From: Austin Ziegler Date: 2004-08-09T06:25:26+09:00 Subject: [ANN] Diff::LCS 1.1.0, Diff::LCS 1.0.4 It is with pleasure that I announce the latest versions of Diff::LCS, a pure-Ruby differencing algorithm. Version 1.0.4 is an incremental bugfix that improves the installer (it is not entirely fixed for ri document generation; I believe that I have done most of what I can do with this), fixes a problem of missing left-side changes when comparing against an empty sequence, and fixes a problem with ldiff output, especially for unified diff output. Version 1.1.0 is a feature release that includes all bugfixes up to and including 1.0.4. In addition, it adds a new standard callback (ContextDiffCallback) that works similarly to SDiffCallback but produces a smaller diff set. More importantly, it is now possible to patch a sequence with a diff set to produce the second sequence. If the patch is performed without specifying direction, then it will be examined to see which direction in which the patch will be performed. If the patch is performed by specifying the direction, then the patch will be performed without verification that the patch set applies to the source sequence. Using version 1.0.4, I have produced a couple of patches today for both rdoc and for Ruby's dir.c that look *exactly* like they do from unix diff (at least the version included with cygwin). Both versions can be found in the Ruwiki project filelist: http://rubyforge.org/frs/?group_id=84 -austin Diff::LCS README ================ Diff::LCS is a port of Algorithm::Diff[1] that uses the McIlroy-Hunt longest common subsequence (LCS) algorithm to compute intelligent differences between two sequenced enumerable containers[2]. The implementation is based on Mario I. Wolczko's[3] Smalltalk version (1.2, 1993)[4] and Ned Konz's[5] Perl version (Algorithm::Diff)[6]. This release is version 1.1.0 with the addition of new features, including the ability to #patch and #unpatch changes as well as a new contextual diff callback, Diff::LCS::ContextDiffCallbacks, that should improve the context sensitivity of patching. Using this module is quite simple. By default, Diff::LCS does not extend objects with the Diff::LCS interface, but will be called as if it were a function: require 'diff/lcs' seq1 = %w(a b c e h j l m n p) seq2 = %w(b c d e f j k l m r s t) lcs = Diff::LCS.LCS(seq1, seq2) diffs = Diff::LCS.diff(seq1, seq2) sdiff = Diff::LCS.sdiff(seq1, seq2) seq = Diff::LCS.traverse_sequences(seq1, seq2, callback_obj) bal = Diff::LCS.traverse_balanced(seq1, seq2, callback_obj) seq2 == Diff::LCS.patch!(seq1, diffs) seq1 == Diff::LCS.unpatch!(seq2, diffs) seq2 == Diff::LCS.patch!(seq1, sdiff) seq1 == Diff::LCS.unpatch!(seq2, sdiff) Objects can be extended with Diff::LCS: seq1.extend(Diff::LCS) lcs = seq1.lcs(seq2) diffs = seq1.diff(seq2) sdiff = seq1.sdiff(seq2) seq = seq1.traverse_sequences(seq2, callback_obj) bal = seq1.traverse_balanced(seq2, callback_obj) seq2 == seq1.patch!(diffs) seq1 == seq2.unpatch!(diffs) seq2 == seq1.patch!(sdiff) seq1 == seq2.unpatch!(sdiff) By requiring 'diff/lcs/array' or 'diff/lcs/string', Array or String will be extended for use this way. Copyright ========= # Copyright 2004 Austin Ziegler # adapted from: # Algorithm::Diff (Perl) by Ned Konz # Smalltalk by Mario I. Wolczko # 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: README,v 1.5 2004/08/08 20:33:09 austin Exp $ Footnotes ========= [1] This library is called Diff::LCS because there are multiple Ruby libraries called Algorithm::Diff maintained by other authors. [2] By sequenced enumerable, I mean that the order of enumeration is predictable and consistent for the same set of data. While it is theoretically possible to generate a diff for unordereded hash, it will only be meaningful if the enumeration of the hashes is consistent. In general, this will mean that containers that behave like String or Array will perform best. [3] mario@wolczko.com [4] ftp://st.cs.uiuc.edu/pub/Smalltalk/MANCHESTER/manchester/4.0/diff.st [5] perl@bike-nomad.com [6] http://search.cpan.org/~nedkonz/Algorithm-Diff-1.15/ -- Austin Ziegler * halostatue@gmail.com * Alternate: austin@halostatue.ca