use heading identifiers in TOC links

reasoning: if headings have identifiers, they are probably more useful
anchors than the automatically generated anchors we build in the toc
plugin. this can happen if, for example, you use the `multimarkdown`
plugin, which inserts `id` tags for every header it encounters. this
also leverages the `headinganchors` plugin nicely.

keeps backwards-compatibility with old toc-generated #indexXhY
anchors.

diff --git a/IkiWiki/Plugin/toc.pm b/IkiWiki/Plugin/toc.pm
index ac07b9af6b860f0e5a36909197b4d98d0388fa41..4d29e704050f65dd8d22b57f655a1a2b70e19a57 100644 (file)
--- a/IkiWiki/Plugin/toc.pm
+++ b/IkiWiki/Plugin/toc.pm
@@ -59,13 +59,16 @@ sub format (@) {
        my $liststarted=0;
        my $indent=sub { "\t" x $curlevel };
        $p->handler(start => sub {
-               my $tagname=shift;
-               my $text=shift;
+               my ($tagname, $text, $attr) = @_;
                if ($tagname =~ /^h(\d+)$/i) {
                        my $level=$1;
                        my $anchor="index".++$anchors{$level}."h$level";
                        $page.="$text<a name=\"$anchor\"></a>";
-       
+                       # if the heading already has a unique ID, use that instead in TOC
+                       if ($attr->{id}) {
+                               $anchor = $attr->{id};
+                       }
+
                        # Unless we're given startlevel as a parameter,
                        # take the first header level seen as the topmost level,
                        # even if there are higher levels seen later on.
@@ -124,7 +127,7 @@ sub format (@) {
                else {
                        $page.=$text;
                }
-       }, "tagname, text");
+       }, "tagname, text, attr");
        $p->handler(default => sub { $page.=join("", @_) }, "text");
        $p->parse($content);
        $p->eof;