* generic/tclCompCmds.c (TclCompileDictForCmd): Update the compilation

	* generic/tclCompile.c (tclInstructionTable):	of [dict for] so that
	* generic/tclExecute.c (TEBCresume):		it no longer makes any
	use of INST_DICT_DONE now that's not needed, and make it clearer in
	the implementation of the instruction that it's just a deprecated form
	of unset operation. Followup to my commit of 2010-10-16.

4 files changed, 46 insertions, 27 deletions

diff --git a/ChangeLog b/ChangeLog
index d07a302..95d6896 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2010-10-20  Donal K. Fellows  <dkf@users.sf.net>
+
+	* generic/tclCompCmds.c (TclCompileDictForCmd): Update the compilation
+	* generic/tclCompile.c (tclInstructionTable):	of [dict for] so that
+	* generic/tclExecute.c (TEBCresume):		it no longer makes any
+	use of INST_DICT_DONE now that's not needed, and make it clearer in
+	the implementation of the instruction that it's just a deprecated form
+	of unset operation. Followup to my commit of 2010-10-16.
+
 2010-10-19  Donal K. Fellows  <dkf@users.sf.net>
 
 	* generic/tclZlib.c (Tcl_ZlibStreamGet): [Bug 3081008]: Ensure that
diff --git a/generic/tclCompCmds.c b/generic/tclCompCmds.c
index 473dcb4..a5e1074 100644
--- a/generic/tclCompCmds.c
+++ b/generic/tclCompCmds.c
@@ -12,7 +12,7 @@
  * 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 1.169 2010/04/30 09:23:06 dkf Exp $
+ * RCS: @(#) $Id: tclCompCmds.c,v 1.170 2010/10/20 13:34:10 dkf Exp $
  */
 
 #include "tclInt.h"
@@ -876,7 +876,8 @@ TclCompileDictForCmd(
      */
 
     ExceptionRangeTarget(envPtr, loopRange, breakOffset);
-    TclEmitInstInt4( INST_DICT_DONE, infoIndex,			envPtr);
+    TclEmitInstInt1( INST_UNSET_SCALAR, 0,			envPtr);
+    TclEmitInt4(     infoIndex,					envPtr);
     TclEmitOpcode(   INST_END_CATCH,				envPtr);
     endTargetOffset = CurrentOffset(envPtr);
     TclEmitInstInt4( INST_JUMP4, 0,				envPtr);
@@ -889,7 +890,8 @@ TclCompileDictForCmd(
     ExceptionRangeTarget(envPtr, catchRange, catchOffset);
     TclEmitOpcode(   INST_PUSH_RETURN_OPTIONS,			envPtr);
     TclEmitOpcode(   INST_PUSH_RESULT,				envPtr);
-    TclEmitInstInt4( INST_DICT_DONE, infoIndex,			envPtr);
+    TclEmitInstInt1( INST_UNSET_SCALAR, 0,			envPtr);
+    TclEmitInt4(     infoIndex,					envPtr);
     TclEmitOpcode(   INST_END_CATCH,				envPtr);
     TclEmitOpcode(   INST_RETURN_STK,				envPtr);
 
@@ -905,7 +907,8 @@ TclCompileDictForCmd(
 	    envPtr->codeStart + emptyTargetOffset);
     TclEmitOpcode(   INST_POP,					envPtr);
     TclEmitOpcode(   INST_POP,					envPtr);
-    TclEmitInstInt4( INST_DICT_DONE, infoIndex,			envPtr);
+    TclEmitInstInt1( INST_UNSET_SCALAR, 0,			envPtr);
+    TclEmitInt4(     infoIndex,					envPtr);
 
     /*
      * Final stage of the command (normal case) is that we push an empty
diff --git a/generic/tclCompile.c b/generic/tclCompile.c
index dd92f27..7781066 100644
--- a/generic/tclCompile.c
+++ b/generic/tclCompile.c
@@ -11,7 +11,7 @@
  * See the file "license.terms" for information on usage and redistribution of
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclCompile.c,v 1.191 2010/10/13 17:10:57 dgp Exp $
+ * RCS: @(#) $Id: tclCompile.c,v 1.192 2010/10/20 13:34:11 dkf Exp $
  */
 
 #include "tclInt.h"
@@ -343,14 +343,16 @@ InstructionDesc const tclInstructionTable[] = {
 	 * Stack:  ... key valueToAppend => ... newDict */
     {"dictFirst",	  5,	+2,	   1,	{OPERAND_LVT4}},
 	/* Begin iterating over the dictionary, using the local scalar
-	 * indicated by op4 to hold the iterator state. If doneBool is true,
-	 * dictDone *must* be called later on.
+	 * indicated by op4 to hold the iterator state. The local scalar
+	 * should not refer to a named variable as the value is not wholly
+	 * managed correctly.
 	 * Stack:  ... dict => ... value key doneBool */
     {"dictNext",	  5,	+3,	   1,	{OPERAND_LVT4}},
 	/* Get the next iteration from the iterator in op4's local scalar.
 	 * Stack:  ... => ... value key doneBool */
     {"dictDone",	  5,	0,	   1,	{OPERAND_LVT4}},
-	/* Terminate the iterator in op4's local scalar. */
+	/* Terminate the iterator in op4's local scalar. Use unsetScalar
+	 * instead (with 0 for flags). */
     {"dictUpdateStart",   9,    0,	   2,	{OPERAND_LVT4, OPERAND_AUX4}},
 	/* Create the variables (described in the aux data referred to by the
 	 * second immediate argument) to mirror the state of the dictionary in
diff --git a/generic/tclExecute.c b/generic/tclExecute.c
index 65e0b22..5343ecd 100644
--- a/generic/tclExecute.c
+++ b/generic/tclExecute.c
@@ -14,7 +14,7 @@
  * See the file "license.terms" for information on usage and redistribution of
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclExecute.c,v 1.507 2010/10/16 20:27:39 dkf Exp $
+ * RCS: @(#) $Id: tclExecute.c,v 1.508 2010/10/20 13:34:11 dkf Exp $
  */
 
 #include "tclInt.h"
@@ -3772,6 +3772,29 @@ TEBCresume(
 	CACHE_STACK_INFO();
 	TRACE_APPEND(("ERROR: %.30s\n", O2S(Tcl_GetObjResult(interp))));
 	goto gotError;
+
+	/*
+	 * This is really an unset operation these days. Do not issue.
+	 */
+
+    case INST_DICT_DONE:
+	opnd = TclGetUInt4AtPtr(pc+1);
+	TRACE(("%u\n", opnd));
+	varPtr = LOCAL(opnd);
+	while (TclIsVarLink(varPtr)) {
+	    varPtr = varPtr->value.linkPtr;
+	}
+	if (TclIsVarDirectUnsettable(varPtr) && !TclIsVarInHash(varPtr)) {
+	    if (!TclIsVarUndefined(varPtr)) {
+		TclDecrRefCount(varPtr->value.objPtr);
+	    }
+	    varPtr->value.objPtr = NULL;
+	} else {
+	    DECACHE_STACK_INFO();
+	    TclPtrUnsetVar(interp, varPtr, NULL, NULL, NULL, 0, opnd);
+	    CACHE_STACK_INFO();
+	}
+	NEXT_INST_F(5, 0, 0);
     }
 
     /*
@@ -5972,24 +5995,6 @@ TEBCresume(
 	/* TODO: consider opt like INST_FOREACH_STEP4 */
 	NEXT_INST_F(5, 0, 1);
 
-    case INST_DICT_DONE:
-	opnd = TclGetUInt4AtPtr(pc+1);
-	TRACE(("%u => ", opnd));
-	statePtr = (*LOCAL(opnd)).value.objPtr;
-
-	if (statePtr != NULL && statePtr->typePtr == &dictIteratorType) {
-	    /*
-	     * Set the internal variable to an empty object to signify that we
-	     * don't hold an iterator.
-	     */
-
-	    TclDecrRefCount(statePtr);
-	    TclNewObj(emptyPtr);
-	    (*LOCAL(opnd)).value.objPtr = emptyPtr;
-	    Tcl_IncrRefCount(emptyPtr);
-	}
-	NEXT_INST_F(5, 0, 0);
-
     case INST_DICT_UPDATE_START:
 	opnd = TclGetUInt4AtPtr(pc+1);
 	opnd2 = TclGetUInt4AtPtr(pc+5);