Replaced diff.rb with xhtmldiff.rb, which (unlike its predecessor) produces well-formed redline documents.

lib/diff/lcs/block.rb

@@ -0,0 +1,51 @@
+#! /usr/env/bin ruby
+#--
+# Copyright 2004 Austin Ziegler <diff-lcs@halostatue.ca>
+#   adapted from:
+#     Algorithm::Diff (Perl) by Ned Konz <perl@bike-nomad.com>
+#     Smalltalk by Mario I. Wolczko <mario@wolczko.com>
+#   implements McIlroy-Hunt diff algorithm
+#
+# This program is free software. It may be redistributed and/or modified under
+# the terms of the GPL version 2 (or later), the Perl Artistic licence, or the
+# Ruby licence.
+# 
+# $Id: block.rb,v 1.3 2004/08/08 20:33:09 austin Exp $
+#++
+# Contains Diff::LCS::Block for bin/ldiff.
+
+  # A block is an operation removing, adding, or changing a group of items.
+  # Basically, this is just a list of changes, where each change adds or
+  # deletes a single item. Used by bin/ldiff.
+class Diff::LCS::Block
+  attr_reader :changes, :insert, :remove
+
+  def initialize(chunk)
+    @changes = []
+    @insert = []
+    @remove = []
+
+    chunk.each do |item|
+      @changes << item
+      @remove << item if item.deleting?
+      @insert << item if item.adding?
+    end
+  end
+
+  def diff_size
+    @insert.size - @remove.size
+  end
+
+  def op
+    case [@remove.empty?, @insert.empty?]
+    when [false, false]
+      '!'
+    when [false, true]
+      '-'
+    when [true, false]
+      '+'
+    else # [true, true]
+      '^'
+    end
+  end
+end