Index: tclCmdMZ.c
===================================================================
RCS file: /cvsroot/tcl/tcl/generic/tclCmdMZ.c,v
retrieving revision 1.39
diff -u -r1.39 tclCmdMZ.c
--- tclCmdMZ.c	2001/06/12 08:07:37	1.39
+++ tclCmdMZ.c	2001/06/13 22:22:08
@@ -2240,6 +2240,11 @@
     return TCL_OK;
 }
 
+#define TCL_SUBST_COMMANDS	0x01
+#define TCL_SUBST_VARIABLES	0x02
+#define TCL_SUBST_BACKSLASHES	0x04
+#define TCL_SUBST_ALL		0x07
+
 /*
  *----------------------------------------------------------------------
  *
@@ -2273,42 +2278,34 @@
     enum substOptions {
 	SUBST_NOBACKSLASHES,      SUBST_NOCOMMANDS,       SUBST_NOVARS
     };
-    Interp *iPtr = (Interp *) interp;
-    Tcl_DString result;
-    char *p, *old, *value;
-    int optionIndex, code, count, doVars, doCmds, doBackslashes, i;
+    Tcl_Obj *result;
+    int optionIndex, i, flags = TCL_SUBST_ALL;
 
     /*
      * Parse command-line options.
      */
 
-    doVars = doCmds = doBackslashes = 1;
     for (i = 1; i < (objc-1); i++) {
 	p = Tcl_GetString(objv[i]);
 	if (*p != '-') {
 	    break;
 	}
 	if (Tcl_GetIndexFromObj(interp, objv[i], substOptions,
-		"switch", 0, &optionIndex) != TCL_OK) {
-
+				"switch", 0, &optionIndex) != TCL_OK) {
 	    return TCL_ERROR;
 	}
 	switch (optionIndex) {
-	    case SUBST_NOBACKSLASHES: {
-		doBackslashes = 0;
-		break;
-	    }
-	    case SUBST_NOCOMMANDS: {
-		doCmds = 0;
-		break;
-	    }
-	    case SUBST_NOVARS: {
-		doVars = 0;
-		break;
-	    }
-	    default: {
-		panic("Tcl_SubstObjCmd: bad option index to SubstOptions");
-	    }
+	case SUBST_NOBACKSLASHES:
+	    flags &= ~TCL_SUBST_BACKSLASHES;
+	    break;
+	case SUBST_NOCOMMANDS:
+	    flags &= ~TCL_SUBST_COMMANDS;
+	    break;
+	case SUBST_NOVARS:
+	    flags &= ~TCL_SUBST_VARIABLES;
+	    break;
+	default:
+	    panic("Tcl_SubstObjCmd: bad option index to SubstOptions");
 	}
     }
     if (i != (objc-1)) {
@@ -2317,24 +2314,60 @@
 	return TCL_ERROR;
     }
 
-    /*
-     * Scan through the string one character at a time, performing
-     * command, variable, and backslash substitutions.
-     */
+    result = Tcl_SubstObj(interp, objv[i], flags);
+    if (result == NULL) {
+	return TCL_ERROR;
+    }
+    Tcl_SetObjResult(interp, result);
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_SubstObj --
+ *
+ *	This function implements the main functionality of the "subst"
+ *	Tcl command.  It scans through the supplied string one
+ *	character at a time, performing command, variable and backslash
+ *	substitutions as it goes. This command is largely based on an
+ *	implementation by Andrew Payne.
+ *
+ * Results:
+ *	A Tcl_Obj* which contains the substituted string, or a NULL to
+ *	indicate an error occurred (when a message will be left in the
+ *	interpreter's result.)  The reference count of the object
+ *	returned will be zero.
+ *
+ * Side effects:
+ *	See the user documentation.
+ *
+ *----------------------------------------------------------------------
+ */
+
+Tcl_Obj *
+Tcl_SubstObj(interp, objPtr, flags)
+    Tcl_Interp *interp;			/* Current interpreter. */
+    Tcl_Obj *objPtr;			/* String to substitute. */
+    int flags;				/* What substitutions to apply. */
+{
+    Interp *iPtr = (Interp *) interp;
+    Tcl_Obj *result = Tcl_NewObj();
+    char *old, *p;
 
-    Tcl_DStringInit(&result);
-    old = p = Tcl_GetString(objv[i]);
+    old = p = Tcl_GetString(objPtr);
     while (*p != 0) {
 	switch (*p) {
 	    case '\\':
-		if (doBackslashes) {
+		if (flags & TCL_SUBST_BACKSLASHES) {
 		    char buf[TCL_UTF_MAX];
+		    int count;
 
 		    if (p != old) {
-			Tcl_DStringAppend(&result, old, p-old);
+			Tcl_AppendToObj(result, old, p-old);
 		    }
-		    Tcl_DStringAppend(&result, buf,
-			    Tcl_UtfBackslash(p, &count, buf));
+		    Tcl_AppendToObj(result, buf,
+				    Tcl_UtfBackslash(p, &count, buf));
 		    p += count;
 		    old = p;
 		} else {
@@ -2343,16 +2376,17 @@
 		break;
 
 	    case '$':
-		if (doVars) {
+		if (flags & TCL_SUBST_VARIABLES) {
+		    char *value;
+
 		    if (p != old) {
-			Tcl_DStringAppend(&result, old, p-old);
+			Tcl_AppendToObj(result, old, p-old);
 		    }
 		    value = Tcl_ParseVar(interp, p, &p);
 		    if (value == NULL) {
-			Tcl_DStringFree(&result);
-			return TCL_ERROR;
+			goto errorExit;
 		    }
-		    Tcl_DStringAppend(&result, value, -1);
+		    Tcl_AppendToObj(result, value, -1);
 		    old = p;
 		} else {
 		    p++;
@@ -2360,19 +2394,26 @@
 		break;
 
 	    case '[':
-		if (doCmds) {
+		if (flags & TCL_SUBST_COMMANDS) {
+		    int code;
+
 		    if (p != old) {
-			Tcl_DStringAppend(&result, old, p-old);
+			Tcl_AppendToObj(result, old, p-old);
 		    }
 		    iPtr->evalFlags = TCL_BRACKET_TERM;
 		    code = Tcl_Eval(interp, p+1);
 		    if (code == TCL_ERROR) {
-			Tcl_DStringFree(&result);
-			return code;
+			goto errorExit;
 		    }
 		    old = p = (p+1 + iPtr->termOffset+1);
-		    Tcl_DStringAppend(&result, iPtr->result, -1);
+		    Tcl_AppendObjToObj(result, Tcl_GetObjResult(interp));
 		    Tcl_ResetResult(interp);
+		    /*
+		     * NOTE: NEW BEHAVIOUR! DOCUMENT...
+		     */
+		    if (code == TCL_BREAK) {
+			return result;
+		    }
 		} else {
 		    p++;
 		}
@@ -2383,11 +2424,16 @@
 		break;
 	}
     }
+
     if (p != old) {
-	Tcl_DStringAppend(&result, old, p-old);
+	Tcl_AppendToObj(result, old, p-old);
     }
-    Tcl_DStringResult(interp, &result);
-    return TCL_OK;
+
+    return result;
+
+  errorExit:
+    Tcl_DecrRefCount(result);
+    return NULL;
 }
 
 /*