Add an optional "sort" argument to meta titles, defaulting to the title

This allows correct sorting of titles, names, etc., with:

    [[!meta title="David Bowie" sort="Bowie, David"]]
    [[!meta title="The Beatles" sort="Beatles, The"]]

3 files changed, 22 insertions, 8 deletions

diff --git a/IkiWiki/Plugin/meta.pm b/IkiWiki/Plugin/meta.pm
index bf8159814..a470041c9 100644
--- a/IkiWiki/Plugin/meta.pm
+++ b/IkiWiki/Plugin/meta.pm
@@ -90,6 +90,12 @@ sub preprocess (@) {
 	# Metadata collection that needs to happen during the scan pass.
 	if ($key eq 'title') {
 		$pagestate{$page}{meta}{title}=HTML::Entities::encode_numeric($value);
+		if (exists $params{sort}) {
+			$pagestate{$page}{meta}{titlesort}=$params{sort};
+		}
+		else {
+			$pagestate{$page}{meta}{titlesort}=$value;
+		}
 		return "";
 	}
 	elsif ($key eq 'description') {
@@ -283,18 +289,18 @@ sub pagetemplate (@) {
 	}
 }
 
-sub title {
-	my $title = $pagestate{$_[0]}{meta}{title};
+sub titlesort {
+	my $key = $pagestate{$_[0]}{meta}{titlesort};
 
-	if (defined $title) {
-		return $title;
+	if (defined $key) {
+		return $key;
 	}
 
 	return pagetitle(IkiWiki::basename($_[0]));
 }
 
 sub sort_meta_title {
-	return title($_[0]) cmp title($_[1]);
+	return titlesort($_[0]) cmp titlesort($_[1]);
 }
 
 sub match {
diff --git a/doc/ikiwiki/directive/meta.mdwn b/doc/ikiwiki/directive/meta.mdwn
index 557441c0b..8d2a5b1ad 100644
--- a/doc/ikiwiki/directive/meta.mdwn
+++ b/doc/ikiwiki/directive/meta.mdwn
@@ -23,6 +23,13 @@ Supported fields:
   be set to a true value in the template; this can be used to format things
   differently in this case.
 
+  An optional `sort` parameter will be used preferentially when
+  [[ikiwiki/pagespec/sorting]] by `meta_title`:
+
+	\[[!meta title="The Beatles" sort="Beatles, The"]]
+
+	\[[!meta title="David Bowie" sort="Bowie, David"]]
+
 * license
 
   Specifies a license for the page, for example, "GPL". Can contain
diff --git a/doc/ikiwiki/pagespec/sorting.mdwn b/doc/ikiwiki/pagespec/sorting.mdwn
index 3a9fef9b6..61516bec5 100644
--- a/doc/ikiwiki/pagespec/sorting.mdwn
+++ b/doc/ikiwiki/pagespec/sorting.mdwn
@@ -5,13 +5,14 @@ orders can be specified.
 
 * `age` - List pages from the most recently created to the oldest.
 * `mtime` - List pages with the most recently modified first.
-* `title` - Order by title.
+* `title` - Order by title (page name).
 * `title_natural` - Only available if [[!cpan Sort::Naturally]] is
   installed. Orders by title, but numbers in the title are treated
   as such, ("1 2 9 10 20" instead of "1 10 2 20 9")
 [[!if test="enabled(meta)" then="""
-* `meta_title` - Order by the full title set by the `\[[!meta title="foo"]]`
-  [[ikiwiki/directive]].
+* `meta_title` - Order according to the `\[[!meta title="foo" sort="bar"]]`
+  or `\[[!meta title="foo"]]` [[ikiwiki/directive]], or the page name if no
+  full title was set.
 """]]
 
 Plugins can add additional sort orders, so more might be available on this