1 files changed, 89 insertions, 0 deletions
diff --git a/IkiWiki/Plugin/conditional.pm b/IkiWiki/Plugin/conditional.pm
new file mode 100644
index 000000000..35418a3ba
--- /dev/null
+++ b/IkiWiki/Plugin/conditional.pm
@@ -0,0 +1,89 @@
+#!/usr/bin/perl
+package IkiWiki::Plugin::conditional;
+
+use warnings;
+use strict;
+use IkiWiki;
+use UNIVERSAL;
+
+# Globals used to pass information into the PageSpec functions.
+our ($sourcepage, $destpage);
+
+sub import { #{{{
+	hook(type => "preprocess", id => "if", call => \&preprocess_if);
+} # }}}
+
+sub preprocess_if (@) { #{{{
+	my %params=@_;
+
+	if (! exists $params{test} || ! exists $params{then}) {
+		return "[[if requires \"test\" and \"then\" parameters]]";
+	}
+
+	my $result=0;
+	$sourcepage=$params{page};
+	$destpage=$params{destpage};
+	# An optimisation to avoid needless looping over every page
+	# and adding of dependencies for simple uses of some of the
+	# tests.
+	if ($params{test} =~ /^(enabled|sourcepage|destpage)\((.*)\)$/) {
+		$result=eval "IkiWiki::PageSpec::match_$1(undef, ".
+			IkiWiki::safequote($2).")";
+	}
+	else {
+		add_depends($params{page}, $params{test});
+
+		foreach my $page (keys %pagesources) {
+			if (pagespec_match($page, $params{test}, $params{page})) {
+				$result=1;
+				last;
+			}
+		}
+	}
+	$sourcepage="";
+	$destpage="";
+
+	my $ret;
+	if ($result) {
+		$ret=$params{then};
+	}
+	elsif (exists $params{else}) {
+		$ret=$params{else};
+	}
+	else {
+		$ret="";
+	}
+	return IkiWiki::preprocess($params{page}, $params{destpage}, $ret);
+} # }}}
+
+package IkiWiki::PageSpec;
+
+sub match_enabled ($$) { #{{{
+	shift;
+	my $plugin=shift;
+	
+	# test if the plugin is enabled
+	return UNIVERSAL::can("IkiWiki::Plugin::".$plugin, "import");
+} #}}}
+
+sub match_sourcepage ($$) { #{{{
+	shift;
+	my $glob=shift;
+	
+	return match_glob($IkiWiki::Plugin::conditional::sourcepage, $glob,
+		$IkiWiki::Plugin::conditional::sourcepage);
+} #}}}
+
+sub match_destpage ($$) { #{{{
+	shift;
+	my $glob=shift;
+	
+	return match_glob($IkiWiki::Plugin::conditional::destpage, $glob,
+		$IkiWiki::Plugin::conditional::sourcepage);
+} #}}}
+
+sub match_included ($$) { #{{{
+	return $IkiWiki::Plugin::conditional::sourcepage ne $IkiWiki::Plugin::conditional::destpage;
+} #}}}
+
+1