* Add toc (table of contents) plugin.

[www/ikiwiki.git] / IkiWiki / Plugin / toc.pm

diff --git a/IkiWiki/Plugin/toc.pm b/IkiWiki/Plugin/toc.pm
new file mode 100644 (file)
index 0000000..c36ce28
--- /dev/null
+++ b/IkiWiki/Plugin/toc.pm
@@ -0,0 +1,116 @@
+#!/usr/bin/perl
+# Table Of Contents generator
+package IkiWiki::Plugin::toc;
+
+use warnings;
+use strict;
+use IkiWiki;
+use HTML::Parser;
+
+sub import { #{{{
+       IkiWiki::hook(type => "preprocess", id => "toc",
+               call => \&preprocess);
+       IkiWiki::hook(type => "format", id => "toc",
+               call => \&format);
+} # }}}
+
+my @tocs;
+
+sub preprocess (@) { #{{{
+       my %params=@_;
+
+       $params{levels}=1 unless exists $params{levels};
+
+       # It's too early to generate the toc here, so just record the
+       # info.
+       push @tocs, \%params;
+
+       return "\n[[toc $#tocs]]\n";
+} # }}}
+
+sub format ($) { #{{{
+       my $content=shift;
+       
+       return $content unless @tocs && $content=~/\[\[toc (\d+)\]\]/ && $#tocs >= $1;
+       my $id=$1;
+       my %params=%{$tocs[$id]};
+
+       my $p=HTML::Parser->new(api_version => 3);
+       my $page="";
+       my $index="";
+       my %anchors;
+       my $curlevel;
+       my $startlevel=0;
+       my $liststarted=0;
+       my $indent=sub { "\t" x $curlevel };
+       $p->handler(start => sub {
+               my $tagname=shift;
+               my $text=shift;
+               if ($tagname =~ /^h(\d+)$/i) {
+                       my $level=$1;
+                       my $anchor="index".++$anchors{$level}."h$level";
+                       $page.="$text<a name=\"$anchor\" />";
+       
+                       # Take the first header level seen as the topmost level,
+                       # even if there are higher levels seen later on.
+                       if (! $startlevel) {
+                               $startlevel=$level;
+                               $curlevel=$startlevel-1;
+                       }
+                       elsif ($level < $startlevel) {
+                               $level=$startlevel;
+                       }
+                       
+                       return if $level - $startlevel >= $params{levels};
+       
+                       if ($level > $curlevel) {
+                               while ($level > $curlevel + 1) {
+                                       $index.=&$indent."<ol>\n";
+                                       $curlevel++;
+                                       $index.=&$indent."<li class=\"L$curlevel\">\n";
+                               }
+                               $index.=&$indent."<ol>\n";
+                               $curlevel=$level;
+                               $liststarted=1;
+                       }
+                       elsif ($level < $curlevel) {
+                               while ($level < $curlevel) {
+                                       $index.=&$indent."</li>\n" if $curlevel;
+                                       $curlevel--;
+                                       $index.=&$indent."</ol>\n";
+                               }
+                               $liststarted=0;
+                       }
+       
+                       $p->handler(text => sub {
+                               $page.=join("", @_);
+                               $index.=&$indent."</li>\n" unless $liststarted;
+                               $liststarted=0;
+                               $index.=&$indent."<li class=\"L$curlevel\">".
+                                       "<a href=\"#$anchor\">".
+                                       join("", @_).
+                                       "</a>\n";
+                               $p->handler(text => undef);
+                       }, "dtext");
+               }
+               else {
+                       $page.=$text;
+               }
+       }, "tagname, text");
+       $p->handler(default => sub { $page.=join("", @_) }, "text");
+       $p->parse($content);
+       $p->eof;
+
+       while ($startlevel && $curlevel >= $startlevel) {
+               $index.=&$indent."</li>\n" if $curlevel;
+               $curlevel--;
+               $index.=&$indent."</ol>\n";
+       }
+
+       # Ignore cruft around the toc marker, probably <p> tags added by
+       # markdown which shouldn't appear in a list anyway.
+       $page=~s/\n.*\[\[toc $id\]\].*\n/$index/;
+       return $page;
+}
+
+1