/*
 * tclCompCmds.c --
 *
 *	This file contains compilation procedures that compile various
 *	Tcl commands into a sequence of instructions ("bytecodes").
 *
 * Copyright (c) 1997-1998 Sun Microsystems, Inc.
 * Copyright (c) 2001 by Kevin B. Kenny.  All rights reserved.
 * Copyright (c) 2002 ActiveState Corporation.
 * Copyright (c) 2004-2005 by 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: tclCompCmds.c,v 1.81 2005/11/02 14:51:04 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);
 */

#define CompileWord(envPtr, tokenPtr, interp) \
    if ((tokenPtr)->type == TCL_TOKEN_SIMPLE_WORD) { \
	TclEmitPush(TclRegisterNewLiteral((envPtr), (tokenPtr)[1].start, \
		(tokenPtr)[1].size), (envPtr)); \
    } else { \
	TclCompileTokens((interp), (tokenPtr)+1, (tokenPtr)->numComponents, \
		(envPtr)); \
    }

/*
 * 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)

/*
 * 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) \
    (((envPtr)->exceptDepth++), \
    ((envPtr)->maxExceptDepth = \
	    TclMax((envPtr)->exceptDepth, (envPtr)->maxExceptDepth)), \
    (TclCreateExceptRange((type), (envPtr))))
#define ExceptionRangeStarts(envPtr, index) \
    ((envPtr)->exceptArrayPtr[(index)].codeOffset = CurrentOffset(envPtr))
#define ExceptionRangeEnds(envPtr, index) \
    ((envPtr)->exceptArrayPtr[(index)].numCodeBytes = \
	CurrentOffset(envPtr) - (envPtr)->exceptArrayPtr[(index)].codeOffset)
#define ExceptionRangeTarget(envPtr, index, targetType) \
    ((envPtr)->exceptArrayPtr[(index)].targetType = CurrentOffset(envPtr))

/*
 * Prototypes for procedures defined later in this file:
 */

static ClientData	DupForeachInfo(ClientData clientData);
static void		FreeForeachInfo(ClientData clientData);
static int		PushVarName(Tcl_Interp *interp,
			    Tcl_Token *varTokenPtr, CompileEnv *envPtr,
			    int flags, int *localIndexPtr,
			    int *simpleVarNamePtr, int *isScalarPtr);

/*
 * Flags bits used by PushVarName.
 */

#define TCL_CREATE_VAR     1 /* Create a compiled local if none is found */
#define TCL_NO_LARGE_INDEX 2 /* Do not return localIndex value > 255 */

/*
 * The structures below define the AuxData types defined in this file.
 */

AuxDataType tclForeachInfoType = {
    "ForeachInfo",		/* name */
    DupForeachInfo,		/* dupProc */
    FreeForeachInfo		/* freeProc */
};

/*
 *----------------------------------------------------------------------
 *
 * TclCompileAppendCmd --
 *
 *	Procedure called to compile the "append" command.
 *
 * Results:
 * 	Returns TCL_OK for a successful compile. Returns TCL_ERROR to defer
 * 	evaluation to runtime.
 *
 * Side effects:
 *	Instructions are added to envPtr to execute the "append" command at
 *	runtime.
 *
 *----------------------------------------------------------------------
 */

int
TclCompileAppendCmd(
    Tcl_Interp *interp,		/* Used for error reporting. */
    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
				 * created by Tcl_ParseCommand. */
    CompileEnv *envPtr)		/* Holds resulting instructions. */
{
    Tcl_Token *varTokenPtr, *valueTokenPtr;
    int simpleVarName, isScalar, localIndex, numWords;

    numWords = parsePtr->numWords;
    if (numWords == 1) {
	return TCL_ERROR;
    } else if (numWords == 2) {
	/*
	 * append varName == set varName
	 */
	return TclCompileSetCmd(interp, parsePtr, envPtr);
    } else if (numWords > 3) {
	/*
	 * APPEND instructions currently only handle one value
	 */
	return TCL_ERROR;
    }

    /*
     * Decide if we can use a frame slot for the var/array name or if we need
     * to emit code to compute and push the name at runtime. We use a frame
     * slot (entry in the array of local vars) if we are compiling a procedure
     * body and if the name is simple text that does not include namespace
     * qualifiers.
     */

    varTokenPtr = TokenAfter(parsePtr->tokenPtr);

    PushVarName(interp, varTokenPtr, envPtr, TCL_CREATE_VAR,
	    &localIndex, &simpleVarName, &isScalar);

    /*
     * We are doing an assignment, otherwise TclCompileSetCmd was called, so
     * push the new value. This will need to be extended to push a value for
     * each argument.
     */

    if (numWords > 2) {
	valueTokenPtr = TokenAfter(varTokenPtr);
	CompileWord(envPtr, valueTokenPtr, interp);
    }

    /*
     * Emit instructions to set/get the variable.
     */

    if (simpleVarName) {
	if (isScalar) {
	    if (localIndex < 0) {
		TclEmitOpcode(INST_APPEND_STK, envPtr);
	    } else if (localIndex <= 255) {
		TclEmitInstInt1(INST_APPEND_SCALAR1, localIndex, envPtr);
	    } else {
		TclEmitInstInt4(INST_APPEND_SCALAR4, localIndex, envPtr);
	    }
	} else {
	    if (localIndex < 0) {
		TclEmitOpcode(INST_APPEND_ARRAY_STK, envPtr);
	    } else if (localIndex <= 255) {
		TclEmitInstInt1(INST_APPEND_ARRAY1, localIndex, envPtr);
	    } else {
		TclEmitInstInt4(INST_APPEND_ARRAY4, localIndex, envPtr);
	    }
	}
    } else {
	TclEmitOpcode(INST_APPEND_STK, envPtr);
    }

    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCompileBreakCmd --
 *
 *	Procedure called to compile the "break" command.
 *
 * Results:
 * 	Returns TCL_OK for a successful compile. Returns TCL_ERROR to defer
 * 	evaluation to runtime.
 *
 * Side effects:
 *	Instructions are added to envPtr to execute the "break" command at
 *	runtime.
 *
 *----------------------------------------------------------------------
 */

int
TclCompileBreakCmd(
    Tcl_Interp *interp,		/* Used for error reporting. */
    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
				 * created by Tcl_ParseCommand. */
    CompileEnv *envPtr)		/* Holds resulting instructions. */
{
    if (parsePtr->numWords != 1) {
	return TCL_ERROR;
    }

    /*
     * Emit a break instruction.
     */

    TclEmitOpcode(INST_BREAK, envPtr);
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCompileCatchCmd --
 *
 *	Procedure called to compile the "catch" command.
 *
 * Results:
 * 	Returns TCL_OK for a successful compile. Returns TCL_ERROR to defer
 * 	evaluation to runtime.
 *
 * Side effects:
 *	Instructions are added to envPtr to execute the "catch" command at
 *	runtime.
 *
 *----------------------------------------------------------------------
 */

int
TclCompileCatchCmd(
    Tcl_Interp *interp,		/* Used for error reporting. */
    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
				 * created by Tcl_ParseCommand. */
    CompileEnv *envPtr)		/* Holds resulting instructions. */
{
    JumpFixup jumpFixup;
    Tcl_Token *cmdTokenPtr, *resultNameTokenPtr, *optsNameTokenPtr;
    CONST char *name;
    int resultIndex, optsIndex, nameChars, range;
    int savedStackDepth = envPtr->currStackDepth;

    /*
     * If syntax does not match what we expect for [catch], do not compile.
     * Let runtime checks determine if syntax has changed.
     */
    if ((parsePtr->numWords < 2) || (parsePtr->numWords > 4)) {
	return TCL_ERROR;
    }

    /*
     * If variables were specified and the catch command is at global level
     * (not in a procedure), don't compile it inline: the payoff is too small.
     */

    if ((parsePtr->numWords >= 3) && (envPtr->procPtr == NULL)) {
	return TCL_ERROR;
    }

    /*
     * Make sure the variable names, if any, have no substitutions and just
     * refer to local scalars.
     */

    resultIndex = optsIndex = -1;
    cmdTokenPtr = TokenAfter(parsePtr->tokenPtr);
    if (parsePtr->numWords >= 3) {
	resultNameTokenPtr = TokenAfter(cmdTokenPtr);
	/* DGP */
	if (resultNameTokenPtr->type == TCL_TOKEN_SIMPLE_WORD) {
	    name = resultNameTokenPtr[1].start;
	    nameChars = resultNameTokenPtr[1].size;
	    if (!TclIsLocalScalar(name, nameChars)) {
		return TCL_ERROR;
	    }
	    resultIndex = TclFindCompiledLocal(resultNameTokenPtr[1].start,
		    resultNameTokenPtr[1].size, /*create*/ 1, VAR_SCALAR,
		    envPtr->procPtr);
	} else {
	    return TCL_ERROR;
	}
	/* DKF */
	if (parsePtr->numWords == 4) {
	    optsNameTokenPtr = TokenAfter(resultNameTokenPtr);
	    if (optsNameTokenPtr->type != TCL_TOKEN_SIMPLE_WORD) {
		return TCL_ERROR;
	    }
	    name = optsNameTokenPtr[1].start;
	    nameChars = optsNameTokenPtr[1].size;
	    if (!TclIsLocalScalar(name, nameChars)) {
		return TCL_ERROR;
	    }
	    optsIndex = TclFindCompiledLocal(optsNameTokenPtr[1].start,
		    optsNameTokenPtr[1].size, /*create*/ 1, VAR_SCALAR,
		    envPtr->procPtr);
	}
    }

    /*
     * We will compile the catch command. Emit a beginCatch instruction at the
     * start of the catch body: the subcommand it controls.
     */

    range = DeclareExceptionRange(envPtr, CATCH_EXCEPTION_RANGE);
    TclEmitInstInt4(INST_BEGIN_CATCH4, range, envPtr);

    /*
     * If the body is a simple word, compile the instructions to eval it.
     * Otherwise, compile instructions to substitute its text without
     * catching, a catch instruction that resets the stack to what it was
     * before substituting the body, and then an instruction to eval the body.
     * Care has to be taken to register the correct startOffset for the catch
     * range so that errors in the substitution are not catched [Bug 219184]
     */

    if (cmdTokenPtr->type == TCL_TOKEN_SIMPLE_WORD) {
	ExceptionRangeStarts(envPtr, range);
	CompileBody(envPtr, cmdTokenPtr, interp);
	ExceptionRangeEnds(envPtr, range);
    } else {
	CompileTokens(envPtr, cmdTokenPtr, interp);
	ExceptionRangeStarts(envPtr, range);
	TclEmitOpcode(INST_EVAL_STK, envPtr);
	ExceptionRangeEnds(envPtr, range);
    }

    /*
     * The "no errors" epilogue code: store the body's result into the
     * variable (if any), push "0" (TCL_OK) as the catch's "no error" result,
     * and jump around the "error case" code. Note that we issue the push of
     * the return options first so that if alterations happen to the current
     * interpreter state during the writing of the variable, we won't see
     * them; this results in a slightly complex instruction issuing flow
     * (can't exchange, only duplicate and pop).
     */

    if (resultIndex != -1) {
	if (optsIndex != -1) {
	    TclEmitOpcode(INST_PUSH_RETURN_OPTIONS, envPtr);
	    TclEmitInstInt4(INST_OVER, 1, envPtr);
	}
	if (resultIndex <= 255) {
	    TclEmitInstInt1(INST_STORE_SCALAR1, resultIndex, envPtr);
	} else {
	    TclEmitInstInt4(INST_STORE_SCALAR4, resultIndex, envPtr);
	}
	if (optsIndex != -1) {
	    TclEmitOpcode(INST_POP, envPtr);
	    if (optsIndex <= 255) {
		TclEmitInstInt1(INST_STORE_SCALAR1, optsIndex, envPtr);
	    } else {
		TclEmitInstInt4(INST_STORE_SCALAR4, optsIndex, envPtr);
	    }
	    TclEmitOpcode(INST_POP, envPtr);
	}
    }
    TclEmitOpcode(INST_POP, envPtr);
    PushLiteral(envPtr, "0", 1);
    TclEmitForwardJump(envPtr, TCL_UNCONDITIONAL_JUMP, &jumpFixup);

    /*
     * The "error case" code: store the body's result into the variable (if
     * any), then push the error result code. The initial PC offset here is
     * the catch's error target. Note that if we are saving the return
     * options, we do that first so the preservation cannot get affected by
     * any intermediate result handling.
     */

    envPtr->currStackDepth = savedStackDepth;
    ExceptionRangeTarget(envPtr, range, catchOffset);
    if (resultIndex != -1) {
	if (optsIndex != -1) {
	    TclEmitOpcode(INST_PUSH_RETURN_OPTIONS, envPtr);
	}
	TclEmitOpcode(INST_PUSH_RESULT, envPtr);
	if (resultIndex <= 255) {
	    TclEmitInstInt1(INST_STORE_SCALAR1, resultIndex, envPtr);
	} else {
	    TclEmitInstInt4(INST_STORE_SCALAR4, resultIndex, envPtr);
	}
	TclEmitOpcode(INST_POP, envPtr);
	if (optsIndex != -1) {
	    if (optsIndex <= 255) {
		TclEmitInstInt1(INST_STORE_SCALAR1, optsIndex, envPtr);
	    } else {
		TclEmitInstInt4(INST_STORE_SCALAR4, optsIndex, envPtr);
	    }
	    TclEmitOpcode(INST_POP, envPtr);
	}
    }
    TclEmitOpcode(INST_PUSH_RETURN_CODE, envPtr);

    /*
     * Update the target of the jump after the "no errors" code, then emit an
     * endCatch instruction at the end of the catch command.
     */

    if (TclFixupForwardJumpToHere(envPtr, &jumpFixup, 127)) {
	Tcl_Panic("TclCompileCatchCmd: bad jump distance %d\n",
		CurrentOffset(envPtr) - jumpFixup.codeOffset);
    }
    TclEmitOpcode(INST_END_CATCH, envPtr);

    envPtr->currStackDepth = savedStackDepth + 1;
    envPtr->exceptDepth--;
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCompileContinueCmd --
 *
 *	Procedure called to compile the "continue" command.
 *
 * Results:
 * 	Returns TCL_OK for a successful compile. Returns TCL_ERROR to defer
 * 	evaluation to runtime.
 *
 * Side effects:
 *	Instructions are added to envPtr to execute the "continue" command at
 *	runtime.
 *
 *----------------------------------------------------------------------
 */

int
TclCompileContinueCmd(
    Tcl_Interp *interp,		/* Used for error reporting. */
    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
				 * created by Tcl_ParseCommand. */
    CompileEnv *envPtr)		/* Holds resulting instructions. */
{
    /*
     * There should be no argument after the "continue".
     */

    if (parsePtr->numWords != 1) {
	return TCL_ERROR;
    }

    /*
     * Emit a continue instruction.
     */

    TclEmitOpcode(INST_CONTINUE, envPtr);
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCompileDictCmd --
 *
 *	Procedure called to compile the "dict" command.
 *
 * Results:
 * 	Returns TCL_OK for a successful compile. Returns TCL_ERROR to defer
 * 	evaluation to runtime.
 *
 * Side effects:
 *	Instructions are added to envPtr to execute the "dict" command at
 *	runtime.
 *
 *----------------------------------------------------------------------
 */

int
TclCompileDictCmd(
    Tcl_Interp *interp,		/* Used for error reporting. */
    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
				 * created by Tcl_ParseCommand. */
    CompileEnv *envPtr)		/* Holds resulting instructions. */
{
    Tcl_Token *tokenPtr;
    int numWords, size, i;
    const char *cmd;
    Proc *procPtr = envPtr->procPtr;

    /*
     * There must be at least one argument after the command.
     */

    if (parsePtr->numWords < 2) {
	return TCL_ERROR;
    }

    tokenPtr = TokenAfter(parsePtr->tokenPtr);
    numWords = parsePtr->numWords-2;
    if (tokenPtr->type != TCL_TOKEN_SIMPLE_WORD) {
	return TCL_ERROR;
    }

    /*
     * The following commands are in fairly common use and are possibly worth
     * bytecoding:
     *     dict append
     *     dict create	[*]
     *     dict exists	[*]
     *     dict for
     *     dict get	[*]
     *     dict incr
     *     dict keys	[*]
     *     dict lappend
     *     dict set
     *     dict unset
     * In practice, those that are pure-value operators (marked with [*]) can
     * probably be left alone (except perhaps [dict get] which is very very
     * common) and [dict update] should be considered instead (really big
     * win!)
     */

    size = tokenPtr[1].size;
    cmd = tokenPtr[1].start;
    if (size==3 && strncmp(cmd, "set", 3)==0) {
	Tcl_Token *varTokenPtr;
	int dictVarIndex, nameChars;
	const char *name;

	if (numWords < 3 || procPtr == NULL) {
	    return TCL_ERROR;
	}
	varTokenPtr = TokenAfter(tokenPtr);
	tokenPtr = TokenAfter(varTokenPtr);
	if (varTokenPtr->type != TCL_TOKEN_SIMPLE_WORD) {
	    return TCL_ERROR;
	}
	name = varTokenPtr[1].start;
	nameChars = varTokenPtr[1].size;
	if (!TclIsLocalScalar(name, nameChars)) {
	    return TCL_ERROR;
	}
	dictVarIndex = TclFindCompiledLocal(name, nameChars, 1, VAR_SCALAR,
		procPtr);
	for (i=1 ; i<numWords ; i++) {
	    CompileWord(envPtr, tokenPtr, interp);
	    tokenPtr = TokenAfter(tokenPtr);
	}
	TclEmitInstInt4( INST_DICT_SET, numWords-2,		envPtr);
	TclEmitInt4(	 dictVarIndex,				envPtr);
	return TCL_OK;
    } else if (size==4 && strncmp(cmd, "incr", 4)==0) {
	Tcl_Token *varTokenPtr, *keyTokenPtr, *incrTokenPtr = NULL;
	int dictVarIndex, nameChars, incrAmount = 1;
	const char *name;

	if (numWords < 2 || numWords > 3 || procPtr == NULL) {
	    return TCL_ERROR;
	}
	varTokenPtr = TokenAfter(tokenPtr);
	keyTokenPtr = TokenAfter(varTokenPtr);
	if (numWords == 3) {
	    const char *word;
	    int numBytes, code;
	    Tcl_Obj *intObj;

	    incrTokenPtr = TokenAfter(keyTokenPtr);
	    if (incrTokenPtr->type != TCL_TOKEN_SIMPLE_WORD) {
		return TCL_ERROR;
	    }
	    word = incrTokenPtr[1].start;
	    numBytes = incrTokenPtr[1].size;

	    intObj = Tcl_NewStringObj(word, numBytes);
	    Tcl_IncrRefCount(intObj);
	    code = Tcl_GetIntFromObj(NULL, intObj, &incrAmount);
	    Tcl_DecrRefCount(intObj);
	    if (code != TCL_OK) {
		return TCL_ERROR;
	    }
	}
	if (varTokenPtr->type != TCL_TOKEN_SIMPLE_WORD) {
	    return TCL_ERROR;
	}
	name = varTokenPtr[1].start;
	nameChars = varTokenPtr[1].size;
	if (!TclIsLocalScalar(name, nameChars)) {
	    return TCL_ERROR;
	}
	dictVarIndex = TclFindCompiledLocal(name, nameChars, 1, VAR_SCALAR,
		procPtr);
	CompileWord(envPtr, keyTokenPtr, interp);
	TclEmitInstInt4( INST_DICT_INCR_IMM, incrAmount,	envPtr);
	TclEmitInt4(	 dictVarIndex,				envPtr);
	return TCL_OK;
    } else if (size==3 && strncmp(cmd, "get", 3)==0) {
	/*
	 * Only compile this because we need INST_DICT_GET anyway.
	 */
	if (numWords < 2) {
	    return TCL_ERROR;
	}
	for (i=0 ; i<numWords ; i++) {
	    tokenPtr = TokenAfter(tokenPtr);
	    CompileWord(envPtr, tokenPtr, interp);
	}
	TclEmitInstInt4(INST_DICT_GET, numWords-1, envPtr);
	return TCL_OK;
    } else if (size==3 && strncmp(cmd, "for", 3)==0) {
	Tcl_Token *varsTokenPtr, *dictTokenPtr, *bodyTokenPtr;
	int keyVarIndex, valueVarIndex, nameChars, loopRange, catchRange;
	int infoIndex, jumpDisplacement, bodyTargetOffset, doneTargetOffset;
	int endTargetOffset;
	const char **argv;
	Tcl_DString buffer;
	int savedStackDepth = envPtr->currStackDepth;

	if (numWords != 3 || procPtr == NULL) {
	    return TCL_ERROR;
	}

	varsTokenPtr = TokenAfter(tokenPtr);
	dictTokenPtr = TokenAfter(varsTokenPtr);
	bodyTokenPtr = TokenAfter(dictTokenPtr);
	if (varsTokenPtr->type != TCL_TOKEN_SIMPLE_WORD ||
		bodyTokenPtr->type != TCL_TOKEN_SIMPLE_WORD) {
	    return TCL_ERROR;
	}

	/*
	 * Check we've got a pair of variables and that they are local
	 * variables. Then extract their indices in the LVT.
	 */

	Tcl_DStringInit(&buffer);
	Tcl_DStringAppend(&buffer, varsTokenPtr[1].start,
		varsTokenPtr[1].size);
	if (Tcl_SplitList(NULL, Tcl_DStringValue(&buffer), &numWords,
		&argv) != TCL_OK) {
	    Tcl_DStringFree(&buffer);
	    return TCL_ERROR;
	}
	Tcl_DStringFree(&buffer);
	if (numWords != 2) {
	    ckfree((char *) argv);
	    return TCL_ERROR;
	}
	nameChars = strlen(argv[0]);
	if (!TclIsLocalScalar(argv[0], nameChars)) {
	    ckfree((char *) argv);
	    return TCL_ERROR;
	}
	keyVarIndex = TclFindCompiledLocal(argv[0], nameChars, 1, VAR_SCALAR,
		procPtr);
	nameChars = strlen(argv[1]);
	if (!TclIsLocalScalar(argv[1], nameChars)) {
	    ckfree((char *) argv);
	    return TCL_ERROR;
	}
	valueVarIndex = TclFindCompiledLocal(argv[1], nameChars, 1, VAR_SCALAR,
		procPtr);
	ckfree((char *) argv);

	/*
	 * Allocate a temporary variable to store the iterator reference. The
	 * variable will contain a Tcl_DictSearch reference which will be
	 * allocated by INST_DICT_FIRST and disposed when the variable is
	 * unset (at which point it should also have been finished with).
	 */

	infoIndex = TclFindCompiledLocal(NULL, 0, 1, VAR_SCALAR, procPtr);

	/*
	 * Preparation complete; issue instructions. Note that this code
	 * issues fixed-sized jumps. That simplifies things a lot!
	 *
	 * First up, get the dictionary and start the iteration. No catching
	 * of errors at this point.
	 */

	CompileWord(envPtr, dictTokenPtr, interp);
	TclEmitInstInt4( INST_DICT_FIRST, infoIndex,		envPtr);
	doneTargetOffset = CurrentOffset(envPtr);
	TclEmitInstInt4( INST_JUMP_TRUE4, 0,			envPtr);

	/*
	 * Now we catch errors from here on so that we can finalize the search
	 * started by Tcl_DictObjFirst above.
	 */

	catchRange = DeclareExceptionRange(envPtr, CATCH_EXCEPTION_RANGE);
	TclEmitInstInt4( INST_BEGIN_CATCH4, catchRange,		envPtr);
	ExceptionRangeStarts(envPtr, catchRange);

	/*
	 * Inside the iteration, write the loop variables.
	 */

	bodyTargetOffset = CurrentOffset(envPtr);
	TclEmitInstInt4( INST_STORE_SCALAR4, keyVarIndex,	envPtr);
	TclEmitOpcode(   INST_POP,				envPtr);
	TclEmitInstInt4( INST_STORE_SCALAR4, valueVarIndex,	envPtr);
	TclEmitOpcode(   INST_POP,				envPtr);

	/*
	 * Set up the loop exception targets.
	 */

	loopRange = DeclareExceptionRange(envPtr, LOOP_EXCEPTION_RANGE);
	ExceptionRangeStarts(envPtr, loopRange);

	/*
	 * Compile the loop body itself. It should be stack-neutral.
	 */

	CompileBody(envPtr, bodyTokenPtr, interp);
	envPtr->currStackDepth = savedStackDepth + 1;
	TclEmitOpcode(   INST_POP,				envPtr);
	envPtr->currStackDepth = savedStackDepth;

	/*
	 * Both exception target ranges (error and loop) end here.
	 */

	ExceptionRangeEnds(envPtr, loopRange);
	ExceptionRangeEnds(envPtr, catchRange);

	/*
	 * Continue (or just normally process) by getting the next pair of
	 * items from the dictionary and jumping back to the code to write
	 * them into variables if there is another pair.
	 */

	ExceptionRangeTarget(envPtr, loopRange, continueOffset);
	TclEmitInstInt4( INST_DICT_NEXT, infoIndex,		envPtr);
	jumpDisplacement = bodyTargetOffset - CurrentOffset(envPtr);
	TclEmitInstInt4( INST_JUMP_FALSE4, jumpDisplacement,	envPtr);

	/*
	 * Otherwise we're done (the jump after the DICT_FIRST points here)
	 * and we need to pop the bogus key/value pair (pushed to keep stack
	 * calculations easy!)
	 */

	jumpDisplacement = CurrentOffset(envPtr) - doneTargetOffset;
	TclUpdateInstInt4AtPc(INST_JUMP_TRUE4, jumpDisplacement,
		envPtr->codeStart + doneTargetOffset);
	TclEmitOpcode(   INST_POP,				envPtr);
	TclEmitOpcode(   INST_POP,				envPtr);

	/*
	 * Now do the final cleanup for the no-error case (this is where we
	 * break out of the loop to) by force-terminating the iteration (if
	 * not already terminated), ditching the exception info and jumping to
	 * the last instruction for this command. In theory, this could be
	 * done using the "finally" clause (next generated) but this is
	 * faster.
	 */

	ExceptionRangeTarget(envPtr, loopRange, breakOffset);
	TclEmitInstInt4( INST_DICT_DONE, infoIndex,		envPtr);
	TclEmitOpcode(	 INST_END_CATCH,			envPtr);
	endTargetOffset = CurrentOffset(envPtr);
	TclEmitInstInt4( INST_JUMP4, 0,				envPtr);

	/*
	 * Error handler "finally" clause, which force-terminates the
	 * iteration and rethrows the error.
	 */

	ExceptionRangeTarget(envPtr, catchRange, catchOffset);
	TclEmitOpcode(   INST_PUSH_RETURN_OPTIONS,		envPtr);
	TclEmitOpcode(   INST_PUSH_RESULT,			envPtr);
	TclEmitInstInt4( INST_DICT_DONE, infoIndex,		envPtr);
	TclEmitOpcode(   INST_END_CATCH,			envPtr);
	TclEmitOpcode(   INST_RETURN_STK,			envPtr);

	/*
	 * Final stage of the command (normal case) is that we push an empty
	 * object. This is done last to promote peephole optimization when
	 * it's dropped immediately.
	 */

	jumpDisplacement = CurrentOffset(envPtr) - endTargetOffset;
	TclUpdateInstInt4AtPc(INST_JUMP4, jumpDisplacement,
		envPtr->codeStart + endTargetOffset);
	PushLiteral(envPtr, "", 0);
	envPtr->exceptDepth -= 2;
	return TCL_OK;
    } else if (size==6 && strncmp(cmd, "update", 6)==0) {
	const char *name;
	int nameChars, dictIndex, keyTmpIndex, numVars, range;
	Tcl_Token **keyTokenPtrs, *dictVarTokenPtr, *bodyTokenPtr;
	Tcl_DString localVarsLiteral;

	/*
	 * Parse the command. Expect the following:
	 *   dict update <lit(eral)> <any> <lit> ?<any> <lit> ...? <lit>
	 */

	if (numWords < 4 || numWords & 1 || procPtr == NULL) {
	    return TCL_ERROR;
	}
	numVars = numWords/2 - 1;
	dictVarTokenPtr = TokenAfter(tokenPtr);
	if (dictVarTokenPtr->type != TCL_TOKEN_SIMPLE_WORD) {
	    return TCL_ERROR;
	}
	name = dictVarTokenPtr[1].start;
	nameChars = dictVarTokenPtr[1].size;
	if (!TclIsLocalScalar(name, nameChars)) {
	    return TCL_ERROR;
	}
	dictIndex = TclFindCompiledLocal(name, nameChars, 1, VAR_SCALAR,
		procPtr);

	Tcl_DStringInit(&localVarsLiteral);
	keyTokenPtrs = (Tcl_Token **) ckalloc(sizeof(Tcl_Token*) * numVars);
	tokenPtr = TokenAfter(dictVarTokenPtr);
	for (i=0 ; i<numVars ; i++) {
	    keyTokenPtrs[i] = tokenPtr;
	    tokenPtr = TokenAfter(tokenPtr);
	    if (tokenPtr->type != TCL_TOKEN_SIMPLE_WORD) {
		Tcl_DStringFree(&localVarsLiteral);
		ckfree((char *) keyTokenPtrs);
		return TCL_ERROR;
	    }
	    name = tokenPtr[1].start;
	    nameChars = tokenPtr[1].size;
	    if (!TclIsLocalScalar(name, nameChars)) {
		Tcl_DStringFree(&localVarsLiteral);
		ckfree((char *) keyTokenPtrs);
		return TCL_ERROR;
	    } else {
		int localVar = TclFindCompiledLocal(name, nameChars, 1,
			VAR_SCALAR, procPtr);
		char buf[12];

		sprintf(buf, "%d", localVar);
		Tcl_DStringAppendElement(&localVarsLiteral, buf);
	    }
	    tokenPtr = TokenAfter(tokenPtr);
	}
	if (tokenPtr->type != TCL_TOKEN_SIMPLE_WORD) {
	    Tcl_DStringFree(&localVarsLiteral);
	    ckfree((char *) keyTokenPtrs);
	    return TCL_ERROR;
	}
	bodyTokenPtr = tokenPtr;

	keyTmpIndex = TclFindCompiledLocal(NULL, 0, 1, VAR_SCALAR, procPtr);

	for (i=0 ; i<numVars ; i++) {
	    CompileWord(envPtr, keyTokenPtrs[i], interp);
	}
	TclEmitInstInt4( INST_LIST, numVars,			envPtr);
	TclEmitInstInt4( INST_STORE_SCALAR4, keyTmpIndex,	envPtr);
	PushLiteral(envPtr, Tcl_DStringValue(&localVarsLiteral),
		Tcl_DStringLength(&localVarsLiteral));
	TclEmitInstInt4( INST_DICT_UPDATE_START, dictIndex,	envPtr);

	range = DeclareExceptionRange(envPtr, CATCH_EXCEPTION_RANGE);
	TclEmitInstInt4( INST_BEGIN_CATCH4, range,		envPtr);

	ExceptionRangeStarts(envPtr, range);
	CompileBody(envPtr, bodyTokenPtr, interp);
	ExceptionRangeEnds(envPtr, range);

	ExceptionRangeTarget(envPtr, range, catchOffset);
	TclEmitOpcode(   INST_PUSH_RETURN_OPTIONS,		envPtr);
	TclEmitOpcode(   INST_PUSH_RESULT,			envPtr);
	TclEmitOpcode(   INST_END_CATCH,			envPtr);
	envPtr->exceptDepth--;

	TclEmitInstInt4( INST_LOAD_SCALAR4, keyTmpIndex,	envPtr);
	PushLiteral(envPtr, Tcl_DStringValue(&localVarsLiteral),
		Tcl_DStringLength(&localVarsLiteral));
	/*
	 * Any literal would do, but this one is handy...
	 */
	TclEmitInstInt4( INST_STORE_SCALAR4, keyTmpIndex,	envPtr);
	TclEmitInstInt4( INST_DICT_UPDATE_END, dictIndex,	envPtr);

	TclEmitOpcode(   INST_RETURN_STK,			envPtr);

	Tcl_DStringFree(&localVarsLiteral);
	ckfree((char *) keyTokenPtrs);
	return TCL_OK;
    } else if (size==6 && strncmp(cmd, "append", 6) == 0) {
	Tcl_Token *varTokenPtr;
	int dictVarIndex, nameChars;
	const char *name;

	/*
	 * Arbirary safe limit; anyone exceeding it should stop worrying about
	 * speed quite so much. ;-)
	 */
	if (numWords < 3 || numWords > 100 || procPtr == NULL) {
	    return TCL_ERROR;
	}
	varTokenPtr = TokenAfter(tokenPtr);
	tokenPtr = TokenAfter(varTokenPtr);
	if (varTokenPtr->type != TCL_TOKEN_SIMPLE_WORD) {
	    return TCL_ERROR;
	}
	name = varTokenPtr[1].start;
	nameChars = varTokenPtr[1].size;
	if (!TclIsLocalScalar(name, nameChars)) {
	    return TCL_ERROR;
	}
	dictVarIndex = TclFindCompiledLocal(name, nameChars, 1, VAR_SCALAR,
		procPtr);
	for (i=1 ; i<numWords ; i++) {
	    CompileWord(envPtr, tokenPtr, interp);
	    tokenPtr = TokenAfter(tokenPtr);
	}
	if (numWords > 3) {
	    TclEmitInstInt1( INST_CONCAT1, numWords-2,		envPtr);
	}
	TclEmitInstInt4( INST_DICT_APPEND, dictVarIndex,	envPtr);
	return TCL_OK;
    } else if (size==7 && strncmp(cmd, "lappend", 7) == 0) {
	Tcl_Token *varTokenPtr, *keyTokenPtr, *valueTokenPtr;
	int dictVarIndex, nameChars;
	const char *name;

	if (numWords != 3 || procPtr == NULL) {
	    return TCL_ERROR;
	}
	varTokenPtr = TokenAfter(tokenPtr);
	keyTokenPtr = TokenAfter(varTokenPtr);
	valueTokenPtr = TokenAfter(keyTokenPtr);
	if (varTokenPtr->type != TCL_TOKEN_SIMPLE_WORD) {
	    return TCL_ERROR;
	}
	name = varTokenPtr[1].start;
	nameChars = varTokenPtr[1].size;
	if (!TclIsLocalScalar(name, nameChars)) {
	    return TCL_ERROR;
	}
	dictVarIndex = TclFindCompiledLocal(name, nameChars, 1, VAR_SCALAR,
		procPtr);
	CompileWord(envPtr, keyTokenPtr, interp);
	CompileWord(envPtr, valueTokenPtr, interp);
	TclEmitInstInt4( INST_DICT_LAPPEND, dictVarIndex,	envPtr);
	return TCL_OK;
    }

    /*
     * Something we do not know how to compile.
     */
    return TCL_ERROR;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCompileExprCmd --
 *
 *	Procedure called to compile the "expr" command.
 *
 * Results:
 * 	Returns TCL_OK for a successful compile. Returns TCL_ERROR to defer
 * 	evaluation to runtime.
 *
 * Side effects:
 *	Instructions are added to envPtr to execute the "expr" command at
 *	runtime.
 *
 *----------------------------------------------------------------------
 */

int
TclCompileExprCmd(
    Tcl_Interp *interp,		/* Used for error reporting. */
    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
				 * created by Tcl_ParseCommand. */
    CompileEnv *envPtr)		/* Holds resulting instructions. */
{
    Tcl_Token *firstWordPtr;

    if (parsePtr->numWords == 1) {
	return TCL_ERROR;
    }

    firstWordPtr = TokenAfter(parsePtr->tokenPtr);
    TclCompileExprWords(interp, firstWordPtr, parsePtr->numWords-1, envPtr);
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCompileForCmd --
 *
 *	Procedure called to compile the "for" command.
 *
 * Results:
 * 	Returns TCL_OK for a successful compile. Returns TCL_ERROR to defer
 * 	evaluation to runtime.
 *
 * Side effects:
 *	Instructions are added to envPtr to execute the "for" command at
 *	runtime.
 *
 *----------------------------------------------------------------------
 */

int
TclCompileForCmd(
    Tcl_Interp *interp,		/* Used for error reporting. */
    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
				 * created by Tcl_ParseCommand. */
    CompileEnv *envPtr)		/* Holds resulting instructions. */
{
    Tcl_Token *startTokenPtr, *testTokenPtr, *nextTokenPtr, *bodyTokenPtr;
    JumpFixup jumpEvalCondFixup;
    int testCodeOffset, bodyCodeOffset, nextCodeOffset, jumpDist;
    int bodyRange, nextRange;
    int savedStackDepth = envPtr->currStackDepth;

    if (parsePtr->numWords != 5) {
	return TCL_ERROR;
    }

    /*
     * If the test expression requires substitutions, don't compile the for
     * command inline. E.g., the expression might cause the loop to never
     * execute or execute forever, as in "for {} "$x > 5" {incr x} {}".
     */

    startTokenPtr = TokenAfter(parsePtr->tokenPtr);
    testTokenPtr = TokenAfter(startTokenPtr);
    if (testTokenPtr->type != TCL_TOKEN_SIMPLE_WORD) {
	return TCL_ERROR;
    }

    /*
     * Bail out also if the body or the next expression require substitutions
     * in order to insure correct behaviour [Bug 219166]
     */

    nextTokenPtr = TokenAfter(testTokenPtr);
    bodyTokenPtr = TokenAfter(nextTokenPtr);
    if ((nextTokenPtr->type != TCL_TOKEN_SIMPLE_WORD)
	    || (bodyTokenPtr->type != TCL_TOKEN_SIMPLE_WORD)) {
	return TCL_ERROR;
    }

    /*
     * Create ExceptionRange records for the body and the "next" command. The
     * "next" command's ExceptionRange supports break but not continue (and
     * has a -1 continueOffset).
     */

    bodyRange = DeclareExceptionRange(envPtr, LOOP_EXCEPTION_RANGE);
    nextRange = TclCreateExceptRange(LOOP_EXCEPTION_RANGE, envPtr);

    /*
     * Inline compile the initial command.
     */

    CompileBody(envPtr, startTokenPtr, interp);
    TclEmitOpcode(INST_POP, envPtr);

    /*
     * Jump to the evaluation of the condition. This code uses the "loop
     * rotation" optimisation (which eliminates one branch from the loop).
     * "for start cond next body" produces then:
     *       start
     *       goto A
     *    B: body                : bodyCodeOffset
     *       next                : nextCodeOffset, continueOffset
     *    A: cond -> result      : testCodeOffset
     *       if (result) goto B
     */

    TclEmitForwardJump(envPtr, TCL_UNCONDITIONAL_JUMP, &jumpEvalCondFixup);

    /*
     * Compile the loop body.
     */

    bodyCodeOffset = ExceptionRangeStarts(envPtr, bodyRange);
    CompileBody(envPtr, bodyTokenPtr, interp);
    ExceptionRangeEnds(envPtr, bodyRange);
    envPtr->currStackDepth = savedStackDepth + 1;
    TclEmitOpcode(INST_POP, envPtr);


    /*
     * Compile the "next" subcommand.
     */

    envPtr->currStackDepth = savedStackDepth;
    nextCodeOffset = ExceptionRangeStarts(envPtr, nextRange);
    CompileBody(envPtr, nextTokenPtr, interp);
    ExceptionRangeEnds(envPtr, nextRange);
    envPtr->currStackDepth = savedStackDepth + 1;
    TclEmitOpcode(INST_POP, envPtr);
    envPtr->currStackDepth = savedStackDepth;

    /*
     * Compile the test expression then emit the conditional jump that
     * terminates the for.
     */

    testCodeOffset = CurrentOffset(envPtr);

    jumpDist = testCodeOffset - jumpEvalCondFixup.codeOffset;
    if (TclFixupForwardJump(envPtr, &jumpEvalCondFixup, jumpDist, 127)) {
	bodyCodeOffset += 3;
	nextCodeOffset += 3;
	testCodeOffset += 3;
    }

    envPtr->currStackDepth = savedStackDepth;
    TclCompileExprWords(interp, testTokenPtr, 1, envPtr);
    envPtr->currStackDepth = savedStackDepth + 1;

    jumpDist = CurrentOffset(envPtr) - bodyCodeOffset;
    if (jumpDist > 127) {
	TclEmitInstInt4(INST_JUMP_TRUE4, -jumpDist, envPtr);
    } else {
	TclEmitInstInt1(INST_JUMP_TRUE1, -jumpDist, envPtr);
    }

    /*
     * Fix the starting points of the exception ranges (may have moved due to
     * jump type modification) and set where the exceptions target.
     */

    envPtr->exceptArrayPtr[bodyRange].codeOffset = bodyCodeOffset;
    envPtr->exceptArrayPtr[bodyRange].continueOffset = nextCodeOffset;

    envPtr->exceptArrayPtr[nextRange].codeOffset = nextCodeOffset;

    ExceptionRangeTarget(envPtr, bodyRange, breakOffset);
    ExceptionRangeTarget(envPtr, nextRange, breakOffset);

    /*
     * The for command's result is an empty string.
     */

    envPtr->currStackDepth = savedStackDepth;
    PushLiteral(envPtr, "", 0);

    envPtr->exceptDepth--;
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCompileForeachCmd --
 *
 *	Procedure called to compile the "foreach" command.
 *
 * Results:
 * 	Returns TCL_OK for a successful compile. Returns TCL_ERROR to defer
 * 	evaluation to runtime.
 *
 * Side effects:
 *	Instructions are added to envPtr to execute the "foreach" command at
 *	runtime.
 *
n*----------------------------------------------------------------------
 */

int
TclCompileForeachCmd(
    Tcl_Interp *interp,		/* Used for error reporting. */
    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
				 * created by Tcl_ParseCommand. */
    CompileEnv *envPtr)		/* Holds resulting instructions. */
{
    Proc *procPtr = envPtr->procPtr;
    ForeachInfo *infoPtr;	/* Points to the structure describing this
				 * foreach command. Stored in a AuxData
				 * record in the ByteCode. */
    int firstValueTemp;		/* Index of the first temp var in the frame
				 * used to point to a value list. */
    int loopCtTemp;		/* Index of temp var holding the loop's
				 * iteration count. */
    Tcl_Token *tokenPtr, *bodyTokenPtr;
    unsigned char *jumpPc;
    JumpFixup jumpFalseFixup;
    int jumpBackDist, jumpBackOffset, infoIndex, range;
    int numWords, numLists, numVars, loopIndex, tempVar, i, j, code;
    int savedStackDepth = envPtr->currStackDepth;

    /*
     * We parse the variable list argument words and create two arrays:
     *    varcList[i] is number of variables in i-th var list
     *    varvList[i] points to array of var names in i-th var list
     */

#define STATIC_VAR_LIST_SIZE 5
    int varcListStaticSpace[STATIC_VAR_LIST_SIZE];
    CONST char **varvListStaticSpace[STATIC_VAR_LIST_SIZE];
    int *varcList = varcListStaticSpace;
    CONST char ***varvList = varvListStaticSpace;

    /*
     * If the foreach command isn't in a procedure, don't compile it inline:
     * the payoff is too small.
     */

    if (procPtr == NULL) {
	return TCL_ERROR;
    }

    numWords = parsePtr->numWords;
    if ((numWords < 4) || (numWords%2 != 0)) {
	return TCL_ERROR;
    }

    /*
     * Bail out if the body requires substitutions in order to insure correct
     * behaviour [Bug 219166]
     */
    for (i = 0, tokenPtr = parsePtr->tokenPtr; i < numWords-1; i++) {
	tokenPtr = TokenAfter(tokenPtr);
    }
    bodyTokenPtr = tokenPtr;
    if (bodyTokenPtr->type != TCL_TOKEN_SIMPLE_WORD) {
	return TCL_ERROR;
    }

    /*
     * Allocate storage for the varcList and varvList arrays if necessary.
     */

    numLists = (numWords - 2)/2;
    if (numLists > STATIC_VAR_LIST_SIZE) {
	varcList = (int *) ckalloc(numLists * sizeof(int));
	varvList = (CONST char ***) ckalloc(numLists * sizeof(CONST char **));
    }
    for (loopIndex = 0;  loopIndex < numLists;  loopIndex++) {
	varcList[loopIndex] = 0;
	varvList[loopIndex] = NULL;
    }

    /*
     * Break up each var list and set the varcList and varvList arrays. Don't
     * compile the foreach inline if any var name needs substitutions or isn't
     * a scalar, or if any var list needs substitutions.
     */

    loopIndex = 0;
    for (i = 0, tokenPtr = parsePtr->tokenPtr;
	    i < numWords-1;
	    i++, tokenPtr = TokenAfter(tokenPtr)) {
	Tcl_DString varList;

	if (i%2 != 1) {
	    continue;
	}
	if (tokenPtr->type != TCL_TOKEN_SIMPLE_WORD) {
	    code = TCL_ERROR;
	    goto done;
	}

	/*
	 * Lots of copying going on here. Need a ListObj wizard to show a
	 * better way.
	 */

	Tcl_DStringInit(&varList);
	Tcl_DStringAppend(&varList, tokenPtr[1].start, tokenPtr[1].size);
	code = Tcl_SplitList(interp, Tcl_DStringValue(&varList),
		&varcList[loopIndex], &varvList[loopIndex]);
	Tcl_DStringFree(&varList);
	if (code != TCL_OK) {
	    code = TCL_ERROR;
	    goto done;
	}
	numVars = varcList[loopIndex];
	for (j = 0;  j < numVars;  j++) {
	    CONST char *varName = varvList[loopIndex][j];
	    if (!TclIsLocalScalar(varName, (int) strlen(varName))) {
		code = TCL_ERROR;
		goto done;
	    }
	}
	loopIndex++;
    }

    /*
     * We will compile the foreach command. Reserve (numLists + 1) temporary
     * variables:
     *    - numLists temps to hold each value list
     *    - 1 temp for the loop counter (index of next element in each list)
     *
     * At this time we don't try to reuse temporaries; if there are two
     * nonoverlapping foreach loops, they don't share any temps.
     */

    code = TCL_OK;
    firstValueTemp = -1;
    for (loopIndex = 0;  loopIndex < numLists;  loopIndex++) {
	tempVar = TclFindCompiledLocal(NULL, /*nameChars*/ 0,
		/*create*/ 1, VAR_SCALAR, procPtr);
	if (loopIndex == 0) {
	    firstValueTemp = tempVar;
	}
    }
    loopCtTemp = TclFindCompiledLocal(NULL, /*nameChars*/ 0,
	    /*create*/ 1, VAR_SCALAR, procPtr);

    /*
     * Create and initialize the ForeachInfo and ForeachVarList data
     * structures describing this command. Then create a AuxData record
     * pointing to the ForeachInfo structure.
     */

    infoPtr = (ForeachInfo *) ckalloc((unsigned)
	    sizeof(ForeachInfo) + numLists*sizeof(ForeachVarList *));
    infoPtr->numLists = numLists;
    infoPtr->firstValueTemp = firstValueTemp;
    infoPtr->loopCtTemp = loopCtTemp;
    for (loopIndex = 0;  loopIndex < numLists;  loopIndex++) {
	ForeachVarList *varListPtr;
	numVars = varcList[loopIndex];
	varListPtr = (ForeachVarList *) ckalloc((unsigned)
		sizeof(ForeachVarList) + numVars*sizeof(int));
	varListPtr->numVars = numVars;
	for (j = 0;  j < numVars;  j++) {
	    CONST char *varName = varvList[loopIndex][j];
	    int nameChars = strlen(varName);
	    varListPtr->varIndexes[j] = TclFindCompiledLocal(varName,
		    nameChars, /*create*/ 1, VAR_SCALAR, procPtr);
	}
	infoPtr->varLists[loopIndex] = varListPtr;
    }
    infoIndex = TclCreateAuxData((ClientData) infoPtr, &tclForeachInfoType, envPtr);

    /*
     * Create an exception record to handle [break] and [continue].
     */

    range = DeclareExceptionRange(envPtr, LOOP_EXCEPTION_RANGE);

    /*
     * Evaluate then store each value list in the associated temporary.
     */

    loopIndex = 0;
    for (i = 0, tokenPtr = parsePtr->tokenPtr;
	    i < numWords-1;
	    i++, tokenPtr = TokenAfter(tokenPtr)) {
	if ((i%2 == 0) && (i > 0)) {
	    CompileTokens(envPtr, tokenPtr, interp);
	    tempVar = (firstValueTemp + loopIndex);
	    if (tempVar <= 255) {
		TclEmitInstInt1(INST_STORE_SCALAR1, tempVar, envPtr);
	    } else {
		TclEmitInstInt4(INST_STORE_SCALAR4, tempVar, envPtr);
	    }
	    TclEmitOpcode(INST_POP, envPtr);
	    loopIndex++;
	}
    }

    /*
     * Initialize the temporary var that holds the count of loop iterations.
     */

    TclEmitInstInt4(INST_FOREACH_START4, infoIndex, envPtr);

    /*
     * Top of loop code: assign each loop variable and check whether
     * to terminate the loop.
     */

    ExceptionRangeTarget(envPtr, range, continueOffset);
    TclEmitInstInt4(INST_FOREACH_STEP4, infoIndex, envPtr);
    TclEmitForwardJump(envPtr, TCL_FALSE_JUMP, &jumpFalseFixup);

    /*
     * Inline compile the loop body.
     */

    ExceptionRangeStarts(envPtr, range);
    CompileBody(envPtr, bodyTokenPtr, interp);
    ExceptionRangeEnds(envPtr, range);
    envPtr->currStackDepth = savedStackDepth + 1;
    TclEmitOpcode(INST_POP, envPtr);

    /*
     * Jump back to the test at the top of the loop. Generate a 4 byte jump if
     * the distance to the test is > 120 bytes. This is conservative and
     * ensures that we won't have to replace this jump if we later need to
     * replace the ifFalse jump with a 4 byte jump.
     */

    jumpBackOffset = CurrentOffset(envPtr);
    jumpBackDist = jumpBackOffset-envPtr->exceptArrayPtr[range].continueOffset;
    if (jumpBackDist > 120) {
	TclEmitInstInt4(INST_JUMP4, -jumpBackDist, envPtr);
    } else {
	TclEmitInstInt1(INST_JUMP1, -jumpBackDist, envPtr);
    }

    /*
     * Fix the target of the jump after the foreach_step test.
     */

    if (TclFixupForwardJumpToHere(envPtr, &jumpFalseFixup, 127)) {
	/*
	 * Update the loop body's starting PC offset since it moved down.
	 */

	envPtr->exceptArrayPtr[range].codeOffset += 3;

	/*
	 * Update the jump back to the test at the top of the loop since it
	 * also moved down 3 bytes.
	 */

	jumpBackOffset += 3;
	jumpPc = (envPtr->codeStart + jumpBackOffset);
	jumpBackDist += 3;
	if (jumpBackDist > 120) {
	    TclUpdateInstInt4AtPc(INST_JUMP4, -jumpBackDist, jumpPc);
	} else {
	    TclUpdateInstInt1AtPc(INST_JUMP1, -jumpBackDist, jumpPc);
	}
    }

    /*
     * Set the loop's break target.
     */

    ExceptionRangeTarget(envPtr, range, breakOffset);

    /*
     * The foreach command's result is an empty string.
     */

    envPtr->currStackDepth = savedStackDepth;
    PushLiteral(envPtr, "", 0);
    envPtr->currStackDepth = savedStackDepth + 1;

  done:
    for (loopIndex = 0;  loopIndex < numLists;  loopIndex++) {
	if (varvList[loopIndex] != NULL) {
	    ckfree((char *) varvList[loopIndex]);
	}
    }
    if (varcList != varcListStaticSpace) {
	ckfree((char *) varcList);
	ckfree((char *) varvList);
    }
    envPtr->exceptDepth--;
    return code;
}

/*
 *----------------------------------------------------------------------
 *
 * DupForeachInfo --
 *
 *	This procedure duplicates a ForeachInfo structure created as auxiliary
 *	data during the compilation of a foreach command.
 *
 * Results:
 *	A pointer to a newly allocated copy of the existing ForeachInfo
 *	structure is returned.
 *
 * Side effects:
 *	Storage for the copied ForeachInfo record is allocated. If the
 *	original ForeachInfo structure pointed to any ForeachVarList records,
 *	these structures are also copied and pointers to them are stored in
 *	the new ForeachInfo record.
 *
 *----------------------------------------------------------------------
 */

static ClientData
DupForeachInfo(
    ClientData clientData)	/* The foreach command's compilation auxiliary
				 * data to duplicate. */
{
    register ForeachInfo *srcPtr = (ForeachInfo *) clientData;
    ForeachInfo *dupPtr;
    register ForeachVarList *srcListPtr, *dupListPtr;
    int numLists = srcPtr->numLists;
    int numVars, i, j;

    dupPtr = (ForeachInfo *) ckalloc((unsigned)
	    sizeof(ForeachInfo) + numLists*sizeof(ForeachVarList *));
    dupPtr->numLists = numLists;
    dupPtr->firstValueTemp = srcPtr->firstValueTemp;
    dupPtr->loopCtTemp = srcPtr->loopCtTemp;

    for (i = 0;  i < numLists;  i++) {
	srcListPtr = srcPtr->varLists[i];
	numVars = srcListPtr->numVars;
	dupListPtr = (ForeachVarList *) ckalloc((unsigned)
		sizeof(ForeachVarList) + numVars*sizeof(int));
	dupListPtr->numVars = numVars;
	for (j = 0;  j < numVars;  j++) {
	    dupListPtr->varIndexes[j] =	srcListPtr->varIndexes[j];
	}
	dupPtr->varLists[i] = dupListPtr;
    }
    return (ClientData) dupPtr;
}

/*
 *----------------------------------------------------------------------
 *
 * FreeForeachInfo --
 *
 *	Procedure to free a ForeachInfo structure created as auxiliary data
 *	during the compilation of a foreach command.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Storage for the ForeachInfo structure pointed to by the ClientData
 *	argument is freed as is any ForeachVarList record pointed to by the
 *	ForeachInfo structure.
 *
 *----------------------------------------------------------------------
 */

static void
FreeForeachInfo(
    ClientData clientData)	/* The foreach command's compilation auxiliary
				 * data to free. */
{
    register ForeachInfo *infoPtr = (ForeachInfo *) clientData;
    register ForeachVarList *listPtr;
    int numLists = infoPtr->numLists;
    register int i;

    for (i = 0;  i < numLists;  i++) {
	listPtr = infoPtr->varLists[i];
	ckfree((char *) listPtr);
    }
    ckfree((char *) infoPtr);
}

/*
 *----------------------------------------------------------------------
 *
 * TclCompileIfCmd --
 *
 *	Procedure called to compile the "if" command.
 *
 * Results:
 * 	Returns TCL_OK for a successful compile. Returns TCL_ERROR to defer
 * 	evaluation to runtime.
 *
 * Side effects:
 *	Instructions are added to envPtr to execute the "if" command at
 *	runtime.
 *
 *----------------------------------------------------------------------
 */
int
TclCompileIfCmd(
    Tcl_Interp *interp,		/* Used for error reporting. */
    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
				 * created by Tcl_ParseCommand. */
    CompileEnv *envPtr)		/* Holds resulting instructions. */
{
    JumpFixupArray jumpFalseFixupArray;
    				/* Used to fix the ifFalse jump after each
				 * test when its target PC is determined. */
    JumpFixupArray jumpEndFixupArray;
				/* Used to fix the jump after each "then" body
				 * to the end of the "if" when that PC is
				 * determined. */
    Tcl_Token *tokenPtr, *testTokenPtr;
    int jumpFalseDist;
    int jumpIndex = 0;		/* avoid compiler warning. */
    int numWords, wordIdx, numBytes, j, code;
    CONST char *word;
    int savedStackDepth = envPtr->currStackDepth;
				/* Saved stack depth at the start of the first
				 * test; the envPtr current depth is restored
				 * to this value at the start of each test. */
    int realCond = 1;		/* set to 0 for static conditions: "if 0 {..}" */
    int boolVal;		/* value of static condition */
    int compileScripts = 1;

    /*
     * Only compile the "if" command if all arguments are simple words, in
     * order to insure correct substitution [Bug 219166]
     */

    tokenPtr = parsePtr->tokenPtr;
    wordIdx = 0;
    numWords = parsePtr->numWords;

    for (wordIdx = 0; wordIdx < numWords; wordIdx++) {
	if (tokenPtr->type != TCL_TOKEN_SIMPLE_WORD) {
	    return TCL_ERROR;
	}
	tokenPtr = TokenAfter(tokenPtr);
    }


    TclInitJumpFixupArray(&jumpFalseFixupArray);
    TclInitJumpFixupArray(&jumpEndFixupArray);
    code = TCL_OK;

    /*
     * Each iteration of this loop compiles one "if expr ?then? body" or
     * "elseif expr ?then? body" clause.
     */

    tokenPtr = parsePtr->tokenPtr;
    wordIdx = 0;
    while (wordIdx < numWords) {
	/*
	 * Stop looping if the token isn't "if" or "elseif".
	 */

	word = tokenPtr[1].start;
	numBytes = tokenPtr[1].size;
	if ((tokenPtr == parsePtr->tokenPtr)
		|| ((numBytes == 6) && (strncmp(word, "elseif", 6) == 0))) {
	    tokenPtr = TokenAfter(tokenPtr);
	    wordIdx++;
	} else {
	    break;
	}
	if (wordIdx >= numWords) {
	    code = TCL_ERROR;
	    goto done;
	}

	/*
	 * Compile the test expression then emit the conditional jump around
	 * the "then" part.
	 */

	envPtr->currStackDepth = savedStackDepth;
	testTokenPtr = tokenPtr;


	if (realCond) {
	    /*
	     * Find out if the condition is a constant.
	     */

	    Tcl_Obj *boolObj = Tcl_NewStringObj(testTokenPtr[1].start,
		    testTokenPtr[1].size);
	    Tcl_IncrRefCount(boolObj);
	    code = Tcl_GetBooleanFromObj(NULL, boolObj, &boolVal);
	    Tcl_DecrRefCount(boolObj);
	    if (code == TCL_OK) {
		/*
		 * A static condition
		 */
		realCond = 0;
		if (!boolVal) {
		    compileScripts = 0;
		}
	    } else {
		Tcl_ResetResult(interp);
		TclCompileExprWords(interp, testTokenPtr, 1, envPtr);
		if (jumpFalseFixupArray.next >= jumpFalseFixupArray.end) {
		    TclExpandJumpFixupArray(&jumpFalseFixupArray);
		}
		jumpIndex = jumpFalseFixupArray.next;
		jumpFalseFixupArray.next++;
		TclEmitForwardJump(envPtr, TCL_FALSE_JUMP,
			jumpFalseFixupArray.fixup+jumpIndex);
	    }
	    code = TCL_OK;
	}


	/*
	 * Skip over the optional "then" before the then clause.
	 */

	tokenPtr = TokenAfter(testTokenPtr);
	wordIdx++;
	if (wordIdx >= numWords) {
	    code = TCL_ERROR;
	    goto done;
	}
	if (tokenPtr->type == TCL_TOKEN_SIMPLE_WORD) {
	    word = tokenPtr[1].start;
	    numBytes = tokenPtr[1].size;
	    if ((numBytes == 4) && (strncmp(word, "then", 4) == 0)) {
		tokenPtr = TokenAfter(tokenPtr);
		wordIdx++;
		if (wordIdx >= numWords) {
		    code = TCL_ERROR;
		    goto done;
		}
	    }
	}

	/*
	 * Compile the "then" command body.
	 */

	if (compileScripts) {
	    envPtr->currStackDepth = savedStackDepth;
	    CompileBody(envPtr, tokenPtr, interp);
	}

	if (realCond) {
	    /*
	     * Jump to the end of the "if" command. Both jumpFalseFixupArray
	     * and jumpEndFixupArray are indexed by "jumpIndex".
	     */

	    if (jumpEndFixupArray.next >= jumpEndFixupArray.end) {
		TclExpandJumpFixupArray(&jumpEndFixupArray);
	    }
	    jumpEndFixupArray.next++;
	    TclEmitForwardJump(envPtr, TCL_UNCONDITIONAL_JUMP,
		    jumpEndFixupArray.fixup+jumpIndex);

	    /*
	     * Fix the target of the jumpFalse after the test. Generate a 4
	     * byte jump if the distance is > 120 bytes. This is conservative,
	     * and ensures that we won't have to replace this jump if we later
	     * also need to replace the proceeding jump to the end of the "if"
	     * with a 4 byte jump.
	     */

	    if (TclFixupForwardJumpToHere(envPtr,
		    jumpFalseFixupArray.fixup+jumpIndex, 120)) {
		/*
		 * Adjust the code offset for the proceeding jump to the end
		 * of the "if" command.
		 */

		jumpEndFixupArray.fixup[jumpIndex].codeOffset += 3;
	    }
	} else if (boolVal) {
	    /*
	     * We were processing an "if 1 {...}"; stop compiling scripts.
	     */

	    compileScripts = 0;
	} else {
	    /*
	     * We were processing an "if 0 {...}"; reset so that the rest
	     * (elseif, else) is compiled correctly.
	     */

	    realCond = 1;
	    compileScripts = 1;
	}

	tokenPtr = TokenAfter(tokenPtr);
	wordIdx++;
    }

    /*
     * Restore the current stack depth in the environment; the "else" clause
     * (or its default) will add 1 to this.
     */

    envPtr->currStackDepth = savedStackDepth;

    /*
     * Check for the optional else clause. Do not compile anything if this was
     * an "if 1 {...}" case.
     */

    if ((wordIdx < numWords) && (tokenPtr->type == TCL_TOKEN_SIMPLE_WORD)) {
	/*
	 * There is an else clause. Skip over the optional "else" word.
	 */

	word = tokenPtr[1].start;
	numBytes = tokenPtr[1].size;
	if ((numBytes == 4) && (strncmp(word, "else", 4) == 0)) {
	    tokenPtr = TokenAfter(tokenPtr);
	    wordIdx++;
	    if (wordIdx >= numWords) {
		code = TCL_ERROR;
		goto done;
	    }
	}

	if (compileScripts) {
	    /*
	     * Compile the else command body.
	     */

	    CompileBody(envPtr, tokenPtr, interp);
	}

	/*
	 * Make sure there are no words after the else clause.
	 */

	wordIdx++;
	if (wordIdx < numWords) {
	    code = TCL_ERROR;
	    goto done;
	}
    } else {
	/*
	 * No else clause: the "if" command's result is an empty string.
	 */

	if (compileScripts) {
	    PushLiteral(envPtr, "", 0);
	}
    }

    /*
     * Fix the unconditional jumps to the end of the "if" command.
     */

    for (j = jumpEndFixupArray.next;  j > 0;  j--) {
	jumpIndex = (j - 1);	/* i.e. process the closest jump first */
	if (TclFixupForwardJumpToHere(envPtr,
		jumpEndFixupArray.fixup+jumpIndex, 127)) {
	    /*
	     * Adjust the immediately preceeding "ifFalse" jump. We moved it's
	     * target (just after this jump) down three bytes.
	     */

	    unsigned char *ifFalsePc = envPtr->codeStart
		    + jumpFalseFixupArray.fixup[jumpIndex].codeOffset;
	    unsigned char opCode = *ifFalsePc;
	    if (opCode == INST_JUMP_FALSE1) {
		jumpFalseDist = TclGetInt1AtPtr(ifFalsePc + 1);
		jumpFalseDist += 3;
		TclStoreInt1AtPtr(jumpFalseDist, (ifFalsePc + 1));
	    } else if (opCode == INST_JUMP_FALSE4) {
		jumpFalseDist = TclGetInt4AtPtr(ifFalsePc + 1);
		jumpFalseDist += 3;
		TclStoreInt4AtPtr(jumpFalseDist, (ifFalsePc + 1));
	    } else {
		Tcl_Panic("TclCompileIfCmd: unexpected opcode \"%d\" updating ifFalse jump", (int) opCode);
	    }
	}
    }

    /*
     * Free the jumpFixupArray array if malloc'ed storage was used.
     */

  done:
    envPtr->currStackDepth = savedStackDepth + 1;
    TclFreeJumpFixupArray(&jumpFalseFixupArray);
    TclFreeJumpFixupArray(&jumpEndFixupArray);
    return code;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCompileIncrCmd --
 *
 *	Procedure called to compile the "incr" command.
 *
 * Results:
 * 	Returns TCL_OK for a successful compile. Returns TCL_ERROR to defer
 * 	evaluation to runtime.
 *
 * Side effects:
 *	Instructions are added to envPtr to execute the "incr" command at
 *	runtime.
 *
 *----------------------------------------------------------------------
 */

int
TclCompileIncrCmd(
    Tcl_Interp *interp,		/* Used for error reporting. */
    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
				 * created by Tcl_ParseCommand. */
    CompileEnv *envPtr)		/* Holds resulting instructions. */
{
    Tcl_Token *varTokenPtr, *incrTokenPtr;
    int simpleVarName, isScalar, localIndex, haveImmValue, immValue;

    if ((parsePtr->numWords != 2) && (parsePtr->numWords != 3)) {
	return TCL_ERROR;
    }

    varTokenPtr = TokenAfter(parsePtr->tokenPtr);

    PushVarName(interp, varTokenPtr, envPtr, TCL_NO_LARGE_INDEX|TCL_CREATE_VAR,
	    &localIndex, &simpleVarName, &isScalar);

    /*
     * If an increment is given, push it, but see first if it's a small
     * integer.
     */

    haveImmValue = 0;
    immValue = 1;
    if (parsePtr->numWords == 3) {
	incrTokenPtr = TokenAfter(varTokenPtr);
	if (incrTokenPtr->type == TCL_TOKEN_SIMPLE_WORD) {
	    CONST char *word = incrTokenPtr[1].start;
	    int numBytes = incrTokenPtr[1].size;
	    int code;
	    Tcl_Obj *intObj = Tcl_NewStringObj(word, numBytes);
	    Tcl_IncrRefCount(intObj);
	    code = Tcl_GetIntFromObj(NULL, intObj, &immValue);
	    Tcl_DecrRefCount(intObj);
	    if ((code == TCL_OK) && (-127 <= immValue) && (immValue <= 127)) {
		haveImmValue = 1;
	    }
	    if (!haveImmValue) {
		PushLiteral(envPtr, word, numBytes);
	    }
	} else {
	    CompileTokens(envPtr, incrTokenPtr, interp);
	}
    } else {			/* no incr amount given so use 1 */
	haveImmValue = 1;
    }

    /*
     * Emit the instruction to increment the variable.
     */

    if (simpleVarName) {
	if (isScalar) {
	    if (localIndex >= 0) {
		if (haveImmValue) {
		    TclEmitInstInt1(INST_INCR_SCALAR1_IMM, localIndex, envPtr);
		    TclEmitInt1(immValue, envPtr);
		} else {
		    TclEmitInstInt1(INST_INCR_SCALAR1, localIndex, envPtr);
		}
	    } else {
		if (haveImmValue) {
		    TclEmitInstInt1(INST_INCR_SCALAR_STK_IMM, immValue, envPtr);
		} else {
		    TclEmitOpcode(INST_INCR_SCALAR_STK, envPtr);
		}
	    }
	} else {
	    if (localIndex >= 0) {
		if (haveImmValue) {
		    TclEmitInstInt1(INST_INCR_ARRAY1_IMM, localIndex, envPtr);
		    TclEmitInt1(immValue, envPtr);
		} else {
		    TclEmitInstInt1(INST_INCR_ARRAY1, localIndex, envPtr);
		}
	    } else {
		if (haveImmValue) {
		    TclEmitInstInt1(INST_INCR_ARRAY_STK_IMM, immValue, envPtr);
		} else {
		    TclEmitOpcode(INST_INCR_ARRAY_STK, envPtr);
		}
	    }
	}
    } else {			/* non-simple variable name */
	if (haveImmValue) {
	    TclEmitInstInt1(INST_INCR_STK_IMM, immValue, envPtr);
	} else {
	    TclEmitOpcode(INST_INCR_STK, envPtr);
	}
    }

    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCompileLappendCmd --
 *
 *	Procedure called to compile the "lappend" command.
 *
 * Results:
 * 	Returns TCL_OK for a successful compile. Returns TCL_ERROR to defer
 * 	evaluation to runtime.
 *
 * Side effects:
 *	Instructions are added to envPtr to execute the "lappend" command at
 *	runtime.
 *
 *----------------------------------------------------------------------
 */

int
TclCompileLappendCmd(
    Tcl_Interp *interp,		/* Used for error reporting. */
    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
				 * created by Tcl_ParseCommand. */
    CompileEnv *envPtr)		/* Holds resulting instructions. */
{
    Tcl_Token *varTokenPtr;
    int simpleVarName, isScalar, localIndex, numWords;

    /*
     * If we're not in a procedure, don't compile.
     */
    if (envPtr->procPtr == NULL) {
	return TCL_ERROR;
    }

    numWords = parsePtr->numWords;
    if (numWords == 1) {
	return TCL_ERROR;
    }
    if (numWords != 3) {
	/*
	 * LAPPEND instructions currently only handle one value appends
	 */
	return TCL_ERROR;
    }

    /*
     * Decide if we can use a frame slot for the var/array name or if we
     * need to emit code to compute and push the name at runtime. We use a
     * frame slot (entry in the array of local vars) if we are compiling a
     * procedure body and if the name is simple text that does not include
     * namespace qualifiers.
     */

    varTokenPtr = TokenAfter(parsePtr->tokenPtr);

    PushVarName(interp, varTokenPtr, envPtr, TCL_CREATE_VAR,
	    &localIndex, &simpleVarName, &isScalar);

    /*
     * If we are doing an assignment, push the new value. In the no values
     * case, create an empty object.
     */

    if (numWords > 2) {
	Tcl_Token *valueTokenPtr = TokenAfter(varTokenPtr);
	CompileWord(envPtr, valueTokenPtr, interp);
    }

    /*
     * Emit instructions to set/get the variable.
     */

    /*
     * The *_STK opcodes should be refactored to make better use of existing
     * LOAD/STORE instructions.
     */
    if (simpleVarName) {
	if (isScalar) {
	    if (localIndex < 0) {
		TclEmitOpcode(INST_LAPPEND_STK, envPtr);
	    } else if (localIndex <= 255) {
		TclEmitInstInt1(INST_LAPPEND_SCALAR1, localIndex, envPtr);
	    } else {
		TclEmitInstInt4(INST_LAPPEND_SCALAR4, localIndex, envPtr);
	    }
	} else {
	    if (localIndex < 0) {
		TclEmitOpcode(INST_LAPPEND_ARRAY_STK, envPtr);
	    } else if (localIndex <= 255) {
		TclEmitInstInt1(INST_LAPPEND_ARRAY1, localIndex, envPtr);
	    } else {
		TclEmitInstInt4(INST_LAPPEND_ARRAY4, localIndex, envPtr);
	    }
	}
    } else {
	TclEmitOpcode(INST_LAPPEND_STK, envPtr);
    }

    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCompileLassignCmd --
 *
 *	Procedure called to compile the "lassign" command.
 *
 * Results:
 * 	Returns TCL_OK for a successful compile. Returns TCL_ERROR to defer
 * 	evaluation to runtime.
 *
 * Side effects:
 *	Instructions are added to envPtr to execute the "lassign" command at
 *	runtime.
 *
 *----------------------------------------------------------------------
 */

int
TclCompileLassignCmd(
    Tcl_Interp *interp,		/* Used for error reporting. */
    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
				 * created by Tcl_ParseCommand. */
    CompileEnv *envPtr)		/* Holds resulting instructions. */
{
    Tcl_Token *tokenPtr;
    int simpleVarName, isScalar, localIndex, numWords, idx;

    numWords = parsePtr->numWords;
    /*
     * Check for command syntax error, but we'll punt that to runtime
     */
    if (numWords < 3) {
	return TCL_ERROR;
    }

    /*
     * Generate code to push list being taken apart by [lassign].
     */
    tokenPtr = TokenAfter(parsePtr->tokenPtr);
    CompileWord(envPtr, tokenPtr, interp);

    /*
     * Generate code to assign values from the list to variables
     */
    for (idx=0 ; idx<numWords-2 ; idx++) {
	tokenPtr = TokenAfter(tokenPtr);

	/*
	 * Generate the next variable name
	 */
	PushVarName(interp, tokenPtr, envPtr, TCL_CREATE_VAR,
		&localIndex, &simpleVarName, &isScalar);

	/*
	 * Emit instructions to get the idx'th item out of the list value on
	 * the stack and assign it to the variable.
	 */
	if (simpleVarName) {
	    if (isScalar) {
		if (localIndex >= 0) {
		    TclEmitOpcode(INST_DUP, envPtr);
		    TclEmitInstInt4(INST_LIST_INDEX_IMM, idx, envPtr);
		    if (localIndex <= 255) {
			TclEmitInstInt1(INST_STORE_SCALAR1, localIndex, envPtr);
		    } else {
			TclEmitInstInt4(INST_STORE_SCALAR4, localIndex, envPtr);
		    }
		} else {
		    TclEmitInstInt4(INST_OVER, 1, envPtr);
		    TclEmitInstInt4(INST_LIST_INDEX_IMM, idx, envPtr);
		    TclEmitOpcode(INST_STORE_SCALAR_STK, envPtr);
		}
	    } else {
		if (localIndex >= 0) {
		    TclEmitInstInt4(INST_OVER, 1, envPtr);
		    TclEmitInstInt4(INST_LIST_INDEX_IMM, idx, envPtr);
		    if (localIndex <= 255) {
			TclEmitInstInt1(INST_STORE_ARRAY1, localIndex, envPtr);
		    } else {
			TclEmitInstInt4(INST_STORE_ARRAY4, localIndex, envPtr);
		    }
		} else {
		    TclEmitInstInt4(INST_OVER, 2, envPtr);
		    TclEmitInstInt4(INST_LIST_INDEX_IMM, idx, envPtr);
		    TclEmitOpcode(INST_STORE_ARRAY_STK, envPtr);
		}
	    }
	} else {
	    TclEmitInstInt4(INST_OVER, 1, envPtr);
	    TclEmitInstInt4(INST_LIST_INDEX_IMM, idx, envPtr);
	    TclEmitOpcode(INST_STORE_STK, envPtr);
	}
	TclEmitOpcode(INST_POP, envPtr);
    }

    /*
     * Generate code to leave the rest of the list on the stack.
     */
    TclEmitInstInt4(INST_LIST_RANGE_IMM, idx, envPtr);
    TclEmitInt4(-2, envPtr); /* -2 == "end" */

    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCompileLindexCmd --
 *
 *	Procedure called to compile the "lindex" command.
 *
 * Results:
 * 	Returns TCL_OK for a successful compile. Returns TCL_ERROR to defer
 * 	evaluation to runtime.
 *
 * Side effects:
 *	Instructions are added to envPtr to execute the "lindex" command at
 *	runtime.
 *
 *----------------------------------------------------------------------
 */

int
TclCompileLindexCmd(
    Tcl_Interp *interp,		/* Used for error reporting. */
    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
				 * created by Tcl_ParseCommand. */
    CompileEnv *envPtr)		/* Holds resulting instructions. */
{
    Tcl_Token *varTokenPtr;
    int i, numWords = parsePtr->numWords;

    /*
     * Quit if too few args
     */

    if (numWords <= 1) {
	return TCL_ERROR;
    }

    varTokenPtr = TokenAfter(parsePtr->tokenPtr);

    if ((numWords == 3) && (varTokenPtr->type == TCL_TOKEN_SIMPLE_WORD)) {
	Tcl_Obj *tmpObj;
	int idx, result;

	tmpObj = Tcl_NewStringObj(varTokenPtr[1].start, varTokenPtr[1].size);
	result = Tcl_GetIntFromObj(NULL, tmpObj, &idx);
	TclDecrRefCount(tmpObj);

	if (result == TCL_OK && idx >= 0) {
	    /*
	     * All checks have been completed, and we have exactly this
	     * construct:
	     *	 lindex <posInt> <arbitraryValue>
	     * This is best compiled as a push of the arbitrary value followed
	     * by an "immediate lindex" which is the most efficient variety.
	     */

	    varTokenPtr = TokenAfter(varTokenPtr);
	    CompileWord(envPtr, varTokenPtr, interp);
	    TclEmitInstInt4(INST_LIST_INDEX_IMM, idx, envPtr);
	    return TCL_OK;
	}

	/*
	 * If the conversion failed or the value was negative, we just keep on
	 * going with the more complex compilation.
	 */
    }

    /*
     * Push the operands onto the stack.
     */

    for (i=1 ; i<numWords ; i++) {
	CompileWord(envPtr, varTokenPtr, interp);
	varTokenPtr = TokenAfter(varTokenPtr);
    }

    /*
     * Emit INST_LIST_INDEX if objc==3, or INST_LIST_INDEX_MULTI if there are
     * multiple index args.
     */

    if (numWords == 3) {
	TclEmitOpcode(INST_LIST_INDEX, envPtr);
    } else {
 	TclEmitInstInt4(INST_LIST_INDEX_MULTI, numWords-1, envPtr);
    }

    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCompileListCmd --
 *
 *	Procedure called to compile the "list" command.
 *
 * Results:
 * 	Returns TCL_OK for a successful compile. Returns TCL_ERROR to defer
 * 	evaluation to runtime.
 *
 * Side effects:
 *	Instructions are added to envPtr to execute the "list" command at
 *	runtime.
 *
 *----------------------------------------------------------------------
 */

int
TclCompileListCmd(
    Tcl_Interp *interp,		/* Used for error reporting. */
    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
				 * created by Tcl_ParseCommand. */
    CompileEnv *envPtr)		/* Holds resulting instructions. */
{
    /*
     * If we're not in a procedure, don't compile.
     */
    if (envPtr->procPtr == NULL) {
	return TCL_ERROR;
    }

    if (parsePtr->numWords == 1) {
	/*
	 * [list] without arguments just pushes an empty object.
	 */

	PushLiteral(envPtr, "", 0);
    } else {
	/*
	 * Push the all values onto the stack.
	 */
	Tcl_Token *valueTokenPtr;
	int i, numWords;

	numWords = parsePtr->numWords;

	valueTokenPtr = TokenAfter(parsePtr->tokenPtr);
	for (i = 1; i < numWords; i++) {
	    CompileWord(envPtr, valueTokenPtr, interp);
	    valueTokenPtr = TokenAfter(valueTokenPtr);
	}
	TclEmitInstInt4(INST_LIST, numWords - 1, envPtr);
    }

    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCompileLlengthCmd --
 *
 *	Procedure called to compile the "llength" command.
 *
 * Results:
 * 	Returns TCL_OK for a successful compile. Returns TCL_ERROR to defer
 * 	evaluation to runtime.
 *
 * Side effects:
 *	Instructions are added to envPtr to execute the "llength" command at
 *	runtime.
 *
 *----------------------------------------------------------------------
 */

int
TclCompileLlengthCmd(
    Tcl_Interp *interp,		/* Used for error reporting. */
    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
				 * created by Tcl_ParseCommand. */
    CompileEnv *envPtr)		/* Holds resulting instructions. */
{
    Tcl_Token *varTokenPtr;

    if (parsePtr->numWords != 2) {
	return TCL_ERROR;
    }
    varTokenPtr = TokenAfter(parsePtr->tokenPtr);

    CompileWord(envPtr, varTokenPtr, interp);
    TclEmitOpcode(INST_LIST_LENGTH, envPtr);
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCompileLsetCmd --
 *
 *	Procedure called to compile the "lset" command.
 *
 * Results:
 * 	Returns TCL_OK for a successful compile. Returns TCL_ERROR to defer
 * 	evaluation to runtime.
 *
 * Side effects:
 *	Instructions are added to envPtr to execute the "lset" command at
 *	runtime.
 *
 * The general template for execution of the "lset" command is:
 *	(1) Instructions to push the variable name, unless the variable is
 *	    local to the stack frame.
 *	(2) If the variable is an array element, instructions to push the
 *	    array element name.
 *	(3) Instructions to push each of zero or more "index" arguments to the
 *	    stack, followed with the "newValue" element.
 *	(4) Instructions to duplicate the variable name and/or array element
 *	    name onto the top of the stack, if either was pushed at steps (1)
 *	    and (2).
 *	(5) The appropriate INST_LOAD_* instruction to place the original
 *	    value of the list variable at top of stack.
 *	(6) At this point, the stack contains:
 *		varName? arrayElementName? index1 index2 ... newValue oldList
 *	    The compiler emits one of INST_LSET_FLAT or INST_LSET_LIST
 *	    according as whether there is exactly one index element (LIST) or
 *	    either zero or else two or more (FLAT). This instruction removes
 *	    everything from the stack except for the two names and pushes the
 *	    new value of the variable.
 *	(7) Finally, INST_STORE_* stores the new value in the variable and
 *	    cleans up the stack.
 *
 *----------------------------------------------------------------------
 */

int
TclCompileLsetCmd(
    Tcl_Interp* interp,		/* Tcl interpreter for error reporting */
    Tcl_Parse* parsePtr,	/* Points to a parse structure for the
				 * command */
    CompileEnv* envPtr)		/* Holds the resulting instructions */
{
    int tempDepth;		/* Depth used for emitting one part of the
				 * code burst. */
    Tcl_Token* varTokenPtr;	/* Pointer to the Tcl_Token representing the
				 * parse of the variable name */
    int localIndex;		/* Index of var in local var table */
    int simpleVarName;		/* Flag == 1 if var name is simple */
    int isScalar;		/* Flag == 1 if scalar, 0 if array */
    int i;

    /* Check argument count */

    if (parsePtr->numWords < 3) {
	/* Fail at run time, not in compilation */
	return TCL_ERROR;
    }

    /*
     * Decide if we can use a frame slot for the var/array name or if we need
     * to emit code to compute and push the name at runtime. We use a frame
     * slot (entry in the array of local vars) if we are compiling a procedure
     * body and if the name is simple text that does not include namespace
     * qualifiers.
     */

    varTokenPtr = TokenAfter(parsePtr->tokenPtr);
    PushVarName(interp, varTokenPtr, envPtr, TCL_CREATE_VAR,
	    &localIndex, &simpleVarName, &isScalar);

    /*
     * Push the "index" args and the new element value.
     */

    for (i=2 ; i<parsePtr->numWords ; ++i) {
	varTokenPtr = TokenAfter(varTokenPtr);
	CompileWord(envPtr, varTokenPtr, interp);
    }

    /*
     * Duplicate the variable name if it's been pushed.
     */

    if (!simpleVarName || localIndex < 0) {
	if (!simpleVarName || isScalar) {
	    tempDepth = parsePtr->numWords - 2;
	} else {
	    tempDepth = parsePtr->numWords - 1;
	}
	TclEmitInstInt4(INST_OVER, tempDepth, envPtr);
    }

    /*
     * Duplicate an array index if one's been pushed
     */

    if (simpleVarName && !isScalar) {
	if (localIndex < 0) {
	    tempDepth = parsePtr->numWords - 1;
	} else {
	    tempDepth = parsePtr->numWords - 2;
	}
	TclEmitInstInt4(INST_OVER, tempDepth, envPtr);
    }

    /*
     * Emit code to load the variable's value.
     */

    if (!simpleVarName) {
	TclEmitOpcode(INST_LOAD_STK, envPtr);
    } else if (isScalar) {
	if (localIndex < 0) {
	    TclEmitOpcode(INST_LOAD_SCALAR_STK, envPtr);
	} else if (localIndex < 0x100) {
	    TclEmitInstInt1(INST_LOAD_SCALAR1, localIndex, envPtr);
	} else {
	    TclEmitInstInt4(INST_LOAD_SCALAR4, localIndex, envPtr);
	}
    } else {
	if (localIndex < 0) {
	    TclEmitOpcode(INST_LOAD_ARRAY_STK, envPtr);
	} else if (localIndex < 0x100) {
	    TclEmitInstInt1(INST_LOAD_ARRAY1, localIndex, envPtr);
	} else {
	    TclEmitInstInt4(INST_LOAD_ARRAY4, localIndex, envPtr);
	}
    }

    /*
     * Emit the correct variety of 'lset' instruction
     */

    if (parsePtr->numWords == 4) {
	TclEmitOpcode(INST_LSET_LIST, envPtr);
    } else {
	TclEmitInstInt4(INST_LSET_FLAT, parsePtr->numWords-1, envPtr);
    }

    /*
     * Emit code to put the value back in the variable
     */

    if (!simpleVarName) {
	TclEmitOpcode(INST_STORE_STK, envPtr);
    } else if (isScalar) {
	if (localIndex < 0) {
	    TclEmitOpcode(INST_STORE_SCALAR_STK, envPtr);
	} else if (localIndex < 0x100) {
	    TclEmitInstInt1(INST_STORE_SCALAR1, localIndex, envPtr);
	} else {
	    TclEmitInstInt4(INST_STORE_SCALAR4, localIndex, envPtr);
	}
    } else {
	if (localIndex < 0) {
	    TclEmitOpcode(INST_STORE_ARRAY_STK, envPtr);
	} else if (localIndex < 0x100) {
	    TclEmitInstInt1(INST_STORE_ARRAY1, localIndex, envPtr);
	} else {
	    TclEmitInstInt4(INST_STORE_ARRAY4, localIndex, envPtr);
	}
    }

    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCompileRegexpCmd --
 *
 *	Procedure called to compile the "regexp" command.
 *
 * Results:
 * 	Returns TCL_OK for a successful compile. Returns TCL_ERROR to defer
 * 	evaluation to runtime.
 *
 * Side effects:
 *	Instructions are added to envPtr to execute the "regexp" command at
 *	runtime.
 *
 *----------------------------------------------------------------------
 */

int
TclCompileRegexpCmd(
    Tcl_Interp* interp,		/* Tcl interpreter for error reporting */
    Tcl_Parse* parsePtr,	/* Points to a parse structure for the
				 * command */
    CompileEnv* envPtr)		/* Holds the resulting instructions */
{
    Tcl_Token *varTokenPtr;	/* Pointer to the Tcl_Token representing the
				 * parse of the RE or string */
    int i, len, nocase, anchorLeft, anchorRight, start;
    char *str;

    /*
     * We are only interested in compiling simple regexp cases. Currently
     * supported compile cases are:
     *   regexp ?-nocase? ?--? staticString $var
     *   regexp ?-nocase? ?--? {^staticString$} $var
     */

    if (parsePtr->numWords < 3) {
	return TCL_ERROR;
    }

    nocase = 0;
    varTokenPtr = parsePtr->tokenPtr;

    /*
     * We only look for -nocase and -- as options. Everything else gets pushed
     * to runtime execution. This is different than regexp's runtime option
     * handling, but satisfies our stricter needs.
     */

    for (i = 1; i < parsePtr->numWords - 2; i++) {
	varTokenPtr = TokenAfter(varTokenPtr);
	if (varTokenPtr->type != TCL_TOKEN_SIMPLE_WORD) {
	    /* Not a simple string - punt to runtime. */
	    return TCL_ERROR;
	}
	str = (char *) varTokenPtr[1].start;
	len = varTokenPtr[1].size;
	if ((len == 2) && (str[0] == '-') && (str[1] == '-')) {
	    i++;
	    break;
	} else if ((len > 1) && (strncmp(str,"-nocase",(unsigned)len) == 0)) {
	    nocase = 1;
	} else {
	    /* Not an option we recognize. */
	    return TCL_ERROR;
	}
    }

    if ((parsePtr->numWords - i) != 2) {
	/* We don't support capturing to variables */
	return TCL_ERROR;
    }

    /*
     * Get the regexp string. If it is not a simple string, punt to runtime.
     * If it has a '-', it could be an incorrectly formed regexp command.
     */

    varTokenPtr = TokenAfter(varTokenPtr);
    str = (char *) varTokenPtr[1].start;
    len = varTokenPtr[1].size;
    if ((varTokenPtr->type != TCL_TOKEN_SIMPLE_WORD) || (*str == '-')) {
	return TCL_ERROR;
    }

    if (len == 0) {
	/*
	 * The semantics of regexp are always match on re == "".
	 */

	PushLiteral(envPtr, "1", 1);
	return TCL_OK;
    }

    /*
     * Make a copy of the string that is null-terminated for checks which
     * require such.
     */

    str = (char *) ckalloc((unsigned) len + 1);
    strncpy(str, varTokenPtr[1].start, (size_t) len);
    str[len] = '\0';
    start = 0;

    /*
     * Check for anchored REs (ie ^foo$), so we can use string equal if
     * possible. Do not alter the start of str so we can free it correctly.
     */

    if (str[0] == '^') {
	start++;
	anchorLeft = 1;
    } else {
	anchorLeft = 0;
    }
    if ((str[len-1] == '$') && ((len == 1) || (str[len-2] != '\\'))) {
	anchorRight = 1;
	str[--len] = '\0';
    } else {
	anchorRight = 0;
    }

    /*
     * On the first (pattern) arg, check to see if any RE special characters
     * are in the word. If not, this is the same as 'string equal'.
     */

    if ((len > 1+start) && (str[start] == '.') && (str[start+1] == '*')) {
	start += 2;
	anchorLeft = 0;
    }
    if ((len > 2+start) && (str[len-3] != '\\')
	    && (str[len-2] == '.') && (str[len-1] == '*')) {
	len -= 2;
	str[len] = '\0';
	anchorRight = 0;
    }

    /*
     * Don't do anything with REs with other special chars. Also check if this
     * is a bad RE (do this at the end because it can be expensive). If so,
     * let it complain at runtime.
     */

    if ((strpbrk(str + start, "*+?{}()[].\\|^$") != NULL)
	    || (Tcl_RegExpCompile(NULL, str) == NULL)) {
	ckfree((char *) str);
	return TCL_ERROR;
    }

    if (anchorLeft && anchorRight) {
	PushLiteral(envPtr, str+start, len-start);
    } else {
	/*
	 * This needs to find the substring anywhere in the string, so use
	 * [string match] and *foo*, with appropriate anchoring.
	 */

	char *newStr = ckalloc((unsigned) len + 3);

	len -= start;
	if (anchorLeft) {
	    strncpy(newStr, str + start, (size_t) len);
	} else {
	    newStr[0] = '*';
	    strncpy(newStr + 1, str + start, (size_t) len++);
	}
	if (!anchorRight) {
	    newStr[len++] = '*';
	}
	newStr[len] = '\0';
	PushLiteral(envPtr, newStr, len);
	ckfree((char *) newStr);
    }
    ckfree((char *) str);

    /*
     * Push the string arg
     */

    varTokenPtr = TokenAfter(varTokenPtr);
    CompileWord(envPtr, varTokenPtr, interp);

    if (anchorLeft && anchorRight && !nocase) {
	TclEmitOpcode(INST_STR_EQ, envPtr);
    } else {
	TclEmitInstInt1(INST_STR_MATCH, nocase, envPtr);
    }

    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCompileReturnCmd --
 *
 *	Procedure called to compile the "return" command.
 *
 * Results:
 * 	Returns TCL_OK for a successful compile. Returns TCL_ERROR to defer
 * 	evaluation to runtime.
 *
 * Side effects:
 *	Instructions are added to envPtr to execute the "return" command at
 *	runtime.
 *
 *----------------------------------------------------------------------
 */

int
TclCompileReturnCmd(
    Tcl_Interp *interp,		/* Used for error reporting. */
    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
				 * created by Tcl_ParseCommand. */
    CompileEnv *envPtr)		/* Holds resulting instructions. */
{
    /*
     * General syntax: [return ?-option value ...? ?result?]
     * An even number of words means an explicit result argument is present.
     */
    int level, code, status = TCL_OK;
    int numWords = parsePtr->numWords;
    int explicitResult = (0 == (numWords % 2));
    int numOptionWords = numWords - 1 - explicitResult;
    Tcl_Obj *returnOpts;
    Tcl_Token *wordTokenPtr = TokenAfter(parsePtr->tokenPtr);
#define NUM_STATIC_OBJS 20
    int objc;
    Tcl_Obj *staticObjArray[NUM_STATIC_OBJS], **objv;

    /*
     * Check for special case which can always be compiled:
     *	    return -options <opts> <msg>
     * Unlike the normal [return] compilation, this version does everything at
     * runtime so it can handle arbitrary words and not just literals. Note
     * that if INST_RETURN_STK wasn't already needed for something else
     * ('finally' clause processing) this piece of code would not be present.
     */

    if ((numWords == 4) && (wordTokenPtr->type == TCL_TOKEN_SIMPLE_WORD)
	    && (wordTokenPtr[1].size == 8)
	    && (strncmp(wordTokenPtr[1].start, "-options", 8) == 0)) {
	Tcl_Token *optsTokenPtr = TokenAfter(wordTokenPtr);
	Tcl_Token *msgTokenPtr = TokenAfter(optsTokenPtr);

	CompileWord(envPtr, optsTokenPtr, interp);
	CompileWord(envPtr, msgTokenPtr, interp);
	TclEmitOpcode(INST_RETURN_STK, envPtr);
	return TCL_OK;
    }

    /*
     * Allocate some working space if needed
     */

    if (numOptionWords > NUM_STATIC_OBJS) {
	objv = (Tcl_Obj **) ckalloc(numOptionWords * sizeof(Tcl_Obj *));
    } else {
	objv = staticObjArray;
    }

    /*
     * Scan through the return options. If any are unknown at compile time,
     * there is no value in bytecompiling. Save the option values known in an
     * objv array for merging into a return options dictionary.
     */

    for (objc = 0; objc < numOptionWords; objc++) {
	objv[objc] = Tcl_NewObj();
	Tcl_IncrRefCount(objv[objc]);
	if (!TclWordKnownAtCompileTime(wordTokenPtr, objv[objc])) {
	    objc++;
	    status = TCL_ERROR;
	    goto cleanup;
	}
	wordTokenPtr = TokenAfter(wordTokenPtr);
    }
    status = TclMergeReturnOptions(interp, objc, objv,
	    &returnOpts, &code, &level);
  cleanup:
    while (--objc >= 0) {
	Tcl_DecrRefCount(objv[objc]);
    }
    if (numOptionWords > NUM_STATIC_OBJS) {
	ckfree((char *)objv);
    }
    if (TCL_ERROR == status) {
	/*
	 * Something was bogus in the return options. Clear the error message,
	 * and report back to the compiler that this must be interpreted at
	 * runtime.
	 */
	Tcl_ResetResult(interp);
	return TCL_ERROR;
    }

    /*
     * All options are known at compile time, so we're going to bytecompile.
     * Emit instructions to push the result on the stack
     */

    if (explicitResult) {
	CompileWord(envPtr, wordTokenPtr, interp);
    } else {
	/*
	 * No explict result argument, so default result is empty string.
	 */
	PushLiteral(envPtr, "", 0);
    }

    /*
     * Check for optimization: When [return] is in a proc, and there's no
     * enclosing [catch], and there are no return options, then the INST_DONE
     * instruction is equivalent, and may be more efficient.
     */

    if (numOptionWords == 0 && envPtr->procPtr != NULL) {
	/*
	 * We have default return options and we're in a proc ...
	 */
	int index = envPtr->exceptArrayNext - 1;
	int enclosingCatch = 0;
	while (index >= 0) {
	    ExceptionRange range = envPtr->exceptArrayPtr[index];
	    if ((range.type == CATCH_EXCEPTION_RANGE)
		    && (range.catchOffset == -1)) {
		enclosingCatch = 1;
		break;
	    }
	    index--;
	}
	if (!enclosingCatch) {
	    /*
	     * ... and there is no enclosing catch. Issue the maximally
	     * efficient exit instruction.
	     */
	    Tcl_DecrRefCount(returnOpts);
	    TclEmitOpcode(INST_DONE, envPtr);
	    return TCL_OK;
	}
    }

    /*
     * Could not use the optimization, so we push the return options dict, and
     * emit the INST_RETURN_IMM instruction with code and level as operands.
     */

    TclEmitPush(TclAddLiteralObj(envPtr, returnOpts, NULL), envPtr);
    TclEmitInstInt4(INST_RETURN_IMM, code, envPtr);
    TclEmitInt4(level, envPtr);
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCompileSetCmd --
 *
 *	Procedure called to compile the "set" command.
 *
 * Results:
 * 	Returns TCL_OK for a successful compile. Returns TCL_ERROR to defer
 * 	evaluation to runtime.
 *
 * Side effects:
 *	Instructions are added to envPtr to execute the "set" command at
 *	runtime.
 *
 *----------------------------------------------------------------------
 */

int
TclCompileSetCmd(
    Tcl_Interp *interp,		/* Used for error reporting. */
    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
				 * created by Tcl_ParseCommand. */
    CompileEnv *envPtr)		/* Holds resulting instructions. */
{
    Tcl_Token *varTokenPtr, *valueTokenPtr;
    int isAssignment, isScalar, simpleVarName, localIndex, numWords;

    numWords = parsePtr->numWords;
    if ((numWords != 2) && (numWords != 3)) {
	return TCL_ERROR;
    }
    isAssignment = (numWords == 3);

    /*
     * Decide if we can use a frame slot for the var/array name or if we need
     * to emit code to compute and push the name at runtime. We use a frame
     * slot (entry in the array of local vars) if we are compiling a procedure
     * body and if the name is simple text that does not include namespace
     * qualifiers.
     */

    varTokenPtr = TokenAfter(parsePtr->tokenPtr);
    PushVarName(interp, varTokenPtr, envPtr, TCL_CREATE_VAR,
	    &localIndex, &simpleVarName, &isScalar);

    /*
     * If we are doing an assignment, push the new value.
     */

    if (isAssignment) {
	valueTokenPtr = TokenAfter(varTokenPtr);
	CompileWord(envPtr, valueTokenPtr, interp);
    }

    /*
     * Emit instructions to set/get the variable.
     */

    if (simpleVarName) {
	if (isScalar) {
	    if (localIndex < 0) {
		TclEmitOpcode((isAssignment?
		        INST_STORE_SCALAR_STK : INST_LOAD_SCALAR_STK), envPtr);
	    } else if (localIndex <= 255) {
		TclEmitInstInt1((isAssignment?
			INST_STORE_SCALAR1 : INST_LOAD_SCALAR1),
			localIndex, envPtr);
	    } else {
		TclEmitInstInt4((isAssignment?
			INST_STORE_SCALAR4 : INST_LOAD_SCALAR4),
			localIndex, envPtr);
	    }
	} else {
	    if (localIndex < 0) {
		TclEmitOpcode((isAssignment?
			INST_STORE_ARRAY_STK : INST_LOAD_ARRAY_STK), envPtr);
	    } else if (localIndex <= 255) {
		TclEmitInstInt1((isAssignment?
			INST_STORE_ARRAY1 : INST_LOAD_ARRAY1),
			localIndex, envPtr);
	    } else {
		TclEmitInstInt4((isAssignment?
			INST_STORE_ARRAY4 : INST_LOAD_ARRAY4),
			localIndex, envPtr);
	    }
	}
    } else {
	TclEmitOpcode((isAssignment? INST_STORE_STK : INST_LOAD_STK), envPtr);
    }

    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCompileStringCmd --
 *
 *	Procedure called to compile the "string" command. Generally speaking,
 *	these are mostly various kinds of peephole optimizations; most string
 *	operations are handled by executing the interpreted version of the
 *	command.
 *
 * Results:
 * 	Returns TCL_OK for a successful compile. Returns TCL_ERROR to defer
 * 	evaluation to runtime.
 *
 * Side effects:
 *	Instructions are added to envPtr to execute the "string" command at
 *	runtime.
 *
 *----------------------------------------------------------------------
 */

int
TclCompileStringCmd(
    Tcl_Interp *interp,		/* Used for error reporting. */
    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
				 * created by Tcl_ParseCommand. */
    CompileEnv *envPtr)		/* Holds resulting instructions. */
{
    Tcl_Token *opTokenPtr, *varTokenPtr;
    Tcl_Obj *opObj;
    int i, index;

    static CONST char *options[] = {
	"bytelength",	"compare",	"equal",	"first",
	"index",	"is",		"last",		"length",
	"map",		"match",	"range",	"repeat",
	"replace",	"tolower",	"toupper",	"totitle",
	"trim",		"trimleft",	"trimright",
	"wordend",	"wordstart",	NULL
    };
    enum options {
	STR_BYTELENGTH,	STR_COMPARE,	STR_EQUAL,	STR_FIRST,
	STR_INDEX,	STR_IS,		STR_LAST,	STR_LENGTH,
	STR_MAP,	STR_MATCH,	STR_RANGE,	STR_REPEAT,
	STR_REPLACE,	STR_TOLOWER,	STR_TOUPPER,	STR_TOTITLE,
	STR_TRIM,	STR_TRIMLEFT,	STR_TRIMRIGHT,
	STR_WORDEND,	STR_WORDSTART
    };

    if (parsePtr->numWords < 2) {
	/* Fail at run time, not in compilation */
	return TCL_ERROR;
    }
    opTokenPtr = TokenAfter(parsePtr->tokenPtr);

    opObj = Tcl_NewStringObj(opTokenPtr->start, opTokenPtr->size);
    if (Tcl_GetIndexFromObj(interp, opObj, options, "option", 0,
	    &index) != TCL_OK) {
	Tcl_DecrRefCount(opObj);
	Tcl_ResetResult(interp);
	return TCL_ERROR;
    }
    Tcl_DecrRefCount(opObj);

    varTokenPtr = TokenAfter(opTokenPtr);

    switch ((enum options) index) {
    case STR_COMPARE:
    case STR_EQUAL:
	/*
	 * If there are any flags to the command, we can't byte compile it
	 * because the INST_STR_EQ bytecode doesn't support flags.
	 */

	if (parsePtr->numWords != 4) {
	    return TCL_ERROR;
	}

	/*
	 * Push the two operands onto the stack.
	 */

	for (i = 0; i < 2; i++) {
	    CompileWord(envPtr, varTokenPtr, interp);
	    varTokenPtr = TokenAfter(varTokenPtr);
	}

	TclEmitOpcode(((((enum options) index) == STR_COMPARE) ?
		INST_STR_CMP : INST_STR_EQ), envPtr);
	return TCL_OK;

    case STR_INDEX:
	if (parsePtr->numWords != 4) {
	    /* Fail at run time, not in compilation */
	    return TCL_ERROR;
	}

	/*
	 * Push the two operands onto the stack.
	 */

	for (i = 0; i < 2; i++) {
	    CompileWord(envPtr, varTokenPtr, interp);
	    varTokenPtr = TokenAfter(varTokenPtr);
	}

	TclEmitOpcode(INST_STR_INDEX, envPtr);
	return TCL_OK;
    case STR_MATCH: {
	int length, exactMatch = 0, nocase = 0;
	CONST char *str;

	if (parsePtr->numWords < 4 || parsePtr->numWords > 5) {
	    /* Fail at run time, not in compilation */
	    return TCL_ERROR;
	}

	if (parsePtr->numWords == 5) {
	    if (varTokenPtr->type != TCL_TOKEN_SIMPLE_WORD) {
		return TCL_ERROR;
	    }
	    str = varTokenPtr[1].start;
	    length = varTokenPtr[1].size;
	    if ((length > 1) &&
		    strncmp(str, "-nocase", (size_t) length) == 0) {
		nocase = 1;
	    } else {
		/* Fail at run time, not in compilation */
		return TCL_ERROR;
	    }
	    varTokenPtr = TokenAfter(varTokenPtr);
	}

	for (i = 0; i < 2; i++) {
	    if (varTokenPtr->type == TCL_TOKEN_SIMPLE_WORD) {
		str = varTokenPtr[1].start;
		length = varTokenPtr[1].size;
		if (!nocase && (i == 0)) {
		    /*
		     * Trivial matches can be done by 'string equal'. If
		     * -nocase was specified, we can't do this because
		     * INST_STR_EQ has no support for nocase.
		     */
		    Tcl_Obj *copy = Tcl_NewStringObj(str, length);
		    Tcl_IncrRefCount(copy);
		    exactMatch = TclMatchIsTrivial(Tcl_GetString(copy));
		    Tcl_DecrRefCount(copy);
		}
		PushLiteral(envPtr, str, length);
	    } else {
		CompileTokens(envPtr, varTokenPtr, interp);
	    }
	    varTokenPtr = TokenAfter(varTokenPtr);
	}

	if (exactMatch) {
	    TclEmitOpcode(INST_STR_EQ, envPtr);
	} else {
	    TclEmitInstInt1(INST_STR_MATCH, nocase, envPtr);
	}
	return TCL_OK;
    }
    case STR_LENGTH:
	if (parsePtr->numWords != 3) {
	    /* Fail at run time, not in compilation */
	    return TCL_ERROR;
	}

	if (varTokenPtr->type == TCL_TOKEN_SIMPLE_WORD) {
	    /*
	     * Here someone is asking for the length of a static string. Just
	     * push the actual character (not byte) length.
	     */
	    char buf[TCL_INTEGER_SPACE];
	    int len = Tcl_NumUtfChars(varTokenPtr[1].start,
		    varTokenPtr[1].size);
	    len = sprintf(buf, "%d", len);
	    PushLiteral(envPtr, buf, len);
	    return TCL_OK;
	} else {
	    CompileTokens(envPtr, varTokenPtr, interp);
	}
	TclEmitOpcode(INST_STR_LEN, envPtr);
	return TCL_OK;

    default:
	/*
	 * All other cases: compile out of line.
	 */
	return TCL_ERROR;
    }

    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCompileSwitchCmd --
 *
 *	Procedure called to compile the "switch" command.
 *
 * Results:
 * 	Returns TCL_OK for successful compile, or TCL_ERROR to defer
 * 	evaluation to runtime (either when it is too complex to get the
 * 	semantics right, or when we know for sure that it is an error but need
 * 	the error to happen at the right time).
 *
 * Side effects:
 *	Instructions are added to envPtr to execute the "switch" command at
 *	runtime.
 *
 * FIXME:
 *	Stack depths are probably not calculated correctly.
 *
 *----------------------------------------------------------------------
 */

int
TclCompileSwitchCmd(
    Tcl_Interp *interp,		/* Used for error reporting. */
    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
				 * created by Tcl_ParseCommand. */
    CompileEnv *envPtr)		/* Holds resulting instructions. */
{
    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} 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 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 noCase;			/* Has the -nocase flag been given? */
    int foundMode = 0;		/* Have we seen a mode flag yet? */
    int i;

    /*
     * Only handle the following versions:
     *   switch        -- word {pattern body ...}
     *   switch -exact -- word {pattern body ...}
     *   switch -glob  -- word {pattern body ...}
     *   switch        -- word simpleWordPattern simpleWordBody ...
     *   switch -exact -- word simpleWordPattern simpleWordBody ...
     *   switch -glob  -- word simpleWordPattern simpleWordBody ...
     * When the mode is -glob, can also handle a -nocase flag.
     *
     * First off, we don't care how the command's word was generated; we're
     * compiling it anyway! So skip it...
     */

    tokenPtr = TokenAfter(parsePtr->tokenPtr);
    numWords = parsePtr->numWords-1;

    /*
     * Check for options. There must be at least one, --, because without that
     * there is no way to statically avoid the problems you get from strings-
     * -to-be-matched that start with a - (the interpreted code falls apart if
     * it encounters them, so we punt if we *might* encounter them as that is
     * the easiest way of emulating the behaviour).
     */

    noCase = 0;
    mode = Switch_Exact;
    for (; numWords>=3 ; tokenPtr=TokenAfter(tokenPtr),numWords--) {
	register unsigned size = tokenPtr[1].size;
	register CONST char *chrs = tokenPtr[1].start;

	/*
	 * We only process literal options, and we assume that -e, -g and -n
	 * are unique prefixes of -exact, -glob and -nocase respectively (true
	 * at time of writing). Note that -exact and -glob may only be given
	 * at most once or we bail out (error case).
	 */
	if (tokenPtr->type != TCL_TOKEN_SIMPLE_WORD || size < 2) {
	    return TCL_ERROR;
	}

	if ((size <= 6) && !memcmp(chrs, "-exact", size)) {
	    if (foundMode) {
		return TCL_ERROR;
	    }
	    mode = Switch_Exact;
	    foundMode = 1;
	    continue;
	} else if ((size <= 5) && !memcmp(chrs, "-glob", size)) {
	    if (foundMode) {
		return TCL_ERROR;
	    }
	    mode = Switch_Glob;
	    foundMode = 1;
	    continue;
	} else if ((size <= 7) && !memcmp(chrs, "-nocase", size)) {
	    noCase = 1;
	    continue;
	} else if ((size == 2) && !memcmp(chrs, "--", 2)) {
	    break;
	}

	/*
	 * The switch command has many flags we cannot compile at all (e.g.
	 * all the RE-related ones) which we must have encountered. Either
	 * that or we have run off the end. The action here is the same: punt
	 * to interpreted version.
	 */

	return TCL_ERROR;
    }
    if (numWords < 3) {
	return TCL_ERROR;
    }
    tokenPtr = TokenAfter(tokenPtr);
    numWords--;
    if (noCase && (mode == Switch_Exact)) {
	/*
	 * Can't compile this case; no opcode for case-insensitive equality!
	 */
	return TCL_ERROR;
    }

    /*
     * The value to test against is going to always get pushed on the stack.
     * But not yet; we need to verify that the rest of the command is
     * compilable too.
     */

    valueTokenPtr = tokenPtr;
    tokenPtr = TokenAfter(tokenPtr);
    numWords--;

    /*
     * Build an array of tokens for the matcher terms and script bodies. Note
     * that in the case of the quoted bodies, this is tricky as we cannot use
     * copies of the string from the input token for the generated tokens (it
     * causes a crash during exception handling). When multiple tokens are
     * available at this point, this is pretty easy.
     */

    if (numWords == 1) {
	Tcl_DString bodyList;
	CONST char **argv = NULL;
	int isTokenBraced;
	CONST char *tokenStartPtr;

	/*
	 * Test that we've got a suitable body list as a simple (i.e. braced)
	 * word, and that the elements of the body are simple words too. This
	 * is really rather nasty indeed.
	 */

	if (tokenPtr->type != TCL_TOKEN_SIMPLE_WORD) {
	    return TCL_ERROR;
	}
	Tcl_DStringInit(&bodyList);
	Tcl_DStringAppend(&bodyList, tokenPtr[1].start, tokenPtr[1].size);
	if (Tcl_SplitList(NULL, Tcl_DStringValue(&bodyList), &numWords,
		&argv) != TCL_OK) {
	    Tcl_DStringFree(&bodyList);
	    return TCL_ERROR;
	}
	Tcl_DStringFree(&bodyList);

	/*
	 * Now we know what the switch arms are, we've got to see whether we
	 * can synthesize tokens for the arms. First check whether we've got a
	 * valid number of arms since we can do that now.
	 */

	if (numWords == 0 || numWords % 2) {
	    ckfree((char *) argv);
	    return TCL_ERROR;
	}

	bodyTokenArray = (Tcl_Token *) ckalloc(sizeof(Tcl_Token) * numWords);
	bodyToken = (Tcl_Token **) ckalloc(sizeof(Tcl_Token *) * numWords);

	/*
	 * Locate the start of the arms within the overall word.
	 */

	tokenStartPtr = tokenPtr[1].start;
	while (isspace(UCHAR(*tokenStartPtr))) {
	    tokenStartPtr++;
	}
	if (*tokenStartPtr == '{') {
	    tokenStartPtr++;
	    isTokenBraced = 1;
	} else {
	    isTokenBraced = 0;
	}
	for (i=0 ; i<numWords ; i++) {
	    bodyTokenArray[i].type = TCL_TOKEN_TEXT;
	    bodyTokenArray[i].start = tokenStartPtr;
	    bodyTokenArray[i].size = strlen(argv[i]);
	    bodyTokenArray[i].numComponents = 0;
	    bodyToken[i] = bodyTokenArray+i;
	    tokenStartPtr += bodyTokenArray[i].size;

	    /*
	     * Test to see if we have guessed the end of the word correctly;
	     * if not, we can't feed the real string to the sub-compilation
	     * engine, and we're then stuck and so have to punt out to doing
	     * everything at runtime.
	     */

	    if ((isTokenBraced && *(tokenStartPtr++) != '}') ||
		    (tokenStartPtr < tokenPtr[1].start+tokenPtr[1].size
		    && !isspace(UCHAR(*tokenStartPtr)))) {
		ckfree((char *) argv);
		ckfree((char *) bodyToken);
		ckfree((char *) bodyTokenArray);
		return TCL_ERROR;
	    }
	    while (isspace(UCHAR(*tokenStartPtr))) {
		tokenStartPtr++;
		if (tokenStartPtr >= tokenPtr[1].start+tokenPtr[1].size) {
		    break;
		}
	    }
	    if (*tokenStartPtr == '{') {
		tokenStartPtr++;
		isTokenBraced = 1;
	    } else {
		isTokenBraced = 0;
	    }
	}
	ckfree((char *)argv);

	/*
	 * Check that we've parsed everything we thought we were going to
	 * parse. If not, something odd is going on (I believe it is possible
	 * to defeat the code above) and we should bail out.
	 */

	if (tokenStartPtr != tokenPtr[1].start+tokenPtr[1].size) {
	    ckfree((char *) bodyToken);
	    ckfree((char *) bodyTokenArray);
	    return TCL_ERROR;
	}

    } else if (numWords % 2 || numWords == 0) {
	/*
	 * Odd number of words (>1) available, or no words at all available.
	 * Both are error cases, so punt and let the interpreted-version
	 * generate the error message. Note that the second case probably
	 * should get caught earlier, but it's easy to check here again anyway
	 * because it'd cause a nasty crash otherwise.
	 */

	return TCL_ERROR;

    } else {
	bodyToken = (Tcl_Token **) ckalloc(sizeof(Tcl_Token *) * numWords);
	bodyTokenArray = NULL;
	for (i=0 ; i<numWords ; i++) {
	    /*
	     * We only handle the very simplest case. Anything more complex is
	     * a good reason to go to the interpreted case anyway due to
	     * traces, etc.
	     */

	    if (tokenPtr->type != TCL_TOKEN_SIMPLE_WORD ||
		    tokenPtr->numComponents != 1) {
		ckfree((char *) bodyToken);
		return TCL_ERROR;
	    }
	    bodyToken[i] = tokenPtr+1;
	    tokenPtr = TokenAfter(tokenPtr);
	}
    }

    /*
     * Fall back to interpreted if the last body is a continuation (it's
     * illegal, but this makes the error happen at the right time).
     */

    if (bodyToken[numWords-1]->size == 1 &&
	    bodyToken[numWords-1]->start[0] == '-') {
	ckfree((char *) bodyToken);
	if (bodyTokenArray != NULL) {
	    ckfree((char *) bodyTokenArray);
	}
	return TCL_ERROR;
    }

    /*
     * 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.
     */

    CompileTokens(envPtr, valueTokenPtr, interp);

    /*
     * Generate a test for each arm.
     */

    contFixIndex = -1;
    contFixCount = 0;
    fixupArray = (JumpFixup *) ckalloc(sizeof(JumpFixup) * numWords);
    fixupTargetArray = (int *) ckalloc(sizeof(int) * numWords);
    memset(fixupTargetArray, 0, numWords * sizeof(int));
    fixupCount = 0;
    foundDefault = 0;
    for (i=0 ; i<numWords ; i+=2) {
	int nextArmFixupIndex = -1;
	envPtr->currStackDepth = savedStackDepth + 1;
	if (i!=numWords-2 || bodyToken[numWords-2]->size != 7 ||
		memcmp(bodyToken[numWords-2]->start, "default", 7)) {
	    /*
	     * Generate the test for the arm. This code is slightly
	     * inefficient, but much simpler than the first version.
	     */

	    TclCompileTokens(interp, bodyToken[i], 1, envPtr);
	    TclEmitInstInt4(INST_OVER, 1, envPtr);
	    switch (mode) {
	    case Switch_Exact:
		TclEmitOpcode(INST_STR_EQ, envPtr);
		break;
	    case Switch_Glob:
		TclEmitInstInt1(INST_STR_MATCH, noCase, envPtr);
		break;
	    default:
		Tcl_Panic("unknown switch mode: %d", mode);
	    }

	    /*
	     * In a fall-through case, we will jump on _true_ to the place
	     * where the body starts (generated later, with guarantee of this
	     * ensured earlier; the final body is never a fall-through).
	     */

	    if (bodyToken[i+1]->size==1 && bodyToken[i+1]->start[0]=='-') {
		if (contFixIndex == -1) {
		    contFixIndex = fixupCount;
		    contFixCount = 0;
		}
		TclEmitForwardJump(envPtr, TCL_TRUE_JUMP,
			fixupArray+contFixIndex+contFixCount);
		fixupCount++;
		contFixCount++;
		continue;
	    }

	    TclEmitForwardJump(envPtr, TCL_FALSE_JUMP, fixupArray+fixupCount);
	    nextArmFixupIndex = fixupCount;
	    fixupCount++;
	} else {
	    /*
	     * Got a default clause; set a flag to inhibit the generation of
	     * the jump after the body and the cleanup of the intermediate
	     * value that we are switching against.
	     *
	     * Note that default clauses (which are always terminal clauses)
	     * cannot be fall-through clauses as well, since the last clause
	     * is never a fall-through clause (which we have already
	     * verified).
	     */

	    foundDefault = 1;
	}

	/*
	 * Generate the body for the arm. This is guaranteed not to be a
	 * fall-through case, but it might have preceding fall-through cases,
	 * so we must process those first.
	 */

	if (contFixIndex != -1) {
	    int j;
	    for (j=0 ; j<contFixCount ; j++) {
		fixupTargetArray[contFixIndex+j] = CurrentOffset(envPtr);
	    }
	    contFixIndex = -1;
	}

	/*
	 * Now do the actual compilation. Note that we do not use CompileBody
	 * because we may have synthesized the tokens in a non-standard
	 * pattern.
	 */

	TclEmitOpcode(INST_POP, envPtr);
	envPtr->currStackDepth = savedStackDepth + 1;
	TclCompileCmdWord(interp, bodyToken[i+1], 1, envPtr);

	if (!foundDefault) {
	    TclEmitForwardJump(envPtr, TCL_UNCONDITIONAL_JUMP,
		    fixupArray+fixupCount);
	    fixupCount++;
	    fixupTargetArray[nextArmFixupIndex] = CurrentOffset(envPtr);
	}
    }
    ckfree((char *) bodyToken);
    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
     * command an empty string.
     */

    if (!foundDefault) {
	TclEmitOpcode(INST_POP, envPtr);
	PushLiteral(envPtr, "", 0);
    }

    /*
     * Do jump fixups for arms that were executed. First, fill in the jumps of
     * all jumps that don't point elsewhere to point to here.
     */

    for (i=0 ; i<fixupCount ; i++) {
	if (fixupTargetArray[i] == 0) {
	    fixupTargetArray[i] = envPtr->codeNext-envPtr->codeStart;
	}
    }

    /*
     * Now scan backwards over all the jumps (all of which are forward jumps)
     * doing each one. When we do one and there is a size changes, we must
     * scan back over all the previous ones and see if they need adjusting
     * before proceeding with further jump fixups (the interleaved nature of
     * all the jumps makes this impossible to do without nested loops).
     */

    for (i=fixupCount-1 ; i>=0 ; i--) {
	if (TclFixupForwardJump(envPtr, &fixupArray[i],
		fixupTargetArray[i] - fixupArray[i].codeOffset, 127)) {
	    int j;
	    for (j=i-1 ; j>=0 ; j--) {
		if (fixupTargetArray[j] > fixupArray[i].codeOffset) {
		    fixupTargetArray[j] += 3;
		}
	    }
	}
    }
    ckfree((char *) fixupArray);
    ckfree((char *) fixupTargetArray);

    envPtr->currStackDepth = savedStackDepth + 1;
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCompileVariableCmd --
 *
 *	Procedure called to reserve the local variables for the "variable"
 *	command. The command itself is *not* compiled.
 *
 * Results:
 *      Always returns TCL_ERROR.
 *
 * Side effects:
 *      Indexed local variables are added to the environment.
 *
 *----------------------------------------------------------------------
 */

int
TclCompileVariableCmd(
    Tcl_Interp *interp,		/* Used for error reporting. */
    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
				 * created by Tcl_ParseCommand. */
    CompileEnv *envPtr)		/* Holds resulting instructions. */
{
    Tcl_Token *varTokenPtr;
    int i, numWords;
    CONST char *varName, *tail;

    if (envPtr->procPtr == NULL) {
	return TCL_ERROR;
    }

    numWords = parsePtr->numWords;

    varTokenPtr = TokenAfter(parsePtr->tokenPtr);
    for (i = 1; i < numWords; i += 2) {
	/*
	 * Skip non-literals.
	 */
	if (varTokenPtr->type != TCL_TOKEN_SIMPLE_WORD) {
	    continue;
	}

	varName = varTokenPtr[1].start;
	tail = varName + varTokenPtr[1].size - 1;

	/*
	 * Skip if it looks like it might be an array or an empty string.
	 */
	if ((*tail == ')') || (tail < varName)) {
	    continue;
	}

	while ((tail > varName) && ((*tail != ':') || (*(tail-1) != ':'))) {
	    tail--;
	}
	if ((*tail == ':') && (tail > varName)) {
	    tail++;
	}
	(void) TclFindCompiledLocal(tail, tail-varName+1,
		/*create*/ 1, /*flags*/ 0, envPtr->procPtr);
	varTokenPtr = TokenAfter(varTokenPtr);
    }
    return TCL_ERROR;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCompileWhileCmd --
 *
 *	Procedure called to compile the "while" command.
 *
 * Results:
 * 	Returns TCL_OK for a successful compile. Returns TCL_ERROR to defer
 * 	evaluation to runtime.
 *
 * Side effects:
 *	Instructions are added to envPtr to execute the "while" command at
 *	runtime.
 *
 *----------------------------------------------------------------------
 */

int
TclCompileWhileCmd(
    Tcl_Interp *interp,		/* Used for error reporting. */
    Tcl_Parse *parsePtr,	/* Points to a parse structure for the command
				 * created by Tcl_ParseCommand. */
    CompileEnv *envPtr)		/* Holds resulting instructions. */
{
    Tcl_Token *testTokenPtr, *bodyTokenPtr;
    JumpFixup jumpEvalCondFixup;
    int testCodeOffset, bodyCodeOffset, jumpDist;
    int range, code;
    int savedStackDepth = envPtr->currStackDepth;
    int loopMayEnd = 1;		/* This is set to 0 if it is recognized as an
				 * infinite loop. */
    Tcl_Obj *boolObj;
    int boolVal;

    if (parsePtr->numWords != 3) {
	return TCL_ERROR;
    }

    /*
     * If the test expression requires substitutions, don't compile the while
     * command inline. E.g., the expression might cause the loop to never
     * execute or execute forever, as in "while "$x < 5" {}".
     *
     * Bail out also if the body expression requires substitutions in order to
     * insure correct behaviour [Bug 219166]
     */

    testTokenPtr = TokenAfter(parsePtr->tokenPtr);
    bodyTokenPtr = TokenAfter(testTokenPtr);

    if ((testTokenPtr->type != TCL_TOKEN_SIMPLE_WORD)
	    || (bodyTokenPtr->type != TCL_TOKEN_SIMPLE_WORD)) {
	return TCL_ERROR;
    }

    /*
     * Find out if the condition is a constant.
     */

    boolObj = Tcl_NewStringObj(testTokenPtr[1].start, testTokenPtr[1].size);
    Tcl_IncrRefCount(boolObj);
    code = Tcl_GetBooleanFromObj(NULL, boolObj, &boolVal);
    Tcl_DecrRefCount(boolObj);
    if (code == TCL_OK) {
	if (boolVal) {
	    /*
	     * It is an infinite loop; flag it so that we generate a more
	     * efficient body.
	     */

	    loopMayEnd = 0;
	} else {
	    /*
	     * This is an empty loop: "while 0 {...}" or such. Compile no
	     * bytecodes.
	     */

	    goto pushResult;
	}
    }

    /*
     * Create a ExceptionRange record for the loop body. This is used to
     * implement break and continue.
     */

    range = DeclareExceptionRange(envPtr, LOOP_EXCEPTION_RANGE);

    /*
     * Jump to the evaluation of the condition. This code uses the "loop
     * rotation" optimisation (which eliminates one branch from the loop).
     * "while cond body" produces then:
     *       goto A
     *    B: body                : bodyCodeOffset
     *    A: cond -> result      : testCodeOffset, continueOffset
     *       if (result) goto B
     *
     * The infinite loop "while 1 body" produces:
     *    B: body                : all three offsets here
     *       goto B
     */

    if (loopMayEnd) {
	TclEmitForwardJump(envPtr, TCL_UNCONDITIONAL_JUMP, &jumpEvalCondFixup);
	testCodeOffset = 0; /* avoid compiler warning */
    } else {
	testCodeOffset = CurrentOffset(envPtr);
    }

    /*
     * Compile the loop body.
     */

    bodyCodeOffset = ExceptionRangeStarts(envPtr, range);
    CompileBody(envPtr, bodyTokenPtr, interp);
    ExceptionRangeEnds(envPtr, range);
    envPtr->currStackDepth = savedStackDepth + 1;
    TclEmitOpcode(INST_POP, envPtr);

    /*
     * Compile the test expression then emit the conditional jump that
     * terminates the while. We already know it's a simple word.
     */

    if (loopMayEnd) {
	testCodeOffset = CurrentOffset(envPtr);
	jumpDist = testCodeOffset - jumpEvalCondFixup.codeOffset;
	if (TclFixupForwardJump(envPtr, &jumpEvalCondFixup, jumpDist, 127)) {
	    bodyCodeOffset += 3;
	    testCodeOffset += 3;
	}
	envPtr->currStackDepth = savedStackDepth;
	TclCompileExprWords(interp, testTokenPtr, 1, envPtr);
	envPtr->currStackDepth = savedStackDepth + 1;

	jumpDist = CurrentOffset(envPtr) - bodyCodeOffset;
	if (jumpDist > 127) {
	    TclEmitInstInt4(INST_JUMP_TRUE4, -jumpDist, envPtr);
	} else {
	    TclEmitInstInt1(INST_JUMP_TRUE1, -jumpDist, envPtr);
	}
    } else {
	jumpDist = CurrentOffset(envPtr) - bodyCodeOffset;
	if (jumpDist > 127) {
	    TclEmitInstInt4(INST_JUMP4, -jumpDist, envPtr);
	} else {
	    TclEmitInstInt1(INST_JUMP1, -jumpDist, envPtr);
	}
    }


    /*
     * Set the loop's body, continue and break offsets.
     */

    envPtr->exceptArrayPtr[range].continueOffset = testCodeOffset;
    envPtr->exceptArrayPtr[range].codeOffset = bodyCodeOffset;
    ExceptionRangeTarget(envPtr, range, breakOffset);

    /*
     * The while command's result is an empty string.
     */

  pushResult:
    envPtr->currStackDepth = savedStackDepth;
    PushLiteral(envPtr, "", 0);
    envPtr->exceptDepth--;
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * PushVarName --
 *
 *	Procedure used in the compiling where pushing a variable name is
 *	necessary (append, lappend, set).
 *
 * 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 "set" command at
 *	runtime.
 *
 *----------------------------------------------------------------------
 */

static int
PushVarName(
    Tcl_Interp *interp,		/* Used for error reporting. */
    Tcl_Token *varTokenPtr,	/* Points to a variable token. */
    CompileEnv *envPtr,		/* Holds resulting instructions. */
    int flags,			/* TCL_CREATE_VAR or TCL_NO_LARGE_INDEX */
    int *localIndexPtr,		/* must not be NULL */
    int *simpleVarNamePtr,	/* must not be NULL */
    int *isScalarPtr)		/* must not be NULL */
{
    register CONST char *p;
    CONST char *name, *elName;
    register int i, n;
    int nameChars, elNameChars, simpleVarName, localIndex;

    Tcl_Token *elemTokenPtr = NULL;
    int elemTokenCount = 0;
    int allocedTokens = 0;
    int removedParen = 0;

    /*
     * Decide if we can use a frame slot for the var/array name or if we need
     * to emit code to compute and push the name at runtime. We use a frame
     * slot (entry in the array of local vars) if we are compiling a procedure
     * body and if the name is simple text that does not include namespace
     * qualifiers.
     */

    simpleVarName = 0;
    name = elName = NULL;
    nameChars = elNameChars = 0;
    localIndex = -1;

    /*
     * Check not only that the type is TCL_TOKEN_SIMPLE_WORD, but whether
     * curly braces surround the variable name. This really matters for array
     * elements to handle things like
     *    set {x($foo)} 5
     * which raises an undefined var error if we are not careful here.
     */

    if ((varTokenPtr->type == TCL_TOKEN_SIMPLE_WORD) &&
	    (varTokenPtr->start[0] != '{')) {
	/*
	 * A simple variable name. Divide it up into "name" and "elName"
	 * strings. If it is not a local variable, look it up at runtime.
	 */
	simpleVarName = 1;

	name = varTokenPtr[1].start;
	nameChars = varTokenPtr[1].size;
	if (name[nameChars-1] == ')') {
	    /*
	     * last char is ')' => potential array reference.
	     */

	    for (i=0,p=name ; i<nameChars ; i++,p++) {
		if (*p == '(') {
		    elName = p + 1;
		    elNameChars = nameChars - i - 2;
		    nameChars = i;
		    break;
		}
	    }

	    if ((elName != NULL) && elNameChars) {
		/*
		 * An array element, the element name is a simple string:
		 * assemble the corresponding token.
		 */

		elemTokenPtr = (Tcl_Token *) ckalloc(sizeof(Tcl_Token));
		allocedTokens = 1;
		elemTokenPtr->type = TCL_TOKEN_TEXT;
		elemTokenPtr->start = elName;
		elemTokenPtr->size = elNameChars;
		elemTokenPtr->numComponents = 0;
		elemTokenCount = 1;
	    }
	}
    } else if (((n = varTokenPtr->numComponents) > 1)
	    && (varTokenPtr[1].type == TCL_TOKEN_TEXT)
	    && (varTokenPtr[n].type == TCL_TOKEN_TEXT)
	    && (varTokenPtr[n].start[varTokenPtr[n].size - 1] == ')')) {

	/*
	 * Check for parentheses inside first token
	 */

	simpleVarName = 0;
	for (i = 0, p = varTokenPtr[1].start;
		i < varTokenPtr[1].size; i++, p++) {
	    if (*p == '(') {
		simpleVarName = 1;
		break;
	    }
	}
	if (simpleVarName) {
	    int remainingChars;

	    /*
	     * Check the last token: if it is just ')', do not count it.
	     * Otherwise, remove the ')' and flag so that it is restored at
	     * the end.
	     */

	    if (varTokenPtr[n].size == 1) {
		--n;
	    } else {
		--varTokenPtr[n].size;
		removedParen = n;
	    }

	    name = varTokenPtr[1].start;
	    nameChars = p - varTokenPtr[1].start;
	    elName = p + 1;
	    remainingChars = (varTokenPtr[2].start - p) - 1;
	    elNameChars = (varTokenPtr[n].start - p) + varTokenPtr[n].size - 2;

	    if (remainingChars) {
		/*
		 * Make a first token with the extra characters in the first
		 * token.
		 */

		elemTokenPtr = (Tcl_Token *) ckalloc(n * sizeof(Tcl_Token));
		allocedTokens = 1;
		elemTokenPtr->type = TCL_TOKEN_TEXT;
		elemTokenPtr->start = elName;
		elemTokenPtr->size = remainingChars;
		elemTokenPtr->numComponents = 0;
		elemTokenCount = n;

		/*
		 * Copy the remaining tokens.
		 */

		memcpy((void *) (elemTokenPtr+1), (void *) (&varTokenPtr[2]),
			(n-1) * sizeof(Tcl_Token));
	    } else {
		/*
		 * Use the already available tokens.
		 */

		elemTokenPtr = &varTokenPtr[2];
		elemTokenCount = n - 1;
	    }
	}
    }

    if (simpleVarName) {
	/*
	 * See whether name has any namespace separators (::'s).
	 */

	int hasNsQualifiers = 0;
	for (i = 0, p = name;  i < nameChars;  i++, p++) {
	    if ((*p == ':') && ((i+1) < nameChars) && (*(p+1) == ':')) {
		hasNsQualifiers = 1;
		break;
	    }
	}

	/*
	 * Look up the var name's index in the array of local vars in the proc
	 * frame. If retrieving the var's value and it doesn't already exist,
	 * push its name and look it up at runtime.
	 */

	if ((envPtr->procPtr != NULL) && !hasNsQualifiers) {
	    localIndex = TclFindCompiledLocal(name, nameChars,
		    /*create*/ flags & TCL_CREATE_VAR,
		    /*flags*/ ((elName==NULL)? VAR_SCALAR : VAR_ARRAY),
		    envPtr->procPtr);
	    if ((flags & TCL_NO_LARGE_INDEX) && (localIndex > 255)) {
		/* we'll push the name */
		localIndex = -1;
	    }
	}
	if (localIndex < 0) {
	    PushLiteral(envPtr, name, nameChars);
	}

	/*
	 * Compile the element script, if any.
	 */

	if (elName != NULL) {
	    if (elNameChars) {
		TclCompileTokens(interp, elemTokenPtr, elemTokenCount, envPtr);
	    } else {
		PushLiteral(envPtr, "", 0);
	    }
	}
    } else {
	/*
	 * The var name isn't simple: compile and push it.
	 */

	CompileTokens(envPtr, varTokenPtr, interp);
    }

    if (removedParen) {
	++varTokenPtr[removedParen].size;
    }
    if (allocedTokens) {
        ckfree((char *) elemTokenPtr);
    }
    *localIndexPtr = localIndex;
    *simpleVarNamePtr = simpleVarName;
    *isScalarPtr = (elName == NULL);
    return TCL_OK;
}

/*
 * Local Variables:
 * mode: c
 * c-basic-offset: 4
 * fill-column: 78
 * End:
 */