--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Yuki/DiffText.pm	Sun Jun 06 22:00:38 2010 +0900
@@ -0,0 +1,90 @@
+package Yuki::DiffText;
+use strict;
+use Algorithm::Diff qw(traverse_sequences);
+use vars qw($VERSION @EXPORT_OK @ISA);
+use vars qw($diff_text $diff_msgrefA $diff_msgrefB @diff_deleted @diff_added);
+require Exporter;
+@ISA = qw(Exporter);
+@EXPORT_OK = qw(difftext);
+$VERSION = '0.1';
+
+=head1 NAME
+
+Yuki::DiffText - A wrapper of Algorithm::Diff for YukiWiki.
+
+=head1 SYNOPSIS
+
+    use strict;
+    use Yuki::DiffText qw(difftext);
+
+    my @array1 = ( "Alice", "Bobby", "Chris", );
+    my @array2 = ( "Alice",          "Chris", "Diana", );
+    my $difftext = difftext(\@array1, \@array2);
+    print $difftext;
+
+    # Result:
+    # =Alice
+    # -Bobby
+    # =Chris
+    # +Diana
+
+=head1 SEE ALSO
+
+=over 4
+
+=item L<Algorithm::Diff>
+
+=back
+
+=head1 AUTHOR
+
+Hiroshi Yuki <hyuki@hyuki.com> http://www.hyuki.com/
+
+=head1 LICENSE
+
+Copyright (C) 2002 by Hiroshi Yuki.
+
+This program is free software; you can redistribute it and/or
+modify it under the same terms as Perl itself.
+
+=cut
+
+sub difftext {
+    ($diff_msgrefA, $diff_msgrefB) = @_;
+    undef $diff_text;
+    undef @diff_deleted;
+    undef @diff_added;
+    traverse_sequences(
+        $diff_msgrefA, $diff_msgrefB,
+        {
+            MATCH => \&df_match,
+            DISCARD_A => \&df_delete,
+            DISCARD_B => \&df_add,
+        }
+    );
+    &diff_flush;
+    return $diff_text;
+}
+
+sub diff_flush {
+    $diff_text .= join('', map { "-$_\n" } splice(@diff_deleted));
+    $diff_text .= join('', map { "+$_\n" } splice(@diff_added));
+}
+
+sub df_match {
+    my ($a, $b) = @_;
+    &diff_flush;
+    $diff_text .= "=$diff_msgrefA->[$a]\n";
+}
+
+sub df_delete {
+    my ($a, $b) = @_;
+    push(@diff_deleted, $diff_msgrefA->[$a]);
+}
+
+sub df_add {
+    my ($a, $b) = @_;
+    push(@diff_added, $diff_msgrefB->[$b]);
+}
+
+1;