1 files changed, 43 insertions, 4 deletions
diff --git a/generic/tclParse.c b/generic/tclParse.c
index 90ec43d..025304c 100644
--- a/generic/tclParse.c
+++ b/generic/tclParse.c
@@ -628,6 +628,47 @@ TclIsSpaceProc(
 /*
  *----------------------------------------------------------------------
  *
+ * TclIsBareword--
+ *
+ *	Report whether byte is one that can be part of a "bareword".
+ *	This concept is named in expression parsing, where it determines
+ *	what can be a legal function name, but is the same definition used
+ *	in determining what variable names can be parsed as variable
+ *	substitutions without the benefit of enclosing braces.  The set of
+ *	ASCII chars that are accepted are the numeric chars ('0'-'9'),
+ *	the alphabetic chars ('a'-'z', 'A'-'Z')	and underscore ('_').
+ *
+ * Results:
+ *	Returns 1, if byte is in the accepted set of chars, 0 otherwise.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+TclIsBareword(
+    char byte)
+{
+    if (byte < '0' || byte > 'z') {
+	return 0;
+    }
+    if (byte <= '9' || byte >= 'a') {
+	return 1;
+    }
+    if (byte == '_') {
+	return 1;
+    }
+    if (byte < 'A' || byte > 'Z') {
+	return 0;
+    }
+    return 1;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
  * ParseWhiteSpace --
  *
  *	Scans up to numBytes bytes starting at src, consuming white space
@@ -1343,7 +1384,6 @@ Tcl_ParseVarName(
 {
     Tcl_Token *tokenPtr;
     register const char *src;
-    unsigned char c;
     int varIndex;
     unsigned array;
 
@@ -1427,13 +1467,12 @@ Tcl_ParseVarName(
 	tokenPtr->numComponents = 0;
 
 	while (numBytes) {
-	    c = UCHAR(*src);
-	    if (isalnum(c) || (c == '_')) {	/* INTL: ISO only, UCHAR. */
+	    if (TclIsBareword(*src)) {
 		src += 1;
 		numBytes -= 1;
 		continue;
 	    }
-	    if ((c == ':') && (numBytes != 1) && (src[1] == ':')) {
+	    if ((src[0] == ':') && (numBytes != 1) && (src[1] == ':')) {
 		src += 2;
 		numBytes -= 2;
 		while (numBytes && (*src == ':')) {