--- origineel	2004-11-01 16:56:39.000000000 +0100
+++ TWiki.pm	2004-11-01 18:23:05.000000000 +0100
@@ -1,4 +1,5 @@
 # Main Module of TWiki Collaboration Platform, http://TWiki.org/
+# $Id: TWiki.pm,v 1.3 2004/11/01 17:23:00 rdgon Exp $
 # ($wikiversion has version info)
 #
 # Copyright (C) 1999-2003 Peter Thoeny, peter@thoeny.com
@@ -1604,6 +1605,7 @@
     my $tabs = "";
     my $anchor = "";
     my $highest = 99;
+	my %toc_anchors;
     foreach $line ( @list ) {
         if( $line =~ /^.*<pre>.*$/io ) {
             $insidePre = 1;
@@ -1630,7 +1632,8 @@
                 $line  =~ s/$headerPatternHt/$2/gio;
             }
             if( ( $line ) && ( $level <= $depth ) ) {
-                $anchor = makeAnchorName( $line );
+                $anchor = makeAnchorName( $line, \%toc_anchors );
+		
                 # cut TOC exclude '---+ heading !! exclude'
                 $line  =~ s/\s*$headerPatternNoTOC.+$//go;
                 next unless $line;
@@ -2275,9 +2278,12 @@
 
 # =========================
 # Build an HTML <Hn> element with suitable anchor for linking from %TOC%
+# parameters
+#	third: theHash: hash with names of already created anchors for
+#					making unique anchor names
 sub makeAnchorHeading
 {
-    my( $theText, $theLevel ) = @_;
+    my( $theText, $theLevel, $theHash ) = @_;
 
     # - Need to build '<nop><h1><a name="atext"> text </a></h1>'
     #   type markup.
@@ -2287,7 +2293,7 @@
     # - filter out $headerPatternNoTOC ( '!!' and '%NOTOC%' )
 
     my $text = $theText;
-    my $anchorName = &makeAnchorName( $text );
+    my $anchorName = &makeAnchorName( $text, $theHash );
     $text =~ s/$headerPatternNoTOC//o; # filter '!!', '%NOTOC%'
     my $hasAnchor = 0;  # text contains potential anchor
     $hasAnchor = 1 if( $text =~ m/<a /i );
@@ -2309,9 +2315,11 @@
 
 # =========================
 # Build a valid HTML anchor name
+#    if hash $known_anchors defined: use hash to generate unique anchor
+#    name.
 sub makeAnchorName
 {
-    my( $anchorName ) = @_;
+    my( $anchorName, $known_anchors ) = @_;
 
     $anchorName =~ s/^[\s\#\_]*//;          # no leading space nor '#', '_'
     $anchorName =~ s/[\s\_]*$//;            # no trailing space, nor '_'
@@ -2331,6 +2339,19 @@
     $anchorName =~ s/([\x7f-\xff])/_/g;		# Map 8-bit chars
     ##$anchorName =~ handleUrlEncode( $anchorName );	# Was doing URL-encode 
 
+	if (defined ($known_anchors))
+	{	# toc-anchor must be unique. Use hash to make anchor unique
+		my $proposed_anchor = $anchorName;
+		my $sn = 1;
+		while (defined ($known_anchors->{$proposed_anchor}))
+		{	# anchor already exists; try one with the next serial number
+			$proposed_anchor = "${anchorName}_$sn";
+			$sn++;
+		}
+		$anchorName = $proposed_anchor;
+		$known_anchors->{$anchorName} = 1;
+	}
+
     return $anchorName;
 }
 
@@ -2536,6 +2557,7 @@
     # Wiki Plugin Hook
     &TWiki::Plugins::startRenderingHandler( $text, $theWeb, $meta );
 
+	my %html_anchors;
     foreach( split( /\n/, $text ) ) {
 
         # change state:
@@ -2599,11 +2621,11 @@
 
 # Headings
             # '<h6>...</h6>' HTML rule
-            s/$headerPatternHt/&makeAnchorHeading($2,$1)/geoi;
+            s/$headerPatternHt/&makeAnchorHeading($2,$1,\%html_anchors )/geoi;
             # '\t+++++++' rule
-            s/$headerPatternSp/&makeAnchorHeading($2,(length($1)))/geo;
+            s/$headerPatternSp/&makeAnchorHeading($2,(length($1)),\%html_anchors )/geo;
             # '----+++++++' rule
-            s/$headerPatternDa/&makeAnchorHeading($2,(length($1)))/geo;
+            s/$headerPatternDa/&makeAnchorHeading($2,(length($1)),\%html_anchors )/geo;
 
 # Horizontal rule
             s/^---+/<hr \/>/;