Index: generic/tclCmdIL.c
===================================================================
RCS file: /cvsroot/tcl/tcl/generic/tclCmdIL.c,v
retrieving revision 1.78
diff -u -r1.78 tclCmdIL.c
--- generic/tclCmdIL.c	17 Jul 2005 21:17:30 -0000	1.78
+++ generic/tclCmdIL.c	18 Jul 2005 17:43:18 -0000
@@ -3305,7 +3305,7 @@
 	    dataType = INTEGER;
 	    break;
 	case LSEARCH_NOCASE:		/* -nocase */
-	    strCmpFn = strcasecmp;
+	    strCmpFn = TclUtfCasecmp;
 	    noCase = 1;
 	    break;
 	case LSEARCH_NOT:		/* -not */
@@ -3661,7 +3661,7 @@
 			 */
 
 			if (noCase) {
-			    match = (strcasecmp(bytes, patternBytes) == 0);
+			    match = (TclUtfCasecmp(bytes, patternBytes) == 0);
 			} else {
 			    match = (memcmp(bytes, patternBytes,
 				    (size_t) length) == 0);
@@ -3883,6 +3883,7 @@
     Tcl_SetObjResult(interp, listPtr);
     return TCL_OK;
 }
+
 
 /*
  *----------------------------------------------------------------------
@@ -4040,7 +4041,7 @@
 	    sortInfo.sortMode = SORTMODE_INTEGER;
 	    break;
 	case LSORT_NOCASE:
-	    sortInfo.strCmpFn = strcasecmp;
+	    sortInfo.strCmpFn = TclUtfCasecmp;
 	    break;
 	case LSORT_REAL:
 	    sortInfo.sortMode = SORTMODE_REAL;
Index: generic/tclCmdMZ.c
===================================================================
RCS file: /cvsroot/tcl/tcl/generic/tclCmdMZ.c,v
retrieving revision 1.127
diff -u -r1.127 tclCmdMZ.c
--- generic/tclCmdMZ.c	17 Jul 2005 21:17:37 -0000	1.127
+++ generic/tclCmdMZ.c	18 Jul 2005 17:43:18 -0000
@@ -2633,7 +2633,7 @@
 	    matchVarObj = objv[i];
 	    numMatchesSaved = -1;
 	} else if (index == OPT_NOCASE) {
-	    strCmpFn = strcasecmp;
+	    strCmpFn = TclUtfCasecmp;
 	    noCase = 1;
 	} else {
 	    if (foundmode) {
Index: generic/tclInt.decls
===================================================================
RCS file: /cvsroot/tcl/tcl/generic/tclInt.decls,v
retrieving revision 1.90
diff -u -r1.90 tclInt.decls
--- generic/tclInt.decls	5 Jul 2005 18:15:55 -0000	1.90
+++ generic/tclInt.decls	18 Jul 2005 17:43:18 -0000
@@ -897,6 +897,10 @@
     TclPlatformType *TclGetPlatform(void)
 }
 
+declare 225 generic {
+    int TclUtfCasecmp( CONST char *cs, CONST char *ct )
+}
+
 ##############################################################################
 
 # Define the platform specific internal Tcl interface. These functions are
Index: generic/tclUtf.c
===================================================================
RCS file: /cvsroot/tcl/tcl/generic/tclUtf.c,v
retrieving revision 1.34
diff -u -r1.34 tclUtf.c
--- generic/tclUtf.c	10 May 2005 18:34:51 -0000	1.34
+++ generic/tclUtf.c	18 Jul 2005 17:43:18 -0000
@@ -1042,15 +1042,27 @@
      * representation of \u0001 (the byte 0x01.)
      */
     while (numChars-- > 0) {
+	unsigned char s, t;
 	/*
 	 * n must be interpreted as chars, not bytes.
 	 * This should be called only when both strings are of
 	 * at least n chars long (no need for \0 check)
 	 */
-	cs += TclUtfToUniChar(cs, &ch1);
-	ct += TclUtfToUniChar(ct, &ch2);
-	if (ch1 != ch2) {
-	    return (ch1 - ch2);
+	s = *cs;
+	t = *ct;
+	if ((s | t) < 0x80) {
+	    /* We have 7bit ASCII characters in both strings */
+	    if (s != t) {
+		return (s - t);
+	    }
+	    cs++;
+	    ct++;
+	} else {
+	    cs += TclUtfToUniChar(cs, &ch1);
+	    ct += TclUtfToUniChar(ct, &ch2);
+	    if (ch1 != ch2) {
+		return (ch1 - ch2);
+	    }
 	}
     }
     return 0;
@@ -1080,20 +1092,40 @@
     CONST char *ct;		/* UTF string cs is compared to. */
     unsigned long numChars;	/* Number of UTF chars to compare. */
 {
-    Tcl_UniChar ch1, ch2;
     while (numChars-- > 0) {
+	unsigned char s, t;
 	/*
 	 * n must be interpreted as chars, not bytes.
 	 * This should be called only when both strings are of
 	 * at least n chars long (no need for \0 check)
 	 */
-	cs += TclUtfToUniChar(cs, &ch1);
-	ct += TclUtfToUniChar(ct, &ch2);
-	if (ch1 != ch2) {
-	    ch1 = Tcl_UniCharToLower(ch1);
-	    ch2 = Tcl_UniCharToLower(ch2);
+	s = *cs;
+	t = *ct;
+	if ((s | t) < 0x80) {
+	    /* We have 7bit ASCII characters in both strings */
+	    if (s != t) {
+		if (s >= 'A' && s <= 'Z') {
+		    s |= 0x20;
+		}
+		if (t >= 'A' && t <= 'Z') {
+		    t |= 0x20;
+		}
+		if (s != t) {
+		    return (s - t);
+		}
+	    }
+	    cs++;
+	    ct++;
+	} else {
+	    Tcl_UniChar ch1, ch2;
+	    cs += TclUtfToUniChar(cs, &ch1);
+	    ct += TclUtfToUniChar(ct, &ch2);
 	    if (ch1 != ch2) {
-		return (ch1 - ch2);
+		ch1 = Tcl_UniCharToLower(ch1);
+		ch2 = Tcl_UniCharToLower(ch2);
+		if (ch1 != ch2) {
+		    return (ch1 - ch2);
+		}
 	    }
 	}
     }
@@ -1103,6 +1135,67 @@
 /*
  *----------------------------------------------------------------------
  *
+ * TclUtfCasecmp --
+ *
+ *	Compare string cs to string ct case insensitively.
+ *
+ * Results:
+ *	Return <0 if cs < ct, 0 if cs == ct, or >0 if cs > ct.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+TclUtfCasecmp(cs, ct)
+    CONST char *cs;		/* UTF string to compare to ct. */
+    CONST char *ct;		/* UTF string cs is compared to. */
+{
+    unsigned char s, t;
+    do {
+	s = *cs;
+	t = *ct;
+	if ((s | t) < 0x80) {
+	    /* We have 7bit ASCII characters in both strings */
+	    if (s != t) {
+		if (s >= 'A' && s <= 'Z') {
+		    s |= 0x20;
+		}
+		if (t >= 'A' && t <= 'Z') {
+		    t |= 0x20;
+		}
+		if (s != t) {
+		    return (s - t);
+		}
+	    }
+	    cs++; ct++;
+	} else {
+	    Tcl_UniChar ch1, ch2;
+	    cs += TclUtfToUniChar(cs, &ch1);
+	    ct += TclUtfToUniChar(ct, &ch2);
+	    if (ch1 != ch2) {
+		ch1 = Tcl_UniCharToLower(ch1);
+		ch2 = Tcl_UniCharToLower(ch2);
+		if (ch1 != ch2) {
+		    return (ch1 - ch2);
+		}
+	    }
+	}
+    } while (s != '\0');
+    /* 
+     * At this point we can be sure that both strings have reached the
+     * end, because otherwise one of the returns above would alread
+     * have fired, that's also the reason why only one of the strings
+     * needs to be checked for a null character the while condition.
+     */
+    return 0; 
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
  * Tcl_UniCharToUpper --
  *
  *	Compute the uppercase equivalent of the given Unicode character.
Index: tests/cmdIL.test
===================================================================
RCS file: /cvsroot/tcl/tcl/tests/cmdIL.test,v
retrieving revision 1.26
diff -u -r1.26 cmdIL.test
--- tests/cmdIL.test	1 Jun 2005 11:00:35 -0000	1.26
+++ tests/cmdIL.test	18 Jul 2005 17:43:18 -0000
@@ -431,6 +431,12 @@
 } -result 0 -cleanup {
     rename test_lsort ""
 }
+test cmdIL-5.6 {lsort -nocase with non-ASCII characters} -body {
+    lsort -nocase {\u00c4a \u20aca \u00c4c \u00e4b Ac ab Aa}
+} -result "Aa ab Ac \u00c4a \u00e4b \u00c4c \u20aca"
+test cmdIL-5.7 {lsort -nocase with ASCII non-letter characters} {
+    list [lsort -nocase {@ `}] [lsort -nocase {` @}]
+} {{@ `} {@ `}}
 
 # Compiled version
 test cmdIL-6.1 {lassign command syntax} -body {
