display the pagetitle() in linkmaps

without this patch, linkmaps display underscores and underscore escape
sequences in the rendered output.

this introduces a pageescape function, which invoces pagetitle() to get
rid of underscore escapes and wraps the resulting utf8 string
appropriately for inclusion in a dot file (using dot's html encoding
because it can represent the '\"' dyad properly, and because it doesn't
need special-casing of newlines).

IkiWiki/Plugin/linkmap.pm

@@ -5,6 +5,7 @@ use warnings;
 use strict;
 use IkiWiki 3.00;
 use IPC::Open2;
+use HTML::Entities;
 
 sub import {
 	hook(type => "getsetup", id => "linkmap", call => \&getsetup);
@@ -22,6 +23,18 @@ sub getsetup () {
 
 my $mapnum=0;
 
+sub pageescape {
+	my $item = shift;
+	# encoding explicitly in case ikiwiki is configured to accept <> or &
+	# in file names
+	my $title = pagetitle($item, 1);
+	# it would not be necessary to encode *all* the html entities (<> would
+	# be sufficient, &" probably a good idea), as dot accepts utf8, but it
+	# isn't bad either
+	$title = encode_entities($title);
+	return("<$title>");
+}
+
 sub preprocess (@) {
 	my %params=@_;
 
@@ -63,7 +76,7 @@ sub preprocess (@) {
 	my $show=sub {
 		my $item=shift;
 		if (! $shown{$item}) {
-			print OUT "\"$item\" [shape=box,href=\"$mapitems{$item}\"];\n";
+			print OUT pageescape($item)." [shape=box,href=\"$mapitems{$item}\"];\n";
 			$shown{$item}=1;
 		}
 	};
@@ -74,7 +87,7 @@ sub preprocess (@) {
 			foreach my $endpoint ($item, $link) {
 				$show->($endpoint);
 			}
-			print OUT "\"$item\" -> \"$link\";\n";
+			print OUT pageescape($item)." -> ".pageescape($link).";\n";
 		}
 	}
 	print OUT "}\n";