allow format to use any language supported by highlight

format: Provide a htmlizefallback hook that other plugins can use to
handle formats that are not suitable for general-purpose htmlize hooks.

highlight: Use the hook to allow formatting of any language/extension,
without it needing to be enabled for standalone source files.

highlight: If the highlight perl binding is not available, fallback
safely to a passthrough mode.

2 files changed, 40 insertions, 9 deletions

diff --git a/IkiWiki/Plugin/format.pm b/IkiWiki/Plugin/format.pm
index bbe3aa9fe..1513cbed7 100644
--- a/IkiWiki/Plugin/format.pm
+++ b/IkiWiki/Plugin/format.pm
@@ -10,21 +10,33 @@ sub import {
 }
 
 sub preprocess (@) {
-	my $format=$_[0];
-	shift; shift;
-	my $text=$_[0];
-	shift; shift;
 	my %params=@_;
+	my $format=shift;
+	shift;
+	my $text=IkiWiki::preprocess($params{page}, $params{destpage}, shift);
+	shift;
 
 	if (! defined $format || ! defined $text) {
 		error(gettext("must specify format and text"));
 	}
-	elsif (! exists $IkiWiki::hooks{htmlize}{$format}) {
-		error(sprintf(gettext("unsupported page format %s"), $format));
+	elsif (exists $IkiWiki::hooks{htmlize}{$format}) {
+		return IkiWiki::htmlize($params{page}, $params{destpage},
+		                        $format, $text);
 	}
+	else {
+		# Other plugins can register htmlizefallback
+		# hooks to add support for page types
+		# not suitable for htmlize. Try them until
+		# one succeeds.
+		my $ret;
+		IkiWiki::run_hooks(htmlizefallback => sub {
+			$ret=shift->($format, $text)
+				unless defined $ret;
+		});
+		return $ret if defined $ret;
 
-	return IkiWiki::htmlize($params{page}, $params{destpage}, $format,
-		IkiWiki::preprocess($params{page}, $params{destpage}, $text));
+		error(sprintf(gettext("unsupported page format %s"), $format));
+	}
 }
 
 1
diff --git a/IkiWiki/Plugin/highlight.pm b/IkiWiki/Plugin/highlight.pm
index 117ab5898..f116c41dd 100644
--- a/IkiWiki/Plugin/highlight.pm
+++ b/IkiWiki/Plugin/highlight.pm
@@ -4,7 +4,6 @@ package IkiWiki::Plugin::highlight;
 use warnings;
 use strict;
 use IkiWiki 3.00;
-use highlight;
 
 # locations of highlight's files
 my $filetypes="/etc/highlight/filetypes.conf";
@@ -13,6 +12,9 @@ my $langdefdir="/usr/share/highlight/langDefs";
 sub import {
 	hook(type => "getsetup", id => "highlight",  call => \&getsetup);
 	hook(type => "checkconfig", id => "highlight", call => \&checkconfig);
+	# this hook is used by the format plugin
+	hook(type => "htmlizefallback", id => "highlight", call =>
+		\&htmlizefallback);
 }
 
 sub getsetup () {
@@ -59,6 +61,17 @@ sub checkconfig () {
 	}
 }
 
+sub htmlizefallback {
+	my $format=lc shift;
+	my $langfile=ext2langfile($format);
+
+	if (! defined $langfile) {
+		return;
+	}
+
+	return highlight($langfile, shift);
+}
+
 my %ext2lang;
 my $filetypes_read=0;
 
@@ -103,6 +116,12 @@ sub highlight ($$) {
 	my $langfile=shift;
 	my $input=shift;
 
+	eval q{use highlight};
+	if ($@) {
+		print STDERR gettext("warning: highlight perl module not available; falling back to pass through");
+		return $input;
+	}
+
 	my $gen = highlightc::CodeGenerator_getInstance($highlightc::XHTML);
 	$gen->setFragmentCode(1); # generate html fragment
 	$gen->setHTMLEnclosePreTag(1); # include stylish <pre>