doc/todo/Add_a_plugin_to_list_available_pre-processor_commands.mdwn



I've found myself wanting to know which [[plugins]] are switched on so I know which pre-processor commands I can use.  The attached [[patch]] adds a new plugin that generates the list of available plugins. -- [[Will]]

Good idea, I do see a few problems:

preprocessor directives do not necessarily have the same name as the
plugin that contains them (for example, the graphviz plugin adds a graph
directive). Won't keys %{IkiWiki::hooks{preprocess}} work?
"listplugins" is a bit misnamed since it only does preprocessor directives.
comment was copied from version plugin and still mentions version :-)
Seems like [[ikiwiki/formatting]] could benefit from including the
list.. however, just a list of preprocessor directive names is not
the most user-friendly thing that could be put on that page. It would
be nice if there were also a short description and maybe an example of
use. Seems like the place to include that info would be in the call
to hook().
(Maybe adding that is more involved than you want to go though..)

--[[Joey]]

#!/usr/bin/perl
# Ikiwiki listplugins plugin.
package IkiWiki::Plugin::listplugins;

use warnings;
use strict;
use IkiWiki 2.00;

sub import { #{{{
	hook(type => "getsetup", id => "listplugins", call => \&getsetup);
	hook(type => "needsbuild", id => "listplugins", call => \&needsbuild);
	hook(type => "preprocess", id => "listplugins", call => \&preprocess);
} # }}}

sub getsetup () { #{{{
	return
		plugin => {
			safe => 1,
			rebuild => undef,
		},
} #}}}

my @pluginlist;
my $pluginString;

sub needsbuild (@) { #{{{
	my $needsbuild=shift;

	my @rawpluginlist = sort(IkiWiki::listplugins());
	@pluginlist = ();
	
	foreach my $plugin (@rawpluginlist) {
		if ( exists $IkiWiki::hooks{preprocess}{$plugin} ) {
			push(@pluginlist,$plugin);
		}
	}

	$pluginString = join (' ', @pluginlist);

	foreach my $page (keys %pagestate) {
		if (exists $pagestate{$page}{listplugins}{shown}) {
			if ($pagestate{$page}{listplugins}{shown} ne $pluginString) {
				push @$needsbuild, $pagesources{$page};
			}
			if (exists $pagesources{$page} &&
			    grep { $_ eq $pagesources{$page} } @$needsbuild) {
				# remove state, will be re-added if
				# the version is still shown during the
				# rebuild
				delete $pagestate{$page}{listplugins}{shown};
			}
		}
	}
} # }}}

sub preprocess (@) { #{{{
	my %params=@_;
	
	$pagestate{$params{destpage}}{listplugins}{shown}=$pluginString;
	
	my $result = "<ul class=\"pluginlist\">";
	my $thisPlugin;
	foreach $thisPlugin (@pluginlist) {
		$result .= "<li class=\"pluginlist\">$thisPlugin</li>";
	}
	$result .= "</ul>";
	
	return $result;
} # }}}

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