From: Joey Hess <joey@kitenet.net>
Date: Sun, 18 Mar 2012 18:22:28 +0000 (-0400)
Subject: changelog
X-Git-Url: https://sipb.mit.edu/gitweb.cgi/ikiwiki.git/commitdiff_plain/a812692a50de69215a8267c7b0b1d7bf62bdfa32?hp=9c8262c6637773891871c24862874fcdbef9c651

changelog
---

diff --git a/IkiWiki/Plugin/inline.pm b/IkiWiki/Plugin/inline.pm
index bdab5793b..687c8a48f 100644
--- a/IkiWiki/Plugin/inline.pm
+++ b/IkiWiki/Plugin/inline.pm
@@ -19,7 +19,7 @@ sub import {
 	hook(type => "checkconfig", id => "inline", call => \&checkconfig);
 	hook(type => "sessioncgi", id => "inline", call => \&sessioncgi);
 	hook(type => "preprocess", id => "inline", 
-		call => \&IkiWiki::preprocess_inline);
+		call => \&IkiWiki::preprocess_inline, scan => 1);
 	hook(type => "pagetemplate", id => "inline",
 		call => \&IkiWiki::pagetemplate_inline);
 	hook(type => "format", id => "inline", call => \&format, first => 1);
@@ -155,6 +155,23 @@ sub preprocess_inline (@) {
 	if (! exists $params{pages} && ! exists $params{pagenames}) {
 		error gettext("missing pages parameter");
 	}
+
+	if (! defined wantarray) {
+		# Running in scan mode: only do the essentials
+
+		if (yesno($params{trail}) && IkiWiki::Plugin::trail->can("preprocess_trailitems")) {
+			# default to sorting age, the same as inline itself,
+			# but let the params override that
+			IkiWiki::Plugin::trail::preprocess_trailitems(sort => 'age', %params);
+		}
+
+		return;
+	}
+
+	if (yesno($params{trail}) && IkiWiki::Plugin::trail->can("preprocess_trailitems")) {
+		scalar IkiWiki::Plugin::trail::preprocess_trailitems(sort => 'age', %params);
+	}
+
 	my $raw=yesno($params{raw});
 	my $archive=yesno($params{archive});
 	my $rss=(($config{rss} || $config{allowrss}) && exists $params{rss}) ? yesno($params{rss}) : $config{rss};
diff --git a/IkiWiki/Plugin/trail.pm b/IkiWiki/Plugin/trail.pm
new file mode 100644
index 000000000..29830175e
--- /dev/null
+++ b/IkiWiki/Plugin/trail.pm
@@ -0,0 +1,445 @@
+#!/usr/bin/perl
+# Copyright © 2008-2011 Joey Hess
+# Copyright © 2009-2012 Simon McVittie <http://smcv.pseudorandom.co.uk/>
+# Licensed under the GNU GPL, version 2, or any later version published by the
+# Free Software Foundation
+package IkiWiki::Plugin::trail;
+
+use warnings;
+use strict;
+use IkiWiki 3.00;
+
+sub import {
+	hook(type => "getsetup", id => "trail", call => \&getsetup);
+	hook(type => "needsbuild", id => "trail", call => \&needsbuild);
+	hook(type => "preprocess", id => "trailoptions", call => \&preprocess_trailoptions, scan => 1);
+	hook(type => "preprocess", id => "trailitem", call => \&preprocess_trailitem, scan => 1);
+	hook(type => "preprocess", id => "trailitems", call => \&preprocess_trailitems, scan => 1);
+	hook(type => "preprocess", id => "traillink", call => \&preprocess_traillink, scan => 1);
+	hook(type => "pagetemplate", id => "trail", call => \&pagetemplate);
+	hook(type => "build_affected", id => "trail", call => \&build_affected);
+}
+
+=head1 Page state
+
+If a page C<$T> is a trail, then it can have
+
+=over
+
+=item * C<$pagestate{$T}{trail}{contents}>
+
+Reference to an array of lists each containing either:
+
+=over
+
+=item * C<[link, "link"]>
+
+A link specification, pointing to the same page that C<[[link]]> would select
+
+=item * C<[pagespec, "posts/*", "age", 0]>
+
+A match by pagespec; the third array element is the sort order and the fourth
+is whether to reverse sorting
+
+=back
+
+=item * C<$pagestate{$T}{trail}{sort}>
+
+A [[ikiwiki/pagespec/sorting]] order; if absent or undef, the trail is in
+the order given by the links that form it
+
+=item * C<$pagestate{$T}{trail}{circular}>
+
+True if this trail is circular (i.e. going "next" from the last item is
+allowed, and takes you back to the first)
+
+=item * C<$pagestate{$T}{trail}{reverse}>
+
+True if C<sort> is to be reversed.
+
+=back
+
+If a page C<$M> is a member of a trail C<$T>, then it has
+
+=over
+
+=item * C<$pagestate{$M}{trail}{item}{$T}[0]>
+
+The page before this one in C<$T> at the last rebuild, or undef.
+
+=item * C<$pagestate{$M}{trail}{item}{$T}[1]>
+
+The page after this one in C<$T> at the last refresh, or undef.
+
+=back
+
+=cut
+
+sub getsetup () {
+	return
+		plugin => {
+			safe => 1,
+			rebuild => undef,
+		},
+}
+
+sub needsbuild (@) {
+	my $needsbuild=shift;
+	foreach my $page (keys %pagestate) {
+		if (exists $pagestate{$page}{trail}) {
+			if (exists $pagesources{$page} &&
+			    grep { $_ eq $pagesources{$page} } @$needsbuild) {
+				# Remove state, it will be re-added
+				# if the preprocessor directive is still
+				# there during the rebuild. {item} is the
+				# only thing that's added for items, not
+				# trails, and it's harmless to delete that -
+				# the item is being rebuilt anyway.
+				delete $pagestate{$page}{trail};
+			}
+		}
+	}
+	return $needsbuild;
+}
+
+my $scanned = 0;
+
+sub preprocess_trailoptions (@) {
+	my %params = @_;
+
+	if (exists $params{circular}) {
+		$pagestate{$params{page}}{trail}{circular} =
+			IkiWiki::yesno($params{circular});
+	}
+
+	if (exists $params{sort}) {
+		$pagestate{$params{page}}{trail}{sort} = $params{sort};
+	}
+
+	if (exists $params{reverse}) {
+		$pagestate{$params{page}}{trail}{reverse} = $params{reverse};
+	}
+
+	return "";
+}
+
+sub preprocess_trailitem (@) {
+	my $link = shift;
+	shift;
+
+	# avoid collecting everything in the preprocess stage if we already
+	# did in the scan stage
+	if (defined wantarray) {
+		return "" if $scanned;
+	}
+	else {
+		$scanned = 1;
+	}
+
+	my %params = @_;
+	my $trail = $params{page};
+
+	$link = linkpage($link);
+
+	add_link($params{page}, $link, 'trail');
+	push @{$pagestate{$params{page}}{trail}{contents}}, [link => $link];
+
+	return "";
+}
+
+sub preprocess_trailitems (@) {
+	my %params = @_;
+
+	# avoid collecting everything in the preprocess stage if we already
+	# did in the scan stage
+	if (defined wantarray) {
+		return "" if $scanned;
+	}
+	else {
+		$scanned = 1;
+	}
+
+	# trail members from a pagespec ought to be in some sort of order,
+	# and path is a nice obvious default
+	$params{sort} = 'path' unless exists $params{sort};
+	$params{reverse} = 'no' unless exists $params{reverse};
+
+	if (exists $params{pages}) {
+		push @{$pagestate{$params{page}}{trail}{contents}},
+			["pagespec" => $params{pages}, $params{sort},
+				IkiWiki::yesno($params{reverse})];
+	}
+
+	if (exists $params{pagenames}) {
+		my @list = map { [link =>  $_] } split ' ', $params{pagenames};
+		push @{$pagestate{$params{page}}{trail}{contents}}, @list;
+	}
+
+	return "";
+}
+
+sub preprocess_traillink (@) {
+	my $link = shift;
+	shift;
+
+	my %params = @_;
+	my $trail = $params{page};
+
+	$link =~ qr{
+			(?:
+				([^\|]+)	# 1: link text
+				\|		# followed by |
+			)?			# optional
+
+			(.+)			# 2: page to link to
+		}x;
+
+	my $linktext = $1;
+	$link = linkpage($2);
+
+	add_link($params{page}, $link, 'trail');
+
+	# avoid collecting everything in the preprocess stage if we already
+	# did in the scan stage
+	my $already;
+	if (defined wantarray) {
+		$already = $scanned;
+	}
+	else {
+		$scanned = 1;
+	}
+
+	push @{$pagestate{$params{page}}{trail}{contents}}, [link => $link] unless $already;
+
+	if (defined $linktext) {
+		$linktext = pagetitle($linktext);
+	}
+
+	if (exists $params{text}) {
+		$linktext = $params{text};
+	}
+
+	if (defined $linktext) {
+		return htmllink($trail, $params{destpage},
+			$link, linktext => $linktext);
+	}
+
+	return htmllink($trail, $params{destpage}, $link);
+}
+
+# trail => [member1, member2]
+my %trail_to_members;
+# member => { trail => [prev, next] }
+# e.g. if %trail_to_members = (
+#	trail1 => ["member1", "member2"],
+#	trail2 => ["member0", "member1"],
+# )
+#
+# then $member_to_trails{member1} = {
+#	trail1 => [undef, "member2"],
+#	trail2 => ["member0", undef],
+# }
+my %member_to_trails;
+
+# member => 1
+my %rebuild_trail_members;
+
+sub trails_differ {
+	my ($old, $new) = @_;
+
+	foreach my $trail (keys %$old) {
+		if (! exists $new->{$trail}) {
+			return 1;
+		}
+		my ($old_p, $old_n) = @{$old->{$trail}};
+		my ($new_p, $new_n) = @{$new->{$trail}};
+		$old_p = "" unless defined $old_p;
+		$old_n = "" unless defined $old_n;
+		$new_p = "" unless defined $new_p;
+		$new_n = "" unless defined $new_n;
+		if ($old_p ne $new_p) {
+			return 1;
+		}
+		if ($old_n ne $new_n) {
+			return 1;
+		}
+	}
+
+	foreach my $trail (keys %$new) {
+		if (! exists $old->{$trail}) {
+			return 1;
+		}
+	}
+
+	return 0;
+}
+
+my $done_prerender = 0;
+
+sub prerender {
+	return if $done_prerender;
+
+	%trail_to_members = ();
+	%member_to_trails = ();
+
+	foreach my $trail (keys %pagestate) {
+		next unless exists $pagestate{$trail}{trail}{contents};
+
+		my $members = [];
+		my @contents = @{$pagestate{$trail}{trail}{contents}};
+
+		foreach my $c (@contents) {
+			if ($c->[0] eq 'pagespec') {
+				push @$members, pagespec_match_list($trail,
+					$c->[1], sort => $c->[2],
+					reverse => $c->[3]);
+			}
+			elsif ($c->[0] eq 'link') {
+				my $best = bestlink($trail, $c->[1]);
+				push @$members, $best if length $best;
+			}
+		}
+
+		if (defined $pagestate{$trail}{trail}{sort}) {
+			# re-sort
+			@$members = pagespec_match_list($trail, 'internal(*)',
+				list => $members,
+				sort => $pagestate{$trail}{trail}{sort});
+		}
+
+		if (IkiWiki::yesno $pagestate{$trail}{trail}{reverse}) {
+			@$members = reverse @$members;
+		}
+
+		# uniquify
+		my %seen;
+		my @tmp;
+		foreach my $member (@$members) {
+			push @tmp, $member unless $seen{$member};
+			$seen{$member} = 1;
+		}
+		$members = [@tmp];
+
+		for (my $i = 0; $i <= $#$members; $i++) {
+			my $member = $members->[$i];
+			my $prev;
+			$prev = $members->[$i - 1] if $i > 0;
+			my $next = $members->[$i + 1];
+
+			add_depends($member, $trail);
+
+			$member_to_trails{$member}{$trail} = [$prev, $next];
+		}
+
+		if ((scalar @$members) > 1 && $pagestate{$trail}{trail}{circular}) {
+			$member_to_trails{$members->[0]}{$trail}[0] = $members->[$#$members];
+			$member_to_trails{$members->[$#$members]}{$trail}[1] = $members->[0];
+		}
+
+		$trail_to_members{$trail} = $members;
+	}
+
+	foreach my $member (keys %pagestate) {
+		if (exists $pagestate{$member}{trail}{item} &&
+			! exists $member_to_trails{$member}) {
+			$rebuild_trail_members{$member} = 1;
+			delete $pagestate{$member}{trailitem};
+		}
+	}
+
+	foreach my $member (keys %member_to_trails) {
+		if (! exists $pagestate{$member}{trail}{item}) {
+			$rebuild_trail_members{$member} = 1;
+		}
+		else {
+			if (trails_differ($pagestate{$member}{trail}{item},
+					$member_to_trails{$member})) {
+				$rebuild_trail_members{$member} = 1;
+			}
+		}
+
+		$pagestate{$member}{trail}{item} = $member_to_trails{$member};
+	}
+
+	$done_prerender = 1;
+}
+
+sub build_affected {
+	my %affected;
+
+	foreach my $member (keys %rebuild_trail_members) {
+		$affected{$member} = sprintf(gettext("building %s, its previous or next page has changed"), $member);
+	}
+
+	return %affected;
+}
+
+sub title_of ($) {
+	my $page = shift;
+	if (defined ($pagestate{$page}{meta}{title})) {
+		return $pagestate{$page}{meta}{title};
+	}
+	return pagetitle(IkiWiki::basename($page));
+}
+
+my $recursive = 0;
+
+sub pagetemplate (@) {
+	my %params = @_;
+	my $page = $params{page};
+	my $template = $params{template};
+
+	if ($template->query(name => 'trails') && ! $recursive) {
+		prerender();
+
+		$recursive = 1;
+		my $inner = template("trails.tmpl", blind_cache => 1);
+		IkiWiki::run_hooks(pagetemplate => sub {
+				shift->(%params, template => $inner)
+			});
+		$template->param(trails => $inner->output);
+		$recursive = 0;
+	}
+
+	if ($template->query(name => 'trailloop')) {
+		prerender();
+
+		my @trails;
+
+		# sort backlinks by page name to have a consistent order
+		foreach my $trail (sort keys %{$member_to_trails{$page}}) {
+
+			my $members = $trail_to_members{$trail};
+			my ($prev, $next) = @{$member_to_trails{$page}{$trail}};
+			my ($prevurl, $nexturl, $prevtitle, $nexttitle);
+
+			if (defined $prev) {
+				add_depends($params{destpage}, $prev);
+				$prevurl = urlto($prev, $page);
+				$prevtitle = title_of($prev);
+			}
+
+			if (defined $next) {
+				add_depends($params{destpage}, $next);
+				$nexturl = urlto($next, $page);
+				$nexttitle = title_of($next);
+			}
+
+			push @trails, {
+				prevpage => $prev,
+				prevtitle => $prevtitle,
+				prevurl => $prevurl,
+				nextpage => $next,
+				nexttitle => $nexttitle,
+				nexturl => $nexturl,
+				trailpage => $trail,
+				trailtitle => title_of($trail),
+				trailurl => urlto($trail, $page),
+			};
+		}
+
+		$template->param(trailloop => \@trails);
+	}
+}
+
+1;
diff --git a/IkiWiki/Render.pm b/IkiWiki/Render.pm
index 05132a8a8..adb39a983 100644
--- a/IkiWiki/Render.pm
+++ b/IkiWiki/Render.pm
@@ -800,6 +800,14 @@ sub refresh () {
 		derender_internal($file);
 	}
 
+	run_hooks(build_affected => sub {
+		my %affected = shift->();
+		while (my ($page, $message) = each %affected) {
+			next unless exists $pagesources{$page};
+			render($pagesources{$page}, $message);
+		}
+	});
+
 	my ($backlinkchanged, $linkchangers)=calculate_changed_links($changed,
 		$del, $oldlink_targets);
 
diff --git a/auto-blog.setup b/auto-blog.setup
index 0eb83ded6..5617daf9e 100644
--- a/auto-blog.setup
+++ b/auto-blog.setup
@@ -36,7 +36,7 @@ IkiWiki::Setup::Automator->import(
 	cgiurl => "http://$domain/~$ENV{USER}/$wikiname_short/ikiwiki.cgi",
 	cgi_wrapper => "$ENV{HOME}/public_html/$wikiname_short/ikiwiki.cgi",
 	adminemail => "$ENV{USER}\@$domain",
-	add_plugins => [qw{goodstuff websetup comments blogspam calendar sidebar}],
+	add_plugins => [qw{goodstuff websetup comments blogspam calendar sidebar trail}],
 	disable_plugins => [qw{}],
 	libdir => "$ENV{HOME}/.ikiwiki",
 	rss => 1,
diff --git a/debian/changelog b/debian/changelog
index d6b71eaa3..3bc2a7e29 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -13,6 +13,10 @@ ikiwiki (3.20120203) UNRELEASED; urgency=low
     OpenStreetMap community for this utter awesomeness.
   * Add a few missing jquery UI icons to attachment upload widget underlay.
   * URI escape filename when generating the diffurl.
+  * trail: New plugin to add navigation trails through pages via Next and
+    Previous links. Trails can easily be added to existing inlines by setting
+    trail=yes in the inline.
+    Thanks to Simon McVittie for his persistance developing this feature.
 
  -- Joey Hess <joeyh@debian.org>  Wed, 08 Feb 2012 16:07:00 -0400
 
diff --git a/doc/examples/blog/posts.mdwn b/doc/examples/blog/posts.mdwn
index 08e014838..2bd0f1d6f 100644
--- a/doc/examples/blog/posts.mdwn
+++ b/doc/examples/blog/posts.mdwn
@@ -1,3 +1,3 @@
 Here is a full list of posts to the [[blog|index]].
 
-[[!inline pages="page(./posts/*) and !*/Discussion" archive=yes feedshow=10 quick=yes]]
+[[!inline pages="page(./posts/*) and !*/Discussion" archive=yes feedshow=10 quick=yes trail=yes]]
diff --git a/doc/ikiwiki/directive/inline.mdwn b/doc/ikiwiki/directive/inline.mdwn
index 22c18d9a1..4b11e5997 100644
--- a/doc/ikiwiki/directive/inline.mdwn
+++ b/doc/ikiwiki/directive/inline.mdwn
@@ -117,5 +117,10 @@ Here are some less often needed parameters:
   [[SubPage/LinkingRules]] as in a [[ikiwiki/WikiLink]]), and they are inlined
   in exactly the order given: the `sort` and `pages` parameters cannot be used
   in conjunction with this one.
+* `trail` - If the [[!iki plugins/trail desc=trail]] plugin is enabled, turn
+  the inlined pages into a trail with next/previous links, by passing the same
+  options to [[ikiwiki/directive/trailitems]]. The `skip` and `show` options
+  are ignored by the trail, so the next/previous links traverse through
+  all matching pages.
 
 [[!meta robots="noindex, follow"]]
diff --git a/doc/plugins/contrib/ikiwiki/directive/trailitem.mdwn b/doc/ikiwiki/directive/trailitem.mdwn
similarity index 75%
rename from doc/plugins/contrib/ikiwiki/directive/trailitem.mdwn
rename to doc/ikiwiki/directive/trailitem.mdwn
index 73b1985a5..59626b5a1 100644
--- a/doc/plugins/contrib/ikiwiki/directive/trailitem.mdwn
+++ b/doc/ikiwiki/directive/trailitem.mdwn
@@ -1,5 +1,5 @@
 The `trailitem` directive is supplied by the
-[[!iki plugins/contrib/trail desc=trail]] plugin. It is used like this:
+[[!iki plugins/trail desc=trail]] plugin. It is used like this:
 
     \[[!trailitem some_other_page]]
 
diff --git a/doc/plugins/contrib/ikiwiki/directive/trailitems.mdwn b/doc/ikiwiki/directive/trailitems.mdwn
similarity index 92%
rename from doc/plugins/contrib/ikiwiki/directive/trailitems.mdwn
rename to doc/ikiwiki/directive/trailitems.mdwn
index 4106ed33b..b1ba8d356 100644
--- a/doc/plugins/contrib/ikiwiki/directive/trailitems.mdwn
+++ b/doc/ikiwiki/directive/trailitems.mdwn
@@ -1,5 +1,5 @@
 The `trailitems` directive is supplied by the
-[[!iki plugins/contrib/trail desc=trail]] plugin. It adds pages
+[[!iki plugins/trail desc=trail]] plugin. It adds pages
 to the trail represented by the current page, without producing any output
 on that page.
 
diff --git a/doc/plugins/contrib/ikiwiki/directive/traillink.mdwn b/doc/ikiwiki/directive/traillink.mdwn
similarity index 93%
rename from doc/plugins/contrib/ikiwiki/directive/traillink.mdwn
rename to doc/ikiwiki/directive/traillink.mdwn
index 0e40e2411..090e2538d 100644
--- a/doc/plugins/contrib/ikiwiki/directive/traillink.mdwn
+++ b/doc/ikiwiki/directive/traillink.mdwn
@@ -1,5 +1,5 @@
 The `traillink` directive is supplied by the
-[[!iki plugins/contrib/trail desc=trail]]
+[[!iki plugins/trail desc=trail]]
 plugin. It generates a visible [[ikiwiki/WikiLink]], and also adds the
 linked page to the trail represented by the page containing the directive.
 
diff --git a/doc/plugins/contrib/ikiwiki/directive/trailoptions.mdwn b/doc/ikiwiki/directive/trailoptions.mdwn
similarity index 88%
rename from doc/plugins/contrib/ikiwiki/directive/trailoptions.mdwn
rename to doc/ikiwiki/directive/trailoptions.mdwn
index e1603f11b..d83f444c0 100644
--- a/doc/plugins/contrib/ikiwiki/directive/trailoptions.mdwn
+++ b/doc/ikiwiki/directive/trailoptions.mdwn
@@ -1,5 +1,5 @@
 The `trailoptions` directive is supplied by the
-[[!iki plugins/contrib/trail desc=trail]] plugin. It sets options for the
+[[!iki plugins/trail desc=trail]] plugin. It sets options for the
 trail represented by this page.
 
     \[[!trailoptions sort="meta(title)" circular="no"]]
diff --git a/doc/plugins/contrib/ikiwiki/directive/trailinline.mdwn b/doc/plugins/contrib/ikiwiki/directive/trailinline.mdwn
deleted file mode 100644
index 91d8a4edf..000000000
--- a/doc/plugins/contrib/ikiwiki/directive/trailinline.mdwn
+++ /dev/null
@@ -1,11 +0,0 @@
-The `trailinline` directive is provided by the
-[[!iki plugins/contrib/trail desc=trail]]
-plugin. It is equivalent to combining [[ikiwiki/directive/trailitems]] and
-[[ikiwiki/directive/inline]] directives with the same options.
-
-A typical use is to navigate through all posts in a blog:
-
-      \[[!trailinline pages="page(./posts/*) and !*/Discussion" archive=yes
-        feedshow=10 quick=yes]]
-
-[[!meta robots="noindex, follow"]]
diff --git a/doc/plugins/contrib/trail.mdwn b/doc/plugins/contrib/trail.mdwn
deleted file mode 100644
index 9d895783a..000000000
--- a/doc/plugins/contrib/trail.mdwn
+++ /dev/null
@@ -1,139 +0,0 @@
-[[!tag patch]]
-[[!template id=gitbranch branch=smcv/trail3-integrated author="[[smcv]]"]]
-
-Available from [[smcv]]'s git repository, in the `trail3` and `trail3-integrated` branches. This
-plugin aims to solve [[todo/wikitrails]] in a simpler way; it can also be
-used for [[navigation through blog posts|todo/Pagination_next_prev_links]].
-
-If you don't want to use a branch of ikiwiki, manual installation requires
-these files (use the "raw" link in gitweb to download):
-
-* [trail.pm](http://git.pseudorandom.co.uk/smcv/ikiwiki.git/blob/trail3:/IkiWiki/Plugin/trail.pm)
-  in an `IkiWiki/Plugin` subdirectory of your configured `plugindir`
-* [page.tmpl](http://git.pseudorandom.co.uk/smcv/ikiwiki.git/blob/trail3:/templates/page.tmpl)
-  and
-  [trails.tmpl](http://git.pseudorandom.co.uk/smcv/ikiwiki.git/blob/trail3:/templates/trails.tmpl)
-  in your configured `templatedir`, or a `templates` subdirectory of your wiki repository
-* the trail-related bits from the end of the
-  [stylesheet](http://git.pseudorandom.co.uk/smcv/ikiwiki.git/blob/trail3:/doc/style.css)
-  (put them in your local.css)
-* the trail-related bits at the end of the
-  [actiontabs](http://git.pseudorandom.co.uk/smcv/ikiwiki.git/blob/trail3:/themes/actiontabs/style.css)
-  or [blueview/goldtype](http://git.pseudorandom.co.uk/smcv/ikiwiki.git/blob/trail3:/themes/blueview/style.css)
-  stylesheets, if you use one of those themes (again, put them in your local.css)
-
-The branch also includes [[todo/test_coverage]] machinery.
-
-Demo:
-
-* [in use on entries in my blog](http://smcv.pseudorandom.co.uk/)
-* [a demo trail based on links](http://demo.hosted.pseudorandom.co.uk/trail/)
-* [a demo hybrid trail/inline](http://demo.hosted.pseudorandom.co.uk/trail2/)
-
-The page `e` is in both demo trails, to demonstrate how a page in more than
-one trail looks.
-
-The `smcv/trail2` branch is an older version of `trail3` which used typed links
-as its data structure, resulting in timing-related limitations (it couldn't
-select pages for the trail by using pagespecs, because pagespecs can't be
-evaluated correctly until the scan stage has finished).
-
-Updated, November 2011 (`trail3`):
-
-* reinstated `inline` integration ([[report]] integration would probably be
-  pretty easy too, if this gets merged)
-* switched from typed links back to a custom data structure to avoid
-  chicken/egg problems with ordering
-* create typed links too, as a side-effect, but not when using an inline
-* regression test with nearly full coverage
-* CSS for the default anti-theme and all built-in themes (it looks nicest
-  in the default anti-theme and in actiontabs - the demo uses actiontabs)
-
-Updated, March 2012 (`trail3-integrated`):
-
-* replaced `\[[!trailinline]]` with `\[[!inline trail=yes]]`
-* added a `build_affected` hook so it doesn't have to use `inject`
-  (optional commit, can be omitted)
-
-Known bugs:
-
-* the blueview and goldtype CSS nearly work, but the alignment is a bit off
-
-----
-
-[[!template id=plugin name=trail author="[[Simon_McVittie|smcv]]"]]
-[[!tag type/chrome]]
-
-This plugin provides the [[ikiwiki/directive/trailoptions]],
-[[ikiwiki/directive/traillink]], [[ikiwiki/directive/trailitem]],
-[[ikiwiki/directive/trailitems]]
-and [[ikiwiki/directive/trailinline]] [[directives|ikiwiki/directive]].
-
-It's sometimes useful to have "trails" of pages in a wiki where each
-page links to the next and/or previous page. For instance, you could use
-this for a guided tour, sequence of chapters, or sequence of blog posts.
-
-In this plugin, a trail is represented by a page, and the pages in the
-trail are indicated by specially marked links within that page, or by
-including groups of pages with a [[ikiwiki/directive]].
-
-If using the default `page.tmpl`, each page automatically displays the
-trails that it's a member of (if any), with links to the trail and to
-the next and previous members. HTML `<link>` tags with the `prev`,
-`next` and `up` relations are also generated.
-
-The [[ikiwiki/directive/trailoptions]] directive sets options for the
-entire trail.
-
-Pages can be included in a trail in various ways:
-
-* The [[ikiwiki/directive/trailinline]] directive sets up an [[inline]],
-  and at the same time adds the matching pages (from `pages` or `pagenames`)
-  to the trail. One use is to navigate through all posts in a blog:
-
-        \[[!trailinline pages="page(./posts/*) and !*/Discussion" archive=yes
-          feedshow=10 quick=yes]]
-
-  This directive only works if the [[!iki plugins/inline desc=inline]]
-  plugin is also enabled.
-
-* The [[ikiwiki/directive/trailitems]] directive has optional `pages` and
-  `pagenames` options which behave the same as in [[inline]], but don't
-  produce any output in the page, so you can have trails that don't list
-  all their pages.
-
-* The [[ikiwiki/directive/traillink]] directive makes a visible link
-  and also adds the linked page to the trail. This will typically be
-  used in a bullet list, but could also be in paragraph text:
-
-        * [[!traillink Introduction]]
-        * [[!traillink "Chapter 1"]]
-        * [[!traillink Chapter_2]]
-        * [[!traillink Appendix_A]]
-
-  or
-
-        To use this software you must \[[!traillink install]] it,
-        \[[!traillink configuration text="configure it"]],
-        and finally \[[!traillink running|run_it]].
-
-  This also counts as a [[ikiwiki/WikiLink]] for things like the `link()`
-  [[ikiwiki/PageSpec]] item.
-
-* The [[ikiwiki/directive/trailitem]] directive adds a page to the trail
-  like `traillink`, but produces an invisible link, rather like `\[[!tag]]`:
-
-        To use this software you must \[[!traillink install]] it,
-        \[[!trailitem installing_from_packages]]
-        \[[!trailitem installing_from_source]]
-        \[[!traillink configuration text="configure it"]],
-        and finally \[[!traillink running|run_it]].
-        \[[!trailitem troubleshooting]]
-
-  Like `\[[!tag]]`, this still counts as a [[ikiwiki/WikiLink]] even though
-  there's no visible link.
-
-You can mix several of these directives in one page. The resulting
-trail will contain all of the pages matched by any of the directives,
-in the same order that the directives appear (unless you use the `sort` or
-`reverse` options on `\[[!trailoptions]]`).
diff --git a/doc/plugins/trail.mdwn b/doc/plugins/trail.mdwn
new file mode 100644
index 000000000..14b97e35a
--- /dev/null
+++ b/doc/plugins/trail.mdwn
@@ -0,0 +1,76 @@
+[[!template id=plugin name=trail author="[[Simon_McVittie|smcv]]"]]
+[[!tag type/chrome]]
+
+This plugin provides the [[ikiwiki/directive/trailoptions]],
+[[ikiwiki/directive/traillink]], [[ikiwiki/directive/trailitem]],
+and [[ikiwiki/directive/trailitems]] [[directives|ikiwiki/directive]].
+
+It's sometimes useful to have "trails" of pages in a wiki where each
+page links to the next and/or previous page. For instance, you could use
+this for a guided tour, sequence of chapters, or sequence of blog posts.
+
+In this plugin, a trail is represented by a page, and the pages in the
+trail are indicated by specially marked links within that page, or by
+including groups of pages with a [[ikiwiki/directive]].
+
+If using the default `page.tmpl`, each page automatically displays the
+trails that it's a member of (if any), with links to the trail and to
+the next and previous members. HTML `<link>` tags with the `prev`,
+`next` and `up` relations are also generated.
+
+The [[ikiwiki/directive/trailoptions]] directive sets options for the
+entire trail.
+
+Pages can be included in a trail in various ways:
+
+* The [[ikiwiki/directive/inline]] directive with `trail="yes"` sets up an
+  [[inline]], and at the same time adds the matching pages (from `pages` or
+  `pagenames`) to the trail. One use is to navigate through all posts in
+  a blog:
+
+        \[[!inline pages="page(./posts/*) and !*/Discussion" archive=yes
+          feedshow=10 quick=yes trail=yes]]
+
+  This only works if the trail and [[!iki plugins/inline desc=inline]]
+  plugins are both enabled.
+
+* The [[ikiwiki/directive/trailitems]] directive has optional `pages` and
+  `pagenames` options which behave the same as in [[inline]], but don't
+  produce any output in the page, so you can have trails that don't list
+  all their pages.
+
+* The [[ikiwiki/directive/traillink]] directive makes a visible link
+  and also adds the linked page to the trail. This will typically be
+  used in a bullet list, but could also be in paragraph text:
+
+        * [[!traillink Introduction]]
+        * [[!traillink "Chapter 1"]]
+        * [[!traillink Chapter_2]]
+        * [[!traillink Appendix_A]]
+
+  or
+
+        To use this software you must \[[!traillink install]] it,
+        \[[!traillink configuration text="configure it"]],
+        and finally \[[!traillink running|run_it]].
+
+  This also counts as a [[ikiwiki/WikiLink]] for things like the `link()`
+  [[ikiwiki/PageSpec]] item.
+
+* The [[ikiwiki/directive/trailitem]] directive adds a page to the trail
+  like `traillink`, but produces an invisible link, rather like `\[[!tag]]`:
+
+        To use this software you must \[[!traillink install]] it,
+        \[[!trailitem installing_from_packages]]
+        \[[!trailitem installing_from_source]]
+        \[[!traillink configuration text="configure it"]],
+        and finally \[[!traillink running|run_it]].
+        \[[!trailitem troubleshooting]]
+
+  Like `\[[!tag]]`, this still counts as a [[ikiwiki/WikiLink]] even though
+  there's no visible link.
+
+You can mix several of these directives in one page. The resulting
+trail will contain all of the pages matched by any of the directives,
+in the same order that the directives appear (unless you use the `sort` or
+`reverse` options on `\[[!trailoptions]]`).
diff --git a/doc/plugins/write.mdwn b/doc/plugins/write.mdwn
index dcab041dc..d62ab6e63 100644
--- a/doc/plugins/write.mdwn
+++ b/doc/plugins/write.mdwn
@@ -356,6 +356,22 @@ when the page is being previewed.)
 The function is passed named parameters: "page" and "content", and 
 should return the formatted content.
 
+### build_affected
+
+	hook(type => "build_affected", id => "foo", call => \&build_affected);
+
+This hook is called after the directly changed pages have been built,
+and can cause extra pages to be built. If links and backlinks were provided
+by a plugin, this would be where that plugin would rebuild pages whose
+backlinks have changed, for instance. The [[trail]] plugin uses this hook
+to rebuild pages whose next or previous page has changed.
+
+The function should currently ignore its parameters. It returns a list with
+an even number of items (a hash in list context), where the first item of
+each pair is a page name to be rebuilt (if it was not already rebuilt), and
+the second is a log message resembling
+`building plugins/write because the phase of the moon has changed`.
+
 ### delete
 
 	hook(type => "delete", id => "foo", call => \&delete);
diff --git a/doc/style.css b/doc/style.css
index 7bbfe5d2a..35a133198 100644
--- a/doc/style.css
+++ b/doc/style.css
@@ -501,3 +501,38 @@ a.openid_large_btn:focus {
 .fileupload-content .ui-progressbar-value {
 	background: url(ikiwiki/images/pbar-ani.gif);
 }
+
+.trail {
+	display: block;
+	clear: both;
+	position: relative;
+}
+
+.trailprev {
+	display: block;
+	text-align: left;
+	position: absolute;
+	top: 0%;
+	left: 3%;
+	width: 30%;
+}
+
+.trailup {
+	display: block;
+	text-align: center;
+	margin-left: 35%;
+	margin-right: 35%;
+}
+
+.trailnext {
+	display: block;
+	text-align: right;
+	position: absolute;
+	top: 0%;
+	width: 30%;
+	right: 3%;
+}
+
+.trailsep {
+	display: none;
+}
diff --git a/doc/templates.mdwn b/doc/templates.mdwn
index d189fa073..43bf9ee51 100644
--- a/doc/templates.mdwn
+++ b/doc/templates.mdwn
@@ -80,6 +80,8 @@ Here is a full list of the template files used:
 * `autotag.tmpl` - Filled in by the tag plugin to make tag pages.
 * `calendarmonth.tmpl`, `calendaryear.tmpl` - Used by ikiwiki-calendar to
   make calendar archive pages.
+* `trails.tmpl` - Used by the trail plugin to generate links on each page
+  that is a member of a trail.
 * `editpage.tmpl`, `editconflict.tmpl`, `editcreationconflict.tmpl`,
   `editfailedsave.tmpl`, `editpagegone.tmpl`, `pocreatepage.tmpl`,
   `editcomment.tmpl` `commentmoderation.tmpl`, `renamesummary.tmpl`,
diff --git a/t/trail.t b/t/trail.t
new file mode 100755
index 000000000..17fe54310
--- /dev/null
+++ b/t/trail.t
@@ -0,0 +1,233 @@
+#!/usr/bin/perl
+use warnings;
+use strict;
+use Test::More 'no_plan';
+use IkiWiki;
+
+my $blob;
+
+ok(! system("rm -rf t/tmp"));
+ok(! system("mkdir t/tmp"));
+
+# Use a rather stylized template to override the default rendering, to make
+# it easy to search for the desired results
+writefile("templates/trails.tmpl", "t/tmp/in", <<EOF
+<TMPL_LOOP TRAILLOOP>
+<TMPL_IF __FIRST__><nav></TMPL_IF>
+<div>
+trail=<TMPL_VAR TRAILPAGE> n=<TMPL_VAR NEXTPAGE> p=<TMPL_VAR PREVPAGE>
+</div>
+<div>
+<TMPL_IF PREVURL>
+<a href="<TMPL_VAR PREVURL>">&lt; <TMPL_VAR PREVTITLE></a>
+</TMPL_IF> |
+<a href="<TMPL_VAR TRAILURL>">^ <TMPL_VAR TRAILTITLE> ^</a>
+| <TMPL_IF NEXTURL>
+<a href="<TMPL_VAR NEXTURL>"><TMPL_VAR NEXTTITLE> &gt;</a>
+</TMPL_IF>
+</div>
+<TMPL_IF __LAST__></nav></TMPL_IF>
+</TMPL_LOOP>
+EOF
+);
+writefile("badger.mdwn", "t/tmp/in", "[[!meta title=\"The Breezy Badger\"]]\ncontent of badger");
+writefile("mushroom.mdwn", "t/tmp/in", "content of mushroom");
+writefile("snake.mdwn", "t/tmp/in", "content of snake");
+writefile("ratty.mdwn", "t/tmp/in", "content of ratty");
+writefile("mr_toad.mdwn", "t/tmp/in", "content of mr toad");
+writefile("add.mdwn", "t/tmp/in", '[[!trailitems pagenames="add/a add/b add/c add/d add/e"]]');
+writefile("add/b.mdwn", "t/tmp/in", "b");
+writefile("add/d.mdwn", "t/tmp/in", "d");
+writefile("del.mdwn", "t/tmp/in", '[[!trailitems pages="del/*" sort=title]]');
+writefile("del/a.mdwn", "t/tmp/in", "a");
+writefile("del/b.mdwn", "t/tmp/in", "b");
+writefile("del/c.mdwn", "t/tmp/in", "c");
+writefile("del/d.mdwn", "t/tmp/in", "d");
+writefile("del/e.mdwn", "t/tmp/in", "e");
+writefile("self_referential.mdwn", "t/tmp/in", '[[!trailitems pagenames="self_referential" circular=yes]]');
+writefile("sorting/linked.mdwn", "t/tmp/in", "linked");
+writefile("sorting/a/b.mdwn", "t/tmp/in", "a/b");
+writefile("sorting/a/c.mdwn", "t/tmp/in", "a/c");
+writefile("sorting/z/a.mdwn", "t/tmp/in", "z/a");
+writefile("sorting/beginning.mdwn", "t/tmp/in", "beginning");
+writefile("sorting/middle.mdwn", "t/tmp/in", "middle");
+writefile("sorting/end.mdwn", "t/tmp/in", "end");
+writefile("sorting/new.mdwn", "t/tmp/in", "new");
+writefile("sorting/old.mdwn", "t/tmp/in", "old");
+writefile("sorting/ancient.mdwn", "t/tmp/in", "ancient");
+# These three need to be in the appropriate age order
+ok(utime(333333333, 333333333, "t/tmp/in/sorting/new.mdwn"));
+ok(utime(222222222, 222222222, "t/tmp/in/sorting/old.mdwn"));
+ok(utime(111111111, 111111111, "t/tmp/in/sorting/ancient.mdwn"));
+writefile("sorting/linked2.mdwn", "t/tmp/in", "linked2");
+# This initially uses the default sort order: age for the inline, and path
+# for trailitems. We change it later.
+writefile("sorting.mdwn", "t/tmp/in",
+	'[[!traillink linked]] ' .
+	'[[!trailitems pages="sorting/z/a or sorting/a/b or sorting/a/c"]] ' .
+	'[[!trailitems pagenames="beginning middle end"]] ' .
+	'[[!inline pages="sorting/old or sorting/ancient or sorting/new" trail="yes"]] ' .
+	'[[!traillink linked2]]');
+
+writefile("meme.mdwn", "t/tmp/in", <<EOF
+[[!trail]]
+* [[!traillink badger]]
+* [[!traillink badger text="This is a link to badger, with a title"]]
+* [[!traillink That_is_the_badger|badger]]
+* [[!traillink badger]]
+* [[!traillink mushroom]]
+* [[!traillink mushroom]]
+* [[!traillink snake]]
+* [[!traillink snake]]
+EOF
+);
+
+writefile("wind_in_the_willows.mdwn", "t/tmp/in", <<EOF
+[[!trailoptions circular=yes sort=title]]
+[[!trailitems pages="ratty or badger or mr_toad"]]
+[[!trailitem moley]]
+EOF
+);
+
+ok(! system("make -s ikiwiki.out"));
+
+my $command = "perl -I. ./ikiwiki.out -set usedirs=0 -plugin trail -plugin inline -url=http://example.com -cgiurl=http://example.com/ikiwiki.cgi -rss -atom -underlaydir=underlays/basewiki -set underlaydirbase=underlays -templatedir=templates t/tmp/in t/tmp/out -verbose";
+
+ok(! system($command));
+
+ok(! system("$command -refresh"));
+
+$blob = readfile("t/tmp/out/meme.html");
+ok($blob =~ /<a href="(\.\/)?badger.html">badger<\/a>/m);
+ok($blob =~ /<a href="(\.\/)?badger.html">This is a link to badger, with a title<\/a>/m);
+ok($blob =~ /<a href="(\.\/)?badger.html">That is the badger<\/a>/m);
+
+$blob = readfile("t/tmp/out/badger.html");
+ok($blob =~ /^trail=meme n=mushroom p=$/m);
+ok($blob =~ /^trail=wind_in_the_willows n=mr_toad p=ratty$/m);
+
+ok(! -f "t/tmp/out/moley.html");
+
+$blob = readfile("t/tmp/out/mr_toad.html");
+ok($blob !~ /^trail=meme/m);
+ok($blob =~ /^trail=wind_in_the_willows n=ratty p=badger$/m);
+# meta title is respected for pages that have one
+ok($blob =~ /">&lt; The Breezy Badger<\/a>/m);
+# pagetitle for pages that don't
+ok($blob =~ /">ratty &gt;<\/a>/m);
+
+$blob = readfile("t/tmp/out/ratty.html");
+ok($blob !~ /^trail=meme/m);
+ok($blob =~ /^trail=wind_in_the_willows n=badger p=mr_toad$/m);
+
+$blob = readfile("t/tmp/out/mushroom.html");
+ok($blob =~ /^trail=meme n=snake p=badger$/m);
+ok($blob !~ /^trail=wind_in_the_willows/m);
+
+$blob = readfile("t/tmp/out/snake.html");
+ok($blob =~ /^trail=meme n= p=mushroom$/m);
+ok($blob !~ /^trail=wind_in_the_willows/m);
+
+$blob = readfile("t/tmp/out/self_referential.html");
+ok($blob =~ /^trail=self_referential n= p=$/m);
+
+$blob = readfile("t/tmp/out/add/b.html");
+ok($blob =~ /^trail=add n=add\/d p=$/m);
+$blob = readfile("t/tmp/out/add/d.html");
+ok($blob =~ /^trail=add n= p=add\/b$/m);
+ok(! -f "t/tmp/out/add/a.html");
+ok(! -f "t/tmp/out/add/c.html");
+ok(! -f "t/tmp/out/add/e.html");
+
+$blob = readfile("t/tmp/out/del/a.html");
+ok($blob =~ /^trail=del n=del\/b p=$/m);
+$blob = readfile("t/tmp/out/del/b.html");
+ok($blob =~ /^trail=del n=del\/c p=del\/a$/m);
+$blob = readfile("t/tmp/out/del/c.html");
+ok($blob =~ /^trail=del n=del\/d p=del\/b$/m);
+$blob = readfile("t/tmp/out/del/d.html");
+ok($blob =~ /^trail=del n=del\/e p=del\/c$/m);
+$blob = readfile("t/tmp/out/del/e.html");
+ok($blob =~ /^trail=del n= p=del\/d$/m);
+
+$blob = readfile("t/tmp/out/sorting/linked.html");
+ok($blob =~ m{^trail=sorting n=sorting/a/b p=$}m);
+$blob = readfile("t/tmp/out/sorting/a/b.html");
+ok($blob =~ m{^trail=sorting n=sorting/a/c p=sorting/linked$}m);
+$blob = readfile("t/tmp/out/sorting/a/c.html");
+ok($blob =~ m{^trail=sorting n=sorting/z/a p=sorting/a/b$}m);
+$blob = readfile("t/tmp/out/sorting/z/a.html");
+ok($blob =~ m{^trail=sorting n=sorting/beginning p=sorting/a/c$}m);
+$blob = readfile("t/tmp/out/sorting/beginning.html");
+ok($blob =~ m{^trail=sorting n=sorting/middle p=sorting/z/a$}m);
+$blob = readfile("t/tmp/out/sorting/middle.html");
+ok($blob =~ m{^trail=sorting n=sorting/end p=sorting/beginning$}m);
+$blob = readfile("t/tmp/out/sorting/end.html");
+ok($blob =~ m{^trail=sorting n=sorting/new p=sorting/middle$}m);
+$blob = readfile("t/tmp/out/sorting/new.html");
+ok($blob =~ m{^trail=sorting n=sorting/old p=sorting/end$}m);
+$blob = readfile("t/tmp/out/sorting/old.html");
+ok($blob =~ m{^trail=sorting n=sorting/ancient p=sorting/new$}m);
+$blob = readfile("t/tmp/out/sorting/ancient.html");
+ok($blob =~ m{^trail=sorting n=sorting/linked2 p=sorting/old$}m);
+$blob = readfile("t/tmp/out/sorting/linked2.html");
+ok($blob =~ m{^trail=sorting n= p=sorting/ancient$}m);
+
+# Make some changes and refresh
+
+writefile("add/a.mdwn", "t/tmp/in", "a");
+writefile("add/c.mdwn", "t/tmp/in", "c");
+writefile("add/e.mdwn", "t/tmp/in", "e");
+ok(unlink("t/tmp/in/del/a.mdwn"));
+ok(unlink("t/tmp/in/del/c.mdwn"));
+ok(unlink("t/tmp/in/del/e.mdwn"));
+
+writefile("sorting.mdwn", "t/tmp/in",
+	readfile("t/tmp/in/sorting.mdwn") .
+	'[[!trailoptions sort="title" reverse="yes"]]'); 
+
+ok(! system("$command -refresh"));
+
+$blob = readfile("t/tmp/out/add/a.html");
+ok($blob =~ /^trail=add n=add\/b p=$/m);
+$blob = readfile("t/tmp/out/add/b.html");
+ok($blob =~ /^trail=add n=add\/c p=add\/a$/m);
+$blob = readfile("t/tmp/out/add/c.html");
+ok($blob =~ /^trail=add n=add\/d p=add\/b$/m);
+$blob = readfile("t/tmp/out/add/d.html");
+ok($blob =~ /^trail=add n=add\/e p=add\/c$/m);
+$blob = readfile("t/tmp/out/add/e.html");
+ok($blob =~ /^trail=add n= p=add\/d$/m);
+
+$blob = readfile("t/tmp/out/del/b.html");
+ok($blob =~ /^trail=del n=del\/d p=$/m);
+$blob = readfile("t/tmp/out/del/d.html");
+ok($blob =~ /^trail=del n= p=del\/b$/m);
+ok(! -f "t/tmp/out/del/a.html");
+ok(! -f "t/tmp/out/del/c.html");
+ok(! -f "t/tmp/out/del/e.html");
+
+$blob = readfile("t/tmp/out/sorting/old.html");
+ok($blob =~ m{^trail=sorting n=sorting/new p=$}m);
+$blob = readfile("t/tmp/out/sorting/new.html");
+ok($blob =~ m{^trail=sorting n=sorting/middle p=sorting/old$}m);
+$blob = readfile("t/tmp/out/sorting/middle.html");
+ok($blob =~ m{^trail=sorting n=sorting/linked2 p=sorting/new$}m);
+$blob = readfile("t/tmp/out/sorting/linked2.html");
+ok($blob =~ m{^trail=sorting n=sorting/linked p=sorting/middle$}m);
+$blob = readfile("t/tmp/out/sorting/linked.html");
+ok($blob =~ m{^trail=sorting n=sorting/end p=sorting/linked2$}m);
+$blob = readfile("t/tmp/out/sorting/end.html");
+ok($blob =~ m{^trail=sorting n=sorting/a/c p=sorting/linked$}m);
+$blob = readfile("t/tmp/out/sorting/a/c.html");
+ok($blob =~ m{^trail=sorting n=sorting/beginning p=sorting/end$}m);
+$blob = readfile("t/tmp/out/sorting/beginning.html");
+ok($blob =~ m{^trail=sorting n=sorting/a/b p=sorting/a/c$}m);
+$blob = readfile("t/tmp/out/sorting/a/b.html");
+ok($blob =~ m{^trail=sorting n=sorting/ancient p=sorting/beginning$}m);
+$blob = readfile("t/tmp/out/sorting/ancient.html");
+ok($blob =~ m{^trail=sorting n=sorting/z/a p=sorting/a/b$}m);
+$blob = readfile("t/tmp/out/sorting/z/a.html");
+ok($blob =~ m{^trail=sorting n= p=sorting/ancient$}m);
+
+ok(! system("rm -rf t/tmp"));
diff --git a/templates/page.tmpl b/templates/page.tmpl
index 8659018a0..770ac2399 100644
--- a/templates/page.tmpl
+++ b/templates/page.tmpl
@@ -27,6 +27,15 @@
 <TMPL_IF FEEDLINKS><TMPL_VAR FEEDLINKS></TMPL_IF>
 <TMPL_IF RELVCS><TMPL_VAR RELVCS></TMPL_IF>
 <TMPL_IF META><TMPL_VAR META></TMPL_IF>
+<TMPL_LOOP TRAILLOOP>
+<TMPL_IF PREVPAGE>
+<link rel="prev" href="<TMPL_VAR PREVURL>" title="<TMPL_VAR PREVTITLE>" />
+</TMPL_IF>
+<link rel="up" href="<TMPL_VAR TRAILURL>" title="<TMPL_VAR TRAILTITLE>" />
+<TMPL_IF NEXTPAGE>
+<link rel="next" href="<TMPL_VAR NEXTURL>" title="<TMPL_VAR NEXTTITLE>" />
+</TMPL_IF>
+</TMPL_LOOP>
 </head>
 <body>
 
@@ -103,6 +112,8 @@
 <TMPL_IF HTML5></nav><TMPL_ELSE></div></TMPL_IF>
 </TMPL_IF>
 
+<TMPL_VAR TRAILS>
+
 <TMPL_IF HTML5></section><TMPL_ELSE></div></TMPL_IF>
 
 <TMPL_IF SIDEBAR>
diff --git a/templates/trails.tmpl b/templates/trails.tmpl
new file mode 100644
index 000000000..54c046043
--- /dev/null
+++ b/templates/trails.tmpl
@@ -0,0 +1,23 @@
+<TMPL_LOOP TRAILLOOP>
+<TMPL_IF __FIRST__><TMPL_IF HTML5><nav class="trails"><TMPL_ELSE><div class="trails"></TMPL_IF></TMPL_IF>
+<div class="trail">
+<TMPL_IF PREVPAGE>
+<span class="trailprev">
+<span class="trailarrow">←</span>
+<a href="<TMPL_VAR PREVURL>"><TMPL_VAR PREVTITLE></a>
+<span class="trailsep">|</span>
+</span>
+</TMPL_IF>
+<span class="trailup">
+<a href="<TMPL_VAR TRAILURL>"><TMPL_VAR TRAILTITLE></a>
+</span>
+<TMPL_IF NEXTPAGE>
+<span class="trailnext">
+<span class="trailsep">|</span>
+<a href="<TMPL_VAR NEXTURL>"><TMPL_VAR NEXTTITLE></a>
+<span class="trailarrow">→</span>
+</span>
+</TMPL_IF>
+</div>
+<TMPL_IF __LAST__><TMPL_IF HTML5></nav><TMPL_ELSE></div></TMPL_IF></TMPL_IF>
+</TMPL_LOOP>
diff --git a/themes/actiontabs/style.css b/themes/actiontabs/style.css
index 749d9b21e..26cdc1e86 100644
--- a/themes/actiontabs/style.css
+++ b/themes/actiontabs/style.css
@@ -142,3 +142,8 @@ div.recentchanges {
 	padding: 0 0 0 2ex;
 	border-color: #999;
 }
+
+.trails {
+	/* allow space for the action tabs */
+	margin-bottom: 2em;
+}
diff --git a/themes/blueview/style.css b/themes/blueview/style.css
index c07d1cdfa..32f4b32ea 100644
--- a/themes/blueview/style.css
+++ b/themes/blueview/style.css
@@ -197,18 +197,23 @@ body {
 	font-weight: bold;
 }
 
-.pageheader .header .title, .pageheader .header .parentlinks, .pageheader .actions ul li, .pageheader .header span, .pageheader #otherlanguages ul li {
+.pageheader .header .title, .pageheader .header .parentlinks, .pageheader .actions ul li, .pageheader .header span, .pageheader #otherlanguages ul li, .trailprev, .trailnext, .trailup {
 	padding: 0.25em 0.25em 0.25em 0.25em;
 	background-image: url('background_darkness.png');
 	background-repeat: repeat;
 	color: white;
 }
 
-.pageheader .header span a, .pageheader .actions ul li a, .pageheader .header .parentlinks a, .pageheader #otherlanguages ul li a {
+.pageheader .header span a, .pageheader .actions ul li a, .pageheader .header .parentlinks a, .pageheader #otherlanguages ul li a, .pageheader a {
+	font-weight: bold;
 	color: white;
 	text-decoration: none;
 }
 
+.trailprev, .trailnext, .trailup {
+	margin-top: 0.5em;
+}
+
 .pageheader .actions {
 	text-align: right;
 	vertical-align: bottom;