1 files changed, 116 insertions, 0 deletions
diff --git a/IkiWiki/Plugin/toc.pm b/IkiWiki/Plugin/toc.pm
new file mode 100644
index 000000000..c36ce2893
--- /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