPERAND_NONE}},
 	/* Duplicate the topmost stack object and push the result */
-    {"concat1",		  2,   INT_MIN,    1,	{OPERAND_UINT1}},
+    {"strcat",		  2,   INT_MIN,    1,	{OPERAND_UINT1}},
 	/* Concatenate the top op1 items and push result */
     {"invokeStk1",	  2,   INT_MIN,    1,	{OPERAND_UINT1}},
 	/* Invoke command named objv[0]; <objc,objv> = <op1,top op1> */
@@ -493,6 +493,7 @@ InstructionDesc const tclInstructionTable[] = {
 	 * qualified version, or produces the empty string if no such command
 	 * exists. Never generates errors.
 	 * Stack:  ... cmdName => ... fullCmdName */
+
     {"tclooSelf",	 1,	+1,	  0,	{OPERAND_NONE}},
 	/* Push the identity of the current TclOO object (i.e., the name of
 	 * its current public access command) on the stack. */
@@ -545,6 +546,110 @@ InstructionDesc const tclInstructionTable[] = {
 	/* Drops an element from the auxiliary stack, popping stack elements
 	 * until the matching stack depth is reached. */
 
+    /* New foreach implementation */
+    {"foreach_start",	 5,	+2,	  1,	{OPERAND_AUX4}},
+	/* Initialize execution of a foreach loop. Operand is aux data index
+	 * of the ForeachInfo structure for the foreach command. It pushes 2
+	 * elements which hold runtime params for foreach_step, they are later
+	 * dropped by foreach_end together with the value lists. NOTE that the
+	 * iterator-tracker and info reference must not be passed to bytecodes
+	 * that handle normal Tcl values. NOTE that this instruction jumps to
+	 * the foreach_step instruction paired with it; the stack info below
+	 * is only nominal.
+	 * Stack: ... listObjs... => ... listObjs... iterTracker info */
+    {"foreach_step",	 1,	 0,	  0,	{OPERAND_NONE}},
+	/* "Step" or begin next iteration of foreach loop. Assigns to foreach
+	 * iteration variables. May jump to straight after the foreach_start
+	 * that pushed the iterTracker and info values. MUST be followed
+	 * immediately by a foreach_end.
+	 * Stack: ... listObjs... iterTracker info =>
+	 *				... listObjs... iterTracker info */
+    {"foreach_end",	 1,	 0,	  0,	{OPERAND_NONE}},
+	/* Clean up a foreach loop by dropping the info value, the tracker
+	 * value and the lists that were being iterated over.
+	 * Stack: ... listObjs... iterTracker info => ... */
+    {"lmap_collect",	 1,	-1,	  0,	{OPERAND_NONE}},
+	/* Appends the value at the top of the stack to the list located on
+	 * the stack the "other side" of the foreach-related values.
+	 * Stack: ... collector listObjs... iterTracker info value =>
+	 *			... collector listObjs... iterTracker info */
+
+    {"strtrim",		 1,	-1,	  0,	{OPERAND_NONE}},
+	/* [string trim] core: removes the characters (designated by the value
+	 * at the top of the stack) from both ends of the string and pushes
+	 * the resulting string.
+	 * Stack: ... string charset => ... trimmedString */
+    {"strtrimLeft",	 1,	-1,	  0,	{OPERAND_NONE}},
+	/* [string trimleft] core: removes the characters (designated by the
+	 * value at the top of the stack) from the left of the string and
+	 * pushes the resulting string.
+	 * Stack: ... string charset => ... trimmedString */
+    {"strtrimRight",	 1,	-1,	  0,	{OPERAND_NONE}},
+	/* [string trimright] core: removes the characters (designated by the
+	 * value at the top of the stack) from the right of the string and
+	 * pushes the resulting string.
+	 * Stack: ... string charset => ... trimmedString */
+
+    {"concatStk",	 5,	INT_MIN,  1,	{OPERAND_UINT4}},
+	/* Wrapper round Tcl_ConcatObj(), used for [concat] and [eval]. opnd
+	 * is number of values to concatenate.
+	 * Operation:	push concat(stk1 stk2 ... stktop) */
+
+    {"strcaseUpper",	 1,	0,	  0,	{OPERAND_NONE}},
+	/* [string toupper] core: converts whole string to upper case using
+	 * the default (extended "C" locale) rules.
+	 * Stack: ... string => ... newString */
+    {"strcaseLower",	 1,	0,	  0,	{OPERAND_NONE}},
+	/* [string tolower] core: converts whole string to upper case using
+	 * the default (extended "C" locale) rules.
+	 * Stack: ... string => ... newString */
+    {"strcaseTitle",	 1,	0,	  0,	{OPERAND_NONE}},
+	/* [string totitle] core: converts whole string to upper case using
+	 * the default (extended "C" locale) rules.
+	 * Stack: ... string => ... newString */
+    {"strreplace",	 1,	-3,	  0,	{OPERAND_NONE}},
+	/* [string replace] core: replaces a non-empty range of one string
+	 * with the contents of another.
+	 * Stack: ... string fromIdx toIdx replacement => ... newString */
+
+    {"originCmd",	 1,	0,	  0,	{OPERAND_NONE}},
+	/* Reports which command was the origin (via namespace import chain)
+	 * of the command named on the top of the stack.
+	 * Stack:  ... cmdName => ... fullOriginalCmdName */
+
+    {"tclooNext",	 2,	INT_MIN,  1,	{OPERAND_UINT1}},
+	/* Call the next item on the TclOO call chain, passing opnd arguments
+	 * (min 1, max 255, *includes* "next").  The result of the invoked
+	 * method implementation will be pushed on the stack in place of the
+	 * arguments (similar to invokeStk).
+	 * Stack:  ... "next" arg2 arg3 -- argN => ... result */
+    {"tclooNextClass",	 2,	INT_MIN,  1,	{OPERAND_UINT1}},
+	/* Call the following item on the TclOO call chain defined by class
+	 * className, passing opnd arguments (min 2, max 255, *includes*
+	 * "nextto" and the class name). The result of the invoked method
+	 * implementation will be pushed on the stack in place of the
+	 * arguments (similar to invokeStk).
+	 * Stack:  ... "nextto" className arg3 arg4 -- argN => ... result */
+
+    {"yieldToInvoke",	 1,	0,	  0,	{OPERAND_NONE}},
+	/* Makes the current coroutine yield the value at the top of the
+	 * stack, invoking the given command/args with resolution in the given
+	 * namespace (all packed into a list), and places the list of values
+	 * that are the response back on top of the stack when it resumes.
+	 * Stack:  ... [list ns cmd arg1 ... argN] => ... resumeList */
+
+    {"numericType",	 1,	0,	  0,	{OPERAND_NONE}},
+	/* Pushes the numeric type code of the word at the top of the stack.
+	 * Stack:  ... value => ... typeCode */
+    {"tryCvtToBoolean",	 1,	+1,	  0,	{OPERAND_NONE}},
+	/* Try converting stktop to boolean if possible. No errors.
+	 * Stack:  ... value => ... value isStrictBool */
+    {"strclass",	 2,	0,	  1,	{OPERAND_SCLS1}},
+	/* See if all the characters of the given string are a member of the
+	 * specified (by opnd) character class. Note that an empty string will
+	 * satisfy the class check (standard definition of "all").
+	 * Stack:  ... stringValue => ... boolean */
+
     {NULL, 0, 0, 0, {OPERAND_NONE}}
 };
 
@@ -754,7 +859,9 @@ TclSetByteCodeFromAny(
      * instruction generator boundaries.
      */
 
-    TclOptimizeBytecode(&compEnv);
+    if (iPtr->extra.optimizer) {
+	(iPtr->extra.optimizer)(&compEnv);
+    }
 
     /*
      * Invoke the compilation hook procedure if one exists.
@@ -1709,7 +1816,7 @@ TclCompileInvocation(
     int numWords,
     CompileEnv *envPtr)
 {
-    int wordIdx = 0;
+    int wordIdx = 0, depth = TclGetStackDepth(envPtr);
     DefineLineInformation;
 
     if (cmdObj) {
@@ -1742,6 +1849,7 @@ TclCompileInvocation(
     } else {
 	TclEmitInvoke(envPtr, INST_INVOKE_STK4, wordIdx);
     }
+    TclCheckStackDepth(depth+1, envPtr);
 }
 
 static void
@@ -1754,7 +1862,8 @@ CompileExpanded(
 {
     int wordIdx = 0;
     DefineLineInformation;
-
+    int depth = TclGetStackDepth(envPtr);
+    
     StartExpanding(envPtr);
     if (cmdObj) {
 	CompileCmdLiteral(interp, cmdObj, envPtr);
@@ -1800,6 +1909,7 @@ CompileExpanded(
      */
 
     TclEmitInvoke(envPtr, INST_INVOKE_EXPANDED, wordIdx);
+    TclCheckStackDepth(depth+1, envPtr);
 }
 
 static int 
@@ -1811,6 +1921,7 @@ CompileCmdCompileProc(
 {
     int unwind = 0, incrOffset = -1;
     DefineLineInformation;
+    int depth = TclGetStackDepth(envPtr);
 
     /*
      * Emit of the INST_START_CMD instruction is controlled by the value of
@@ -1858,6 +1969,7 @@ CompileCmdCompileProc(
 		TclStoreInt4AtPtr(envPtr->codeNext - startPtr, startPtr + 1);
 	    }
 	}
+	TclCheckStackDepth(depth+1, envPtr);
 	return TCL_OK;
     }
 
@@ -1900,7 +2012,8 @@ CompileCommandTokens(
     int *clNext = envPtr->clNext;
     int cmdIdx = envPtr->numCommands;
     int startCodeOffset = envPtr->codeNext - envPtr->codeStart;
-
+    int depth = TclGetStackDepth(envPtr);
+    
     assert (parsePtr->numWords > 0);
 
     /* Pre-Compile */
@@ -1991,6 +2104,7 @@ CompileCommandTokens(
     eclPtr->loc[wlineat].line = wlines;
     eclPtr->loc[wlineat].next = NULL;
 
+    TclCheckStackDepth(depth, envPtr);
     return cmdIdx;
 }
 
@@ -2010,6 +2124,7 @@ TclCompileScript(
 				 * Initial value of -1 indicates this routine
 				 * has not yet generated any bytecode. */
     const char *p = script;	/* Where we are in our compile. */
+    int depth = TclGetStackDepth(envPtr);
 
     if (envPtr->iPtr == NULL) {
 	Tcl_Panic("TclCompileScript() called on uninitialized CompileEnv");
@@ -2121,6 +2236,7 @@ TclCompileScript(
 	envPtr->codeNext--;
 	envPtr->currStackDepth++;
     }
+    TclCheckStackDepth(depth+1, envPtr);
 }
 
 /*
@@ -2231,6 +2347,7 @@ TclCompileTokens(
 #define NUM_STATIC_POS 20
     int isLiteral, maxNumCL, numCL;
     int *clPosition = NULL;
+    int depth = TclGetStackDepth(envPtr);
 
     /*
      * For the handling of continuation lines in literals we first check if
@@ -2384,11 +2501,11 @@ TclCompileTokens(
      */
 
     while (numObjsToConcat > 255) {
-	TclEmitInstInt1(INST_CONCAT1, 255, envPtr);
+	TclEmitInstInt1(INST_STR_CONCAT1, 255, envPtr);
 	numObjsToConcat -= 254;	/* concat pushes 1 obj, the result */
     }
     if (numObjsToConcat > 1) {
-	TclEmitInstInt1(INST_CONCAT1, numObjsToConcat, envPtr);
+	TclEmitInstInt1(INST_STR_CONCAT1, numObjsToConcat, envPtr);
     }
 
     /*
@@ -2408,6 +2525,7 @@ TclCompileTokens(
     if (maxNumCL) {
 	ckfree(clPosition);
     }
+    TclCheckStackDepth(depth+1, envPtr);
 }
 
 /*
@@ -2519,11 +2637,11 @@ TclCompileExprWords(
     }
     concatItems = 2*numWords - 1;
     while (concatItems > 255) {
-	TclEmitInstInt1(INST_CONCAT1, 255, envPtr);
+	TclEmitInstInt1(INST_STR_CONCAT1, 255, envPtr);
 	concatItems -= 254;
     }
     if (concatItems > 1) {
-	TclEmitInstInt1(INST_CONCAT1, concatItems, envPtr);
+	TclEmitInstInt1(INST_STR_CONCAT1, concatItems, envPtr);
     }
     TclEmitOpcode(INST_EXPR_STK, envPtr);
 }
@@ -3923,7 +4041,8 @@ TclEmitInvoke(
     ExceptionAux *auxBreakPtr, *auxContinuePtr;
     int arg1, arg2, wordCount = 0, expandCount = 0;
     int loopRange = 0, breakRange = 0, continueRange = 0;
-
+    int cleanup, depth = TclGetStackDepth(envPtr);
+    
     /*
      * Parse the arguments.
      */
@@ -3931,30 +4050,31 @@ TclEmitInvoke(
     va_start(argList, opcode);
     switch (opcode) {
     case INST_INVOKE_STK1:
-	wordCount = arg1 = va_arg(argList, int);
+	wordCount = arg1 = cleanup = va_arg(argList, int);
 	arg2 = 0;
 	break;
     case INST_INVOKE_STK4:
-	wordCount = arg1 = va_arg(argList, int);
+	wordCount = arg1 = cleanup = va_arg(argList, int);
 	arg2 = 0;
 	break;
     case INST_INVOKE_REPLACE:
 	arg1 = va_arg(argList, int);
 	arg2 = va_arg(argList, int);
 	wordCount = arg1 + arg2 - 1;
+	cleanup = arg1 + 1;
 	break;
     default:
 	Tcl_Panic("unexpected opcode");
     case INST_EVAL_STK:
-	wordCount = 1;
+	wordCount = cleanup = 1;
 	arg1 = arg2 = 0;
 	break;
     case INST_RETURN_STK:
-	wordCount = 2;
+	wordCount = cleanup = 2;
 	arg1 = arg2 = 0;
 	break;
     case INST_INVOKE_EXPANDED:
-	wordCount = arg1 = va_arg(argList, int);
+	wordCount = arg1 = cleanup = va_arg(argList, int);
 	arg2 = 0;
 	expandCount = 1;
 	break;
@@ -4057,6 +4177,7 @@ TclEmitInvoke(
 	    ExceptionRangeTarget(envPtr, loopRange, breakOffset);
 	    TclCleanupStackForBreakContinue(envPtr, auxBreakPtr);
 	    TclAddLoopBreakFixup(envPtr, auxBreakPtr);
+	    TclAdjustStackDepth(1, envPtr);
 
 	    envPtr->currStackDepth = savedStackDepth;
 	    envPtr->expandCount = savedExpandCount;
@@ -4068,6 +4189,7 @@ TclEmitInvoke(
 	    ExceptionRangeTarget(envPtr, loopRange, continueOffset);
 	    TclCleanupStackForBreakContinue(envPtr, auxContinuePtr);
 	    TclAddLoopContinueFixup(envPtr, auxContinuePtr);
+	    TclAdjustStackDepth(1, envPtr);
 
 	    envPtr->currStackDepth = savedStackDepth;
 	    envPtr->expandCount = savedExpandCount;
@@ -4076,6 +4198,7 @@ TclEmitInvoke(
 	TclFinalizeLoopExceptionRange(envPtr, loopRange);
 	TclFixupForwardJumpToHere(envPtr, &nonTrapFixup, 127);
     }
+    TclCheckStackDepth(depth+1-cleanup, envPtr);
 }
 
 /*
@@ -4974,6 +5097,11 @@ FormatInstruction(
 	    }
 	    Tcl_AppendPrintfToObj(bufferObj, "%%v%u ", (unsigned) opnd);
 	    break;
+	case OPERAND_SCLS1:
+	    opnd = TclGetUInt1AtPtr(pc+numBytes); numBytes++;
+	    Tcl_AppendPrintfToObj(bufferObj, "%s ",
+		    tclStringClassTable[opnd].name);
+	    break;
 	case OPERAND_NONE:
 	default:
 	    break;
@@ -5190,7 +5318,7 @@ PrintSourceToObj(
     int maxChars)		/* Maximum number of chars to print. */
 {
     register const char *p;
-    register int i = 0;
+    register int i = 0, len;
 
     if (stringPtr == NULL) {
 	Tcl_AppendToObj(appendObj, "\"\"", -1);
@@ -5199,32 +5327,50 @@ PrintSourceToObj(
 
     Tcl_AppendToObj(appendObj, "\"", -1);
     p = stringPtr;
-    for (;  (*p != '\0') && (i < maxChars);  p++, i++) {
-	switch (*p) {
+    for (;  (*p != '\0') && (i < maxChars);  p+=len) {
+	Tcl_UniChar ch;
+
+	len = TclUtfToUniChar(p, &ch);
+	switch (ch) {
 	case '"':
 	    Tcl_AppendToObj(appendObj, "\\\"", -1);
+	    i += 2;
 	    continue;
 	case '\f':
 	    Tcl_AppendToObj(appendObj, "\\f", -1);
+	    i += 2;
 	    continue;
 	case '\n':
 	    Tcl_AppendToObj(appendObj, "\\n", -1);
+	    i += 2;
 	    continue;
 	case '\r':
 	    Tcl_AppendToObj(appendObj, "\\r", -1);
+	    i += 2;
 	    continue;
 	case '\t':
 	    Tcl_AppendToObj(appendObj, "\\t", -1);
+	    i += 2;
 	    continue;
 	case '\v':
 	    Tcl_AppendToObj(appendObj, "\\v", -1);
+	    i += 2;
 	    continue;
 	default:
-	    Tcl_AppendPrintfToObj(appendObj, "%c", *p);
+	    if (ch < 0x20 || ch >= 0x7f) {
+		Tcl_AppendPrintfToObj(appendObj, "\\u%04x", ch);
+		i += 6;
+	    } else {
+		Tcl_AppendPrintfToObj(appendObj, "%c", ch);
+		i++;
+	    }
 	    continue;
 	}
     }
     Tcl_AppendToObj(appendObj, "\"", -1);
+    if (*p != '\0') {
+	Tcl_AppendToObj(appendObj, "...", -1);
+    }
 }
 
 #ifdef TCL_COMPILE_STATS
diff --git a/generic/tclCompile.h b/generic/tclCompile.h
index a39e0f1..5665ca9 100644
--- a/generic/tclCompile.h
+++ b/generic/tclCompile.h
@@ -512,7 +512,7 @@ typedef struct ByteCode {
 #define INST_PUSH4			2
 #define INST_POP			3
 #define INST_DUP			4
-#define INST_CONCAT1			5
+#define INST_STR_CONCAT1		5
 #define INST_INVOKE_STK1		6
 #define INST_INVOKE_STK4		7
 #define INST_EVAL_STK			8
@@ -586,8 +586,8 @@ typedef struct ByteCode {
 #define INST_CONTINUE			66
 
 /* Opcodes 67 to 68 */
-#define INST_FOREACH_START4		67
-#define INST_FOREACH_STEP4		68
+#define INST_FOREACH_START4		67 /* DEPRECATED */
+#define INST_FOREACH_STEP4		68 /* DEPRECATED */
 
 /* Opcodes 69 to 72 */
 #define INST_BEGIN_CATCH4		69
@@ -751,6 +751,8 @@ typedef struct ByteCode {
 #define INST_INFO_LEVEL_NUM		152
 #define INST_INFO_LEVEL_ARGS		153
 #define INST_RESOLVE_COMMAND		154
+
+/* For compilation relating to TclOO */
 #define INST_TCLOO_SELF			155
 #define INST_TCLOO_CLASS		156
 #define INST_TCLOO_NS			157
@@ -768,8 +770,37 @@ typedef struct ByteCode {
 
 #define INST_EXPAND_DROP		165
 
+/* New foreach implementation */
+#define INST_FOREACH_START              166
+#define INST_FOREACH_STEP               167
+#define INST_FOREACH_END                168
+#define INST_LMAP_COLLECT               169
+
+/* For compilation of [string trim] and related */
+#define INST_STR_TRIM			170
+#define INST_STR_TRIM_LEFT		171
+#define INST_STR_TRIM_RIGHT		172
+
+#define INST_CONCAT_STK			173
+
+#define INST_STR_UPPER			174
+#define INST_STR_LOWER			175
+#define INST_STR_TITLE			176
+#define INST_STR_REPLACE		177
+
+#define INST_ORIGIN_COMMAND		178
+
+#define INST_TCLOO_NEXT			179
+#define INST_TCLOO_NEXT_CLASS		180
+
+#define INST_YIELD_TO_INVOKE		181
+
+#define INST_NUM_TYPE			182
+#define INST_TRY_CVT_TO_BOOLEAN		183
+#define INST_STR_CLASS			184
+
 /* The last opcode */
-#define LAST_INST_OPCODE		165
+#define LAST_INST_OPCODE		184
 
 /*
  * Table describing the Tcl bytecode instructions: their name (for displaying
@@ -794,8 +825,9 @@ typedef enum InstOperandType {
 				 * variable table. */
     OPERAND_LVT4,		/* Four byte unsigned index into the local
 				 * variable table. */
-    OPERAND_AUX4		/* Four byte unsigned index into the aux data
+    OPERAND_AUX4,		/* Four byte unsigned index into the aux data
 				 * table. */
+    OPERAND_SCLS1		/* Index into tclStringClassTable. */
 } InstOperandType;
 
 typedef struct InstructionDesc {
@@ -814,6 +846,40 @@ typedef struct InstructionDesc {
 MODULE_SCOPE InstructionDesc const tclInstructionTable[];
 
 /*
+ * Constants used by INST_STRING_CLASS to indicate character classes. These
+ * correspond closely by name with what [string is] can support, but there is
+ * no requirement to keep the values the same.
+ */
+
+typedef enum InstStringClassType {
+    STR_CLASS_ALNUM,		/* Unicode alphabet or digit characters. */
+    STR_CLASS_ALPHA,		/* Unicode alphabet characters. */
+    STR_CLASS_ASCII,		/* Characters in range U+000000..U+00007F. */
+    STR_CLASS_CONTROL,		/* Unicode control characters. */
+    STR_CLASS_DIGIT,		/* Unicode digit characters. */
+    STR_CLASS_GRAPH,		/* Unicode printing characters, excluding
+				 * space. */
+    STR_CLASS_LOWER,		/* Unicode lower-case alphabet characters. */
+    STR_CLASS_PRINT,		/* Unicode printing characters, including
+				 * spaces. */
+    STR_CLASS_PUNCT,		/* Unicode punctuation characters. */
+    STR_CLASS_SPACE,		/* Unicode space characters. */
+    STR_CLASS_UPPER,		/* Unicode upper-case alphabet characters. */
+    STR_CLASS_WORD,		/* Unicode word (alphabetic, digit, connector
+				 * punctuation) characters. */
+    STR_CLASS_XDIGIT		/* Characters that can be used as digits in
+				 * hexadecimal numbers ([0-9A-Fa-f]). */
+} InstStringClassType;
+
+typedef struct StringClassDesc {
+    const char *name;		/* Name of the class. */
+    int (*comparator)(int);	/* Function to test if a single unicode
+				 * character is a member of the class. */
+} StringClassDesc;
+
+MODULE_SCOPE StringClassDesc const tclStringClassTable[];
+
+/*
  * Compilation of some Tcl constructs such as if commands and the logical or
  * (||) and logical and (&&) operators in expressions requires the generation
  * of forward jumps. Since the PC target of these jumps isn't known when the
@@ -902,6 +968,7 @@ typedef struct ForeachInfo {
 } ForeachInfo;
 
 MODULE_SCOPE const AuxDataType tclForeachInfoType;
+MODULE_SCOPE const AuxDataType tclNewForeachInfoType;
 
 #define FOREACHINFO(envPtr, index) \
     ((ForeachInfo*)((envPtr)->auxDataArrayPtr[TclGetUInt4AtPtr(index)].clientData))
@@ -1056,7 +1123,7 @@ MODULE_SCOPE void	TclFinalizeLoopExceptionRange(CompileEnv *envPtr,
 MODULE_SCOPE char *	TclLiteralStats(LiteralTable *tablePtr);
 MODULE_SCOPE int	TclLog2(int value);
 #endif
-MODULE_SCOPE void	TclOptimizeBytecode(CompileEnv *envPtr);
+MODULE_SCOPE void	TclOptimizeBytecode(void *envPtr);
 #ifdef TCL_COMPILE_DEBUG
 MODULE_SCOPE void	TclPrintByteCodeObj(Tcl_Interp *interp,
 			    Tcl_Obj *objPtr);
@@ -1071,8 +1138,6 @@ MODULE_SCOPE void	TclPushVarName(Tcl_Interp *interp,
 			    Tcl_Token *varTokenPtr, CompileEnv *envPtr,
 			    int flags, int *localIndexPtr,
 			    int *isScalarPtr);
-MODULE_SCOPE int	TclRegisterLiteral(CompileEnv *envPtr,
-			    char *bytes, int length, int flags);
 MODULE_SCOPE void	TclReleaseLiteral(Tcl_Interp *interp, Tcl_Obj *objPtr);
 MODULE_SCOPE void	TclInvalidateCmdLiteral(Tcl_Interp *interp, 
 			    const char *name, Namespace *nsPtr);
@@ -1163,6 +1228,21 @@ MODULE_SCOPE Tcl_Obj	*TclNewInstNameObj(unsigned char inst);
 	(envPtr)->currStackDepth += (delta);				\
     } while (0)
 
+#define TclGetStackDepth(envPtr)		\
+    ((envPtr)->currStackDepth)
+
+#define TclSetStackDepth(depth, envPtr)		\
+    (envPtr)->currStackDepth = (depth)
+
+#define TclCheckStackDepth(depth, envPtr)				\
+    do {								\
+	int dd = (depth);						\
+	if (dd != (envPtr)->currStackDepth) {				\
+	    Tcl_Panic("bad stack depth computations: is %i, should be %i", \
+		    (envPtr)->currStackDepth, dd);		\
+	}								\
+    } while (0)
+
 /*
  * Macro used to update the stack requirements. It is called by the macros
  * TclEmitOpCode, TclEmitInst1 and TclEmitInst4.
@@ -1303,6 +1383,18 @@ MODULE_SCOPE Tcl_Obj	*TclNewInstNameObj(unsigned char inst);
     } while (0)
 
 /*
+ * If the expr compiler finished with TRY_CONVERT, macro to remove it when the
+ * job is done by the following instruction.
+ */
+
+#define TclClearNumConversion(envPtr) \
+    do {								\
+	if (*(envPtr->codeNext - 1) == INST_TRY_CVT_TO_NUMERIC) {	\
+	    envPtr->codeNext--;						\
+	}								\
+    } while (0)
+
+/*
  * Macros to update a (signed or unsigned) integer starting at a pointer. The
  * two variants depend on the number of bytes. The ANSI C "prototypes" for
  * these macros are:
diff --git a/generic/tclDecls.h b/generic/tclDecls.h
index 830c998..91c0add 100644
--- a/generic/tclDecls.h
+++ b/generic/tclDecls.h
@@ -63,7 +63,7 @@ EXTERN void		Tcl_DbCkfree(char *ptr, const char *file, int line);
 /* 8 */
 EXTERN char *		Tcl_DbCkrealloc(char *ptr, unsigned int size,
 				const char *file, int line);
-#if !defined(__WIN32__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(MAC_OSX_TCL) /* UNIX */
 /* 9 */
 EXTERN void		Tcl_CreateFileHandler(int fd, int mask,
 				Tcl_FileProc *proc, ClientData clientData);
@@ -73,7 +73,7 @@ EXTERN void		Tcl_CreateFileHandler(int fd, int mask,
 EXTERN void		Tcl_CreateFileHandler(int fd, int mask,
 				Tcl_FileProc *proc, ClientData clientData);
 #endif /* MACOSX */
-#if !defined(__WIN32__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(MAC_OSX_TCL) /* UNIX */
 /* 10 */
 EXTERN void		Tcl_DeleteFileHandler(int fd);
 #endif /* UNIX */
@@ -511,7 +511,7 @@ EXTERN Tcl_Interp *	Tcl_GetMaster(Tcl_Interp *interp);
 EXTERN const char *	Tcl_GetNameOfExecutable(void);
 /* 166 */
 EXTERN Tcl_Obj *	Tcl_GetObjResult(Tcl_Interp *interp);
-#if !defined(__WIN32__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(MAC_OSX_TCL) /* UNIX */
 /* 167 */
 EXTERN int		Tcl_GetOpenFile(Tcl_Interp *interp,
 				const char *chanID, int forWriting,
@@ -1835,19 +1835,19 @@ typedef struct TclStubs {
     char * (*tcl_DbCkalloc) (unsigned int size, const char *file, int line); /* 6 */
     void (*tcl_DbCkfree) (char *ptr, const char *file, int line); /* 7 */
     char * (*tcl_DbCkrealloc) (char *ptr, unsigned int size, const char *file, int line); /* 8 */
-#if !defined(__WIN32__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(MAC_OSX_TCL) /* UNIX */
     void (*tcl_CreateFileHandler) (int fd, int mask, Tcl_FileProc *proc, ClientData clientData); /* 9 */
 #endif /* UNIX */
-#if defined(__WIN32__) /* WIN */
+#if defined(_WIN32) /* WIN */
     void (*reserved9)(void);
 #endif /* WIN */
 #ifdef MAC_OSX_TCL /* MACOSX */
     void (*tcl_CreateFileHandler) (int fd, int mask, Tcl_FileProc *proc, ClientData clientData); /* 9 */
 #endif /* MACOSX */
-#if !defined(__WIN32__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(MAC_OSX_TCL) /* UNIX */
     void (*tcl_DeleteFileHandler) (int fd); /* 10 */
 #endif /* UNIX */
-#if defined(__WIN32__) /* WIN */
+#if defined(_WIN32) /* WIN */
     void (*reserved10)(void);
 #endif /* WIN */
 #ifdef MAC_OSX_TCL /* MACOSX */
@@ -2009,10 +2009,10 @@ typedef struct TclStubs {
     Tcl_Interp * (*tcl_GetMaster) (Tcl_Interp *interp); /* 164 */
     const char * (*tcl_GetNameOfExecutable) (void); /* 165 */
     Tcl_Obj * (*tcl_GetObjResult) (Tcl_Interp *interp); /* 166 */
-#if !defined(__WIN32__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(MAC_OSX_TCL) /* UNIX */
     int (*tcl_GetOpenFile) (Tcl_Interp *interp, const char *chanID, int forWriting, int checkUsage, ClientData *filePtr); /* 167 */
 #endif /* UNIX */
-#if defined(__WIN32__) /* WIN */
+#if defined(_WIN32) /* WIN */
     void (*reserved167)(void);
 #endif /* WIN */
 #ifdef MAC_OSX_TCL /* MACOSX */
@@ -2513,7 +2513,7 @@ extern const TclStubs *tclStubsPtr;
 	(tclStubsPtr->tcl_DbCkfree) /* 7 */
 #define Tcl_DbCkrealloc \
 	(tclStubsPtr->tcl_DbCkrealloc) /* 8 */
-#if !defined(__WIN32__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(MAC_OSX_TCL) /* UNIX */
 #define Tcl_CreateFileHandler \
 	(tclStubsPtr->tcl_CreateFileHandler) /* 9 */
 #endif /* UNIX */
@@ -2521,7 +2521,7 @@ extern const TclStubs *tclStubsPtr;
 #define Tcl_CreateFileHandler \
 	(tclStubsPtr->tcl_CreateFileHandler) /* 9 */
 #endif /* MACOSX */
-#if !defined(__WIN32__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(MAC_OSX_TCL) /* UNIX */
 #define Tcl_DeleteFileHandler \
 	(tclStubsPtr->tcl_DeleteFileHandler) /* 10 */
 #endif /* UNIX */
@@ -2841,7 +2841,7 @@ extern const TclStubs *tclStubsPtr;
 	(tclStubsPtr->tcl_GetNameOfExecutable) /* 165 */
 #define Tcl_GetObjResult \
 	(tclStubsPtr->tcl_GetObjResult) /* 166 */
-#if !defined(__WIN32__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(MAC_OSX_TCL) /* UNIX */
 #define Tcl_GetOpenFile \
 	(tclStubsPtr->tcl_GetOpenFile) /* 167 */
 #endif /* UNIX */
diff --git a/generic/tclEncoding.c b/generic/tclEncoding.c
index 2cc55d6..d246cb2 100644
--- a/generic/tclEncoding.c
+++ b/generic/tclEncoding.c
@@ -182,6 +182,7 @@ TCL_DECLARE_MUTEX(encodingMutex)
 
 static Tcl_Encoding defaultEncoding;
 static Tcl_Encoding systemEncoding;
+Tcl_Encoding tclIdentityEncoding;
 
 /*
  * The following variable is used in the sparse matrix code for a
@@ -567,7 +568,7 @@ TclInitEncodingSubsystem(void)
     type.freeProc	= NULL;
     type.nullSize	= 1;
     type.clientData	= NULL;
-    Tcl_CreateEncoding(&type);
+    tclIdentityEncoding = Tcl_CreateEncoding(&type);
 
     type.encodingName	= "utf-8";
     type.toUtfProc	= UtfExtToUtfIntProc;
@@ -651,6 +652,7 @@ TclFinalizeEncodingSubsystem(void)
     Tcl_MutexLock(&encodingMutex);
     encodingsInitialized = 0;
     FreeEncoding(systemEncoding);
+    FreeEncoding(tclIdentityEncoding);
 
     hPtr = Tcl_FirstHashEntry(&encodingTable, &search);
     while (hPtr != NULL) {
diff --git a/generic/tclEnv.c b/generic/tclEnv.c
index 6a21947..cd1a954 100644
--- a/generic/tclEnv.c
+++ b/generic/tclEnv.c
@@ -444,7 +444,7 @@ TclUnsetEnv(
      * that no = should be included, and Windows requires it.
      */
 
-#if defined(__WIN32__) || defined(__CYGWIN__)
+#if defined(_WIN32) || defined(__CYGWIN__)
     string = ckalloc(length + 2);
     memcpy(string, name, (size_t) length);
     string[length] = '=';
@@ -453,7 +453,7 @@ TclUnsetEnv(
     string = ckalloc(length + 1);
     memcpy(string, name, (size_t) length);
     string[length] = '\0';
-#endif /* WIN32 */
+#endif /* _WIN32 */
 
     Tcl_UtfToExternalDString(NULL, string, -1, &envString);
     string = ckrealloc(string, Tcl_DStringLength(&envString) + 1);
@@ -614,7 +614,8 @@ EnvTraceProc(
 	const char *value = TclGetEnv(name2, &valueString);
 
 	if (value == NULL) {
-	    return (char *) "no such variable";
+	    Tcl_UnsetVar2(interp, name1, name2, 0);
+	    return NULL;
 	}
 	Tcl_SetVar2(interp, name1, name2, value, 0);
 	Tcl_DStringFree(&valueString);
diff --git a/generic/tclExecute.c b/generic/tclExecute.c
index d3c1227..41730d3 100644
--- a/generic/tclExecute.c
+++ b/generic/tclExecute.c
@@ -174,29 +174,24 @@ static BuiltinFunc const tclBuiltinFuncTable[] = {
 typedef struct TEBCdata {
     ByteCode *codePtr;		/* Constant until the BC returns */
 				/* -----------------------------------------*/
-    const unsigned char *pc;	/* These fields are used on return TO this */
-    ptrdiff_t *catchTop;	/* this level: they record the state when a */
-    int cleanup;		/* new codePtr was received for NR */
-    Tcl_Obj *auxObjList;	/* execution. */
-    int checkInterp;
-    CmdFrame cmdFrame;
+    ptrdiff_t *catchTop;	/* These fields are used on return TO this */
+    Tcl_Obj *auxObjList;	/* this level: they record the state when a */
+    CmdFrame cmdFrame;		/* new codePtr was received for NR */
+                                /* execution. */
     void *stack[1];		/* Start of the actual combined catch and obj
 				 * stacks; the struct will be expanded as
 				 * necessary */
 } TEBCdata;
 
 #define TEBC_YIELD() \
-    do {								\
-	esPtr->tosPtr = tosPtr;						\
-	TD->pc = pc;							\
-	TD->cleanup = cleanup;						\
-	TclNRAddCallback(interp, TEBCresume, TD, INT2PTR(1), NULL, NULL); \
+    do {						\
+	esPtr->tosPtr = tosPtr;				\
+	TclNRAddCallback(interp, TEBCresume,		\
+		TD, pc, INT2PTR(cleanup), NULL);	\
     } while (0)
 
 #define TEBC_DATA_DIG() \
     do {					\
-	pc = TD->pc;				\
-	cleanup = TD->cleanup;			\
 	tosPtr = esPtr->tosPtr;			\
     } while (0)
 
@@ -320,6 +315,70 @@ VarHashCreateVar(
 	}							\
     } while (0)
 
+#ifndef TCL_COMPILE_DEBUG
+#define JUMP_PEEPHOLE_F(condition, pcAdjustment, cleanup) \
+    do {								\
+	pc += (pcAdjustment);						\
+	switch (*pc) {							\
+	case INST_JUMP_FALSE1:						\
+	    NEXT_INST_F(((condition)? 2 : TclGetInt1AtPtr(pc+1)), (cleanup), 0); \
+	case INST_JUMP_TRUE1:						\
+	    NEXT_INST_F(((condition)? TclGetInt1AtPtr(pc+1) : 2), (cleanup), 0); \
+	case INST_JUMP_FALSE4:						\
+	    NEXT_INST_F(((condition)? 5 : TclGetInt4AtPtr(pc+1)), (cleanup), 0); \
+	case INST_JUMP_TRUE4:						\
+	    NEXT_INST_F(((condition)? TclGetInt4AtPtr(pc+1) : 5), (cleanup), 0); \
+	default:							\
+	    if ((condition) < 0) {					\
+		TclNewIntObj(objResultPtr, -1);				\
+	    } else {							\
+		objResultPtr = TCONST((condition) > 0);			\
+	    }								\
+	    NEXT_INST_F(0, (cleanup), 1);				\
+	}								\
+    } while (0)
+#define JUMP_PEEPHOLE_V(condition, pcAdjustment, cleanup) \
+    do {								\
+	pc += (pcAdjustment);						\
+	switch (*pc) {							\
+	case INST_JUMP_FALSE1:						\
+	    NEXT_INST_V(((condition)? 2 : TclGetInt1AtPtr(pc+1)), (cleanup), 0); \
+	case INST_JUMP_TRUE1:						\
+	    NEXT_INST_V(((condition)? TclGetInt1AtPtr(pc+1) : 2), (cleanup), 0); \
+	case INST_JUMP_FALSE4:						\
+	    NEXT_INST_V(((condition)? 5 : TclGetInt4AtPtr(pc+1)), (cleanup), 0); \
+	case INST_JUMP_TRUE4:						\
+	    NEXT_INST_V(((condition)? TclGetInt4AtPtr(pc+1) : 5), (cleanup), 0); \
+	default:							\
+	    if ((condition) < 0) {					\
+		TclNewIntObj(objResultPtr, -1);				\
+	    } else {							\
+		objResultPtr = TCONST((condition) > 0);			\
+	    }								\
+	    NEXT_INST_V(0, (cleanup), 1);				\
+	}								\
+    } while (0)
+#else /* TCL_COMPILE_DEBUG */
+#define JUMP_PEEPHOLE_F(condition, pcAdjustment, cleanup) \
+    do{									\
+	if ((condition) < 0) {						\
+	    TclNewIntObj(objResultPtr, -1);				\
+	} else {							\
+	    objResultPtr = TCONST((condition) > 0);			\
+	}								\
+	NEXT_INST_F((pcAdjustment), (cleanup), 1);			\
+    } while (0)
+#define JUMP_PEEPHOLE_V(condition, pcAdjustment, cleanup) \
+    do{									\
+	if ((condition) < 0) {						\
+	    TclNewIntObj(objResultPtr, -1);				\
+	} else {							\
+	    objResultPtr = TCONST((condition) > 0);			\
+	}								\
+	NEXT_INST_V((pcAdjustment), (cleanup), 1);			\
+    } while (0)
+#endif
+
 /*
  * Macros used to cache often-referenced Tcl evaluation stack information
  * in local variables. Note that a DECACHE_STACK_INFO()-CACHE_STACK_INFO()
@@ -385,6 +444,8 @@ VarHashCreateVar(
 	printf a;			\
 	break;				\
     }
+#   define TRACE_ERROR(interp) \
+    TRACE_APPEND(("ERROR: %.30s\n", O2S(Tcl_GetObjResult(interp))));
 #   define TRACE_WITH_OBJ(a, objPtr) \
     while (traceInstructions) {					\
 	fprintf(stdout, "%2d: %2d (%u) %s ", iPtr->numLevels,	\
@@ -401,6 +462,7 @@ VarHashCreateVar(
 #else /* !TCL_COMPILE_DEBUG */
 #   define TRACE(a)
 #   define TRACE_APPEND(a)
+#   define TRACE_ERROR(interp)
 #   define TRACE_WITH_OBJ(a, objPtr)
 #   define O2S(objPtr)
 #endif /* TCL_COMPILE_DEBUG */
@@ -738,7 +800,8 @@ static Tcl_Obj **	StackAllocWords(Tcl_Interp *interp, int numWords);
 static Tcl_Obj **	StackReallocWords(Tcl_Interp *interp, int numWords);
 static Tcl_NRPostProc	CopyCallback;
 static Tcl_NRPostProc	ExprObjCallback;
-
+static Tcl_NRPostProc	FinalizeOONext;
+static Tcl_NRPostProc	FinalizeOONextFilter;
 static Tcl_NRPostProc   TEBCresume;
 
 /*
@@ -1934,6 +1997,41 @@ TclIncrObj(
 /*
  *----------------------------------------------------------------------
  *
+ * ArgumentBCEnter --
+ *
+ *	This is a helper for TclNRExecuteByteCode/TEBCresume that encapsulates
+ *	a code sequence that is fairly common in the code but *not* commonly
+ *	called.
+ *
+ * Results:
+ *	None
+ *
+ * Side effects:
+ *	May register information about the bytecode in the command frame.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+ArgumentBCEnter(
+    Tcl_Interp *interp,
+    ByteCode *codePtr,
+    TEBCdata *tdPtr,
+    const unsigned char *pc,
+    int objc,
+    Tcl_Obj **objv)
+{
+    int cmd;
+
+    if (GetSrcInfoForPc(pc, codePtr, NULL, NULL, &cmd)) {
+	TclArgumentBCEnter(interp, objv, objc, codePtr, &tdPtr->cmdFrame, cmd,
+		pc - codePtr->codeStart);
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
  * TclNRExecuteByteCode --
  *
  *	This procedure executes the instructions of a ByteCode structure. It
@@ -1966,10 +2064,6 @@ TclNRExecuteByteCode(
 		* sizeof(void *);
     int numWords = (size + sizeof(Tcl_Obj *) - 1) / sizeof(Tcl_Obj *);
 
-    if (iPtr->execEnvPtr->rewind) {
-	return TCL_ERROR;
-    }
-
     codePtr->refCount++;
 
     /*
@@ -1988,11 +2082,8 @@ TclNRExecuteByteCode(
     esPtr->tosPtr = initTosPtr;
 
     TD->codePtr     = codePtr;
-    TD->pc	    = codePtr->codeStart;
     TD->catchTop    = initCatchTop;
-    TD->cleanup     = 0;
     TD->auxObjList  = NULL;
-    TD->checkInterp = 0;
 
     /*
      * TIP #280: Initialize the frame. Do not push it yet: it will be pushed
@@ -2021,8 +2112,8 @@ TclNRExecuteByteCode(
      * Push the callback for bytecode execution
      */
 
-    TclNRAddCallback(interp, TEBCresume, TD, /*resume*/ INT2PTR(0),
-	    NULL, NULL);
+    TclNRAddCallback(interp, TEBCresume, TD, /* pc */ NULL,
+	    /* cleanup */ INT2PTR(0), NULL);
     return TCL_OK;
 }
 
@@ -2078,9 +2169,6 @@ TEBCresume(
 #define auxObjList	(TD->auxObjList)
 #define catchTop	(TD->catchTop)
 #define codePtr		(TD->codePtr)
-#define checkInterp	(TD->checkInterp)
-			/* Indicates when a check of interp readyness is
-			 * necessary. Set by CACHE_STACK_INFO() */
 
     /*
      * Globals: variables that store state, must remain valid at all times.
@@ -2088,7 +2176,8 @@ TEBCresume(
 
     Tcl_Obj **tosPtr;		/* Cached pointer to top of evaluation
 				 * stack. */
-    const unsigned char *pc;	/* The current program counter. */
+    const unsigned char *pc = data[1];
+                                /* The current program counter. */
     unsigned char inst;         /* The currently running instruction */
     
     /*
@@ -2096,8 +2185,10 @@ TEBCresume(
      * executing an instruction.
      */
 
-    int cleanup = 0;
+    int cleanup = PTR2INT(data[2]);
     Tcl_Obj *objResultPtr;
+    int checkInterp;            /* Indicates when a check of interp readyness
+				 * is necessary. Set by CACHE_STACK_INFO() */
 
     /*
      * Locals - variables that are used within opcodes or bounded sections of
@@ -2122,17 +2213,26 @@ TEBCresume(
     TEBC_DATA_DIG();
 
 #ifdef TCL_COMPILE_DEBUG
-    if (!data[1] && (tclTraceExec >= 2)) {
+    if (!pc && (tclTraceExec >= 2)) {
 	PrintByteCodeInfo(codePtr);
 	fprintf(stdout, "  Starting stack top=%d\n", (int) CURR_DEPTH);
 	fflush(stdout);
     }
 #endif
 
-    if (data[1] /* resume from invocation */) {
+    if (!pc) {
+	/* bytecode is starting from scratch */
+	checkInterp = 0;
+	pc = codePtr->codeStart;
+	goto cleanup0;
+    } else {
+        /* resume from invocation */
+	CACHE_STACK_INFO();
 	if (iPtr->execEnvPtr->rewind) {
 	    result = TCL_ERROR;
+	    goto abnormalReturn;
 	}
+
 	NRE_ASSERT(iPtr->cmdFramePtr == bcFramePtr);
 	if (bcFramePtr->cmdObj) {
 	    Tcl_DecrRefCount(bcFramePtr->cmdObj);
@@ -2141,68 +2241,49 @@ TEBCresume(
 	}
 	iPtr->cmdFramePtr = bcFramePtr->nextPtr;
 	if (iPtr->flags & INTERP_DEBUG_FRAME) {
-	    TclArgumentBCRelease((Tcl_Interp *) iPtr, bcFramePtr);
+	    TclArgumentBCRelease(interp, bcFramePtr);
 	}
 	if (codePtr->flags & TCL_BYTECODE_RECOMPILE) {
 	    iPtr->flags |= ERR_ALREADY_LOGGED;
 	    codePtr->flags &= ~TCL_BYTECODE_RECOMPILE;
 	}
 
-	CACHE_STACK_INFO();
-	if (result == TCL_OK) {
-	    /*
-	     * Push the call's object result and continue execution with the
-	     * next instruction.
-	     */
-
-	    TRACE_WITH_OBJ(("%u => ... after \"%.20s\": TCL_OK, result=",
-		    objc, cmdNameBuf), Tcl_GetObjResult(interp));
-
-	    /*
-	     * Reset the interp's result to avoid possible duplications of
-	     * large objects [Bug 781585]. We do not call Tcl_ResetResult to
-	     * avoid any side effects caused by the resetting of errorInfo and
-	     * errorCode [Bug 804681], which are not needed here. We chose
-	     * instead to manipulate the interp's object result directly.
-	     *
-	     * Note that the result object is now in objResultPtr, it keeps
-	     * the refCount it had in its role of iPtr->objResultPtr.
-	     */
-
-	    objResultPtr = Tcl_GetObjResult(interp);
-	    TclNewObj(objPtr);
-	    Tcl_IncrRefCount(objPtr);
-	    iPtr->objResultPtr = objPtr;
-#ifndef TCL_COMPILE_DEBUG
-	    if (*pc == INST_POP) {
-		TclDecrRefCount(objResultPtr);
-		NEXT_INST_V(1, cleanup, 0);
-	    }
-#endif
-	    NEXT_INST_V(0, cleanup, -1);
+	if (result != TCL_OK) {
+	    pc--;
+	    goto processExceptionReturn;
 	}
 
 	/*
-	 * Result not TCL_OK: fall through
+	 * Push the call's object result and continue execution with the next
+	 * instruction.
 	 */
-    }
 
-    if (iPtr->execEnvPtr->rewind) {
-	result = TCL_ERROR;
-	goto abnormalReturn;
-    }
+	TRACE_WITH_OBJ(("%u => ... after \"%.20s\": TCL_OK, result=",
+		objc, cmdNameBuf), Tcl_GetObjResult(interp));
 
-    if (result != TCL_OK) {
-	pc--;
-	goto processExceptionReturn;
-    }
-
-    /*
-     * Loop executing instructions until a "done" instruction, a TCL_RETURN,
-     * or some error.
-     */
+	/*
+	 * Reset the interp's result to avoid possible duplications of large
+	 * objects [Bug 781585]. We do not call Tcl_ResetResult to avoid any
+	 * side effects caused by the resetting of errorInfo and errorCode
+	 * [Bug 804681], which are not needed here. We chose instead to
+	 * manipulate the interp's object result directly.
+	 *
+	 * Note that the result object is now in objResultPtr, it keeps the
+	 * refCount it had in its role of iPtr->objResultPtr.
+	 */
 
-    goto cleanup0;
+	objResultPtr = Tcl_GetObjResult(interp);
+	TclNewObj(objPtr);
+	Tcl_IncrRefCount(objPtr);
+	iPtr->objResultPtr = objPtr;
+#ifndef TCL_COMPILE_DEBUG
+	if (*pc == INST_POP) {
+	    TclDecrRefCount(objResultPtr);
+	    NEXT_INST_V(1, cleanup, 0);
+	}
+#endif
+	NEXT_INST_V(0, cleanup, -1);
+    }
 
     /*
      * Targets for standard instruction endings; unrolled for speed in the
@@ -2413,25 +2494,93 @@ TEBCresume(
 	TRACE_APPEND(("\n"));
 	goto processExceptionReturn;
 
-    case INST_YIELD: {
-	CoroutineData *corPtr = iPtr->execEnvPtr->corPtr;
+    {
+	CoroutineData *corPtr;
+	int yieldParameter;
 
+    case INST_YIELD:
+	corPtr = iPtr->execEnvPtr->corPtr;
 	TRACE(("%.30s => ", O2S(OBJ_AT_TOS)));
 	if (!corPtr) {
 	    TRACE_APPEND(("ERROR: yield outside coroutine\n"));
 	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
 		    "yield can only be called in a coroutine", -1));
+	    DECACHE_STACK_INFO();
 	    Tcl_SetErrorCode(interp, "TCL", "COROUTINE", "ILLEGAL_YIELD",
 		    NULL);
+	    CACHE_STACK_INFO();
 	    goto gotError;
 	}
 
 #ifdef TCL_COMPILE_DEBUG
-	TRACE_WITH_OBJ(("yield, result="), iPtr->objResultPtr);
-	if (traceInstructions) {
-	    fprintf(stdout, "\n");
+	if (tclTraceExec >= 2) {
+	    if (traceInstructions) {
+		TRACE_APPEND(("YIELD...\n"));
+	    } else {
+		fprintf(stdout, "%d: (%u) yielding value \"%.30s\"\n",
+			iPtr->numLevels, (unsigned)(pc - codePtr->codeStart),
+			Tcl_GetString(OBJ_AT_TOS));
+	    }
+	    fflush(stdout);
 	}
 #endif
+	yieldParameter = 0;
+	Tcl_SetObjResult(interp, OBJ_AT_TOS);
+	goto doYield;
+
+    case INST_YIELD_TO_INVOKE:
+	corPtr = iPtr->execEnvPtr->corPtr;
+	valuePtr = OBJ_AT_TOS;
+	if (!corPtr) {
+	    TRACE(("[%.30s] => ERROR: yield outside coroutine\n",
+		    O2S(valuePtr)));
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "yieldto can only be called in a coroutine", -1));
+	    DECACHE_STACK_INFO();
+	    Tcl_SetErrorCode(interp, "TCL", "COROUTINE", "ILLEGAL_YIELD",
+		    NULL);
+	    CACHE_STACK_INFO();
+	    goto gotError;
+	}
+	if (((Namespace *)TclGetCurrentNamespace(interp))->flags & NS_DYING) {
+	    TRACE(("[%.30s] => ERROR: yield in deleted\n",
+		    O2S(valuePtr)));
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "yieldto called in deleted namespace", -1));
+	    DECACHE_STACK_INFO();
+	    Tcl_SetErrorCode(interp, "TCL", "COROUTINE", "YIELDTO_IN_DELETED",
+		    NULL);
+	    CACHE_STACK_INFO();
+	    goto gotError;
+	}
+
+#ifdef TCL_COMPILE_DEBUG
+	if (tclTraceExec >= 2) {
+	    if (traceInstructions) {
+		TRACE(("[%.30s] => YIELD...\n", O2S(valuePtr)));
+	    } else {
+		/* FIXME: What is the right thing to trace? */
+		fprintf(stdout, "%d: (%u) yielding to [%.30s]\n",
+			iPtr->numLevels, (unsigned)(pc - codePtr->codeStart),
+			Tcl_GetString(valuePtr));
+	    }
+	    fflush(stdout);
+	}
+#endif
+
+	/*
+	 * Install a tailcall record in the caller and continue with the
+	 * yield. The yield is switched into multi-return mode (via the
+	 * 'yieldParameter').
+	 */
+
+	Tcl_IncrRefCount(valuePtr);
+	iPtr->execEnvPtr = corPtr->callerEEPtr;
+	TclSetTailcall(interp, valuePtr);
+	iPtr->execEnvPtr = corPtr->eePtr;
+	yieldParameter = (PTR2INT(NULL)+1);	/*==CORO_ACTIVATE_YIELDM*/
+
+    doYield:
 	/* TIP #280: Record the last piece of info needed by
 	 * 'TclGetSrcInfoForPc', and push the frame.
 	 */
@@ -2440,21 +2589,14 @@ TEBCresume(
 	iPtr->cmdFramePtr = bcFramePtr;
 
 	if (iPtr->flags & INTERP_DEBUG_FRAME) {
-	    int cmd;
-	    if (GetSrcInfoForPc(pc, codePtr, NULL, NULL, &cmd)) {
-		TclArgumentBCEnter((Tcl_Interp *) iPtr, objv, objc,
-			codePtr, bcFramePtr, cmd, pc - codePtr->codeStart);
-	    }
+	    ArgumentBCEnter(interp, codePtr, TD, pc, objc, objv);
 	}
 
 	pc++;
 	cleanup = 1;
 	TEBC_YIELD();
-	
-	Tcl_SetObjResult(interp, OBJ_AT_TOS);
 	TclNRAddCallback(interp, TclNRCoroutineActivateCallback, corPtr,
-		INT2PTR(0), NULL, NULL);
-
+		INT2PTR(yieldParameter), NULL, NULL);
 	return TCL_OK;
     }
 
@@ -2467,11 +2609,14 @@ TEBCresume(
 	    TRACE(("%d => ERROR: tailcall in non-proc context\n", opnd));
 	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
 		    "tailcall can only be called from a proc or lambda", -1));
+	    DECACHE_STACK_INFO();
 	    Tcl_SetErrorCode(interp, "TCL", "TAILCALL", "ILLEGAL", NULL);
+	    CACHE_STACK_INFO();
 	    goto gotError;
 	}
 
 #ifdef TCL_COMPILE_DEBUG
+	/* FIXME: What is the right thing to trace? */
 	{
 	    register int i;
 
@@ -2545,7 +2690,7 @@ TEBCresume(
     case INST_OVER:
 	opnd = TclGetUInt4AtPtr(pc+1);
 	objResultPtr = OBJ_AT_DEPTH(opnd);
-	TRACE_WITH_OBJ(("=> "), objResultPtr);
+	TRACE_WITH_OBJ(("%u => ", opnd), objResultPtr);
 	NEXT_INST_F(5, 0, 1);
 
     case INST_REVERSE: {
@@ -2560,10 +2705,11 @@ TEBCresume(
 	    *b = tmpPtr;
 	    a++; b--;
 	}
+	TRACE(("%u => OK\n", opnd));
 	NEXT_INST_F(5, 0, 0);
     }
 
-    case INST_CONCAT1: {
+    case INST_STR_CONCAT1: {
 	int appendLen = 0;
 	char *bytes, *p;
 	Tcl_Obj **currPtr;
@@ -2712,6 +2858,17 @@ TEBCresume(
 	NEXT_INST_V(2, opnd, 1);
     }
 
+    case INST_CONCAT_STK:
+	/*
+	 * Pop the opnd (objc) top stack elements, run through Tcl_ConcatObj,
+	 * and then decrement their ref counts.
+	 */
+
+	opnd = TclGetUInt4AtPtr(pc+1);
+	objResultPtr = Tcl_ConcatObj(opnd, &OBJ_AT_DEPTH(opnd-1));
+	TRACE_WITH_OBJ(("%u => ", opnd), objResultPtr);
+	NEXT_INST_V(5, opnd, 1);
+
     case INST_EXPAND_START:
 	/*
 	 * Push an element to the auxObjList. This records the current
@@ -2730,6 +2887,7 @@ TEBCresume(
 	objPtr->internalRep.ptrAndLongRep.value = CURR_DEPTH;
 	objPtr->length = 0;
 	PUSH_TAUX_OBJ(objPtr);
+	TRACE(("=> mark depth as %d\n", (int) CURR_DEPTH));
 	NEXT_INST_F(1, 0, 0);
 
     case INST_EXPAND_DROP:
@@ -2746,6 +2904,7 @@ TEBCresume(
 	/* Ugly abuse! */
 	starting = 1;
 #endif
+	TRACE(("=> drop %d items\n", objc));
 	NEXT_INST_V(1, objc, 0);
 
     case INST_EXPAND_STKTOP: {
@@ -2759,9 +2918,9 @@ TEBCresume(
 	 */
 
 	objPtr = OBJ_AT_TOS;
+	TRACE(("\"%.30s\" => ", O2S(objPtr)));
 	if (TclListObjGetElements(interp, objPtr, &objc, &objv) != TCL_OK) {
-	    TRACE_WITH_OBJ(("%.30s => ERROR: ", O2S(objPtr)),
-		    Tcl_GetObjResult(interp));
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 	(void) POP_OBJECT();
@@ -2805,6 +2964,7 @@ TEBCresume(
 	    PUSH_OBJECT(objv[i]);
 	}
 
+	TRACE_APPEND(("OK\n"));
 	Tcl_DecrRefCount(objPtr);
 	NEXT_INST_F(5, 0, 0);
     }
@@ -2897,11 +3057,7 @@ TEBCresume(
 	iPtr->cmdFramePtr = bcFramePtr;
 
 	if (iPtr->flags & INTERP_DEBUG_FRAME) {
-	    int cmd;
-	    if (GetSrcInfoForPc(pc, codePtr, NULL, NULL, &cmd)) {
-		TclArgumentBCEnter((Tcl_Interp *) iPtr, objv, objc,
-			codePtr, bcFramePtr, cmd, pc - codePtr->codeStart);
-	    }
+	    ArgumentBCEnter(interp, codePtr, TD, pc, objc, objv);
 	}
 
 	DECACHE_STACK_INFO();
@@ -3046,11 +3202,7 @@ TEBCresume(
 	bcFramePtr->data.tebc.pc = (char *) pc;
 	iPtr->cmdFramePtr = bcFramePtr;
 	if (iPtr->flags & INTERP_DEBUG_FRAME) {
-	    int cmd;
-	    if (GetSrcInfoForPc(pc, codePtr, NULL, NULL, &cmd)) {
-		TclArgumentBCEnter((Tcl_Interp *) iPtr, objv, objc,
-			codePtr, bcFramePtr, cmd, pc - codePtr->codeStart);
-	    }
+	    ArgumentBCEnter(interp, codePtr, TD, pc, objc, objv);
 	}
 	iPtr->ensembleRewrite.sourceObjs = objv;
 	iPtr->ensembleRewrite.numRemovedObjs = opnd;
@@ -3149,7 +3301,7 @@ TEBCresume(
 	varPtr = TclLookupArrayElement(interp, part1Ptr, part2Ptr,
 		TCL_LEAVE_ERR_MSG, "read", 0, 1, arrayPtr, opnd);
 	if (varPtr == NULL) {
-	    TRACE_APPEND(("ERROR: %.30s\n", O2S(Tcl_GetObjResult(interp))));
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 	cleanup = 1;
@@ -3175,7 +3327,7 @@ TEBCresume(
 		TCL_LEAVE_ERR_MSG, "read", /*createPart1*/0, /*createPart2*/1,
 		&arrayPtr);
 	if (!varPtr) {
-	    TRACE_APPEND(("ERROR: %.30s\n", O2S(Tcl_GetObjResult(interp))));
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 
@@ -3202,7 +3354,7 @@ TEBCresume(
 		part1Ptr, part2Ptr, TCL_LEAVE_ERR_MSG, opnd);
 	CACHE_STACK_INFO();
 	if (!objResultPtr) {
-	    TRACE_APPEND(("ERROR: %.30s\n", O2S(Tcl_GetObjResult(interp))));
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 	TRACE_APPEND(("%.30s\n", O2S(objResultPtr)));
@@ -3351,7 +3503,7 @@ TEBCresume(
 	varPtr = TclObjLookupVarEx(interp, objPtr,part2Ptr, TCL_LEAVE_ERR_MSG,
 		"set", /*createPart1*/ 1, /*createPart2*/ 1, &arrayPtr);
 	if (!varPtr) {
-	    TRACE_APPEND(("ERROR: %.30s\n", O2S(Tcl_GetObjResult(interp))));
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 	cleanup = ((part2Ptr == NULL)? 2 : 3);
@@ -3401,7 +3553,7 @@ TEBCresume(
 	varPtr = TclLookupArrayElement(interp, part1Ptr, part2Ptr,
 		TCL_LEAVE_ERR_MSG, "set", 1, 1, arrayPtr, opnd);
 	if (!varPtr) {
-	    TRACE_APPEND(("ERROR: %.30s\n", O2S(Tcl_GetObjResult(interp))));
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 	goto doCallPtrSetVar;
@@ -3449,7 +3601,7 @@ TEBCresume(
 		part1Ptr, part2Ptr, valuePtr, storeFlags, opnd);
 	CACHE_STACK_INFO();
 	if (!objResultPtr) {
-	    TRACE_APPEND(("ERROR: %.30s\n", O2S(Tcl_GetObjResult(interp))));
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 #ifndef TCL_COMPILE_DEBUG
@@ -3524,9 +3676,11 @@ TEBCresume(
 	varPtr = TclObjLookupVarEx(interp, objPtr, part2Ptr,
 		TCL_LEAVE_ERR_MSG, "read", 1, 1, &arrayPtr);
 	if (!varPtr) {
+	    DECACHE_STACK_INFO();
 	    Tcl_AddErrorInfo(interp,
 		    "\n    (reading value of variable to increment)");
-	    TRACE_APPEND(("ERROR: %.30s\n", O2S(Tcl_GetObjResult(interp))));
+	    CACHE_STACK_INFO();
+	    TRACE_ERROR(interp);
 	    Tcl_DecrRefCount(incrPtr);
 	    goto gotError;
 	}
@@ -3552,7 +3706,7 @@ TEBCresume(
 	varPtr = TclLookupArrayElement(interp, part1Ptr, part2Ptr,
 		TCL_LEAVE_ERR_MSG, "read", 1, 1, arrayPtr, opnd);
 	if (!varPtr) {
-	    TRACE_APPEND(("ERROR: %.30s\n", O2S(Tcl_GetObjResult(interp))));
+	    TRACE_ERROR(interp);
 	    Tcl_DecrRefCount(incrPtr);
 	    goto gotError;
 	}
@@ -3664,8 +3818,7 @@ TEBCresume(
 	    TclNewLongObj(incrPtr, increment);
 	    if (TclIncrObj(interp, objResultPtr, incrPtr) != TCL_OK) {
 		Tcl_DecrRefCount(incrPtr);
-		TRACE_APPEND(("ERROR: %.30s\n",
-			O2S(Tcl_GetObjResult(interp))));
+		TRACE_ERROR(interp);
 		goto gotError;
 	    }
 	    Tcl_DecrRefCount(incrPtr);
@@ -3702,8 +3855,7 @@ TEBCresume(
 	    }
 	    if (TclIncrObj(interp, objResultPtr, incrPtr) != TCL_OK) {
 		Tcl_DecrRefCount(incrPtr);
-		TRACE_APPEND(("ERROR: %.30s\n",
-			O2S(Tcl_GetObjResult(interp))));
+		TRACE_ERROR(interp);
 		goto gotError;
 	    }
 	    Tcl_DecrRefCount(incrPtr);
@@ -3714,8 +3866,7 @@ TEBCresume(
 	    CACHE_STACK_INFO();
 	    Tcl_DecrRefCount(incrPtr);
 	    if (objResultPtr == NULL) {
-		TRACE_APPEND(("ERROR: %.30s\n",
-			O2S(Tcl_GetObjResult(interp))));
+		TRACE_ERROR(interp);
 		goto gotError;
 	    }
 	}
@@ -3736,6 +3887,8 @@ TEBCresume(
      */
 
     case INST_EXIST_SCALAR:
+	cleanup = 0;
+	pcAdjustment = 5;
 	opnd = TclGetUInt4AtPtr(pc+1);
 	varPtr = LOCAL(opnd);
 	while (TclIsVarLink(varPtr)) {
@@ -3752,16 +3905,11 @@ TEBCresume(
 		varPtr = NULL;
 	    }
 	}
-
-	/*
-	 * Tricky! Arrays always exist.
-	 */
-
-	objResultPtr = TCONST(!varPtr || TclIsVarUndefined(varPtr) ? 0 : 1);
-	TRACE_APPEND(("%.30s\n", O2S(objResultPtr)));
-	NEXT_INST_F(5, 0, 1);
+	goto afterExistsPeephole;
 
     case INST_EXIST_ARRAY:
+	cleanup = 1;
+	pcAdjustment = 5;
 	opnd = TclGetUInt4AtPtr(pc+1);
 	part2Ptr = OBJ_AT_TOS;
 	arrayPtr = LOCAL(opnd);
@@ -3772,7 +3920,7 @@ TEBCresume(
 	if (TclIsVarArray(arrayPtr) && !ReadTraced(arrayPtr)) {
 	    varPtr = VarHashFindVar(arrayPtr->value.tablePtr, part2Ptr);
 	    if (!varPtr || !ReadTraced(varPtr)) {
-		goto doneExistArray;
+		goto afterExistsPeephole;
 	    }
 	}
 	varPtr = TclLookupArrayElement(interp, NULL, part2Ptr, 0, "access",
@@ -3789,13 +3937,11 @@ TEBCresume(
 		varPtr = NULL;
 	    }
 	}
-    doneExistArray:
-	objResultPtr = TCONST(!varPtr || TclIsVarUndefined(varPtr) ? 0 : 1);
-	TRACE_APPEND(("%.30s\n", O2S(objResultPtr)));
-	NEXT_INST_F(5, 1, 1);
+	goto afterExistsPeephole;
 
     case INST_EXIST_ARRAY_STK:
 	cleanup = 2;
+	pcAdjustment = 1;
 	part2Ptr = OBJ_AT_TOS;		/* element name */
 	part1Ptr = OBJ_UNDER_TOS;	/* array name */
 	TRACE(("\"%.30s(%.30s)\" => ", O2S(part1Ptr), O2S(part2Ptr)));
@@ -3803,6 +3949,7 @@ TEBCresume(
 
     case INST_EXIST_STK:
 	cleanup = 1;
+	pcAdjustment = 1;
 	part2Ptr = NULL;
 	part1Ptr = OBJ_AT_TOS;		/* variable name */
 	TRACE(("\"%.30s\" => ", O2S(part1Ptr)));
@@ -3822,9 +3969,17 @@ TEBCresume(
 		varPtr = NULL;
 	    }
 	}
-	objResultPtr = TCONST(!varPtr || TclIsVarUndefined(varPtr) ? 0 : 1);
-	TRACE_APPEND(("%.30s\n", O2S(objResultPtr)));
-	NEXT_INST_V(1, cleanup, 1);
+
+	/*
+	 * Peep-hole optimisation: if you're about to jump, do jump from here.
+	 */
+
+    afterExistsPeephole: {
+	int found = (varPtr && !TclIsVarUndefined(varPtr));
+
+	TRACE_APPEND(("%d\n", found ? 1 : 0));
+	JUMP_PEEPHOLE_V(found, pcAdjustment, cleanup);
+    }
 
     /*
      *	   End of INST_EXIST instructions.
@@ -3842,7 +3997,7 @@ TEBCresume(
 	while (TclIsVarLink(varPtr)) {
 	    varPtr = varPtr->value.linkPtr;
 	}
-	TRACE(("%s %u\n", (flags?"normal":"noerr"), opnd));
+	TRACE(("%s %u => ", (flags ? "normal" : "noerr"), opnd));
 	if (TclIsVarDirectUnsettable(varPtr) && !TclIsVarInHash(varPtr)) {
 	    /*
 	     * No errors, no traces, no searches: just make the variable cease
@@ -3855,6 +4010,7 @@ TEBCresume(
 		goto slowUnsetScalar;
 	    }
 	    varPtr->value.objPtr = NULL;
+	    TRACE_APPEND(("OK\n"));
 	    NEXT_INST_F(6, 0, 0);
 	}
 
@@ -3875,7 +4031,7 @@ TEBCresume(
 	while (TclIsVarLink(arrayPtr)) {
 	    arrayPtr = arrayPtr->value.linkPtr;
 	}
-	TRACE(("%s %u \"%.30s\"\n",
+	TRACE(("%s %u \"%.30s\" => ",
 		(flags ? "normal" : "noerr"), opnd, O2S(part2Ptr)));
 	if (TclIsVarArray(arrayPtr) && !UnsetTraced(arrayPtr)) {
 	    varPtr = VarHashFindVar(arrayPtr->value.tablePtr, part2Ptr);
@@ -3891,12 +4047,14 @@ TEBCresume(
 		    goto slowUnsetArray;
 		}
 		varPtr->value.objPtr = NULL;
+		TRACE_APPEND(("OK\n"));
 		NEXT_INST_F(6, 1, 0);
 	    } else if (!varPtr && !(flags & TCL_LEAVE_ERR_MSG)) {
 		/*
 		 * Don't need to do anything here.
 		 */
 
+		TRACE_APPEND(("OK\n"));
 		NEXT_INST_F(6, 1, 0);
 	    }
 	}
@@ -3920,7 +4078,7 @@ TEBCresume(
 	cleanup = 2;
 	part2Ptr = OBJ_AT_TOS;		/* element name */
 	part1Ptr = OBJ_UNDER_TOS;	/* array name */
-	TRACE(("%s \"%.30s(%.30s)\"\n", (flags?"normal":"noerr"),
+	TRACE(("%s \"%.30s(%.30s)\" => ", (flags ? "normal" : "noerr"),
 		O2S(part1Ptr), O2S(part2Ptr)));
 	goto doUnsetStk;
 
@@ -3929,7 +4087,8 @@ TEBCresume(
 	cleanup = 1;
 	part2Ptr = NULL;
 	part1Ptr = OBJ_AT_TOS;		/* variable name */
-	TRACE(("%s \"%.30s\"\n", (flags?"normal":"noerr"), O2S(part1Ptr)));
+	TRACE(("%s \"%.30s\" => ", (flags ? "normal" : "noerr"),
+		O2S(part1Ptr)));
 
     doUnsetStk:
 	DECACHE_STACK_INFO();
@@ -3938,11 +4097,12 @@ TEBCresume(
 	    goto errorInUnset;
 	}
 	CACHE_STACK_INFO();
+	TRACE_APPEND(("OK\n"));
 	NEXT_INST_V(2, cleanup, 0);
 
     errorInUnset:
 	CACHE_STACK_INFO();
-	TRACE_APPEND(("ERROR: %.30s\n", O2S(Tcl_GetObjResult(interp))));
+	TRACE_ERROR(interp);
 	goto gotError;
 
 	/*
@@ -3951,7 +4111,7 @@ TEBCresume(
 
     case INST_DICT_DONE:
 	opnd = TclGetUInt4AtPtr(pc+1);
-	TRACE(("%u\n", opnd));
+	TRACE(("%u => OK\n", opnd));
 	varPtr = LOCAL(opnd);
 	while (TclIsVarLink(varPtr)) {
 	    varPtr = varPtr->value.linkPtr;
@@ -4004,8 +4164,7 @@ TEBCresume(
 		    TCL_GLOBAL_ONLY|TCL_TRACE_ARRAY), 1, opnd);
 	    CACHE_STACK_INFO();
 	    if (result == TCL_ERROR) {
-		TRACE_APPEND(("ERROR: %.30s\n",
-			O2S(Tcl_GetObjResult(interp))));
+		TRACE_ERROR(interp);
 		goto gotError;
 	    }
 	}
@@ -4038,7 +4197,7 @@ TEBCresume(
 	varPtr = TclObjLookupVarEx(interp, part1Ptr, NULL, TCL_LEAVE_ERR_MSG,
 		"set", /*createPart1*/1, /*createPart2*/0, &arrayPtr);
 	if (varPtr == NULL) {
-	    TRACE_APPEND(("ERROR: %.30s\n", O2S(Tcl_GetObjResult(interp))));
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
     doArrayMake:
@@ -4050,9 +4209,10 @@ TEBCresume(
 
 		TclObjVarErrMsg(interp, part1Ptr, NULL, "array set",
 			"variable isn't array", opnd);
+		DECACHE_STACK_INFO();
 		Tcl_SetErrorCode(interp, "TCL", "WRITE", "ARRAY", NULL);
-		TRACE_APPEND(("ERROR: bad array ref: %.30s\n",
-			O2S(Tcl_GetObjResult(interp))));
+		CACHE_STACK_INFO();
+		TRACE_ERROR(interp);
 		goto gotError;
 	    }
 	    TclSetVarArray(varPtr);
@@ -4080,9 +4240,11 @@ TEBCresume(
 	Namespace *savedNsPtr;
 
     case INST_UPVAR:
-	TRACE_WITH_OBJ(("upvar "), OBJ_UNDER_TOS);
+	TRACE(("%d %.30s %.30s => ", TclGetInt4AtPtr(pc+1),
+		O2S(OBJ_UNDER_TOS), O2S(OBJ_AT_TOS)));
 
 	if (TclObjGetFrame(interp, OBJ_UNDER_TOS, &framePtr) == -1) {
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 
@@ -4097,13 +4259,16 @@ TEBCresume(
 		/*createPart2*/ 1, &varPtr);
 	iPtr->varFramePtr = savedFramePtr;
 	if (!otherPtr) {
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 	goto doLinkVars;
 
     case INST_NSUPVAR:
-	TRACE_WITH_OBJ(("nsupvar "), OBJ_UNDER_TOS);
+	TRACE(("%d %.30s %.30s => ", TclGetInt4AtPtr(pc+1),
+		O2S(OBJ_UNDER_TOS), O2S(OBJ_AT_TOS)));
 	if (TclGetNamespaceFromObj(interp, OBJ_UNDER_TOS, &nsPtr) != TCL_OK) {
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 
@@ -4118,16 +4283,18 @@ TEBCresume(
 		/*createPart1*/ 1, /*createPart2*/ 1, &varPtr);
 	iPtr->varFramePtr->nsPtr = savedNsPtr;
 	if (!otherPtr) {
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 	goto doLinkVars;
 
     case INST_VARIABLE:
-	TRACE(("variable "));
+	TRACE(("%d, %.30s => ", TclGetInt4AtPtr(pc+1), O2S(OBJ_AT_TOS)));
 	otherPtr = TclObjLookupVarEx(interp, OBJ_AT_TOS, NULL,
 		(TCL_NAMESPACE_ONLY | TCL_LEAVE_ERR_MSG), "access",
 		/*createPart1*/ 1, /*createPart2*/ 1, &varPtr);
 	if (!otherPtr) {
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 
@@ -4145,7 +4312,7 @@ TEBCresume(
 	 * if there are no errors; otherwise, let it handle the case.
 	 */
 
-	opnd = TclGetInt4AtPtr(pc+1);;
+	opnd = TclGetInt4AtPtr(pc+1);
 	varPtr = LOCAL(opnd);
 	if ((varPtr != otherPtr) && !TclIsVarTraced(varPtr)
 		&& (TclIsVarUndefined(varPtr) || TclIsVarLink(varPtr))) {
@@ -4157,6 +4324,7 @@ TEBCresume(
 		Var *linkPtr = varPtr->value.linkPtr;
 
 		if (linkPtr == otherPtr) {
+		    TRACE_APPEND(("already linked\n"));
 		    NEXT_INST_F(5, 1, 0);
 		}
 		if (TclIsVarInHash(linkPtr)) {
@@ -4173,6 +4341,7 @@ TEBCresume(
 	    }
 	} else if (TclPtrObjMakeUpvar(interp, otherPtr, NULL, 0,
 		opnd) != TCL_OK) {
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 
@@ -4181,6 +4350,7 @@ TEBCresume(
 	 * variables - and [variable] did not push it at all.
 	 */
 
+	TRACE_APPEND(("link made\n"));
 	NEXT_INST_F(5, 1, 0);
     }
 
@@ -4227,31 +4397,29 @@ TEBCresume(
 
     doCondJump:
 	valuePtr = OBJ_AT_TOS;
+	TRACE(("%d => ", jmpOffset[
+		(*pc==INST_JUMP_FALSE1 || *pc==INST_JUMP_FALSE4) ? 0 : 1]));
 
 	/* TODO - check claim that taking address of b harms performance */
 	/* TODO - consider optimization search for constants */
 	if (TclGetBooleanFromObj(interp, valuePtr, &b) != TCL_OK) {
-	    TRACE_WITH_OBJ(("%d => ERROR: ", jmpOffset[
-		    ((*pc == INST_JUMP_FALSE1) || (*pc == INST_JUMP_FALSE4))
-		    ? 0 : 1]), Tcl_GetObjResult(interp));
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 
 #ifdef TCL_COMPILE_DEBUG
 	if (b) {
 	    if ((*pc == INST_JUMP_TRUE1) || (*pc == INST_JUMP_TRUE4)) {
-		TRACE(("%d => %.20s true, new pc %u\n", jmpOffset[1],
-			O2S(valuePtr),
+		TRACE_APPEND(("%.20s true, new pc %u\n", O2S(valuePtr),
 			(unsigned)(pc + jmpOffset[1] - codePtr->codeStart)));
 	    } else {
-		TRACE(("%d => %.20s true\n", jmpOffset[0], O2S(valuePtr)));
+		TRACE_APPEND(("%.20s true\n", O2S(valuePtr)));
 	    }
 	} else {
 	    if ((*pc == INST_JUMP_TRUE1) || (*pc == INST_JUMP_TRUE4)) {
-		TRACE(("%d => %.20s false\n", jmpOffset[0], O2S(valuePtr)));
+		TRACE_APPEND(("%.20s false\n", O2S(valuePtr)));
 	    } else {
-		TRACE(("%d => %.20s false, new pc %u\n", jmpOffset[0],
-			O2S(valuePtr),
+		TRACE_APPEND(("%.20s false, new pc %u\n", O2S(valuePtr),
 			(unsigned)(pc + jmpOffset[0] - codePtr->codeStart)));
 	    }
 	}
@@ -4270,7 +4438,7 @@ TEBCresume(
 
 	opnd = TclGetInt4AtPtr(pc+1);
 	jtPtr = (JumptableInfo *) codePtr->auxDataArrayPtr[opnd].clientData;
-	TRACE(("%d => %.20s ", opnd, O2S(OBJ_AT_TOS)));
+	TRACE(("%d \"%.20s\" => ", opnd, O2S(OBJ_AT_TOS)));
 	hPtr = Tcl_FindHashEntry(&jtPtr->hashTable, TclGetString(OBJ_AT_TOS));
 	if (hPtr != NULL) {
 	    int jumpOffset = PTR2INT(Tcl_GetHashValue(hPtr));
@@ -4365,13 +4533,11 @@ TEBCresume(
 	register CallFrame *framePtr = iPtr->varFramePtr;
 	register CallFrame *rootFramePtr = iPtr->rootFramePtr;
 
-	valuePtr = OBJ_AT_TOS;
-	if (TclGetIntFromObj(interp, valuePtr, &level) != TCL_OK) {
-	    TRACE_WITH_OBJ(("%.30s => ERROR: ", O2S(valuePtr)),
-		    Tcl_GetObjResult(interp));
+	TRACE(("\"%.30s\" => ", O2S(OBJ_AT_TOS)));
+	if (TclGetIntFromObj(interp, OBJ_AT_TOS, &level) != TCL_OK) {
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
-	TRACE(("%d => ", level));
 	if (level <= 0) {
 	    level += framePtr->level;
 	}
@@ -4380,38 +4546,76 @@ TEBCresume(
 	    /* Empty loop body */
 	}
 	if (framePtr == rootFramePtr) {
-	    Tcl_AppendResult(interp, "bad level \"", TclGetString(valuePtr),
-		    "\"", NULL);
-	    TRACE_APPEND(("ERROR: bad level\n"));
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "bad level \"%s\"", TclGetString(OBJ_AT_TOS)));
+	    TRACE_ERROR(interp);
+	    DECACHE_STACK_INFO();
 	    Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "STACK_LEVEL",
-		    TclGetString(valuePtr), NULL);
+		    TclGetString(OBJ_AT_TOS), NULL);
+	    CACHE_STACK_INFO();
 	    goto gotError;
 	}
 	objResultPtr = Tcl_NewListObj(framePtr->objc, framePtr->objv);
 	TRACE_APPEND(("%.30s\n", O2S(objResultPtr)));
 	NEXT_INST_F(1, 1, 1);
     }
-    case INST_RESOLVE_COMMAND: {
-	Tcl_Command cmd = Tcl_GetCommandFromObj(interp, OBJ_AT_TOS);
+    {
+	Tcl_Command cmd, origCmd;
 
+    case INST_RESOLVE_COMMAND:
+	cmd = Tcl_GetCommandFromObj(interp, OBJ_AT_TOS);
 	TclNewObj(objResultPtr);
 	if (cmd != NULL) {
 	    Tcl_GetCommandFullName(interp, cmd, objResultPtr);
 	}
 	TRACE_WITH_OBJ(("\"%.20s\" => ", O2S(OBJ_AT_TOS)), objResultPtr);
 	NEXT_INST_F(1, 1, 1);
+
+    case INST_ORIGIN_COMMAND:
+	TRACE(("\"%.30s\" => ", O2S(OBJ_AT_TOS)));
+	cmd = Tcl_GetCommandFromObj(interp, OBJ_AT_TOS);
+	if (cmd == NULL) {
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "invalid command name \"%s\"", TclGetString(OBJ_AT_TOS)));
+	    DECACHE_STACK_INFO();
+	    Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "COMMAND",
+		    TclGetString(OBJ_AT_TOS), NULL);
+	    CACHE_STACK_INFO();
+	    TRACE_APPEND(("ERROR: not command\n"));
+	    goto gotError;
+	}
+	origCmd = TclGetOriginalCommand(cmd);
+	if (origCmd == NULL) {
+	    origCmd = cmd;
+	}
+	TclNewObj(objResultPtr);
+	Tcl_GetCommandFullName(interp, origCmd, objResultPtr);
+	TRACE_APPEND(("\"%.30s\"", O2S(OBJ_AT_TOS)));
+	NEXT_INST_F(1, 1, 1);
     }
-    case INST_TCLOO_SELF: {
-	CallFrame *framePtr = iPtr->varFramePtr;
+
+    /*
+     * -----------------------------------------------------------------
+     *	   Start of TclOO support instructions.
+     */
+
+    {
+	Object *oPtr;
+	CallFrame *framePtr;
 	CallContext *contextPtr;
+	int skip, newDepth;
 
+    case INST_TCLOO_SELF:
+	framePtr = iPtr->varFramePtr;
 	if (framePtr == NULL ||
 		!(framePtr->isProcCallFrame & FRAME_IS_METHOD)) {
 	    TRACE(("=> ERROR: no TclOO call context\n"));
 	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
 		    "self may only be called from inside a method",
 		    -1));
+	    DECACHE_STACK_INFO();
 	    Tcl_SetErrorCode(interp, "TCL", "OO", "CONTEXT_REQUIRED", NULL);
+	    CACHE_STACK_INFO();
 	    goto gotError;
 	}
 	contextPtr = framePtr->clientData;
@@ -4423,9 +4627,212 @@ TEBCresume(
 	objResultPtr = TclOOObjectName(interp, contextPtr->oPtr);
 	TRACE_WITH_OBJ(("=> "), objResultPtr);
 	NEXT_INST_F(1, 0, 1);
-    }
-    {
-	Object *oPtr;
+
+    case INST_TCLOO_NEXT_CLASS:
+	opnd = TclGetUInt1AtPtr(pc+1);
+	framePtr = iPtr->varFramePtr;
+	valuePtr = OBJ_AT_DEPTH(opnd - 2);
+	objv = &OBJ_AT_DEPTH(opnd - 1);
+	skip = 2;
+	TRACE(("%d => ", opnd));
+	if (framePtr == NULL ||
+		!(framePtr->isProcCallFrame & FRAME_IS_METHOD)) {
+	    TRACE_APPEND(("ERROR: no TclOO call context\n"));
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "nextto may only be called from inside a method",
+		    -1));
+	    DECACHE_STACK_INFO();
+	    Tcl_SetErrorCode(interp, "TCL", "OO", "CONTEXT_REQUIRED", NULL);
+	    CACHE_STACK_INFO();
+	    goto gotError;
+	}
+	contextPtr = framePtr->clientData;
+
+	oPtr = (Object *) Tcl_GetObjectFromObj(interp, valuePtr);
+	if (oPtr == NULL) {
+	    TRACE_APPEND(("ERROR: \"%.30s\" not object\n", O2S(valuePtr)));
+	    goto gotError;
+	} else {
+	    Class *classPtr = oPtr->classPtr;
+	    struct MInvoke *miPtr;
+	    int i;
+	    const char *methodType;
+
+	    if (classPtr == NULL) {
+		TRACE_APPEND(("ERROR: \"%.30s\" not class\n", O2S(valuePtr)));
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"\"%s\" is not a class", TclGetString(valuePtr)));
+		DECACHE_STACK_INFO();
+		Tcl_SetErrorCode(interp, "TCL", "OO", "CLASS_REQUIRED", NULL);
+		CACHE_STACK_INFO();
+		goto gotError;
+	    }
+
+	    for (i=contextPtr->index+1 ; i<contextPtr->callPtr->numChain ; i++) {
+		miPtr = contextPtr->callPtr->chain + i;
+		if (!miPtr->isFilter &&
+			miPtr->mPtr->declaringClassPtr == classPtr) {
+		    newDepth = i;
+#ifdef TCL_COMPILE_DEBUG
+		    if (tclTraceExec >= 2) {
+			if (traceInstructions) {
+			    strncpy(cmdNameBuf, TclGetString(objv[0]), 20);
+			} else {
+			    fprintf(stdout, "%d: (%u) invoking ",
+				    iPtr->numLevels,
+				    (unsigned)(pc - codePtr->codeStart));
+			}
+			for (i = 0;  i < opnd;  i++) {
+			    TclPrintObject(stdout, objv[i], 15);
+			    fprintf(stdout, " ");
+			}
+			fprintf(stdout, "\n");
+			fflush(stdout);
+		    }
+#endif /*TCL_COMPILE_DEBUG*/
+		    goto doInvokeNext;
+		}
+	    }
+
+	    if (contextPtr->callPtr->flags & CONSTRUCTOR) {
+		methodType = "constructor";
+	    } else if (contextPtr->callPtr->flags & DESTRUCTOR) {
+		methodType = "destructor";
+	    } else {
+		methodType = "method";
+	    }
+
+	    TRACE_APPEND(("ERROR: \"%.30s\" not on reachable chain\n",
+		    O2S(valuePtr)));
+	    for (i=contextPtr->index ; i>=0 ; i--) {
+		miPtr = contextPtr->callPtr->chain + i;
+		if (miPtr->isFilter
+			|| miPtr->mPtr->declaringClassPtr != classPtr) {
+		    continue;
+		}
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"%s implementation by \"%s\" not reachable from here",
+			methodType, TclGetString(valuePtr)));
+		DECACHE_STACK_INFO();
+		Tcl_SetErrorCode(interp, "TCL", "OO", "CLASS_NOT_REACHABLE",
+			NULL);
+		CACHE_STACK_INFO();
+		goto gotError;
+	    }
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "%s has no non-filter implementation by \"%s\"",
+		    methodType, TclGetString(valuePtr)));
+	    DECACHE_STACK_INFO();
+	    Tcl_SetErrorCode(interp, "TCL", "OO", "CLASS_NOT_THERE", NULL);
+	    CACHE_STACK_INFO();
+	    goto gotError;
+	}
+
+    case INST_TCLOO_NEXT:
+	opnd = TclGetUInt1AtPtr(pc+1);
+	objv = &OBJ_AT_DEPTH(opnd - 1);
+	framePtr = iPtr->varFramePtr;
+	skip = 1;
+	TRACE(("%d => ", opnd));
+	if (framePtr == NULL ||
+		!(framePtr->isProcCallFrame & FRAME_IS_METHOD)) {
+	    TRACE_APPEND(("ERROR: no TclOO call context\n"));
+	    Tcl_SetObjResult(interp, Tcl_NewStringObj(
+		    "next may only be called from inside a method",
+		    -1));
+	    DECACHE_STACK_INFO();
+	    Tcl_SetErrorCode(interp, "TCL", "OO", "CONTEXT_REQUIRED", NULL);
+	    CACHE_STACK_INFO();
+	    goto gotError;
+	}
+	contextPtr = framePtr->clientData;
+
+	newDepth = contextPtr->index + 1;
+	if (newDepth >= contextPtr->callPtr->numChain) {
+	    /*
+	     * We're at the end of the chain; generate an error message unless
+	     * the interpreter is being torn down, in which case we might be
+	     * getting here because of methods/destructors doing a [next] (or
+	     * equivalent) unexpectedly.
+	     */
+
+	    const char *methodType;
+
+	    if (contextPtr->callPtr->flags & CONSTRUCTOR) {
+		methodType = "constructor";
+	    } else if (contextPtr->callPtr->flags & DESTRUCTOR) {
+		methodType = "destructor";
+	    } else {
+		methodType = "method";
+	    }
+
+	    TRACE_APPEND(("ERROR: no TclOO next impl\n"));
+	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		    "no next %s implementation", methodType));
+	    DECACHE_STACK_INFO();
+	    Tcl_SetErrorCode(interp, "TCL", "OO", "NOTHING_NEXT", NULL);
+	    CACHE_STACK_INFO();
+	    goto gotError;
+#ifdef TCL_COMPILE_DEBUG
+	} else if (tclTraceExec >= 2) {
+	    int i;
+
+	    if (traceInstructions) {
+		strncpy(cmdNameBuf, TclGetString(objv[0]), 20);
+	    } else {
+		fprintf(stdout, "%d: (%u) invoking ",
+			iPtr->numLevels, (unsigned)(pc - codePtr->codeStart));
+	    }
+	    for (i = 0;  i < opnd;  i++) {
+		TclPrintObject(stdout, objv[i], 15);
+		fprintf(stdout, " ");
+	    }
+	    fprintf(stdout, "\n");
+	    fflush(stdout);
+#endif /*TCL_COMPILE_DEBUG*/
+	}
+
+    doInvokeNext:
+	bcFramePtr->data.tebc.pc = (char *) pc;
+	iPtr->cmdFramePtr = bcFramePtr;
+
+	if (iPtr->flags & INTERP_DEBUG_FRAME) {
+	    ArgumentBCEnter(interp, codePtr, TD, pc, opnd, objv);
+	}
+
+	pcAdjustment = 2;
+	cleanup = opnd;
+	DECACHE_STACK_INFO();
+	iPtr->varFramePtr = framePtr->callerVarPtr;
+	pc += pcAdjustment;
+	TEBC_YIELD();
+
+	oPtr = contextPtr->oPtr;
+	if (oPtr->flags & FILTER_HANDLING) {
+	    TclNRAddCallback(interp, FinalizeOONextFilter,
+		    framePtr, contextPtr, INT2PTR(contextPtr->index),
+		    INT2PTR(contextPtr->skip));
+	} else {
+	    TclNRAddCallback(interp, FinalizeOONext,
+		    framePtr, contextPtr, INT2PTR(contextPtr->index),
+		    INT2PTR(contextPtr->skip));
+	}
+	contextPtr->skip = skip;
+	contextPtr->index = newDepth;
+	if (contextPtr->callPtr->chain[newDepth].isFilter
+		|| contextPtr->callPtr->flags & FILTER_HANDLING) {
+	    oPtr->flags |= FILTER_HANDLING;
+	} else {
+	    oPtr->flags &= ~FILTER_HANDLING;
+	}
+
+	{
+	    register Method *const mPtr =
+		    contextPtr->callPtr->chain[newDepth].mPtr;
+
+	    return mPtr->typePtr->callProc(mPtr->clientData, interp,
+		    (Tcl_ObjectContext) contextPtr, opnd, objv);
+	}
 
     case INST_TCLOO_IS_OBJECT:
 	oPtr = (Object *) Tcl_GetObjectFromObj(interp, OBJ_AT_TOS);
@@ -4459,6 +4866,7 @@ TEBCresume(
     }
 
     /*
+     *     End of TclOO support instructions.
      * -----------------------------------------------------------------
      *	   Start of INST_LIST and related instructions.
      */
@@ -4480,19 +4888,19 @@ TEBCresume(
 	NEXT_INST_V(5, opnd, 1);
 
     case INST_LIST_LENGTH:
-	valuePtr = OBJ_AT_TOS;
-	if (TclListObjLength(interp, valuePtr, &length) != TCL_OK) {
-	    TRACE_WITH_OBJ(("%.30s => ERROR: ", O2S(valuePtr)),
-		    Tcl_GetObjResult(interp));
+	TRACE(("\"%.30s\" => ", O2S(OBJ_AT_TOS)));
+	if (TclListObjLength(interp, OBJ_AT_TOS, &length) != TCL_OK) {
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 	TclNewIntObj(objResultPtr, length);
-	TRACE(("%.20s => %d\n", O2S(valuePtr), length));
+	TRACE_APPEND(("%d\n", length));
 	NEXT_INST_F(1, 1, 1);
 
     case INST_LIST_INDEX:	/* lindex with objc == 3 */
 	value2Ptr = OBJ_AT_TOS;
 	valuePtr = OBJ_UNDER_TOS;
+	TRACE(("\"%.30s\" \"%.30s\" => ", O2S(valuePtr), O2S(value2Ptr)));
 
 	/*
 	 * Extract the desired list element.
@@ -4510,8 +4918,7 @@ TEBCresume(
 
 	objResultPtr = TclLindexList(interp, valuePtr, value2Ptr);
 	if (!objResultPtr) {
-	    TRACE_WITH_OBJ(("%.30s %.30s => ERROR: ", O2S(valuePtr),
-		    O2S(value2Ptr)), Tcl_GetObjResult(interp));
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 
@@ -4519,8 +4926,7 @@ TEBCresume(
 	 * Stash the list element on the stack.
 	 */
 
-	TRACE(("%.20s %.20s => %s\n",
-		O2S(valuePtr), O2S(value2Ptr), O2S(objResultPtr)));
+	TRACE_APPEND(("\"%.30s\"\n", O2S(objResultPtr)));
 	NEXT_INST_F(1, 2, -1);	/* Already has the correct refCount */
 
     case INST_LIST_INDEX_IMM:	/* lindex with objc==3 and index in bytecode
@@ -4532,6 +4938,7 @@ TEBCresume(
 
 	valuePtr = OBJ_AT_TOS;
 	opnd = TclGetInt4AtPtr(pc+1);
+	TRACE(("\%.30s\" %d => ", O2S(valuePtr), opnd));
 
 	/*
 	 * Get the contents of the list, making sure that it really is a list
@@ -4539,8 +4946,7 @@ TEBCresume(
 	 */
 
 	if (TclListObjGetElements(interp, valuePtr, &objc, &objv) != TCL_OK) {
-	    TRACE_WITH_OBJ(("\"%.30s\" %d => ERROR: ", O2S(valuePtr), opnd),
-		    Tcl_GetObjResult(interp));
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 
@@ -4563,8 +4969,7 @@ TEBCresume(
 	    TclNewObj(objResultPtr);
 	}
 
-	TRACE_WITH_OBJ(("\"%.30s\" %d => ", O2S(valuePtr), opnd),
-		objResultPtr);
+	TRACE_APPEND(("\"%.30s\"\n", O2S(objResultPtr)));
 	NEXT_INST_F(pcAdjustment, 1, 1);
 
     case INST_LIST_INDEX_MULTI:	/* 'lindex' with multiple index args */
@@ -4579,10 +4984,11 @@ TEBCresume(
 	 * Do the 'lindex' operation.
 	 */
 
+	TRACE(("%d => ", opnd));
 	objResultPtr = TclLindexFlat(interp, OBJ_AT_DEPTH(numIndices),
 		numIndices, &OBJ_AT_DEPTH(numIndices - 1));
 	if (!objResultPtr) {
-	    TRACE_WITH_OBJ(("%d => ERROR: ", opnd), Tcl_GetObjResult(interp));
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 
@@ -4590,7 +4996,7 @@ TEBCresume(
 	 * Set result.
 	 */
 
-	TRACE(("%d => %s\n", opnd, O2S(objResultPtr)));
+	TRACE_APPEND(("\"%.30s\"\n", O2S(objResultPtr)));
 	NEXT_INST_V(5, opnd, -1);
 
     case INST_LSET_FLAT:
@@ -4600,6 +5006,7 @@ TEBCresume(
 
 	opnd = TclGetUInt4AtPtr(pc + 1);
 	numIndices = opnd - 2;
+	TRACE(("%d => ", opnd));
 
 	/*
 	 * Get the old value of variable, and remove the stack ref. This is
@@ -4618,7 +5025,7 @@ TEBCresume(
 	objResultPtr = TclLsetFlat(interp, valuePtr, numIndices,
 		&OBJ_AT_DEPTH(numIndices), OBJ_AT_TOS);
 	if (!objResultPtr) {
-	    TRACE_WITH_OBJ(("%d => ERROR: ", opnd), Tcl_GetObjResult(interp));
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 
@@ -4626,7 +5033,7 @@ TEBCresume(
 	 * Set result.
 	 */
 
-	TRACE(("%d => %s\n", opnd, O2S(objResultPtr)));
+	TRACE_APPEND(("\"%.30s\"\n", O2S(objResultPtr)));
 	NEXT_INST_V(5, numIndices+1, -1);
 
     case INST_LSET_LIST:	/* 'lset' with 4 args */
@@ -4646,6 +5053,8 @@ TEBCresume(
 
 	valuePtr = OBJ_AT_TOS;
 	value2Ptr = OBJ_UNDER_TOS;
+	TRACE(("\"%.30s\" \"%.30s\" \"%.30s\" => ",
+		O2S(value2Ptr), O2S(valuePtr), O2S(objPtr)));
 
 	/*
 	 * Compute the new variable value.
@@ -4653,8 +5062,7 @@ TEBCresume(
 
 	objResultPtr = TclLsetList(interp, objPtr, value2Ptr, valuePtr);
 	if (!objResultPtr) {
-	    TRACE_WITH_OBJ(("\"%.30s\" => ERROR: ", O2S(value2Ptr)),
-		    Tcl_GetObjResult(interp));
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 
@@ -4662,7 +5070,7 @@ TEBCresume(
 	 * Set result.
 	 */
 
-	TRACE(("=> %s\n", O2S(objResultPtr)));
+	TRACE_APPEND(("\"%.30s\"\n", O2S(objResultPtr)));
 	NEXT_INST_F(1, 2, -1);
 
     case INST_LIST_RANGE_IMM:	/* lrange with objc==4 and both indices in
@@ -4675,6 +5083,8 @@ TEBCresume(
 	valuePtr = OBJ_AT_TOS;
 	fromIdx = TclGetInt4AtPtr(pc+1);
 	toIdx = TclGetInt4AtPtr(pc+5);
+	TRACE(("\"%.30s\" %d %d => ", O2S(valuePtr), TclGetInt4AtPtr(pc+1),
+		TclGetInt4AtPtr(pc+5)));
 
 	/*
 	 * Get the contents of the list, making sure that it really is a list
@@ -4682,8 +5092,7 @@ TEBCresume(
 	 */
 
 	if (TclListObjGetElements(interp, valuePtr, &objc, &objv) != TCL_OK) {
-	    TRACE_WITH_OBJ(("\"%.30s\" %d %d => ERROR: ", O2S(valuePtr),
-		    fromIdx, toIdx), Tcl_GetObjResult(interp));
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 
@@ -4740,8 +5149,6 @@ TEBCresume(
 		List *listPtr = valuePtr->internalRep.twoPtrValue.ptr1;
 
 		if (listPtr->refCount == 1) {
-		    TRACE(("\"%.30s\" %d %d => ", O2S(valuePtr),
-			    TclGetInt4AtPtr(pc+1), TclGetInt4AtPtr(pc+5)));
 		    for (index=toIdx+1; index<objc ; index++) {
 			TclDecrRefCount(objv[index]);
 		    }
@@ -4757,8 +5164,7 @@ TEBCresume(
 	    TclNewObj(objResultPtr);
 	}
 
-	TRACE_WITH_OBJ(("\"%.30s\" %d %d => ", O2S(valuePtr),
-		TclGetInt4AtPtr(pc+1), TclGetInt4AtPtr(pc+5)), objResultPtr);
+	TRACE_APPEND(("\"%.30s\"", O2S(objResultPtr)));
 	NEXT_INST_F(9, 1, 1);
 
     case INST_LIST_IN:
@@ -4767,9 +5173,9 @@ TEBCresume(
 	valuePtr = OBJ_UNDER_TOS;
 
 	s1 = TclGetStringFromObj(valuePtr, &s1len);
+	TRACE(("\"%.30s\" \"%.30s\" => ", O2S(valuePtr), O2S(value2Ptr)));
 	if (TclListObjLength(interp, value2Ptr, &length) != TCL_OK) {
-	    TRACE_WITH_OBJ(("\"%.30s\" \"%.30s\" => ERROR: ", O2S(valuePtr),
-		    O2S(value2Ptr)), Tcl_GetObjResult(interp));
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 	match = 0;
@@ -4800,7 +5206,7 @@ TEBCresume(
 	    match = !match;
 	}
 
-	TRACE(("%.20s %.20s => %d\n", O2S(valuePtr), O2S(value2Ptr), match));
+	TRACE_APPEND(("%d\n", match));
 
 	/*
 	 * Peep-hole optimisation: if you're about to jump, do jump from here.
@@ -4808,21 +5214,7 @@ TEBCresume(
 	 * for branching.
 	 */
 
-	pc++;
-#ifndef TCL_COMPILE_DEBUG
-	switch (*pc) {
-	case INST_JUMP_FALSE1:
-	    NEXT_INST_F((match ? 2 : TclGetInt1AtPtr(pc+1)), 2, 0);
-	case INST_JUMP_TRUE1:
-	    NEXT_INST_F((match ? TclGetInt1AtPtr(pc+1) : 2), 2, 0);
-	case INST_JUMP_FALSE4:
-	    NEXT_INST_F((match ? 5 : TclGetInt4AtPtr(pc+1)), 2, 0);
-	case INST_JUMP_TRUE4:
-	    NEXT_INST_F((match ? TclGetInt4AtPtr(pc+1) : 5), 2, 0);
-	}
-#endif
-	objResultPtr = TCONST(match);
-	NEXT_INST_F(0, 2, 1);
+	JUMP_PEEPHOLE_F(match, 1, 2);
 
     case INST_LIST_CONCAT:
 	value2Ptr = OBJ_AT_TOS;
@@ -4832,7 +5224,7 @@ TEBCresume(
 	    objResultPtr = Tcl_DuplicateObj(valuePtr);
 	    if (Tcl_ListObjAppendList(interp, objResultPtr,
 		    value2Ptr) != TCL_OK) {
-		TRACE_APPEND(("ERROR: %.30s\n", O2S(Tcl_GetObjResult(interp))));
+		TRACE_ERROR(interp);
 		TclDecrRefCount(objResultPtr);
 		goto gotError;
 	    }
@@ -4840,7 +5232,7 @@ TEBCresume(
 	    NEXT_INST_F(1, 2, 1);
 	} else {
 	    if (Tcl_ListObjAppendList(interp, valuePtr, value2Ptr) != TCL_OK){
-		TRACE_APPEND(("ERROR: %.30s\n", O2S(Tcl_GetObjResult(interp))));
+		TRACE_ERROR(interp);
 		goto gotError;
 	    }
 	    TRACE_APPEND(("\"%.30s\"\n", O2S(valuePtr)));
@@ -4975,25 +5367,74 @@ TEBCresume(
 		break;
 	    }
 	}
-	if (match < 0) {
-	    TclNewIntObj(objResultPtr, -1);
-	} else {
-	    objResultPtr = TCONST(match > 0);
-	}
-	TRACE(("%.20s %.20s => %s\n", O2S(valuePtr), O2S(value2Ptr),
-		O2S(objResultPtr)));
-	NEXT_INST_F(1, 2, 1);
+
+	TRACE(("\"%.20s\" \"%.20s\" => %d\n", O2S(valuePtr), O2S(value2Ptr),
+		(match < 0 ? -1 : match > 0 ? 1 : 0)));
+	JUMP_PEEPHOLE_F(match, 1, 2);
 
     case INST_STR_LEN:
 	valuePtr = OBJ_AT_TOS;
 	length = Tcl_GetCharLength(valuePtr);
 	TclNewIntObj(objResultPtr, length);
-	TRACE(("%.20s => %d\n", O2S(valuePtr), length));
+	TRACE(("\"%.20s\" => %d\n", O2S(valuePtr), length));
 	NEXT_INST_F(1, 1, 1);
 
+    case INST_STR_UPPER:
+	valuePtr = OBJ_AT_TOS;
+	TRACE(("\"%.20s\" => ", O2S(valuePtr)));
+	if (Tcl_IsShared(valuePtr)) {
+	    s1 = TclGetStringFromObj(valuePtr, &length);
+	    TclNewStringObj(objResultPtr, s1, length);
+	    length = Tcl_UtfToUpper(TclGetString(objResultPtr));
+	    Tcl_SetObjLength(objResultPtr, length);
+	    TRACE_APPEND(("\"%.20s\"\n", O2S(objResultPtr)));
+	    NEXT_INST_F(1, 1, 1);
+	} else {
+	    length = Tcl_UtfToUpper(TclGetString(valuePtr));
+	    Tcl_SetObjLength(valuePtr, length);
+	    TclFreeIntRep(valuePtr);
+	    TRACE_APPEND(("\"%.20s\"\n", O2S(valuePtr)));
+	    NEXT_INST_F(1, 0, 0);
+	}
+    case INST_STR_LOWER:
+	valuePtr = OBJ_AT_TOS;
+	TRACE(("\"%.20s\" => ", O2S(valuePtr)));
+	if (Tcl_IsShared(valuePtr)) {
+	    s1 = TclGetStringFromObj(valuePtr, &length);
+	    TclNewStringObj(objResultPtr, s1, length);
+	    length = Tcl_UtfToLower(TclGetString(objResultPtr));
+	    Tcl_SetObjLength(objResultPtr, length);
+	    TRACE_APPEND(("\"%.20s\"\n", O2S(objResultPtr)));
+	    NEXT_INST_F(1, 1, 1);
+	} else {
+	    length = Tcl_UtfToLower(TclGetString(valuePtr));
+	    Tcl_SetObjLength(valuePtr, length);
+	    TclFreeIntRep(valuePtr);
+	    TRACE_APPEND(("\"%.20s\"\n", O2S(valuePtr)));
+	    NEXT_INST_F(1, 0, 0);
+	}
+    case INST_STR_TITLE:
+	valuePtr = OBJ_AT_TOS;
+	TRACE(("\"%.20s\" => ", O2S(valuePtr)));
+	if (Tcl_IsShared(valuePtr)) {
+	    s1 = TclGetStringFromObj(valuePtr, &length);
+	    TclNewStringObj(objResultPtr, s1, length);
+	    length = Tcl_UtfToTitle(TclGetString(objResultPtr));
+	    Tcl_SetObjLength(objResultPtr, length);
+	    TRACE_APPEND(("\"%.20s\"\n", O2S(objResultPtr)));
+	    NEXT_INST_F(1, 1, 1);
+	} else {
+	    length = Tcl_UtfToTitle(TclGetString(valuePtr));
+	    Tcl_SetObjLength(valuePtr, length);
+	    TclFreeIntRep(valuePtr);
+	    TRACE_APPEND(("\"%.20s\"\n", O2S(valuePtr)));
+	    NEXT_INST_F(1, 0, 0);
+	}
+
     case INST_STR_INDEX:
 	value2Ptr = OBJ_AT_TOS;
 	valuePtr = OBJ_UNDER_TOS;
+	TRACE(("\"%.20s\" %.20s => ", O2S(valuePtr), O2S(value2Ptr)));
 
 	/*
 	 * Get char length to calulate what 'end' means.
@@ -5001,6 +5442,7 @@ TEBCresume(
 
 	length = Tcl_GetCharLength(valuePtr);
 	if (TclGetIntForIndexM(interp, value2Ptr, length-1, &index)!=TCL_OK) {
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 
@@ -5026,18 +5468,18 @@ TEBCresume(
 	    objResultPtr = Tcl_NewStringObj(buf, length);
 	}
 
-	TRACE(("%.20s %.20s => %s\n", O2S(valuePtr), O2S(value2Ptr),
-		O2S(objResultPtr)));
+	TRACE_APPEND(("\"%s\"\n", O2S(objResultPtr)));
 	NEXT_INST_F(1, 2, 1);
 
     case INST_STR_RANGE:
-	TRACE(("\"%.20s\" %s %s =>",
+	TRACE(("\"%.20s\" %.20s %.20s =>",
 		O2S(OBJ_AT_DEPTH(2)), O2S(OBJ_UNDER_TOS), O2S(OBJ_AT_TOS)));
 	length = Tcl_GetCharLength(OBJ_AT_DEPTH(2)) - 1;
 	if (TclGetIntForIndexM(interp, OBJ_UNDER_TOS, length,
 		    &fromIdx) != TCL_OK
 	    || TclGetIntForIndexM(interp, OBJ_AT_TOS, length,
 		    &toIdx) != TCL_OK) {
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 
@@ -5097,33 +5539,206 @@ TEBCresume(
 	int length3;
 	Tcl_Obj *value3Ptr;
 
+    case INST_STR_REPLACE:
+	value3Ptr = POP_OBJECT();
+	valuePtr = OBJ_AT_DEPTH(2);
+	length = Tcl_GetCharLength(valuePtr) - 1;
+	TRACE(("\"%.20s\" %s %s \"%.20s\" => ", O2S(valuePtr),
+		O2S(OBJ_UNDER_TOS), O2S(OBJ_AT_TOS), O2S(value3Ptr)));
+	if (TclGetIntForIndexM(interp, OBJ_UNDER_TOS, length,
+		    &fromIdx) != TCL_OK
+	    || TclGetIntForIndexM(interp, OBJ_AT_TOS, length,
+		    &toIdx) != TCL_OK) {
+	    TclDecrRefCount(value3Ptr);
+	    TRACE_ERROR(interp);
+	    goto gotError;
+	}
+	TclDecrRefCount(OBJ_AT_TOS);
+	(void) POP_OBJECT();
+	TclDecrRefCount(OBJ_AT_TOS);
+	(void) POP_OBJECT();
+	if (fromIdx < 0) {
+	    fromIdx = 0;
+	}
+
+	if (fromIdx > toIdx || fromIdx > length) {
+	    TRACE_APPEND(("\"%.30s\"\n", O2S(valuePtr)));
+	    TclDecrRefCount(value3Ptr);
+	    NEXT_INST_F(1, 0, 0);
+	}
+
+	if (toIdx > length) {
+	    toIdx = length;
+	}
+
+	if (fromIdx == 0 && toIdx == length) {
+	    TclDecrRefCount(OBJ_AT_TOS);
+	    OBJ_AT_TOS = value3Ptr;
+	    TRACE_APPEND(("\"%.30s\"\n", O2S(value3Ptr)));
+	    NEXT_INST_F(1, 0, 0);
+	}
+
+	length3 = Tcl_GetCharLength(value3Ptr);
+
+	/*
+	 * Remove substring. In-place.
+	 */
+
+	if (length3 == 0 && !Tcl_IsShared(valuePtr) && toIdx == length) {
+	    TclDecrRefCount(value3Ptr);
+	    Tcl_SetObjLength(valuePtr, fromIdx);
+	    TRACE_APPEND(("\"%.30s\"\n", O2S(valuePtr)));
+	    NEXT_INST_F(1, 0, 0);
+	}
+
+	/*
+	 * See if we can splice in place. This happens when the number of
+	 * characters being replaced is the same as the number of characters
+	 * in the string to be inserted.
+	 */
+
+	if (length3 - 1 == toIdx - fromIdx) {
+	    unsigned char *bytes1, *bytes2;
+
+	    if (Tcl_IsShared(valuePtr)) {
+		objResultPtr = Tcl_DuplicateObj(valuePtr);
+		if (TclIsPureByteArray(objResultPtr)
+			&& TclIsPureByteArray(value3Ptr)) {
+		    bytes1 = Tcl_GetByteArrayFromObj(objResultPtr, NULL);
+		    bytes2 = Tcl_GetByteArrayFromObj(value3Ptr, NULL);
+		    memcpy(bytes1 + fromIdx, bytes2, length3);
+		} else {
+		    ustring1 = Tcl_GetUnicodeFromObj(objResultPtr, NULL);
+		    ustring2 = Tcl_GetUnicodeFromObj(value3Ptr, NULL);
+		    memcpy(ustring1 + fromIdx, ustring2,
+			    length3 * sizeof(Tcl_UniChar));
+
+		    /*
+		     * Magic! Flush the info in the string internal rep that
+		     * refers to the about-to-be-invalidated UTF-8 rep. This
+		     * sets the 'allocated' field of the String structure to 0
+		     * to indicate that a new buffer needs to be allocated.
+		     * This is safe; we know we've got a tclStringTypePtr set
+		     * at this point (post Tcl_GetUnicodeFromObj).
+		     */
+
+		    ((int *) objResultPtr->internalRep.otherValuePtr)[1] = 0;
+		}
+		Tcl_InvalidateStringRep(objResultPtr);
+		TRACE_APPEND(("\"%.30s\"\n", O2S(objResultPtr)));
+		NEXT_INST_F(1, 1, 1);
+	    } else {
+		if (TclIsPureByteArray(valuePtr)
+			&& TclIsPureByteArray(value3Ptr)) {
+		    bytes1 = Tcl_GetByteArrayFromObj(valuePtr, NULL);
+		    bytes2 = Tcl_GetByteArrayFromObj(value3Ptr, NULL);
+		    memcpy(bytes1 + fromIdx, bytes2, length3);
+		} else {
+		    ustring1 = Tcl_GetUnicodeFromObj(valuePtr, NULL);
+		    ustring2 = Tcl_GetUnicodeFromObj(value3Ptr, NULL);
+		    memcpy(ustring1 + fromIdx, ustring2,
+			    length3 * sizeof(Tcl_UniChar));
+
+		    /*
+		     * Magic! Flush the info in the string internal rep that
+		     * refers to the about-to-be-invalidated UTF-8 rep. This
+		     * sets the 'allocated' field of the String structure to 0
+		     * to indicate that a new buffer needs to be allocated.
+		     * This is safe; we know we've got a tclStringTypePtr set
+		     * at this point (post Tcl_GetUnicodeFromObj).
+		     */
+
+		    ((int *) objResultPtr->internalRep.otherValuePtr)[1] = 0;
+		}
+		Tcl_InvalidateStringRep(valuePtr);
+		TRACE_APPEND(("\"%.30s\"\n", O2S(valuePtr)));
+		NEXT_INST_F(1, 0, 0);
+	    }
+	}
+
+	/*
+	 * Get the unicode representation; this is where we guarantee to lose
+	 * bytearrays.
+	 */
+
+	ustring1 = Tcl_GetUnicodeFromObj(valuePtr, &length);
+	length--;
+
+	/*
+	 * Remove substring using copying.
+	 */
+
+	if (length3 == 0) {
+	    if (fromIdx > 0) {
+		objResultPtr = Tcl_NewUnicodeObj(ustring1, fromIdx);
+		if (toIdx < length) {
+		    Tcl_AppendUnicodeToObj(objResultPtr, ustring1 + toIdx + 1,
+			    length - toIdx);
+		}
+	    } else {
+		objResultPtr = Tcl_NewUnicodeObj(ustring1 + toIdx + 1,
+			length - toIdx);
+	    }
+	    TclDecrRefCount(value3Ptr);
+	    TRACE_APPEND(("\"%.30s\"\n", O2S(objResultPtr)));
+	    NEXT_INST_F(1, 1, 1);
+	}
+
+	/*
+	 * Splice string pieces by full copying.
+	 */
+
+	if (fromIdx > 0) {
+	    objResultPtr = Tcl_NewUnicodeObj(ustring1, fromIdx);
+	    Tcl_AppendObjToObj(objResultPtr, value3Ptr);
+	    if (toIdx < length) {
+		Tcl_AppendUnicodeToObj(objResultPtr, ustring1 + toIdx + 1,
+			length - toIdx);
+	    }
+	} else if (Tcl_IsShared(value3Ptr)) {
+	    objResultPtr = Tcl_DuplicateObj(value3Ptr);
+	    if (toIdx < length) {
+		Tcl_AppendUnicodeToObj(objResultPtr, ustring1 + toIdx + 1,
+			length - toIdx);
+	    }
+	} else {
+	    objResultPtr = value3Ptr;
+	    if (toIdx < length) {
+		Tcl_AppendUnicodeToObj(objResultPtr, ustring1 + toIdx + 1,
+			length - toIdx);
+	    }
+	}
+	TclDecrRefCount(value3Ptr);
+	TRACE_APPEND(("\"%.30s\"\n", O2S(objResultPtr)));
+	NEXT_INST_F(1, 1, 1);
+
     case INST_STR_MAP:
 	valuePtr = OBJ_AT_TOS;		/* "Main" string. */
 	value3Ptr = OBJ_UNDER_TOS;	/* "Target" string. */
 	value2Ptr = OBJ_AT_DEPTH(2);	/* "Source" string. */
 	if (value3Ptr == value2Ptr) {
 	    objResultPtr = valuePtr;
-	    NEXT_INST_V(1, 3, 1);
+	    goto doneStringMap;
 	} else if (valuePtr == value2Ptr) {
 	    objResultPtr = value3Ptr;
-	    NEXT_INST_V(1, 3, 1);
+	    goto doneStringMap;
 	}
 	ustring1 = Tcl_GetUnicodeFromObj(valuePtr, &length);
 	if (length == 0) {
 	    objResultPtr = valuePtr;
-	    NEXT_INST_V(1, 3, 1);
+	    goto doneStringMap;
 	}
 	ustring2 = Tcl_GetUnicodeFromObj(value2Ptr, &length2);
 	if (length2 > length || length2 == 0) {
 	    objResultPtr = valuePtr;
-	    NEXT_INST_V(1, 3, 1);
+	    goto doneStringMap;
 	} else if (length2 == length) {
 	    if (memcmp(ustring1, ustring2, sizeof(Tcl_UniChar) * length)) {
 		objResultPtr = valuePtr;
 	    } else {
 		objResultPtr = value3Ptr;
 	    }
-	    NEXT_INST_V(1, 3, 1);
+	    goto doneStringMap;
 	}
 	ustring3 = Tcl_GetUnicodeFromObj(value3Ptr, &length3);
 
@@ -5152,6 +5767,7 @@ TEBCresume(
 
 	    Tcl_AppendUnicodeToObj(objResultPtr, p, ustring1 - p);
 	}
+    doneStringMap:
 	TRACE_WITH_OBJ(("%.20s %.20s %.20s => ",
 		O2S(value2Ptr), O2S(value3Ptr), O2S(valuePtr)), objResultPtr);
 	NEXT_INST_V(1, 3, 1);
@@ -5174,7 +5790,6 @@ TEBCresume(
 
 	TRACE(("%.20s %.20s => %d\n",
 		O2S(OBJ_UNDER_TOS), O2S(OBJ_AT_TOS), match));
-
 	TclNewIntObj(objResultPtr, match);
 	NEXT_INST_F(1, 2, 1);
 
@@ -5198,6 +5813,25 @@ TEBCresume(
 
 	TclNewIntObj(objResultPtr, match);
 	NEXT_INST_F(1, 2, 1);
+
+    case INST_STR_CLASS:
+	opnd = TclGetInt1AtPtr(pc+1);
+	valuePtr = OBJ_AT_TOS;
+	TRACE(("%s \"%.30s\" => ", tclStringClassTable[opnd].name,
+		O2S(valuePtr)));
+	ustring1 = Tcl_GetUnicodeFromObj(valuePtr, &length);
+	match = 1;
+	if (length > 0) {
+	    end = ustring1 + length;
+	    for (p=ustring1 ; p<end ; p++) {
+		if (!tclStringClassTable[opnd].comparator(*p)) {
+		    match = 0;
+		    break;
+		}
+	    }
+	}
+	TRACE_APPEND(("%d\n", match));
+	JUMP_PEEPHOLE_F(match, 2, 1);
     }
 
     case INST_STR_MATCH:
@@ -5240,26 +5874,77 @@ TEBCresume(
 	 * Peep-hole optimisation: if you're about to jump, do jump from here.
 	 */
 
-	pc += 2;
-#ifndef TCL_COMPILE_DEBUG
-	switch (*pc) {
-	case INST_JUMP_FALSE1:
-	    NEXT_INST_F((match? 2 : TclGetInt1AtPtr(pc+1)), 2, 0);
-	case INST_JUMP_TRUE1:
-	    NEXT_INST_F((match? TclGetInt1AtPtr(pc+1) : 2), 2, 0);
-	case INST_JUMP_FALSE4:
-	    NEXT_INST_F((match? 5 : TclGetInt4AtPtr(pc+1)), 2, 0);
-	case INST_JUMP_TRUE4:
-	    NEXT_INST_F((match? TclGetInt4AtPtr(pc+1) : 5), 2, 0);
+	JUMP_PEEPHOLE_F(match, 2, 2);
+
+    {
+	const char *string1, *string2;
+	int trim1, trim2;
+
+    case INST_STR_TRIM_LEFT:
+	valuePtr = OBJ_UNDER_TOS;	/* String */
+	value2Ptr = OBJ_AT_TOS;		/* TrimSet */
+	string2 = TclGetStringFromObj(value2Ptr, &length2);
+	string1 = TclGetStringFromObj(valuePtr, &length);
+	trim1 = TclTrimLeft(string1, length, string2, length2);
+	trim2 = 0;
+	goto createTrimmedString;
+    case INST_STR_TRIM_RIGHT:
+	valuePtr = OBJ_UNDER_TOS;	/* String */
+	value2Ptr = OBJ_AT_TOS;		/* TrimSet */
+	string2 = TclGetStringFromObj(value2Ptr, &length2);
+	string1 = TclGetStringFromObj(valuePtr, &length);
+	trim2 = TclTrimRight(string1, length, string2, length2);
+	trim1 = 0;
+	goto createTrimmedString;
+    case INST_STR_TRIM:
+	valuePtr = OBJ_UNDER_TOS;	/* String */
+	value2Ptr = OBJ_AT_TOS;		/* TrimSet */
+	string2 = TclGetStringFromObj(value2Ptr, &length2);
+	string1 = TclGetStringFromObj(valuePtr, &length);
+	trim1 = TclTrimLeft(string1, length, string2, length2);
+	if (trim1 < length) {
+	    trim2 = TclTrimRight(string1, length, string2, length2);
+	} else {
+	    trim2 = 0;
+	}
+    createTrimmedString:
+	/*
+	 * Careful here; trim set often contains non-ASCII characters so we
+	 * take care when printing. [Bug 971cb4f1db]
+	 */
+
+#ifdef TCL_COMPILE_DEBUG
+	if (traceInstructions) {
+	    TRACE(("\"%.30s\" ", O2S(valuePtr)));
+	    TclPrintObject(stdout, value2Ptr, 30);
+	    printf(" => ");
 	}
 #endif
-	objResultPtr = TCONST(match);
-	NEXT_INST_F(0, 2, 1);
+	if (trim1 == 0 && trim2 == 0) {
+#ifdef TCL_COMPILE_DEBUG
+	    if (traceInstructions) {
+		TclPrintObject(stdout, valuePtr, 30);
+		printf("\n");
+	    }
+#endif
+	    NEXT_INST_F(1, 1, 0);
+	} else {
+	    objResultPtr = Tcl_NewStringObj(string1+trim1, length-trim1-trim2);
+#ifdef TCL_COMPILE_DEBUG
+	    if (traceInstructions) {
+		TclPrintObject(stdout, objResultPtr, 30);
+		printf("\n");
+	    }
+#endif
+	    NEXT_INST_F(1, 2, 1);
+	}
+    }
 
     case INST_REGEXP:
 	cflags = TclGetInt1AtPtr(pc+1); /* RE compile flages like NOCASE */
 	valuePtr = OBJ_AT_TOS;		/* String */
 	value2Ptr = OBJ_UNDER_TOS;	/* Pattern */
+	TRACE(("\"%.30s\" \"%.30s\" => ", O2S(valuePtr), O2S(value2Ptr)));
 
 	/*
 	 * Compile and match the regular expression.
@@ -5270,44 +5955,24 @@ TEBCresume(
 		    Tcl_GetRegExpFromObj(interp, value2Ptr, cflags);
 
 	    if (regExpr == NULL) {
-		goto regexpFailure;
+		TRACE_ERROR(interp);
+		goto gotError;
 	    }
-
 	    match = Tcl_RegExpExecObj(interp, regExpr, valuePtr, 0, 0, 0);
-
 	    if (match < 0) {
-	    regexpFailure:
-#ifdef TCL_COMPILE_DEBUG
-		objResultPtr = Tcl_GetObjResult(interp);
-		TRACE_WITH_OBJ(("%.20s %.20s => ERROR: ",
-			O2S(valuePtr), O2S(value2Ptr)), objResultPtr);
-#endif
+		TRACE_ERROR(interp);
 		goto gotError;
 	    }
 	}
 
-	TRACE(("%.20s %.20s => %d\n", O2S(valuePtr), O2S(value2Ptr), match));
+	TRACE_APPEND(("%d\n", match));
 
 	/*
 	 * Peep-hole optimisation: if you're about to jump, do jump from here.
 	 * Adjustment is 2 due to the nocase byte.
 	 */
 
-	pc += 2;
-#ifndef TCL_COMPILE_DEBUG
-	switch (*pc) {
-	case INST_JUMP_FALSE1:
-	    NEXT_INST_F((match? 2 : TclGetInt1AtPtr(pc+1)), 2, 0);
-	case INST_JUMP_TRUE1:
-	    NEXT_INST_F((match? TclGetInt1AtPtr(pc+1) : 2), 2, 0);
-	case INST_JUMP_FALSE4:
-	    NEXT_INST_F((match? 5 : TclGetInt4AtPtr(pc+1)), 2, 0);
-	case INST_JUMP_TRUE4:
-	    NEXT_INST_F((match? TclGetInt4AtPtr(pc+1) : 5), 2, 0);
-	}
-#endif
-	objResultPtr = TCONST(match);
-	NEXT_INST_F(0, 2, 1);
+	JUMP_PEEPHOLE_F(match, 2, 2);
     }
 
     /*
@@ -5321,6 +5986,14 @@ TEBCresume(
 	int type1, type2;
 	long l1, l2, lResult;
 
+    case INST_NUM_TYPE:
+	if (GetNumberFromObj(NULL, OBJ_AT_TOS, &ptr1, &type1) != TCL_OK) {
+	    type1 = 0;
+	}
+	TclNewIntObj(objResultPtr, type1);
+	TRACE(("\"%.20s\" => %d\n", O2S(OBJ_AT_TOS), type1));
+	NEXT_INST_F(1, 1, 1);
+
     case INST_EQ:
     case INST_NEQ:
     case INST_LT:
@@ -5405,21 +6078,9 @@ TEBCresume(
 	 */
 
     foundResult:
-	pc++;
-#ifndef TCL_COMPILE_DEBUG
-	switch (*pc) {
-	case INST_JUMP_FALSE1:
-	    NEXT_INST_F((iResult? 2 : TclGetInt1AtPtr(pc+1)), 2, 0);
-	case INST_JUMP_TRUE1:
-	    NEXT_INST_F((iResult? TclGetInt1AtPtr(pc+1) : 2), 2, 0);
-	case INST_JUMP_FALSE4:
-	    NEXT_INST_F((iResult? 5 : TclGetInt4AtPtr(pc+1)), 2, 0);
-	case INST_JUMP_TRUE4:
-	    NEXT_INST_F((iResult? TclGetInt4AtPtr(pc+1) : 5), 2, 0);
-	}
-#endif
-	objResultPtr = TCONST(iResult);
-	NEXT_INST_F(0, 2, 1);
+	TRACE(("\"%.20s\" \"%.20s\" => %d\n", O2S(valuePtr), O2S(value2Ptr),
+		iResult));
+	JUMP_PEEPHOLE_F(iResult, 1, 2);
     }
 
     case INST_MOD:
@@ -5506,13 +6167,13 @@ TEBCresume(
 		if (l2 < 0) {
 		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
 			    "negative shift argument", -1));
-#if 0
+#ifdef ERROR_CODE_FOR_EARLY_DETECTED_ARITH_ERROR
 		    DECACHE_STACK_INFO();
 		    Tcl_SetErrorCode(interp, "ARITH", "DOMAIN",
 			    "domain error: argument not in valid range",
 			    NULL);
 		    CACHE_STACK_INFO();
-#endif
+#endif /* ERROR_CODE_FOR_EARLY_DETECTED_ARITH_ERROR */
 		    goto gotError;
 		} else if (l1 == 0) {
 		    TRACE(("%s %s => ", O2S(valuePtr), O2S(value2Ptr)));
@@ -5554,13 +6215,13 @@ TEBCresume(
 		if (l2 < 0) {
 		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
 			    "negative shift argument", -1));
-#if 0
+#ifdef ERROR_CODE_FOR_EARLY_DETECTED_ARITH_ERROR
 		    DECACHE_STACK_INFO();
 		    Tcl_SetErrorCode(interp, "ARITH", "DOMAIN",
 			    "domain error: argument not in valid range",
 			    NULL);
 		    CACHE_STACK_INFO();
-#endif
+#endif /* ERROR_CODE_FOR_EARLY_DETECTED_ARITH_ERROR */
 		    goto gotError;
 		} else if (l1 == 0) {
 		    TRACE(("%s %s => ", O2S(valuePtr), O2S(value2Ptr)));
@@ -5577,12 +6238,12 @@ TEBCresume(
 
 		    Tcl_SetObjResult(interp, Tcl_NewStringObj(
 			    "integer value too large to represent", -1));
-#if 0
+#ifdef ERROR_CODE_FOR_EARLY_DETECTED_ARITH_ERROR
 		    DECACHE_STACK_INFO();
 		    Tcl_SetErrorCode(interp, "ARITH", "IOVERFLOW",
 			    "integer value too large to represent", NULL);
 		    CACHE_STACK_INFO();
-#endif
+#endif /* ERROR_CODE_FOR_EARLY_DETECTED_ARITH_ERROR */
 		    goto gotError;
 		} else {
 		    int shift = (int) l2;
@@ -5640,8 +6301,7 @@ TEBCresume(
 	    TRACE_APPEND(("DIVIDE BY ZERO\n"));
 	    goto divideByZero;
 	} else if (objResultPtr == GENERAL_ARITHMETIC_ERROR) {
-	    TRACE_APPEND(("ERROR: %s\n",
-		    TclGetString(Tcl_GetObjResult(interp))));
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	} else if (objResultPtr == NULL) {
 	    TRACE_APPEND(("%s\n", O2S(valuePtr)));
@@ -5813,8 +6473,7 @@ TEBCresume(
 	    TRACE_APPEND(("EXPONENT OF ZERO\n"));
 	    goto exponOfZero;
 	} else if (objResultPtr == GENERAL_ARITHMETIC_ERROR) {
-	    TRACE_APPEND(("ERROR: %s\n",
-		    TclGetString(Tcl_GetObjResult(interp))));
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	} else if (objResultPtr == NULL) {
 	    TRACE_APPEND(("%s\n", O2S(valuePtr)));
@@ -5832,7 +6491,7 @@ TEBCresume(
 	/* TODO - check claim that taking address of b harms performance */
 	/* TODO - consider optimization search for constants */
 	if (TclGetBooleanFromObj(NULL, valuePtr, &b) != TCL_OK) {
-	    TRACE(("\"%.20s\" => ILLEGAL TYPE %s\n", O2S(valuePtr),
+	    TRACE(("\"%.20s\" => ERROR: illegal type %s\n", O2S(valuePtr),
 		    (valuePtr->typePtr? valuePtr->typePtr->name : "null")));
 	    DECACHE_STACK_INFO();
 	    IllegalExprOperandType(interp, pc, valuePtr);
@@ -5841,18 +6500,20 @@ TEBCresume(
 	}
 	/* TODO: Consider peephole opt. */
 	objResultPtr = TCONST(!b);
+	TRACE_WITH_OBJ(("%s => ", O2S(valuePtr)), objResultPtr);
 	NEXT_INST_F(1, 1, 1);
     }
 
     case INST_BITNOT:
 	valuePtr = OBJ_AT_TOS;
+	TRACE(("\"%.20s\" => ", O2S(valuePtr)));
 	if ((GetNumberFromObj(NULL, valuePtr, &ptr1, &type1) != TCL_OK)
 		|| (type1==TCL_NUMBER_NAN) || (type1==TCL_NUMBER_DOUBLE)) {
 	    /*
 	     * ... ~$NonInteger => raise an error.
 	     */
 
-	    TRACE(("\"%.20s\" => ILLEGAL TYPE %s \n", O2S(valuePtr),
+	    TRACE_APPEND(("ERROR: illegal type %s\n",
 		    (valuePtr->typePtr? valuePtr->typePtr->name : "null")));
 	    DECACHE_STACK_INFO();
 	    IllegalExprOperandType(interp, pc, valuePtr);
@@ -5863,23 +6524,28 @@ TEBCresume(
 	    l1 = *((const long *) ptr1);
 	    if (Tcl_IsShared(valuePtr)) {
 		TclNewLongObj(objResultPtr, ~l1);
+		TRACE_APPEND(("%s\n", O2S(objResultPtr)));
 		NEXT_INST_F(1, 1, 1);
 	    }
 	    TclSetLongObj(valuePtr, ~l1);
+	    TRACE_APPEND(("%s\n", O2S(valuePtr)));
 	    NEXT_INST_F(1, 0, 0);
 	}
 	objResultPtr = ExecuteExtendedUnaryMathOp(*pc, valuePtr);
 	if (objResultPtr != NULL) {
+	    TRACE_APPEND(("%s\n", O2S(objResultPtr)));
 	    NEXT_INST_F(1, 1, 1);
 	} else {
+	    TRACE_APPEND(("%s\n", O2S(valuePtr)));
 	    NEXT_INST_F(1, 0, 0);
 	}
 
     case INST_UMINUS:
 	valuePtr = OBJ_AT_TOS;
+	TRACE(("\"%.20s\" => ", O2S(valuePtr)));
 	if ((GetNumberFromObj(NULL, valuePtr, &ptr1, &type1) != TCL_OK)
 		|| IsErroringNaNType(type1)) {
-	    TRACE(("\"%.20s\" => ILLEGAL TYPE %s \n", O2S(valuePtr),
+	    TRACE_APPEND(("ERROR: illegal type %s \n",
 		    (valuePtr->typePtr? valuePtr->typePtr->name : "null")));
 	    DECACHE_STACK_INFO();
 	    IllegalExprOperandType(interp, pc, valuePtr);
@@ -5889,23 +6555,28 @@ TEBCresume(
 	switch (type1) {
 	case TCL_NUMBER_NAN:
 	    /* -NaN => NaN */
+	    TRACE_APPEND(("%s\n", O2S(valuePtr)));
 	    NEXT_INST_F(1, 0, 0);
 	case TCL_NUMBER_LONG:
 	    l1 = *((const long *) ptr1);
 	    if (l1 != LONG_MIN) {
 		if (Tcl_IsShared(valuePtr)) {
 		    TclNewLongObj(objResultPtr, -l1);
+		    TRACE_APPEND(("%s\n", O2S(objResultPtr)));
 		    NEXT_INST_F(1, 1, 1);
 		}
 		TclSetLongObj(valuePtr, -l1);
+		TRACE_APPEND(("%s\n", O2S(valuePtr)));
 		NEXT_INST_F(1, 0, 0);
 	    }
 	    /* FALLTHROUGH */
 	}
 	objResultPtr = ExecuteExtendedUnaryMathOp(*pc, valuePtr);
 	if (objResultPtr != NULL) {
+	    TRACE_APPEND(("%s\n", O2S(objResultPtr)));
 	    NEXT_INST_F(1, 1, 1);
 	} else {
+	    TRACE_APPEND(("%s\n", O2S(valuePtr)));
 	    NEXT_INST_F(1, 0, 0);
 	}
 
@@ -5918,6 +6589,7 @@ TEBCresume(
 	 */
 
 	valuePtr = OBJ_AT_TOS;
+	TRACE(("\"%.20s\" => ", O2S(valuePtr)));
 
 	if (GetNumberFromObj(NULL, valuePtr, &ptr1, &type1) != TCL_OK) {
 	    if (*pc == INST_UPLUS) {
@@ -5925,7 +6597,7 @@ TEBCresume(
 		 * ... +$NonNumeric => raise an error.
 		 */
 
-		TRACE(("\"%.20s\" => ILLEGAL TYPE %s \n", O2S(valuePtr),
+		TRACE_APPEND(("ERROR: illegal type %s\n",
 			(valuePtr->typePtr? valuePtr->typePtr->name:"null")));
 		DECACHE_STACK_INFO();
 		IllegalExprOperandType(interp, pc, valuePtr);
@@ -5934,7 +6606,7 @@ TEBCresume(
 	    }
 
 	    /* ... TryConvertToNumeric($NonNumeric) is acceptable */
-	    TRACE(("\"%.20s\" => not numeric\n", O2S(valuePtr)));
+	    TRACE_APPEND(("not numeric\n"));
 	    NEXT_INST_F(1, 0, 0);
 	}
 	if (IsErroringNaNType(type1)) {
@@ -5943,7 +6615,7 @@ TEBCresume(
 		 * ... +$NonNumeric => raise an error.
 		 */
 
-		TRACE(("\"%.20s\" => ILLEGAL TYPE %s \n", O2S(valuePtr),
+		TRACE_APPEND(("ERROR: illegal type %s\n",
 			(valuePtr->typePtr? valuePtr->typePtr->name:"null")));
 		DECACHE_STACK_INFO();
 		IllegalExprOperandType(interp, pc, valuePtr);
@@ -5953,8 +6625,7 @@ TEBCresume(
 		 * Numeric conversion of NaN -> error.
 		 */
 
-		TRACE(("\"%.20s\" => IEEE FLOATING PT ERROR\n",
-			O2S(objResultPtr)));
+		TRACE_APPEND(("ERROR: IEEE floating pt error\n"));
 		DECACHE_STACK_INFO();
 		TclExprFloatError(interp, *((const double *) ptr1));
 		CACHE_STACK_INFO();
@@ -5972,7 +6643,7 @@ TEBCresume(
 	 */
 
 	if (valuePtr->bytes == NULL) {
-	    TRACE(("\"%.20s\" => numeric, same Tcl_Obj\n", O2S(valuePtr)));
+	    TRACE_APPEND(("numeric, same Tcl_Obj\n"));
 	    NEXT_INST_F(1, 0, 0);
 	}
 	if (Tcl_IsShared(valuePtr)) {
@@ -5987,11 +6658,11 @@ TEBCresume(
 	    valuePtr->bytes = NULL;
 	    objResultPtr = Tcl_DuplicateObj(valuePtr);
 	    valuePtr->bytes = savedString;
-	    TRACE(("\"%.20s\" => numeric, new Tcl_Obj\n", O2S(valuePtr)));
+	    TRACE_APPEND(("numeric, new Tcl_Obj\n"));
 	    NEXT_INST_F(1, 1, 1);
 	}
 	TclInvalidateStringRep(valuePtr);
-	TRACE(("\"%.20s\" => numeric, same Tcl_Obj\n", O2S(valuePtr)));
+	TRACE_APPEND(("numeric, same Tcl_Obj\n"));
 	NEXT_INST_F(1, 0, 0);
     }
 
@@ -6000,6 +6671,17 @@ TEBCresume(
      * -----------------------------------------------------------------
      */
 
+    case INST_TRY_CVT_TO_BOOLEAN:
+	valuePtr = OBJ_AT_TOS;
+	if (valuePtr->typePtr == &tclBooleanType) {
+	    objResultPtr = TCONST(1);
+	} else {
+	    int result = (TclSetBooleanFromAny(NULL, valuePtr) == TCL_OK);
+	    objResultPtr = TCONST(result);
+	}
+	TRACE_WITH_OBJ(("\"%.30s\" => ", O2S(valuePtr)), objResultPtr);
+	NEXT_INST_F(1, 0, 1);
+
     case INST_BREAK:
 	/*
 	DECACHE_STACK_INFO();
@@ -6008,6 +6690,7 @@ TEBCresume(
 	*/
 	result = TCL_BREAK;
 	cleanup = 0;
+	TRACE(("=> BREAK!\n"));
 	goto processExceptionReturn;
 
     case INST_CONTINUE:
@@ -6018,6 +6701,7 @@ TEBCresume(
 	*/
 	result = TCL_CONTINUE;
 	cleanup = 0;
+	TRACE(("=> CONTINUE!\n"));
 	goto processExceptionReturn;
 
     {
@@ -6029,7 +6713,7 @@ TEBCresume(
 	int varIndex, valIndex, continueLoop, j, iterTmpIndex;
 	long i;
 
-    case INST_FOREACH_START4:
+    case INST_FOREACH_START4: /* DEPRECATED */
 	/*
 	 * Initialize the temporary local var that holds the count of the
 	 * number of iterations of the loop body to -1.
@@ -6062,13 +6746,14 @@ TEBCresume(
 	NEXT_INST_F(5, 0, 0);
 #endif
 
-    case INST_FOREACH_STEP4:
+    case INST_FOREACH_STEP4: /* DEPRECATED */
 	/*
 	 * "Step" a foreach loop (i.e., begin its next iteration) by assigning
 	 * the next value list element to each loop var.
 	 */
 
 	opnd = TclGetUInt4AtPtr(pc+1);
+	TRACE(("%u => ", opnd));
 	infoPtr = codePtr->auxDataArrayPtr[opnd].clientData;
 	numLists = infoPtr->numLists;
 
@@ -6095,8 +6780,8 @@ TEBCresume(
 	    listVarPtr = LOCAL(listTmpIndex);
 	    listPtr = listVarPtr->value.objPtr;
 	    if (TclListObjLength(interp, listPtr, &listLen) != TCL_OK) {
-		TRACE_WITH_OBJ(("%u => ERROR converting list %ld, \"%s\": ",
-			opnd, i, O2S(listPtr)), Tcl_GetObjResult(interp));
+		TRACE_APPEND(("ERROR converting list %ld, \"%.30s\": %s\n",
+			i, O2S(listPtr), O2S(Tcl_GetObjResult(interp))));
 		goto gotError;
 	    }
 	    if (listLen > iterNum * numVars) {
@@ -6151,9 +6836,9 @@ TEBCresume(
 			if (TclPtrSetVar(interp, varPtr, NULL, NULL, NULL,
 				valuePtr, TCL_LEAVE_ERR_MSG, varIndex)==NULL){
 			    CACHE_STACK_INFO();
-			    TRACE_WITH_OBJ((
-				    "%u => ERROR init. index temp %d: ",
-				    opnd,varIndex), Tcl_GetObjResult(interp));
+			    TRACE_APPEND((
+				    "ERROR init. index temp %d: %s\n",
+				    varIndex, O2S(Tcl_GetObjResult(interp))));
 			    TclDecrRefCount(listPtr);
 			    goto gotError;
 			}
@@ -6165,8 +6850,8 @@ TEBCresume(
 		listTmpIndex++;
 	    }
 	}
-	TRACE(("%u => %d lists, iter %d, %s loop\n", opnd, numLists,
-		iterNum, (continueLoop? "continue" : "exit")));
+	TRACE_APPEND(("%d lists, iter %d, %s loop\n",
+		numLists, iterNum, (continueLoop? "continue" : "exit")));
 
 	/*
 	 * Run-time peep-hole optimisation: the compiler ALWAYS follows
@@ -6180,6 +6865,200 @@ TEBCresume(
 	} else {
 	    NEXT_INST_F((continueLoop? 5 : TclGetInt4AtPtr(pc+1)), 0, 0);
 	}
+
+    }
+    {
+	ForeachInfo *infoPtr;
+	Tcl_Obj *listPtr, **elements, *tmpPtr;
+	ForeachVarList *varListPtr;
+	int numLists, iterMax, listLen, numVars;
+	int iterTmp, iterNum, listTmpDepth;
+	int varIndex, valIndex, j;
+	long i;
+
+    case INST_FOREACH_START:
+	/*
+	 * Initialize the data for the looping construct, pushing the
+	 * corresponding Tcl_Objs to the stack.
+	 */
+
+	opnd = TclGetUInt4AtPtr(pc+1);
+	infoPtr = codePtr->auxDataArrayPtr[opnd].clientData;
+	numLists = infoPtr->numLists;
+	TRACE(("%u => ", opnd));
+
+	/*
+	 * Compute the number of iterations that will be run: iterMax
+	 */
+
+	iterMax = 0;
+	listTmpDepth = numLists-1;
+	for (i = 0;  i < numLists;  i++) {
+	    varListPtr = infoPtr->varLists[i];
+	    numVars = varListPtr->numVars;
+	    listPtr = OBJ_AT_DEPTH(listTmpDepth);
+	    if (TclListObjLength(interp, listPtr, &listLen) != TCL_OK) {
+		TRACE_APPEND(("ERROR converting list %ld, \"%s\": %s",
+			i, O2S(listPtr), O2S(Tcl_GetObjResult(interp))));
+		goto gotError;
+	    }
+	    if (Tcl_IsShared(listPtr)) {
+		objPtr = TclListObjCopy(NULL, listPtr);
+		Tcl_IncrRefCount(objPtr);
+		Tcl_DecrRefCount(listPtr);
+		OBJ_AT_DEPTH(listTmpDepth) = objPtr;
+	    }
+	    iterTmp = (listLen + (numVars - 1))/numVars;
+	    if (iterTmp > iterMax) {
+		iterMax = iterTmp;
+	    }
+	    listTmpDepth--;
+	}
+
+	/*
+	 * Store the iterNum and iterMax in a single Tcl_Obj; we keep a
+	 * nul-string obj with the pointer stored in the ptrValue so that the
+	 * thing is properly garbage collected. THIS OBJ MAKES NO SENSE, but
+	 * it will never leave this scope and is read-only.
+	 */
+
+	TclNewObj(tmpPtr);
+	tmpPtr->internalRep.twoPtrValue.ptr1 = INT2PTR(0);
+	tmpPtr->internalRep.twoPtrValue.ptr2 = INT2PTR(iterMax);
+	PUSH_OBJECT(tmpPtr); /* iterCounts object */
+
+	/*
+	 * Store a pointer to the ForeachInfo struct; same dirty trick
+	 * as above
+	 */
+
+	TclNewObj(tmpPtr);
+	tmpPtr->internalRep.otherValuePtr = infoPtr;
+	PUSH_OBJECT(tmpPtr); /* infoPtr object */
+	TRACE_APPEND(("jump to loop step\n"));
+
+	/*
+	 * Jump directly to the INST_FOREACH_STEP instruction; the C code just
+	 * falls through.
+	 */
+
+	pc += 5 - infoPtr->loopCtTemp;
+
+    case INST_FOREACH_STEP:
+	/*
+	 * "Step" a foreach loop (i.e., begin its next iteration) by assigning
+	 * the next value list element to each loop var.
+	 */
+
+	tmpPtr = OBJ_AT_TOS;
+	infoPtr = tmpPtr->internalRep.otherValuePtr;
+	numLists = infoPtr->numLists;
+	TRACE(("=> "));
+
+	tmpPtr = OBJ_AT_DEPTH(1);
+	iterNum = PTR2INT(tmpPtr->internalRep.twoPtrValue.ptr1);
+	iterMax = PTR2INT(tmpPtr->internalRep.twoPtrValue.ptr2);
+
+	/*
+	 * If some list still has a remaining list element iterate one more
+	 * time. Assign to var the next element from its value list.
+	 */
+
+	if (iterNum < iterMax) {
+	    /*
+	     * Set the variables and jump back to run the body
+	     */
+
+	    tmpPtr->internalRep.twoPtrValue.ptr1 = INT2PTR(iterNum + 1);
+
+	    listTmpDepth = numLists + 1;
+
+	    for (i = 0;  i < numLists;  i++) {
+		varListPtr = infoPtr->varLists[i];
+		numVars = varListPtr->numVars;
+
+		listPtr = OBJ_AT_DEPTH(listTmpDepth);
+		TclListObjGetElements(interp, listPtr, &listLen, &elements);
+
+		valIndex = (iterNum * numVars);
+		for (j = 0;  j < numVars;  j++) {
+		    if (valIndex >= listLen) {
+			TclNewObj(valuePtr);
+		    } else {
+			valuePtr = elements[valIndex];
+		    }
+
+		    varIndex = varListPtr->varIndexes[j];
+		    varPtr = LOCAL(varIndex);
+		    while (TclIsVarLink(varPtr)) {
+			varPtr = varPtr->value.linkPtr;
+		    }
+		    if (TclIsVarDirectWritable(varPtr)) {
+			value2Ptr = varPtr->value.objPtr;
+			if (valuePtr != value2Ptr) {
+			    if (value2Ptr != NULL) {
+				TclDecrRefCount(value2Ptr);
+			    }
+			    varPtr->value.objPtr = valuePtr;
+			    Tcl_IncrRefCount(valuePtr);
+			}
+		    } else {
+			DECACHE_STACK_INFO();
+			if (TclPtrSetVar(interp, varPtr, NULL, NULL, NULL,
+				valuePtr, TCL_LEAVE_ERR_MSG, varIndex)==NULL){
+			    CACHE_STACK_INFO();
+			    TRACE_APPEND(("ERROR init. index temp %d: %.30s",
+				    varIndex, O2S(Tcl_GetObjResult(interp))));
+			    goto gotError;
+			}
+			CACHE_STACK_INFO();
+		    }
+		    valIndex++;
+		}
+		listTmpDepth--;
+	    }
+	    TRACE_APPEND(("jump to loop start\n"));
+	    /* loopCtTemp being 'misused' for storing the jump size */
+	    NEXT_INST_F(infoPtr->loopCtTemp, 0, 0);
+	}
+
+	TRACE_APPEND(("loop has no more iterations\n"));
+#ifdef TCL_COMPILE_DEBUG
+	NEXT_INST_F(1, 0, 0);
+#else
+	/*
+	 * FALL THROUGH
+	 */
+	pc++;
+#endif
+
+    case INST_FOREACH_END:
+	/* THIS INSTRUCTION IS ONLY CALLED AS A BREAK TARGET */
+	tmpPtr = OBJ_AT_TOS;
+	infoPtr = tmpPtr->internalRep.otherValuePtr;
+	numLists = infoPtr->numLists;
+	TRACE(("=> loop terminated\n"));
+	NEXT_INST_V(1, numLists+2, 0);
+
+    case INST_LMAP_COLLECT:
+	/*
+	 * This instruction is only issued by lmap. The stack is:
+	 *   - result
+	 *   - infoPtr
+	 *   - loop counters
+	 *   - valLists
+	 *   - collecting obj (unshared)
+	 * The instruction lappends the result to the collecting obj.
+	 */
+
+	tmpPtr = OBJ_AT_DEPTH(1);
+	infoPtr = tmpPtr->internalRep.otherValuePtr;
+	numLists = infoPtr->numLists;
+	TRACE_APPEND(("=> appending to list at depth %d\n", 3 + numLists));
+	
+	objPtr = OBJ_AT_DEPTH(3 + numLists);
+	Tcl_ListObjAppendElement(NULL, objPtr, OBJ_AT_TOS);
+	NEXT_INST_F(1, 1, 0);
     }
 
     case INST_BEGIN_CATCH4:
@@ -6241,7 +7120,8 @@ TEBCresume(
 	if (code < TCL_ERROR || code > TCL_CONTINUE) {
 	    code = TCL_CONTINUE + 1;
 	}
-	NEXT_INST_F(2*code -1, 1, 0);
+	TRACE(("\"%s\" => jump offset %d\n", O2S(OBJ_AT_TOS), 2*code-1));
+	NEXT_INST_F(2*code-1, 1, 0);
     }
 
     /*
@@ -6258,10 +7138,10 @@ TEBCresume(
 
     case INST_DICT_VERIFY:
 	dictPtr = OBJ_AT_TOS;
-	TRACE(("=> "));
+	TRACE(("\"%.30s\" => ", O2S(dictPtr)));
 	if (Tcl_DictObjSize(interp, dictPtr, &done) != TCL_OK) {
-	    TRACE_APPEND(("ERROR verifying dictionary nature of \"%s\": %s\n",
-		    O2S(OBJ_AT_DEPTH(opnd)), O2S(Tcl_GetObjResult(interp))));
+	    TRACE_APPEND(("ERROR verifying dictionary nature of \"%.30s\": %s\n",
+		    O2S(dictPtr), O2S(Tcl_GetObjResult(interp))));
 	    goto gotError;
 	}
 	TRACE_APPEND(("OK\n"));
@@ -6270,6 +7150,7 @@ TEBCresume(
     case INST_DICT_GET:
     case INST_DICT_EXISTS: {
 	register Tcl_Interp *interp2 = interp;
+	register int found;
 
 	opnd = TclGetUInt4AtPtr(pc+1);
 	TRACE(("%u => ", opnd));
@@ -6282,10 +7163,11 @@ TEBCresume(
 		    &OBJ_AT_DEPTH(opnd-1), DICT_PATH_READ);
 	    if (dictPtr == NULL) {
 		if (*pc == INST_DICT_EXISTS) {
-		    goto dictNotExists;
+		    found = 0;
+		    goto afterDictExists;
 		}
 		TRACE_WITH_OBJ((
-			"ERROR tracing dictionary path into \"%s\": ",
+			"ERROR tracing dictionary path into \"%.30s\": ",
 			O2S(OBJ_AT_DEPTH(opnd))),
 			Tcl_GetObjResult(interp));
 		goto gotError;
@@ -6294,34 +7176,40 @@ TEBCresume(
 	if (Tcl_DictObjGet(interp2, dictPtr, OBJ_AT_TOS,
 		&objResultPtr) == TCL_OK) {
 	    if (*pc == INST_DICT_EXISTS) {
-		objResultPtr = TCONST(objResultPtr ? 1 : 0);
-		TRACE_APPEND(("%.30s\n", O2S(objResultPtr)));
-		NEXT_INST_V(5, opnd+1, 1);
+		found = (objResultPtr ? 1 : 0);
+		goto afterDictExists;
 	    }
-	    if (objResultPtr) {
-		TRACE_APPEND(("%.30s\n", O2S(objResultPtr)));
-		NEXT_INST_V(5, opnd+1, 1);
+	    if (!objResultPtr) {
+		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			"key \"%s\" not known in dictionary",
+			TclGetString(OBJ_AT_TOS)));
+		DECACHE_STACK_INFO();
+		Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "DICT",
+			TclGetString(OBJ_AT_TOS), NULL);
+		CACHE_STACK_INFO();
+		TRACE_ERROR(interp);
+		goto gotError;
 	    }
-	    DECACHE_STACK_INFO();
-	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
-		    "key \"%s\" not known in dictionary",
-		    TclGetString(OBJ_AT_TOS)));
-	    Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "DICT",
-		    TclGetString(OBJ_AT_TOS), NULL);
-	    CACHE_STACK_INFO();
-	    TRACE_WITH_OBJ(("%u => ERROR ", opnd), Tcl_GetObjResult(interp));
+	    TRACE_APPEND(("%.30s\n", O2S(objResultPtr)));
+	    NEXT_INST_V(5, opnd+1, 1);
+	} else if (*pc != INST_DICT_EXISTS) {
+	    TRACE_APPEND(("ERROR reading leaf dictionary key \"%.30s\": %s",
+		    O2S(dictPtr), O2S(Tcl_GetObjResult(interp))));
+	    goto gotError;
 	} else {
-	    if (*pc == INST_DICT_EXISTS) {
-	    dictNotExists:
-		objResultPtr = TCONST(0);
-		TRACE_APPEND(("%.30s\n", O2S(objResultPtr)));
-		NEXT_INST_V(5, opnd+1, 1);
-	    }
-	    TRACE_WITH_OBJ((
-		    "%u => ERROR reading leaf dictionary key \"%s\": ",
-		    opnd, O2S(dictPtr)), Tcl_GetObjResult(interp));
+	    found = 0;
 	}
-	goto gotError;
+    afterDictExists:
+	TRACE_APPEND(("%d\n", found));
+
+	/*
+	 * The INST_DICT_EXISTS instruction is usually followed by a
+	 * conditional jump, so we can take advantage of this to do some
+	 * peephole optimization (note that we're careful to not close out
+	 * someone doing something else).
+	 */
+
+	JUMP_PEEPHOLE_V(found, 5, opnd+1);
     }
 
     case INST_DICT_SET:
@@ -6395,8 +7283,8 @@ TEBCresume(
 	    if (allocateDict) {
 		TclDecrRefCount(dictPtr);
 	    }
-	    TRACE_WITH_OBJ(("%u %u => ERROR updating dictionary: ",
-		    opnd, opnd2), Tcl_GetObjResult(interp));
+	    TRACE_APPEND(("ERROR updating dictionary: %s\n",
+		    O2S(Tcl_GetObjResult(interp))));
 	    goto checkForCatch;
 	}
 
@@ -6418,8 +7306,7 @@ TEBCresume(
 	    CACHE_STACK_INFO();
 	    TclDecrRefCount(dictPtr);
 	    if (objResultPtr == NULL) {
-		TRACE_APPEND(("ERROR: %.30s\n",
-			O2S(Tcl_GetObjResult(interp))));
+		TRACE_ERROR(interp);
 		goto gotError;
 	    }
 	}
@@ -6428,7 +7315,7 @@ TEBCresume(
 	    NEXT_INST_V(10, cleanup, 0);
 	}
 #endif
-	TRACE_APPEND(("%.30s\n", O2S(objResultPtr)));
+	TRACE_APPEND(("\"%.30s\"\n", O2S(objResultPtr)));
 	NEXT_INST_V(9, cleanup, 1);
 
     case INST_DICT_APPEND:
@@ -6461,6 +7348,7 @@ TEBCresume(
 	    if (allocateDict) {
 		TclDecrRefCount(dictPtr);
 	    }
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 
@@ -6509,6 +7397,7 @@ TEBCresume(
 		    if (allocateDict) {
 			TclDecrRefCount(dictPtr);
 		    }
+		    TRACE_ERROR(interp);
 		    goto gotError;
 		}
 		Tcl_DictObjPut(NULL, dictPtr, OBJ_UNDER_TOS, valuePtr);
@@ -6518,6 +7407,7 @@ TEBCresume(
 		    if (allocateDict) {
 			TclDecrRefCount(dictPtr);
 		    }
+		    TRACE_ERROR(interp);
 		    goto gotError;
 		}
 
@@ -6554,8 +7444,7 @@ TEBCresume(
 	    CACHE_STACK_INFO();
 	    TclDecrRefCount(dictPtr);
 	    if (objResultPtr == NULL) {
-		TRACE_APPEND(("ERROR: %.30s\n",
-			O2S(Tcl_GetObjResult(interp))));
+		TRACE_ERROR(interp);
 		goto gotError;
 	    }
 	}
@@ -6575,6 +7464,7 @@ TEBCresume(
 	if (Tcl_DictObjFirst(interp, dictPtr, searchPtr, &keyPtr,
 		&valuePtr, &done) != TCL_OK) {
 	    ckfree(searchPtr);
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 	TclNewObj(statePtr);
@@ -6610,8 +7500,9 @@ TEBCresume(
 	    PUSH_OBJECT(valuePtr);
 	    PUSH_OBJECT(keyPtr);
 	}
+	TRACE_APPEND(("\"%.30s\" \"%.30s\" %d\n",
+		O2S(OBJ_UNDER_TOS), O2S(OBJ_AT_TOS), done));
 
-#ifndef TCL_COMPILE_DEBUG
 	/*
 	 * The INST_DICT_FIRST and INST_DICT_NEXT instructsions are always
 	 * followed by a conditional jump, so we can take advantage of this to
@@ -6619,37 +7510,17 @@ TEBCresume(
 	 * out someone doing something else).
 	 */
 
-	pc += 5;
-	switch (*pc) {
-	case INST_JUMP_FALSE1:
-	    NEXT_INST_F((done ? 2 : TclGetInt1AtPtr(pc+1)), 0, 0);
-	case INST_JUMP_FALSE4:
-	    NEXT_INST_F((done ? 5 : TclGetInt4AtPtr(pc+1)), 0, 0);
-	case INST_JUMP_TRUE1:
-	    NEXT_INST_F((done ? TclGetInt1AtPtr(pc+1) : 2), 0, 0);
-	case INST_JUMP_TRUE4:
-	    NEXT_INST_F((done ? TclGetInt4AtPtr(pc+1) : 5), 0, 0);
-	default:
-	    pc -= 5;
-	    /* fall through to non-debug handling */
-	}
-#endif
-
-	TRACE_APPEND(("\"%.30s\" \"%.30s\" %d\n",
-		O2S(OBJ_UNDER_TOS), O2S(OBJ_AT_TOS), done));
-	objResultPtr = TCONST(done);
-	/* TODO: consider opt like INST_FOREACH_STEP4 */
-	NEXT_INST_F(5, 0, 1);
+	JUMP_PEEPHOLE_F(done, 5, 0);
 
     case INST_DICT_UPDATE_START:
 	opnd = TclGetUInt4AtPtr(pc+1);
 	opnd2 = TclGetUInt4AtPtr(pc+5);
+	TRACE(("%u => ", opnd));
 	varPtr = LOCAL(opnd);
 	duiPtr = codePtr->auxDataArrayPtr[opnd2].clientData;
 	while (TclIsVarLink(varPtr)) {
 	    varPtr = varPtr->value.linkPtr;
 	}
-	TRACE(("%u => \n", opnd));
 	if (TclIsVarDirectReadable(varPtr)) {
 	    dictPtr = varPtr->value.objPtr;
 	} else {
@@ -6658,11 +7529,13 @@ TEBCresume(
 		    TCL_LEAVE_ERR_MSG, opnd);
 	    CACHE_STACK_INFO();
 	    if (dictPtr == NULL) {
+		TRACE_ERROR(interp);
 		goto gotError;
 	    }
 	}
 	if (TclListObjGetElements(interp, OBJ_AT_TOS, &length,
 		&keyPtrPtr) != TCL_OK) {
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 	if (length != duiPtr->length) {
@@ -6671,6 +7544,7 @@ TEBCresume(
 	for (i=0 ; i<length ; i++) {
 	    if (Tcl_DictObjGet(interp, dictPtr, keyPtrPtr[i],
 		    &valuePtr) != TCL_OK) {
+		TRACE_ERROR(interp);
 		goto gotError;
 	    }
 	    varPtr = LOCAL(duiPtr->varIndices[i]);
@@ -6686,21 +7560,23 @@ TEBCresume(
 		    valuePtr, TCL_LEAVE_ERR_MSG,
 		    duiPtr->varIndices[i]) == NULL) {
 		CACHE_STACK_INFO();
+		TRACE_ERROR(interp);
 		goto gotError;
 	    }
 	    CACHE_STACK_INFO();
 	}
+	TRACE_APPEND(("OK\n"));
 	NEXT_INST_F(9, 0, 0);
 
     case INST_DICT_UPDATE_END:
 	opnd = TclGetUInt4AtPtr(pc+1);
 	opnd2 = TclGetUInt4AtPtr(pc+5);
+	TRACE(("%u => ", opnd));
 	varPtr = LOCAL(opnd);
 	duiPtr = codePtr->auxDataArrayPtr[opnd2].clientData;
 	while (TclIsVarLink(varPtr)) {
 	    varPtr = varPtr->value.linkPtr;
 	}
-	TRACE(("%u => ", opnd));
 	if (TclIsVarDirectReadable(varPtr)) {
 	    dictPtr = varPtr->value.objPtr;
 	} else {
@@ -6709,11 +7585,13 @@ TEBCresume(
 	    CACHE_STACK_INFO();
 	}
 	if (dictPtr == NULL) {
+	    TRACE_APPEND(("storage was unset\n"));
 	    NEXT_INST_F(9, 1, 0);
 	}
 	if (Tcl_DictObjSize(interp, dictPtr, &length) != TCL_OK
 		|| TclListObjGetElements(interp, OBJ_AT_TOS, &length,
 			&keyPtrPtr) != TCL_OK) {
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 	allocdict = Tcl_IsShared(dictPtr);
@@ -6759,27 +7637,27 @@ TEBCresume(
 		if (allocdict) {
 		    TclDecrRefCount(dictPtr);
 		}
+		TRACE_ERROR(interp);
 		goto gotError;
 	    }
 	}
+	TRACE_APPEND(("written back\n"));
 	NEXT_INST_F(9, 1, 0);
 
     case INST_DICT_EXPAND:
 	dictPtr = OBJ_UNDER_TOS;
 	listPtr = OBJ_AT_TOS;
+	TRACE(("\"%.30s\" \"%.30s\" =>", O2S(dictPtr), O2S(listPtr)));
 	if (TclListObjGetElements(interp, listPtr, &objc, &objv) != TCL_OK) {
-	    TRACE_WITH_OBJ(("%.30s %.30s => ERROR: ",
-		    O2S(dictPtr), O2S(listPtr)), Tcl_GetObjResult(interp));
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 	objResultPtr = TclDictWithInit(interp, dictPtr, objc, objv);
 	if (objResultPtr == NULL) {
-	    TRACE_WITH_OBJ(("%.30s %.30s => ERROR: ",
-		    O2S(dictPtr), O2S(listPtr)), Tcl_GetObjResult(interp));
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
-	TRACE((" => "));
-	TRACE_APPEND(("%.30s\n", O2S(objResultPtr)));
+	TRACE_APPEND(("\"%.30s\"\n", O2S(objResultPtr)));
 	NEXT_INST_F(1, 2, 1);
 
     case INST_DICT_RECOMBINE_STK:
@@ -6789,14 +7667,14 @@ TEBCresume(
 	TRACE(("\"%.30s\" \"%.30s\" \"%.30s\" => ",
 		O2S(varNamePtr), O2S(valuePtr), O2S(keysPtr)));
 	if (TclListObjGetElements(interp, listPtr, &objc, &objv) != TCL_OK) {
-	    TRACE_APPEND(("ERROR: %.30s\n", O2S(Tcl_GetObjResult(interp))));
+	    TRACE_ERROR(interp);
 	    TclDecrRefCount(keysPtr);
 	    goto gotError;
 	}
 	varPtr = TclObjLookupVarEx(interp, varNamePtr, NULL,
 		TCL_LEAVE_ERR_MSG, "set", 1, 1, &arrayPtr);
 	if (varPtr == NULL) {
-	    TRACE_APPEND(("ERROR: %.30s\n", O2S(Tcl_GetObjResult(interp))));
+	    TRACE_ERROR(interp);
 	    TclDecrRefCount(keysPtr);
 	    goto gotError;
 	}
@@ -6806,7 +7684,7 @@ TEBCresume(
 	CACHE_STACK_INFO();
 	TclDecrRefCount(keysPtr);
 	if (result != TCL_OK) {
-	    TRACE_APPEND(("ERROR: %.30s\n", O2S(Tcl_GetObjResult(interp))));
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 	TRACE_APPEND(("OK\n"));
@@ -6820,7 +7698,7 @@ TEBCresume(
 	TRACE(("%u <- \"%.30s\" \"%.30s\" => ", opnd, O2S(valuePtr),
 		O2S(keysPtr)));
 	if (TclListObjGetElements(interp, listPtr, &objc, &objv) != TCL_OK) {
-	    TRACE_APPEND(("ERROR: %.30s\n", O2S(Tcl_GetObjResult(interp))));
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 	while (TclIsVarLink(varPtr)) {
@@ -6831,7 +7709,7 @@ TEBCresume(
 		objc, objv, keysPtr);
 	CACHE_STACK_INFO();
 	if (result != TCL_OK) {
-	    TRACE_APPEND(("ERROR: %.30s\n", O2S(Tcl_GetObjResult(interp))));
+	    TRACE_ERROR(interp);
 	    goto gotError;
 	}
 	TRACE_APPEND(("OK\n"));
@@ -6927,10 +7805,10 @@ TEBCresume(
 	if (traceInstructions) {
 	    objPtr = Tcl_GetObjResult(interp);
 	    if ((result != TCL_ERROR) && (result != TCL_RETURN)) {
-		TRACE_APPEND(("OTHER RETURN CODE %d, result= \"%s\"\n ",
+		TRACE_APPEND(("OTHER RETURN CODE %d, result=\"%.30s\"\n ",
 			result, O2S(objPtr)));
 	    } else {
-		TRACE_APPEND(("%s, result= \"%s\"\n",
+		TRACE_APPEND(("%s, result=\"%.30s\"\n",
 			StringForResultCode(result), O2S(objPtr)));
 	    }
 	}
@@ -6943,8 +7821,8 @@ TEBCresume(
 	 */
 
     divideByZero:
-	DECACHE_STACK_INFO();
 	Tcl_SetObjResult(interp, Tcl_NewStringObj("divide by zero", -1));
+	DECACHE_STACK_INFO();
 	Tcl_SetErrorCode(interp, "ARITH", "DIVZERO", "divide by zero", NULL);
 	CACHE_STACK_INFO();
 	goto gotError;
@@ -6955,9 +7833,9 @@ TEBCresume(
 	 */
 
     exponOfZero:
-	DECACHE_STACK_INFO();
 	Tcl_SetObjResult(interp, Tcl_NewStringObj(
 		"exponentiation of zero by negative power", -1));
+	DECACHE_STACK_INFO();
 	Tcl_SetErrorCode(interp, "ARITH", "DOMAIN",
 		"exponentiation of zero by negative power", NULL);
 	CACHE_STACK_INFO();
@@ -7183,6 +8061,58 @@ TEBCresume(
 #undef auxObjList
 #undef catchTop
 #undef TCONST
+
+static int
+FinalizeOONext(
+    ClientData data[],
+    Tcl_Interp *interp,
+    int result)
+{
+    Interp *iPtr = (Interp *) interp;
+    CallContext *contextPtr = data[1];
+
+    /*
+     * Reset the variable lookup frame.
+     */
+
+    iPtr->varFramePtr = data[0];
+
+    /*
+     * Restore the call chain context index as we've finished the inner invoke
+     * and want to operate in the outer context again.
+     */
+
+    contextPtr->index = PTR2INT(data[2]);
+    contextPtr->skip = PTR2INT(data[3]);
+    contextPtr->oPtr->flags &= ~FILTER_HANDLING;
+    return result;
+}
+
+static int
+FinalizeOONextFilter(
+    ClientData data[],
+    Tcl_Interp *interp,
+    int result)
+{
+    Interp *iPtr = (Interp *) interp;
+    CallContext *contextPtr = data[1];
+
+    /*
+     * Reset the variable lookup frame.
+     */
+
+    iPtr->varFramePtr = data[0];
+
+    /*
+     * Restore the call chain context index as we've finished the inner invoke
+     * and want to operate in the outer context again.
+     */
+
+    contextPtr->index = PTR2INT(data[2]);
+    contextPtr->skip = PTR2INT(data[3]);
+    contextPtr->oPtr->flags |= FILTER_HANDLING;
+    return result;
+}
 
 /*
  *----------------------------------------------------------------------
@@ -8710,10 +9640,12 @@ IllegalExprOperandType(
     ClientData ptr;
     int type;
     const unsigned char opcode = *pc;
-    const char *description, *operator = operatorStrings[opcode - INST_LOR];
+    const char *description, *operator = "unknown";
 
     if (opcode == INST_EXPON) {
 	operator = "**";
+    } else if (opcode <= INST_STR_NEQ) {
+	operator = operatorStrings[opcode - INST_LOR];
     }
 
     if (GetNumberFromObj(NULL, opndPtr, &ptr, &type) != TCL_OK) {
diff --git a/generic/tclFCmd.c b/generic/tclFCmd.c
index 13377d3..6452fff 100644
--- a/generic/tclFCmd.c
+++ b/generic/tclFCmd.c
@@ -517,7 +517,7 @@ CopyRenameOneFile(
 	 * 16 bits and we get collisions. See bug #2015723.
 	 */
 
-#if !defined(WIN32) && !defined(__CYGWIN__)
+#if !defined(_WIN32) && !defined(__CYGWIN__)
 	if ((sourceStatBuf.st_ino != 0) && (targetStatBuf.st_ino != 0)) {
 	    if ((sourceStatBuf.st_ino == targetStatBuf.st_ino) &&
 		    (sourceStatBuf.st_dev == targetStatBuf.st_dev)) {
diff --git a/generic/tclIO.c b/generic/tclIO.c
index f1d85bf..ff975c3 100644
--- a/generic/tclIO.c
+++ b/generic/tclIO.c
@@ -165,8 +165,6 @@ static ChannelBuffer *	AllocChannelBuffer(int length);
 static void		ChannelTimerProc(ClientData clientData);
 static int		CheckChannelErrors(ChannelState *statePtr,
 			    int direction);
-static int		CheckFlush(Channel *chanPtr, ChannelBuffer *bufPtr,
-			    int newlineFlag);
 static int		CheckForDeadChannel(Tcl_Interp *interp,
 			    ChannelState *statePtr);
 static void		CheckForStdChannelsBeingClosed(Tcl_Channel chan);
@@ -194,15 +192,14 @@ static void		DiscardInputQueued(ChannelState *statePtr,
 			    int discardSavedBuffers);
 static void		DiscardOutputQueued(ChannelState *chanPtr);
 static int		DoRead(Channel *chanPtr, char *srcPtr, int slen, int allowShortReads);
-static int		DoWrite(Channel *chanPtr, const char *src, int srcLen);
 static int		DoReadChars(Channel *chan, Tcl_Obj *objPtr, int toRead,
 			    int appendFlag);
-static int		DoWriteChars(Channel *chan, const char *src, int len);
 static int		FilterInputBytes(Channel *chanPtr,
 			    GetsState *statePtr);
 static int		FlushChannel(Tcl_Interp *interp, Channel *chanPtr,
 			    int calledFromAsyncFlush);
 static int		TclGetsObjBinary(Tcl_Channel chan, Tcl_Obj *objPtr);
+static Tcl_Encoding	GetBinaryEncoding();
 static void		FreeBinaryEncoding(ClientData clientData);
 static Tcl_HashTable *	GetChannelTable(Tcl_Interp *interp);
 static int		GetInput(Channel *chanPtr);
@@ -222,18 +219,19 @@ static int		SetBlockMode(Tcl_Interp *interp, Channel *chanPtr,
 static void		StopCopy(CopyState *csPtr);
 static int		TranslateInputEOL(ChannelState *statePtr, char *dst,
 			    const char *src, int *dstLenPtr, int *srcLenPtr);
-static int		TranslateOutputEOL(ChannelState *statePtr, char *dst,
-			    const char *src, int *dstLenPtr, int *srcLenPtr);
 static void		UpdateInterest(Channel *chanPtr);
-static int		WriteBytes(Channel *chanPtr, const char *src,
-			    int srcLen);
-static int		WriteChars(Channel *chanPtr, const char *src,
-			    int srcLen);
+static int		Write(Channel *chanPtr, const char *src,
+			    int srcLen, Tcl_Encoding encoding);
 static Tcl_Obj *	FixLevelCode(Tcl_Obj *msg);
 static void		SpliceChannel(Tcl_Channel chan);
 static void		CutChannel(Tcl_Channel chan);
 static int              WillRead(Channel *chanPtr);
 
+#define WriteChars(chanPtr, src, srcLen) \
+			Write(chanPtr, src, srcLen, chanPtr->state->encoding)
+#define WriteBytes(chanPtr, src, srcLen) \
+			Write(chanPtr, src, srcLen, tclIdentityEncoding)
+
 /*
  * Simplifying helper macros. All may use their argument(s) multiple times.
  * The ANSI C "prototypes" for the macros are listed below, together with a
@@ -323,14 +321,13 @@ static int              WillRead(Channel *chanPtr);
 static void		DupChannelIntRep(Tcl_Obj *objPtr, Tcl_Obj *copyPtr);
 static int		SetChannelFromAny(Tcl_Interp *interp,
 			    Tcl_Obj *objPtr);
-static void		UpdateStringOfChannel(Tcl_Obj *objPtr);
 static void		FreeChannelIntRep(Tcl_Obj *objPtr);
 
-static const Tcl_ObjType tclChannelType = {
+static const Tcl_ObjType chanObjType = {
     "channel",			/* name for this type */
     FreeChannelIntRep,		/* freeIntRepProc */
     DupChannelIntRep,		/* dupIntRepProc */
-    NULL,			/* updateStringProc UpdateStringOfChannel */
+    NULL,			/* updateStringProc */
     NULL			/* setFromAnyProc SetChannelFromAny */
 };
 
@@ -339,7 +336,7 @@ static const Tcl_ObjType tclChannelType = {
 #define SET_CHANNELSTATE(objPtr, storePtr) \
     ((objPtr)->internalRep.twoPtrValue.ptr1 = (void *) (storePtr))
 #define GET_CHANNELINTERP(objPtr) \
-    ((Interp *) (objPtr)->internalRep.twoPtrValue.ptr2)
+    ((Tcl_Interp *) (objPtr)->internalRep.twoPtrValue.ptr2)
 #define SET_CHANNELINTERP(objPtr, storePtr) \
     ((objPtr)->internalRep.twoPtrValue.ptr2 = (void *) (storePtr))
 
@@ -1581,11 +1578,7 @@ Tcl_CreateChannel(
     statePtr->timer		= NULL;
     statePtr->csPtrR		= NULL;
     statePtr->csPtrW		= NULL;
-
     statePtr->outputStage	= NULL;
-    if ((statePtr->encoding != NULL) && GotFlag(statePtr, TCL_WRITABLE)) {
-	statePtr->outputStage = ckalloc(statePtr->bufSize + 2);
-    }
 
     /*
      * As we are creating the channel, it is obviously the top for now.
@@ -2838,10 +2831,6 @@ CloseChannel(
 	}
 
 	Tcl_FreeEncoding(statePtr->encoding);
-	if (statePtr->outputStage != NULL) {
-	    ckfree(statePtr->outputStage);
-	    statePtr->outputStage = NULL;
-	}
     }
 
     /*
@@ -3778,7 +3767,7 @@ Tcl_Write(
     if (srcLen < 0) {
 	srcLen = strlen(src);
     }
-    return DoWrite(chanPtr, src, srcLen);
+    return WriteBytes(chanPtr, src, srcLen);
 }
 
 /*
@@ -3869,82 +3858,40 @@ Tcl_WriteChars(
     int len)			/* Length of string in bytes, or < 0 for
 				 * strlen(). */
 {
-    ChannelState *statePtr;	/* State info for channel */
-
-    statePtr = ((Channel *) chan)->state;
+    Channel *chanPtr = (Channel *) chan;
+    ChannelState *statePtr = chanPtr->state;	/* State info for channel */
+    int result;
+    Tcl_Obj *objPtr;
 
     if (CheckChannelErrors(statePtr, TCL_WRITABLE) != 0) {
 	return -1;
     }
 
-    return DoWriteChars((Channel *) chan, src, len);
-}
-
-/*
- *---------------------------------------------------------------------------
- *
- * DoWriteChars --
- *
- *	Takes a sequence of UTF-8 characters and converts them for output
- *	using the channel's current encoding, may queue the buffer for output
- *	if it gets full, and also remembers whether the current buffer is
- *	ready e.g. if it contains a newline and we are in line buffering mode.
- *	Compensates stacking, i.e. will redirect the data from the specified
- *	channel to the topmost channel in a stack.
- *
- * Results:
- *	The number of bytes written or -1 in case of error. If -1,
- *	Tcl_GetErrno will return the error code.
- *
- * Side effects:
- *	May buffer up output and may cause output to be produced on the
- *	channel.
- *
- *----------------------------------------------------------------------
- */
-
-static int
-DoWriteChars(
-    Channel *chanPtr,		/* The channel to buffer output for. */
-    const char *src,		/* UTF-8 characters to queue in output
-				 * buffer. */
-    int len)			/* Length of string in bytes, or < 0 for
-				 * strlen(). */
-{
-    /*
-     * Always use the topmost channel of the stack
-     */
-
-    ChannelState *statePtr;	/* State info for channel */
-
-    statePtr = chanPtr->state;
     chanPtr = statePtr->topChanPtr;
 
     if (len < 0) {
 	len = strlen(src);
     }
-    if (statePtr->encoding == NULL) {
-	/*
-	 * Inefficient way to convert UTF-8 to byte-array, but the code
-	 * parallels the way it is done for objects.
-	 * Special case for 1-byte (used by eg [puts] for the \n) could
-	 * be extended to more efficient translation of the src string.
-	 */
-
-	int result;
+    if (statePtr->encoding) {
+	return WriteChars(chanPtr, src, len);
+    }
 
-	if ((len == 1) && (UCHAR(*src) < 0xC0)) {
-	    result = WriteBytes(chanPtr, src, len);
-	} else {
-	    Tcl_Obj *objPtr = Tcl_NewStringObj(src, len);
+    /*
+     * Inefficient way to convert UTF-8 to byte-array, but the code
+     * parallels the way it is done for objects.  Special case for 1-byte
+     * (used by eg [puts] for the \n) could be extended to more efficient
+     * translation of the src string.
+     */
 
-	    src = (char *) Tcl_GetByteArrayFromObj(objPtr, &len);
-	    result = WriteBytes(chanPtr, src, len);
-	    TclDecrRefCount(objPtr);
-	}
-	return result;
+    if ((len == 1) && (UCHAR(*src) < 0xC0)) {
+	return WriteBytes(chanPtr, src, len);
     }
-    return WriteChars(chanPtr, src, len);
+
+    objPtr = Tcl_NewStringObj(src, len);
+    src = (char *) Tcl_GetByteArrayFromObj(objPtr, &len);
+    result = WriteBytes(chanPtr, src, len);
+    TclDecrRefCount(objPtr);
+    return result;
 }
 
 /*
@@ -4036,110 +3983,9 @@ WillRead(
 /*
  *----------------------------------------------------------------------
  *
- * WriteBytes --
- *
- *	Write a sequence of bytes into an output buffer, may queue the buffer
- *	for output if it gets full, and also remembers whether the current
- *	buffer is ready e.g. if it contains a newline and we are in line
- *	buffering mode.
- *
- * Results:
- *	The number of bytes written or -1 in case of error. If -1,
- *	Tcl_GetErrno will return the error code.
+ * Write --
  *
- * Side effects:
- *	May buffer up output and may cause output to be produced on the
- *	channel.
- *
- *----------------------------------------------------------------------
- */
-
-static int
-WriteBytes(
-    Channel *chanPtr,		/* The channel to buffer output for. */
-    const char *src,		/* Bytes to write. */
-    int srcLen)			/* Number of bytes to write. */
-{
-    ChannelState *statePtr = chanPtr->state;
-				/* State info for channel */
-    ChannelBuffer *bufPtr;
-    char *dst;
-    int dstMax, sawLF, savedLF, total, dstLen, toWrite, translate;
-
-    if (srcLen) {
-        WillWrite(chanPtr);
-    }
-
-    total = 0;
-    sawLF = 0;
-    savedLF = 0;
-    translate = GotFlag(statePtr, CHANNEL_LINEBUFFERED)
-	    || (statePtr->outputTranslation != TCL_TRANSLATE_LF);
-
-    /*
-     * Loop over all bytes in src, storing them in output buffer with proper
-     * EOL translation.
-     */
-
-    while (srcLen + savedLF > 0) {
-	bufPtr = statePtr->curOutPtr;
-	if (bufPtr == NULL) {
-	    bufPtr = AllocChannelBuffer(statePtr->bufSize);
-	    statePtr->curOutPtr = bufPtr;
-	}
-	dst = InsertPoint(bufPtr);
-	dstMax = SpaceLeft(bufPtr);
-	dstLen = dstMax;
-
-	toWrite = dstLen;
-	if (toWrite > srcLen) {
-	    toWrite = srcLen;
-	}
-
-	if (translate) {
-	    if (savedLF) {
-		/*
-		 * A '\n' was left over from last call to TranslateOutputEOL()
-		 * and we need to store it in this buffer. If the channel is
-		 * line-based, we will need to flush it.
-		 */
-
-		*dst++ = '\n';
-		dstLen--;
-		sawLF++;
-	    }
-	    if (TranslateOutputEOL(statePtr, dst, src, &dstLen, &toWrite)) {
-		sawLF++;
-	    }
-	    dstLen += savedLF;
-	    savedLF = 0;
-	    if (dstLen > dstMax) {
-		savedLF = 1;
-		dstLen = dstMax;
-	    }
-	} else {
-	    memcpy(dst, src, toWrite);
-	    dstLen = toWrite;
-	}
-
-	bufPtr->nextAdded += dstLen;
-	if (CheckFlush(chanPtr, bufPtr, sawLF) != 0) {
-	    return -1;
-	}
-	total += dstLen;
-	src += toWrite;
-	srcLen -= toWrite;
-	sawLF = 0;
-    }
-    return total;
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * WriteChars --
- *
- *	Convert UTF-8 bytes to the channel's external encoding and write the
+ *	Convert srcLen bytes starting at src according to encoding and write
  *	produced bytes into an output buffer, may queue the buffer for output
  *	if it gets full, and also remembers whether the current buffer is
  *	ready e.g. if it contains a newline and we are in line buffering mode.
@@ -4156,381 +4002,163 @@ WriteBytes(
  */
 
 static int
-WriteChars(
+Write(
     Channel *chanPtr,		/* The channel to buffer output for. */
     const char *src,		/* UTF-8 string to write. */
-    int srcLen)			/* Length of UTF-8 string in bytes. */
+    int srcLen,			/* Length of UTF-8 string in bytes. */
+    Tcl_Encoding encoding)
 {
     ChannelState *statePtr = chanPtr->state;
 				/* State info for channel */
-    ChannelBuffer *bufPtr;
-    char *dst, *stage;
-    int saved, savedLF, sawLF, total, dstLen, stageMax, dstWrote;
-    int stageLen, toWrite, stageRead, endEncoding, result;
-    int consumedSomething, translate;
-    Tcl_Encoding encoding;
-    char safe[BUFFER_PADDING];
+    char *nextNewLine = NULL;
+    int endEncoding, saved = 0, total = 0, flushed = 0, needNlFlush = 0;
 
     if (srcLen) {
         WillWrite(chanPtr);
     }
 
-    total = 0;
-    sawLF = 0;
-    savedLF = 0;
-    saved = 0;
-    encoding = statePtr->encoding;
-
     /*
      * Write the terminated escape sequence even if srcLen is 0.
      */
 
     endEncoding = ((statePtr->outputEncodingFlags & TCL_ENCODING_END) != 0);
 
-    translate = GotFlag(statePtr, CHANNEL_LINEBUFFERED)
-	    || (statePtr->outputTranslation != TCL_TRANSLATE_LF);
-
-    /*
-     * Loop over all UTF-8 characters in src, storing them in staging buffer
-     * with proper EOL translation.
-     */
+    if (GotFlag(statePtr, CHANNEL_LINEBUFFERED)
+	    || (statePtr->outputTranslation != TCL_TRANSLATE_LF)) {
+	nextNewLine = memchr(src, '\n', srcLen);
+    }
 
-    consumedSomething = 1;
-    while (consumedSomething && (srcLen + savedLF + endEncoding > 0)) {
-	consumedSomething = 0;
-	stage = statePtr->outputStage;
-	stageMax = statePtr->bufSize;
-	stageLen = stageMax;
+    while (srcLen + saved + endEncoding > 0) {
+	ChannelBuffer *bufPtr;
+	char *dst, safe[BUFFER_PADDING];
+	int result, srcRead, dstLen, dstWrote, srcLimit = srcLen;
 
-	toWrite = stageLen;
-	if (toWrite > srcLen) {
-	    toWrite = srcLen;
+	if (nextNewLine) {
+	    srcLimit = nextNewLine - src;
 	}
-
-	if (translate) {
-	    if (savedLF) {
-		/*
-		 * A '\n' was left over from last call to TranslateOutputEOL()
-		 * and we need to store it in the staging buffer. If the
-		 * channel is line-based, we will need to flush the output
-		 * buffer (after translating the staging buffer).
-		 */
-
-		*stage++ = '\n';
-		stageLen--;
-		sawLF++;
-	    }
-	    if (TranslateOutputEOL(statePtr, stage, src, &stageLen,
-		    &toWrite)) {
-		sawLF++;
-	    }
-
-	    stage -= savedLF;
-	    stageLen += savedLF;
-	    savedLF = 0;
-
-	    if (stageLen > stageMax) {
-		savedLF = 1;
-		stageLen = stageMax;
-	    }
-	} else {
-	    memcpy(stage, src, toWrite);
-	    stageLen = toWrite;
+	
+	/* Get space to write into */
+	bufPtr = statePtr->curOutPtr;
+	if (bufPtr == NULL) {
+	    bufPtr = AllocChannelBuffer(statePtr->bufSize);
+	    statePtr->curOutPtr = bufPtr;
 	}
-	src += toWrite;
-	srcLen -= toWrite;
-
-	/*
-	 * Loop over all UTF-8 characters in staging buffer, converting them
-	 * to external encoding, storing them in output buffer.
-	 */
-
-	while (stageLen + saved + endEncoding > 0) {
-	    bufPtr = statePtr->curOutPtr;
-	    if (bufPtr == NULL) {
-		bufPtr = AllocChannelBuffer(statePtr->bufSize);
-		statePtr->curOutPtr = bufPtr;
-	    }
-	    dst = InsertPoint(bufPtr);
-	    dstLen = SpaceLeft(bufPtr);
-
-	    if (saved != 0) {
-		/*
-		 * Here's some translated bytes left over from the last buffer
-		 * that we need to stick at the beginning of this buffer.
-		 */
-
-		memcpy(dst, safe, (size_t) saved);
-		bufPtr->nextAdded += saved;
-		dst += saved;
-		dstLen -= saved;
-		saved = 0;
-	    }
-
-	    result = Tcl_UtfToExternal(NULL, encoding, stage, stageLen,
-		    statePtr->outputEncodingFlags,
-		    &statePtr->outputEncodingState, dst,
-		    dstLen + BUFFER_PADDING, &stageRead, &dstWrote, NULL);
-
+	if (saved) {
 	    /*
-	     * Fix for SF #506297, reported by Martin Forssen
-	     * <ruric@users.sourceforge.net>.
-	     *
-	     * The encoding chosen in the script exposing the bug writes out
-	     * three intro characters when TCL_ENCODING_START is set, but does
-	     * not consume any input as TCL_ENCODING_END is cleared. As some
-	     * output was generated the enclosing loop calls UtfToExternal
-	     * again, again with START set. Three more characters in the out
-	     * and still no use of input ... To break this infinite loop we
-	     * remove TCL_ENCODING_START from the set of flags after the first
-	     * call (no condition is required, the later calls remove an unset
-	     * flag, which is a no-op). This causes the subsequent calls to
-	     * UtfToExternal to consume and convert the actual input.
+	     * Here's some translated bytes left over from the last buffer
+	     * that we need to stick at the beginning of this buffer.
 	     */
 
-	    statePtr->outputEncodingFlags &= ~TCL_ENCODING_START;
+	    memcpy(InsertPoint(bufPtr), safe, (size_t) saved);
+	    bufPtr->nextAdded += saved;
+	    saved = 0;
+	}
+	dst = InsertPoint(bufPtr);
+	dstLen = SpaceLeft(bufPtr);
+
+	result = Tcl_UtfToExternal(NULL, encoding, src, srcLimit,
+		statePtr->outputEncodingFlags,
+		&statePtr->outputEncodingState, dst,
+		dstLen + BUFFER_PADDING, &srcRead, &dstWrote, NULL);
+
+	/* See chan-io-1.[89]. Tcl Bug 506297. */
+	statePtr->outputEncodingFlags &= ~TCL_ENCODING_START;
+	
+	if ((result != TCL_OK) && (srcRead + dstWrote == 0)) {
+	    /* We're reading from invalid/incomplete UTF-8 */
+	    if (total == 0) {
+		Tcl_SetErrno(EINVAL);
+		return -1;
+	    }
+	    break;
+	}
 
-	    /*
-	     * The following code must be executed only when result is not 0.
-	     */
+	bufPtr->nextAdded += dstWrote;
+	src += srcRead;
+	srcLen -= srcRead;
+	total += dstWrote;
+	dst += dstWrote;
+	dstLen -= dstWrote;
 
-	    if ((result != 0) && (stageRead + dstWrote == 0)) {
-		/*
-		 * We have an incomplete UTF-8 character at the end of the
-		 * staging buffer. It will get moved to the beginning of the
-		 * staging buffer followed by more bytes from src.
-		 */
+	if (src == nextNewLine && dstLen > 0) {
+	    static char crln[3] = "\r\n";
+	    char *nl = NULL;
+	    int nlLen = 0;
 
-		src -= stageLen;
-		srcLen += stageLen;
-		stageLen = 0;
-		savedLF = 0;
+	    switch (statePtr->outputTranslation) {
+	    case TCL_TRANSLATE_LF:
+		nl = crln + 1;
+		nlLen = 1;
+		break;
+	    case TCL_TRANSLATE_CR:
+		nl = crln;
+		nlLen = 1;
+		break;
+	    case TCL_TRANSLATE_CRLF:
+		nl = crln;
+		nlLen = 2;
+		break;
+	    default:
+		Tcl_Panic("unknown output translation requested");
 		break;
 	    }
-	    bufPtr->nextAdded += dstWrote;
-	    if (IsBufferOverflowing(bufPtr)) {
-		/*
-		 * When translating from UTF-8 to external encoding, we
-		 * allowed the translation to produce a character that crossed
-		 * the end of the output buffer, so that we would get a
-		 * completely full buffer before flushing it. The extra bytes
-		 * will be moved to the beginning of the next buffer.
-		 */
+	
+	    result |= Tcl_UtfToExternal(NULL, encoding, nl, nlLen,
+		statePtr->outputEncodingFlags,
+		&statePtr->outputEncodingState, dst,
+		dstLen + BUFFER_PADDING, &srcRead, &dstWrote, NULL);
 
-		saved = -SpaceLeft(bufPtr);
-		memcpy(safe, dst + dstLen, (size_t) saved);
-		bufPtr->nextAdded = bufPtr->bufLength;
-	    }
-	    if (CheckFlush(chanPtr, bufPtr, sawLF) != 0) {
-		return -1;
+	    if (srcRead != nlLen) {
+		Tcl_Panic("Can This Happen?");
 	    }
 
+	    bufPtr->nextAdded += dstWrote;
+	    src++;
+	    srcLen--;
 	    total += dstWrote;
-	    stage += stageRead;
-	    stageLen -= stageRead;
-	    sawLF = 0;
-
-	    consumedSomething = 1;
+	    dst += dstWrote;
+	    dstLen -= dstWrote;
+	    nextNewLine = memchr(src, '\n', srcLen);
+	    needNlFlush = 1;
+	}
 
+	if (IsBufferOverflowing(bufPtr)) {
 	    /*
-	     * If all translated characters are written to the buffer,
-	     * endEncoding is set to 0 because the escape sequence may be
-	     * output.
+	     * When translating from UTF-8 to external encoding, we
+	     * allowed the translation to produce a character that crossed
+	     * the end of the output buffer, so that we would get a
+	     * completely full buffer before flushing it. The extra bytes
+	     * will be moved to the beginning of the next buffer.
 	     */
 
-	    if ((stageLen + saved == 0) && (result == 0)) {
-		endEncoding = 0;
-	    }
-	}
-    }
-
-    /*
-     * If nothing was written and it happened because there was no progress in
-     * the UTF conversion, we throw an error.
-     */
-
-    if (!consumedSomething && (total == 0)) {
-	Tcl_SetErrno(EINVAL);
-	return -1;
-    }
-    return total;
-}
-
-/*
- *---------------------------------------------------------------------------
- *
- * TranslateOutputEOL --
- *
- *	Helper function for WriteBytes() and WriteChars(). Converts the '\n'
- *	characters in the source buffer into the appropriate EOL form
- *	specified by the output translation mode.
- *
- *	EOL translation stops either when the source buffer is empty or the
- *	output buffer is full.
- *
- *	When converting to CRLF mode and there is only 1 byte left in the
- *	output buffer, this routine stores the '\r' in the last byte and then
- *	stores the '\n' in the byte just past the end of the buffer. The
- *	caller is responsible for passing in a buffer that is large enough to
- *	hold the extra byte.
- *
- * Results:
- *	The return value is 1 if a '\n' was translated from the source buffer,
- *	or 0 otherwise -- this can be used by the caller to decide to flush a
- *	line-based channel even though the channel buffer is not full.
- *
- *	*dstLenPtr is filled with how many bytes of the output buffer were
- *	used. As mentioned above, this can be one more that the output
- *	buffer's specified length if a CRLF was stored.
- *
- *	*srcLenPtr is filled with how many bytes of the source buffer were
- *	consumed.
- *
- * Side effects:
- *	It may be obvious, but bears mentioning that when converting in CRLF
- *	mode (which requires two bytes of storage in the output buffer), the
- *	number of bytes consumed from the source buffer will be less than the
- *	number of bytes stored in the output buffer.
- *
- *---------------------------------------------------------------------------
- */
-
-static int
-TranslateOutputEOL(
-    ChannelState *statePtr,	/* Channel being read, for translation and
-				 * buffering modes. */
-    char *dst,			/* Output buffer filled with UTF-8 chars by
-				 * applying appropriate EOL translation to
-				 * source characters. */
-    const char *src,		/* Source UTF-8 characters. */
-    int *dstLenPtr,		/* On entry, the maximum length of output
-				 * buffer in bytes. On exit, the number of
-				 * bytes actually used in output buffer. */
-    int *srcLenPtr)		/* On entry, the length of source buffer. On
-				 * exit, the number of bytes read from the
-				 * source buffer. */
-{
-    char *dstEnd;
-    int srcLen, newlineFound;
-
-    newlineFound = 0;
-    srcLen = *srcLenPtr;
-
-    switch (statePtr->outputTranslation) {
-    case TCL_TRANSLATE_LF:
-	for (dstEnd = dst + srcLen; dst < dstEnd; ) {
-	    if (*src == '\n') {
-		newlineFound = 1;
-	    }
-	    *dst++ = *src++;
+	    saved = -SpaceLeft(bufPtr);
+	    memcpy(safe, dst + dstLen, (size_t) saved);
+	    bufPtr->nextAdded = bufPtr->bufLength;
 	}
-	*dstLenPtr = srcLen;
-	break;
-    case TCL_TRANSLATE_CR:
-	for (dstEnd = dst + srcLen; dst < dstEnd;) {
-	    if (*src == '\n') {
-		*dst++ = '\r';
-		newlineFound = 1;
-		src++;
-	    } else {
-		*dst++ = *src++;
-	    }
-	}
-	*dstLenPtr = srcLen;
-	break;
-    case TCL_TRANSLATE_CRLF: {
-	/*
-	 * Since this causes the number of bytes to grow, we start off trying
-	 * to put 'srcLen' bytes into the output buffer, but allow it to store
-	 * more bytes, as long as there's still source bytes and room in the
-	 * output buffer.
-	 */
-
-	char *dstStart, *dstMax;
-	const char *srcStart;
-
-	dstStart = dst;
-	dstMax = dst + *dstLenPtr;
 
-	srcStart = src;
-
-	if (srcLen < *dstLenPtr) {
-	    dstEnd = dst + srcLen;
-	} else {
-	    dstEnd = dst + *dstLenPtr;
-	}
-	while (dst < dstEnd) {
-	    if (*src == '\n') {
-		if (dstEnd < dstMax) {
-		    dstEnd++;
-		}
-		*dst++ = '\r';
-		newlineFound = 1;
-	    }
-	    *dst++ = *src++;
+	if ((srcLen + saved == 0) && (result == TCL_OK)) {
+	    endEncoding = 0;
 	}
-	*srcLenPtr = src - srcStart;
-	*dstLenPtr = dst - dstStart;
-	break;
-    }
-    default:
-	break;
-    }
-    return newlineFound;
-}
-
-/*
- *---------------------------------------------------------------------------
- *
- * CheckFlush --
- *
- *	Helper function for WriteBytes() and WriteChars(). If the channel
- *	buffer is ready to be flushed, flush it.
- *
- * Results:
- *	The return value is -1 if there was a problem flushing the channel
- *	buffer, or 0 otherwise.
- *
- * Side effects:
- *	The buffer will be recycled if it is flushed.
- *
- *---------------------------------------------------------------------------
- */
-
-static int
-CheckFlush(
-    Channel *chanPtr,		/* Channel being read, for buffering mode. */
-    ChannelBuffer *bufPtr,	/* Channel buffer to possibly flush. */
-    int newlineFlag)		/* Non-zero if a the channel buffer contains a
-				 * newline. */
-{
-    ChannelState *statePtr = chanPtr->state;
-				/* State info for channel */
-
-    /*
-     * The current buffer is ready for output:
-     * 1. if it is full.
-     * 2. if it contains a newline and this channel is line-buffered.
-     * 3. if it contains any output and this channel is unbuffered.
-     */
 
-    if (!GotFlag(statePtr, BUFFER_READY)) {
 	if (IsBufferFull(bufPtr)) {
-	    SetFlag(statePtr, BUFFER_READY);
-	} else if (GotFlag(statePtr, CHANNEL_LINEBUFFERED)) {
-	    if (newlineFlag != 0) {
-		SetFlag(statePtr, BUFFER_READY);
+	    if (FlushChannel(NULL, chanPtr, 0) != 0) {
+		return -1;
+	    }
+	    flushed += statePtr->bufSize;
+	    if (saved == 0 || src[-1] != '\n') {
+		needNlFlush = 0;
 	    }
-	} else if (GotFlag(statePtr, CHANNEL_UNBUFFERED)) {
-	    SetFlag(statePtr, BUFFER_READY);
 	}
     }
-    if (GotFlag(statePtr, BUFFER_READY)) {
+    if ((flushed < total) && (GotFlag(statePtr, CHANNEL_UNBUFFERED) ||
+	    (needNlFlush && GotFlag(statePtr, CHANNEL_LINEBUFFERED)))) {
+	SetFlag(statePtr, BUFFER_READY);
 	if (FlushChannel(NULL, chanPtr, 0) != 0) {
 	    return -1;
 	}
     }
-    return 0;
+
+    return total;
 }
 
 /*
@@ -4656,16 +4284,7 @@ Tcl_GetsObj(
      */
 
     if (encoding == NULL) {
-	ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
-
-	if (tsdPtr->binaryEncoding == NULL) {
-	    tsdPtr->binaryEncoding = Tcl_GetEncoding(NULL, "iso8859-1");
-	    Tcl_CreateThreadExitHandler(FreeBinaryEncoding, NULL);
-	}
-	encoding = tsdPtr->binaryEncoding;
-	if (encoding == NULL) {
-	    Tcl_Panic("attempted gets on binary channel where no iso8859-1 encoding available");
-	}
+	encoding = GetBinaryEncoding();
     }
 
     /*
@@ -5231,6 +4850,21 @@ FreeBinaryEncoding(
 	tsdPtr->binaryEncoding = NULL;
     }
 }
+
+static Tcl_Encoding
+GetBinaryEncoding()
+{
+    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
+
+    if (tsdPtr->binaryEncoding == NULL) {
+	tsdPtr->binaryEncoding = Tcl_GetEncoding(NULL, "iso8859-1");
+	Tcl_CreateThreadExitHandler(FreeBinaryEncoding, NULL);
+    }
+    if (tsdPtr->binaryEncoding == NULL) {
+	Tcl_Panic("binary encoding is not available");
+    }
+    return tsdPtr->binaryEncoding;
+}
 
 /*
  *---------------------------------------------------------------------------
@@ -7594,14 +7228,6 @@ Tcl_SetChannelBufferSize(
 
     statePtr = ((Channel *) chan)->state;
     statePtr->bufSize = sz;
-
-    if (statePtr->outputStage != NULL) {
-	ckfree(statePtr->outputStage);
-	statePtr->outputStage = NULL;
-    }
-    if ((statePtr->encoding != NULL) && GotFlag(statePtr, TCL_WRITABLE)) {
-	statePtr->outputStage = ckalloc(statePtr->bufSize + 2);
-    }
 }
 
 /*
@@ -8242,17 +7868,6 @@ Tcl_SetChannelOption(
 	statePtr->inQueueTail = NULL;
     }
 
-    /*
-     * If encoding or bufsize changes, need to update output staging buffer.
-     */
-
-    if (statePtr->outputStage != NULL) {
-	ckfree(statePtr->outputStage);
-	statePtr->outputStage = NULL;
-    }
-    if ((statePtr->encoding != NULL) && GotFlag(statePtr, TCL_WRITABLE)) {
-	statePtr->outputStage = ckalloc(statePtr->bufSize + 2);
-    }
     return TCL_OK;
 }
 
@@ -9399,9 +9014,9 @@ CopyData(
 	}
 
 	if (outBinary || sameEncoding) {
-	    sizeb = DoWrite(outStatePtr->topChanPtr, buffer, sizeb);
+	    sizeb = WriteBytes(outStatePtr->topChanPtr, buffer, sizeb);
 	} else {
-	    sizeb = DoWriteChars(outStatePtr->topChanPtr, buffer, sizeb);
+	    sizeb = WriteChars(outStatePtr->topChanPtr, buffer, sizeb);
 	}
 
 	/*
@@ -9953,162 +9568,6 @@ CopyBuffer(
 /*
  *----------------------------------------------------------------------
  *
- * DoWrite --
- *
- *	Puts a sequence of characters into an output buffer, may queue the
- *	buffer for output if it gets full, and also remembers whether the
- *	current buffer is ready e.g. if it contains a newline and we are in
- *	line buffering mode.
- *
- * Results:
- *	The number of bytes written or -1 in case of error. If -1,
- *	Tcl_GetErrno will return the error code.
- *
- * Side effects:
- *	May buffer up output and may cause output to be produced on the
- *	channel.
- *
- *----------------------------------------------------------------------
- */
-
-static int
-DoWrite(
-    Channel *chanPtr,		/* The channel to buffer output for. */
-    const char *src,		/* Data to write. */
-    int srcLen)			/* Number of bytes to write. */
-{
-    ChannelState *statePtr = chanPtr->state;
-				/* State info for channel */
-    ChannelBuffer *outBufPtr;	/* Current output buffer. */
-    int foundNewline;		/* Did we find a newline in output? */
-    char *dPtr;
-    const char *sPtr;		/* Search variables for newline. */
-    int crsent;			/* In CRLF eol translation mode, remember the
-				 * fact that a CR was output to the channel
-				 * without its following NL. */
-    int i;			/* Loop index for newline search. */
-    int destCopied;		/* How many bytes were used in this
-				 * destination buffer to hold the output? */
-    int totalDestCopied;	/* How many bytes total were copied to the
-				 * channel buffer? */
-    int srcCopied;		/* How many bytes were copied from the source
-				 * string? */
-    char *destPtr;		/* Where in line to copy to? */
-
-    /*
-     * If we are in network (or windows) translation mode, record the fact
-     * that we have not yet sent a CR to the channel.
-     */
-
-    crsent = 0;
-
-    /*
-     * Loop filling buffers and flushing them until all output has been
-     * consumed.
-     */
-
-    srcCopied = 0;
-    totalDestCopied = 0;
-
-    while (srcLen > 0) {
-	/*
-	 * Make sure there is a current output buffer to accept output.
-	 */
-
-	if (statePtr->curOutPtr == NULL) {
-	    statePtr->curOutPtr = AllocChannelBuffer(statePtr->bufSize);
-	}
-
-	outBufPtr = statePtr->curOutPtr;
-
-	destCopied = SpaceLeft(outBufPtr);
-	if (destCopied > srcLen) {
-	    destCopied = srcLen;
-	}
-
-	destPtr = InsertPoint(outBufPtr);
-	switch (statePtr->outputTranslation) {
-	case TCL_TRANSLATE_LF:
-	    srcCopied = destCopied;
-	    memcpy(destPtr, src, (size_t) destCopied);
-	    break;
-	case TCL_TRANSLATE_CR:
-	    srcCopied = destCopied;
-	    memcpy(destPtr, src, (size_t) destCopied);
-	    for (dPtr = destPtr; dPtr < destPtr + destCopied; dPtr++) {
-		if (*dPtr == '\n') {
-		    *dPtr = '\r';
-		}
-	    }
-	    break;
-	case TCL_TRANSLATE_CRLF:
-	    for (srcCopied = 0, dPtr = destPtr, sPtr = src;
-		    dPtr < destPtr + destCopied;
-		    dPtr++, sPtr++, srcCopied++) {
-		if (*sPtr == '\n') {
-		    if (crsent) {
-			*dPtr = '\n';
-			crsent = 0;
-		    } else {
-			*dPtr = '\r';
-			crsent = 1;
-			sPtr--, srcCopied--;
-		    }
-		} else {
-		    *dPtr = *sPtr;
-		}
-	    }
-	    break;
-	case TCL_TRANSLATE_AUTO:
-	    Tcl_Panic("Tcl_Write: AUTO output translation mode not supported");
-	default:
-	    Tcl_Panic("Tcl_Write: unknown output translation mode");
-	}
-
-	/*
-	 * The current buffer is ready for output if it is full, or if it
-	 * contains a newline and this channel is line-buffered, or if it
-	 * contains any output and this channel is unbuffered.
-	 */
-
-	outBufPtr->nextAdded += destCopied;
-	if (!GotFlag(statePtr, BUFFER_READY)) {
-	    if (IsBufferFull(outBufPtr)) {
-		SetFlag(statePtr, BUFFER_READY);
-	    } else if (GotFlag(statePtr, CHANNEL_LINEBUFFERED)) {
-		for (sPtr = src, i = 0, foundNewline = 0;
-			(i < srcCopied) && (!foundNewline);
-			i++, sPtr++) {
-		    if (*sPtr == '\n') {
-			foundNewline = 1;
-			break;
-		    }
-		}
-		if (foundNewline) {
-		    SetFlag(statePtr, BUFFER_READY);
-		}
-	    } else if (GotFlag(statePtr, CHANNEL_UNBUFFERED)) {
-		SetFlag(statePtr, BUFFER_READY);
-	    }
-	}
-
-	totalDestCopied += srcCopied;
-	src += srcCopied;
-	srcLen -= srcCopied;
-
-	if (GotFlag(statePtr, BUFFER_READY)) {
-	    if (FlushChannel(NULL, chanPtr, 0) != 0) {
-		return -1;
-	    }
-	}
-    } /* Closes "while" */
-
-    return totalDestCopied;
-}
-
-/*
- *----------------------------------------------------------------------
- *
  * CopyEventProc --
  *
  *	This routine is invoked as a channel event handler for the background
@@ -11331,12 +10790,11 @@ DupChannelIntRep(
 				 * currently have an internal rep.*/
 {
     ChannelState *statePtr  = GET_CHANNELSTATE(srcPtr);
-    Interp *interpPtr = GET_CHANNELINTERP(srcPtr);
 
     SET_CHANNELSTATE(copyPtr, statePtr);
-    SET_CHANNELINTERP(copyPtr, interpPtr);
+    SET_CHANNELINTERP(copyPtr, GET_CHANNELINTERP(srcPtr));
     Tcl_Preserve(statePtr);
-    copyPtr->typePtr = &tclChannelType;
+    copyPtr->typePtr = srcPtr->typePtr;
 }
 
 /*
@@ -11362,43 +10820,29 @@ SetChannelFromAny(
     register Tcl_Obj *objPtr)	/* The object to convert. */
 {
     ChannelState *statePtr;
-    Interp *interpPtr;
 
     if (interp == NULL) {
 	return TCL_ERROR;
     }
-    if (objPtr->typePtr == &tclChannelType) {
+    if (objPtr->typePtr == &chanObjType) {
 	/*
 	 * The channel is valid until any call to DetachChannel occurs.
 	 * Ensure consistency checks are done.
 	 */
 
 	statePtr = GET_CHANNELSTATE(objPtr);
-	interpPtr = GET_CHANNELINTERP(objPtr);
 	if (GotFlag(statePtr, CHANNEL_TAINTED|CHANNEL_CLOSED)) {
 	    ResetFlag(statePtr, CHANNEL_TAINTED);
 	    Tcl_Release(statePtr);
-	    UpdateStringOfChannel(objPtr);
 	    objPtr->typePtr = NULL;
-	} else if (interpPtr != (Interp*) interp) {
+	} else if (interp != GET_CHANNELINTERP(objPtr)) {
 	    Tcl_Release(statePtr);
-	    UpdateStringOfChannel(objPtr);
 	    objPtr->typePtr = NULL;
 	}
     }
-    if (objPtr->typePtr != &tclChannelType) {
-	Tcl_Channel chan;
-
-	/*
-	 * We need a valid string with which to check for a valid channel, but
-	 * make sure not to free internal rep until validated. [Bug 1847044]
-	 */
+    if (objPtr->typePtr != &chanObjType) {
+	Tcl_Channel chan = Tcl_GetChannel(interp, TclGetString(objPtr), NULL);
 
-	if ((objPtr->typePtr != NULL) && (objPtr->bytes == NULL)) {
-	    objPtr->typePtr->updateStringProc(objPtr);
-	}
-
-	chan = Tcl_GetChannel(interp, objPtr->bytes, NULL);
 	if (chan == NULL) {
 	    return TCL_ERROR;
 	}
@@ -11408,7 +10852,7 @@ SetChannelFromAny(
 	Tcl_Preserve(statePtr);
 	SET_CHANNELSTATE(objPtr, statePtr);
 	SET_CHANNELINTERP(objPtr, interp);
-	objPtr->typePtr = &tclChannelType;
+	objPtr->typePtr = &chanObjType;
     }
     return TCL_OK;
 }
@@ -11416,45 +10860,6 @@ SetChannelFromAny(
 /*
  *----------------------------------------------------------------------
  *
- * UpdateStringOfChannel --
- *
- *	Update the string representation for an object whose internal
- *	representation is "Channel".
- *
- * Results:
- *	None.
- *
- * Side effects:
- *	The object's string may be set by converting its Unicode represention
- *	to UTF format.
- *
- *----------------------------------------------------------------------
- */
-
-static void
-UpdateStringOfChannel(
-    Tcl_Obj *objPtr)		/* Object with string rep to update. */
-{
-    if (objPtr->bytes == NULL) {
-	ChannelState *statePtr = GET_CHANNELSTATE(objPtr);
-	const char *name = statePtr->channelName;
-
-	if (name) {
-	    size_t len = strlen(name);
-
-	    objPtr->bytes = ckalloc(len + 1);
-	    objPtr->length = len;
-	    memcpy(objPtr->bytes, name, len);
-	} else {
-	    objPtr->bytes = tclEmptyStringRep;
-	    objPtr->length = 0;
-	}
-    }
-}
-
-/*
- *----------------------------------------------------------------------
- *
  * FreeChannelIntRep --
  *
  *	Release statePtr storage.
diff --git a/generic/tclIOUtil.c b/generic/tclIOUtil.c
index 6259216..f624cb7 100644
--- a/generic/tclIOUtil.c
+++ b/generic/tclIOUtil.c
@@ -19,7 +19,7 @@
  */
 
 #include "tclInt.h"
-#ifdef __WIN32__
+#ifdef _WIN32
 #   include "tclWinInt.h"
 #endif
 #include "tclFileSystem.h"
@@ -792,7 +792,7 @@ TclFinalizeFilesystem(void)
      * filesystem is likely to fail.
      */
 
-#ifdef __WIN32__
+#ifdef _WIN32
     TclWinEncodingsCleanup();
 #endif
 }
@@ -819,7 +819,7 @@ TclResetFilesystem(void)
     filesystemList = &nativeFilesystemRecord;
     theFilesystemEpoch++;
 
-#ifdef __WIN32__
+#ifdef _WIN32
     /*
      * Cleans up the win32 API filesystem proc lookup table. This must happen
      * very late in finalization so that deleting of copied dlls can occur.
@@ -3255,7 +3255,7 @@ Tcl_LoadFile(
 	return TCL_ERROR;
     }
 
-#ifndef __WIN32__
+#ifndef _WIN32
     /*
      * Do we need to set appropriate permissions on the file? This may be
      * required on some systems. On Unix we could loop over the file
diff --git a/generic/tclInt.decls b/generic/tclInt.decls
index f0e907f..9f7b106 100644
--- a/generic/tclInt.decls
+++ b/generic/tclInt.decls
@@ -1006,6 +1006,12 @@ declare 249 {
 declare 250 {
     void TclSetSlaveCancelFlags(Tcl_Interp *interp, int flags, int force)
 }
+
+# Allow extensions for optimization
+declare 251 {
+    int TclRegisterLiteral(void *envPtr,
+	    char *bytes, int length, int flags)
+}
 
 ##############################################################################
 
diff --git a/generic/tclInt.h b/generic/tclInt.h
index 5c8dbfd..2aa1725 100644
--- a/generic/tclInt.h
+++ b/generic/tclInt.h
@@ -1686,6 +1686,7 @@ typedef struct Command {
 #define CMD_TRACE_ACTIVE	    0x2
 #define CMD_HAS_EXEC_TRACES	    0x4
 #define CMD_COMPILES_EXPANDED	    0x8
+#define CMD_REDEF_IN_PROGRESS	    0x10
 
 /*
  *----------------------------------------------------------------
@@ -1809,7 +1810,14 @@ typedef struct Interp {
     ClientData interpInfo;	/* Information used by tclInterp.c to keep
 				 * track of master/slave interps on a
 				 * per-interp basis. */
-    Tcl_HashTable unused2;	/* No longer used (was mathFuncTable) */
+    union {
+	void (*optimizer)(void *envPtr);
+	Tcl_HashTable unused2;	/* No longer used (was mathFuncTable). The
+				 * unused space in interp was repurposed for
+				 * pluggable bytecode optimizers. The core
+				 * contains one optimizer, which can be
+				 * selectively overriden by extensions. */
+    } extra;
 
     /*
      * Information related to procedures and variables. See tclProc.c and
@@ -2632,6 +2640,8 @@ MODULE_SCOPE char *tclMemDumpFileName;
 MODULE_SCOPE TclPlatformType tclPlatform;
 MODULE_SCOPE Tcl_NotifierProcs tclNotifierHooks;
 
+MODULE_SCOPE Tcl_Encoding tclIdentityEncoding;
+
 /*
  * TIP #233 (Virtualized Time)
  * Data for the time hooks, if any.
@@ -3435,6 +3445,9 @@ MODULE_SCOPE int	TclCompileBreakCmd(Tcl_Interp *interp,
 MODULE_SCOPE int	TclCompileCatchCmd(Tcl_Interp *interp,
 			    Tcl_Parse *parsePtr, Command *cmdPtr,
 			    struct CompileEnv *envPtr);
+MODULE_SCOPE int	TclCompileConcatCmd(Tcl_Interp *interp,
+			    Tcl_Parse *parsePtr, Command *cmdPtr,
+			    struct CompileEnv *envPtr);
 MODULE_SCOPE int	TclCompileContinueCmd(Tcl_Interp *interp,
 			    Tcl_Parse *parsePtr, Command *cmdPtr,
 			    struct CompileEnv *envPtr);
@@ -3534,6 +3547,9 @@ MODULE_SCOPE int	TclCompileLassignCmd(Tcl_Interp *interp,
 MODULE_SCOPE int	TclCompileLindexCmd(Tcl_Interp *interp,
 			    Tcl_Parse *parsePtr, Command *cmdPtr,
 			    struct CompileEnv *envPtr);
+MODULE_SCOPE int	TclCompileLinsertCmd(Tcl_Interp *interp,
+			    Tcl_Parse *parsePtr, Command *cmdPtr,
+			    struct CompileEnv *envPtr);
 MODULE_SCOPE int	TclCompileListCmd(Tcl_Interp *interp,
 			    Tcl_Parse *parsePtr, Command *cmdPtr,
 			    struct CompileEnv *envPtr);
@@ -3558,6 +3574,9 @@ MODULE_SCOPE int	TclCompileNamespaceCodeCmd(Tcl_Interp *interp,
 MODULE_SCOPE int	TclCompileNamespaceCurrentCmd(Tcl_Interp *interp,
 			    Tcl_Parse *parsePtr, Command *cmdPtr,
 			    struct CompileEnv *envPtr);
+MODULE_SCOPE int	TclCompileNamespaceOriginCmd(Tcl_Interp *interp,
+			    Tcl_Parse *parsePtr, Command *cmdPtr,
+			    struct CompileEnv *envPtr);
 MODULE_SCOPE int	TclCompileNamespaceQualifiersCmd(Tcl_Interp *interp,
 			    Tcl_Parse *parsePtr, Command *cmdPtr,
 			    struct CompileEnv *envPtr);
@@ -3573,6 +3592,12 @@ MODULE_SCOPE int	TclCompileNamespaceWhichCmd(Tcl_Interp *interp,
 MODULE_SCOPE int	TclCompileNoOp(Tcl_Interp *interp,
 			    Tcl_Parse *parsePtr, Command *cmdPtr,
 			    struct CompileEnv *envPtr);
+MODULE_SCOPE int	TclCompileObjectNextCmd(Tcl_Interp *interp,
+			    Tcl_Parse *parsePtr, Command *cmdPtr,
+			    struct CompileEnv *envPtr);
+MODULE_SCOPE int	TclCompileObjectNextToCmd(Tcl_Interp *interp,
+			    Tcl_Parse *parsePtr, Command *cmdPtr,
+			    struct CompileEnv *envPtr);
 MODULE_SCOPE int	TclCompileObjectSelfCmd(Tcl_Interp *interp,
 			    Tcl_Parse *parsePtr, Command *cmdPtr,
 			    struct CompileEnv *envPtr);
@@ -3600,6 +3625,9 @@ MODULE_SCOPE int	TclCompileStringFirstCmd(Tcl_Interp *interp,
 MODULE_SCOPE int	TclCompileStringIndexCmd(Tcl_Interp *interp,
 			    Tcl_Parse *parsePtr, Command *cmdPtr,
 			    struct CompileEnv *envPtr);
+MODULE_SCOPE int	TclCompileStringIsCmd(Tcl_Interp *interp,
+			    Tcl_Parse *parsePtr, Command *cmdPtr,
+			    struct CompileEnv *envPtr);
 MODULE_SCOPE int	TclCompileStringLastCmd(Tcl_Interp *interp,
 			    Tcl_Parse *parsePtr, Command *cmdPtr,
 			    struct CompileEnv *envPtr);
@@ -3615,6 +3643,27 @@ MODULE_SCOPE int	TclCompileStringMatchCmd(Tcl_Interp *interp,
 MODULE_SCOPE int	TclCompileStringRangeCmd(Tcl_Interp *interp,
 			    Tcl_Parse *parsePtr, Command *cmdPtr,
 			    struct CompileEnv *envPtr);
+MODULE_SCOPE int	TclCompileStringReplaceCmd(Tcl_Interp *interp,
+			    Tcl_Parse *parsePtr, Command *cmdPtr,
+			    struct CompileEnv *envPtr);
+MODULE_SCOPE int	TclCompileStringToLowerCmd(Tcl_Interp *interp,
+			    Tcl_Parse *parsePtr, Command *cmdPtr,
+			    struct CompileEnv *envPtr);
+MODULE_SCOPE int	TclCompileStringToTitleCmd(Tcl_Interp *interp,
+			    Tcl_Parse *parsePtr, Command *cmdPtr,
+			    struct CompileEnv *envPtr);
+MODULE_SCOPE int	TclCompileStringToUpperCmd(Tcl_Interp *interp,
+			    Tcl_Parse *parsePtr, Command *cmdPtr,
+			    struct CompileEnv *envPtr);
+MODULE_SCOPE int	TclCompileStringTrimCmd(Tcl_Interp *interp,
+			    Tcl_Parse *parsePtr, Command *cmdPtr,
+			    struct CompileEnv *envPtr);
+MODULE_SCOPE int	TclCompileStringTrimLCmd(Tcl_Interp *interp,
+			    Tcl_Parse *parsePtr, Command *cmdPtr,
+			    struct CompileEnv *envPtr);
+MODULE_SCOPE int	TclCompileStringTrimRCmd(Tcl_Interp *interp,
+			    Tcl_Parse *parsePtr, Command *cmdPtr,
+			    struct CompileEnv *envPtr);
 MODULE_SCOPE int	TclCompileSubstCmd(Tcl_Interp *interp,
 			    Tcl_Parse *parsePtr, Command *cmdPtr,
 			    struct CompileEnv *envPtr);
@@ -3645,6 +3694,9 @@ MODULE_SCOPE int	TclCompileWhileCmd(Tcl_Interp *interp,
 MODULE_SCOPE int	TclCompileYieldCmd(Tcl_Interp *interp,
 			    Tcl_Parse *parsePtr, Command *cmdPtr,
 			    struct CompileEnv *envPtr);
+MODULE_SCOPE int	TclCompileYieldToCmd(Tcl_Interp *interp,
+			    Tcl_Parse *parsePtr, Command *cmdPtr,
+			    struct CompileEnv *envPtr);
 MODULE_SCOPE int	TclCompileBasic0ArgCmd(Tcl_Interp *interp,
 			    Tcl_Parse *parsePtr, Command *cmdPtr,
 			    struct CompileEnv *envPtr);
diff --git a/generic/tclIntDecls.h b/generic/tclIntDecls.h
index 47c6afd..f95f999 100644
--- a/generic/tclIntDecls.h
+++ b/generic/tclIntDecls.h
@@ -614,6 +614,9 @@ EXTERN char *		TclDoubleDigits(double dv, int ndigits, int flags,
 /* 250 */
 EXTERN void		TclSetSlaveCancelFlags(Tcl_Interp *interp, int flags,
 				int force);
+/* 251 */
+EXTERN int		TclRegisterLiteral(void *envPtr, char *bytes,
+				int length, int flags);
 
 typedef struct TclIntStubs {
     int magic;
@@ -870,6 +873,7 @@ typedef struct TclIntStubs {
     int (*tclCopyChannel) (Tcl_Interp *interp, Tcl_Channel inChan, Tcl_Channel outChan, Tcl_WideInt toRead, Tcl_Obj *cmdPtr); /* 248 */
     char * (*tclDoubleDigits) (double dv, int ndigits, int flags, int *decpt, int *signum, char **endPtr); /* 249 */
     void (*tclSetSlaveCancelFlags) (Tcl_Interp *interp, int flags, int force); /* 250 */
+    int (*tclRegisterLiteral) (void *envPtr, char *bytes, int length, int flags); /* 251 */
 } TclIntStubs;
 
 extern const TclIntStubs *tclIntStubsPtr;
@@ -1299,6 +1303,8 @@ extern const TclIntStubs *tclIntStubsPtr;
 	(tclIntStubsPtr->tclDoubleDigits) /* 249 */
 #define TclSetSlaveCancelFlags \
 	(tclIntStubsPtr->tclSetSlaveCancelFlags) /* 250 */
+#define TclRegisterLiteral \
+	(tclIntStubsPtr->tclRegisterLiteral) /* 251 */
 
 #endif /* defined(USE_TCL_STUBS) */
 
diff --git a/generic/tclIntPlatDecls.h b/generic/tclIntPlatDecls.h
index 72719fe..2c74b5a 100644
--- a/generic/tclIntPlatDecls.h
+++ b/generic/tclIntPlatDecls.h
@@ -13,7 +13,7 @@
 #ifndef _TCLINTPLATDECLS
 #define _TCLINTPLATDECLS
 
-#ifdef __WIN32__
+#ifdef _WIN32
 #   define Tcl_DirEntry void
 #   define DIR void
 #endif
@@ -45,7 +45,7 @@ extern "C" {
  * Exported function declarations:
  */
 
-#if !defined(__WIN32__) && !defined(__CYGWIN__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(__CYGWIN__) && !defined(MAC_OSX_TCL) /* UNIX */
 /* 0 */
 EXTERN void		TclGetAndDetachPids(Tcl_Interp *interp,
 				Tcl_Channel chan);
@@ -104,7 +104,7 @@ EXTERN int		TclUnixOpenTemporaryFile(Tcl_Obj *dirObj,
 				Tcl_Obj *basenameObj, Tcl_Obj *extensionObj,
 				Tcl_Obj *resultingNameObj);
 #endif /* UNIX */
-#if defined(__WIN32__) || defined(__CYGWIN__) /* WIN */
+#if defined(_WIN32) || defined(__CYGWIN__) /* WIN */
 /* 0 */
 EXTERN void		TclWinConvertError(DWORD errCode);
 /* 1 */
@@ -258,7 +258,7 @@ typedef struct TclIntPlatStubs {
     int magic;
     void *hooks;
 
-#if !defined(__WIN32__) && !defined(__CYGWIN__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(__CYGWIN__) && !defined(MAC_OSX_TCL) /* UNIX */
     void (*tclGetAndDetachPids) (Tcl_Interp *interp, Tcl_Channel chan); /* 0 */
     int (*tclpCloseFile) (TclFile file); /* 1 */
     Tcl_Channel (*tclpCreateCommandChannel) (TclFile readFile, TclFile writeFile, TclFile errorFile, int numPids, Tcl_Pid *pidPtr); /* 2 */
@@ -291,7 +291,7 @@ typedef struct TclIntPlatStubs {
     int (*tclWinCPUID) (unsigned int index, unsigned int *regs); /* 29 */
     int (*tclUnixOpenTemporaryFile) (Tcl_Obj *dirObj, Tcl_Obj *basenameObj, Tcl_Obj *extensionObj, Tcl_Obj *resultingNameObj); /* 30 */
 #endif /* UNIX */
-#if defined(__WIN32__) || defined(__CYGWIN__) /* WIN */
+#if defined(_WIN32) || defined(__CYGWIN__) /* WIN */
     void (*tclWinConvertError) (DWORD errCode); /* 0 */
     void (*tclWinConvertWSAError) (DWORD errCode); /* 1 */
     struct servent * (*tclWinGetServByName) (const char *nm, const char *proto); /* 2 */
@@ -371,7 +371,7 @@ extern const TclIntPlatStubs *tclIntPlatStubsPtr;
  * Inline function declarations:
  */
 
-#if !defined(__WIN32__) && !defined(__CYGWIN__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(__CYGWIN__) && !defined(MAC_OSX_TCL) /* UNIX */
 #define TclGetAndDetachPids \
 	(tclIntPlatStubsPtr->tclGetAndDetachPids) /* 0 */
 #define TclpCloseFile \
@@ -420,7 +420,7 @@ extern const TclIntPlatStubs *tclIntPlatStubsPtr;
 #define TclUnixOpenTemporaryFile \
 	(tclIntPlatStubsPtr->tclUnixOpenTemporaryFile) /* 30 */
 #endif /* UNIX */
-#if defined(__WIN32__) || defined(__CYGWIN__) /* WIN */
+#if defined(_WIN32) || defined(__CYGWIN__) /* WIN */
 #define TclWinConvertError \
 	(tclIntPlatStubsPtr->tclWinConvertError) /* 0 */
 #define TclWinConvertWSAError \
@@ -550,7 +550,7 @@ extern const TclIntPlatStubs *tclIntPlatStubsPtr;
 #undef TclpInetNtoa
 #define TclpInetNtoa inet_ntoa
 
-#if defined(__WIN32__) || defined(__CYGWIN__)
+#if defined(_WIN32) || defined(__CYGWIN__)
 #   undef TclWinNToHS
 #   define TclWinNToHS ntohs
 #else
diff --git a/generic/tclLiteral.c b/generic/tclLiteral.c
index 11da6f8..2b0cc7e 100644
--- a/generic/tclLiteral.c
+++ b/generic/tclLiteral.c
@@ -358,7 +358,7 @@ TclFetchLiteral(
 
 int
 TclRegisterLiteral(
-    CompileEnv *envPtr,		/* Points to the CompileEnv in whose object
+    void *ePtr,		/* Points to the CompileEnv in whose object
 				 * array an object is found or created. */
     register char *bytes,	/* Points to string for which to find or
 				 * create an object in CompileEnv's object
@@ -372,6 +372,7 @@ TclRegisterLiteral(
 				 * the literal should not be shared accross
 				 * namespaces. */
 {
+    CompileEnv *envPtr = ePtr;
     Interp *iPtr = envPtr->iPtr;
     LiteralTable *localTablePtr = &envPtr->localLitTable;
     LiteralEntry *globalPtr, *localPtr;
diff --git a/generic/tclLoad.c b/generic/tclLoad.c
index 5cacab1..7c70e03 100644
--- a/generic/tclLoad.c
+++ b/generic/tclLoad.c
@@ -830,7 +830,7 @@ Tcl_UnloadObjCmd(
 	 * Unload the shared library from the application memory...
 	 */
 
-#if defined(TCL_UNLOAD_DLLS) || defined(__WIN32__)
+#if defined(TCL_UNLOAD_DLLS) || defined(_WIN32)
 	/*
 	 * Some Unix dlls are poorly behaved - registering things like atexit
 	 * calls that can't be unregistered. If you unload such dlls, you get
@@ -1151,7 +1151,7 @@ TclFinalizeLoad(void)
 	pkgPtr = firstPackagePtr;
 	firstPackagePtr = pkgPtr->nextPtr;
 
-#if defined(TCL_UNLOAD_DLLS) || defined(__WIN32__)
+#if defined(TCL_UNLOAD_DLLS) || defined(_WIN32)
 	/*
 	 * Some Unix dlls are poorly behaved - registering things like atexit
 	 * calls that can't be unregistered. If you unload such dlls, you get
diff --git a/generic/tclMain.c b/generic/tclMain.c
index faea75a..360f5e9 100644
--- a/generic/tclMain.c
+++ b/generic/tclMain.c
@@ -47,7 +47,7 @@
  * we have to translate that to strcmp here.
  */
 
-#ifndef __WIN32__
+#ifndef _WIN32
 #   define TCHAR char
 #   define TEXT(arg) arg
 #   define _tcscmp strcmp
diff --git a/generic/tclNamesp.c b/generic/tclNamesp.c
index cd44455..8f2f10e 100644
--- a/generic/tclNamesp.c
+++ b/generic/tclNamesp.c
@@ -171,7 +171,7 @@ static const EnsembleImplMap defaultNamespaceMap[] = {
     {"forget",	   NamespaceForgetCmd,	TclCompileBasicMin0ArgCmd, NULL, NULL, 0},
     {"import",	   NamespaceImportCmd,	TclCompileBasicMin0ArgCmd, NULL, NULL, 0},
     {"inscope",	   NamespaceInscopeCmd,	NULL, NRNamespaceInscopeCmd, NULL, 0},
-    {"origin",	   NamespaceOriginCmd,	TclCompileBasic1ArgCmd, NULL, NULL, 0},
+    {"origin",	   NamespaceOriginCmd,	TclCompileNamespaceOriginCmd, NULL, NULL, 0},
     {"parent",	   NamespaceParentCmd,	TclCompileBasic0Or1ArgCmd, NULL, NULL, 0},
     {"path",	   NamespacePathCmd,	TclCompileBasic0Or1ArgCmd, NULL, NULL, 0},
     {"qualifiers", NamespaceQualifiersCmd, TclCompileNamespaceQualifiersCmd, NULL, NULL, 0},
diff --git a/generic/tclOO.c b/generic/tclOO.c
index 529640f..de00733 100644
--- a/generic/tclOO.c
+++ b/generic/tclOO.c
@@ -437,10 +437,12 @@ InitFoundation(
      * ensemble.
      */
 
-    Tcl_CreateObjCommand(interp, "::oo::Helpers::next", TclOONextObjCmd, NULL,
-	    NULL);
-    Tcl_CreateObjCommand(interp, "::oo::Helpers::nextto", TclOONextToObjCmd,
-	    NULL, NULL);
+    cmdPtr = (Command *) Tcl_NRCreateCommand(interp, "::oo::Helpers::next",
+	    NULL, TclOONextObjCmd, NULL, NULL);
+    cmdPtr->compileProc = TclCompileObjectNextCmd;
+    cmdPtr = (Command *) Tcl_NRCreateCommand(interp, "::oo::Helpers::nextto",
+	    NULL, TclOONextToObjCmd, NULL, NULL);
+    cmdPtr->compileProc = TclCompileObjectNextToCmd;
     cmdPtr = (Command *) Tcl_CreateObjCommand(interp, "::oo::Helpers::self",
 	    TclOOSelfObjCmd, NULL, NULL);
     cmdPtr->compileProc = TclCompileObjectSelfCmd;
diff --git a/generic/tclOOBasic.c b/generic/tclOOBasic.c
index 853e2ec..0b0516b 100644
--- a/generic/tclOOBasic.c
+++ b/generic/tclOOBasic.c
@@ -17,16 +17,11 @@
 #include "tclOOInt.h"
 
 static inline Tcl_Object *AddConstructionFinalizer(Tcl_Interp *interp);
-static int		AfterNRDestructor(ClientData data[],
-			    Tcl_Interp *interp, int result);
-static int		DecrRefsPostClassConstructor(ClientData data[],
-			    Tcl_Interp *interp, int result);
-static int		FinalizeConstruction(ClientData data[],
-			    Tcl_Interp *interp, int result);
-static int		FinalizeEval(ClientData data[],
-			    Tcl_Interp *interp, int result);
-static int		RestoreFrame(ClientData data[],
-			    Tcl_Interp *interp, int result);
+static Tcl_NRPostProc	AfterNRDestructor;
+static Tcl_NRPostProc	DecrRefsPostClassConstructor;
+static Tcl_NRPostProc	FinalizeConstruction;
+static Tcl_NRPostProc	FinalizeEval;
+static Tcl_NRPostProc	NextRestoreFrame;
 
 /*
  * ----------------------------------------------------------------------
@@ -808,7 +803,7 @@ TclOONextObjCmd(
      * that this is like [uplevel 1] and not [eval].
      */
 
-    TclNRAddCallback(interp, RestoreFrame, framePtr, NULL, NULL, NULL);
+    TclNRAddCallback(interp, NextRestoreFrame, framePtr, NULL,NULL,NULL);
     iPtr->varFramePtr = framePtr->callerVarPtr;
     return TclNRObjectContextInvokeNext(interp, context, objc, objv, 1);
 }
@@ -826,6 +821,7 @@ TclOONextToObjCmd(
     CallContext *contextPtr;
     int i;
     Tcl_Object object;
+    const char *methodType;
 
     /*
      * Start with sanity checks on the calling context to make sure that we
@@ -877,8 +873,8 @@ TclOONextToObjCmd(
 	     * context. Note that this is like [uplevel 1] and not [eval].
 	     */
 
-	    TclNRAddCallback(interp, RestoreFrame, framePtr, contextPtr,
-		    INT2PTR(contextPtr->index), NULL);
+	    TclNRAddCallback(interp, NextRestoreFrame, framePtr,
+		    contextPtr, INT2PTR(contextPtr->index), NULL);
 	    contextPtr->index = i-1;
 	    iPtr->varFramePtr = framePtr->callerVarPtr;
 	    return TclNRObjectContextInvokeNext(interp,
@@ -891,24 +887,35 @@ TclOONextToObjCmd(
      * is on the chain but unreachable, or not on the chain at all.
      */
 
+    if (contextPtr->callPtr->flags & CONSTRUCTOR) {
+	methodType = "constructor";
+    } else if (contextPtr->callPtr->flags & DESTRUCTOR) {
+	methodType = "destructor";
+    } else {
+	methodType = "method";
+    }
+
     for (i=contextPtr->index ; i>=0 ; i--) {
 	struct MInvoke *miPtr = contextPtr->callPtr->chain + i;
 
 	if (!miPtr->isFilter && miPtr->mPtr->declaringClassPtr == classPtr) {
 	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
-		    "method implementation by \"%s\" not reachable from here",
-		    TclGetString(objv[1])));
+		    "%s implementation by \"%s\" not reachable from here",
+		    methodType, TclGetString(objv[1])));
+	    Tcl_SetErrorCode(interp, "TCL", "OO", "CLASS_NOT_REACHABLE",
+		    NULL);
 	    return TCL_ERROR;
 	}
     }
     Tcl_SetObjResult(interp, Tcl_ObjPrintf(
-	    "method has no non-filter implementation by \"%s\"",
-	    TclGetString(objv[1])));
+	    "%s has no non-filter implementation by \"%s\"",
+	    methodType, TclGetString(objv[1])));
+    Tcl_SetErrorCode(interp, "TCL", "OO", "CLASS_NOT_THERE", NULL);
     return TCL_ERROR;
 }
 
 static int
-RestoreFrame(
+NextRestoreFrame(
     ClientData data[],
     Tcl_Interp *interp,
     int result)
diff --git a/generic/tclOptimize.c b/generic/tclOptimize.c
index 3b16e6e..827d89d 100644
--- a/generic/tclOptimize.c
+++ b/generic/tclOptimize.c
@@ -191,7 +191,7 @@ TrimUnreachable(
  * ConvertZeroEffectToNOP --
  *
  *	Replace PUSH/POP sequences (when non-hazardous) with NOPs. Also
- *	replace PUSH empty/CONCAT and TRY_CVT_NUMERIC (when followed by an
+ *	replace PUSH empty/STR_CONCAT and TRY_CVT_NUMERIC (when followed by an
  *	operation that guarantees the check for arithmeticity) and eliminate
  *	LNOT when we can invert the following JUMP condition.
  *
@@ -227,7 +227,7 @@ ConvertZeroEffectToNOP(
 	case INST_PUSH1:
 	    if (nextInst == INST_POP) {
 		blank = size + InstLength(nextInst);
-	    } else if (nextInst == INST_CONCAT1
+	    } else if (nextInst == INST_STR_CONCAT1
 		    && TclGetUInt1AtPtr(currentInstPtr + size + 1) == 2) {
 		Tcl_Obj *litPtr = TclFetchLiteral(envPtr,
 			TclGetUInt1AtPtr(currentInstPtr + 1));
@@ -242,7 +242,7 @@ ConvertZeroEffectToNOP(
 	case INST_PUSH4:
 	    if (nextInst == INST_POP) {
 		blank = size + 1;
-	    } else if (nextInst == INST_CONCAT1
+	    } else if (nextInst == INST_STR_CONCAT1
 		    && TclGetUInt1AtPtr(currentInstPtr + size + 1) == 2) {
 		Tcl_Obj *litPtr = TclFetchLiteral(envPtr,
 			TclGetUInt4AtPtr(currentInstPtr + 1));
@@ -427,7 +427,7 @@ AdvanceJumps(
 
 void
 TclOptimizeBytecode(
-    CompileEnv *envPtr)
+    void *envPtr)
 {
     ConvertZeroEffectToNOP(envPtr);
     AdvanceJumps(envPtr);
diff --git a/generic/tclPathObj.c b/generic/tclPathObj.c
index b7f3dcf..fe6063f 100644
--- a/generic/tclPathObj.c
+++ b/generic/tclPathObj.c
@@ -512,7 +512,7 @@ TclFSGetPathType(
 
     if (PATHFLAGS(pathPtr) == 0) {
 	/* The path is not absolute... */
-#ifdef __WIN32__
+#ifdef _WIN32
 	/* ... on Windows we must make another call to determine whether
 	 * it's relative or volumerelative [Bug 2571597]. */
 	return TclGetPathType(pathPtr, filesystemPtrPtr, driveNameLengthPtr,
@@ -1956,7 +1956,7 @@ Tcl_FSGetNormalizedPath(
 		/*
 		 * We have a refCount on the cwd.
 		 */
-#ifdef __WIN32__
+#ifdef _WIN32
 	    } else if (type == TCL_PATH_VOLUME_RELATIVE) {
 		/*
 		 * Only Windows has volume-relative paths.
@@ -1969,7 +1969,7 @@ Tcl_FSGetNormalizedPath(
 		    return NULL;
 		}
 		pureNormalized = 0;
-#endif /* __WIN32__ */
+#endif /* _WIN32 */
 	    }
 	}
 
diff --git a/generic/tclPlatDecls.h b/generic/tclPlatDecls.h
index 681854d..abc8ee8 100644
--- a/generic/tclPlatDecls.h
+++ b/generic/tclPlatDecls.h
@@ -50,7 +50,7 @@ extern "C" {
  * Exported function declarations:
  */
 
-#if defined(__WIN32__) || defined(__CYGWIN__) /* WIN */
+#if defined(_WIN32) || defined(__CYGWIN__) /* WIN */
 /* 0 */
 EXTERN TCHAR *		Tcl_WinUtfToTChar(const char *str, int len,
 				Tcl_DString *dsPtr);
@@ -75,7 +75,7 @@ typedef struct TclPlatStubs {
     int magic;
     void *hooks;
 
-#if defined(__WIN32__) || defined(__CYGWIN__) /* WIN */
+#if defined(_WIN32) || defined(__CYGWIN__) /* WIN */
     TCHAR * (*tcl_WinUtfToTChar) (const char *str, int len, Tcl_DString *dsPtr); /* 0 */
     char * (*tcl_WinTCharToUtf) (const TCHAR *str, int len, Tcl_DString *dsPtr); /* 1 */
 #endif /* WIN */
@@ -97,7 +97,7 @@ extern const TclPlatStubs *tclPlatStubsPtr;
  * Inline function declarations:
  */
 
-#if defined(__WIN32__) || defined(__CYGWIN__) /* WIN */
+#if defined(_WIN32) || defined(__CYGWIN__) /* WIN */
 #define Tcl_WinUtfToTChar \
 	(tclPlatStubsPtr->tcl_WinUtfToTChar) /* 0 */
 #define Tcl_WinTCharToUtf \
diff --git a/generic/tclProc.c b/generic/tclProc.c
index 1314719..ce1c767 100644
--- a/generic/tclProc.c
+++ b/generic/tclProc.c
@@ -1855,9 +1855,39 @@ InterpProcNR2(
     }
 
     /*
-     * Process the result code.
+     * Free the stack-allocated compiled locals and CallFrame. It is important
+     * to pop the call frame without freeing it first: the compiledLocals
+     * cannot be freed before the frame is popped, as the local variables must
+     * be deleted. But the compiledLocals must be freed first, as they were
+     * allocated later on the stack.
      */
 
+    if (result != TCL_OK) {
+	goto process;
+    }
+    
+    done: 
+    if (TCL_DTRACE_PROC_RESULT_ENABLED()) {
+	int l = iPtr->varFramePtr->isProcCallFrame & FRAME_IS_LAMBDA ? 1 : 0;
+	Tcl_Obj *r = Tcl_GetObjResult(interp);
+
+	TCL_DTRACE_PROC_RESULT(l < iPtr->varFramePtr->objc ?
+		TclGetString(iPtr->varFramePtr->objv[l]) : NULL, result,
+		TclGetString(r), r);
+    }
+
+    freePtr = iPtr->framePtr;
+    Tcl_PopCallFrame(interp);		/* Pop but do not free. */
+    TclStackFree(interp, freePtr->compiledLocals);
+					/* Free compiledLocals. */
+    TclStackFree(interp, freePtr);	/* Free CallFrame. */
+    return result;
+
+    /*
+     * Process any non-TCL_OK result code.
+     */
+
+    process:
     switch (result) {
     case TCL_RETURN:
 	/*
@@ -1892,46 +1922,8 @@ InterpProcNR2(
 	 */
 
 	errorProc(interp, procNameObj);
-
-    default:
-	/*
-	 * Process other results (OK and non-standard) by doing nothing
-	 * special, skipping directly to the code afterwards that cleans up
-	 * associated memory.
-	 *
-	 * Non-standard results are processed by passing them through quickly.
-	 * This means they all work as exceptions, unwinding the stack quickly
-	 * and neatly. Who knows how well they are handled by third-party code
-	 * though...
-	 */
-
-	(void) 0;		/* do nothing */
-    }
-
-    if (TCL_DTRACE_PROC_RESULT_ENABLED()) {
-	int l = iPtr->varFramePtr->isProcCallFrame & FRAME_IS_LAMBDA ? 1 : 0;
-	Tcl_Obj *r = Tcl_GetObjResult(interp);
-
-	TCL_DTRACE_PROC_RESULT(l < iPtr->varFramePtr->objc ?
-		TclGetString(iPtr->varFramePtr->objv[l]) : NULL, result,
-		TclGetString(r), r);
     }
-
-    /*
-     * Free the stack-allocated compiled locals and CallFrame. It is important
-     * to pop the call frame without freeing it first: the compiledLocals
-     * cannot be freed before the frame is popped, as the local variables must
-     * be deleted. But the compiledLocals must be freed first, as they were
-     * allocated later on the stack.
-     */
-
-    freePtr = iPtr->framePtr;
-    Tcl_PopCallFrame(interp);		/* Pop but do not free. */
-    TclStackFree(interp, freePtr->compiledLocals);
-					/* Free compiledLocals. */
-    TclStackFree(interp, freePtr);	/* Free CallFrame. */
-
-    return result;
+    goto done;
 }
 
 /*
diff --git a/generic/tclStringObj.c b/generic/tclStringObj.c
index e495c2e..dffa38c 100644
--- a/generic/tclStringObj.c
+++ b/generic/tclStringObj.c
@@ -1281,23 +1281,43 @@ Tcl_AppendObjToObj(
 
     if ((TclIsPureByteArray(objPtr) || objPtr->bytes == tclEmptyStringRep)
 	    && TclIsPureByteArray(appendObjPtr)) {
-	unsigned char *bytesSrc;
-	int lengthSrc, lengthTotal;
 
 	/*
-	 * We do not assume that objPtr and appendObjPtr must be distinct!
-	 * This makes this code a bit more complex than it otherwise would be,
-	 * but in turn makes it much safer.
+	 * You might expect the code here to be
+	 *
+	 *  bytes = Tcl_GetByteArrayFromObj(appendObjPtr, &length);
+	 *  TclAppendBytesToByteArray(objPtr, bytes, length);
+	 *
+	 * and essentially all of the time that would be fine.  However,
+	 * it would run into trouble in the case where objPtr and
+	 * appendObjPtr point to the same thing.  That may never be a
+	 * good idea.  It seems to violate Copy On Write, and we don't
+	 * have any tests for the situation, since making any Tcl commands
+	 * that call Tcl_AppendObjToObj() do that appears impossible
+	 * (They honor Copy On Write!).  For the sake of extensions that
+	 * go off into that realm, though, here's a more complex approach
+	 * that can handle all the cases.
 	 */
 
+	/* Get lengths */
+	int lengthSrc;
+
 	(void) Tcl_GetByteArrayFromObj(objPtr, &length);
 	(void) Tcl_GetByteArrayFromObj(appendObjPtr, &lengthSrc);
-	lengthTotal = length + lengthSrc;
-	if (((length > lengthSrc) ? length : lengthSrc) > lengthTotal) {
-	    Tcl_Panic("max size for a Tcl value (%d bytes) exceeded", INT_MAX);
-	}
-	bytesSrc = Tcl_GetByteArrayFromObj(appendObjPtr, NULL);
-	TclAppendBytesToByteArray(objPtr, bytesSrc, lengthSrc);
+
+	/* Grow buffer enough for the append */
+	TclAppendBytesToByteArray(objPtr, NULL, lengthSrc);
+
+	/* Reset objPtr back to the original value */
+	Tcl_SetByteArrayLength(objPtr, length);
+
+	/*
+	 * Now do the append knowing that buffer growth cannot cause
+	 * any trouble.
+	 */
+
+	TclAppendBytesToByteArray(objPtr,
+		Tcl_GetByteArrayFromObj(appendObjPtr, NULL), lengthSrc);
 	return;
     }
 
diff --git a/generic/tclStringTrim.h b/generic/tclStringTrim.h
new file mode 100644
index 0000000..030e4ec
--- /dev/null
+++ b/generic/tclStringTrim.h
@@ -0,0 +1,43 @@
+/*
+ * tclStringTrim.h --
+ *
+ *	This file contains the definition of what characters are to be trimmed
+ *	from a string by [string trim] by default. It's only needed by Tcl's
+ *	implementation; it does not form a public or private API at all.
+ *
+ * Copyright (c) 1987-1993 The Regents of the University of California.
+ * Copyright (c) 1994-1997 Sun Microsystems, Inc.
+ * Copyright (c) 1998-2000 Scriptics Corporation.
+ * Copyright (c) 2002 ActiveState Corporation.
+ * Copyright (c) 2003-2013 Donal K. Fellows.
+ *
+ * See the file "license.terms" for information on usage and redistribution of
+ * this file, and for a DISCLAIMER OF ALL WARRANTIES.
+ */
+
+#ifndef TCL_STRING_TRIM_H
+#define TCL_STRING_TRIM_H
+
+/*
+ * Default set of characters to trim in [string trim] and friends. This is a
+ * UTF-8 literal string containing all Unicode space characters. [TIP #413]
+ */
+
+MODULE_SCOPE const char tclDefaultTrimSet[];
+
+/*
+ * The whitespace trimming set used when [concat]enating. This is a subset of
+ * the above, and deliberately so.
+ */
+
+#define CONCAT_TRIM_SET " \f\v\r\t\n"
+
+#endif /* TCL_STRING_TRIM_H */
+
+/*
+ * Local Variables:
+ * mode: c
+ * c-basic-offset: 4
+ * fill-column: 78
+ * End:
+ */
diff --git a/generic/tclStubInit.c b/generic/tclStubInit.c
index 3f1c27b..097269f 100644
--- a/generic/tclStubInit.c
+++ b/generic/tclStubInit.c
@@ -90,7 +90,7 @@ static unsigned short TclWinNToHS(unsigned short ns) {
 }
 #endif
 
-#ifdef __WIN32__
+#ifdef _WIN32
 #   define TclUnixWaitForFile 0
 #   define TclUnixCopyFile 0
 #   define TclUnixOpenTemporaryFile 0
@@ -551,12 +551,13 @@ static const TclIntStubs tclIntStubs = {
     TclCopyChannel, /* 248 */
     TclDoubleDigits, /* 249 */
     TclSetSlaveCancelFlags, /* 250 */
+    TclRegisterLiteral, /* 251 */
 };
 
 static const TclIntPlatStubs tclIntPlatStubs = {
     TCL_STUB_MAGIC,
     0,
-#if !defined(__WIN32__) && !defined(__CYGWIN__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(__CYGWIN__) && !defined(MAC_OSX_TCL) /* UNIX */
     TclGetAndDetachPids, /* 0 */
     TclpCloseFile, /* 1 */
     TclpCreateCommandChannel, /* 2 */
@@ -589,7 +590,7 @@ static const TclIntPlatStubs tclIntPlatStubs = {
     TclWinCPUID, /* 29 */
     TclUnixOpenTemporaryFile, /* 30 */
 #endif /* UNIX */
-#if defined(__WIN32__) || defined(__CYGWIN__) /* WIN */
+#if defined(_WIN32) || defined(__CYGWIN__) /* WIN */
     TclWinConvertError, /* 0 */
     TclWinConvertWSAError, /* 1 */
     TclWinGetServByName, /* 2 */
@@ -660,7 +661,7 @@ static const TclIntPlatStubs tclIntPlatStubs = {
 static const TclPlatStubs tclPlatStubs = {
     TCL_STUB_MAGIC,
     0,
-#if defined(__WIN32__) || defined(__CYGWIN__) /* WIN */
+#if defined(_WIN32) || defined(__CYGWIN__) /* WIN */
     Tcl_WinUtfToTChar, /* 0 */
     Tcl_WinTCharToUtf, /* 1 */
 #endif /* WIN */
@@ -757,19 +758,19 @@ const TclStubs tclStubs = {
     Tcl_DbCkalloc, /* 6 */
     Tcl_DbCkfree, /* 7 */
     Tcl_DbCkrealloc, /* 8 */
-#if !defined(__WIN32__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(MAC_OSX_TCL) /* UNIX */
     Tcl_CreateFileHandler, /* 9 */
 #endif /* UNIX */
-#if defined(__WIN32__) /* WIN */
+#if defined(_WIN32) /* WIN */
     0, /* 9 */
 #endif /* WIN */
 #ifdef MAC_OSX_TCL /* MACOSX */
     Tcl_CreateFileHandler, /* 9 */
 #endif /* MACOSX */
-#if !defined(__WIN32__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(MAC_OSX_TCL) /* UNIX */
     Tcl_DeleteFileHandler, /* 10 */
 #endif /* UNIX */
-#if defined(__WIN32__) /* WIN */
+#if defined(_WIN32) /* WIN */
     0, /* 10 */
 #endif /* WIN */
 #ifdef MAC_OSX_TCL /* MACOSX */
@@ -931,10 +932,10 @@ const TclStubs tclStubs = {
     Tcl_GetMaster, /* 164 */
     Tcl_GetNameOfExecutable, /* 165 */
     Tcl_GetObjResult, /* 166 */
-#if !defined(__WIN32__) && !defined(MAC_OSX_TCL) /* UNIX */
+#if !defined(_WIN32) && !defined(MAC_OSX_TCL) /* UNIX */
     Tcl_GetOpenFile, /* 167 */
 #endif /* UNIX */
-#if defined(__WIN32__) /* WIN */
+#if defined(_WIN32) /* WIN */
     0, /* 167 */
 #endif /* WIN */
 #ifdef MAC_OSX_TCL /* MACOSX */
diff --git a/generic/tclTest.c b/generic/tclTest.c
index f121d0d..a27c95a 100644
--- a/generic/tclTest.c
+++ b/generic/tclTest.c
@@ -414,7 +414,7 @@ static int		TestNRELevels(ClientData clientData,
 static int		TestInterpResolverCmd(ClientData clientData,
 			    Tcl_Interp *interp, int objc,
 			    Tcl_Obj *const objv[]);
-#if defined(HAVE_CPUID) || defined(__WIN32__)
+#if defined(HAVE_CPUID) || defined(_WIN32)
 static int		TestcpuidCmd(ClientData dummy,
 			    Tcl_Interp* interp, int objc,
 			    Tcl_Obj *const objv[]);
@@ -681,7 +681,7 @@ Tcltest_Init(
 	    NULL, NULL);
     Tcl_CreateCommand(interp, "testexitmainloop", TestexitmainloopCmd,
 	    NULL, NULL);
-#if defined(HAVE_CPUID) || defined(__WIN32__)
+#if defined(HAVE_CPUID) || defined(_WIN32)
     Tcl_CreateObjCommand(interp, "testcpuid", TestcpuidCmd,
 	    (ClientData) 0, NULL);
 #endif
@@ -6648,7 +6648,7 @@ TestNumUtfCharsCmd(
     return TCL_OK;
 }
 
-#if defined(HAVE_CPUID) || defined(__WIN32__)
+#if defined(HAVE_CPUID) || defined(_WIN32)
 /*
  *----------------------------------------------------------------------
  *
diff --git a/generic/tclThreadJoin.c b/generic/tclThreadJoin.c
index 4b09e1c..5c70a62 100644
--- a/generic/tclThreadJoin.c
+++ b/generic/tclThreadJoin.c
@@ -14,7 +14,7 @@
 
 #include "tclInt.h"
 
-#ifdef WIN32
+#ifdef _WIN32
 
 /*
  * The information about each joinable thread is remembered in a structure as
@@ -305,7 +305,7 @@ TclSignalExitThread(
 
     Tcl_MutexUnlock(&threadPtr->threadMutex);
 }
-#endif /* WIN32 */
+#endif /* _WIN32 */
 
 /*
  * Local Variables:
diff --git a/generic/tclUtil.c b/generic/tclUtil.c
index b089132..2d00adf 100644
--- a/generic/tclUtil.c
+++ b/generic/tclUtil.c
@@ -14,6 +14,7 @@
 
 #include "tclInt.h"
 #include "tclParse.h"
+#include "tclStringTrim.h"
 #include <math.h>
 
 /*
@@ -1768,8 +1769,7 @@ TclTrimLeft(
  */
 
 /* The whitespace characters trimmed during [concat] operations */
-#define CONCAT_WS " \f\v\r\t\n"
-#define CONCAT_WS_SIZE (int) (sizeof(CONCAT_WS "") - 1)
+#define CONCAT_WS_SIZE (int) (sizeof(CONCAT_TRIM_SET "") - 1)
 
 char *
 Tcl_Concat(
@@ -1825,7 +1825,8 @@ Tcl_Concat(
 	 * Trim away the leading whitespace.
 	 */
 
-	trim = TclTrimLeft(element, elemLength, CONCAT_WS, CONCAT_WS_SIZE);
+	trim = TclTrimLeft(element, elemLength, CONCAT_TRIM_SET,
+		CONCAT_WS_SIZE);
 	element += trim;
 	elemLength -= trim;
 
@@ -1834,7 +1835,8 @@ Tcl_Concat(
 	 * a final backslash character.
 	 */
 
-	trim = TclTrimRight(element, elemLength, CONCAT_WS, CONCAT_WS_SIZE);
+	trim = TclTrimRight(element, elemLength, CONCAT_TRIM_SET,
+		CONCAT_WS_SIZE);
 	trim -= trim && (element[elemLength - trim - 1] == '\\');
 	elemLength -= trim;
 
@@ -1959,7 +1961,8 @@ Tcl_ConcatObj(
 	 * Trim away the leading whitespace.
 	 */
 
-	trim = TclTrimLeft(element, elemLength, CONCAT_WS, CONCAT_WS_SIZE);
+	trim = TclTrimLeft(element, elemLength, CONCAT_TRIM_SET,
+		CONCAT_WS_SIZE);
 	element += trim;
 	elemLength -= trim;
 
@@ -1968,7 +1971,8 @@ Tcl_ConcatObj(
 	 * a final backslash character.
 	 */
 
-	trim = TclTrimRight(element, elemLength, CONCAT_WS, CONCAT_WS_SIZE);
+	trim = TclTrimRight(element, elemLength, CONCAT_TRIM_SET,
+		CONCAT_WS_SIZE);
 	trim -= trim && (element[elemLength - trim - 1] == '\\');
 	elemLength -= trim;