Hive off the ensemble code into its own file.

Split the [switch] compiler for sanity's sake.

10 files changed, 3623 insertions, 3505 deletions

diff --git a/ChangeLog b/ChangeLog
index e48cc1d..6585b03 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,13 +1,23 @@
+2010-02-13  Donal K. Fellows  <dkf@users.sf.net>
+
+	* generic/tclCompCmds.c (TclCompileSwitchCmd): Divided the [switch]
+	compiler into three pieces (after the model of [try]): a parser, an
+	instruction-issuer for chained tests, and an instruction-issuer for
+	jump tables.
+
+	* generic/tclEnsemble.c: Split the ensemble engine out into its own
+	file rather than keeping it mashed together with the namespace code.
+
 2010-02-12  Jan Nijtmans  <nijtmans@users.sf.net>
 
-    * win/tcl.m4           use -pipe for gcc on win32
-    * win/configure        (mingw/cygwin) (regenerated)
-    * win/.cvsignore       Add .lib, .exp and .res here
+	* win/tcl.m4:		Use -pipe for gcc on win32
+	* win/configure:	(mingw/cygwin) (regenerated)
+	* win/.cvsignore:	Add .lib, .exp and .res here
 
 2010-02-11  Mo DeJong  <mdejong@users.sourceforge.net>
 
-	* tests/list.test: Add tests for explicit \0 in
-	a string argument to the list command.
+	* tests/list.test: Add tests for explicit \0 in a string argument to
+	the list command.
 
 2010-02-11  Donal K. Fellows  <dkf@users.sf.net>
 
diff --git a/generic/tclCompCmds.c b/generic/tclCompCmds.c
index d2693dc..b9cf5f6 100644
--- a/generic/tclCompCmds.c
+++ b/generic/tclCompCmds.c
@@ -12,138 +12,13 @@
  * See the file "license.terms" for information on usage and redistribution of
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclCompCmds.c,v 1.161 2010/02/09 22:20:27 dkf Exp $
+ * RCS: @(#) $Id: tclCompCmds.c,v 1.162 2010/02/13 18:11:05 dkf Exp $
  */
 
 #include "tclInt.h"
 #include "tclCompile.h"
 
 /*
- * Macro that encapsulates an efficiency trick that avoids a function call for
- * the simplest of compiles. The ANSI C "prototype" for this macro is:
- *
- * static void		CompileWord(CompileEnv *envPtr, Tcl_Token *tokenPtr,
- *			    Tcl_Interp *interp, int word);
- */
-
-#define CompileWord(envPtr, tokenPtr, interp, word) \
-    if ((tokenPtr)->type == TCL_TOKEN_SIMPLE_WORD) {			\
-	TclEmitPush(TclRegisterNewLiteral((envPtr), (tokenPtr)[1].start, \
-		(tokenPtr)[1].size), (envPtr));				\
-    } else {								\
-	envPtr->line = mapPtr->loc[eclIndex].line[word];		\
-	envPtr->clNext = mapPtr->loc[eclIndex].next[word];		\
-	TclCompileTokens((interp), (tokenPtr)+1, (tokenPtr)->numComponents, \
-		(envPtr));						\
-    }
-
-/*
- * TIP #280: Remember the per-word line information of the current command. An
- * index is used instead of a pointer as recursive compilation may reallocate,
- * i.e. move, the array. This is also the reason to save the nuloc now, it may
- * change during the course of the function.
- *
- * Macro to encapsulate the variable definition and setup.
- */
-
-#define DefineLineInformation \
-    ExtCmdLoc *mapPtr = envPtr->extCmdMapPtr; \
-    int eclIndex = mapPtr->nuloc - 1
-
-#define SetLineInformation(word) \
-    envPtr->line   = mapPtr->loc [eclIndex].line [(word)]; \
-    envPtr->clNext = mapPtr->loc [eclIndex].next [(word)]
-
-/*
- * Convenience macro for use when compiling bodies of commands. The ANSI C
- * "prototype" for this macro is:
- *
- * static void		CompileBody(CompileEnv *envPtr, Tcl_Token *tokenPtr,
- *			    Tcl_Interp *interp);
- */
-
-#define CompileBody(envPtr, tokenPtr, interp) \
-    TclCompileCmdWord((interp), (tokenPtr)+1, (tokenPtr)->numComponents, \
-	    (envPtr))
-
-/*
- * Convenience macro for use when compiling tokens to be pushed. The ANSI C
- * "prototype" for this macro is:
- *
- * static void		CompileTokens(CompileEnv *envPtr, Tcl_Token *tokenPtr,
- *			    Tcl_Interp *interp);
- */
-
-#define CompileTokens(envPtr, tokenPtr, interp) \
-    TclCompileTokens((interp), (tokenPtr)+1, (tokenPtr)->numComponents, \
-	    (envPtr));
-/*
- * Convenience macro for use when pushing literals. The ANSI C "prototype" for
- * this macro is:
- *
- * static void		PushLiteral(CompileEnv *envPtr,
- *			    const char *string, int length);
- */
-
-#define PushLiteral(envPtr, string, length) \
-    TclEmitPush(TclRegisterNewLiteral((envPtr), (string), (length)), (envPtr))
-
-/*
- * Macro to advance to the next token; it is more mnemonic than the address
- * arithmetic that it replaces. The ANSI C "prototype" for this macro is:
- *
- * static Tcl_Token *	TokenAfter(Tcl_Token *tokenPtr);
- */
-
-#define TokenAfter(tokenPtr) \
-    ((tokenPtr) + ((tokenPtr)->numComponents + 1))
-
-/*
- * Macro to get the offset to the next instruction to be issued. The ANSI C
- * "prototype" for this macro is:
- *
- * static int	CurrentOffset(CompileEnv *envPtr);
- */
-
-#define CurrentOffset(envPtr) \
-    ((envPtr)->codeNext - (envPtr)->codeStart)
-
-/*
- * Note: the exceptDepth is a bit of a misnomer: TEBC only needs the
- * maximal depth of nested CATCH ranges in order to alloc runtime
- * memory. These macros should compute precisely that? OTOH, the nesting depth
- * of LOOP ranges is an interesting datum for debugging purposes, and that is
- * what we compute now.
- *
- * static int	DeclareExceptionRange(CompileEnv *envPtr, int type);
- * static int	ExceptionRangeStarts(CompileEnv *envPtr, int index);
- * static void	ExceptionRangeEnds(CompileEnv *envPtr, int index);
- * static void	ExceptionRangeTarget(CompileEnv *envPtr, int index, LABEL);
- */
-
-#define DeclareExceptionRange(envPtr, type) \
-    (TclCreateExceptRange((type), (envPtr)))
-#define ExceptionRangeStarts(envPtr, index) \
-    (((envPtr)->exceptDepth++),						\
-    ((envPtr)->maxExceptDepth =						\
-	    TclMax((envPtr)->exceptDepth, (envPtr)->maxExceptDepth)),	\
-    ((envPtr)->exceptArrayPtr[(index)].codeOffset = CurrentOffset(envPtr)))
-#define ExceptionRangeEnds(envPtr, index) \
-    (((envPtr)->exceptDepth--),						\
-    ((envPtr)->exceptArrayPtr[(index)].numCodeBytes =			\
-	CurrentOffset(envPtr) - (envPtr)->exceptArrayPtr[(index)].codeOffset))
-#define ExceptionRangeTarget(envPtr, index, targetType) \
-    ((envPtr)->exceptArrayPtr[(index)].targetType = CurrentOffset(envPtr))
-
-/*
- * Check if there is an LVT for compiled locals
- */
-
-#define EnvHasLVT(envPtr) \
-    (envPtr->procPtr || envPtr->iPtr->varFramePtr->localCachePtr)
-
-
-/*
  * Prototypes for procedures defined later in this file:
  */
 
@@ -182,6 +57,18 @@ static int		CompileUnaryOpCmd(Tcl_Interp *interp,
 static void		CompileReturnInternal(CompileEnv *envPtr,
 			    unsigned char op, int code, int level,
 			    Tcl_Obj *returnOpts);
+static void		IssueSwitchChainedTests(Tcl_Interp *interp,
+			    CompileEnv *envPtr, ExtCmdLoc *mapPtr,
+			    int eclIndex, int mode, int noCase,
+			    int valueIndex, Tcl_Token *valueTokenPtr,
+			    int numWords, Tcl_Token **bodyToken,
+			    int *bodyLines, int **bodyNext);
+static void		IssueSwitchJumpTable(Tcl_Interp *interp,
+			    CompileEnv *envPtr, ExtCmdLoc *mapPtr,
+			    int eclIndex, int valueIndex,
+			    Tcl_Token *valueTokenPtr, int numWords,
+			    Tcl_Token **bodyToken, int *bodyLines,
+			    int **bodyContLines);
 static int		IssueTryFinallyInstructions(Tcl_Interp *interp,
 			    CompileEnv *envPtr, Tcl_Token *bodyToken,
 			    int numHandlers, int *matchCodes,
@@ -194,6 +81,42 @@ static int		IssueTryInstructions(Tcl_Interp *interp,
 			    Tcl_Obj **matchClauses, int *resultVarIndices,
 			    int *optionVarIndices, Tcl_Token **handlerTokens);
 
+/*
+ * Macro that encapsulates an efficiency trick that avoids a function call for
+ * the simplest of compiles. The ANSI C "prototype" for this macro is:
+ *
+ * static void		CompileWord(CompileEnv *envPtr, Tcl_Token *tokenPtr,
+ *			    Tcl_Interp *interp, int word);
+ */
+
+#define CompileWord(envPtr, tokenPtr, interp, word) \
+    if ((tokenPtr)->type == TCL_TOKEN_SIMPLE_WORD) {			\
+	TclEmitPush(TclRegisterNewLiteral((envPtr), (tokenPtr)[1].start, \
+		(tokenPtr)[1].size), (envPtr));				\
+    } else {								\
+	envPtr->line = mapPtr->loc[eclIndex].line[word];		\
+	envPtr->clNext = mapPtr->loc[eclIndex].next[word];		\
+	TclCompileTokens((interp), (tokenPtr)+1, (tokenPtr)->numComponents, \
+		(envPtr));						\
+    }
+
+/*
+ * TIP #280: Remember the per-word line information of the current command. An
+ * index is used instead of a pointer as recursive compilation may reallocate,
+ * i.e. move, the array. This is also the reason to save the nuloc now, it may
+ * change during the course of the function.
+ *
+ * Macro to encapsulate the variable definition and setup.
+ */
+
+#define DefineLineInformation \
+    ExtCmdLoc *mapPtr = envPtr->extCmdMapPtr;				\
+    int eclIndex = mapPtr->nuloc - 1
+
+#define SetLineInformation(word) \
+    envPtr->line = mapPtr->loc[eclIndex].line[(word)];			\
+    envPtr->clNext = mapPtr->loc[eclIndex].next[(word)]
+
 #define PushVarNameWord(i,v,e,f,l,s,sc,word) \
     PushVarName(i,v,e,f,l,s,sc,						\
 	    mapPtr->loc[eclIndex].line[(word)],				\
@@ -4227,33 +4150,19 @@ TclCompileSwitchCmd(
 {
     Tcl_Token *tokenPtr;	/* Pointer to tokens in command. */
     int numWords;		/* Number of words in command. */
-
     Tcl_Token *valueTokenPtr;	/* Token for the value to switch on. */
     enum {Switch_Exact, Switch_Glob, Switch_Regexp} mode;
 				/* What kind of switch are we doing? */
-
     Tcl_Token *bodyTokenArray;	/* Array of real pattern list items. */
     Tcl_Token **bodyToken;	/* Array of pointers to pattern list items. */
     int *bodyLines;		/* Array of line numbers for body list
 				 * items. */
-    int **bodyNext;
-    int foundDefault;		/* Flag to indicate whether a "default" clause
-				 * is present. */
-
-    JumpFixup *fixupArray;	/* Array of forward-jump fixup records. */
-    int *fixupTargetArray;	/* Array of places for fixups to point at. */
-    int fixupCount;		/* Number of places to fix up. */
-    int contFixIndex;		/* Where the first of the jumps due to a group
-				 * of continuation bodies starts, or -1 if
-				 * there aren't any. */
-    int contFixCount;		/* Number of continuation bodies pointing to
-				 * the current (or next) real body. */
-
-    int savedStackDepth = envPtr->currStackDepth;
+    int **bodyContLines;	/* Array of continuation line info. */
     int noCase;			/* Has the -nocase flag been given? */
     int foundMode = 0;		/* Have we seen a mode flag yet? */
     int isListedArms = 0;
     int i, valueIndex;
+    int result = TCL_ERROR;
     DefineLineInformation;	/* TIP #280 */
     int *clNext = envPtr->clNext;
 
@@ -4434,7 +4343,7 @@ TclCompileSwitchCmd(
 	bodyTokenArray = (Tcl_Token *) ckalloc(sizeof(Tcl_Token) * numWords);
 	bodyToken = (Tcl_Token **) ckalloc(sizeof(Tcl_Token *) * numWords);
 	bodyLines = (int *) ckalloc(sizeof(int) * numWords);
-	bodyNext = (int **) ckalloc(sizeof(int*) * numWords);
+	bodyContLines = (int **) ckalloc(sizeof(int*) * numWords);
 
 	/*
 	 * Locate the start of the arms within the overall word.
@@ -4475,11 +4384,7 @@ TclCompileSwitchCmd(
 		    (tokenStartPtr < tokenPtr[1].start+tokenPtr[1].size
 		    && !isspace(UCHAR(*tokenStartPtr)))) {
 		ckfree((char *) argv);
-		ckfree((char *) bodyToken);
-		ckfree((char *) bodyTokenArray);
-		ckfree((char *) bodyLines);
-		ckfree((char *) bodyNext);
-		return TCL_ERROR;
+		goto freeTemporaries;
 	    }
 
 	    /*
@@ -4492,7 +4397,7 @@ TclCompileSwitchCmd(
 	    TclAdvanceContinuations(&bline, &clNext,
 		    bodyTokenArray[i].start - envPtr->source);
 	    bodyLines[i] = bline;
-	    bodyNext[i] = clNext;
+	    bodyContLines[i] = clNext;
 	    p = bodyTokenArray[i].start;
 
 	    while (isspace(UCHAR(*tokenStartPtr))) {
@@ -4517,11 +4422,7 @@ TclCompileSwitchCmd(
 	 */
 
 	if (tokenStartPtr != tokenPtr[1].start+tokenPtr[1].size) {
-	    ckfree((char *) bodyToken);
-	    ckfree((char *) bodyTokenArray);
-	    ckfree((char *) bodyLines);
-	    ckfree((char *) bodyNext);
-	    return TCL_ERROR;
+	    goto freeTemporaries;
 	}
 
     } else if (numWords % 2 || numWords == 0) {
@@ -4541,7 +4442,7 @@ TclCompileSwitchCmd(
 
 	bodyToken = (Tcl_Token **) ckalloc(sizeof(Tcl_Token *) * numWords);
 	bodyLines = (int *) ckalloc(sizeof(int) * numWords);
-	bodyNext = (int **) ckalloc(sizeof(int*) * numWords);
+	bodyContLines = (int **) ckalloc(sizeof(int*) * numWords);
 	bodyTokenArray = NULL;
 	for (i=0 ; i<numWords ; i++) {
 	    /*
@@ -4552,10 +4453,7 @@ TclCompileSwitchCmd(
 
 	    if (tokenPtr->type != TCL_TOKEN_SIMPLE_WORD ||
 		    tokenPtr->numComponents != 1) {
-		ckfree((char *) bodyToken);
-		ckfree((char *) bodyLines);
-		ckfree((char *) bodyNext);
-		return TCL_ERROR;
+		goto freeTemporaries;
 	    }
 	    bodyToken[i] = tokenPtr+1;
 
@@ -4564,7 +4462,7 @@ TclCompileSwitchCmd(
 	     */
 
 	    bodyLines[i] = mapPtr->loc[eclIndex].line[valueIndex+1+i];
-	    bodyNext[i] = mapPtr->loc[eclIndex].next[valueIndex+1+i];
+	    bodyContLines[i] = mapPtr->loc[eclIndex].next[valueIndex+1+i];
 	    tokenPtr = TokenAfter(tokenPtr);
 	}
     }
@@ -4576,200 +4474,98 @@ TclCompileSwitchCmd(
 
     if (bodyToken[numWords-1]->size == 1 &&
 	    bodyToken[numWords-1]->start[0] == '-') {
-	ckfree((char *) bodyToken);
-	ckfree((char *) bodyLines);
-	ckfree((char *) bodyNext);
-	if (bodyTokenArray != NULL) {
-	    ckfree((char *) bodyTokenArray);
-	}
-	return TCL_ERROR;
+	goto freeTemporaries;
     }
 
     /*
      * Now we commit to generating code; the parsing stage per se is done.
-     * First, we push the value we're matching against on the stack.
-     */
-
-    SetLineInformation(valueIndex);
-    CompileTokens(envPtr, valueTokenPtr, interp);
-
-    /*
      * Check if we can generate a jump table, since if so that's faster than
      * doing an explicit compare with each body. Note that we're definitely
      * over-conservative with determining whether we can do the jump table,
      * but it handles the most common case well enough.
      */
 
-    if (isListedArms && mode == Switch_Exact && !noCase) {
-	JumptableInfo *jtPtr;
-	int infoIndex, isNew, *finalFixups, numRealBodies = 0, jumpLocation;
-	int mustGenerate, jumpToDefault;
-	Tcl_DString buffer;
-	Tcl_HashEntry *hPtr;
-
-	/*
-	 * Compile the switch by using a jump table, which is basically a
-	 * hashtable that maps from literal values to match against to the
-	 * offset (relative to the INST_JUMP_TABLE instruction) to jump to.
-	 * The jump table itself is independent of any invokation of the
-	 * bytecode, and as such is stored in an auxData block.
-	 *
-	 * Start by allocating the jump table itself, plus some workspace.
-	 */
-
-	jtPtr = (JumptableInfo *) ckalloc(sizeof(JumptableInfo));
-	Tcl_InitHashTable(&jtPtr->hashTable, TCL_STRING_KEYS);
-	infoIndex = TclCreateAuxData(jtPtr, &tclJumptableInfoType, envPtr);
-	finalFixups = (int *) ckalloc(sizeof(int) * (numWords/2));
-	foundDefault = 0;
-	mustGenerate = 1;
-
-	/*
-	 * Next, issue the instruction to do the jump, together with what we
-	 * want to do if things do not work out (jump to either the default
-	 * clause or the "default" default, which just sets the result to
-	 * empty). Note that we will come back and rewrite the jump's offset
-	 * parameter when we know what it should be, and that all jumps we
-	 * issue are of the wide kind because that makes the code much easier
-	 * to debug!
-	 */
-
-	jumpLocation = CurrentOffset(envPtr);
-	TclEmitInstInt4(INST_JUMP_TABLE, infoIndex, envPtr);
-	jumpToDefault = CurrentOffset(envPtr);
-	TclEmitInstInt4(INST_JUMP4, 0, envPtr);
-
-	for (i=0 ; i<numWords ; i+=2) {
-	    /*
-	     * For each arm, we must first work out what to do with the match
-	     * term.
-	     */
-
-	    if (i!=numWords-2 || bodyToken[numWords-2]->size != 7 ||
-		    memcmp(bodyToken[numWords-2]->start, "default", 7)) {
-		/*
-		 * This is not a default clause, so insert the current
-		 * location as a target in the jump table (assuming it isn't
-		 * already there, which would indicate that this clause is
-		 * probably masked by an earlier one). Note that we use a
-		 * Tcl_DString here simply because the hash API does not let
-		 * us specify the string length.
-		 */
-
-		Tcl_DStringInit(&buffer);
-		Tcl_DStringAppend(&buffer, bodyToken[i]->start,
-			bodyToken[i]->size);
-		hPtr = Tcl_CreateHashEntry(&jtPtr->hashTable,
-			Tcl_DStringValue(&buffer), &isNew);
-		if (isNew) {
-		    /*
-		     * First time we've encountered this match clause, so it
-		     * must point to here.
-		     */
-
-		    Tcl_SetHashValue(hPtr, (ClientData)
-			    (CurrentOffset(envPtr) - jumpLocation));
-		}
-		Tcl_DStringFree(&buffer);
-	    } else {
-		/*
-		 * This is a default clause, so patch up the fallthrough from
-		 * the INST_JUMP_TABLE instruction to here.
-		 */
-
-		foundDefault = 1;
-		isNew = 1;
-		TclStoreInt4AtPtr(CurrentOffset(envPtr)-jumpToDefault,
-			envPtr->codeStart+jumpToDefault+1);
-	    }
-
-	    /*
-	     * Now, for each arm we must deal with the body of the clause.
-	     *
-	     * If this is a continuation body (never true of a final clause,
-	     * whether default or not) we're done because the next jump target
-	     * will also point here, so we advance to the next clause.
-	     */
-
-	    if (bodyToken[i+1]->size == 1 && bodyToken[i+1]->start[0] == '-') {
-		mustGenerate = 1;
-		continue;
-	    }
-
-	    /*
-	     * Also skip this arm if its only match clause is masked. (We
-	     * could probably be more aggressive about this, but that would be
-	     * much more difficult to get right.)
-	     */
-
-	    if (!isNew && !mustGenerate) {
-		continue;
-	    }
-	    mustGenerate = 0;
-
-	    /*
-	     * Compile the body of the arm.
-	     */
-
-	    envPtr->line = bodyLines[i+1];	/* TIP #280 */
-	    envPtr->clNext = bodyNext[i+1];	/* TIP #280 */
-	    TclCompileCmdWord(interp, bodyToken[i+1], 1, envPtr);
-
-	    /*
-	     * Compile a jump in to the end of the command if this body is
-	     * anything other than a user-supplied default arm (to either skip
-	     * over the remaining bodies or the code that generates an empty
-	     * result).
-	     */
-
-	    if (i+2 < numWords || !foundDefault) {
-		finalFixups[numRealBodies++] = CurrentOffset(envPtr);
-
-		/*
-		 * Easier by far to issue this jump as a fixed-width jump.
-		 * Otherwise we'd need to do a lot more (and more awkward)
-		 * rewriting when we fixed this all up.
-		 */
-
-		TclEmitInstInt4(INST_JUMP4, 0, envPtr);
-	    }
-	}
-
-	/*
-	 * We're at the end. If we've not already done so through the
-	 * processing of a user-supplied default clause, add in a "default"
-	 * default clause now.
-	 */
+    if ((isListedArms) && (mode == Switch_Exact) && (!noCase)) {
+	IssueSwitchJumpTable(interp, envPtr, mapPtr, eclIndex, valueIndex,
+		valueTokenPtr, numWords, bodyToken, bodyLines, bodyContLines);
+    } else {
+	IssueSwitchChainedTests(interp, envPtr, mapPtr, eclIndex, mode,noCase,
+		valueIndex, valueTokenPtr, numWords, bodyToken, bodyLines,
+		bodyContLines);
+    }
+    result = TCL_OK;
 
-	if (!foundDefault) {
-	    TclStoreInt4AtPtr(CurrentOffset(envPtr)-jumpToDefault,
-		    envPtr->codeStart+jumpToDefault+1);
-	    PushLiteral(envPtr, "", 0);
-	}
+    /*
+     * Clean up all our temporary space and return.
+     */
 
-	/*
-	 * No more instructions to be issued; everything that needs to jump to
-	 * the end of the command is fixed up at this point.
-	 */
+  freeTemporaries:
+    ckfree((char *) bodyToken);
+    ckfree((char *) bodyLines);
+    ckfree((char *) bodyContLines);
+    if (bodyTokenArray != NULL) {
+	ckfree((char *) bodyTokenArray);
+    }
+    return result;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * IssueSwitchChainedTests --
+ *
+ *	Generate instructions for a [switch] command that is to be compiled
+ *	into a sequence of tests. This is the generic handle-everything mode
+ *	that inherently has performance that is (on average) linear in the
+ *	number of tests. It is the only mode that can handle -glob and -regexp
+ *	matches, or anything that is case-insensitive. It does not handle the
+ *	wild-and-wooly end of regexp matching (i.e., capture of match results)
+ *	so that's when we spill to the interpreted version.
+ *
+ *----------------------------------------------------------------------
+ */
 
-	for (i=0 ; i<numRealBodies ; i++) {
-	    TclStoreInt4AtPtr(CurrentOffset(envPtr)-finalFixups[i],
-		    envPtr->codeStart+finalFixups[i]+1);
-	}
+static void
+IssueSwitchChainedTests(
+    Tcl_Interp *interp,		/* Context for compiling script bodies. */
+    CompileEnv *envPtr,		/* Holds resulting instructions. */
+    ExtCmdLoc *mapPtr,		/* For mapping tokens to their source code
+				 * location. */
+    int eclIndex,
+    int mode,			/* Exact, Glob or Regexp */
+    int noCase,			/* Case-insensitivity flag. */
+    int valueIndex,		/* The value to match against. */
+    Tcl_Token *valueTokenPtr,
+    int numBodyTokens,		/* Number of tokens describing things the
+				 * switch can match against and bodies to
+				 * execute when the match succeeds. */
+    Tcl_Token **bodyToken,	/* Array of pointers to pattern list items. */
+    int *bodyLines,		/* Array of line numbers for body list
+				 * items. */
+    int **bodyContLines)	/* Array of continuation line info. */
+{
+    enum {Switch_Exact, Switch_Glob, Switch_Regexp};
+    int savedStackDepth = envPtr->currStackDepth;
+    int foundDefault;		/* Flag to indicate whether a "default" clause
+				 * is present. */
+    JumpFixup *fixupArray;	/* Array of forward-jump fixup records. */
+    int *fixupTargetArray;	/* Array of places for fixups to point at. */
+    int fixupCount;		/* Number of places to fix up. */
+    int contFixIndex;		/* Where the first of the jumps due to a group
+				 * of continuation bodies starts, or -1 if
+				 * there aren't any. */
+    int contFixCount;		/* Number of continuation bodies pointing to
+				 * the current (or next) real body. */
+    int nextArmFixupIndex;
+    int simple, exact;		/* For extracting the type of regexp. */
+    int i;
 
-	/*
-	 * Clean up all our temporary space and return.
-	 */
+    /*
+     * First, we push the value we're matching against on the stack.
+     */
 
-	ckfree((char *) finalFixups);
-	ckfree((char *) bodyToken);
-	ckfree((char *) bodyLines);
-	ckfree((char *) bodyNext);
-	if (bodyTokenArray != NULL) {
-	    ckfree((char *) bodyTokenArray);
-	}
-	return TCL_OK;
-    }
+    SetLineInformation(valueIndex);
+    CompileTokens(envPtr, valueTokenPtr, interp);
 
     /*
      * Generate a test for each arm.
@@ -4777,34 +4573,33 @@ TclCompileSwitchCmd(
 
     contFixIndex = -1;
     contFixCount = 0;
-    fixupArray = (JumpFixup *) ckalloc(sizeof(JumpFixup) * numWords);
-    fixupTargetArray = (int *) ckalloc(sizeof(int) * numWords);
-    memset(fixupTargetArray, 0, numWords * sizeof(int));
+    fixupArray = TclStackAlloc(interp, sizeof(JumpFixup) * numBodyTokens);
+    fixupTargetArray = TclStackAlloc(interp, sizeof(int) * numBodyTokens);
+    memset(fixupTargetArray, 0, numBodyTokens * sizeof(int));
     fixupCount = 0;
     foundDefault = 0;
-    for (i=0 ; i<numWords ; i+=2) {
-	int nextArmFixupIndex = -1;
-
+    for (i=0 ; i<numBodyTokens ; i+=2) {
+	nextArmFixupIndex = -1;
 	envPtr->currStackDepth = savedStackDepth + 1;
-	if (i!=numWords-2 || bodyToken[numWords-2]->size != 7 ||
-		memcmp(bodyToken[numWords-2]->start, "default", 7)) {
+	if (i!=numBodyTokens-2 || bodyToken[numBodyTokens-2]->size != 7 ||
+		memcmp(bodyToken[numBodyTokens-2]->start, "default", 7)) {
 	    /*
 	     * Generate the test for the arm.
 	     */
 
 	    switch (mode) {
 	    case Switch_Exact:
-		TclEmitOpcode(INST_DUP, envPtr);
-		TclCompileTokens(interp, bodyToken[i], 1, envPtr);
-		TclEmitOpcode(INST_STR_EQ, envPtr);
+		TclEmitOpcode(INST_DUP,				envPtr);
+		TclCompileTokens(interp, bodyToken[i], 1,	envPtr);
+		TclEmitOpcode(INST_STR_EQ,			envPtr);
 		break;
 	    case Switch_Glob:
-		TclCompileTokens(interp, bodyToken[i], 1, envPtr);
-		TclEmitInstInt4(INST_OVER, 1, envPtr);
-		TclEmitInstInt1(INST_STR_MATCH, noCase, envPtr);
+		TclCompileTokens(interp, bodyToken[i], 1,	envPtr);
+		TclEmitInstInt4(INST_OVER, 1,			envPtr);
+		TclEmitInstInt1(INST_STR_MATCH, noCase,		envPtr);
 		break;
-	    case Switch_Regexp: {
-		int simple = 0, exact = 0;
+	    case Switch_Regexp:
+		simple = exact = 0;
 
 		/*
 		 * Keep in sync with TclCompileRegexpCmd.
@@ -4840,14 +4635,8 @@ TclCompileSwitchCmd(
 		    TclCompileTokens(interp, bodyToken[i], 1, envPtr);
 		}
 
-		TclEmitInstInt4(INST_OVER, 1, envPtr);
-		if (simple) {
-		    if (exact && !noCase) {
-			TclEmitOpcode(INST_STR_EQ, envPtr);
-		    } else {
-			TclEmitInstInt1(INST_STR_MATCH, noCase, envPtr);
-		    }
-		} else {
+		TclEmitInstInt4(INST_OVER, 1,			envPtr);
+		if (!simple) {
 		    /*
 		     * Pass correct RE compile flags. We use only Int1
 		     * (8-bit), but that handles all the flags we want to
@@ -4858,10 +4647,13 @@ TclCompileSwitchCmd(
 		    int cflags = TCL_REG_ADVANCED
 			    | (noCase ? TCL_REG_NOCASE : 0);
 
-		    TclEmitInstInt1(INST_REGEXP, cflags, envPtr);
+		    TclEmitInstInt1(INST_REGEXP, cflags,	envPtr);
+		} else if (exact && !noCase) {
+		    TclEmitOpcode(INST_STR_EQ,			envPtr);
+		} else {
+		    TclEmitInstInt1(INST_STR_MATCH, noCase,	envPtr);
 		}
 		break;
-	    }
 	    default:
 		Tcl_Panic("unknown switch mode: %d", mode);
 	    }
@@ -4878,13 +4670,14 @@ TclCompileSwitchCmd(
 		    contFixCount = 0;
 		}
 		TclEmitForwardJump(envPtr, TCL_TRUE_JUMP,
-			fixupArray+contFixIndex+contFixCount);
+			&fixupArray[contFixIndex+contFixCount]);
 		fixupCount++;
 		contFixCount++;
 		continue;
 	    }
 
-	    TclEmitForwardJump(envPtr, TCL_FALSE_JUMP, fixupArray+fixupCount);
+	    TclEmitForwardJump(envPtr, TCL_FALSE_JUMP,
+		    &fixupArray[fixupCount]);
 	    nextArmFixupIndex = fixupCount;
 	    fixupCount++;
 	} else {
@@ -4923,32 +4716,21 @@ TclCompileSwitchCmd(
 	 * pattern.
 	 */
 
-	TclEmitOpcode(INST_POP, envPtr);
+	TclEmitOpcode(INST_POP,					envPtr);
 	envPtr->currStackDepth = savedStackDepth + 1;
 	envPtr->line = bodyLines[i+1];		/* TIP #280 */
-	envPtr->clNext = bodyNext[i+1];		/* TIP #280 */
+	envPtr->clNext = bodyContLines[i+1];	/* TIP #280 */
 	TclCompileCmdWord(interp, bodyToken[i+1], 1, envPtr);
 
 	if (!foundDefault) {
 	    TclEmitForwardJump(envPtr, TCL_UNCONDITIONAL_JUMP,
-		    fixupArray+fixupCount);
+		    &fixupArray[fixupCount]);
 	    fixupCount++;
 	    fixupTargetArray[nextArmFixupIndex] = CurrentOffset(envPtr);
 	}
     }
 
     /*
-     * Clean up all our temporary space and return.
-     */
-
-    ckfree((char *) bodyToken);
-    ckfree((char *) bodyLines);
-    ckfree((char *) bodyNext);
-    if (bodyTokenArray != NULL) {
-	ckfree((char *) bodyTokenArray);
-    }
-
-    /*
      * Discard the value we are matching against unless we've had a default
      * clause (in which case it will already be gone due to the code at the
      * start of processing an arm, guaranteed) and make the result of the
@@ -4956,7 +4738,7 @@ TclCompileSwitchCmd(
      */
 
     if (!foundDefault) {
-	TclEmitOpcode(INST_POP, envPtr);
+	TclEmitOpcode(INST_POP,					envPtr);
 	PushLiteral(envPtr, "", 0);
     }
 
@@ -4991,11 +4773,208 @@ TclCompileSwitchCmd(
 	    }
 	}
     }
-    ckfree((char *) fixupArray);
-    ckfree((char *) fixupTargetArray);
+    TclStackFree(interp, fixupTargetArray);
+    TclStackFree(interp, fixupArray);
 
     envPtr->currStackDepth = savedStackDepth + 1;
-    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * IssueSwitchJumpTable --
+ *
+ *	Generate instructions for a [switch] command that is to be compiled
+ *	into a jump table. This only handles the case where case-sensitive,
+ *	exact matching is used, but this is actually the most common case in
+ *	real code.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+IssueSwitchJumpTable(
+    Tcl_Interp *interp,		/* Context for compiling script bodies. */
+    CompileEnv *envPtr,		/* Holds resulting instructions. */
+    ExtCmdLoc *mapPtr,		/* For mapping tokens to their source code
+				 * location. */
+    int eclIndex,
+    int valueIndex,		/* The value to match against. */
+    Tcl_Token *valueTokenPtr,
+    int numBodyTokens,		/* Number of tokens describing things the
+				 * switch can match against and bodies to
+				 * execute when the match succeeds. */
+    Tcl_Token **bodyToken,	/* Array of pointers to pattern list items. */
+    int *bodyLines,		/* Array of line numbers for body list
+				 * items. */
+    int **bodyContLines)	/* Array of continuation line info. */
+{
+    JumptableInfo *jtPtr;
+    int infoIndex, isNew, *finalFixups, numRealBodies = 0, jumpLocation;
+    int mustGenerate, foundDefault, jumpToDefault, i;
+    Tcl_DString buffer;
+    Tcl_HashEntry *hPtr;
+
+    /*
+     * First, we push the value we're matching against on the stack.
+     */
+
+    SetLineInformation(valueIndex);
+    CompileTokens(envPtr, valueTokenPtr, interp);
+
+    /*
+     * Compile the switch by using a jump table, which is basically a
+     * hashtable that maps from literal values to match against to the offset
+     * (relative to the INST_JUMP_TABLE instruction) to jump to. The jump
+     * table itself is independent of any invokation of the bytecode, and as
+     * such is stored in an auxData block.
+     *
+     * Start by allocating the jump table itself, plus some workspace.
+     */
+
+    jtPtr = (JumptableInfo *) ckalloc(sizeof(JumptableInfo));
+    Tcl_InitHashTable(&jtPtr->hashTable, TCL_STRING_KEYS);
+    infoIndex = TclCreateAuxData(jtPtr, &tclJumptableInfoType, envPtr);
+    finalFixups = TclStackAlloc(interp, sizeof(int) * (numBodyTokens/2));
+    foundDefault = 0;
+    mustGenerate = 1;
+
+    /*
+     * Next, issue the instruction to do the jump, together with what we want
+     * to do if things do not work out (jump to either the default clause or
+     * the "default" default, which just sets the result to empty). Note that
+     * we will come back and rewrite the jump's offset parameter when we know
+     * what it should be, and that all jumps we issue are of the wide kind
+     * because that makes the code much easier to debug!
+     */
+
+    jumpLocation = CurrentOffset(envPtr);
+    TclEmitInstInt4(INST_JUMP_TABLE, infoIndex,			envPtr);
+    jumpToDefault = CurrentOffset(envPtr);
+    TclEmitInstInt4(INST_JUMP4, 0,				envPtr);
+
+    for (i=0 ; i<numBodyTokens ; i+=2) {
+	/*
+	 * For each arm, we must first work out what to do with the match
+	 * term.
+	 */
+
+	if (i!=numBodyTokens-2 || bodyToken[numBodyTokens-2]->size != 7 ||
+		memcmp(bodyToken[numBodyTokens-2]->start, "default", 7)) {
+	    /*
+	     * This is not a default clause, so insert the current location as
+	     * a target in the jump table (assuming it isn't already there,
+	     * which would indicate that this clause is probably masked by an
+	     * earlier one). Note that we use a Tcl_DString here simply
+	     * because the hash API does not let us specify the string length.
+	     */
+
+	    Tcl_DStringInit(&buffer);
+	    Tcl_DStringAppend(&buffer, bodyToken[i]->start,
+		    bodyToken[i]->size);
+	    hPtr = Tcl_CreateHashEntry(&jtPtr->hashTable,
+		    Tcl_DStringValue(&buffer), &isNew);
+	    if (isNew) {
+		/*
+		 * First time we've encountered this match clause, so it must
+		 * point to here.
+		 */
+
+		Tcl_SetHashValue(hPtr, (ClientData)
+			(CurrentOffset(envPtr) - jumpLocation));
+	    }
+	    Tcl_DStringFree(&buffer);
+	} else {
+	    /*
+	     * This is a default clause, so patch up the fallthrough from the
+	     * INST_JUMP_TABLE instruction to here.
+	     */
+
+	    foundDefault = 1;
+	    isNew = 1;
+	    TclStoreInt4AtPtr(CurrentOffset(envPtr)-jumpToDefault,
+		    envPtr->codeStart+jumpToDefault+1);
+	}
+
+	/*
+	 * Now, for each arm we must deal with the body of the clause.
+	 *
+	 * If this is a continuation body (never true of a final clause,
+	 * whether default or not) we're done because the next jump target
+	 * will also point here, so we advance to the next clause.
+	 */
+
+	if (bodyToken[i+1]->size == 1 && bodyToken[i+1]->start[0] == '-') {
+	    mustGenerate = 1;
+	    continue;
+	}
+
+	/*
+	 * Also skip this arm if its only match clause is masked. (We could
+	 * probably be more aggressive about this, but that would be much more
+	 * difficult to get right.)
+	 */
+
+	if (!isNew && !mustGenerate) {
+	    continue;
+	}
+	mustGenerate = 0;
+
+	/*
+	 * Compile the body of the arm.
+	 */
+
+	envPtr->line = bodyLines[i+1];		/* TIP #280 */
+	envPtr->clNext = bodyContLines[i+1];	/* TIP #280 */
+	TclCompileCmdWord(interp, bodyToken[i+1], 1, envPtr);
+
+	/*
+	 * Compile a jump in to the end of the command if this body is
+	 * anything other than a user-supplied default arm (to either skip
+	 * over the remaining bodies or the code that generates an empty
+	 * result).
+	 */
+
+	if (i+2 < numBodyTokens || !foundDefault) {
+	    finalFixups[numRealBodies++] = CurrentOffset(envPtr);
+
+	    /*
+	     * Easier by far to issue this jump as a fixed-width jump, since
+	     * otherwise we'd need to do a lot more (and more awkward)
+	     * rewriting when we fixed this all up.
+	     */
+
+	    TclEmitInstInt4(INST_JUMP4, 0,			envPtr);
+	}
+    }
+
+    /*
+     * We're at the end. If we've not already done so through the processing
+     * of a user-supplied default clause, add in a "default" default clause
+     * now.
+     */
+
+    if (!foundDefault) {
+	TclStoreInt4AtPtr(CurrentOffset(envPtr)-jumpToDefault,
+		envPtr->codeStart+jumpToDefault+1);
+	PushLiteral(envPtr, "", 0);
+    }
+
+    /*
+     * No more instructions to be issued; everything that needs to jump to the
+     * end of the command is fixed up at this point.
+     */
+
+    for (i=0 ; i<numRealBodies ; i++) {
+	TclStoreInt4AtPtr(CurrentOffset(envPtr)-finalFixups[i],
+		envPtr->codeStart+finalFixups[i]+1);
+    }
+
+    /*
+     * Clean up all our temporary space and return.
+     */
+
+    TclStackFree(interp, finalFixups);
 }
 
 /*
@@ -7261,304 +7240,6 @@ TclCompileVariableCmd(
 /*
  *----------------------------------------------------------------------
  *
- * TclCompileEnsemble --
- *
- *	Procedure called to compile an ensemble command. Note that most
- *	ensembles are not compiled, since modifying a compiled ensemble causes
- *	a invalidation of all existing bytecode (expensive!) which is not
- *	normally warranted.
- *
- * 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 subcommands of the
- *	ensemble at runtime if a compile-time mapping is possible.
- *
- *----------------------------------------------------------------------
- */
-
-int
-TclCompileEnsemble(
-    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;
-    Tcl_Obj *mapObj, *subcmdObj, *targetCmdObj, *listObj, **elems;
-    Tcl_Command ensemble = (Tcl_Command) cmdPtr;
-    Tcl_Parse synthetic;
-    int len, numBytes, result, flags = 0, i;
-    const char *word;
-
-    if (parsePtr->numWords < 2) {
-	return TCL_ERROR;
-    }
-
-    tokenPtr = TokenAfter(parsePtr->tokenPtr);
-    if (tokenPtr->type != TCL_TOKEN_SIMPLE_WORD) {
-	/*
-	 * Too hard.
-	 */
-
-	return TCL_ERROR;
-    }
-
-    word = tokenPtr[1].start;
-    numBytes = tokenPtr[1].size;
-
-    /*
-     * There's a sporting chance we'll be able to compile this. But now we
-     * must check properly. To do that, check that we're compiling an ensemble
-     * that has a compilable command as its appropriate subcommand.
-     */
-
-    if (Tcl_GetEnsembleMappingDict(NULL, ensemble, &mapObj) != TCL_OK
-	    || mapObj == NULL) {
-	/*
-	 * Either not an ensemble or a mapping isn't installed. Crud. Too hard
-	 * to proceed.
-	 */
-
-	return TCL_ERROR;
-    }
-
-    /*
-     * Also refuse to compile anything that uses a formal parameter list for
-     * now, on the grounds that it is too complex.
-     */
-
-    if (Tcl_GetEnsembleParameterList(NULL, ensemble, &listObj) != TCL_OK
-	    || listObj != NULL) {
-	/*
-	 * Figuring out how to compile this has become too much. Bail out.
-	 */
-
-	return TCL_ERROR;
-    }
-
-    /*
-     * Next, get the flags. We need them on several code paths.
-     */
-
-    (void) Tcl_GetEnsembleFlags(NULL, ensemble, &flags);
-
-    /*
-     * Check to see if there's also a subcommand list; must check to see if
-     * the subcommand we are calling is in that list if it exists, since that
-     * list filters the entries in the map.
-     */
-
-    (void) Tcl_GetEnsembleSubcommandList(NULL, ensemble, &listObj);
-    if (listObj != NULL) {
-	int sclen;
-	const char *str;
-	Tcl_Obj *matchObj = NULL;
-
-	if (Tcl_ListObjGetElements(NULL, listObj, &len, &elems) != TCL_OK) {
-	    return TCL_ERROR;
-	}
-	for (i=0 ; i<len ; i++) {
-	    str = Tcl_GetStringFromObj(elems[i], &sclen);
-	    if (sclen==numBytes && !memcmp(word, str, (unsigned) numBytes)) {
-		/*
-		 * Exact match! Excellent!
-		 */
-
-		result = Tcl_DictObjGet(NULL, mapObj,elems[i], &targetCmdObj);
-		if (result != TCL_OK || targetCmdObj == NULL) {
-		    return TCL_ERROR;
-		}
-		goto doneMapLookup;
-	    }
-
-	    /*
-	     * Check to see if we've got a prefix match. A single prefix match
-	     * is fine, and allows us to refine our dictionary lookup, but
-	     * multiple prefix matches is a Bad Thing and will prevent us from
-	     * making progress. Note that we cannot do the lookup immediately
-	     * in the prefix case; might be another entry later in the list
-	     * that causes things to fail.
-	     */
-
-	    if ((flags & TCL_ENSEMBLE_PREFIX)
-		    && strncmp(word, str, (unsigned) numBytes) == 0) {
-		if (matchObj != NULL) {
-		    return TCL_ERROR;
-		}
-		matchObj = elems[i];
-	    }
-	}
-	if (matchObj != NULL) {
-	    result = Tcl_DictObjGet(NULL, mapObj, matchObj, &targetCmdObj);
-	    if (result != TCL_OK || targetCmdObj == NULL) {
-		return TCL_ERROR;
-	    }
-	    goto doneMapLookup;
-	}
-	return TCL_ERROR;
-    } else {
-	/*
-	 * No map, so check the dictionary directly.
-	 */
-
-	TclNewStringObj(subcmdObj, word, numBytes);
-	result = Tcl_DictObjGet(NULL, mapObj, subcmdObj, &targetCmdObj);
-	TclDecrRefCount(subcmdObj);
-	if (result == TCL_OK && targetCmdObj != NULL) {
-	    /*
-	     * Got it. Skip the fiddling around with prefixes.
-	     */
-
-	    goto doneMapLookup;
-	}
-
-	/*
-	 * We've not literally got a valid subcommand. But maybe we have a
-	 * prefix. Check if prefix matches are allowed.
-	 */
-
-	if (flags & TCL_ENSEMBLE_PREFIX) {
-	    Tcl_DictSearch s;
-	    int done, matched;
-	    Tcl_Obj *tmpObj;
-
-	    /*
-	     * Iterate over the keys in the dictionary, checking to see if
-	     * we're a prefix.
-	     */
-
-	    Tcl_DictObjFirst(NULL,mapObj,&s,&subcmdObj,&tmpObj,&done);
-	    matched = 0;
-	    while (!done) {
-		if (strncmp(TclGetString(subcmdObj), word,
-			(unsigned) numBytes) == 0) {
-		    if (matched++) {
-			/*
-			 * Must have matched twice! Not unique, so no point
-			 * looking further.
-			 */
-
-			break;
-		    }
-		    targetCmdObj = tmpObj;
-		}
-		Tcl_DictObjNext(&s, &subcmdObj, &tmpObj, &done);
-	    }
-	    Tcl_DictObjDone(&s);
-
-	    /*
-	     * If we have anything other than a single match, we've failed the
-	     * unique prefix check.
-	     */
-
-	    if (matched != 1) {
-		return TCL_ERROR;
-	    }
-	} else {
-	    return TCL_ERROR;
-	}
-    }
-
-    /*
-     * OK, we definitely map to something. But what?
-     *
-     * The command we map to is the first word out of the map element. Note
-     * that we also reject dealing with multi-element rewrites if we are in a
-     * safe interpreter, as there is otherwise a (highly gnarly!) way to make
-     * Tcl crash open to exploit.
-     */
-
-  doneMapLookup:
-    if (Tcl_ListObjGetElements(NULL, targetCmdObj, &len, &elems) != TCL_OK) {
-	return TCL_ERROR;
-    }
-    if (len > 1 && Tcl_IsSafe(interp)) {
-	return TCL_ERROR;
-    }
-    targetCmdObj = elems[0];
-
-    Tcl_IncrRefCount(targetCmdObj);
-    cmdPtr = (Command *) Tcl_GetCommandFromObj(interp, targetCmdObj);
-    TclDecrRefCount(targetCmdObj);
-    if (cmdPtr == NULL || cmdPtr->compileProc == NULL) {
-	/*
-	 * Maps to an undefined command or a command without a compiler.
-	 * Cannot compile.
-	 */
-
-	return TCL_ERROR;
-    }
-
-    /*
-     * Now we've done the mapping process, can now actually try to compile.
-     * We do this by handing off to the subcommand's actual compiler. But to
-     * do that, we have to perform some trickery to rewrite the arguments.
-     */
-
-    TclParseInit(interp, NULL, 0, &synthetic);
-    synthetic.numWords = parsePtr->numWords - 2 + len;
-    TclGrowParseTokenArray(&synthetic, 2*len);
-    synthetic.numTokens = 2*len;
-
-    /*
-     * Now we have the space to work in, install something rewritten. Note
-     * that we are here praying for all our might that none of these words are
-     * a script; the error detection code will crash if that happens and there
-     * is nothing we can do to avoid it!
-     */
-
-    for (i=0 ; i<len ; i++) {
-	int sclen;
-	const char *str = Tcl_GetStringFromObj(elems[i], &sclen);
-
-	synthetic.tokenPtr[2*i].type = TCL_TOKEN_SIMPLE_WORD;
-	synthetic.tokenPtr[2*i].start = str;
-	synthetic.tokenPtr[2*i].size = sclen;
-	synthetic.tokenPtr[2*i].numComponents = 1;
-
-	synthetic.tokenPtr[2*i+1].type = TCL_TOKEN_TEXT;
-	synthetic.tokenPtr[2*i+1].start = str;
-	synthetic.tokenPtr[2*i+1].size = sclen;
-	synthetic.tokenPtr[2*i+1].numComponents = 0;
-    }
-
-    /*
-     * Copy over the real argument tokens.
-     */
-
-    for (i=len; i<synthetic.numWords; i++) {
-	int toCopy;
-
-	tokenPtr = TokenAfter(tokenPtr);
-	toCopy = tokenPtr->numComponents + 1;
-	TclGrowParseTokenArray(&synthetic, toCopy);
-	memcpy(synthetic.tokenPtr + synthetic.numTokens, tokenPtr,
-		sizeof(Tcl_Token) * toCopy);
-	synthetic.numTokens += toCopy;
-    }
-
-    /*
-     * Hand off compilation to the subcommand compiler. At last!
-     */
-
-    result = cmdPtr->compileProc(interp, &synthetic, cmdPtr, envPtr);
-
-    /*
-     * Clean up if necessary.
-     */
-
-    Tcl_FreeParse(&synthetic);
-    return result;
-}
-
-/*
- *----------------------------------------------------------------------
- *
  * TclCompileInfoExistsCmd --
  *
  *	Procedure called to compile the "info exists" subcommand.
diff --git a/generic/tclCompile.h b/generic/tclCompile.h
index 18dad76..b9b93cb 100644
--- a/generic/tclCompile.h
+++ b/generic/tclCompile.h
@@ -9,7 +9,7 @@
  * See the file "license.terms" for information on usage and redistribution of
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclCompile.h,v 1.122 2010/01/30 16:33:25 dkf Exp $
+ * RCS: @(#) $Id: tclCompile.h,v 1.123 2010/02/13 18:11:06 dkf Exp $
  */
 
 #ifndef _TCLCOMPILATION
@@ -1252,6 +1252,94 @@ MODULE_SCOPE int	TclWordKnownAtCompileTime(Tcl_Token *tokenPtr,
 #define TclMax(i, j)   ((((int) i) > ((int) j))? (i) : (j))
 
 /*
+ * Convenience macro for use when compiling bodies of commands. The ANSI C
+ * "prototype" for this macro is:
+ *
+ * static void		CompileBody(CompileEnv *envPtr, Tcl_Token *tokenPtr,
+ *			    Tcl_Interp *interp);
+ */
+
+#define CompileBody(envPtr, tokenPtr, interp) \
+    TclCompileCmdWord((interp), (tokenPtr)+1, (tokenPtr)->numComponents, \
+	    (envPtr))
+
+/*
+ * Convenience macro for use when compiling tokens to be pushed. The ANSI C
+ * "prototype" for this macro is:
+ *
+ * static void		CompileTokens(CompileEnv *envPtr, Tcl_Token *tokenPtr,
+ *			    Tcl_Interp *interp);
+ */
+
+#define CompileTokens(envPtr, tokenPtr, interp) \
+    TclCompileTokens((interp), (tokenPtr)+1, (tokenPtr)->numComponents, \
+	    (envPtr));
+/*
+ * Convenience macro for use when pushing literals. The ANSI C "prototype" for
+ * this macro is:
+ *
+ * static void		PushLiteral(CompileEnv *envPtr,
+ *			    const char *string, int length);
+ */
+
+#define PushLiteral(envPtr, string, length) \
+    TclEmitPush(TclRegisterNewLiteral((envPtr), (string), (length)), (envPtr))
+
+/*
+ * Macro to advance to the next token; it is more mnemonic than the address
+ * arithmetic that it replaces. The ANSI C "prototype" for this macro is:
+ *
+ * static Tcl_Token *	TokenAfter(Tcl_Token *tokenPtr);
+ */
+
+#define TokenAfter(tokenPtr) \
+    ((tokenPtr) + ((tokenPtr)->numComponents + 1))
+
+/*
+ * Macro to get the offset to the next instruction to be issued. The ANSI C
+ * "prototype" for this macro is:
+ *
+ * static int	CurrentOffset(CompileEnv *envPtr);
+ */
+
+#define CurrentOffset(envPtr) \
+    ((envPtr)->codeNext - (envPtr)->codeStart)
+
+/*
+ * Note: the exceptDepth is a bit of a misnomer: TEBC only needs the
+ * maximal depth of nested CATCH ranges in order to alloc runtime
+ * memory. These macros should compute precisely that? OTOH, the nesting depth
+ * of LOOP ranges is an interesting datum for debugging purposes, and that is
+ * what we compute now.
+ *
+ * static int	DeclareExceptionRange(CompileEnv *envPtr, int type);
+ * static int	ExceptionRangeStarts(CompileEnv *envPtr, int index);
+ * static void	ExceptionRangeEnds(CompileEnv *envPtr, int index);
+ * static void	ExceptionRangeTarget(CompileEnv *envPtr, int index, LABEL);
+ */
+
+#define DeclareExceptionRange(envPtr, type) \
+    (TclCreateExceptRange((type), (envPtr)))
+#define ExceptionRangeStarts(envPtr, index) \
+    (((envPtr)->exceptDepth++),						\
+    ((envPtr)->maxExceptDepth =						\
+	    TclMax((envPtr)->exceptDepth, (envPtr)->maxExceptDepth)),	\
+    ((envPtr)->exceptArrayPtr[(index)].codeOffset = CurrentOffset(envPtr)))
+#define ExceptionRangeEnds(envPtr, index) \
+    (((envPtr)->exceptDepth--),						\
+    ((envPtr)->exceptArrayPtr[(index)].numCodeBytes =			\
+	CurrentOffset(envPtr) - (envPtr)->exceptArrayPtr[(index)].codeOffset))
+#define ExceptionRangeTarget(envPtr, index, targetType) \
+    ((envPtr)->exceptArrayPtr[(index)].targetType = CurrentOffset(envPtr))
+
+/*
+ * Check if there is an LVT for compiled locals
+ */
+
+#define EnvHasLVT(envPtr) \
+    (envPtr->procPtr || envPtr->iPtr->varFramePtr->localCachePtr)
+
+/*
  * DTrace probe macros (NOPs if DTrace support is not enabled).
  */
 
diff --git a/generic/tclEnsemble.c b/generic/tclEnsemble.c
new file mode 100644
index 0000000..4dd86b7
--- /dev/null
+++ b/generic/tclEnsemble.c
@@ -0,0 +1,2965 @@
+/*
+ * tclEnsemble.c --
+ *
+ *	Contains support for ensembles, which provide simple mechanism
+ *	for creating composite commands on top of namespaces.
+ *
+ * Copyright (c) 2005-2010 Donal K. Fellows.
+ *
+ * See the file "license.terms" for information on usage and redistribution of
+ * this file, and for a DISCLAIMER OF ALL WARRANTIES.
+ *
+ * RCS: @(#) $Id: tclEnsemble.c,v 1.1 2010/02/13 18:11:06 dkf Exp $
+ */
+
+#include "tclInt.h"
+#include "tclCompile.h"
+
+/*
+ * Declarations for functions local to this file:
+ */
+
+static inline int	EnsembleUnknownCallback(Tcl_Interp *interp,
+			    EnsembleConfig *ensemblePtr, int objc,
+			    Tcl_Obj *const objv[], Tcl_Obj **prefixObjPtr);
+static int		NsEnsembleImplementationCmd(ClientData clientData,
+			    Tcl_Interp *interp,int objc,Tcl_Obj *const objv[]);
+static int		NsEnsembleImplementationCmdNR(ClientData clientData,
+			    Tcl_Interp *interp,int objc,Tcl_Obj *const objv[]);
+static void		BuildEnsembleConfig(EnsembleConfig *ensemblePtr);
+static int		NsEnsembleStringOrder(const void *strPtr1,
+			    const void *strPtr2);
+static void		DeleteEnsembleConfig(ClientData clientData);
+static void		MakeCachedEnsembleCommand(Tcl_Obj *objPtr,
+			    EnsembleConfig *ensemblePtr,
+			    const char *subcmdName, Tcl_Obj *prefixObjPtr);
+static void		FreeEnsembleCmdRep(Tcl_Obj *objPtr);
+static void		DupEnsembleCmdRep(Tcl_Obj *objPtr, Tcl_Obj *copyPtr);
+static void		StringOfEnsembleCmdRep(Tcl_Obj *objPtr);
+
+/*
+ * This structure defines a Tcl object type that contains a reference to an
+ * ensemble subcommand (e.g. the "length" in [string length ab]). It is used
+ * to cache the mapping between the subcommand itself and the real command
+ * that implements it.
+ */
+
+const Tcl_ObjType tclEnsembleCmdType = {
+    "ensembleCommand",		/* the type's name */
+    FreeEnsembleCmdRep,		/* freeIntRepProc */
+    DupEnsembleCmdRep,		/* dupIntRepProc */
+    StringOfEnsembleCmdRep,	/* updateStringProc */
+    NULL			/* setFromAnyProc */
+};
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclNamespaceEnsembleCmd --
+ *
+ *	Invoked to implement the "namespace ensemble" command that creates and
+ *	manipulates ensembles built on top of namespaces. Handles the
+ *	following syntax:
+ *
+ *	    namespace ensemble name ?dictionary?
+ *
+ * Results:
+ *	Returns TCL_OK if successful, and TCL_ERROR if anything goes wrong.
+ *
+ * Side effects:
+ *	Creates the ensemble for the namespace if one did not previously
+ *	exist. Alternatively, alters the way that the ensemble's subcommand =>
+ *	implementation prefix is configured.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+TclNamespaceEnsembleCmd(
+    ClientData dummy,
+    Tcl_Interp *interp,
+    int objc,
+    Tcl_Obj *const objv[])
+{
+    Namespace *nsPtr;
+    Tcl_Command token;
+    static const char *const subcommands[] = {
+	"configure", "create", "exists", NULL
+    };
+    enum EnsSubcmds {
+	ENS_CONFIG, ENS_CREATE, ENS_EXISTS
+    };
+    static const char *const createOptions[] = {
+	"-command", "-map", "-parameters", "-prefixes", "-subcommands",
+	"-unknown", NULL
+    };
+    enum EnsCreateOpts {
+	CRT_CMD, CRT_MAP, CRT_PARAM, CRT_PREFIX, CRT_SUBCMDS, CRT_UNKNOWN
+    };
+    static const char *const configOptions[] = {
+	"-map", "-namespace", "-parameters", "-prefixes", "-subcommands",
+	"-unknown", NULL
+    };
+    enum EnsConfigOpts {
+	CONF_MAP, CONF_NAMESPACE, CONF_PARAM, CONF_PREFIX, CONF_SUBCMDS,
+	CONF_UNKNOWN
+    };
+    int index;
+
+    nsPtr = (Namespace *) TclGetCurrentNamespace(interp);
+    if (nsPtr == NULL || nsPtr->flags & NS_DYING) {
+	if (!Tcl_InterpDeleted(interp)) {
+	    Tcl_AppendResult(interp,
+		    "tried to manipulate ensemble of deleted namespace", NULL);
+	}
+	return TCL_ERROR;
+    }
+
+    if (objc < 3) {
+	Tcl_WrongNumArgs(interp, 2, objv, "subcommand ?arg ...?");
+	return TCL_ERROR;
+    }
+    if (Tcl_GetIndexFromObj(interp, objv[2], subcommands, "subcommand", 0,
+	    &index) != TCL_OK) {
+	return TCL_ERROR;
+    }
+
+    switch ((enum EnsSubcmds) index) {
+    case ENS_CREATE: {
+	const char *name;
+	Tcl_DictSearch search;
+	Tcl_Obj *listObj;
+	int done, len, allocatedMapFlag = 0;
+	/*
+	 * Defaults
+	 */
+	Tcl_Obj *subcmdObj = NULL;
+	Tcl_Obj *mapObj = NULL;
+	int permitPrefix = 1;
+	Tcl_Obj *unknownObj = NULL;
+	Tcl_Obj *paramObj = NULL;
+
+	/*
+	 * Check that we've got option-value pairs... [Bug 1558654]
+	 */
+
+	if ((objc & 1) == 0) {
+	    Tcl_WrongNumArgs(interp, 3, objv, "?option value ...?");
+	    return TCL_ERROR;
+	}
+	objv += 3;
+	objc -= 3;
+
+	/*
+	 * Work out what name to use for the command to create. If supplied,
+	 * it is either fully specified or relative to the current namespace.
+	 * If not supplied, it is exactly the name of the current namespace.
+	 */
+
+	name = nsPtr->fullName;
+
+	/*
+	 * Parse the option list, applying type checks as we go. Note that we
+	 * are not incrementing any reference counts in the objects at this
+	 * stage, so the presence of an option multiple times won't cause any
+	 * memory leaks.
+	 */
+
+	for (; objc>1 ; objc-=2,objv+=2) {
+	    if (Tcl_GetIndexFromObj(interp, objv[0], createOptions, "option",
+		    0, &index) != TCL_OK) {
+		if (allocatedMapFlag) {
+		    Tcl_DecrRefCount(mapObj);
+		}
+		return TCL_ERROR;
+	    }
+	    switch ((enum EnsCreateOpts) index) {
+	    case CRT_CMD:
+		name = TclGetString(objv[1]);
+		continue;
+	    case CRT_SUBCMDS:
+		if (TclListObjLength(interp, objv[1], &len) != TCL_OK) {
+		    if (allocatedMapFlag) {
+			Tcl_DecrRefCount(mapObj);
+		    }
+		    return TCL_ERROR;
+		}
+		subcmdObj = (len > 0 ? objv[1] : NULL);
+		continue;
+	    case CRT_PARAM:
+		if (TclListObjLength(interp, objv[1], &len) != TCL_OK) {
+		    if (allocatedMapFlag) {
+			Tcl_DecrRefCount(mapObj);
+		    }
+		    return TCL_ERROR;
+		}
+		paramObj = (len > 0 ? objv[1] : NULL);
+		continue;
+	    case CRT_MAP: {
+		Tcl_Obj *patchedDict = NULL, *subcmdObj;
+
+		/*
+		 * Verify that the map is sensible.
+		 */
+
+		if (Tcl_DictObjFirst(interp, objv[1], &search,
+			&subcmdObj, &listObj, &done) != TCL_OK) {
+		    if (allocatedMapFlag) {
+			Tcl_DecrRefCount(mapObj);
+		    }
+		    return TCL_ERROR;
+		}
+		if (done) {
+		    mapObj = NULL;
+		    continue;
+		}
+		do {
+		    Tcl_Obj **listv;
+		    const char *cmd;
+
+		    if (TclListObjGetElements(interp, listObj, &len,
+			    &listv) != TCL_OK) {
+			Tcl_DictObjDone(&search);
+			if (patchedDict) {
+			    Tcl_DecrRefCount(patchedDict);
+			}
+			if (allocatedMapFlag) {
+			    Tcl_DecrRefCount(mapObj);
+			}
+			return TCL_ERROR;
+		    }
+		    if (len < 1) {
+			Tcl_SetResult(interp,
+				"ensemble subcommand implementations "
+				"must be non-empty lists", TCL_STATIC);
+			Tcl_DictObjDone(&search);
+			if (patchedDict) {
+			    Tcl_DecrRefCount(patchedDict);
+			}
+			if (allocatedMapFlag) {
+			    Tcl_DecrRefCount(mapObj);
+			}
+			return TCL_ERROR;
+		    }
+		    cmd = TclGetString(listv[0]);
+		    if (!(cmd[0] == ':' && cmd[1] == ':')) {
+			Tcl_Obj *newList = Tcl_NewListObj(len, listv);
+			Tcl_Obj *newCmd = Tcl_NewStringObj(nsPtr->fullName,-1);
+
+			if (nsPtr->parentPtr) {
+			    Tcl_AppendStringsToObj(newCmd, "::", NULL);
+			}
+			Tcl_AppendObjToObj(newCmd, listv[0]);
+			Tcl_ListObjReplace(NULL, newList, 0, 1, 1, &newCmd);
+			if (patchedDict == NULL) {
+			    patchedDict = Tcl_DuplicateObj(objv[1]);
+			}
+			Tcl_DictObjPut(NULL, patchedDict, subcmdObj, newList);
+		    }
+		    Tcl_DictObjNext(&search, &subcmdObj, &listObj, &done);
+		} while (!done);
+
+		if (allocatedMapFlag) {
+		    Tcl_DecrRefCount(mapObj);
+		}
+		mapObj = (patchedDict ? patchedDict : objv[1]);
+		if (patchedDict) {
+		    allocatedMapFlag = 1;
+		}
+		continue;
+	    }
+	    case CRT_PREFIX:
+		if (Tcl_GetBooleanFromObj(interp, objv[1],
+			&permitPrefix) != TCL_OK) {
+		    if (allocatedMapFlag) {
+			Tcl_DecrRefCount(mapObj);
+		    }
+		    return TCL_ERROR;
+		}
+		continue;
+	    case CRT_UNKNOWN:
+		if (TclListObjLength(interp, objv[1], &len) != TCL_OK) {
+		    if (allocatedMapFlag) {
+			Tcl_DecrRefCount(mapObj);
+		    }
+		    return TCL_ERROR;
+		}
+		unknownObj = (len > 0 ? objv[1] : NULL);
+		continue;
+	    }
+	}
+
+	/*
+	 * Create the ensemble. Note that this might delete another ensemble
+	 * linked to the same namespace, so we must be careful. However, we
+	 * should be OK because we only link the namespace into the list once
+	 * we've created it (and after any deletions have occurred.)
+	 */
+
+	token = Tcl_CreateEnsemble(interp, name, NULL,
+		(permitPrefix ? TCL_ENSEMBLE_PREFIX : 0));
+	Tcl_SetEnsembleSubcommandList(interp, token, subcmdObj);
+	Tcl_SetEnsembleMappingDict(interp, token, mapObj);
+	Tcl_SetEnsembleUnknownHandler(interp, token, unknownObj);
+	Tcl_SetEnsembleParameterList(interp, token, paramObj);
+
+	/*
+	 * Tricky! Must ensure that the result is not shared (command delete
+	 * traces could have corrupted the pristine object that we started
+	 * with). [Snit test rename-1.5]
+	 */
+
+	Tcl_ResetResult(interp);
+	Tcl_GetCommandFullName(interp, token, Tcl_GetObjResult(interp));
+	return TCL_OK;
+    }
+
+    case ENS_EXISTS:
+	if (objc != 4) {
+	    Tcl_WrongNumArgs(interp, 3, objv, "cmdname");
+	    return TCL_ERROR;
+	}
+	Tcl_SetObjResult(interp, Tcl_NewBooleanObj(
+		Tcl_FindEnsemble(interp, objv[3], 0) != NULL));
+	return TCL_OK;
+
+    case ENS_CONFIG:
+	if (objc < 4 || (objc != 5 && objc & 1)) {
+	    Tcl_WrongNumArgs(interp, 3, objv,
+		    "cmdname ?-option value ...? ?arg ...?");
+	    return TCL_ERROR;
+	}
+	token = Tcl_FindEnsemble(interp, objv[3], TCL_LEAVE_ERR_MSG);
+	if (token == NULL) {
+	    return TCL_ERROR;
+	}
+
+	if (objc == 5) {
+	    Tcl_Obj *resultObj = NULL;		/* silence gcc 4 warning */
+
+	    if (Tcl_GetIndexFromObj(interp, objv[4], configOptions, "option",
+		    0, &index) != TCL_OK) {
+		return TCL_ERROR;
+	    }
+	    switch ((enum EnsConfigOpts) index) {
+	    case CONF_SUBCMDS:
+		Tcl_GetEnsembleSubcommandList(NULL, token, &resultObj);
+		if (resultObj != NULL) {
+		    Tcl_SetObjResult(interp, resultObj);
+		}
+		break;
+	    case CONF_PARAM:
+		Tcl_GetEnsembleParameterList(NULL, token, &resultObj);
+		if (resultObj != NULL) {
+		    Tcl_SetObjResult(interp, resultObj);
+		}
+		break;
+	    case CONF_MAP:
+		Tcl_GetEnsembleMappingDict(NULL, token, &resultObj);
+		if (resultObj != NULL) {
+		    Tcl_SetObjResult(interp, resultObj);
+		}
+		break;
+	    case CONF_NAMESPACE: {
+		Tcl_Namespace *namespacePtr = NULL; /* silence gcc 4 warning */
+
+		Tcl_GetEnsembleNamespace(NULL, token, &namespacePtr);
+		Tcl_SetResult(interp, ((Namespace *) namespacePtr)->fullName,
+			TCL_VOLATILE);
+		break;
+	    }
+	    case CONF_PREFIX: {
+		int flags = 0;			/* silence gcc 4 warning */
+
+		Tcl_GetEnsembleFlags(NULL, token, &flags);
+		Tcl_SetObjResult(interp,
+			Tcl_NewBooleanObj(flags & TCL_ENSEMBLE_PREFIX));
+		break;
+	    }
+	    case CONF_UNKNOWN:
+		Tcl_GetEnsembleUnknownHandler(NULL, token, &resultObj);
+		if (resultObj != NULL) {
+		    Tcl_SetObjResult(interp, resultObj);
+		}
+		break;
+	    }
+	    return TCL_OK;
+
+	} else if (objc == 4) {
+	    /*
+	     * Produce list of all information.
+	     */
+
+	    Tcl_Obj *resultObj, *tmpObj = NULL;	/* silence gcc 4 warning */
+	    Tcl_Namespace *namespacePtr = NULL;	/* silence gcc 4 warning */
+	    int flags = 0;			/* silence gcc 4 warning */
+
+	    TclNewObj(resultObj);
+
+	    /* -map option */
+	    Tcl_ListObjAppendElement(NULL, resultObj,
+		    Tcl_NewStringObj(configOptions[CONF_MAP], -1));
+	    Tcl_GetEnsembleMappingDict(NULL, token, &tmpObj);
+	    Tcl_ListObjAppendElement(NULL, resultObj,
+		    (tmpObj != NULL) ? tmpObj : Tcl_NewObj());
+
+	    /* -namespace option */
+	    Tcl_ListObjAppendElement(NULL, resultObj,
+		    Tcl_NewStringObj(configOptions[CONF_NAMESPACE], -1));
+	    Tcl_GetEnsembleNamespace(NULL, token, &namespacePtr);
+	    Tcl_ListObjAppendElement(NULL, resultObj,
+		    Tcl_NewStringObj(((Namespace *) namespacePtr)->fullName,
+		    -1));
+
+	    /* -parameters option */
+	    Tcl_ListObjAppendElement(NULL, resultObj,
+		    Tcl_NewStringObj(configOptions[CONF_PARAM], -1));
+	    Tcl_GetEnsembleParameterList(NULL, token, &tmpObj);
+	    Tcl_ListObjAppendElement(NULL, resultObj,
+		    (tmpObj != NULL) ? tmpObj : Tcl_NewObj());
+
+	    /* -prefix option */
+	    Tcl_ListObjAppendElement(NULL, resultObj,
+		    Tcl_NewStringObj(configOptions[CONF_PREFIX], -1));
+	    Tcl_GetEnsembleFlags(NULL, token, &flags);
+	    Tcl_ListObjAppendElement(NULL, resultObj,
+		    Tcl_NewBooleanObj(flags & TCL_ENSEMBLE_PREFIX));
+
+	    /* -subcommands option */
+	    Tcl_ListObjAppendElement(NULL, resultObj,
+		    Tcl_NewStringObj(configOptions[CONF_SUBCMDS], -1));
+	    Tcl_GetEnsembleSubcommandList(NULL, token, &tmpObj);
+	    Tcl_ListObjAppendElement(NULL, resultObj,
+		    (tmpObj != NULL) ? tmpObj : Tcl_NewObj());
+
+	    /* -unknown option */
+	    Tcl_ListObjAppendElement(NULL, resultObj,
+		    Tcl_NewStringObj(configOptions[CONF_UNKNOWN], -1));
+	    Tcl_GetEnsembleUnknownHandler(NULL, token, &tmpObj);
+	    Tcl_ListObjAppendElement(NULL, resultObj,
+		    (tmpObj != NULL) ? tmpObj : Tcl_NewObj());
+
+	    Tcl_SetObjResult(interp, resultObj);
+	    return TCL_OK;
+	} else {
+	    Tcl_DictSearch search;
+	    Tcl_Obj *listObj;
+	    int done, len, allocatedMapFlag = 0;
+	    Tcl_Obj *subcmdObj = NULL, *mapObj = NULL, *paramObj = NULL,
+		    *unknownObj = NULL; /* Defaults, silence gcc 4 warnings */
+	    int permitPrefix, flags = 0;	/* silence gcc 4 warning */
+
+	    Tcl_GetEnsembleSubcommandList(NULL, token, &subcmdObj);
+	    Tcl_GetEnsembleMappingDict(NULL, token, &mapObj);
+	    Tcl_GetEnsembleParameterList(NULL, token, &paramObj);
+	    Tcl_GetEnsembleUnknownHandler(NULL, token, &unknownObj);
+	    Tcl_GetEnsembleFlags(NULL, token, &flags);
+	    permitPrefix = (flags & TCL_ENSEMBLE_PREFIX) != 0;
+
+	    objv += 4;
+	    objc -= 4;
+
+	    /*
+	     * Parse the option list, applying type checks as we go. Note that
+	     * we are not incrementing any reference counts in the objects at
+	     * this stage, so the presence of an option multiple times won't
+	     * cause any memory leaks.
+	     */
+
+	    for (; objc>0 ; objc-=2,objv+=2) {
+		if (Tcl_GetIndexFromObj(interp, objv[0], configOptions,
+			"option", 0, &index) != TCL_OK) {
+		    if (allocatedMapFlag) {
+			Tcl_DecrRefCount(mapObj);
+		    }
+		    return TCL_ERROR;
+		}
+		switch ((enum EnsConfigOpts) index) {
+		case CONF_SUBCMDS:
+		    if (TclListObjLength(interp, objv[1], &len) != TCL_OK) {
+			if (allocatedMapFlag) {
+			    Tcl_DecrRefCount(mapObj);
+			}
+			return TCL_ERROR;
+		    }
+		    subcmdObj = (len > 0 ? objv[1] : NULL);
+		    continue;
+		case CONF_PARAM:
+		    if (TclListObjLength(interp, objv[1], &len) != TCL_OK) {
+			if (allocatedMapFlag) {
+			    Tcl_DecrRefCount(mapObj);
+			}
+			return TCL_ERROR;
+		    }
+		    paramObj = (len > 0 ? objv[1] : NULL);
+		    continue;
+		case CONF_MAP: {
+		    Tcl_Obj *patchedDict = NULL, *subcmdObj;
+
+		    /*
+		     * Verify that the map is sensible.
+		     */
+
+		    if (Tcl_DictObjFirst(interp, objv[1], &search,
+			    &subcmdObj, &listObj, &done) != TCL_OK) {
+			if (allocatedMapFlag) {
+			    Tcl_DecrRefCount(mapObj);
+			}
+			return TCL_ERROR;
+		    }
+		    if (done) {
+			mapObj = NULL;
+			continue;
+		    }
+		    do {
+			Tcl_Obj **listv;
+			const char *cmd;
+
+			if (TclListObjGetElements(interp, listObj, &len,
+				&listv) != TCL_OK) {
+			    Tcl_DictObjDone(&search);
+			    if (patchedDict) {
+				Tcl_DecrRefCount(patchedDict);
+			    }
+			    if (allocatedMapFlag) {
+				Tcl_DecrRefCount(mapObj);
+			    }
+			    return TCL_ERROR;
+			}
+			if (len < 1) {
+			    Tcl_SetResult(interp,
+				    "ensemble subcommand implementations "
+				    "must be non-empty lists", TCL_STATIC);
+			    Tcl_DictObjDone(&search);
+			    if (patchedDict) {
+				Tcl_DecrRefCount(patchedDict);
+			    }
+			    if (allocatedMapFlag) {
+				Tcl_DecrRefCount(mapObj);
+			    }
+			    return TCL_ERROR;
+			}
+			cmd = TclGetString(listv[0]);
+			if (!(cmd[0] == ':' && cmd[1] == ':')) {
+			    Tcl_Obj *newList = Tcl_NewListObj(len, listv);
+			    Tcl_Obj *newCmd =
+				    Tcl_NewStringObj(nsPtr->fullName, -1);
+
+			    if (nsPtr->parentPtr) {
+				Tcl_AppendStringsToObj(newCmd, "::", NULL);
+			    }
+			    Tcl_AppendObjToObj(newCmd, listv[0]);
+			    Tcl_ListObjReplace(NULL, newList, 0,1, 1,&newCmd);
+			    if (patchedDict == NULL) {
+				patchedDict = Tcl_DuplicateObj(objv[1]);
+			    }
+			    Tcl_DictObjPut(NULL, patchedDict, subcmdObj,
+				    newList);
+			}
+			Tcl_DictObjNext(&search, &subcmdObj, &listObj, &done);
+		    } while (!done);
+		    if (allocatedMapFlag) {
+			Tcl_DecrRefCount(mapObj);
+		    }
+		    mapObj = (patchedDict ? patchedDict : objv[1]);
+		    if (patchedDict) {
+			allocatedMapFlag = 1;
+		    }
+		    continue;
+		}
+		case CONF_NAMESPACE:
+		    if (allocatedMapFlag) {
+			Tcl_DecrRefCount(mapObj);
+		    }
+		    Tcl_AppendResult(interp, "option -namespace is read-only",
+			    NULL);
+		    return TCL_ERROR;
+		case CONF_PREFIX:
+		    if (Tcl_GetBooleanFromObj(interp, objv[1],
+			    &permitPrefix) != TCL_OK) {
+			if (allocatedMapFlag) {
+			    Tcl_DecrRefCount(mapObj);
+			}
+			return TCL_ERROR;
+		    }
+		    continue;
+		case CONF_UNKNOWN:
+		    if (TclListObjLength(interp, objv[1], &len) != TCL_OK) {
+			if (allocatedMapFlag) {
+			    Tcl_DecrRefCount(mapObj);
+			}
+			return TCL_ERROR;
+		    }
+		    unknownObj = (len > 0 ? objv[1] : NULL);
+		    continue;
+		}
+	    }
+
+	    /*
+	     * Update the namespace now that we've finished the parsing stage.
+	     */
+
+	    flags = (permitPrefix ? flags|TCL_ENSEMBLE_PREFIX
+		    : flags&~TCL_ENSEMBLE_PREFIX);
+	    Tcl_SetEnsembleSubcommandList(interp, token, subcmdObj);
+	    Tcl_SetEnsembleMappingDict(interp, token, mapObj);
+	    Tcl_SetEnsembleParameterList(interp, token, paramObj);
+	    Tcl_SetEnsembleUnknownHandler(interp, token, unknownObj);
+	    Tcl_SetEnsembleFlags(interp, token, flags);
+	    return TCL_OK;
+	}
+
+    default:
+	Tcl_Panic("unexpected ensemble command");
+    }
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_CreateEnsemble --
+ *
+ *	Create a simple ensemble attached to the given namespace.
+ *
+ * Results:
+ *	The token for the command created.
+ *
+ * Side effects:
+ *	The ensemble is created and marked for compilation.
+ *
+ *----------------------------------------------------------------------
+ */
+
+Tcl_Command
+Tcl_CreateEnsemble(
+    Tcl_Interp *interp,
+    const char *name,
+    Tcl_Namespace *namespacePtr,
+    int flags)
+{
+    Namespace *nsPtr = (Namespace *) namespacePtr;
+    EnsembleConfig *ensemblePtr = (EnsembleConfig *)
+	    ckalloc(sizeof(EnsembleConfig));
+    Tcl_Obj *nameObj = NULL;
+
+    if (nsPtr == NULL) {
+	nsPtr = (Namespace *) TclGetCurrentNamespace(interp);
+    }
+
+    /*
+     * Make the name of the ensemble into a fully qualified name. This might
+     * allocate a temporary object.
+     */
+
+    if (!(name[0] == ':' && name[1] == ':')) {
+	nameObj = Tcl_NewStringObj(nsPtr->fullName, -1);
+	if (nsPtr->parentPtr == NULL) {
+	    Tcl_AppendStringsToObj(nameObj, name, NULL);
+	} else {
+	    Tcl_AppendStringsToObj(nameObj, "::", name, NULL);
+	}
+	Tcl_IncrRefCount(nameObj);
+	name = TclGetString(nameObj);
+    }
+
+    ensemblePtr->nsPtr = nsPtr;
+    ensemblePtr->epoch = 0;
+    Tcl_InitHashTable(&ensemblePtr->subcommandTable, TCL_STRING_KEYS);
+    ensemblePtr->subcommandArrayPtr = NULL;
+    ensemblePtr->subcmdList = NULL;
+    ensemblePtr->subcommandDict = NULL;
+    ensemblePtr->flags = flags;
+    ensemblePtr->numParameters = 0;
+    ensemblePtr->parameterList = NULL;
+    ensemblePtr->unknownHandler = NULL;
+    ensemblePtr->token = Tcl_NRCreateCommand(interp, name,
+	    NsEnsembleImplementationCmd, NsEnsembleImplementationCmdNR,
+	    ensemblePtr, DeleteEnsembleConfig);
+    ensemblePtr->next = (EnsembleConfig *) nsPtr->ensembles;
+    nsPtr->ensembles = (Tcl_Ensemble *) ensemblePtr;
+
+    /*
+     * Trigger an eventual recomputation of the ensemble command set. Note
+     * that this is slightly tricky, as it means that we are not actually
+     * counting the number of namespace export actions, but it is the simplest
+     * way to go!
+     */
+
+    nsPtr->exportLookupEpoch++;
+
+    if (flags & ENSEMBLE_COMPILE) {
+	((Command *) ensemblePtr->token)->compileProc = TclCompileEnsemble;
+    }
+
+    if (nameObj != NULL) {
+	TclDecrRefCount(nameObj);
+    }
+    return ensemblePtr->token;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_SetEnsembleSubcommandList --
+ *
+ *	Set the subcommand list for a particular ensemble.
+ *
+ * Results:
+ *	Tcl result code (error if command token does not indicate an ensemble
+ *	or the subcommand list - if non-NULL - is not a list).
+ *
+ * Side effects:
+ *	The ensemble is updated and marked for recompilation.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+Tcl_SetEnsembleSubcommandList(
+    Tcl_Interp *interp,
+    Tcl_Command token,
+    Tcl_Obj *subcmdList)
+{
+    Command *cmdPtr = (Command *) token;
+    EnsembleConfig *ensemblePtr;
+    Tcl_Obj *oldList;
+
+    if (cmdPtr->objProc != NsEnsembleImplementationCmd) {
+	Tcl_AppendResult(interp, "command is not an ensemble", NULL);
+	return TCL_ERROR;
+    }
+    if (subcmdList != NULL) {
+	int length;
+
+	if (TclListObjLength(interp, subcmdList, &length) != TCL_OK) {
+	    return TCL_ERROR;
+	}
+	if (length < 1) {
+	    subcmdList = NULL;
+	}
+    }
+
+    ensemblePtr = cmdPtr->objClientData;
+    oldList = ensemblePtr->subcmdList;
+    ensemblePtr->subcmdList = subcmdList;
+    if (subcmdList != NULL) {
+	Tcl_IncrRefCount(subcmdList);
+    }
+    if (oldList != NULL) {
+	TclDecrRefCount(oldList);
+    }
+
+    /*
+     * Trigger an eventual recomputation of the ensemble command set. Note
+     * that this is slightly tricky, as it means that we are not actually
+     * counting the number of namespace export actions, but it is the simplest
+     * way to go!
+     */
+
+    ensemblePtr->nsPtr->exportLookupEpoch++;
+
+    /*
+     * Special hack to make compiling of [info exists] work when the
+     * dictionary is modified.
+     */
+
+    if (cmdPtr->compileProc != NULL) {
+	((Interp *) interp)->compileEpoch++;
+    }
+
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_SetEnsembleParameterList --
+ *
+ *	Set the parameter list for a particular ensemble.
+ *
+ * Results:
+ *	Tcl result code (error if command token does not indicate an ensemble
+ *	or the parameter list - if non-NULL - is not a list).
+ *
+ * Side effects:
+ *	The ensemble is updated and marked for recompilation.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+Tcl_SetEnsembleParameterList(
+    Tcl_Interp *interp,
+    Tcl_Command token,
+    Tcl_Obj *paramList)
+{
+    Command *cmdPtr = (Command *) token;
+    EnsembleConfig *ensemblePtr;
+    Tcl_Obj *oldList;
+    int length;
+
+    if (cmdPtr->objProc != NsEnsembleImplementationCmd) {
+	Tcl_AppendResult(interp, "command is not an ensemble", NULL);
+	return TCL_ERROR;
+    }
+    if (paramList == NULL) {
+	length = 0;
+    } else {
+	if (TclListObjLength(interp, paramList, &length) != TCL_OK) {
+	    return TCL_ERROR;
+	}
+	if (length < 1) {
+	    paramList = NULL;
+	}
+    }
+
+    ensemblePtr = cmdPtr->objClientData;
+    oldList = ensemblePtr->parameterList;
+    ensemblePtr->parameterList = paramList;
+    if (paramList != NULL) {
+	Tcl_IncrRefCount(paramList);
+    }
+    if (oldList != NULL) {
+	TclDecrRefCount(oldList);
+    }
+    ensemblePtr->numParameters = length;
+
+    /*
+     * Trigger an eventual recomputation of the ensemble command set. Note
+     * that this is slightly tricky, as it means that we are not actually
+     * counting the number of namespace export actions, but it is the simplest
+     * way to go!
+     */
+
+    ensemblePtr->nsPtr->exportLookupEpoch++;
+
+    /*
+     * Special hack to make compiling of [info exists] work when the
+     * dictionary is modified.
+     */
+
+    if (cmdPtr->compileProc != NULL) {
+	((Interp *) interp)->compileEpoch++;
+    }
+
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_SetEnsembleMappingDict --
+ *
+ *	Set the mapping dictionary for a particular ensemble.
+ *
+ * Results:
+ *	Tcl result code (error if command token does not indicate an ensemble
+ *	or the mapping - if non-NULL - is not a dict).
+ *
+ * Side effects:
+ *	The ensemble is updated and marked for recompilation.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+Tcl_SetEnsembleMappingDict(
+    Tcl_Interp *interp,
+    Tcl_Command token,
+    Tcl_Obj *mapDict)
+{
+    Command *cmdPtr = (Command *) token;
+    EnsembleConfig *ensemblePtr;
+    Tcl_Obj *oldDict;
+
+    if (cmdPtr->objProc != NsEnsembleImplementationCmd) {
+	Tcl_AppendResult(interp, "command is not an ensemble", NULL);
+	return TCL_ERROR;
+    }
+    if (mapDict != NULL) {
+	int size, done;
+	Tcl_DictSearch search;
+	Tcl_Obj *valuePtr;
+
+	if (Tcl_DictObjSize(interp, mapDict, &size) != TCL_OK) {
+	    return TCL_ERROR;
+	}
+
+	for (Tcl_DictObjFirst(NULL, mapDict, &search, NULL, &valuePtr, &done);
+		!done; Tcl_DictObjNext(&search, NULL, &valuePtr, &done)) {
+	    Tcl_Obj *cmdPtr;
+	    const char *bytes;
+
+	    if (Tcl_ListObjIndex(interp, valuePtr, 0, &cmdPtr) != TCL_OK) {
+		Tcl_DictObjDone(&search);
+		return TCL_ERROR;
+	    }
+	    bytes = TclGetString(cmdPtr);
+	    if (bytes[0] != ':' || bytes[1] != ':') {
+		Tcl_AppendResult(interp,
+			"ensemble target is not a fully-qualified command",
+			NULL);
+		Tcl_DictObjDone(&search);
+		return TCL_ERROR;
+	    }
+	}
+
+	if (size < 1) {
+	    mapDict = NULL;
+	}
+    }
+
+    ensemblePtr = cmdPtr->objClientData;
+    oldDict = ensemblePtr->subcommandDict;
+    ensemblePtr->subcommandDict = mapDict;
+    if (mapDict != NULL) {
+	Tcl_IncrRefCount(mapDict);
+    }
+    if (oldDict != NULL) {
+	TclDecrRefCount(oldDict);
+    }
+
+    /*
+     * Trigger an eventual recomputation of the ensemble command set. Note
+     * that this is slightly tricky, as it means that we are not actually
+     * counting the number of namespace export actions, but it is the simplest
+     * way to go!
+     */
+
+    ensemblePtr->nsPtr->exportLookupEpoch++;
+
+    /*
+     * Special hack to make compiling of [info exists] work when the
+     * dictionary is modified.
+     */
+
+    if (cmdPtr->compileProc != NULL) {
+	((Interp *) interp)->compileEpoch++;
+    }
+
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_SetEnsembleUnknownHandler --
+ *
+ *	Set the unknown handler for a particular ensemble.
+ *
+ * Results:
+ *	Tcl result code (error if command token does not indicate an ensemble
+ *	or the unknown handler - if non-NULL - is not a list).
+ *
+ * Side effects:
+ *	The ensemble is updated and marked for recompilation.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+Tcl_SetEnsembleUnknownHandler(
+    Tcl_Interp *interp,
+    Tcl_Command token,
+    Tcl_Obj *unknownList)
+{
+    Command *cmdPtr = (Command *) token;
+    EnsembleConfig *ensemblePtr;
+    Tcl_Obj *oldList;
+
+    if (cmdPtr->objProc != NsEnsembleImplementationCmd) {
+	Tcl_AppendResult(interp, "command is not an ensemble", NULL);
+	return TCL_ERROR;
+    }
+    if (unknownList != NULL) {
+	int length;
+
+	if (TclListObjLength(interp, unknownList, &length) != TCL_OK) {
+	    return TCL_ERROR;
+	}
+	if (length < 1) {
+	    unknownList = NULL;
+	}
+    }
+
+    ensemblePtr = cmdPtr->objClientData;
+    oldList = ensemblePtr->unknownHandler;
+    ensemblePtr->unknownHandler = unknownList;
+    if (unknownList != NULL) {
+	Tcl_IncrRefCount(unknownList);
+    }
+    if (oldList != NULL) {
+	TclDecrRefCount(oldList);
+    }
+
+    /*
+     * Trigger an eventual recomputation of the ensemble command set. Note
+     * that this is slightly tricky, as it means that we are not actually
+     * counting the number of namespace export actions, but it is the simplest
+     * way to go!
+     */
+
+    ensemblePtr->nsPtr->exportLookupEpoch++;
+
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_SetEnsembleFlags --
+ *
+ *	Set the flags for a particular ensemble.
+ *
+ * Results:
+ *	Tcl result code (error if command token does not indicate an
+ *	ensemble).
+ *
+ * Side effects:
+ *	The ensemble is updated and marked for recompilation.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+Tcl_SetEnsembleFlags(
+    Tcl_Interp *interp,
+    Tcl_Command token,
+    int flags)
+{
+    Command *cmdPtr = (Command *) token;
+    EnsembleConfig *ensemblePtr;
+    int wasCompiled;
+
+    if (cmdPtr->objProc != NsEnsembleImplementationCmd) {
+	Tcl_AppendResult(interp, "command is not an ensemble", NULL);
+	return TCL_ERROR;
+    }
+
+    ensemblePtr = cmdPtr->objClientData;
+    wasCompiled = ensemblePtr->flags & ENSEMBLE_COMPILE;
+
+    /*
+     * This API refuses to set the ENSEMBLE_DEAD flag...
+     */
+
+    ensemblePtr->flags &= ENSEMBLE_DEAD;
+    ensemblePtr->flags |= flags & ~ENSEMBLE_DEAD;
+
+    /*
+     * Trigger an eventual recomputation of the ensemble command set. Note
+     * that this is slightly tricky, as it means that we are not actually
+     * counting the number of namespace export actions, but it is the simplest
+     * way to go!
+     */
+
+    ensemblePtr->nsPtr->exportLookupEpoch++;
+
+    /*
+     * If the ENSEMBLE_COMPILE flag status was changed, install or remove the
+     * compiler function and bump the interpreter's compilation epoch so that
+     * bytecode gets regenerated.
+     */
+
+    if (flags & ENSEMBLE_COMPILE) {
+	if (!wasCompiled) {
+	    ((Command*) ensemblePtr->token)->compileProc = TclCompileEnsemble;
+	    ((Interp *) interp)->compileEpoch++;
+	}
+    } else {
+	if (wasCompiled) {
+	    ((Command *) ensemblePtr->token)->compileProc = NULL;
+	    ((Interp *) interp)->compileEpoch++;
+	}
+    }
+
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_GetEnsembleSubcommandList --
+ *
+ *	Get the list of subcommands associated with a particular ensemble.
+ *
+ * Results:
+ *	Tcl result code (error if command token does not indicate an
+ *	ensemble). The list of subcommands is returned by updating the
+ *	variable pointed to by the last parameter (NULL if this is to be
+ *	derived from the mapping dictionary or the associated namespace's
+ *	exported commands).
+ *
+ * Side effects:
+ *	None
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+Tcl_GetEnsembleSubcommandList(
+    Tcl_Interp *interp,
+    Tcl_Command token,
+    Tcl_Obj **subcmdListPtr)
+{
+    Command *cmdPtr = (Command *) token;
+    EnsembleConfig *ensemblePtr;
+
+    if (cmdPtr->objProc != NsEnsembleImplementationCmd) {
+	if (interp != NULL) {
+	    Tcl_AppendResult(interp, "command is not an ensemble", NULL);
+	}
+	return TCL_ERROR;
+    }
+
+    ensemblePtr = cmdPtr->objClientData;
+    *subcmdListPtr = ensemblePtr->subcmdList;
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_GetEnsembleParameterList --
+ *
+ *	Get the list of parameters associated with a particular ensemble.
+ *
+ * Results:
+ *	Tcl result code (error if command token does not indicate an
+ *	ensemble). The list of parameters is returned by updating the
+ *	variable pointed to by the last parameter (NULL if there are
+ *	no parameters).
+ *
+ * Side effects:
+ *	None
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+Tcl_GetEnsembleParameterList(
+    Tcl_Interp *interp,
+    Tcl_Command token,
+    Tcl_Obj **paramListPtr)
+{
+    Command *cmdPtr = (Command *) token;
+    EnsembleConfig *ensemblePtr;
+
+    if (cmdPtr->objProc != NsEnsembleImplementationCmd) {
+	if (interp != NULL) {
+	    Tcl_AppendResult(interp, "command is not an ensemble", NULL);
+	}
+	return TCL_ERROR;
+    }
+
+    ensemblePtr = cmdPtr->objClientData;
+    *paramListPtr = ensemblePtr->parameterList;
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_GetEnsembleMappingDict --
+ *
+ *	Get the command mapping dictionary associated with a particular
+ *	ensemble.
+ *
+ * Results:
+ *	Tcl result code (error if command token does not indicate an
+ *	ensemble). The mapping dict is returned by updating the variable
+ *	pointed to by the last parameter (NULL if none is installed).
+ *
+ * Side effects:
+ *	None
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+Tcl_GetEnsembleMappingDict(
+    Tcl_Interp *interp,
+    Tcl_Command token,
+    Tcl_Obj **mapDictPtr)
+{
+    Command *cmdPtr = (Command *) token;
+    EnsembleConfig *ensemblePtr;
+
+    if (cmdPtr->objProc != NsEnsembleImplementationCmd) {
+	if (interp != NULL) {
+	    Tcl_AppendResult(interp, "command is not an ensemble", NULL);
+	}
+	return TCL_ERROR;
+    }
+
+    ensemblePtr = cmdPtr->objClientData;
+    *mapDictPtr = ensemblePtr->subcommandDict;
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_GetEnsembleUnknownHandler --
+ *
+ *	Get the unknown handler associated with a particular ensemble.
+ *
+ * Results:
+ *	Tcl result code (error if command token does not indicate an
+ *	ensemble). The unknown handler is returned by updating the variable
+ *	pointed to by the last parameter (NULL if no handler is installed).
+ *
+ * Side effects:
+ *	None
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+Tcl_GetEnsembleUnknownHandler(
+    Tcl_Interp *interp,
+    Tcl_Command token,
+    Tcl_Obj **unknownListPtr)
+{
+    Command *cmdPtr = (Command *) token;
+    EnsembleConfig *ensemblePtr;
+
+    if (cmdPtr->objProc != NsEnsembleImplementationCmd) {
+	if (interp != NULL) {
+	    Tcl_AppendResult(interp, "command is not an ensemble", NULL);
+	}
+	return TCL_ERROR;
+    }
+
+    ensemblePtr = cmdPtr->objClientData;
+    *unknownListPtr = ensemblePtr->unknownHandler;
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_GetEnsembleFlags --
+ *
+ *	Get the flags for a particular ensemble.
+ *
+ * Results:
+ *	Tcl result code (error if command token does not indicate an
+ *	ensemble). The flags are returned by updating the variable pointed to
+ *	by the last parameter.
+ *
+ * Side effects:
+ *	None
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+Tcl_GetEnsembleFlags(
+    Tcl_Interp *interp,
+    Tcl_Command token,
+    int *flagsPtr)
+{
+    Command *cmdPtr = (Command *) token;
+    EnsembleConfig *ensemblePtr;
+
+    if (cmdPtr->objProc != NsEnsembleImplementationCmd) {
+	if (interp != NULL) {
+	    Tcl_AppendResult(interp, "command is not an ensemble", NULL);
+	}
+	return TCL_ERROR;
+    }
+
+    ensemblePtr = cmdPtr->objClientData;
+    *flagsPtr = ensemblePtr->flags;
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_GetEnsembleNamespace --
+ *
+ *	Get the namespace associated with a particular ensemble.
+ *
+ * Results:
+ *	Tcl result code (error if command token does not indicate an
+ *	ensemble). Namespace is returned by updating the variable pointed to
+ *	by the last parameter.
+ *
+ * Side effects:
+ *	None
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+Tcl_GetEnsembleNamespace(
+    Tcl_Interp *interp,
+    Tcl_Command token,
+    Tcl_Namespace **namespacePtrPtr)
+{
+    Command *cmdPtr = (Command *) token;
+    EnsembleConfig *ensemblePtr;
+
+    if (cmdPtr->objProc != NsEnsembleImplementationCmd) {
+	if (interp != NULL) {
+	    Tcl_AppendResult(interp, "command is not an ensemble", NULL);
+	}
+	return TCL_ERROR;
+    }
+
+    ensemblePtr = cmdPtr->objClientData;
+    *namespacePtrPtr = (Tcl_Namespace *) ensemblePtr->nsPtr;
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_FindEnsemble --
+ *
+ *	Given a command name, get the ensemble token for it, allowing for
+ *	[namespace import]s. [Bug 1017022]
+ *
+ * Results:
+ *	The token for the ensemble command with the given name, or NULL if the
+ *	command either does not exist or is not an ensemble (when an error
+ *	message will be written into the interp if thats non-NULL).
+ *
+ * Side effects:
+ *	None
+ *
+ *----------------------------------------------------------------------
+ */
+
+Tcl_Command
+Tcl_FindEnsemble(
+    Tcl_Interp *interp,		/* Where to do the lookup, and where to write
+				 * the errors if TCL_LEAVE_ERR_MSG is set in
+				 * the flags. */
+    Tcl_Obj *cmdNameObj,	/* Name of command to look up. */
+    int flags)			/* Either 0 or TCL_LEAVE_ERR_MSG; other flags
+				 * are probably not useful. */
+{
+    Command *cmdPtr;
+
+    cmdPtr = (Command *)
+	    Tcl_FindCommand(interp, TclGetString(cmdNameObj), NULL, flags);
+    if (cmdPtr == NULL) {
+	return NULL;
+    }
+
+    if (cmdPtr->objProc != NsEnsembleImplementationCmd) {
+	/*
+	 * Reuse existing infrastructure for following import link chains
+	 * rather than duplicating it.
+	 */
+
+	cmdPtr = (Command *) TclGetOriginalCommand((Tcl_Command) cmdPtr);
+
+	if (cmdPtr == NULL || cmdPtr->objProc != NsEnsembleImplementationCmd){
+	    if (flags & TCL_LEAVE_ERR_MSG) {
+		Tcl_AppendResult(interp, "\"", TclGetString(cmdNameObj),
+			"\" is not an ensemble command", NULL);
+		Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "ENSEMBLE",
+			TclGetString(cmdNameObj), NULL);
+	    }
+	    return NULL;
+	}
+    }
+
+    return (Tcl_Command) cmdPtr;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_IsEnsemble --
+ *
+ *	Simple test for ensemble-hood that takes into account imported
+ *	ensemble commands as well.
+ *
+ * Results:
+ *	Boolean value
+ *
+ * Side effects:
+ *	None
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+Tcl_IsEnsemble(
+    Tcl_Command token)
+{
+    Command *cmdPtr = (Command *) token;
+
+    if (cmdPtr->objProc == NsEnsembleImplementationCmd) {
+	return 1;
+    }
+    cmdPtr = (Command *) TclGetOriginalCommand((Tcl_Command) cmdPtr);
+    if (cmdPtr == NULL || cmdPtr->objProc != NsEnsembleImplementationCmd) {
+	return 0;
+    }
+    return 1;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclMakeEnsemble --
+ *
+ *	Create an ensemble from a table of implementation commands. The
+ *	ensemble will be subject to (limited) compilation if any of the
+ *	implementation commands are compilable.
+ *
+ *	The 'name' parameter may be a single command name or a list if
+ *	creating an ensemble subcommand (see the binary implementation).
+ *
+ *	Currently, the TCL_ENSEMBLE_PREFIX ensemble flag is only used on
+ *	top-level ensemble commands.
+ *
+ * Results:
+ *	Handle for the new ensemble, or NULL on failure.
+ *
+ * Side effects:
+ *	May advance the bytecode compilation epoch.
+ *
+ *----------------------------------------------------------------------
+ */
+
+Tcl_Command
+TclMakeEnsemble(
+    Tcl_Interp *interp,
+    const char *name,		 /* The ensemble name (as explained above) */
+    const EnsembleImplMap map[]) /* The subcommands to create */
+{
+    Tcl_Command ensemble;
+    Tcl_Namespace *ns;
+    Tcl_DString buf;
+    const char **nameParts = NULL;
+    const char *cmdName = NULL;
+    int i, nameCount = 0, ensembleFlags = 0;
+
+    /*
+     * Construct the path for the ensemble namespace and create it.
+     */
+
+    Tcl_DStringInit(&buf);
+    if (name[0] == ':' && name[1] == ':') {
+	/*
+	 * An absolute name, so use it directly.
+	 */
+
+	cmdName = name;
+	Tcl_DStringAppend(&buf, name, -1);
+	ensembleFlags = TCL_ENSEMBLE_PREFIX;
+    } else {
+	/*
+	 * Not an absolute name, so do munging of it. Note that this treats a
+	 * multi-word list differently to a single word.
+	 */
+
+	Tcl_DStringAppend(&buf, "::tcl", -1);
+
+	if (Tcl_SplitList(NULL, name, &nameCount, &nameParts) != TCL_OK) {
+	    Tcl_Panic("invalid ensemble name '%s'", name);
+	}
+
+	for (i = 0; i < nameCount; ++i) {
+	    Tcl_DStringAppend(&buf, "::", 2);
+	    Tcl_DStringAppend(&buf, nameParts[i], -1);
+	}
+    }
+
+    ns = Tcl_FindNamespace(interp, Tcl_DStringValue(&buf), NULL,
+	    TCL_CREATE_NS_IF_UNKNOWN);
+    if (!ns) {
+	Tcl_Panic("unable to find or create %s namespace!",
+		Tcl_DStringValue(&buf));
+    }
+
+    /*
+     * Create the named ensemble in the correct namespace
+     */
+
+    if (cmdName == NULL) {
+	if (nameCount == 1) {
+	    ensembleFlags = TCL_ENSEMBLE_PREFIX;
+	    cmdName = Tcl_DStringValue(&buf) + 5;
+	} else {
+	    ns = ns->parentPtr;
+	    cmdName = nameParts[nameCount - 1];
+	}
+    }
+    ensemble = Tcl_CreateEnsemble(interp, cmdName, ns, ensembleFlags);
+
+    /*
+     * Create the ensemble mapping dictionary and the ensemble command procs.
+     */
+
+    if (ensemble != NULL) {
+	Tcl_Obj *mapDict, *fromObj, *toObj;
+	Command *cmdPtr;
+
+	Tcl_DStringAppend(&buf, "::", 2);
+	TclNewObj(mapDict);
+	for (i=0 ; map[i].name != NULL ; i++) {
+	    fromObj = Tcl_NewStringObj(map[i].name, -1);
+	    TclNewStringObj(toObj, Tcl_DStringValue(&buf),
+		    Tcl_DStringLength(&buf));
+	    Tcl_AppendToObj(toObj, map[i].name, -1);
+	    Tcl_DictObjPut(NULL, mapDict, fromObj, toObj);
+	    if (map[i].proc || map[i].nreProc) {
+		cmdPtr = (Command *)
+			Tcl_NRCreateCommand(interp, TclGetString(toObj),
+			map[i].proc, map[i].nreProc, map[i].clientData, NULL);
+		cmdPtr->compileProc = map[i].compileProc;
+		if (map[i].compileProc != NULL) {
+		    ensembleFlags |= ENSEMBLE_COMPILE;
+		}
+	    }
+	}
+	Tcl_SetEnsembleMappingDict(interp, ensemble, mapDict);
+	if (ensembleFlags & ENSEMBLE_COMPILE) {
+	    Tcl_SetEnsembleFlags(interp, ensemble, ensembleFlags);
+	}
+    }
+
+    Tcl_DStringFree(&buf);
+    if (nameParts != NULL) {
+	Tcl_Free((char *) nameParts);
+    }
+    return ensemble;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * NsEnsembleImplementationCmd --
+ *
+ *	Implements an ensemble of commands (being those exported by a
+ *	namespace other than the global namespace) as a command with the same
+ *	(short) name as the namespace in the parent namespace.
+ *
+ * Results:
+ *	A standard Tcl result code. Will be TCL_ERROR if the command is not an
+ *	unambiguous prefix of any command exported by the ensemble's
+ *	namespace.
+ *
+ * Side effects:
+ *	Depends on the command within the namespace that gets executed. If the
+ *	ensemble itself returns TCL_ERROR, a descriptive error message will be
+ *	placed in the interpreter's result.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+NsEnsembleImplementationCmd(
+    ClientData clientData,
+    Tcl_Interp *interp,
+    int objc,
+    Tcl_Obj *const objv[])
+{
+    return Tcl_NRCallObjProc(interp, NsEnsembleImplementationCmdNR,
+	    clientData, objc, objv);
+}
+
+static int
+NsEnsembleImplementationCmdNR(
+    ClientData clientData,
+    Tcl_Interp *interp,
+    int objc,
+    Tcl_Obj *const objv[])
+{
+    EnsembleConfig *ensemblePtr = clientData;
+				/* The ensemble itself. */
+    Tcl_Obj *prefixObj;		/* An object containing the prefix words of
+				 * the command that implements the
+				 * subcommand. */
+    Tcl_HashEntry *hPtr;	/* Used for efficient lookup of fully
+				 * specified but not yet cached command
+				 * names. */
+    int reparseCount = 0;	/* Number of reparses. */
+
+    /*
+     * Must recheck objc, since numParameters might have changed. Cf. test
+     * namespace-53.9.
+     */
+
+  restartEnsembleParse:
+    if (objc < 2 + ensemblePtr->numParameters) {
+	/*
+	 * We don't have a subcommand argument. Make error message.
+	 */
+
+	Tcl_DString buf;	/* Message being built */
+	Tcl_Obj **elemPtrs;	/* Parameter names */
+	int len;		/* Number of parameters to append */
+
+	Tcl_DStringInit(&buf);
+	if (ensemblePtr->parameterList == NULL) {
+	    len = 0;
+	} else if (TclListObjGetElements(NULL, ensemblePtr->parameterList,
+		&len, &elemPtrs) != TCL_OK) {
+	    Tcl_Panic("List of ensemble parameters is not a list");
+	}
+	for (; len>0; len--,elemPtrs++) {
+	    Tcl_DStringAppend(&buf, Tcl_GetString(*elemPtrs), -1);
+	    Tcl_DStringAppend(&buf, " ", -1);
+	}
+	Tcl_DStringAppend(&buf, "subcommand ?arg ...?", -1);
+	Tcl_WrongNumArgs(interp, 1, objv, Tcl_DStringValue(&buf));
+	Tcl_DStringFree(&buf);
+
+	return TCL_ERROR;
+    }
+
+    if (ensemblePtr->nsPtr->flags & NS_DYING) {
+	/*
+	 * Don't know how we got here, but make things give up quickly.
+	 */
+
+	if (!Tcl_InterpDeleted(interp)) {
+	    Tcl_AppendResult(interp,
+		    "ensemble activated for deleted namespace", NULL);
+	}
+	return TCL_ERROR;
+    }
+
+    /*
+     * Determine if the table of subcommands is right. If so, we can just look
+     * up in there and go straight to dispatch.
+     */
+
+    if (ensemblePtr->epoch == ensemblePtr->nsPtr->exportLookupEpoch) {
+	/*
+	 * Table of subcommands is still valid; therefore there might be a
+	 * valid cache of discovered information which we can reuse. Do the
+	 * check here, and if we're still valid, we can jump straight to the
+	 * part where we do the invocation of the subcommand.
+	 */
+
+	if (objv[1+ensemblePtr->numParameters]->typePtr==&tclEnsembleCmdType){
+	    EnsembleCmdRep *ensembleCmd = objv[1+ensemblePtr->numParameters]
+		    ->internalRep.otherValuePtr;
+
+	    if (ensembleCmd->nsPtr == ensemblePtr->nsPtr &&
+		    ensembleCmd->epoch == ensemblePtr->epoch &&
+		    ensembleCmd->token == ensemblePtr->token) {
+		prefixObj = ensembleCmd->realPrefixObj;
+		Tcl_IncrRefCount(prefixObj);
+		goto runResultingSubcommand;
+	    }
+	}
+    } else {
+	BuildEnsembleConfig(ensemblePtr);
+	ensemblePtr->epoch = ensemblePtr->nsPtr->exportLookupEpoch;
+    }
+
+    /*
+     * Look in the hashtable for the subcommand name; this is the fastest way
+     * of all if there is no cache in operation.
+     */
+
+    hPtr = Tcl_FindHashEntry(&ensemblePtr->subcommandTable,
+	    TclGetString(objv[1 + ensemblePtr->numParameters]));
+    if (hPtr != NULL) {
+	char *fullName = Tcl_GetHashKey(&ensemblePtr->subcommandTable, hPtr);
+
+	prefixObj = Tcl_GetHashValue(hPtr);
+
+	/*
+	 * Cache for later in the subcommand object.
+	 */
+
+	MakeCachedEnsembleCommand(objv[1 + ensemblePtr->numParameters],
+		ensemblePtr, fullName, prefixObj);
+    } else if (!(ensemblePtr->flags & TCL_ENSEMBLE_PREFIX)) {
+	/*
+	 * Could not map, no prefixing, go to unknown/error handling.
+	 */
+
+	goto unknownOrAmbiguousSubcommand;
+    } else {
+	/*
+	 * If we've not already confirmed the command with the hash as part of
+	 * building our export table, we need to scan the sorted array for
+	 * matches.
+	 */
+
+	const char *subcmdName; /* Name of the subcommand, or unique prefix of
+				 * it (will be an error for a non-unique
+				 * prefix). */
+	char *fullName = NULL;	/* Full name of the subcommand. */
+	int stringLength, i;
+	int tableLength = ensemblePtr->subcommandTable.numEntries;
+
+	subcmdName = TclGetString(objv[1 + ensemblePtr->numParameters]);
+	stringLength = objv[1 + ensemblePtr->numParameters]->length;
+	for (i=0 ; i<tableLength ; i++) {
+	    register int cmp = strncmp(subcmdName,
+		    ensemblePtr->subcommandArrayPtr[i],
+		    (unsigned) stringLength);
+
+	    if (cmp == 0) {
+		if (fullName != NULL) {
+		    /*
+		     * Since there's never the exact-match case to worry about
+		     * (hash search filters this), getting here indicates that
+		     * our subcommand is an ambiguous prefix of (at least) two
+		     * exported subcommands, which is an error case.
+		     */
+
+		    goto unknownOrAmbiguousSubcommand;
+		}
+		fullName = ensemblePtr->subcommandArrayPtr[i];
+	    } else if (cmp < 0) {
+		/*
+		 * Because we are searching a sorted table, we can now stop
+		 * searching because we have gone past anything that could
+		 * possibly match.
+		 */
+
+		break;
+	    }
+	}
+	if (fullName == NULL) {
+	    /*
+	     * The subcommand is not a prefix of anything, so bail out!
+	     */
+
+	    goto unknownOrAmbiguousSubcommand;
+	}
+	hPtr = Tcl_FindHashEntry(&ensemblePtr->subcommandTable, fullName);
+	if (hPtr == NULL) {
+	    Tcl_Panic("full name %s not found in supposedly synchronized hash",
+		    fullName);
+	}
+	prefixObj = Tcl_GetHashValue(hPtr);
+
+	/*
+	 * Cache for later in the subcommand object.
+	 */
+
+	MakeCachedEnsembleCommand(objv[1 + ensemblePtr->numParameters],
+		ensemblePtr, fullName, prefixObj);
+    }
+
+    Tcl_IncrRefCount(prefixObj);
+  runResultingSubcommand:
+
+    /*
+     * Do the real work of execution of the subcommand by building an array of
+     * objects (note that this is potentially not the same length as the
+     * number of arguments to this ensemble command), populating it and then
+     * feeding it back through the main command-lookup engine. In theory, we
+     * could look up the command in the namespace ourselves, as we already
+     * have the namespace in which it is guaranteed to exist,
+     *
+     *   ((Q: That's not true if the -map option is used, is it?))
+     *
+     * but we don't do that (the cacheing of the command object used should
+     * help with that.)
+     */
+
+    {
+	Tcl_Obj **prefixObjv;	/* The list of objects to substitute in as the
+				 * target command prefix. */
+	Tcl_Obj *copyPtr;	/* The actual list of words to dispatch to.
+				 * Will be freed by the dispatch engine. */
+	int prefixObjc, copyObjc;
+	Interp *iPtr = (Interp *) interp;
+
+	/*
+	 * Get the prefix that we're rewriting to. To do this we need to
+	 * ensure that the internal representation of the list does not change
+	 * so that we can safely keep the internal representations of the
+	 * elements in the list.
+	 *
+	 * TODO: Use conventional list operations to make this code sane!
+	 */
+
+	TclListObjGetElements(NULL, prefixObj, &prefixObjc, &prefixObjv);
+
+	copyObjc = objc - 2 + prefixObjc;
+	copyPtr = Tcl_NewListObj(copyObjc, NULL);
+	if (copyObjc > 0) {
+	    register Tcl_Obj **copyObjv;
+				/* Space used to construct the list of
+				 * arguments to pass to the command that
+				 * implements the ensemble subcommand. */
+	    register List *listRepPtr = copyPtr->internalRep.twoPtrValue.ptr1;
+	    register int i;
+
+	    listRepPtr->elemCount = copyObjc;
+	    copyObjv = &listRepPtr->elements;
+	    memcpy(copyObjv, prefixObjv, sizeof(Tcl_Obj *) * prefixObjc);
+	    memcpy(copyObjv+prefixObjc, objv+1,
+		    sizeof(Tcl_Obj *) * ensemblePtr->numParameters);
+	    memcpy(copyObjv+prefixObjc+ensemblePtr->numParameters,
+		    objv+ensemblePtr->numParameters+2,
+		    sizeof(Tcl_Obj *) * (objc-ensemblePtr->numParameters-2));
+
+	    for (i=0; i < copyObjc; i++) {
+		Tcl_IncrRefCount(copyObjv[i]);
+	    }
+	}
+	TclDecrRefCount(prefixObj);
+
+	/*
+	 * Record what arguments the script sent in so that things like
+	 * Tcl_WrongNumArgs can give the correct error message. Parameters
+	 * count both as inserted and removed arguments.
+	 */
+
+#if 0
+	if (TclInitRewriteEnsemble(interp, 2 + ensemblePtr->numParameters, prefixObjc + ensemblePtr->numParameters, objv)) {
+	    TclNRAddCallback(interp, TclClearRootEnsemble, NULL, NULL, NULL, NULL);
+	}
+#else
+	if (iPtr->ensembleRewrite.sourceObjs == NULL) {
+	    iPtr->ensembleRewrite.sourceObjs = objv;
+	    iPtr->ensembleRewrite.numRemovedObjs =
+		    2 + ensemblePtr->numParameters;
+	    iPtr->ensembleRewrite.numInsertedObjs =
+		    prefixObjc + ensemblePtr->numParameters;
+	    TclNRAddCallback(interp, TclClearRootEnsemble, NULL, NULL, NULL,
+		    NULL);
+	} else {
+	    register int ni = 2 + ensemblePtr->numParameters
+		    - iPtr->ensembleRewrite.numInsertedObjs;
+				/* Position in objv of new front of insertion
+				 * relative to old one. */
+	    if (ni > 0) {
+		iPtr->ensembleRewrite.numRemovedObjs += ni;
+		iPtr->ensembleRewrite.numInsertedObjs += prefixObjc-1;
+	    } else {
+		iPtr->ensembleRewrite.numInsertedObjs += prefixObjc-2;
+	    }
+	}
+#endif
+
+	/*
+	 * Hand off to the target command.
+	 */
+
+	iPtr->evalFlags |= TCL_EVAL_REDIRECT;
+	return Tcl_NREvalObj(interp, copyPtr, TCL_EVAL_INVOKE);
+    }
+
+  unknownOrAmbiguousSubcommand:
+    /*
+     * Have not been able to match the subcommand asked for with a real
+     * subcommand that we export. See whether a handler has been registered
+     * for dealing with this situation. Will only call (at most) once for any
+     * particular ensemble invocation.
+     */
+
+    if (ensemblePtr->unknownHandler != NULL && reparseCount++ < 1) {
+	switch (EnsembleUnknownCallback(interp, ensemblePtr, objc, objv,
+		&prefixObj)) {
+	case TCL_OK:
+	    goto runResultingSubcommand;
+	case TCL_ERROR:
+	    return TCL_ERROR;
+	case TCL_CONTINUE:
+	    goto restartEnsembleParse;
+	}
+    }
+
+    /*
+     * We cannot determine what subcommand to hand off to, so generate a
+     * (standard) failure message. Note the one odd case compared with
+     * standard ensemble-like command, which is where a namespace has no
+     * exported commands at all...
+     */
+
+    Tcl_ResetResult(interp);
+    Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "ENSEMBLE",
+	    TclGetString(objv[1+ensemblePtr->numParameters]), NULL);
+    if (ensemblePtr->subcommandTable.numEntries == 0) {
+	Tcl_AppendResult(interp, "unknown subcommand \"",
+		TclGetString(objv[1+ensemblePtr->numParameters]),
+		"\": namespace ", ensemblePtr->nsPtr->fullName,
+		" does not export any commands", NULL);
+	Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "SUBCOMMAND",
+		TclGetString(objv[1+ensemblePtr->numParameters]), NULL);
+	return TCL_ERROR;
+    }
+    Tcl_AppendResult(interp, "unknown ",
+	    (ensemblePtr->flags & TCL_ENSEMBLE_PREFIX ? "or ambiguous " : ""),
+	    "subcommand \"", TclGetString(objv[1+ensemblePtr->numParameters]),
+	    "\": must be ", NULL);
+    if (ensemblePtr->subcommandTable.numEntries == 1) {
+	Tcl_AppendResult(interp, ensemblePtr->subcommandArrayPtr[0], NULL);
+    } else {
+	int i;
+
+	for (i=0 ; i<ensemblePtr->subcommandTable.numEntries-1 ; i++) {
+	    Tcl_AppendResult(interp,
+		    ensemblePtr->subcommandArrayPtr[i], ", ", NULL);
+	}
+	Tcl_AppendResult(interp, "or ",
+		ensemblePtr->subcommandArrayPtr[i], NULL);
+    }
+    Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "SUBCOMMAND",
+	    TclGetString(objv[1+ensemblePtr->numParameters]), NULL);
+    return TCL_ERROR;
+}
+
+int
+TclClearRootEnsemble(
+    ClientData data[],
+    Tcl_Interp *interp,
+    int result)
+{
+    TclResetRewriteEnsemble(interp, 1);
+    return result;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclInitRewriteEnsemble --
+ *
+ *	Applies a rewrite of arguments so that an ensemble subcommand will
+ *	report error messages correctly for the overall command.
+ *
+ * Results:
+ *	Whether this is the first rewrite applied, a value which must be
+ *	passed to TclResetRewriteEnsemble when undoing this command's
+ *	behaviour.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+TclInitRewriteEnsemble(
+    Tcl_Interp *interp,
+    int numRemoved,
+    int numInserted,
+    Tcl_Obj *const *objv)
+{
+    Interp *iPtr = (Interp *) interp;
+
+    int isRootEnsemble = (iPtr->ensembleRewrite.sourceObjs == NULL);
+
+    if (isRootEnsemble) {
+	iPtr->ensembleRewrite.sourceObjs = objv;
+	iPtr->ensembleRewrite.numRemovedObjs = numRemoved;
+	iPtr->ensembleRewrite.numInsertedObjs = numInserted;
+    } else {
+	int numIns = iPtr->ensembleRewrite.numInsertedObjs;
+
+	if (numIns < numRemoved) {
+	    iPtr->ensembleRewrite.numRemovedObjs += numRemoved - numIns;
+	    iPtr->ensembleRewrite.numInsertedObjs += numInserted - 1;
+	} else {
+	    iPtr->ensembleRewrite.numInsertedObjs += numInserted - numRemoved;
+	}
+    }
+    return isRootEnsemble;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclResetRewriteEnsemble --
+ *
+ *	Removes any rewrites applied to support proper reporting of error
+ *	messages used in ensembles. Should be paired with
+ *	TclInitRewriteEnsemble.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TclResetRewriteEnsemble(
+    Tcl_Interp *interp,
+    int isRootEnsemble)
+{
+    Interp *iPtr = (Interp *) interp;
+
+    if (isRootEnsemble) {
+	iPtr->ensembleRewrite.sourceObjs = NULL;
+	iPtr->ensembleRewrite.numRemovedObjs = 0;
+	iPtr->ensembleRewrite.numInsertedObjs = 0;
+    }
+}
+
+/*
+ * ----------------------------------------------------------------------
+ *
+ * EnsmebleUnknownCallback --
+ *
+ *	Helper for the ensemble engine that handles the procesing of unknown
+ *	callbacks. See the user documentation of the ensemble unknown handler
+ *	for details; this function is only ever called when such a function is
+ *	defined, and is only ever called once per ensemble dispatch (i.e. if a
+ *	reparse still fails, this isn't called again).
+ *
+ * Results:
+ *	TCL_OK -	*prefixObjPtr contains the command words to dispatch
+ *			to.
+ *	TCL_CONTINUE -	Need to reparse (*prefixObjPtr is invalid).
+ *	TCL_ERROR -	Something went wrong! Error message in interpreter.
+ *
+ * Side effects:
+ *	Calls the Tcl interpreter, so arbitrary.
+ *
+ * ----------------------------------------------------------------------
+ */
+
+static inline int
+EnsembleUnknownCallback(
+    Tcl_Interp *interp,
+    EnsembleConfig *ensemblePtr,
+    int objc,
+    Tcl_Obj *const objv[],
+    Tcl_Obj **prefixObjPtr)
+{
+    int paramc, i, result, prefixObjc;
+    Tcl_Obj **paramv, *unknownCmd, *ensObj;
+    char buf[TCL_INTEGER_SPACE];
+
+    /*
+     * Create the unknown command callback to determine what to do.
+     */
+
+    unknownCmd = Tcl_DuplicateObj(ensemblePtr->unknownHandler);
+    TclNewObj(ensObj);
+    Tcl_GetCommandFullName(interp, ensemblePtr->token, ensObj);
+    Tcl_ListObjAppendElement(NULL, unknownCmd, ensObj);
+    for (i=1 ; i<objc ; i++) {
+	Tcl_ListObjAppendElement(NULL, unknownCmd, objv[i]);
+    }
+    TclListObjGetElements(NULL, unknownCmd, &paramc, &paramv);
+    Tcl_IncrRefCount(unknownCmd);
+
+    /*
+     * Now call the unknown handler. (We don't bother NRE-enabling this; deep
+     * recursing through unknown handlers is horribly perverse.) Note that it
+     * is always an error for an unknown handler to delete its ensemble; don't
+     * do that!
+     */
+
+    Tcl_Preserve(ensemblePtr);
+    ((Interp *) interp)->evalFlags |= TCL_EVAL_REDIRECT;
+    result = Tcl_EvalObjv(interp, paramc, paramv, 0);
+    if ((result == TCL_OK) && (ensemblePtr->flags & ENSEMBLE_DEAD)) {
+	Tcl_SetResult(interp,
+		"unknown subcommand handler deleted its ensemble",
+		TCL_STATIC);
+	result = TCL_ERROR;
+    }
+    Tcl_Release(ensemblePtr);
+
+    /*
+     * If we succeeded, we should either have a list of words that form the
+     * command to be executed, or an empty list. In the empty-list case, the
+     * ensemble is believed to be updated so we should ask the ensemble engine
+     * to reparse the original command.
+     */
+
+    if (result == TCL_OK) {
+	*prefixObjPtr = Tcl_GetObjResult(interp);
+	Tcl_IncrRefCount(*prefixObjPtr);
+	TclDecrRefCount(unknownCmd);
+	Tcl_ResetResult(interp);
+
+	/*
+	 * Namespace is still there. Check if the result is a valid list. If
+	 * it is, and it is non-empty, that list is what we are using as our
+	 * replacement.
+	 */
+
+	if (TclListObjLength(interp, *prefixObjPtr, &prefixObjc) != TCL_OK) {
+	    TclDecrRefCount(*prefixObjPtr);
+	    Tcl_AddErrorInfo(interp, "\n    while parsing result of "
+		    "ensemble unknown subcommand handler");
+	    return TCL_ERROR;
+	}
+	if (prefixObjc > 0) {
+	    return TCL_OK;
+	}
+
+	/*
+	 * Namespace alive & empty result => reparse.
+	 */
+
+	TclDecrRefCount(*prefixObjPtr);
+	return TCL_CONTINUE;
+    }
+
+    /*
+     * Oh no! An exceptional result. Convert to an error.
+     */
+
+    if (!Tcl_InterpDeleted(interp)) {
+	if (result != TCL_ERROR) {
+	    Tcl_ResetResult(interp);
+	    Tcl_SetResult(interp,
+		    "unknown subcommand handler returned bad code: ",
+		    TCL_STATIC);
+	    switch (result) {
+	    case TCL_RETURN:
+		Tcl_AppendResult(interp, "return", NULL);
+		break;
+	    case TCL_BREAK:
+		Tcl_AppendResult(interp, "break", NULL);
+		break;
+	    case TCL_CONTINUE:
+		Tcl_AppendResult(interp, "continue", NULL);
+		break;
+	    default:
+		sprintf(buf, "%d", result);
+		Tcl_AppendResult(interp, buf, NULL);
+	    }
+	    Tcl_AddErrorInfo(interp, "\n    result of "
+		    "ensemble unknown subcommand handler: ");
+	    Tcl_AddErrorInfo(interp, TclGetString(unknownCmd));
+	} else {
+	    Tcl_AddErrorInfo(interp,
+		    "\n    (ensemble unknown subcommand handler)");
+	}
+    }
+    TclDecrRefCount(unknownCmd);
+    return TCL_ERROR;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * MakeCachedEnsembleCommand --
+ *
+ *	Cache what we've computed so far; it's not nice to repeatedly copy
+ *	strings about. Note that to do this, we start by deleting any old
+ *	representation that there was (though if it was an out of date
+ *	ensemble rep, we can skip some of the deallocation process.)
+ *
+ * Results:
+ *	None
+ *
+ * Side effects:
+ *	Alters the internal representation of the first object parameter.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+MakeCachedEnsembleCommand(
+    Tcl_Obj *objPtr,
+    EnsembleConfig *ensemblePtr,
+    const char *subcommandName,
+    Tcl_Obj *prefixObjPtr)
+{
+    register EnsembleCmdRep *ensembleCmd;
+    int length;
+
+    if (objPtr->typePtr == &tclEnsembleCmdType) {
+	ensembleCmd = objPtr->internalRep.otherValuePtr;
+	Tcl_DecrRefCount(ensembleCmd->realPrefixObj);
+	TclNsDecrRefCount(ensembleCmd->nsPtr);
+	ckfree(ensembleCmd->fullSubcmdName);
+    } else {
+	/*
+	 * Kill the old internal rep, and replace it with a brand new one of
+	 * our own.
+	 */
+
+	TclFreeIntRep(objPtr);
+	ensembleCmd = (EnsembleCmdRep *) ckalloc(sizeof(EnsembleCmdRep));
+	objPtr->internalRep.otherValuePtr = ensembleCmd;
+	objPtr->typePtr = &tclEnsembleCmdType;
+    }
+
+    /*
+     * Populate the internal rep.
+     */
+
+    ensembleCmd->nsPtr = ensemblePtr->nsPtr;
+    ensembleCmd->epoch = ensemblePtr->epoch;
+    ensembleCmd->token = ensemblePtr->token;
+    ensemblePtr->nsPtr->refCount++;
+    ensembleCmd->realPrefixObj = prefixObjPtr;
+    length = strlen(subcommandName)+1;
+    ensembleCmd->fullSubcmdName = ckalloc((unsigned) length);
+    memcpy(ensembleCmd->fullSubcmdName, subcommandName, (unsigned) length);
+    Tcl_IncrRefCount(ensembleCmd->realPrefixObj);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * DeleteEnsembleConfig --
+ *
+ *	Destroys the data structure used to represent an ensemble. This is
+ *	called when the ensemble's command is deleted (which happens
+ *	automatically if the ensemble's namespace is deleted.) Maintainers
+ *	should note that ensembles should be deleted by deleting their
+ *	commands.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Memory is (eventually) deallocated.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+DeleteEnsembleConfig(
+    ClientData clientData)
+{
+    EnsembleConfig *ensemblePtr = clientData;
+    Namespace *nsPtr = ensemblePtr->nsPtr;
+    Tcl_HashSearch search;
+    Tcl_HashEntry *hEnt;
+
+    /*
+     * Unlink from the ensemble chain if it has not been marked as having been
+     * done already.
+     */
+
+    if (ensemblePtr->next != ensemblePtr) {
+	EnsembleConfig *ensPtr = (EnsembleConfig *) nsPtr->ensembles;
+
+	if (ensPtr == ensemblePtr) {
+	    nsPtr->ensembles = (Tcl_Ensemble *) ensemblePtr->next;
+	} else {
+	    while (ensPtr != NULL) {
+		if (ensPtr->next == ensemblePtr) {
+		    ensPtr->next = ensemblePtr->next;
+		    break;
+		}
+		ensPtr = ensPtr->next;
+	    }
+	}
+    }
+
+    /*
+     * Mark the namespace as dead so code that uses Tcl_Preserve() can tell
+     * whether disaster happened anyway.
+     */
+
+    ensemblePtr->flags |= ENSEMBLE_DEAD;
+
+    /*
+     * Kill the pointer-containing fields.
+     */
+
+    if (ensemblePtr->subcommandTable.numEntries != 0) {
+	ckfree((char *) ensemblePtr->subcommandArrayPtr);
+    }
+    hEnt = Tcl_FirstHashEntry(&ensemblePtr->subcommandTable, &search);
+    while (hEnt != NULL) {
+	Tcl_Obj *prefixObj = Tcl_GetHashValue(hEnt);
+
+	Tcl_DecrRefCount(prefixObj);
+	hEnt = Tcl_NextHashEntry(&search);
+    }
+    Tcl_DeleteHashTable(&ensemblePtr->subcommandTable);
+    if (ensemblePtr->subcmdList != NULL) {
+	Tcl_DecrRefCount(ensemblePtr->subcmdList);
+    }
+    if (ensemblePtr->parameterList != NULL) {
+	Tcl_DecrRefCount(ensemblePtr->parameterList);
+    }
+    if (ensemblePtr->subcommandDict != NULL) {
+	Tcl_DecrRefCount(ensemblePtr->subcommandDict);
+    }
+    if (ensemblePtr->unknownHandler != NULL) {
+	Tcl_DecrRefCount(ensemblePtr->unknownHandler);
+    }
+
+    /*
+     * Arrange for the structure to be reclaimed. Note that this is complex
+     * because we have to make sure that we can react sensibly when an
+     * ensemble is deleted during the process of initialising the ensemble
+     * (especially the unknown callback.)
+     */
+
+    Tcl_EventuallyFree(ensemblePtr, TCL_DYNAMIC);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * BuildEnsembleConfig --
+ *
+ *	Create the internal data structures that describe how an ensemble
+ *	looks, being a hash mapping from the full command name to the Tcl list
+ *	that describes the implementation prefix words, and a sorted array of
+ *	all the full command names to allow for reasonably efficient
+ *	unambiguous prefix handling.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Reallocates and rebuilds the hash table and array stored at the
+ *	ensemblePtr argument. For large ensembles or large namespaces, this is
+ *	a potentially expensive operation.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+BuildEnsembleConfig(
+    EnsembleConfig *ensemblePtr)
+{
+    Tcl_HashSearch search;	/* Used for scanning the set of commands in
+				 * the namespace that backs up this
+				 * ensemble. */
+    int i, j, isNew;
+    Tcl_HashTable *hash = &ensemblePtr->subcommandTable;
+    Tcl_HashEntry *hPtr;
+
+    if (hash->numEntries != 0) {
+	/*
+	 * Remove pre-existing table.
+	 */
+
+	Tcl_HashSearch search;
+
+	ckfree((char *) ensemblePtr->subcommandArrayPtr);
+	hPtr = Tcl_FirstHashEntry(hash, &search);
+	while (hPtr != NULL) {
+	    Tcl_Obj *prefixObj = Tcl_GetHashValue(hPtr);
+
+	    Tcl_DecrRefCount(prefixObj);
+	    hPtr = Tcl_NextHashEntry(&search);
+	}
+	Tcl_DeleteHashTable(hash);
+	Tcl_InitHashTable(hash, TCL_STRING_KEYS);
+    }
+
+    /*
+     * See if we've got an export list. If so, we will only export exactly
+     * those commands, which may be either implemented by the prefix in the
+     * subcommandDict or mapped directly onto the namespace's commands.
+     */
+
+    if (ensemblePtr->subcmdList != NULL) {
+	Tcl_Obj **subcmdv, *target, *cmdObj, *cmdPrefixObj;
+	int subcmdc;
+
+	TclListObjGetElements(NULL, ensemblePtr->subcmdList, &subcmdc,
+		&subcmdv);
+	for (i=0 ; i<subcmdc ; i++) {
+	    const char *name = TclGetString(subcmdv[i]);
+
+	    hPtr = Tcl_CreateHashEntry(hash, name, &isNew);
+
+	    /*
+	     * Skip non-unique cases.
+	     */
+
+	    if (!isNew) {
+		continue;
+	    }
+
+	    /*
+	     * Look in our dictionary (if present) for the command.
+	     */
+
+	    if (ensemblePtr->subcommandDict != NULL) {
+		Tcl_DictObjGet(NULL, ensemblePtr->subcommandDict, subcmdv[i],
+			&target);
+		if (target != NULL) {
+		    Tcl_SetHashValue(hPtr, target);
+		    Tcl_IncrRefCount(target);
+		    continue;
+		}
+	    }
+
+	    /*
+	     * Not there, so map onto the namespace. Note in this case that we
+	     * do not guarantee that the command is actually there; that is
+	     * the programmer's responsibility (or [::unknown] of course).
+	     */
+
+	    cmdObj = Tcl_NewStringObj(ensemblePtr->nsPtr->fullName, -1);
+	    if (ensemblePtr->nsPtr->parentPtr != NULL) {
+		Tcl_AppendStringsToObj(cmdObj, "::", name, NULL);
+	    } else {
+		Tcl_AppendStringsToObj(cmdObj, name, NULL);
+	    }
+	    cmdPrefixObj = Tcl_NewListObj(1, &cmdObj);
+	    Tcl_SetHashValue(hPtr, cmdPrefixObj);
+	    Tcl_IncrRefCount(cmdPrefixObj);
+	}
+    } else if (ensemblePtr->subcommandDict != NULL) {
+	/*
+	 * No subcmd list, but we do have a mapping dictionary so we should
+	 * use the keys of that. Convert the dictionary's contents into the
+	 * form required for the ensemble's internal hashtable.
+	 */
+
+	Tcl_DictSearch dictSearch;
+	Tcl_Obj *keyObj, *valueObj;
+	int done;
+
+	Tcl_DictObjFirst(NULL, ensemblePtr->subcommandDict, &dictSearch,
+		&keyObj, &valueObj, &done);
+	while (!done) {
+	    const char *name = TclGetString(keyObj);
+
+	    hPtr = Tcl_CreateHashEntry(hash, name, &isNew);
+	    Tcl_SetHashValue(hPtr, valueObj);
+	    Tcl_IncrRefCount(valueObj);
+	    Tcl_DictObjNext(&dictSearch, &keyObj, &valueObj, &done);
+	}
+    } else {
+	/*
+	 * Discover what commands are actually exported by the namespace.
+	 * What we have is an array of patterns and a hash table whose keys
+	 * are the command names exported by the namespace (the contents do
+	 * not matter here.) We must find out what commands are actually
+	 * exported by filtering each command in the namespace against each of
+	 * the patterns in the export list. Note that we use an intermediate
+	 * hash table to make memory management easier, and because that makes
+	 * exact matching far easier too.
+	 *
+	 * Suggestion for future enhancement: compute the unique prefixes and
+	 * place them in the hash too, which should make for even faster
+	 * matching.
+	 */
+
+	hPtr = Tcl_FirstHashEntry(&ensemblePtr->nsPtr->cmdTable, &search);
+	for (; hPtr!= NULL ; hPtr=Tcl_NextHashEntry(&search)) {
+	    char *nsCmdName =		/* Name of command in namespace. */
+		    Tcl_GetHashKey(&ensemblePtr->nsPtr->cmdTable, hPtr);
+
+	    for (i=0 ; i<ensemblePtr->nsPtr->numExportPatterns ; i++) {
+		if (Tcl_StringMatch(nsCmdName,
+			ensemblePtr->nsPtr->exportArrayPtr[i])) {
+		    hPtr = Tcl_CreateHashEntry(hash, nsCmdName, &isNew);
+
+		    /*
+		     * Remember, hash entries have a full reference to the
+		     * substituted part of the command (as a list) as their
+		     * content!
+		     */
+
+		    if (isNew) {
+			Tcl_Obj *cmdObj, *cmdPrefixObj;
+
+			TclNewObj(cmdObj);
+			Tcl_AppendStringsToObj(cmdObj,
+				ensemblePtr->nsPtr->fullName,
+				(ensemblePtr->nsPtr->parentPtr ? "::" : ""),
+				nsCmdName, NULL);
+			cmdPrefixObj = Tcl_NewListObj(1, &cmdObj);
+			Tcl_SetHashValue(hPtr, cmdPrefixObj);
+			Tcl_IncrRefCount(cmdPrefixObj);
+		    }
+		    break;
+		}
+	    }
+	}
+    }
+
+    if (hash->numEntries == 0) {
+	ensemblePtr->subcommandArrayPtr = NULL;
+	return;
+    }
+
+    /*
+     * Create a sorted array of all subcommands in the ensemble; hash tables
+     * are all very well for a quick look for an exact match, but they can't
+     * determine things like whether a string is a prefix of another (not
+     * without lots of preparation anyway) and they're no good for when we're
+     * generating the error message either.
+     *
+     * We do this by filling an array with the names (we use the hash keys
+     * directly to save a copy, since any time we change the array we change
+     * the hash too, and vice versa) and running quicksort over the array.
+     */
+
+    ensemblePtr->subcommandArrayPtr = (char **)
+	    ckalloc(sizeof(char *) * hash->numEntries);
+
+    /*
+     * Fill array from both ends as this makes us less likely to end up with
+     * performance problems in qsort(), which is good. Note that doing this
+     * makes this code much more opaque, but the naive alternatve:
+     *
+     * for (hPtr=Tcl_FirstHashEntry(hash,&search),i=0 ;
+     *	       hPtr!=NULL ; hPtr=Tcl_NextHashEntry(&search),i++) {
+     *     ensemblePtr->subcommandArrayPtr[i] = Tcl_GetHashKey(hash, &hPtr);
+     * }
+     *
+     * can produce long runs of precisely ordered table entries when the
+     * commands in the namespace are declared in a sorted fashion (an ordering
+     * some people like) and the hashing functions (or the command names
+     * themselves) are fairly unfortunate. By filling from both ends, it
+     * requires active malice (and probably a debugger) to get qsort() to have
+     * awful runtime behaviour.
+     */
+
+    i = 0;
+    j = hash->numEntries;
+    hPtr = Tcl_FirstHashEntry(hash, &search);
+    while (hPtr != NULL) {
+	ensemblePtr->subcommandArrayPtr[i++] = Tcl_GetHashKey(hash, hPtr);
+	hPtr = Tcl_NextHashEntry(&search);
+	if (hPtr == NULL) {
+	    break;
+	}
+	ensemblePtr->subcommandArrayPtr[--j] = Tcl_GetHashKey(hash, hPtr);
+	hPtr = Tcl_NextHashEntry(&search);
+    }
+    if (hash->numEntries > 1) {
+	qsort(ensemblePtr->subcommandArrayPtr, (unsigned) hash->numEntries,
+		sizeof(char *), NsEnsembleStringOrder);
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * NsEnsembleStringOrder --
+ *
+ *	Helper function to compare two pointers to two strings for use with
+ *	qsort().
+ *
+ * Results:
+ *	-1 if the first string is smaller, 1 if the second string is smaller,
+ *	and 0 if they are equal.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+NsEnsembleStringOrder(
+    const void *strPtr1,
+    const void *strPtr2)
+{
+    return strcmp(*(const char **)strPtr1, *(const char **)strPtr2);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * FreeEnsembleCmdRep --
+ *
+ *	Destroys the internal representation of a Tcl_Obj that has been
+ *	holding information about a command in an ensemble.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Memory is deallocated. If this held the last reference to a
+ *	namespace's main structure, that main structure will also be
+ *	destroyed.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+FreeEnsembleCmdRep(
+    Tcl_Obj *objPtr)
+{
+    EnsembleCmdRep *ensembleCmd = objPtr->internalRep.otherValuePtr;
+
+    Tcl_DecrRefCount(ensembleCmd->realPrefixObj);
+    ckfree(ensembleCmd->fullSubcmdName);
+    TclNsDecrRefCount(ensembleCmd->nsPtr);
+    ckfree((char *) ensembleCmd);
+    objPtr->typePtr = NULL;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * DupEnsembleCmdRep --
+ *
+ *	Makes one Tcl_Obj into a copy of another that is a subcommand of an
+ *	ensemble.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Memory is allocated, and the namespace that the ensemble is built on
+ *	top of gains another reference.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+DupEnsembleCmdRep(
+    Tcl_Obj *objPtr,
+    Tcl_Obj *copyPtr)
+{
+    EnsembleCmdRep *ensembleCmd = objPtr->internalRep.otherValuePtr;
+    EnsembleCmdRep *ensembleCopy = (EnsembleCmdRep *)
+	    ckalloc(sizeof(EnsembleCmdRep));
+    int length = strlen(ensembleCmd->fullSubcmdName);
+
+    copyPtr->typePtr = &tclEnsembleCmdType;
+    copyPtr->internalRep.otherValuePtr = ensembleCopy;
+    ensembleCopy->nsPtr = ensembleCmd->nsPtr;
+    ensembleCopy->epoch = ensembleCmd->epoch;
+    ensembleCopy->token = ensembleCmd->token;
+    ensembleCopy->nsPtr->refCount++;
+    ensembleCopy->realPrefixObj = ensembleCmd->realPrefixObj;
+    Tcl_IncrRefCount(ensembleCopy->realPrefixObj);
+    ensembleCopy->fullSubcmdName = ckalloc((unsigned) length+1);
+    memcpy(ensembleCopy->fullSubcmdName, ensembleCmd->fullSubcmdName,
+	    (unsigned) length+1);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * StringOfEnsembleCmdRep --
+ *
+ *	Creates a string representation of a Tcl_Obj that holds a subcommand
+ *	of an ensemble.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The object gains a string (UTF-8) representation.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+StringOfEnsembleCmdRep(
+    Tcl_Obj *objPtr)
+{
+    EnsembleCmdRep *ensembleCmd = objPtr->internalRep.otherValuePtr;
+    int length = strlen(ensembleCmd->fullSubcmdName);
+
+    objPtr->length = length;
+    objPtr->bytes = ckalloc((unsigned) length+1);
+    memcpy(objPtr->bytes, ensembleCmd->fullSubcmdName, (unsigned) length+1);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclCompileEnsemble --
+ *
+ *	Procedure called to compile an ensemble command. Note that most
+ *	ensembles are not compiled, since modifying a compiled ensemble causes
+ *	a invalidation of all existing bytecode (expensive!) which is not
+ *	normally warranted.
+ *
+ * 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 subcommands of the
+ *	ensemble at runtime if a compile-time mapping is possible.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+TclCompileEnsemble(
+    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;
+    Tcl_Obj *mapObj, *subcmdObj, *targetCmdObj, *listObj, **elems;
+    Tcl_Command ensemble = (Tcl_Command) cmdPtr;
+    Tcl_Parse synthetic;
+    int len, numBytes, result, flags = 0, i;
+    const char *word;
+
+    if (parsePtr->numWords < 2) {
+	return TCL_ERROR;
+    }
+
+    tokenPtr = TokenAfter(parsePtr->tokenPtr);
+    if (tokenPtr->type != TCL_TOKEN_SIMPLE_WORD) {
+	/*
+	 * Too hard.
+	 */
+
+	return TCL_ERROR;
+    }
+
+    word = tokenPtr[1].start;
+    numBytes = tokenPtr[1].size;
+
+    /*
+     * There's a sporting chance we'll be able to compile this. But now we
+     * must check properly. To do that, check that we're compiling an ensemble
+     * that has a compilable command as its appropriate subcommand.
+     */
+
+    if (Tcl_GetEnsembleMappingDict(NULL, ensemble, &mapObj) != TCL_OK
+	    || mapObj == NULL) {
+	/*
+	 * Either not an ensemble or a mapping isn't installed. Crud. Too hard
+	 * to proceed.
+	 */
+
+	return TCL_ERROR;
+    }
+
+    /*
+     * Also refuse to compile anything that uses a formal parameter list for
+     * now, on the grounds that it is too complex.
+     */
+
+    if (Tcl_GetEnsembleParameterList(NULL, ensemble, &listObj) != TCL_OK
+	    || listObj != NULL) {
+	/*
+	 * Figuring out how to compile this has become too much. Bail out.
+	 */
+
+	return TCL_ERROR;
+    }
+
+    /*
+     * Next, get the flags. We need them on several code paths.
+     */
+
+    (void) Tcl_GetEnsembleFlags(NULL, ensemble, &flags);
+
+    /*
+     * Check to see if there's also a subcommand list; must check to see if
+     * the subcommand we are calling is in that list if it exists, since that
+     * list filters the entries in the map.
+     */
+
+    (void) Tcl_GetEnsembleSubcommandList(NULL, ensemble, &listObj);
+    if (listObj != NULL) {
+	int sclen;
+	const char *str;
+	Tcl_Obj *matchObj = NULL;
+
+	if (Tcl_ListObjGetElements(NULL, listObj, &len, &elems) != TCL_OK) {
+	    return TCL_ERROR;
+	}
+	for (i=0 ; i<len ; i++) {
+	    str = Tcl_GetStringFromObj(elems[i], &sclen);
+	    if (sclen==numBytes && !memcmp(word, str, (unsigned) numBytes)) {
+		/*
+		 * Exact match! Excellent!
+		 */
+
+		result = Tcl_DictObjGet(NULL, mapObj,elems[i], &targetCmdObj);
+		if (result != TCL_OK || targetCmdObj == NULL) {
+		    return TCL_ERROR;
+		}
+		goto doneMapLookup;
+	    }
+
+	    /*
+	     * Check to see if we've got a prefix match. A single prefix match
+	     * is fine, and allows us to refine our dictionary lookup, but
+	     * multiple prefix matches is a Bad Thing and will prevent us from
+	     * making progress. Note that we cannot do the lookup immediately
+	     * in the prefix case; might be another entry later in the list
+	     * that causes things to fail.
+	     */
+
+	    if ((flags & TCL_ENSEMBLE_PREFIX)
+		    && strncmp(word, str, (unsigned) numBytes) == 0) {
+		if (matchObj != NULL) {
+		    return TCL_ERROR;
+		}
+		matchObj = elems[i];
+	    }
+	}
+	if (matchObj != NULL) {
+	    result = Tcl_DictObjGet(NULL, mapObj, matchObj, &targetCmdObj);
+	    if (result != TCL_OK || targetCmdObj == NULL) {
+		return TCL_ERROR;
+	    }
+	    goto doneMapLookup;
+	}
+	return TCL_ERROR;
+    } else {
+	/*
+	 * No map, so check the dictionary directly.
+	 */
+
+	TclNewStringObj(subcmdObj, word, numBytes);
+	result = Tcl_DictObjGet(NULL, mapObj, subcmdObj, &targetCmdObj);
+	TclDecrRefCount(subcmdObj);
+	if (result == TCL_OK && targetCmdObj != NULL) {
+	    /*
+	     * Got it. Skip the fiddling around with prefixes.
+	     */
+
+	    goto doneMapLookup;
+	}
+
+	/*
+	 * We've not literally got a valid subcommand. But maybe we have a
+	 * prefix. Check if prefix matches are allowed.
+	 */
+
+	if (flags & TCL_ENSEMBLE_PREFIX) {
+	    Tcl_DictSearch s;
+	    int done, matched;
+	    Tcl_Obj *tmpObj;
+
+	    /*
+	     * Iterate over the keys in the dictionary, checking to see if
+	     * we're a prefix.
+	     */
+
+	    Tcl_DictObjFirst(NULL,mapObj,&s,&subcmdObj,&tmpObj,&done);
+	    matched = 0;
+	    while (!done) {
+		if (strncmp(TclGetString(subcmdObj), word,
+			(unsigned) numBytes) == 0) {
+		    if (matched++) {
+			/*
+			 * Must have matched twice! Not unique, so no point
+			 * looking further.
+			 */
+
+			break;
+		    }
+		    targetCmdObj = tmpObj;
+		}
+		Tcl_DictObjNext(&s, &subcmdObj, &tmpObj, &done);
+	    }
+	    Tcl_DictObjDone(&s);
+
+	    /*
+	     * If we have anything other than a single match, we've failed the
+	     * unique prefix check.
+	     */
+
+	    if (matched != 1) {
+		return TCL_ERROR;
+	    }
+	} else {
+	    return TCL_ERROR;
+	}
+    }
+
+    /*
+     * OK, we definitely map to something. But what?
+     *
+     * The command we map to is the first word out of the map element. Note
+     * that we also reject dealing with multi-element rewrites if we are in a
+     * safe interpreter, as there is otherwise a (highly gnarly!) way to make
+     * Tcl crash open to exploit.
+     */
+
+  doneMapLookup:
+    if (Tcl_ListObjGetElements(NULL, targetCmdObj, &len, &elems) != TCL_OK) {
+	return TCL_ERROR;
+    }
+    if (len > 1 && Tcl_IsSafe(interp)) {
+	return TCL_ERROR;
+    }
+    targetCmdObj = elems[0];
+
+    Tcl_IncrRefCount(targetCmdObj);
+    cmdPtr = (Command *) Tcl_GetCommandFromObj(interp, targetCmdObj);
+    TclDecrRefCount(targetCmdObj);
+    if (cmdPtr == NULL || cmdPtr->compileProc == NULL) {
+	/*
+	 * Maps to an undefined command or a command without a compiler.
+	 * Cannot compile.
+	 */
+
+	return TCL_ERROR;
+    }
+
+    /*
+     * Now we've done the mapping process, can now actually try to compile.
+     * We do this by handing off to the subcommand's actual compiler. But to
+     * do that, we have to perform some trickery to rewrite the arguments.
+     */
+
+    TclParseInit(interp, NULL, 0, &synthetic);
+    synthetic.numWords = parsePtr->numWords - 2 + len;
+    TclGrowParseTokenArray(&synthetic, 2*len);
+    synthetic.numTokens = 2*len;
+
+    /*
+     * Now we have the space to work in, install something rewritten. Note
+     * that we are here praying for all our might that none of these words are
+     * a script; the error detection code will crash if that happens and there
+     * is nothing we can do to avoid it!
+     */
+
+    for (i=0 ; i<len ; i++) {
+	int sclen;
+	const char *str = Tcl_GetStringFromObj(elems[i], &sclen);
+
+	synthetic.tokenPtr[2*i].type = TCL_TOKEN_SIMPLE_WORD;
+	synthetic.tokenPtr[2*i].start = str;
+	synthetic.tokenPtr[2*i].size = sclen;
+	synthetic.tokenPtr[2*i].numComponents = 1;
+
+	synthetic.tokenPtr[2*i+1].type = TCL_TOKEN_TEXT;
+	synthetic.tokenPtr[2*i+1].start = str;
+	synthetic.tokenPtr[2*i+1].size = sclen;
+	synthetic.tokenPtr[2*i+1].numComponents = 0;
+    }
+
+    /*
+     * Copy over the real argument tokens.
+     */
+
+    for (i=len; i<synthetic.numWords; i++) {
+	int toCopy;
+
+	tokenPtr = TokenAfter(tokenPtr);
+	toCopy = tokenPtr->numComponents + 1;
+	TclGrowParseTokenArray(&synthetic, toCopy);
+	memcpy(synthetic.tokenPtr + synthetic.numTokens, tokenPtr,
+		sizeof(Tcl_Token) * toCopy);
+	synthetic.numTokens += toCopy;
+    }
+
+    /*
+     * Hand off compilation to the subcommand compiler. At last!
+     */
+
+    result = cmdPtr->compileProc(interp, &synthetic, cmdPtr, envPtr);
+
+    /*
+     * Clean up if necessary.
+     */
+
+    Tcl_FreeParse(&synthetic);
+    return result;
+}
+
+/*
+ * Local Variables:
+ * mode: c
+ * c-basic-offset: 4
+ * fill-column: 78
+ * End:
+ */
diff --git a/generic/tclInt.h b/generic/tclInt.h
index bccb5a8..f66fa33 100644
--- a/generic/tclInt.h
+++ b/generic/tclInt.h
@@ -15,7 +15,7 @@
  * See the file "license.terms" for information on usage and redistribution of
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclInt.h,v 1.460 2010/02/09 20:51:54 dkf Exp $
+ * RCS: @(#) $Id: tclInt.h,v 1.461 2010/02/13 18:11:06 dkf Exp $
  */
 
 #ifndef _TCLINT
@@ -423,10 +423,91 @@ typedef struct {
 } EnsembleCmdRep;
 
 /*
- * Flag to enable bytecode compilation of an ensemble.
+ * The client data for an ensemble command. This consists of the table of
+ * commands that are actually exported by the namespace, and an epoch counter
+ * that, combined with the exportLookupEpoch field of the namespace structure,
+ * defines whether the table contains valid data or will need to be recomputed
+ * next time the ensemble command is called.
+ */
+
+typedef struct EnsembleConfig {
+    Namespace *nsPtr;		/* The namspace backing this ensemble up. */
+    Tcl_Command token;		/* The token for the command that provides
+				 * ensemble support for the namespace, or NULL
+				 * if the command has been deleted (or never
+				 * existed; the global namespace never has an
+				 * ensemble command.) */
+    int epoch;			/* The epoch at which this ensemble's table of
+				 * exported commands is valid. */
+    char **subcommandArrayPtr;	/* Array of ensemble subcommand names. At all
+				 * consistent points, this will have the same
+				 * number of entries as there are entries in
+				 * the subcommandTable hash. */
+    Tcl_HashTable subcommandTable;
+				/* Hash table of ensemble subcommand names,
+				 * which are its keys so this also provides
+				 * the storage management for those subcommand
+				 * names. The contents of the entry values are
+				 * object version the prefix lists to use when
+				 * substituting for the command/subcommand to
+				 * build the ensemble implementation command.
+				 * Has to be stored here as well as in
+				 * subcommandDict because that field is NULL
+				 * when we are deriving the ensemble from the
+				 * namespace exports list. FUTURE WORK: use
+				 * object hash table here. */
+    struct EnsembleConfig *next;/* The next ensemble in the linked list of
+				 * ensembles associated with a namespace. If
+				 * this field points to this ensemble, the
+				 * structure has already been unlinked from
+				 * all lists, and cannot be found by scanning
+				 * the list from the namespace's ensemble
+				 * field. */
+    int flags;			/* ORed combo of TCL_ENSEMBLE_PREFIX,
+				 * ENSEMBLE_DEAD and ENSEMBLE_COMPILE. */
+
+    /* OBJECT FIELDS FOR ENSEMBLE CONFIGURATION */
+
+    Tcl_Obj *subcommandDict;	/* Dictionary providing mapping from
+				 * subcommands to their implementing command
+				 * prefixes, or NULL if we are to build the
+				 * map automatically from the namespace
+				 * exports. */
+    Tcl_Obj *subcmdList;	/* List of commands that this ensemble
+				 * actually provides, and whose implementation
+				 * will be built using the subcommandDict (if
+				 * present and defined) and by simple mapping
+				 * to the namespace otherwise. If NULL,
+				 * indicates that we are using the (dynamic)
+				 * list of currently exported commands. */
+    Tcl_Obj *unknownHandler;	/* Script prefix used to handle the case when
+				 * no match is found (according to the rule
+				 * defined by flag bit TCL_ENSEMBLE_PREFIX) or
+				 * NULL to use the default error-generating
+				 * behaviour. The script execution gets all
+				 * the arguments to the ensemble command
+				 * (including objv[0]) and will have the
+				 * results passed directly back to the caller
+				 * (including the error code) unless the code
+				 * is TCL_CONTINUE in which case the
+				 * subcommand will be reparsed by the ensemble
+				 * core, presumably because the ensemble
+				 * itself has been updated. */
+    Tcl_Obj *parameterList;	/* List of ensemble parameter names. */
+    int numParameters;		/* Cached number of parameters. This is either
+				 * 0 (if the parameterList field is NULL) or
+				 * the length of the list in the parameterList
+				 * field. */
+} EnsembleConfig;
+
+/*
+ * Various bits for the EnsembleConfig.flags field.
  */
 
-#define ENSEMBLE_COMPILE 0x4
+#define ENSEMBLE_DEAD	0x1	/* Flag value to say that the ensemble is dead
+				 * and on its way out. */
+#define ENSEMBLE_COMPILE 0x4	/* Flag to enable bytecode compilation of an
+				 * ensemble. */
 
 /*
  *----------------------------------------------------------------
@@ -2859,6 +2940,7 @@ MODULE_SCOPE int	TclMergeReturnOptions(Tcl_Interp *interp, int objc,
 			    Tcl_Obj *const objv[], Tcl_Obj **optionsPtrPtr,
 			    int *codePtr, int *levelPtr);
 MODULE_SCOPE int	TclNokia770Doubles();
+MODULE_SCOPE void	TclNsDecrRefCount(Namespace *nsPtr);
 MODULE_SCOPE void	TclObjVarErrMsg(Tcl_Interp *interp, Tcl_Obj *part1Ptr,
 			    Tcl_Obj *part2Ptr, const char *operation,
 			    const char *reason, int index);
@@ -3178,6 +3260,9 @@ MODULE_SCOPE int	Tcl_LsortObjCmd(ClientData clientData,
 MODULE_SCOPE int	Tcl_NamespaceObjCmd(ClientData clientData,
 			    Tcl_Interp *interp, int objc,
 			    Tcl_Obj *const objv[]);
+MODULE_SCOPE int	TclNamespaceEnsembleCmd(ClientData dummy,
+			    Tcl_Interp *interp, int objc,
+			    Tcl_Obj *const objv[]);
 MODULE_SCOPE int	Tcl_OpenObjCmd(ClientData clientData,
 			    Tcl_Interp *interp, int objc,
 			    Tcl_Obj *const objv[]);
diff --git a/generic/tclNamesp.c b/generic/tclNamesp.c
index f8ee460..fbbab98 100644
--- a/generic/tclNamesp.c
+++ b/generic/tclNamesp.c
@@ -23,7 +23,7 @@
  * See the file "license.terms" for information on usage and redistribution of
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclNamesp.c,v 1.199 2010/01/03 20:29:11 msofer Exp $
+ * RCS: @(#) $Id: tclNamesp.c,v 1.200 2010/02/13 18:11:06 dkf Exp $
  */
 
 #include "tclInt.h"
@@ -70,87 +70,6 @@ typedef struct ResolvedNsName {
 } ResolvedNsName;
 
 /*
- * The client data for an ensemble command. This consists of the table of
- * commands that are actually exported by the namespace, and an epoch counter
- * that, combined with the exportLookupEpoch field of the namespace structure,
- * defines whether the table contains valid data or will need to be recomputed
- * next time the ensemble command is called.
- */
-
-typedef struct EnsembleConfig {
-    Namespace *nsPtr;		/* The namspace backing this ensemble up. */
-    Tcl_Command token;		/* The token for the command that provides
-				 * ensemble support for the namespace, or NULL
-				 * if the command has been deleted (or never
-				 * existed; the global namespace never has an
-				 * ensemble command.) */
-    int epoch;			/* The epoch at which this ensemble's table of
-				 * exported commands is valid. */
-    char **subcommandArrayPtr;	/* Array of ensemble subcommand names. At all
-				 * consistent points, this will have the same
-				 * number of entries as there are entries in
-				 * the subcommandTable hash. */
-    Tcl_HashTable subcommandTable;
-				/* Hash table of ensemble subcommand names,
-				 * which are its keys so this also provides
-				 * the storage management for those subcommand
-				 * names. The contents of the entry values are
-				 * object version the prefix lists to use when
-				 * substituting for the command/subcommand to
-				 * build the ensemble implementation command.
-				 * Has to be stored here as well as in
-				 * subcommandDict because that field is NULL
-				 * when we are deriving the ensemble from the
-				 * namespace exports list. FUTURE WORK: use
-				 * object hash table here. */
-    struct EnsembleConfig *next;/* The next ensemble in the linked list of
-				 * ensembles associated with a namespace. If
-				 * this field points to this ensemble, the
-				 * structure has already been unlinked from
-				 * all lists, and cannot be found by scanning
-				 * the list from the namespace's ensemble
-				 * field. */
-    int flags;			/* ORed combo of TCL_ENSEMBLE_PREFIX, ENS_DEAD
-				 * and ENSEMBLE_COMPILE. */
-
-    /* OBJECT FIELDS FOR ENSEMBLE CONFIGURATION */
-
-    Tcl_Obj *subcommandDict;	/* Dictionary providing mapping from
-				 * subcommands to their implementing command
-				 * prefixes, or NULL if we are to build the
-				 * map automatically from the namespace
-				 * exports. */
-    Tcl_Obj *subcmdList;	/* List of commands that this ensemble
-				 * actually provides, and whose implementation
-				 * will be built using the subcommandDict (if
-				 * present and defined) and by simple mapping
-				 * to the namespace otherwise. If NULL,
-				 * indicates that we are using the (dynamic)
-				 * list of currently exported commands. */
-    Tcl_Obj *unknownHandler;	/* Script prefix used to handle the case when
-				 * no match is found (according to the rule
-				 * defined by flag bit TCL_ENSEMBLE_PREFIX) or
-				 * NULL to use the default error-generating
-				 * behaviour. The script execution gets all
-				 * the arguments to the ensemble command
-				 * (including objv[0]) and will have the
-				 * results passed directly back to the caller
-				 * (including the error code) unless the code
-				 * is TCL_CONTINUE in which case the
-				 * subcommand will be reparsed by the ensemble
-				 * core, presumably because the ensemble
-				 * itself has been updated. */
-    Tcl_Obj *parameterList;	/* List of ensemble parameter names. */
-    int numParameters;		/* Cached number of parameters. This is either
-				 * 0 (if the parameterList field is NULL) or
-				 * the length of the list in the parameterList
-				 * field. */
-} EnsembleConfig;
-
-#define ENS_DEAD	0x1	/* Flag value to say that the ensemble is dead
-				 * and on its way out. */
-
-/*
  * Declarations for functions local to this file:
  */
 
@@ -160,9 +79,6 @@ static int		DoImport(Tcl_Interp *interp,
 			    const char *cmdName, const char *pattern,
 			    Namespace *importNsPtr, int allowOverwrite);
 static void		DupNsNameInternalRep(Tcl_Obj *objPtr,Tcl_Obj *copyPtr);
-static inline int	EnsembleUnknownCallback(Tcl_Interp *interp,
-			    EnsembleConfig *ensemblePtr, int objc,
-			    Tcl_Obj *const objv[], Tcl_Obj **prefixObjPtr);
 static char *		ErrorCodeRead(ClientData clientData,Tcl_Interp *interp,
 			    const char *name1, const char *name2, int flags);
 static char *		ErrorInfoRead(ClientData clientData,Tcl_Interp *interp,
@@ -188,8 +104,6 @@ static int		NamespaceCurrentCmd(ClientData dummy,
 			    Tcl_Interp *interp,int objc,Tcl_Obj *const objv[]);
 static int		NamespaceDeleteCmd(ClientData dummy,Tcl_Interp *interp,
 			    int objc, Tcl_Obj *const objv[]);
-static int		NamespaceEnsembleCmd(ClientData dummy,
-			    Tcl_Interp *interp,int objc,Tcl_Obj *const objv[]);
 static int		NamespaceEvalCmd(ClientData dummy, Tcl_Interp *interp,
 			    int objc, Tcl_Obj *const objv[]);
 static int		NamespaceExistsCmd(ClientData dummy,Tcl_Interp *interp,
@@ -221,20 +135,6 @@ static int		NamespaceUnknownCmd(ClientData dummy,
 static int		NamespaceWhichCmd(ClientData dummy, Tcl_Interp *interp,
 			    int objc, Tcl_Obj *const objv[]);
 static int		SetNsNameFromAny(Tcl_Interp *interp, Tcl_Obj *objPtr);
-static int		NsEnsembleImplementationCmd(ClientData clientData,
-			    Tcl_Interp *interp,int objc,Tcl_Obj *const objv[]);
-static int		NsEnsembleImplementationCmdNR(ClientData clientData,
-			    Tcl_Interp *interp,int objc,Tcl_Obj *const objv[]);
-static void		BuildEnsembleConfig(EnsembleConfig *ensemblePtr);
-static int		NsEnsembleStringOrder(const void *strPtr1,
-			    const void *strPtr2);
-static void		DeleteEnsembleConfig(ClientData clientData);
-static void		MakeCachedEnsembleCommand(Tcl_Obj *objPtr,
-			    EnsembleConfig *ensemblePtr,
-			    const char *subcmdName, Tcl_Obj *prefixObjPtr);
-static void		FreeEnsembleCmdRep(Tcl_Obj *objPtr);
-static void		DupEnsembleCmdRep(Tcl_Obj *objPtr, Tcl_Obj *copyPtr);
-static void		StringOfEnsembleCmdRep(Tcl_Obj *objPtr);
 static void		UnlinkNsPath(Namespace *nsPtr);
 
 static Tcl_NRPostProc NsEval_Callback;
@@ -253,21 +153,6 @@ static const Tcl_ObjType nsNameType = {
     NULL,			/* updateStringProc */
     SetNsNameFromAny		/* setFromAnyProc */
 };
-
-/*
- * This structure defines a Tcl object type that contains a reference to an
- * ensemble subcommand (e.g. the "length" in [string length ab]). It is used
- * to cache the mapping between the subcommand itself and the real command
- * that implements it.
- */
-
-const Tcl_ObjType tclEnsembleCmdType = {
-    "ensembleCommand",		/* the type's name */
-    FreeEnsembleCmdRep,		/* freeIntRepProc */
-    DupEnsembleCmdRep,		/* dupIntRepProc */
-    StringOfEnsembleCmdRep,	/* updateStringProc */
-    NULL			/* setFromAnyProc */
-};
 
 /*
  *----------------------------------------------------------------------
@@ -430,7 +315,7 @@ Tcl_PushCallFrame(
     framePtr->clientData = NULL;
     framePtr->localCachePtr = NULL;
     framePtr->tailcallPtr = NULL;
-    
+
     /*
      * Push the new call frame onto the interpreter's stack of procedure call
      * frames making it the current frame.
@@ -556,7 +441,7 @@ void
 TclPopStackFrame(
     Tcl_Interp *interp)		/* Interpreter with call frame to pop. */
 {
-    CallFrame *freePtr = ((Interp *)interp)->framePtr;
+    CallFrame *freePtr = ((Interp *) interp)->framePtr;
 
     Tcl_PopCallFrame(interp);
     TclStackFree(interp, freePtr);
@@ -619,7 +504,7 @@ ErrorCodeRead(
     const char *name2,
     int flags)
 {
-    Interp *iPtr = (Interp *)interp;
+    Interp *iPtr = (Interp *) interp;
 
     if (Tcl_InterpDeleted(interp) || !(iPtr->flags & ERR_LEGACY_COPY)) {
 	return NULL;
@@ -852,7 +737,7 @@ Tcl_CreateNamespace(
 
     if (parentPtr != NULL) {
 	entryPtr = Tcl_CreateHashEntry(
-		TclGetNamespaceChildTable((Tcl_Namespace *)parentPtr),
+		TclGetNamespaceChildTable((Tcl_Namespace *) parentPtr),
 		simpleName, &newEntry);
 	Tcl_SetHashValue(entryPtr, nsPtr);
     } else {
@@ -973,14 +858,14 @@ Tcl_DeleteNamespace(
 	    entryPtr != NULL;) {
 	cmdPtr = (Command *) Tcl_GetHashValue(entryPtr);
 	if (cmdPtr->nreProc == NRInterpCoroutine) {
-	    Tcl_DeleteCommandFromToken((Tcl_Interp *) iPtr, (Tcl_Command)cmdPtr);
-	    entryPtr = Tcl_FirstHashEntry(&nsPtr->cmdTable, &search);	    
+	    Tcl_DeleteCommandFromToken((Tcl_Interp *) iPtr,
+		    (Tcl_Command) cmdPtr);
+	    entryPtr = Tcl_FirstHashEntry(&nsPtr->cmdTable, &search);
 	} else {
 	    entryPtr = entryPtr->nextPtr;
 	}
-    }    
-    
-    
+    }
+
     /*
      * If the namespace has associated ensemble commands, delete them first.
      * This leaves the actual contents of the namespace alone (unless they are
@@ -1183,6 +1068,7 @@ TclTeardownNamespace(
     }
     if (nsPtr->commandPathSourceList != NULL) {
 	NamespacePathEntry *nsPathPtr = nsPtr->commandPathSourceList;
+
 	do {
 	    if (nsPathPtr->nsPtr != NULL && nsPathPtr->creatorNsPtr != NULL) {
 		nsPathPtr->creatorNsPtr->cmdRefEpoch++;
@@ -1290,6 +1176,33 @@ NamespaceFree(
 /*
  *----------------------------------------------------------------------
  *
+ * TclNsDecrRefCount --
+ *
+ *	Drops a reference to a namespace and frees it if the namespace has
+ *	been deleted and the last reference has just been dropped.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TclNsDecrRefCount(
+    Namespace *nsPtr)
+{
+    nsPtr->refCount--;
+    if ((nsPtr->refCount == 0) && (nsPtr->flags & NS_DEAD)) {
+	NamespaceFree(nsPtr);
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
  * Tcl_Export --
  *
  *	Makes all the commands matching a pattern available to later be
@@ -1616,6 +1529,7 @@ Tcl_Import(
     for (hPtr = Tcl_FirstHashEntry(&importNsPtr->cmdTable, &search);
 	    (hPtr != NULL); hPtr = Tcl_NextHashEntry(&search)) {
 	char *cmdName = Tcl_GetHashKey(&importNsPtr->cmdTable, hPtr);
+
 	if (Tcl_StringMatch(cmdName, simplePattern) &&
 		DoImport(interp, nsPtr, hPtr, cmdName, pattern, importNsPtr,
 		allowOverwrite) == TCL_ERROR) {
@@ -1834,13 +1748,13 @@ Tcl_ForgetImport(
 	 */
 
 	if (TclMatchIsTrivial(simplePattern)) {
-	    Command *cmdPtr;
-
 	    hPtr = Tcl_FindHashEntry(&nsPtr->cmdTable, simplePattern);
-	    if ((hPtr != NULL)
-		    && (cmdPtr = Tcl_GetHashValue(hPtr))
-		    && (cmdPtr->deleteProc == DeleteImportedCmd)) {
-		Tcl_DeleteCommandFromToken(interp, (Tcl_Command) cmdPtr);
+	    if (hPtr != NULL) {
+		Command *cmdPtr = Tcl_GetHashValue(hPtr);
+
+		if (cmdPtr && (cmdPtr->deleteProc == DeleteImportedCmd)) {
+		    Tcl_DeleteCommandFromToken(interp, (Tcl_Command) cmdPtr);
+		}
 	    }
 	    return TCL_OK;
 	}
@@ -1970,7 +1884,7 @@ InvokeImportedNRCmd(
     ImportedCmdData *dataPtr = clientData;
     Command *realCmdPtr = dataPtr->realCmdPtr;
 
-    ((Interp *)interp)->evalFlags |= TCL_EVAL_REDIRECT;
+    ((Interp *) interp)->evalFlags |= TCL_EVAL_REDIRECT;
     return Tcl_NRCmdSwap(interp, (Tcl_Command) realCmdPtr, objc, objv, 0);
 }
 
@@ -2424,7 +2338,9 @@ Tcl_FindNamespace(
 
     if (nsPtr != NULL) {
 	return (Tcl_Namespace *) nsPtr;
-    } else if (flags & TCL_LEAVE_ERR_MSG) {
+    }
+
+    if (flags & TCL_LEAVE_ERR_MSG) {
 	Tcl_ResetResult(interp);
 	Tcl_AppendResult(interp, "unknown namespace \"", name, "\"", NULL);
 	Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "NAMESPACE", name, NULL);
@@ -2739,7 +2655,7 @@ TclResetShadowedCmdRefs(
 		 * for a fresh compilation of every bytecode.
 		 */
 
-		if (((Command *)Tcl_GetHashValue(hPtr))->compileProc != NULL) {
+		if (((Command *)Tcl_GetHashValue(hPtr))->compileProc != NULL){
 		    nsPtr->resolverEpoch++;
 		}
 	    }
@@ -2753,6 +2669,7 @@ TclResetShadowedCmdRefs(
 	trailFront++;
 	if (trailFront == trailSize) {
 	    int newSize = 2 * trailSize;
+
 	    trailPtr = (Namespace **) TclStackRealloc(interp,
 		    trailPtr, newSize * sizeof(Namespace *));
 	    trailSize = newSize;
@@ -2917,7 +2834,7 @@ TclNRNamespaceObjCmd(
 	NSInscopeIdx, NSOriginIdx, NSParentIdx, NSPathIdx, NSQualifiersIdx,
 	NSTailIdx, NSUnknownIdx, NSUpvarIdx, NSWhichIdx
     };
-    int index, result;
+    int index;
 
     if (objc < 2) {
 	Tcl_WrongNumArgs(interp, 1, objv, "subcommand ?arg ...?");
@@ -2928,72 +2845,54 @@ TclNRNamespaceObjCmd(
      * Return an index reflecting the particular subcommand.
      */
 
-    result = Tcl_GetIndexFromObj((Tcl_Interp *) interp, objv[1], subCmds,
-	    "option", /*flags*/ 0, (int *) &index);
-    if (result != TCL_OK) {
-	return result;
+    if (Tcl_GetIndexFromObj(interp, objv[1], subCmds, "option", /*flags*/ 0,
+	    (int *) &index) != TCL_OK) {
+	return TCL_ERROR;
     }
 
     switch (index) {
     case NSChildrenIdx:
-	result = NamespaceChildrenCmd(clientData, interp, objc, objv);
-	break;
+	return NamespaceChildrenCmd(clientData, interp, objc, objv);
     case NSCodeIdx:
-	result = NamespaceCodeCmd(clientData, interp, objc, objv);
-	break;
+	return NamespaceCodeCmd(clientData, interp, objc, objv);
     case NSCurrentIdx:
-	result = NamespaceCurrentCmd(clientData, interp, objc, objv);
-	break;
+	return NamespaceCurrentCmd(clientData, interp, objc, objv);
     case NSDeleteIdx:
-	result = NamespaceDeleteCmd(clientData, interp, objc, objv);
-	break;
+	return NamespaceDeleteCmd(clientData, interp, objc, objv);
     case NSEnsembleIdx:
-	result = NamespaceEnsembleCmd(clientData, interp, objc, objv);
-	break;
+	return TclNamespaceEnsembleCmd(clientData, interp, objc, objv);
     case NSEvalIdx:
-	result = NamespaceEvalCmd(clientData, interp, objc, objv);
-	break;
+	return NamespaceEvalCmd(clientData, interp, objc, objv);
     case NSExistsIdx:
-	result = NamespaceExistsCmd(clientData, interp, objc, objv);
-	break;
+	return NamespaceExistsCmd(clientData, interp, objc, objv);
     case NSExportIdx:
-	result = NamespaceExportCmd(clientData, interp, objc, objv);
-	break;
+	return NamespaceExportCmd(clientData, interp, objc, objv);
     case NSForgetIdx:
-	result = NamespaceForgetCmd(clientData, interp, objc, objv);
-	break;
+	return NamespaceForgetCmd(clientData, interp, objc, objv);
     case NSImportIdx:
-	result = NamespaceImportCmd(clientData, interp, objc, objv);
-	break;
+	return NamespaceImportCmd(clientData, interp, objc, objv);
     case NSInscopeIdx:
-	result = NamespaceInscopeCmd(clientData, interp, objc, objv);
-	break;
+	return NamespaceInscopeCmd(clientData, interp, objc, objv);
     case NSOriginIdx:
-	result = NamespaceOriginCmd(clientData, interp, objc, objv);
-	break;
+	return NamespaceOriginCmd(clientData, interp, objc, objv);
     case NSParentIdx:
-	result = NamespaceParentCmd(clientData, interp, objc, objv);
-	break;
+	return NamespaceParentCmd(clientData, interp, objc, objv);
     case NSPathIdx:
-	result = NamespacePathCmd(clientData, interp, objc, objv);
-	break;
+	return NamespacePathCmd(clientData, interp, objc, objv);
     case NSQualifiersIdx:
-	result = NamespaceQualifiersCmd(clientData, interp, objc, objv);
-	break;
+	return NamespaceQualifiersCmd(clientData, interp, objc, objv);
     case NSTailIdx:
-	result = NamespaceTailCmd(clientData, interp, objc, objv);
-	break;
+	return NamespaceTailCmd(clientData, interp, objc, objv);
     case NSUpvarIdx:
-	result = NamespaceUpvarCmd(clientData, interp, objc, objv);
-	break;
+	return NamespaceUpvarCmd(clientData, interp, objc, objv);
     case NSUnknownIdx:
-	result = NamespaceUnknownCmd(clientData, interp, objc, objv);
-	break;
+	return NamespaceUnknownCmd(clientData, interp, objc, objv);
     case NSWhichIdx:
-	result = NamespaceWhichCmd(clientData, interp, objc, objv);
-	break;
+	return NamespaceWhichCmd(clientData, interp, objc, objv);
+    default:
+	Tcl_Panic("unhandled namespace subcommand");
     }
-    return result;
+    return TCL_ERROR;
 }
 
 /*
@@ -3320,7 +3219,7 @@ NamespaceDeleteCmd(
 	name = TclGetString(objv[i]);
 	namespacePtr = Tcl_FindNamespace(interp, name, NULL, /*flags*/ 0);
 	if ((namespacePtr == NULL)
-		|| (((Namespace *)namespacePtr)->flags & NS_KILLED)) {
+		|| (((Namespace *) namespacePtr)->flags & NS_KILLED)) {
 	    Tcl_AppendResult(interp, "unknown namespace \"",
 		    TclGetString(objv[i]),
 		    "\" in namespace delete command", NULL);
@@ -3379,7 +3278,7 @@ NamespaceEvalCmd(
     Tcl_Obj *const objv[])	/* Argument objects. */
 {
     Interp *iPtr = (Interp *) interp;
-    CmdFrame* invoker;
+    CmdFrame *invoker;
     int word;
     Tcl_Namespace *namespacePtr;
     CallFrame *framePtr, **framePtrPtr;
@@ -3607,6 +3506,7 @@ NamespaceExportCmd(
 	     */
 
 	    Tcl_Obj *listPtr = Tcl_NewListObj(0, NULL);
+
 	    result = Tcl_AppendExportList(interp, (Tcl_Namespace *) currNsPtr,
 		    listPtr);
 	    if (result != TCL_OK) {
@@ -4202,6 +4102,7 @@ UnlinkNsPath(
     int i;
     for (i=0 ; i<nsPtr->commandPathLength ; i++) {
 	NamespacePathEntry *nsPathPtr = &nsPtr->commandPathArray[i];
+
 	if (nsPathPtr->prevPtr != NULL) {
 	    nsPathPtr->prevPtr->nextPtr = nsPathPtr->nextPtr;
 	}
@@ -4242,6 +4143,7 @@ TclInvalidateNsPath(
     Namespace *nsPtr)
 {
     NamespacePathEntry *nsPathPtr = nsPtr->commandPathSourceList;
+
     while (nsPathPtr != NULL) {
 	if (nsPathPtr->nsPtr != NULL) {
 	    nsPathPtr->creatorNsPtr->cmdRefEpoch++;
@@ -4405,10 +4307,10 @@ Tcl_GetNamespaceUnknownHandler(
 				 * exists. */
     Tcl_Namespace *nsPtr)	/* The namespace. */
 {
-    Namespace *currNsPtr = (Namespace *)nsPtr;
+    Namespace *currNsPtr = (Namespace *) nsPtr;
 
     if (currNsPtr->unknownHandlerPtr == NULL &&
-	    currNsPtr == ((Interp *)interp)->globalNsPtr) {
+	    currNsPtr == ((Interp *) interp)->globalNsPtr) {
 	/*
 	 * Default handler for global namespace is "::unknown". For all other
 	 * namespaces, it is NULL (which falls back on the global unknown
@@ -4449,7 +4351,7 @@ Tcl_SetNamespaceUnknownHandler(
     Tcl_Obj *handlerPtr)	/* The new handler, or NULL to reset. */
 {
     int lstlen = 0;
-    Namespace *currNsPtr = (Namespace *)nsPtr;
+    Namespace *currNsPtr = (Namespace *) nsPtr;
 
     /*
      * Ensure that we check for errors *first* before we change anything.
@@ -4601,8 +4503,7 @@ NamespaceUpvarCmd(
     const char *myName;
 
     if (objc < 3 || !(objc & 1)) {
-	Tcl_WrongNumArgs(interp, 2, objv,
-		"ns ?otherVar myVar ...?");
+	Tcl_WrongNumArgs(interp, 2, objv, "ns ?otherVar myVar ...?");
 	return TCL_ERROR;
     }
 
@@ -4615,7 +4516,7 @@ NamespaceUpvarCmd(
 
     for (; objc>0 ; objc-=2, objv+=2) {
 	/*
-	 * Locate the other variable
+	 * Locate the other variable.
 	 */
 
 	savedNsPtr = (Tcl_Namespace *) iPtr->varFramePtr->nsPtr;
@@ -4744,9 +4645,7 @@ FreeNsNameInternalRep(
     register Tcl_Obj *objPtr)	/* nsName object with internal representation
 				 * to free. */
 {
-    register ResolvedNsName *resNamePtr = (ResolvedNsName *)
-	    objPtr->internalRep.twoPtrValue.ptr1;
-    Namespace *nsPtr;
+    ResolvedNsName *resNamePtr = objPtr->internalRep.twoPtrValue.ptr1;
 
     /*
      * Decrement the reference count of the namespace. If there are no more
@@ -4755,18 +4654,13 @@ FreeNsNameInternalRep(
 
     resNamePtr->refCount--;
     if (resNamePtr->refCount == 0) {
-
 	/*
 	 * Decrement the reference count for the cached namespace. If the
 	 * namespace is dead, and there are no more references to it, free
 	 * it.
 	 */
 
-	nsPtr = resNamePtr->nsPtr;
-	nsPtr->refCount--;
-	if ((nsPtr->refCount == 0) && (nsPtr->flags & NS_DEAD)) {
-	    NamespaceFree(nsPtr);
-	}
+	TclNsDecrRefCount(resNamePtr->nsPtr);
 	ckfree((char *) resNamePtr);
     }
     objPtr->typePtr = NULL;
@@ -4796,8 +4690,7 @@ DupNsNameInternalRep(
     Tcl_Obj *srcPtr,		/* Object with internal rep to copy. */
     register Tcl_Obj *copyPtr)	/* Object with internal rep to set. */
 {
-    register ResolvedNsName *resNamePtr = (ResolvedNsName *)
-	    srcPtr->internalRep.twoPtrValue.ptr1;
+    ResolvedNsName *resNamePtr = srcPtr->internalRep.twoPtrValue.ptr1;
 
     copyPtr->internalRep.twoPtrValue.ptr1 = resNamePtr;
     resNamePtr->refCount++;
@@ -4933,2618 +4826,6 @@ TclGetNamespaceChildTable(
 /*
  *----------------------------------------------------------------------
  *
- * NamespaceEnsembleCmd --
- *
- *	Invoked to implement the "namespace ensemble" command that creates and
- *	manipulates ensembles built on top of namespaces. Handles the
- *	following syntax:
- *
- *	    namespace ensemble name ?dictionary?
- *
- * Results:
- *	Returns TCL_OK if successful, and TCL_ERROR if anything goes wrong.
- *
- * Side effects:
- *	Creates the ensemble for the namespace if one did not previously
- *	exist. Alternatively, alters the way that the ensemble's subcommand =>
- *	implementation prefix is configured.
- *
- *----------------------------------------------------------------------
- */
-
-static int
-NamespaceEnsembleCmd(
-    ClientData dummy,
-    Tcl_Interp *interp,
-    int objc,
-    Tcl_Obj *const objv[])
-{
-    Namespace *nsPtr;
-    Tcl_Command token;
-    static const char *const subcommands[] = {
-	"configure", "create", "exists", NULL
-    };
-    enum EnsSubcmds {
-	ENS_CONFIG, ENS_CREATE, ENS_EXISTS
-    };
-    static const char *const createOptions[] = {
-	"-command", "-map", "-parameters", "-prefixes", "-subcommands",
-	"-unknown", NULL
-    };
-    enum EnsCreateOpts {
-	CRT_CMD, CRT_MAP, CRT_PARAM, CRT_PREFIX, CRT_SUBCMDS, CRT_UNKNOWN
-    };
-    static const char *const configOptions[] = {
-	"-map", "-namespace", "-parameters", "-prefixes", "-subcommands",
-	"-unknown", NULL
-    };
-    enum EnsConfigOpts {
-	CONF_MAP, CONF_NAMESPACE, CONF_PARAM, CONF_PREFIX, CONF_SUBCMDS,
-	CONF_UNKNOWN
-    };
-    int index;
-
-    nsPtr = (Namespace *) TclGetCurrentNamespace(interp);
-    if (nsPtr == NULL || nsPtr->flags & NS_DYING) {
-	if (!Tcl_InterpDeleted(interp)) {
-	    Tcl_AppendResult(interp,
-		    "tried to manipulate ensemble of deleted namespace", NULL);
-	}
-	return TCL_ERROR;
-    }
-
-    if (objc < 3) {
-	Tcl_WrongNumArgs(interp, 2, objv, "subcommand ?arg ...?");
-	return TCL_ERROR;
-    }
-    if (Tcl_GetIndexFromObj(interp, objv[2], subcommands, "subcommand", 0,
-	    &index) != TCL_OK) {
-	return TCL_ERROR;
-    }
-
-    switch ((enum EnsSubcmds) index) {
-    case ENS_CREATE: {
-	const char *name;
-	Tcl_DictSearch search;
-	Tcl_Obj *listObj;
-	int done, len, allocatedMapFlag = 0;
-	/*
-	 * Defaults
-	 */
-	Tcl_Obj *subcmdObj = NULL;
-	Tcl_Obj *mapObj = NULL;
-	int permitPrefix = 1;
-	Tcl_Obj *unknownObj = NULL;
-	Tcl_Obj *paramObj = NULL;
-
-	/*
-	 * Check that we've got option-value pairs... [Bug 1558654]
-	 */
-
-	if ((objc & 1) == 0) {
-	    Tcl_WrongNumArgs(interp, 3, objv, "?option value ...?");
-	    return TCL_ERROR;
-	}
-	objv += 3;
-	objc -= 3;
-
-	/*
-	 * Work out what name to use for the command to create. If supplied,
-	 * it is either fully specified or relative to the current namespace.
-	 * If not supplied, it is exactly the name of the current namespace.
-	 */
-
-	name = nsPtr->fullName;
-
-	/*
-	 * Parse the option list, applying type checks as we go. Note that we
-	 * are not incrementing any reference counts in the objects at this
-	 * stage, so the presence of an option multiple times won't cause any
-	 * memory leaks.
-	 */
-
-	for (; objc>1 ; objc-=2,objv+=2) {
-	    if (Tcl_GetIndexFromObj(interp, objv[0], createOptions, "option",
-		    0, &index) != TCL_OK) {
-		if (allocatedMapFlag) {
-		    Tcl_DecrRefCount(mapObj);
-		}
-		return TCL_ERROR;
-	    }
-	    switch ((enum EnsCreateOpts) index) {
-	    case CRT_CMD:
-		name = TclGetString(objv[1]);
-		continue;
-	    case CRT_SUBCMDS:
-		if (TclListObjLength(interp, objv[1], &len) != TCL_OK) {
-		    if (allocatedMapFlag) {
-			Tcl_DecrRefCount(mapObj);
-		    }
-		    return TCL_ERROR;
-		}
-		subcmdObj = (len > 0 ? objv[1] : NULL);
-		continue;
-	    case CRT_PARAM:
-		if (TclListObjLength(interp, objv[1], &len) != TCL_OK) {
-		    if (allocatedMapFlag) {
-			Tcl_DecrRefCount(mapObj);
-		    }
-		    return TCL_ERROR;
-		}
-		paramObj = (len > 0 ? objv[1] : NULL);
-		continue;
-	    case CRT_MAP: {
-		Tcl_Obj *patchedDict = NULL, *subcmdObj;
-
-		/*
-		 * Verify that the map is sensible.
-		 */
-
-		if (Tcl_DictObjFirst(interp, objv[1], &search,
-			&subcmdObj, &listObj, &done) != TCL_OK) {
-		    if (allocatedMapFlag) {
-			Tcl_DecrRefCount(mapObj);
-		    }
-		    return TCL_ERROR;
-		}
-		if (done) {
-		    mapObj = NULL;
-		    continue;
-		}
-		do {
-		    Tcl_Obj **listv;
-		    const char *cmd;
-
-		    if (TclListObjGetElements(interp, listObj, &len,
-			    &listv) != TCL_OK) {
-			Tcl_DictObjDone(&search);
-			if (patchedDict) {
-			    Tcl_DecrRefCount(patchedDict);
-			}
-			if (allocatedMapFlag) {
-			    Tcl_DecrRefCount(mapObj);
-			}
-			return TCL_ERROR;
-		    }
-		    if (len < 1) {
-			Tcl_SetResult(interp,
-				"ensemble subcommand implementations "
-				"must be non-empty lists", TCL_STATIC);
-			Tcl_DictObjDone(&search);
-			if (patchedDict) {
-			    Tcl_DecrRefCount(patchedDict);
-			}
-			if (allocatedMapFlag) {
-			    Tcl_DecrRefCount(mapObj);
-			}
-			return TCL_ERROR;
-		    }
-		    cmd = TclGetString(listv[0]);
-		    if (!(cmd[0] == ':' && cmd[1] == ':')) {
-			Tcl_Obj *newList = Tcl_NewListObj(len, listv);
-			Tcl_Obj *newCmd = Tcl_NewStringObj(nsPtr->fullName,-1);
-
-			if (nsPtr->parentPtr) {
-			    Tcl_AppendStringsToObj(newCmd, "::", NULL);
-			}
-			Tcl_AppendObjToObj(newCmd, listv[0]);
-			Tcl_ListObjReplace(NULL, newList, 0, 1, 1, &newCmd);
-			if (patchedDict == NULL) {
-			    patchedDict = Tcl_DuplicateObj(objv[1]);
-			}
-			Tcl_DictObjPut(NULL, patchedDict, subcmdObj, newList);
-		    }
-		    Tcl_DictObjNext(&search, &subcmdObj, &listObj, &done);
-		} while (!done);
-
-		if (allocatedMapFlag) {
-		    Tcl_DecrRefCount(mapObj);
-		}
-		mapObj = (patchedDict ? patchedDict : objv[1]);
-		if (patchedDict) {
-		    allocatedMapFlag = 1;
-		}
-		continue;
-	    }
-	    case CRT_PREFIX:
-		if (Tcl_GetBooleanFromObj(interp, objv[1],
-			&permitPrefix) != TCL_OK) {
-		    if (allocatedMapFlag) {
-			Tcl_DecrRefCount(mapObj);
-		    }
-		    return TCL_ERROR;
-		}
-		continue;
-	    case CRT_UNKNOWN:
-		if (TclListObjLength(interp, objv[1], &len) != TCL_OK) {
-		    if (allocatedMapFlag) {
-			Tcl_DecrRefCount(mapObj);
-		    }
-		    return TCL_ERROR;
-		}
-		unknownObj = (len > 0 ? objv[1] : NULL);
-		continue;
-	    }
-	}
-
-	/*
-	 * Create the ensemble. Note that this might delete another ensemble
-	 * linked to the same namespace, so we must be careful. However, we
-	 * should be OK because we only link the namespace into the list once
-	 * we've created it (and after any deletions have occurred.)
-	 */
-
-	token = Tcl_CreateEnsemble(interp, name, NULL,
-		(permitPrefix ? TCL_ENSEMBLE_PREFIX : 0));
-	Tcl_SetEnsembleSubcommandList(interp, token, subcmdObj);
-	Tcl_SetEnsembleMappingDict(interp, token, mapObj);
-	Tcl_SetEnsembleUnknownHandler(interp, token, unknownObj);
-	Tcl_SetEnsembleParameterList(interp, token, paramObj);
-
-	/*
-	 * Tricky! Must ensure that the result is not shared (command delete
-	 * traces could have corrupted the pristine object that we started
-	 * with). [Snit test rename-1.5]
-	 */
-
-	Tcl_ResetResult(interp);
-	Tcl_GetCommandFullName(interp, token, Tcl_GetObjResult(interp));
-	return TCL_OK;
-    }
-
-    case ENS_EXISTS:
-	if (objc != 4) {
-	    Tcl_WrongNumArgs(interp, 3, objv, "cmdname");
-	    return TCL_ERROR;
-	}
-	Tcl_SetObjResult(interp, Tcl_NewBooleanObj(
-		Tcl_FindEnsemble(interp, objv[3], 0) != NULL));
-	return TCL_OK;
-
-    case ENS_CONFIG:
-	if (objc < 4 || (objc != 5 && objc & 1)) {
-	    Tcl_WrongNumArgs(interp, 3, objv,
-		    "cmdname ?-option value ...? ?arg ...?");
-	    return TCL_ERROR;
-	}
-	token = Tcl_FindEnsemble(interp, objv[3], TCL_LEAVE_ERR_MSG);
-	if (token == NULL) {
-	    return TCL_ERROR;
-	}
-
-	if (objc == 5) {
-	    Tcl_Obj *resultObj = NULL;		/* silence gcc 4 warning */
-
-	    if (Tcl_GetIndexFromObj(interp, objv[4], configOptions, "option",
-		    0, &index) != TCL_OK) {
-		return TCL_ERROR;
-	    }
-	    switch ((enum EnsConfigOpts) index) {
-	    case CONF_SUBCMDS:
-		Tcl_GetEnsembleSubcommandList(NULL, token, &resultObj);
-		if (resultObj != NULL) {
-		    Tcl_SetObjResult(interp, resultObj);
-		}
-		break;
-	    case CONF_PARAM:
-		Tcl_GetEnsembleParameterList(NULL, token, &resultObj);
-		if (resultObj != NULL) {
-		    Tcl_SetObjResult(interp, resultObj);
-		}
-		break;
-	    case CONF_MAP:
-		Tcl_GetEnsembleMappingDict(NULL, token, &resultObj);
-		if (resultObj != NULL) {
-		    Tcl_SetObjResult(interp, resultObj);
-		}
-		break;
-	    case CONF_NAMESPACE: {
-		Tcl_Namespace *namespacePtr = NULL; /* silence gcc 4 warning */
-
-		Tcl_GetEnsembleNamespace(NULL, token, &namespacePtr);
-		Tcl_SetResult(interp, ((Namespace *)namespacePtr)->fullName,
-			TCL_VOLATILE);
-		break;
-	    }
-	    case CONF_PREFIX: {
-		int flags = 0;			/* silence gcc 4 warning */
-
-		Tcl_GetEnsembleFlags(NULL, token, &flags);
-		Tcl_SetObjResult(interp,
-			Tcl_NewBooleanObj(flags & TCL_ENSEMBLE_PREFIX));
-		break;
-	    }
-	    case CONF_UNKNOWN:
-		Tcl_GetEnsembleUnknownHandler(NULL, token, &resultObj);
-		if (resultObj != NULL) {
-		    Tcl_SetObjResult(interp, resultObj);
-		}
-		break;
-	    }
-	    return TCL_OK;
-
-	} else if (objc == 4) {
-	    /*
-	     * Produce list of all information.
-	     */
-
-	    Tcl_Obj *resultObj, *tmpObj = NULL;	/* silence gcc 4 warning */
-	    Tcl_Namespace *namespacePtr = NULL;	/* silence gcc 4 warning */
-	    int flags = 0;			/* silence gcc 4 warning */
-
-	    TclNewObj(resultObj);
-
-	    /* -map option */
-	    Tcl_ListObjAppendElement(NULL, resultObj,
-		    Tcl_NewStringObj(configOptions[CONF_MAP], -1));
-	    Tcl_GetEnsembleMappingDict(NULL, token, &tmpObj);
-	    Tcl_ListObjAppendElement(NULL, resultObj,
-		    (tmpObj != NULL) ? tmpObj : Tcl_NewObj());
-
-	    /* -namespace option */
-	    Tcl_ListObjAppendElement(NULL, resultObj,
-		    Tcl_NewStringObj(configOptions[CONF_NAMESPACE], -1));
-	    Tcl_GetEnsembleNamespace(NULL, token, &namespacePtr);
-	    Tcl_ListObjAppendElement(NULL, resultObj,
-		    Tcl_NewStringObj(((Namespace *)namespacePtr)->fullName,
-		    -1));
-
-	    /* -parameters option */
-	    Tcl_ListObjAppendElement(NULL, resultObj,
-		    Tcl_NewStringObj(configOptions[CONF_PARAM], -1));
-	    Tcl_GetEnsembleParameterList(NULL, token, &tmpObj);
-	    Tcl_ListObjAppendElement(NULL, resultObj,
-		    (tmpObj != NULL) ? tmpObj : Tcl_NewObj());
-
-	    /* -prefix option */
-	    Tcl_ListObjAppendElement(NULL, resultObj,
-		    Tcl_NewStringObj(configOptions[CONF_PREFIX], -1));
-	    Tcl_GetEnsembleFlags(NULL, token, &flags);
-	    Tcl_ListObjAppendElement(NULL, resultObj,
-		    Tcl_NewBooleanObj(flags & TCL_ENSEMBLE_PREFIX));
-
-	    /* -subcommands option */
-	    Tcl_ListObjAppendElement(NULL, resultObj,
-		    Tcl_NewStringObj(configOptions[CONF_SUBCMDS], -1));
-	    Tcl_GetEnsembleSubcommandList(NULL, token, &tmpObj);
-	    Tcl_ListObjAppendElement(NULL, resultObj,
-		    (tmpObj != NULL) ? tmpObj : Tcl_NewObj());
-
-	    /* -unknown option */
-	    Tcl_ListObjAppendElement(NULL, resultObj,
-		    Tcl_NewStringObj(configOptions[CONF_UNKNOWN], -1));
-	    Tcl_GetEnsembleUnknownHandler(NULL, token, &tmpObj);
-	    Tcl_ListObjAppendElement(NULL, resultObj,
-		    (tmpObj != NULL) ? tmpObj : Tcl_NewObj());
-
-	    Tcl_SetObjResult(interp, resultObj);
-	    return TCL_OK;
-	} else {
-	    Tcl_DictSearch search;
-	    Tcl_Obj *listObj;
-	    int done, len, allocatedMapFlag = 0;
-	    Tcl_Obj *subcmdObj = NULL, *mapObj = NULL, *paramObj = NULL,
-		    *unknownObj = NULL; /* Defaults, silence gcc 4 warnings */
-	    int permitPrefix, flags = 0;	/* silence gcc 4 warning */
-
-	    Tcl_GetEnsembleSubcommandList(NULL, token, &subcmdObj);
-	    Tcl_GetEnsembleMappingDict(NULL, token, &mapObj);
-	    Tcl_GetEnsembleParameterList(NULL, token, &paramObj);
-	    Tcl_GetEnsembleUnknownHandler(NULL, token, &unknownObj);
-	    Tcl_GetEnsembleFlags(NULL, token, &flags);
-	    permitPrefix = (flags & TCL_ENSEMBLE_PREFIX) != 0;
-
-	    objv += 4;
-	    objc -= 4;
-
-	    /*
-	     * Parse the option list, applying type checks as we go. Note that
-	     * we are not incrementing any reference counts in the objects at
-	     * this stage, so the presence of an option multiple times won't
-	     * cause any memory leaks.
-	     */
-
-	    for (; objc>0 ; objc-=2,objv+=2) {
-		if (Tcl_GetIndexFromObj(interp, objv[0], configOptions,
-			"option", 0, &index) != TCL_OK) {
-		    if (allocatedMapFlag) {
-			Tcl_DecrRefCount(mapObj);
-		    }
-		    return TCL_ERROR;
-		}
-		switch ((enum EnsConfigOpts) index) {
-		case CONF_SUBCMDS:
-		    if (TclListObjLength(interp, objv[1], &len) != TCL_OK) {
-			if (allocatedMapFlag) {
-			    Tcl_DecrRefCount(mapObj);
-			}
-			return TCL_ERROR;
-		    }
-		    subcmdObj = (len > 0 ? objv[1] : NULL);
-		    continue;
-		case CONF_PARAM:
-		    if (TclListObjLength(interp, objv[1], &len) != TCL_OK) {
-			if (allocatedMapFlag) {
-			    Tcl_DecrRefCount(mapObj);
-			}
-			return TCL_ERROR;
-		    }
-		    paramObj = (len > 0 ? objv[1] : NULL);
-		    continue;
-		case CONF_MAP: {
-		    Tcl_Obj *patchedDict = NULL, *subcmdObj;
-
-		    /*
-		     * Verify that the map is sensible.
-		     */
-
-		    if (Tcl_DictObjFirst(interp, objv[1], &search,
-			    &subcmdObj, &listObj, &done) != TCL_OK) {
-			if (allocatedMapFlag) {
-			    Tcl_DecrRefCount(mapObj);
-			}
-			return TCL_ERROR;
-		    }
-		    if (done) {
-			mapObj = NULL;
-			continue;
-		    }
-		    do {
-			Tcl_Obj **listv;
-			const char *cmd;
-
-			if (TclListObjGetElements(interp, listObj, &len,
-				&listv) != TCL_OK) {
-			    Tcl_DictObjDone(&search);
-			    if (patchedDict) {
-				Tcl_DecrRefCount(patchedDict);
-			    }
-			    if (allocatedMapFlag) {
-				Tcl_DecrRefCount(mapObj);
-			    }
-			    return TCL_ERROR;
-			}
-			if (len < 1) {
-			    Tcl_SetResult(interp,
-				    "ensemble subcommand implementations "
-				    "must be non-empty lists", TCL_STATIC);
-			    Tcl_DictObjDone(&search);
-			    if (patchedDict) {
-				Tcl_DecrRefCount(patchedDict);
-			    }
-			    if (allocatedMapFlag) {
-				Tcl_DecrRefCount(mapObj);
-			    }
-			    return TCL_ERROR;
-			}
-			cmd = TclGetString(listv[0]);
-			if (!(cmd[0] == ':' && cmd[1] == ':')) {
-			    Tcl_Obj *newList = Tcl_NewListObj(len, listv);
-			    Tcl_Obj *newCmd =
-				    Tcl_NewStringObj(nsPtr->fullName, -1);
-			    if (nsPtr->parentPtr) {
-				Tcl_AppendStringsToObj(newCmd, "::", NULL);
-			    }
-			    Tcl_AppendObjToObj(newCmd, listv[0]);
-			    Tcl_ListObjReplace(NULL, newList, 0,1, 1,&newCmd);
-			    if (patchedDict == NULL) {
-				patchedDict = Tcl_DuplicateObj(objv[1]);
-			    }
-			    Tcl_DictObjPut(NULL, patchedDict, subcmdObj,
-				    newList);
-			}
-			Tcl_DictObjNext(&search, &subcmdObj, &listObj, &done);
-		    } while (!done);
-		    if (allocatedMapFlag) {
-			Tcl_DecrRefCount(mapObj);
-		    }
-		    mapObj = (patchedDict ? patchedDict : objv[1]);
-		    if (patchedDict) {
-			allocatedMapFlag = 1;
-		    }
-		    continue;
-		}
-		case CONF_NAMESPACE:
-		    if (allocatedMapFlag) {
-			Tcl_DecrRefCount(mapObj);
-		    }
-		    Tcl_AppendResult(interp, "option -namespace is read-only",
-			    NULL);
-		    return TCL_ERROR;
-		case CONF_PREFIX:
-		    if (Tcl_GetBooleanFromObj(interp, objv[1],
-			    &permitPrefix) != TCL_OK) {
-			if (allocatedMapFlag) {
-			    Tcl_DecrRefCount(mapObj);
-			}
-			return TCL_ERROR;
-		    }
-		    continue;
-		case CONF_UNKNOWN:
-		    if (TclListObjLength(interp, objv[1], &len) != TCL_OK) {
-			if (allocatedMapFlag) {
-			    Tcl_DecrRefCount(mapObj);
-			}
-			return TCL_ERROR;
-		    }
-		    unknownObj = (len > 0 ? objv[1] : NULL);
-		    continue;
-		}
-	    }
-
-	    /*
-	     * Update the namespace now that we've finished the parsing stage.
-	     */
-
-	    flags = (permitPrefix ? flags|TCL_ENSEMBLE_PREFIX
-		    : flags&~TCL_ENSEMBLE_PREFIX);
-	    Tcl_SetEnsembleSubcommandList(interp, token, subcmdObj);
-	    Tcl_SetEnsembleMappingDict(interp, token, mapObj);
-	    Tcl_SetEnsembleParameterList(interp, token, paramObj);
-	    Tcl_SetEnsembleUnknownHandler(interp, token, unknownObj);
-	    Tcl_SetEnsembleFlags(interp, token, flags);
-	    return TCL_OK;
-	}
-
-    default:
-	Tcl_Panic("unexpected ensemble command");
-    }
-    return TCL_OK;
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * Tcl_CreateEnsemble --
- *
- *	Create a simple ensemble attached to the given namespace.
- *
- * Results:
- *	The token for the command created.
- *
- * Side effects:
- *	The ensemble is created and marked for compilation.
- *
- *----------------------------------------------------------------------
- */
-
-Tcl_Command
-Tcl_CreateEnsemble(
-    Tcl_Interp *interp,
-    const char *name,
-    Tcl_Namespace *namespacePtr,
-    int flags)
-{
-    Namespace *nsPtr = (Namespace *) namespacePtr;
-    EnsembleConfig *ensemblePtr = (EnsembleConfig *)
-	    ckalloc(sizeof(EnsembleConfig));
-    Tcl_Obj *nameObj = NULL;
-
-    if (nsPtr == NULL) {
-	nsPtr = (Namespace *) TclGetCurrentNamespace(interp);
-    }
-
-    /*
-     * Make the name of the ensemble into a fully qualified name. This might
-     * allocate a temporary object.
-     */
-
-    if (!(name[0] == ':' && name[1] == ':')) {
-	nameObj = Tcl_NewStringObj(nsPtr->fullName, -1);
-	if (nsPtr->parentPtr == NULL) {
-	    Tcl_AppendStringsToObj(nameObj, name, NULL);
-	} else {
-	    Tcl_AppendStringsToObj(nameObj, "::", name, NULL);
-	}
-	Tcl_IncrRefCount(nameObj);
-	name = TclGetString(nameObj);
-    }
-
-    ensemblePtr->nsPtr = nsPtr;
-    ensemblePtr->epoch = 0;
-    Tcl_InitHashTable(&ensemblePtr->subcommandTable, TCL_STRING_KEYS);
-    ensemblePtr->subcommandArrayPtr = NULL;
-    ensemblePtr->subcmdList = NULL;
-    ensemblePtr->subcommandDict = NULL;
-    ensemblePtr->flags = flags;
-    ensemblePtr->numParameters = 0;
-    ensemblePtr->parameterList = NULL;
-    ensemblePtr->unknownHandler = NULL;
-    ensemblePtr->token = Tcl_NRCreateCommand(interp, name,
-	    NsEnsembleImplementationCmd, NsEnsembleImplementationCmdNR,
-	    ensemblePtr, DeleteEnsembleConfig);
-    ensemblePtr->next = (EnsembleConfig *) nsPtr->ensembles;
-    nsPtr->ensembles = (Tcl_Ensemble *) ensemblePtr;
-
-    /*
-     * Trigger an eventual recomputation of the ensemble command set. Note
-     * that this is slightly tricky, as it means that we are not actually
-     * counting the number of namespace export actions, but it is the simplest
-     * way to go!
-     */
-
-    nsPtr->exportLookupEpoch++;
-
-    if (flags & ENSEMBLE_COMPILE) {
-	((Command *) ensemblePtr->token)->compileProc = TclCompileEnsemble;
-    }
-
-    if (nameObj != NULL) {
-	TclDecrRefCount(nameObj);
-    }
-    return ensemblePtr->token;
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * Tcl_SetEnsembleSubcommandList --
- *
- *	Set the subcommand list for a particular ensemble.
- *
- * Results:
- *	Tcl result code (error if command token does not indicate an ensemble
- *	or the subcommand list - if non-NULL - is not a list).
- *
- * Side effects:
- *	The ensemble is updated and marked for recompilation.
- *
- *----------------------------------------------------------------------
- */
-
-int
-Tcl_SetEnsembleSubcommandList(
-    Tcl_Interp *interp,
-    Tcl_Command token,
-    Tcl_Obj *subcmdList)
-{
-    Command *cmdPtr = (Command *) token;
-    EnsembleConfig *ensemblePtr;
-    Tcl_Obj *oldList;
-
-    if (cmdPtr->objProc != NsEnsembleImplementationCmd) {
-	Tcl_AppendResult(interp, "command is not an ensemble", NULL);
-	return TCL_ERROR;
-    }
-    if (subcmdList != NULL) {
-	int length;
-
-	if (TclListObjLength(interp, subcmdList, &length) != TCL_OK) {
-	    return TCL_ERROR;
-	}
-	if (length < 1) {
-	    subcmdList = NULL;
-	}
-    }
-
-    ensemblePtr = cmdPtr->objClientData;
-    oldList = ensemblePtr->subcmdList;
-    ensemblePtr->subcmdList = subcmdList;
-    if (subcmdList != NULL) {
-	Tcl_IncrRefCount(subcmdList);
-    }
-    if (oldList != NULL) {
-	TclDecrRefCount(oldList);
-    }
-
-    /*
-     * Trigger an eventual recomputation of the ensemble command set. Note
-     * that this is slightly tricky, as it means that we are not actually
-     * counting the number of namespace export actions, but it is the simplest
-     * way to go!
-     */
-
-    ensemblePtr->nsPtr->exportLookupEpoch++;
-
-    /*
-     * Special hack to make compiling of [info exists] work when the
-     * dictionary is modified.
-     */
-
-    if (cmdPtr->compileProc != NULL) {
-	((Interp *)interp)->compileEpoch++;
-    }
-
-    return TCL_OK;
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * Tcl_SetEnsembleParameterList --
- *
- *	Set the parameter list for a particular ensemble.
- *
- * Results:
- *	Tcl result code (error if command token does not indicate an ensemble
- *	or the parameter list - if non-NULL - is not a list).
- *
- * Side effects:
- *	The ensemble is updated and marked for recompilation.
- *
- *----------------------------------------------------------------------
- */
-
-int
-Tcl_SetEnsembleParameterList(
-    Tcl_Interp *interp,
-    Tcl_Command token,
-    Tcl_Obj *paramList)
-{
-    Command *cmdPtr = (Command *) token;
-    EnsembleConfig *ensemblePtr;
-    Tcl_Obj *oldList;
-    int length;
-
-    if (cmdPtr->objProc != NsEnsembleImplementationCmd) {
-	Tcl_AppendResult(interp, "command is not an ensemble", NULL);
-	return TCL_ERROR;
-    }
-    if (paramList == NULL) {
-	length = 0;
-    } else {
-	if (TclListObjLength(interp, paramList, &length) != TCL_OK) {
-	    return TCL_ERROR;
-	}
-	if (length < 1) {
-	    paramList = NULL;
-	}
-    }
-
-    ensemblePtr = cmdPtr->objClientData;
-    oldList = ensemblePtr->parameterList;
-    ensemblePtr->parameterList = paramList;
-    if (paramList != NULL) {
-	Tcl_IncrRefCount(paramList);
-    }
-    if (oldList != NULL) {
-	TclDecrRefCount(oldList);
-    }
-    ensemblePtr->numParameters = length;
-
-    /*
-     * Trigger an eventual recomputation of the ensemble command set. Note
-     * that this is slightly tricky, as it means that we are not actually
-     * counting the number of namespace export actions, but it is the simplest
-     * way to go!
-     */
-
-    ensemblePtr->nsPtr->exportLookupEpoch++;
-
-    /*
-     * Special hack to make compiling of [info exists] work when the
-     * dictionary is modified.
-     */
-
-    if (cmdPtr->compileProc != NULL) {
-	((Interp *)interp)->compileEpoch++;
-    }
-
-    return TCL_OK;
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * Tcl_SetEnsembleMappingDict --
- *
- *	Set the mapping dictionary for a particular ensemble.
- *
- * Results:
- *	Tcl result code (error if command token does not indicate an ensemble
- *	or the mapping - if non-NULL - is not a dict).
- *
- * Side effects:
- *	The ensemble is updated and marked for recompilation.
- *
- *----------------------------------------------------------------------
- */
-
-int
-Tcl_SetEnsembleMappingDict(
-    Tcl_Interp *interp,
-    Tcl_Command token,
-    Tcl_Obj *mapDict)
-{
-    Command *cmdPtr = (Command *) token;
-    EnsembleConfig *ensemblePtr;
-    Tcl_Obj *oldDict;
-
-    if (cmdPtr->objProc != NsEnsembleImplementationCmd) {
-	Tcl_AppendResult(interp, "command is not an ensemble", NULL);
-	return TCL_ERROR;
-    }
-    if (mapDict != NULL) {
-	int size, done;
-	Tcl_DictSearch search;
-	Tcl_Obj *valuePtr;
-
-	if (Tcl_DictObjSize(interp, mapDict, &size) != TCL_OK) {
-	    return TCL_ERROR;
-	}
-
-	for (Tcl_DictObjFirst(NULL, mapDict, &search, NULL, &valuePtr, &done);
-		!done; Tcl_DictObjNext(&search, NULL, &valuePtr, &done)) {
-	    Tcl_Obj *cmdPtr;
-	    const char *bytes;
-
-	    if (Tcl_ListObjIndex(interp, valuePtr, 0, &cmdPtr) != TCL_OK) {
-		Tcl_DictObjDone(&search);
-		return TCL_ERROR;
-	    }
-	    bytes = TclGetString(cmdPtr);
-	    if (bytes[0] != ':' || bytes[1] != ':') {
-		Tcl_AppendResult(interp,
-			"ensemble target is not a fully-qualified command",
-			NULL);
-		Tcl_DictObjDone(&search);
-		return TCL_ERROR;
-	    }
-	}
-
-	if (size < 1) {
-	    mapDict = NULL;
-	}
-    }
-
-    ensemblePtr = cmdPtr->objClientData;
-    oldDict = ensemblePtr->subcommandDict;
-    ensemblePtr->subcommandDict = mapDict;
-    if (mapDict != NULL) {
-	Tcl_IncrRefCount(mapDict);
-    }
-    if (oldDict != NULL) {
-	TclDecrRefCount(oldDict);
-    }
-
-    /*
-     * Trigger an eventual recomputation of the ensemble command set. Note
-     * that this is slightly tricky, as it means that we are not actually
-     * counting the number of namespace export actions, but it is the simplest
-     * way to go!
-     */
-
-    ensemblePtr->nsPtr->exportLookupEpoch++;
-
-    /*
-     * Special hack to make compiling of [info exists] work when the
-     * dictionary is modified.
-     */
-
-    if (cmdPtr->compileProc != NULL) {
-	((Interp *)interp)->compileEpoch++;
-    }
-
-    return TCL_OK;
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * Tcl_SetEnsembleUnknownHandler --
- *
- *	Set the unknown handler for a particular ensemble.
- *
- * Results:
- *	Tcl result code (error if command token does not indicate an ensemble
- *	or the unknown handler - if non-NULL - is not a list).
- *
- * Side effects:
- *	The ensemble is updated and marked for recompilation.
- *
- *----------------------------------------------------------------------
- */
-
-int
-Tcl_SetEnsembleUnknownHandler(
-    Tcl_Interp *interp,
-    Tcl_Command token,
-    Tcl_Obj *unknownList)
-{
-    Command *cmdPtr = (Command *) token;
-    EnsembleConfig *ensemblePtr;
-    Tcl_Obj *oldList;
-
-    if (cmdPtr->objProc != NsEnsembleImplementationCmd) {
-	Tcl_AppendResult(interp, "command is not an ensemble", NULL);
-	return TCL_ERROR;
-    }
-    if (unknownList != NULL) {
-	int length;
-
-	if (TclListObjLength(interp, unknownList, &length) != TCL_OK) {
-	    return TCL_ERROR;
-	}
-	if (length < 1) {
-	    unknownList = NULL;
-	}
-    }
-
-    ensemblePtr = cmdPtr->objClientData;
-    oldList = ensemblePtr->unknownHandler;
-    ensemblePtr->unknownHandler = unknownList;
-    if (unknownList != NULL) {
-	Tcl_IncrRefCount(unknownList);
-    }
-    if (oldList != NULL) {
-	TclDecrRefCount(oldList);
-    }
-
-    /*
-     * Trigger an eventual recomputation of the ensemble command set. Note
-     * that this is slightly tricky, as it means that we are not actually
-     * counting the number of namespace export actions, but it is the simplest
-     * way to go!
-     */
-
-    ensemblePtr->nsPtr->exportLookupEpoch++;
-
-    return TCL_OK;
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * Tcl_SetEnsembleFlags --
- *
- *	Set the flags for a particular ensemble.
- *
- * Results:
- *	Tcl result code (error if command token does not indicate an
- *	ensemble).
- *
- * Side effects:
- *	The ensemble is updated and marked for recompilation.
- *
- *----------------------------------------------------------------------
- */
-
-int
-Tcl_SetEnsembleFlags(
-    Tcl_Interp *interp,
-    Tcl_Command token,
-    int flags)
-{
-    Command *cmdPtr = (Command *) token;
-    EnsembleConfig *ensemblePtr;
-    int wasCompiled;
-
-    if (cmdPtr->objProc != NsEnsembleImplementationCmd) {
-	Tcl_AppendResult(interp, "command is not an ensemble", NULL);
-	return TCL_ERROR;
-    }
-
-    ensemblePtr = cmdPtr->objClientData;
-    wasCompiled = ensemblePtr->flags & ENSEMBLE_COMPILE;
-
-    /*
-     * This API refuses to set the ENS_DEAD flag...
-     */
-
-    ensemblePtr->flags &= ENS_DEAD;
-    ensemblePtr->flags |= flags & ~ENS_DEAD;
-
-    /*
-     * Trigger an eventual recomputation of the ensemble command set. Note
-     * that this is slightly tricky, as it means that we are not actually
-     * counting the number of namespace export actions, but it is the simplest
-     * way to go!
-     */
-
-    ensemblePtr->nsPtr->exportLookupEpoch++;
-
-    /*
-     * If the ENSEMBLE_COMPILE flag status was changed, install or remove the
-     * compiler function and bump the interpreter's compilation epoch so that
-     * bytecode gets regenerated.
-     */
-
-    if (flags & ENSEMBLE_COMPILE) {
-	if (!wasCompiled) {
-	    ((Command*) ensemblePtr->token)->compileProc = TclCompileEnsemble;
-	    ((Interp *) interp)->compileEpoch++;
-	}
-    } else {
-	if (wasCompiled) {
-	    ((Command*) ensemblePtr->token)->compileProc = NULL;
-	    ((Interp *) interp)->compileEpoch++;
-	}
-    }
-
-    return TCL_OK;
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * Tcl_GetEnsembleSubcommandList --
- *
- *	Get the list of subcommands associated with a particular ensemble.
- *
- * Results:
- *	Tcl result code (error if command token does not indicate an
- *	ensemble). The list of subcommands is returned by updating the
- *	variable pointed to by the last parameter (NULL if this is to be
- *	derived from the mapping dictionary or the associated namespace's
- *	exported commands).
- *
- * Side effects:
- *	None
- *
- *----------------------------------------------------------------------
- */
-
-int
-Tcl_GetEnsembleSubcommandList(
-    Tcl_Interp *interp,
-    Tcl_Command token,
-    Tcl_Obj **subcmdListPtr)
-{
-    Command *cmdPtr = (Command *) token;
-    EnsembleConfig *ensemblePtr;
-
-    if (cmdPtr->objProc != NsEnsembleImplementationCmd) {
-	if (interp != NULL) {
-	    Tcl_AppendResult(interp, "command is not an ensemble", NULL);
-	}
-	return TCL_ERROR;
-    }
-
-    ensemblePtr = cmdPtr->objClientData;
-    *subcmdListPtr = ensemblePtr->subcmdList;
-    return TCL_OK;
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * Tcl_GetEnsembleParameterList --
- *
- *	Get the list of parameters associated with a particular ensemble.
- *
- * Results:
- *	Tcl result code (error if command token does not indicate an
- *	ensemble). The list of parameters is returned by updating the
- *	variable pointed to by the last parameter (NULL if there are
- *	no parameters).
- *
- * Side effects:
- *	None
- *
- *----------------------------------------------------------------------
- */
-
-int
-Tcl_GetEnsembleParameterList(
-    Tcl_Interp *interp,
-    Tcl_Command token,
-    Tcl_Obj **paramListPtr)
-{
-    Command *cmdPtr = (Command *) token;
-    EnsembleConfig *ensemblePtr;
-
-    if (cmdPtr->objProc != NsEnsembleImplementationCmd) {
-	if (interp != NULL) {
-	    Tcl_AppendResult(interp, "command is not an ensemble", NULL);
-	}
-	return TCL_ERROR;
-    }
-
-    ensemblePtr = cmdPtr->objClientData;
-    *paramListPtr = ensemblePtr->parameterList;
-    return TCL_OK;
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * Tcl_GetEnsembleMappingDict --
- *
- *	Get the command mapping dictionary associated with a particular
- *	ensemble.
- *
- * Results:
- *	Tcl result code (error if command token does not indicate an
- *	ensemble). The mapping dict is returned by updating the variable
- *	pointed to by the last parameter (NULL if none is installed).
- *
- * Side effects:
- *	None
- *
- *----------------------------------------------------------------------
- */
-
-int
-Tcl_GetEnsembleMappingDict(
-    Tcl_Interp *interp,
-    Tcl_Command token,
-    Tcl_Obj **mapDictPtr)
-{
-    Command *cmdPtr = (Command *) token;
-    EnsembleConfig *ensemblePtr;
-
-    if (cmdPtr->objProc != NsEnsembleImplementationCmd) {
-	if (interp != NULL) {
-	    Tcl_AppendResult(interp, "command is not an ensemble", NULL);
-	}
-	return TCL_ERROR;
-    }
-
-    ensemblePtr = cmdPtr->objClientData;
-    *mapDictPtr = ensemblePtr->subcommandDict;
-    return TCL_OK;
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * Tcl_GetEnsembleUnknownHandler --
- *
- *	Get the unknown handler associated with a particular ensemble.
- *
- * Results:
- *	Tcl result code (error if command token does not indicate an
- *	ensemble). The unknown handler is returned by updating the variable
- *	pointed to by the last parameter (NULL if no handler is installed).
- *
- * Side effects:
- *	None
- *
- *----------------------------------------------------------------------
- */
-
-int
-Tcl_GetEnsembleUnknownHandler(
-    Tcl_Interp *interp,
-    Tcl_Command token,
-    Tcl_Obj **unknownListPtr)
-{
-    Command *cmdPtr = (Command *) token;
-    EnsembleConfig *ensemblePtr;
-
-    if (cmdPtr->objProc != NsEnsembleImplementationCmd) {
-	if (interp != NULL) {
-	    Tcl_AppendResult(interp, "command is not an ensemble", NULL);
-	}
-	return TCL_ERROR;
-    }
-
-    ensemblePtr = cmdPtr->objClientData;
-    *unknownListPtr = ensemblePtr->unknownHandler;
-    return TCL_OK;
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * Tcl_GetEnsembleFlags --
- *
- *	Get the flags for a particular ensemble.
- *
- * Results:
- *	Tcl result code (error if command token does not indicate an
- *	ensemble). The flags are returned by updating the variable pointed to
- *	by the last parameter.
- *
- * Side effects:
- *	None
- *
- *----------------------------------------------------------------------
- */
-
-int
-Tcl_GetEnsembleFlags(
-    Tcl_Interp *interp,
-    Tcl_Command token,
-    int *flagsPtr)
-{
-    Command *cmdPtr = (Command *) token;
-    EnsembleConfig *ensemblePtr;
-
-    if (cmdPtr->objProc != NsEnsembleImplementationCmd) {
-	if (interp != NULL) {
-	    Tcl_AppendResult(interp, "command is not an ensemble", NULL);
-	}
-	return TCL_ERROR;
-    }
-
-    ensemblePtr = cmdPtr->objClientData;
-    *flagsPtr = ensemblePtr->flags;
-    return TCL_OK;
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * Tcl_GetEnsembleNamespace --
- *
- *	Get the namespace associated with a particular ensemble.
- *
- * Results:
- *	Tcl result code (error if command token does not indicate an
- *	ensemble). Namespace is returned by updating the variable pointed to
- *	by the last parameter.
- *
- * Side effects:
- *	None
- *
- *----------------------------------------------------------------------
- */
-
-int
-Tcl_GetEnsembleNamespace(
-    Tcl_Interp *interp,
-    Tcl_Command token,
-    Tcl_Namespace **namespacePtrPtr)
-{
-    Command *cmdPtr = (Command *) token;
-    EnsembleConfig *ensemblePtr;
-
-    if (cmdPtr->objProc != NsEnsembleImplementationCmd) {
-	if (interp != NULL) {
-	    Tcl_AppendResult(interp, "command is not an ensemble", NULL);
-	}
-	return TCL_ERROR;
-    }
-
-    ensemblePtr = cmdPtr->objClientData;
-    *namespacePtrPtr = (Tcl_Namespace *) ensemblePtr->nsPtr;
-    return TCL_OK;
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * Tcl_FindEnsemble --
- *
- *	Given a command name, get the ensemble token for it, allowing for
- *	[namespace import]s. [Bug 1017022]
- *
- * Results:
- *	The token for the ensemble command with the given name, or NULL if the
- *	command either does not exist or is not an ensemble (when an error
- *	message will be written into the interp if thats non-NULL).
- *
- * Side effects:
- *	None
- *
- *----------------------------------------------------------------------
- */
-
-Tcl_Command
-Tcl_FindEnsemble(
-    Tcl_Interp *interp,		/* Where to do the lookup, and where to write
-				 * the errors if TCL_LEAVE_ERR_MSG is set in
-				 * the flags. */
-    Tcl_Obj *cmdNameObj,	/* Name of command to look up. */
-    int flags)			/* Either 0 or TCL_LEAVE_ERR_MSG; other flags
-				 * are probably not useful. */
-{
-    Command *cmdPtr;
-
-    cmdPtr = (Command *)
-	    Tcl_FindCommand(interp, TclGetString(cmdNameObj), NULL, flags);
-    if (cmdPtr == NULL) {
-	return NULL;
-    }
-
-    if (cmdPtr->objProc != NsEnsembleImplementationCmd) {
-	/*
-	 * Reuse existing infrastructure for following import link chains
-	 * rather than duplicating it.
-	 */
-
-	cmdPtr = (Command *) TclGetOriginalCommand((Tcl_Command) cmdPtr);
-
-	if (cmdPtr == NULL || cmdPtr->objProc != NsEnsembleImplementationCmd){
-	    if (flags & TCL_LEAVE_ERR_MSG) {
-		Tcl_AppendResult(interp, "\"", TclGetString(cmdNameObj),
-			"\" is not an ensemble command", NULL);
-		Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "ENSEMBLE",
-			TclGetString(cmdNameObj), NULL);
-	    }
-	    return NULL;
-	}
-    }
-
-    return (Tcl_Command) cmdPtr;
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * Tcl_IsEnsemble --
- *
- *	Simple test for ensemble-hood that takes into account imported
- *	ensemble commands as well.
- *
- * Results:
- *	Boolean value
- *
- * Side effects:
- *	None
- *
- *----------------------------------------------------------------------
- */
-
-int
-Tcl_IsEnsemble(
-    Tcl_Command token)
-{
-    Command *cmdPtr = (Command *) token;
-    if (cmdPtr->objProc == NsEnsembleImplementationCmd) {
-	return 1;
-    }
-    cmdPtr = (Command *) TclGetOriginalCommand((Tcl_Command) cmdPtr);
-    if (cmdPtr == NULL || cmdPtr->objProc != NsEnsembleImplementationCmd) {
-	return 0;
-    }
-    return 1;
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * TclMakeEnsemble --
- *
- *	Create an ensemble from a table of implementation commands. The
- *	ensemble will be subject to (limited) compilation if any of the
- *	implementation commands are compilable.
- *
- *	The 'name' parameter may be a single command name or a list if
- *	creating an ensemble subcommand (see the binary implementation).
- *
- *	Currently, the TCL_ENSEMBLE_PREFIX ensemble flag is only used on
- *	top-level ensemble commands.
- *
- * Results:
- *	Handle for the new ensemble, or NULL on failure.
- *
- * Side effects:
- *	May advance the bytecode compilation epoch.
- *
- *----------------------------------------------------------------------
- */
-
-Tcl_Command
-TclMakeEnsemble(
-    Tcl_Interp *interp,
-    const char *name,		 /* The ensemble name (as explained above) */
-    const EnsembleImplMap map[]) /* The subcommands to create */
-{
-    Tcl_Command ensemble;
-    Tcl_Namespace *ns;
-    Tcl_DString buf;
-    const char **nameParts = NULL;
-    const char *cmdName = NULL;
-    int i, nameCount = 0, ensembleFlags = 0;
-
-    /*
-     * Construct the path for the ensemble namespace and create it.
-     */
-
-    Tcl_DStringInit(&buf);
-    if (name[0] == ':' && name[1] == ':') {
-	/*
-	 * An absolute name, so use it directly.
-	 */
-
-	cmdName = name;
-	Tcl_DStringAppend(&buf, name, -1);
-	ensembleFlags = TCL_ENSEMBLE_PREFIX;
-    } else {
-	/*
-	 * Not an absolute name, so do munging of it. Note that this treats a
-	 * multi-word list differently to a single word.
-	 */
-
-	Tcl_DStringAppend(&buf, "::tcl", -1);
-
-	if (Tcl_SplitList(NULL, name, &nameCount, &nameParts) != TCL_OK) {
-	    Tcl_Panic("invalid ensemble name '%s'", name);
-	}
-
-	for (i = 0; i < nameCount; ++i) {
-	    Tcl_DStringAppend(&buf, "::", 2);
-	    Tcl_DStringAppend(&buf, nameParts[i], -1);
-	}
-    }
-
-    ns = Tcl_FindNamespace(interp, Tcl_DStringValue(&buf), NULL,
-	    TCL_CREATE_NS_IF_UNKNOWN);
-    if (!ns) {
-	Tcl_Panic("unable to find or create %s namespace!",
-		Tcl_DStringValue(&buf));
-    }
-
-    /*
-     * Create the named ensemble in the correct namespace
-     */
-
-    if (cmdName == NULL) {
-	if (nameCount == 1) {
-	    ensembleFlags = TCL_ENSEMBLE_PREFIX;
-	    cmdName = Tcl_DStringValue(&buf) + 5;
-	} else {
-	    ns = ns->parentPtr;
-	    cmdName = nameParts[nameCount - 1];
-	}
-    }
-    ensemble = Tcl_CreateEnsemble(interp, cmdName, ns, ensembleFlags);
-
-    /*
-     * Create the ensemble mapping dictionary and the ensemble command procs.
-     */
-
-    if (ensemble != NULL) {
-	Tcl_Obj *mapDict;
-
-	Tcl_DStringAppend(&buf, "::", 2);
-	TclNewObj(mapDict);
-	for (i=0 ; map[i].name != NULL ; i++) {
-	    Tcl_Obj *fromObj, *toObj;
-	    Command *cmdPtr;
-
-	    fromObj = Tcl_NewStringObj(map[i].name, -1);
-	    TclNewStringObj(toObj, Tcl_DStringValue(&buf),
-		    Tcl_DStringLength(&buf));
-	    Tcl_AppendToObj(toObj, map[i].name, -1);
-	    Tcl_DictObjPut(NULL, mapDict, fromObj, toObj);
-	    if (map[i].proc || map[i].nreProc) {
-		cmdPtr = (Command *)
-			Tcl_NRCreateCommand(interp, TclGetString(toObj),
-			map[i].proc, map[i].nreProc, map[i].clientData, NULL);
-		cmdPtr->compileProc = map[i].compileProc;
-		if (map[i].compileProc != NULL) {
-		    ensembleFlags |= ENSEMBLE_COMPILE;
-		}
-	    }
-	}
-	Tcl_SetEnsembleMappingDict(interp, ensemble, mapDict);
-	if (ensembleFlags & ENSEMBLE_COMPILE) {
-	    Tcl_SetEnsembleFlags(interp, ensemble, ensembleFlags);
-	}
-    }
-
-    Tcl_DStringFree(&buf);
-    if (nameParts != NULL) {
-	Tcl_Free((char *) nameParts);
-    }
-    return ensemble;
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * NsEnsembleImplementationCmd --
- *
- *	Implements an ensemble of commands (being those exported by a
- *	namespace other than the global namespace) as a command with the same
- *	(short) name as the namespace in the parent namespace.
- *
- * Results:
- *	A standard Tcl result code. Will be TCL_ERROR if the command is not an
- *	unambiguous prefix of any command exported by the ensemble's
- *	namespace.
- *
- * Side effects:
- *	Depends on the command within the namespace that gets executed. If the
- *	ensemble itself returns TCL_ERROR, a descriptive error message will be
- *	placed in the interpreter's result.
- *
- *----------------------------------------------------------------------
- */
-
-static int
-NsEnsembleImplementationCmd(
-    ClientData clientData,
-    Tcl_Interp *interp,
-    int objc,
-    Tcl_Obj *const objv[])
-{
-    return Tcl_NRCallObjProc(interp, NsEnsembleImplementationCmdNR,
-	    clientData, objc, objv);
-}
-
-static int
-NsEnsembleImplementationCmdNR(
-    ClientData clientData,
-    Tcl_Interp *interp,
-    int objc,
-    Tcl_Obj *const objv[])
-{
-    EnsembleConfig *ensemblePtr = clientData;
-				/* The ensemble itself. */
-    Tcl_Obj *prefixObj;		/* An object containing the prefix words of
-				 * the command that implements the
-				 * subcommand. */
-    Tcl_HashEntry *hPtr;	/* Used for efficient lookup of fully
-				 * specified but not yet cached command
-				 * names. */
-    int reparseCount = 0;	/* Number of reparses. */
-
-    /*
-     * Must recheck objc, since numParameters might have changed. Cf. test
-     * namespace-53.9.
-     */
-
-  restartEnsembleParse:
-    if (objc < 2 + ensemblePtr->numParameters) {
-	/*
-	 * We don't have a subcommand argument. Make error message.
-	 */
-
-	Tcl_DString buf;	/* Message being built */
-	Tcl_Obj **elemPtrs;	/* Parameter names */
-	int len;		/* Number of parameters to append */
-
-	Tcl_DStringInit(&buf);
-	if (ensemblePtr->parameterList == NULL) {
-	    len = 0;
-	} else if (TclListObjGetElements(NULL, ensemblePtr->parameterList,
-		&len, &elemPtrs) != TCL_OK) {
-	    Tcl_Panic("List of ensemble parameters is not a list");
-	}
-	for (; len>0; len--,elemPtrs++) {
-	    Tcl_DStringAppend(&buf, Tcl_GetString(*elemPtrs), -1);
-	    Tcl_DStringAppend(&buf, " ", -1);
-	}
-	Tcl_DStringAppend(&buf, "subcommand ?arg ...?", -1);
-	Tcl_WrongNumArgs(interp, 1, objv, Tcl_DStringValue(&buf));
-	Tcl_DStringFree(&buf);
-
-	return TCL_ERROR;
-    }
-
-    if (ensemblePtr->nsPtr->flags & NS_DYING) {
-	/*
-	 * Don't know how we got here, but make things give up quickly.
-	 */
-
-	if (!Tcl_InterpDeleted(interp)) {
-	    Tcl_AppendResult(interp,
-		    "ensemble activated for deleted namespace", NULL);
-	}
-	return TCL_ERROR;
-    }
-
-    /*
-     * Determine if the table of subcommands is right. If so, we can just look
-     * up in there and go straight to dispatch.
-     */
-
-    if (ensemblePtr->epoch == ensemblePtr->nsPtr->exportLookupEpoch) {
-	/*
-	 * Table of subcommands is still valid; therefore there might be a
-	 * valid cache of discovered information which we can reuse. Do the
-	 * check here, and if we're still valid, we can jump straight to the
-	 * part where we do the invocation of the subcommand.
-	 */
-
-	if (objv[1+ensemblePtr->numParameters]->typePtr==&tclEnsembleCmdType){
-	    EnsembleCmdRep *ensembleCmd = objv[1+ensemblePtr->numParameters]
-		    ->internalRep.otherValuePtr;
-
-	    if (ensembleCmd->nsPtr == ensemblePtr->nsPtr &&
-		    ensembleCmd->epoch == ensemblePtr->epoch &&
-		    ensembleCmd->token == ensemblePtr->token) {
-		prefixObj = ensembleCmd->realPrefixObj;
-		Tcl_IncrRefCount(prefixObj);
-		goto runResultingSubcommand;
-	    }
-	}
-    } else {
-	BuildEnsembleConfig(ensemblePtr);
-	ensemblePtr->epoch = ensemblePtr->nsPtr->exportLookupEpoch;
-    }
-
-    /*
-     * Look in the hashtable for the subcommand name; this is the fastest way
-     * of all if there is no cache in operation.
-     */
-
-    hPtr = Tcl_FindHashEntry(&ensemblePtr->subcommandTable,
-	    TclGetString(objv[1 + ensemblePtr->numParameters]));
-    if (hPtr != NULL) {
-	char *fullName = Tcl_GetHashKey(&ensemblePtr->subcommandTable, hPtr);
-
-	prefixObj = Tcl_GetHashValue(hPtr);
-
-	/*
-	 * Cache for later in the subcommand object.
-	 */
-
-	MakeCachedEnsembleCommand(objv[1 + ensemblePtr->numParameters],
-		ensemblePtr, fullName, prefixObj);
-    } else if (!(ensemblePtr->flags & TCL_ENSEMBLE_PREFIX)) {
-	/*
-	 * Could not map, no prefixing, go to unknown/error handling.
-	 */
-
-	goto unknownOrAmbiguousSubcommand;
-    } else {
-	/*
-	 * If we've not already confirmed the command with the hash as part of
-	 * building our export table, we need to scan the sorted array for
-	 * matches.
-	 */
-
-	const char *subcmdName; /* Name of the subcommand, or unique prefix of
-				 * it (will be an error for a non-unique
-				 * prefix). */
-	char *fullName = NULL;	/* Full name of the subcommand. */
-	int stringLength, i;
-	int tableLength = ensemblePtr->subcommandTable.numEntries;
-
-	subcmdName = TclGetString(objv[1 + ensemblePtr->numParameters]);
-	stringLength = objv[1 + ensemblePtr->numParameters]->length;
-	for (i=0 ; i<tableLength ; i++) {
-	    register int cmp = strncmp(subcmdName,
-		    ensemblePtr->subcommandArrayPtr[i],
-		    (unsigned) stringLength);
-
-	    if (cmp == 0) {
-		if (fullName != NULL) {
-		    /*
-		     * Since there's never the exact-match case to worry about
-		     * (hash search filters this), getting here indicates that
-		     * our subcommand is an ambiguous prefix of (at least) two
-		     * exported subcommands, which is an error case.
-		     */
-
-		    goto unknownOrAmbiguousSubcommand;
-		}
-		fullName = ensemblePtr->subcommandArrayPtr[i];
-	    } else if (cmp < 0) {
-		/*
-		 * Because we are searching a sorted table, we can now stop
-		 * searching because we have gone past anything that could
-		 * possibly match.
-		 */
-
-		break;
-	    }
-	}
-	if (fullName == NULL) {
-	    /*
-	     * The subcommand is not a prefix of anything, so bail out!
-	     */
-
-	    goto unknownOrAmbiguousSubcommand;
-	}
-	hPtr = Tcl_FindHashEntry(&ensemblePtr->subcommandTable, fullName);
-	if (hPtr == NULL) {
-	    Tcl_Panic("full name %s not found in supposedly synchronized hash",
-		    fullName);
-	}
-	prefixObj = Tcl_GetHashValue(hPtr);
-
-	/*
-	 * Cache for later in the subcommand object.
-	 */
-
-	MakeCachedEnsembleCommand(objv[1 + ensemblePtr->numParameters],
-		ensemblePtr, fullName, prefixObj);
-    }
-
-    Tcl_IncrRefCount(prefixObj);
-  runResultingSubcommand:
-
-    /*
-     * Do the real work of execution of the subcommand by building an array of
-     * objects (note that this is potentially not the same length as the
-     * number of arguments to this ensemble command), populating it and then
-     * feeding it back through the main command-lookup engine. In theory, we
-     * could look up the command in the namespace ourselves, as we already
-     * have the namespace in which it is guaranteed to exist,
-     *
-     *   ((Q: That's not true if the -map option is used, is it?))
-     *
-     * but we don't do that (the cacheing of the command object used should
-     * help with that.)
-     */
-
-    {
-	Tcl_Obj **prefixObjv;	/* The list of objects to substitute in as the
-				 * target command prefix. */
-	Tcl_Obj *copyPtr;	/* The actual list of words to dispatch to.
-				 * Will be freed by the dispatch engine. */
-	int prefixObjc, copyObjc;
-	Interp *iPtr = (Interp *) interp;
-
-	/*
-	 * Get the prefix that we're rewriting to. To do this we need to
-	 * ensure that the internal representation of the list does not change
-	 * so that we can safely keep the internal representations of the
-	 * elements in the list.
-	 *
-	 * TODO: Use conventional list operations to make this code sane!
-	 */
-
-	TclListObjGetElements(NULL, prefixObj, &prefixObjc, &prefixObjv);
-
-	copyObjc = objc - 2 + prefixObjc;
-	copyPtr = Tcl_NewListObj(copyObjc, NULL);
-	if (copyObjc > 0) {
-	    register Tcl_Obj **copyObjv;
-				/* Space used to construct the list of
-				 * arguments to pass to the command that
-				 * implements the ensemble subcommand. */
-	    register List *listRepPtr = copyPtr->internalRep.twoPtrValue.ptr1;
-	    register int i;
-
-	    listRepPtr->elemCount = copyObjc;
-	    copyObjv = &listRepPtr->elements;
-	    memcpy(copyObjv, prefixObjv, sizeof(Tcl_Obj *) * prefixObjc);
-	    memcpy(copyObjv+prefixObjc, objv+1,
-		    sizeof(Tcl_Obj *) * ensemblePtr->numParameters);
-	    memcpy(copyObjv+prefixObjc+ensemblePtr->numParameters,
-		    objv+ensemblePtr->numParameters+2,
-		    sizeof(Tcl_Obj *) * (objc-ensemblePtr->numParameters-2));
-
-	    for (i=0; i < copyObjc; i++) {
-		Tcl_IncrRefCount(copyObjv[i]);
-	    }
-	}
-	TclDecrRefCount(prefixObj);
-
-	/*
-	 * Record what arguments the script sent in so that things like
-	 * Tcl_WrongNumArgs can give the correct error message. Parameters
-	 * count both as inserted and removed arguments.
-	 */
-
-#if 0
-	if (TclInitRewriteEnsemble(interp, 2 + ensemblePtr->numParameters, prefixObjc + ensemblePtr->numParameters, objv)) {
-	    TclNRAddCallback(interp, TclClearRootEnsemble, NULL, NULL, NULL, NULL);
-	}
-#else
-	if (iPtr->ensembleRewrite.sourceObjs == NULL) {
-	    iPtr->ensembleRewrite.sourceObjs = objv;
-	    iPtr->ensembleRewrite.numRemovedObjs =
-		    2 + ensemblePtr->numParameters;
-	    iPtr->ensembleRewrite.numInsertedObjs =
-		    prefixObjc + ensemblePtr->numParameters;
-	    TclNRAddCallback(interp, TclClearRootEnsemble, NULL, NULL, NULL,
-		    NULL);
-	} else {
-	    register int ni = 2 + ensemblePtr->numParameters
-		    - iPtr->ensembleRewrite.numInsertedObjs;
-				/* Position in objv of new front of insertion
-				 * relative to old one. */
-	    if (ni > 0) {
-		iPtr->ensembleRewrite.numRemovedObjs += ni;
-		iPtr->ensembleRewrite.numInsertedObjs += prefixObjc-1;
-	    } else {
-		iPtr->ensembleRewrite.numInsertedObjs += prefixObjc-2;
-	    }
-	}
-#endif
-
-	/*
-	 * Hand off to the target command.
-	 */
-
-	iPtr->evalFlags |= TCL_EVAL_REDIRECT;	
-	return Tcl_NREvalObj(interp, copyPtr, TCL_EVAL_INVOKE);
-    }
-
-  unknownOrAmbiguousSubcommand:
-    /*
-     * Have not been able to match the subcommand asked for with a real
-     * subcommand that we export. See whether a handler has been registered
-     * for dealing with this situation. Will only call (at most) once for any
-     * particular ensemble invocation.
-     */
-
-    if (ensemblePtr->unknownHandler != NULL && reparseCount++ < 1) {
-	switch (EnsembleUnknownCallback(interp, ensemblePtr, objc, objv,
-		&prefixObj)) {
-	case TCL_OK:
-	    goto runResultingSubcommand;
-	case TCL_ERROR:
-	    return TCL_ERROR;
-	case TCL_CONTINUE:
-	    goto restartEnsembleParse;
-	}
-    }
-
-    /*
-     * We cannot determine what subcommand to hand off to, so generate a
-     * (standard) failure message. Note the one odd case compared with
-     * standard ensemble-like command, which is where a namespace has no
-     * exported commands at all...
-     */
-
-    Tcl_ResetResult(interp);
-    Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "ENSEMBLE",
-	    TclGetString(objv[1+ensemblePtr->numParameters]), NULL);
-    if (ensemblePtr->subcommandTable.numEntries == 0) {
-	Tcl_AppendResult(interp, "unknown subcommand \"",
-		TclGetString(objv[1+ensemblePtr->numParameters]),
-		"\": namespace ", ensemblePtr->nsPtr->fullName,
-		" does not export any commands", NULL);
-	Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "SUBCOMMAND",
-		TclGetString(objv[1+ensemblePtr->numParameters]), NULL);
-	return TCL_ERROR;
-    }
-    Tcl_AppendResult(interp, "unknown ",
-	    (ensemblePtr->flags & TCL_ENSEMBLE_PREFIX ? "or ambiguous " : ""),
-	    "subcommand \"", TclGetString(objv[1+ensemblePtr->numParameters]),
-	    "\": must be ", NULL);
-    if (ensemblePtr->subcommandTable.numEntries == 1) {
-	Tcl_AppendResult(interp, ensemblePtr->subcommandArrayPtr[0], NULL);
-    } else {
-	int i;
-
-	for (i=0 ; i<ensemblePtr->subcommandTable.numEntries-1 ; i++) {
-	    Tcl_AppendResult(interp,
-		    ensemblePtr->subcommandArrayPtr[i], ", ", NULL);
-	}
-	Tcl_AppendResult(interp, "or ",
-		ensemblePtr->subcommandArrayPtr[i], NULL);
-    }
-    Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "SUBCOMMAND",
-	    TclGetString(objv[1+ensemblePtr->numParameters]), NULL);
-    return TCL_ERROR;
-}
-
-int
-TclClearRootEnsemble(
-    ClientData data[],
-    Tcl_Interp *interp,
-    int result)
-{
-    TclResetRewriteEnsemble(interp, 1);
-    return result;
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * TclInitRewriteEnsemble --
- *
- *	Applies a rewrite of arguments so that an ensemble subcommand will
- *	report error messages correctly for the overall command.
- *
- * Results:
- *	Whether this is the first rewrite applied, a value which must be
- *	passed to TclResetRewriteEnsemble when undoing this command's
- *	behaviour.
- *
- * Side effects:
- *	None.
- *
- *----------------------------------------------------------------------
- */
-
-int
-TclInitRewriteEnsemble(
-    Tcl_Interp *interp,
-    int numRemoved,
-    int numInserted,
-    Tcl_Obj *const *objv)
-{
-    Interp *iPtr = (Interp *) interp;
-
-    int isRootEnsemble = (iPtr->ensembleRewrite.sourceObjs == NULL);
-
-    if (isRootEnsemble) {
-        iPtr->ensembleRewrite.sourceObjs = objv;
-        iPtr->ensembleRewrite.numRemovedObjs = numRemoved;
-        iPtr->ensembleRewrite.numInsertedObjs = numInserted;
-    } else {
-        int numIns = iPtr->ensembleRewrite.numInsertedObjs;
-
-        if (numIns < numRemoved) {
-            iPtr->ensembleRewrite.numRemovedObjs += numRemoved - numIns;
-            iPtr->ensembleRewrite.numInsertedObjs += numInserted - 1;
-        } else {
-            iPtr->ensembleRewrite.numInsertedObjs += numInserted - numRemoved;
-        }
-    }
-    return isRootEnsemble;
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * TclResetRewriteEnsemble --
- *
- *	Removes any rewrites applied to support proper reporting of error
- *	messages used in ensembles. Should be paired with
- *	TclInitRewriteEnsemble.
- *
- * Results:
- *	None.
- *
- * Side effects:
- *	None.
- *
- *----------------------------------------------------------------------
- */
-
-void
-TclResetRewriteEnsemble(
-    Tcl_Interp *interp,
-    int isRootEnsemble)
-{
-    Interp *iPtr = (Interp *) interp;
-
-    if (isRootEnsemble) {
-        iPtr->ensembleRewrite.sourceObjs = NULL;
-        iPtr->ensembleRewrite.numRemovedObjs = 0;
-        iPtr->ensembleRewrite.numInsertedObjs = 0;
-    }
-}
-
-/*
- * ----------------------------------------------------------------------
- *
- * EnsmebleUnknownCallback --
- *
- *	Helper for the ensemble engine that handles the procesing of unknown
- *	callbacks. See the user documentation of the ensemble unknown handler
- *	for details; this function is only ever called when such a function is
- *	defined, and is only ever called once per ensemble dispatch (i.e. if a
- *	reparse still fails, this isn't called again).
- *
- * Results:
- *	TCL_OK -	*prefixObjPtr contains the command words to dispatch
- *			to.
- *	TCL_CONTINUE -	Need to reparse (*prefixObjPtr is invalid).
- *	TCL_ERROR -	Something went wrong! Error message in interpreter.
- *
- * Side effects:
- *	Calls the Tcl interpreter, so arbitrary.
- *
- * ----------------------------------------------------------------------
- */
-
-static inline int
-EnsembleUnknownCallback(
-    Tcl_Interp *interp,
-    EnsembleConfig *ensemblePtr,
-    int objc,
-    Tcl_Obj *const objv[],
-    Tcl_Obj **prefixObjPtr)
-{
-    int paramc, i, result, prefixObjc;
-    Tcl_Obj **paramv, *unknownCmd, *ensObj;
-    char buf[TCL_INTEGER_SPACE];
-
-    /*
-     * Create the unknown command callback to determine what to do.
-     */
-
-    unknownCmd = Tcl_DuplicateObj(ensemblePtr->unknownHandler);
-    TclNewObj(ensObj);
-    Tcl_GetCommandFullName(interp, ensemblePtr->token, ensObj);
-    Tcl_ListObjAppendElement(NULL, unknownCmd, ensObj);
-    for (i=1 ; i<objc ; i++) {
-	Tcl_ListObjAppendElement(NULL, unknownCmd, objv[i]);
-    }
-    TclListObjGetElements(NULL, unknownCmd, &paramc, &paramv);
-    Tcl_IncrRefCount(unknownCmd);
-
-    /*
-     * Now call the unknown handler. (We don't bother NRE-enabling this; deep
-     * recursing through unknown handlers is horribly perverse.) Note that it
-     * is always an error for an unknown handler to delete its ensemble; don't
-     * do that!
-     */
-
-    Tcl_Preserve(ensemblePtr);
-    ((Interp *)interp)->evalFlags |= TCL_EVAL_REDIRECT;    
-    result = Tcl_EvalObjv(interp, paramc, paramv, 0);
-    if ((result == TCL_OK) && (ensemblePtr->flags & ENS_DEAD)) {
-	Tcl_SetResult(interp,
-		"unknown subcommand handler deleted its ensemble",
-		TCL_STATIC);
-	result = TCL_ERROR;
-    }
-    Tcl_Release(ensemblePtr);
-
-    /*
-     * If we succeeded, we should either have a list of words that form the
-     * command to be executed, or an empty list. In the empty-list case, the
-     * ensemble is believed to be updated so we should ask the ensemble engine
-     * to reparse the original command.
-     */
-
-    if (result == TCL_OK) {
-	*prefixObjPtr = Tcl_GetObjResult(interp);
-	Tcl_IncrRefCount(*prefixObjPtr);
-	TclDecrRefCount(unknownCmd);
-	Tcl_ResetResult(interp);
-
-	/*
-	 * Namespace is still there. Check if the result is a valid list. If
-	 * it is, and it is non-empty, that list is what we are using as our
-	 * replacement.
-	 */
-
-	if (TclListObjLength(interp, *prefixObjPtr, &prefixObjc) != TCL_OK) {
-	    TclDecrRefCount(*prefixObjPtr);
-	    Tcl_AddErrorInfo(interp, "\n    while parsing result of "
-		    "ensemble unknown subcommand handler");
-	    return TCL_ERROR;
-	}
-	if (prefixObjc > 0) {
-	    return TCL_OK;
-	}
-
-	/*
-	 * Namespace alive & empty result => reparse.
-	 */
-
-	TclDecrRefCount(*prefixObjPtr);
-	return TCL_CONTINUE;
-    }
-
-    /*
-     * Oh no! An exceptional result. Convert to an error.
-     */
-
-    if (!Tcl_InterpDeleted(interp)) {
-	if (result != TCL_ERROR) {
-	    Tcl_ResetResult(interp);
-	    Tcl_SetResult(interp,
-		    "unknown subcommand handler returned bad code: ",
-		    TCL_STATIC);
-	    switch (result) {
-	    case TCL_RETURN:
-		Tcl_AppendResult(interp, "return", NULL);
-		break;
-	    case TCL_BREAK:
-		Tcl_AppendResult(interp, "break", NULL);
-		break;
-	    case TCL_CONTINUE:
-		Tcl_AppendResult(interp, "continue", NULL);
-		break;
-	    default:
-		sprintf(buf, "%d", result);
-		Tcl_AppendResult(interp, buf, NULL);
-	    }
-	    Tcl_AddErrorInfo(interp, "\n    result of "
-		    "ensemble unknown subcommand handler: ");
-	    Tcl_AddErrorInfo(interp, TclGetString(unknownCmd));
-	} else {
-	    Tcl_AddErrorInfo(interp,
-		    "\n    (ensemble unknown subcommand handler)");
-	}
-    }
-    TclDecrRefCount(unknownCmd);
-    return TCL_ERROR;
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * MakeCachedEnsembleCommand --
- *
- *	Cache what we've computed so far; it's not nice to repeatedly copy
- *	strings about. Note that to do this, we start by deleting any old
- *	representation that there was (though if it was an out of date
- *	ensemble rep, we can skip some of the deallocation process.)
- *
- * Results:
- *	None
- *
- * Side effects:
- *	Alters the internal representation of the first object parameter.
- *
- *----------------------------------------------------------------------
- */
-
-static void
-MakeCachedEnsembleCommand(
-    Tcl_Obj *objPtr,
-    EnsembleConfig *ensemblePtr,
-    const char *subcommandName,
-    Tcl_Obj *prefixObjPtr)
-{
-    register EnsembleCmdRep *ensembleCmd;
-    int length;
-
-    if (objPtr->typePtr == &tclEnsembleCmdType) {
-	ensembleCmd = objPtr->internalRep.otherValuePtr;
-	Tcl_DecrRefCount(ensembleCmd->realPrefixObj);
-	ensembleCmd->nsPtr->refCount--;
-	if ((ensembleCmd->nsPtr->refCount == 0)
-		&& (ensembleCmd->nsPtr->flags & NS_DEAD)) {
-	    NamespaceFree(ensembleCmd->nsPtr);
-	}
-	ckfree(ensembleCmd->fullSubcmdName);
-    } else {
-	/*
-	 * Kill the old internal rep, and replace it with a brand new one of
-	 * our own.
-	 */
-
-	TclFreeIntRep(objPtr);
-	ensembleCmd = (EnsembleCmdRep *) ckalloc(sizeof(EnsembleCmdRep));
-	objPtr->internalRep.otherValuePtr = ensembleCmd;
-	objPtr->typePtr = &tclEnsembleCmdType;
-    }
-
-    /*
-     * Populate the internal rep.
-     */
-
-    ensembleCmd->nsPtr = ensemblePtr->nsPtr;
-    ensembleCmd->epoch = ensemblePtr->epoch;
-    ensembleCmd->token = ensemblePtr->token;
-    ensemblePtr->nsPtr->refCount++;
-    ensembleCmd->realPrefixObj = prefixObjPtr;
-    length = strlen(subcommandName)+1;
-    ensembleCmd->fullSubcmdName = ckalloc((unsigned) length);
-    memcpy(ensembleCmd->fullSubcmdName, subcommandName, (unsigned) length);
-    Tcl_IncrRefCount(ensembleCmd->realPrefixObj);
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * DeleteEnsembleConfig --
- *
- *	Destroys the data structure used to represent an ensemble. This is
- *	called when the ensemble's command is deleted (which happens
- *	automatically if the ensemble's namespace is deleted.) Maintainers
- *	should note that ensembles should be deleted by deleting their
- *	commands.
- *
- * Results:
- *	None.
- *
- * Side effects:
- *	Memory is (eventually) deallocated.
- *
- *----------------------------------------------------------------------
- */
-
-static void
-DeleteEnsembleConfig(
-    ClientData clientData)
-{
-    EnsembleConfig *ensemblePtr = clientData;
-    Namespace *nsPtr = ensemblePtr->nsPtr;
-    Tcl_HashSearch search;
-    Tcl_HashEntry *hEnt;
-
-    /*
-     * Unlink from the ensemble chain if it has not been marked as having been
-     * done already.
-     */
-
-    if (ensemblePtr->next != ensemblePtr) {
-	EnsembleConfig *ensPtr = (EnsembleConfig *) nsPtr->ensembles;
-	if (ensPtr == ensemblePtr) {
-	    nsPtr->ensembles = (Tcl_Ensemble *) ensemblePtr->next;
-	} else {
-	    while (ensPtr != NULL) {
-		if (ensPtr->next == ensemblePtr) {
-		    ensPtr->next = ensemblePtr->next;
-		    break;
-		}
-		ensPtr = ensPtr->next;
-	    }
-	}
-    }
-
-    /*
-     * Mark the namespace as dead so code that uses Tcl_Preserve() can tell
-     * whether disaster happened anyway.
-     */
-
-    ensemblePtr->flags |= ENS_DEAD;
-
-    /*
-     * Kill the pointer-containing fields.
-     */
-
-    if (ensemblePtr->subcommandTable.numEntries != 0) {
-	ckfree((char *) ensemblePtr->subcommandArrayPtr);
-    }
-    hEnt = Tcl_FirstHashEntry(&ensemblePtr->subcommandTable, &search);
-    while (hEnt != NULL) {
-	Tcl_Obj *prefixObj = Tcl_GetHashValue(hEnt);
-
-	Tcl_DecrRefCount(prefixObj);
-	hEnt = Tcl_NextHashEntry(&search);
-    }
-    Tcl_DeleteHashTable(&ensemblePtr->subcommandTable);
-    if (ensemblePtr->subcmdList != NULL) {
-	Tcl_DecrRefCount(ensemblePtr->subcmdList);
-    }
-    if (ensemblePtr->parameterList != NULL) {
-	Tcl_DecrRefCount(ensemblePtr->parameterList);
-    }
-    if (ensemblePtr->subcommandDict != NULL) {
-	Tcl_DecrRefCount(ensemblePtr->subcommandDict);
-    }
-    if (ensemblePtr->unknownHandler != NULL) {
-	Tcl_DecrRefCount(ensemblePtr->unknownHandler);
-    }
-
-    /*
-     * Arrange for the structure to be reclaimed. Note that this is complex
-     * because we have to make sure that we can react sensibly when an
-     * ensemble is deleted during the process of initialising the ensemble
-     * (especially the unknown callback.)
-     */
-
-    Tcl_EventuallyFree(ensemblePtr, TCL_DYNAMIC);
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * BuildEnsembleConfig --
- *
- *	Create the internal data structures that describe how an ensemble
- *	looks, being a hash mapping from the full command name to the Tcl list
- *	that describes the implementation prefix words, and a sorted array of
- *	all the full command names to allow for reasonably efficient
- *	unambiguous prefix handling.
- *
- * Results:
- *	None.
- *
- * Side effects:
- *	Reallocates and rebuilds the hash table and array stored at the
- *	ensemblePtr argument. For large ensembles or large namespaces, this is
- *	a potentially expensive operation.
- *
- *----------------------------------------------------------------------
- */
-
-static void
-BuildEnsembleConfig(
-    EnsembleConfig *ensemblePtr)
-{
-    Tcl_HashSearch search;	/* Used for scanning the set of commands in
-				 * the namespace that backs up this
-				 * ensemble. */
-    int i, j, isNew;
-    Tcl_HashTable *hash = &ensemblePtr->subcommandTable;
-    Tcl_HashEntry *hPtr;
-
-    if (hash->numEntries != 0) {
-	/*
-	 * Remove pre-existing table.
-	 */
-
-	Tcl_HashSearch search;
-
-	ckfree((char *) ensemblePtr->subcommandArrayPtr);
-	hPtr = Tcl_FirstHashEntry(hash, &search);
-	while (hPtr != NULL) {
-	    Tcl_Obj *prefixObj = Tcl_GetHashValue(hPtr);
-	    Tcl_DecrRefCount(prefixObj);
-	    hPtr = Tcl_NextHashEntry(&search);
-	}
-	Tcl_DeleteHashTable(hash);
-	Tcl_InitHashTable(hash, TCL_STRING_KEYS);
-    }
-
-    /*
-     * See if we've got an export list. If so, we will only export exactly
-     * those commands, which may be either implemented by the prefix in the
-     * subcommandDict or mapped directly onto the namespace's commands.
-     */
-
-    if (ensemblePtr->subcmdList != NULL) {
-	Tcl_Obj **subcmdv, *target, *cmdObj, *cmdPrefixObj;
-	int subcmdc;
-
-	TclListObjGetElements(NULL, ensemblePtr->subcmdList, &subcmdc,
-		&subcmdv);
-	for (i=0 ; i<subcmdc ; i++) {
-	    const char *name = TclGetString(subcmdv[i]);
-
-	    hPtr = Tcl_CreateHashEntry(hash, name, &isNew);
-
-	    /*
-	     * Skip non-unique cases.
-	     */
-
-	    if (!isNew) {
-		continue;
-	    }
-
-	    /*
-	     * Look in our dictionary (if present) for the command.
-	     */
-
-	    if (ensemblePtr->subcommandDict != NULL) {
-		Tcl_DictObjGet(NULL, ensemblePtr->subcommandDict, subcmdv[i],
-			&target);
-		if (target != NULL) {
-		    Tcl_SetHashValue(hPtr, target);
-		    Tcl_IncrRefCount(target);
-		    continue;
-		}
-	    }
-
-	    /*
-	     * Not there, so map onto the namespace. Note in this case that we
-	     * do not guarantee that the command is actually there; that is
-	     * the programmer's responsibility (or [::unknown] of course).
-	     */
-
-	    cmdObj = Tcl_NewStringObj(ensemblePtr->nsPtr->fullName, -1);
-	    if (ensemblePtr->nsPtr->parentPtr != NULL) {
-		Tcl_AppendStringsToObj(cmdObj, "::", name, NULL);
-	    } else {
-		Tcl_AppendStringsToObj(cmdObj, name, NULL);
-	    }
-	    cmdPrefixObj = Tcl_NewListObj(1, &cmdObj);
-	    Tcl_SetHashValue(hPtr, cmdPrefixObj);
-	    Tcl_IncrRefCount(cmdPrefixObj);
-	}
-    } else if (ensemblePtr->subcommandDict != NULL) {
-	/*
-	 * No subcmd list, but we do have a mapping dictionary so we should
-	 * use the keys of that. Convert the dictionary's contents into the
-	 * form required for the ensemble's internal hashtable.
-	 */
-
-	Tcl_DictSearch dictSearch;
-	Tcl_Obj *keyObj, *valueObj;
-	int done;
-
-	Tcl_DictObjFirst(NULL, ensemblePtr->subcommandDict, &dictSearch,
-		&keyObj, &valueObj, &done);
-	while (!done) {
-	    const char *name = TclGetString(keyObj);
-
-	    hPtr = Tcl_CreateHashEntry(hash, name, &isNew);
-	    Tcl_SetHashValue(hPtr, valueObj);
-	    Tcl_IncrRefCount(valueObj);
-	    Tcl_DictObjNext(&dictSearch, &keyObj, &valueObj, &done);
-	}
-    } else {
-	/*
-	 * Discover what commands are actually exported by the namespace.
-	 * What we have is an array of patterns and a hash table whose keys
-	 * are the command names exported by the namespace (the contents do
-	 * not matter here.) We must find out what commands are actually
-	 * exported by filtering each command in the namespace against each of
-	 * the patterns in the export list. Note that we use an intermediate
-	 * hash table to make memory management easier, and because that makes
-	 * exact matching far easier too.
-	 *
-	 * Suggestion for future enhancement: compute the unique prefixes and
-	 * place them in the hash too, which should make for even faster
-	 * matching.
-	 */
-
-	hPtr = Tcl_FirstHashEntry(&ensemblePtr->nsPtr->cmdTable, &search);
-	for (; hPtr!= NULL ; hPtr=Tcl_NextHashEntry(&search)) {
-	    char *nsCmdName =		/* Name of command in namespace. */
-		    Tcl_GetHashKey(&ensemblePtr->nsPtr->cmdTable, hPtr);
-
-	    for (i=0 ; i<ensemblePtr->nsPtr->numExportPatterns ; i++) {
-		if (Tcl_StringMatch(nsCmdName,
-			ensemblePtr->nsPtr->exportArrayPtr[i])) {
-		    hPtr = Tcl_CreateHashEntry(hash, nsCmdName, &isNew);
-
-		    /*
-		     * Remember, hash entries have a full reference to the
-		     * substituted part of the command (as a list) as their
-		     * content!
-		     */
-
-		    if (isNew) {
-			Tcl_Obj *cmdObj, *cmdPrefixObj;
-
-			TclNewObj(cmdObj);
-			Tcl_AppendStringsToObj(cmdObj,
-				ensemblePtr->nsPtr->fullName,
-				(ensemblePtr->nsPtr->parentPtr ? "::" : ""),
-				nsCmdName, NULL);
-			cmdPrefixObj = Tcl_NewListObj(1, &cmdObj);
-			Tcl_SetHashValue(hPtr, cmdPrefixObj);
-			Tcl_IncrRefCount(cmdPrefixObj);
-		    }
-		    break;
-		}
-	    }
-	}
-    }
-
-    if (hash->numEntries == 0) {
-	ensemblePtr->subcommandArrayPtr = NULL;
-	return;
-    }
-
-    /*
-     * Create a sorted array of all subcommands in the ensemble; hash tables
-     * are all very well for a quick look for an exact match, but they can't
-     * determine things like whether a string is a prefix of another (not
-     * without lots of preparation anyway) and they're no good for when we're
-     * generating the error message either.
-     *
-     * We do this by filling an array with the names (we use the hash keys
-     * directly to save a copy, since any time we change the array we change
-     * the hash too, and vice versa) and running quicksort over the array.
-     */
-
-    ensemblePtr->subcommandArrayPtr = (char **)
-	    ckalloc(sizeof(char *) * hash->numEntries);
-
-    /*
-     * Fill array from both ends as this makes us less likely to end up with
-     * performance problems in qsort(), which is good. Note that doing this
-     * makes this code much more opaque, but the naive alternatve:
-     *
-     * for (hPtr=Tcl_FirstHashEntry(hash,&search),i=0 ;
-     *	       hPtr!=NULL ; hPtr=Tcl_NextHashEntry(&search),i++) {
-     *     ensemblePtr->subcommandArrayPtr[i] = Tcl_GetHashKey(hash, &hPtr);
-     * }
-     *
-     * can produce long runs of precisely ordered table entries when the
-     * commands in the namespace are declared in a sorted fashion (an ordering
-     * some people like) and the hashing functions (or the command names
-     * themselves) are fairly unfortunate. By filling from both ends, it
-     * requires active malice (and probably a debugger) to get qsort() to have
-     * awful runtime behaviour.
-     */
-
-    i = 0;
-    j = hash->numEntries;
-    hPtr = Tcl_FirstHashEntry(hash, &search);
-    while (hPtr != NULL) {
-	ensemblePtr->subcommandArrayPtr[i++] = Tcl_GetHashKey(hash, hPtr);
-	hPtr = Tcl_NextHashEntry(&search);
-	if (hPtr == NULL) {
-	    break;
-	}
-	ensemblePtr->subcommandArrayPtr[--j] = Tcl_GetHashKey(hash, hPtr);
-	hPtr = Tcl_NextHashEntry(&search);
-    }
-    if (hash->numEntries > 1) {
-	qsort(ensemblePtr->subcommandArrayPtr, (unsigned)hash->numEntries,
-		sizeof(char *), NsEnsembleStringOrder);
-    }
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * NsEnsembleStringOrder --
- *
- *	Helper function to compare two pointers to two strings for use with
- *	qsort().
- *
- * Results:
- *	-1 if the first string is smaller, 1 if the second string is smaller,
- *	and 0 if they are equal.
- *
- * Side effects:
- *	None.
- *
- *----------------------------------------------------------------------
- */
-
-static int
-NsEnsembleStringOrder(
-    const void *strPtr1,
-    const void *strPtr2)
-{
-    return strcmp(*(const char **)strPtr1, *(const char **)strPtr2);
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * FreeEnsembleCmdRep --
- *
- *	Destroys the internal representation of a Tcl_Obj that has been
- *	holding information about a command in an ensemble.
- *
- * Results:
- *	None.
- *
- * Side effects:
- *	Memory is deallocated. If this held the last reference to a
- *	namespace's main structure, that main structure will also be
- *	destroyed.
- *
- *----------------------------------------------------------------------
- */
-
-static void
-FreeEnsembleCmdRep(
-    Tcl_Obj *objPtr)
-{
-    EnsembleCmdRep *ensembleCmd = objPtr->internalRep.otherValuePtr;
-
-    Tcl_DecrRefCount(ensembleCmd->realPrefixObj);
-    ckfree(ensembleCmd->fullSubcmdName);
-    ensembleCmd->nsPtr->refCount--;
-    if ((ensembleCmd->nsPtr->refCount == 0)
-	    && (ensembleCmd->nsPtr->flags & NS_DEAD)) {
-	NamespaceFree(ensembleCmd->nsPtr);
-    }
-    ckfree((char *) ensembleCmd);
-    objPtr->typePtr = NULL;
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * DupEnsembleCmdRep --
- *
- *	Makes one Tcl_Obj into a copy of another that is a subcommand of an
- *	ensemble.
- *
- * Results:
- *	None.
- *
- * Side effects:
- *	Memory is allocated, and the namespace that the ensemble is built on
- *	top of gains another reference.
- *
- *----------------------------------------------------------------------
- */
-
-static void
-DupEnsembleCmdRep(
-    Tcl_Obj *objPtr,
-    Tcl_Obj *copyPtr)
-{
-    EnsembleCmdRep *ensembleCmd = objPtr->internalRep.otherValuePtr;
-    EnsembleCmdRep *ensembleCopy = (EnsembleCmdRep *)
-	    ckalloc(sizeof(EnsembleCmdRep));
-    int length = strlen(ensembleCmd->fullSubcmdName);
-
-    copyPtr->typePtr = &tclEnsembleCmdType;
-    copyPtr->internalRep.otherValuePtr = ensembleCopy;
-    ensembleCopy->nsPtr = ensembleCmd->nsPtr;
-    ensembleCopy->epoch = ensembleCmd->epoch;
-    ensembleCopy->token = ensembleCmd->token;
-    ensembleCopy->nsPtr->refCount++;
-    ensembleCopy->realPrefixObj = ensembleCmd->realPrefixObj;
-    Tcl_IncrRefCount(ensembleCopy->realPrefixObj);
-    ensembleCopy->fullSubcmdName = ckalloc((unsigned) length+1);
-    memcpy(ensembleCopy->fullSubcmdName, ensembleCmd->fullSubcmdName,
-	    (unsigned) length+1);
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * StringOfEnsembleCmdRep --
- *
- *	Creates a string representation of a Tcl_Obj that holds a subcommand
- *	of an ensemble.
- *
- * Results:
- *	None.
- *
- * Side effects:
- *	The object gains a string (UTF-8) representation.
- *
- *----------------------------------------------------------------------
- */
-
-static void
-StringOfEnsembleCmdRep(
-    Tcl_Obj *objPtr)
-{
-    EnsembleCmdRep *ensembleCmd = objPtr->internalRep.otherValuePtr;
-    int length = strlen(ensembleCmd->fullSubcmdName);
-
-    objPtr->length = length;
-    objPtr->bytes = ckalloc((unsigned) length+1);
-    memcpy(objPtr->bytes, ensembleCmd->fullSubcmdName, (unsigned) length+1);
-}
-
-/*
- *----------------------------------------------------------------------
- *
  * Tcl_LogCommandInfo --
  *
  *	This function is invoked after an error occurs in an interpreter. It
diff --git a/unix/Makefile.in b/unix/Makefile.in
index 81fb07b..e1c7314 100644
--- a/unix/Makefile.in
+++ b/unix/Makefile.in
@@ -4,7 +4,7 @@
 # "./configure", which is a configuration script generated by the "autoconf"
 # program (constructs like "@foo@" will get replaced in the actual Makefile.
 #
-# RCS: @(#) $Id: Makefile.in,v 1.288 2009/12/28 14:15:20 dkf Exp $
+# RCS: @(#) $Id: Makefile.in,v 1.289 2010/02/13 18:11:06 dkf Exp $
 
 VERSION 		= @TCL_VERSION@
 MAJOR_VERSION		= @TCL_MAJOR_VERSION@
@@ -296,6 +296,7 @@ GENERIC_OBJS = regcomp.o regexec.o regfree.o regerror.o tclAlloc.o \
 	tclAsync.o tclBasic.o tclBinary.o tclCkalloc.o tclClock.o \
 	tclCmdAH.o tclCmdIL.o tclCmdMZ.o tclCompCmds.o tclCompExpr.o \
 	tclCompile.o tclConfig.o tclDate.o tclDictObj.o tclEncoding.o \
+	tclEnsemble.o \
 	tclEnv.o tclEvent.o tclExecute.o tclFCmd.o tclFileName.o tclGet.o \
 	tclHash.o tclHistory.o tclIndexObj.o tclInterp.o tclIO.o tclIOCmd.o \
 	tclIORChan.o tclIORTrans.o tclIOGT.o tclIOSock.o tclIOUtil.o \
@@ -398,6 +399,7 @@ GENERIC_SRCS = \
 	$(GENERIC_DIR)/tclDate.c \
 	$(GENERIC_DIR)/tclDictObj.c \
 	$(GENERIC_DIR)/tclEncoding.c \
+	$(GENERIC_DIR)/tclEnsemble.c \
 	$(GENERIC_DIR)/tclEnv.c \
 	$(GENERIC_DIR)/tclEvent.c \
 	$(GENERIC_DIR)/tclExecute.c \
@@ -1048,6 +1050,9 @@ tclDictObj.o: $(GENERIC_DIR)/tclDictObj.c $(MATHHDRS)
 tclEncoding.o: $(GENERIC_DIR)/tclEncoding.c
 	$(CC) -c $(CC_SWITCHES) $(GENERIC_DIR)/tclEncoding.c
 
+tclEnsemble.o: $(GENERIC_DIR)/tclEnsemble.c $(COMPILEHDR)
+	$(CC) -c $(CC_SWITCHES) $(GENERIC_DIR)/tclEnsemble.c
+
 tclEnv.o: $(GENERIC_DIR)/tclEnv.c
 	$(CC) -c $(CC_SWITCHES) $(GENERIC_DIR)/tclEnv.c
 
@@ -1141,7 +1146,7 @@ tclLoadShl.o: $(UNIX_DIR)/tclLoadShl.c
 tclMain.o: $(GENERIC_DIR)/tclMain.c
 	$(CC) -c $(CC_SWITCHES) $(GENERIC_DIR)/tclMain.c
 
-tclNamesp.o: $(GENERIC_DIR)/tclNamesp.c 
+tclNamesp.o: $(GENERIC_DIR)/tclNamesp.c $(COMPILEHDR)
 	$(CC) -c $(CC_SWITCHES) $(GENERIC_DIR)/tclNamesp.c
 
 tclNotify.o: $(GENERIC_DIR)/tclNotify.c
diff --git a/win/Makefile.in b/win/Makefile.in
index 48b2e86..d7e1041 100644
--- a/win/Makefile.in
+++ b/win/Makefile.in
@@ -4,7 +4,7 @@
 # "./configure", which is a configuration script generated by the "autoconf"
 # program (constructs like "@foo@" will get replaced in the actual Makefile.
 #
-# RCS: @(#) $Id: Makefile.in,v 1.170 2009/12/17 16:28:21 dgp Exp $
+# RCS: @(#) $Id: Makefile.in,v 1.171 2010/02/13 18:11:06 dkf Exp $
 
 VERSION = @TCL_VERSION@
 
@@ -231,6 +231,7 @@ GENERIC_OBJS = \
 	tclDate.$(OBJEXT) \
 	tclDictObj.$(OBJEXT) \
 	tclEncoding.$(OBJEXT) \
+	tclEnsemble.$(OBJEXT) \
 	tclEnv.$(OBJEXT) \
 	tclEvent.$(OBJEXT) \
 	tclExecute.$(OBJEXT) \
diff --git a/win/makefile.bc b/win/makefile.bc
index 7666309..c66acfd 100644
--- a/win/makefile.bc
+++ b/win/makefile.bc
@@ -208,6 +208,7 @@ TCLOBJS	= \
 	$(TMPDIR)\tclDate.obj \
 	$(TMPDIR)\tclDictObj.obj \
 	$(TMPDIR)\tclEncoding.obj \
+	$(TMPDIR)\tclEnsemble.obj \
 	$(TMPDIR)\tclEnv.obj \
 	$(TMPDIR)\tclEvent.obj \
 	$(TMPDIR)\tclExecute.obj \
diff --git a/win/makefile.vc b/win/makefile.vc
index 08ac169..99718f2 100644
--- a/win/makefile.vc
+++ b/win/makefile.vc
@@ -13,7 +13,7 @@
 # Copyright (c) 2003-2008 Pat Thoyts.
 #
 #------------------------------------------------------------------------------
-# RCS: @(#) $Id: makefile.vc,v 1.205 2009/12/11 22:52:09 nijtmans Exp $
+# RCS: @(#) $Id: makefile.vc,v 1.206 2010/02/13 18:11:06 dkf Exp $
 #------------------------------------------------------------------------------
 
 # Check to see we are configured to build with MSVC (MSDEVDIR or MSVCDIR)
@@ -268,6 +268,7 @@ COREOBJS = \
 	$(TMP_DIR)\tclDate.obj \
 	$(TMP_DIR)\tclDictObj.obj \
 	$(TMP_DIR)\tclEncoding.obj \
+	$(TMP_DIR)\tclEnsemble.obj \
 	$(TMP_DIR)\tclEnv.obj \
 	$(TMP_DIR)\tclEvent.obj \
 	$(TMP_DIR)\tclExecute.obj \