323 lines
11 KiB
Ruby
323 lines
11 KiB
Ruby
#! /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: callbacks.rb,v 1.4 2004/09/14 18:51:26 austin Exp $
|
|
#++
|
|
# Contains definitions for all default callback objects.
|
|
|
|
require 'diff/lcs/change'
|
|
|
|
module Diff::LCS
|
|
# This callback object implements the default set of callback events, which
|
|
# only returns the event itself. Note that #finished_a and #finished_b are
|
|
# not implemented -- I haven't yet figured out where they would be useful.
|
|
#
|
|
# Note that this is intended to be called as is, e.g.,
|
|
#
|
|
# Diff::LCS.LCS(seq1, seq2, Diff::LCS::DefaultCallbacks)
|
|
class DefaultCallbacks
|
|
class << self
|
|
# Called when two items match.
|
|
def match(event)
|
|
event
|
|
end
|
|
# Called when the old value is discarded in favour of the new value.
|
|
def discard_a(event)
|
|
event
|
|
end
|
|
# Called when the new value is discarded in favour of the old value.
|
|
def discard_b(event)
|
|
event
|
|
end
|
|
# Called when both the old and new values have changed.
|
|
def change(event)
|
|
event
|
|
end
|
|
|
|
private :new
|
|
end
|
|
end
|
|
|
|
# An alias for DefaultCallbacks that is used in Diff::LCS#traverse_sequences.
|
|
#
|
|
# Diff::LCS.LCS(seq1, seq2, Diff::LCS::SequenceCallbacks)
|
|
SequenceCallbacks = DefaultCallbacks
|
|
# An alias for DefaultCallbacks that is used in Diff::LCS#traverse_balanced.
|
|
#
|
|
# Diff::LCS.LCS(seq1, seq2, Diff::LCS::BalancedCallbacks)
|
|
BalancedCallbacks = DefaultCallbacks
|
|
end
|
|
|
|
# This will produce a compound array of simple diff change objects. Each
|
|
# element in the #diffs array is a +hunk+ or +hunk+ array, where each
|
|
# element in each +hunk+ array is a single Change object representing the
|
|
# addition or removal of a single element from one of the two tested
|
|
# sequences. The +hunk+ provides the full context for the changes.
|
|
#
|
|
# diffs = Diff::LCS.diff(seq1, seq2)
|
|
# # This example shows a simplified array format.
|
|
# # [ [ [ '-', 0, 'a' ] ], # 1
|
|
# # [ [ '+', 2, 'd' ] ], # 2
|
|
# # [ [ '-', 4, 'h' ], # 3
|
|
# # [ '+', 4, 'f' ] ],
|
|
# # [ [ '+', 6, 'k' ] ], # 4
|
|
# # [ [ '-', 8, 'n' ], # 5
|
|
# # [ '-', 9, 'p' ],
|
|
# # [ '+', 9, 'r' ],
|
|
# # [ '+', 10, 's' ],
|
|
# # [ '+', 11, 't' ] ] ]
|
|
#
|
|
# There are five hunks here. The first hunk says that the +a+ at position 0
|
|
# of the first sequence should be deleted (<tt>'-'</tt>). The second hunk
|
|
# says that the +d+ at position 2 of the second sequence should be inserted
|
|
# (<tt>'+'</tt>). The third hunk says that the +h+ at position 4 of the
|
|
# first sequence should be removed and replaced with the +f+ from position 4
|
|
# of the second sequence. The other two hunks are described similarly.
|
|
#
|
|
# === Use
|
|
# This callback object must be initialised and is used by the Diff::LCS#diff
|
|
# method.
|
|
#
|
|
# cbo = Diff::LCS::DiffCallbacks.new
|
|
# Diff::LCS.LCS(seq1, seq2, cbo)
|
|
# cbo.finish
|
|
#
|
|
# Note that the call to #finish is absolutely necessary, or the last set of
|
|
# changes will not be visible. Alternatively, can be used as:
|
|
#
|
|
# cbo = Diff::LCS::DiffCallbacks.new { |tcbo| Diff::LCS.LCS(seq1, seq2, tcbo) }
|
|
#
|
|
# The necessary #finish call will be made.
|
|
#
|
|
# === Simplified Array Format
|
|
# The simplified array format used in the example above can be obtained
|
|
# with:
|
|
#
|
|
# require 'pp'
|
|
# pp diffs.map { |e| e.map { |f| f.to_a } }
|
|
class Diff::LCS::DiffCallbacks
|
|
# Returns the difference set collected during the diff process.
|
|
attr_reader :diffs
|
|
|
|
def initialize # :yields self:
|
|
@hunk = []
|
|
@diffs = []
|
|
|
|
if block_given?
|
|
begin
|
|
yield self
|
|
ensure
|
|
self.finish
|
|
end
|
|
end
|
|
end
|
|
|
|
# Finalizes the diff process. If an unprocessed hunk still exists, then it
|
|
# is appended to the diff list.
|
|
def finish
|
|
add_nonempty_hunk
|
|
end
|
|
|
|
def match(event)
|
|
add_nonempty_hunk
|
|
end
|
|
|
|
def discard_a(event)
|
|
@hunk << Diff::LCS::Change.new('-', event.old_position, event.old_element)
|
|
end
|
|
|
|
def discard_b(event)
|
|
@hunk << Diff::LCS::Change.new('+', event.new_position, event.new_element)
|
|
end
|
|
|
|
private
|
|
def add_nonempty_hunk
|
|
@diffs << @hunk unless @hunk.empty?
|
|
@hunk = []
|
|
end
|
|
end
|
|
|
|
# This will produce a compound array of contextual diff change objects. Each
|
|
# element in the #diffs array is a "hunk" array, where each element in each
|
|
# "hunk" array is a single change. Each change is a Diff::LCS::ContextChange
|
|
# that contains both the old index and new index values for the change. The
|
|
# "hunk" provides the full context for the changes. Both old and new objects
|
|
# will be presented for changed objects. +nil+ will be substituted for a
|
|
# discarded object.
|
|
#
|
|
# 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)
|
|
#
|
|
# diffs = Diff::LCS.diff(seq1, seq2, Diff::LCS::ContextDiffCallbacks)
|
|
# # This example shows a simplified array format.
|
|
# # [ [ [ '-', [ 0, 'a' ], [ 0, nil ] ] ], # 1
|
|
# # [ [ '+', [ 3, nil ], [ 2, 'd' ] ] ], # 2
|
|
# # [ [ '-', [ 4, 'h' ], [ 4, nil ] ], # 3
|
|
# # [ '+', [ 5, nil ], [ 4, 'f' ] ] ],
|
|
# # [ [ '+', [ 6, nil ], [ 6, 'k' ] ] ], # 4
|
|
# # [ [ '-', [ 8, 'n' ], [ 9, nil ] ], # 5
|
|
# # [ '+', [ 9, nil ], [ 9, 'r' ] ],
|
|
# # [ '-', [ 9, 'p' ], [ 10, nil ] ],
|
|
# # [ '+', [ 10, nil ], [ 10, 's' ] ],
|
|
# # [ '+', [ 10, nil ], [ 11, 't' ] ] ] ]
|
|
#
|
|
# The five hunks shown are comprised of individual changes; if there is a
|
|
# related set of changes, they are still shown individually.
|
|
#
|
|
# This callback can also be used with Diff::LCS#sdiff, which will produce
|
|
# results like:
|
|
#
|
|
# diffs = Diff::LCS.sdiff(seq1, seq2, Diff::LCS::ContextCallbacks)
|
|
# # This example shows a simplified array format.
|
|
# # [ [ [ "-", [ 0, "a" ], [ 0, nil ] ] ], # 1
|
|
# # [ [ "+", [ 3, nil ], [ 2, "d" ] ] ], # 2
|
|
# # [ [ "!", [ 4, "h" ], [ 4, "f" ] ] ], # 3
|
|
# # [ [ "+", [ 6, nil ], [ 6, "k" ] ] ], # 4
|
|
# # [ [ "!", [ 8, "n" ], [ 9, "r" ] ], # 5
|
|
# # [ "!", [ 9, "p" ], [ 10, "s" ] ],
|
|
# # [ "+", [ 10, nil ], [ 11, "t" ] ] ] ]
|
|
#
|
|
# The five hunks are still present, but are significantly shorter in total
|
|
# presentation, because changed items are shown as changes ("!") instead of
|
|
# potentially "mismatched" pairs of additions and deletions.
|
|
#
|
|
# The result of this operation is similar to that of
|
|
# Diff::LCS::SDiffCallbacks. They may be compared as:
|
|
#
|
|
# s = Diff::LCS.sdiff(seq1, seq2).reject { |e| e.action == "=" }
|
|
# c = Diff::LCS.sdiff(seq1, seq2, Diff::LCS::ContextDiffCallbacks).flatten
|
|
#
|
|
# s == c # -> true
|
|
#
|
|
# === Use
|
|
# This callback object must be initialised and can be used by the
|
|
# Diff::LCS#diff or Diff::LCS#sdiff methods.
|
|
#
|
|
# cbo = Diff::LCS::ContextDiffCallbacks.new
|
|
# Diff::LCS.LCS(seq1, seq2, cbo)
|
|
# cbo.finish
|
|
#
|
|
# Note that the call to #finish is absolutely necessary, or the last set of
|
|
# changes will not be visible. Alternatively, can be used as:
|
|
#
|
|
# cbo = Diff::LCS::ContextDiffCallbacks.new { |tcbo| Diff::LCS.LCS(seq1, seq2, tcbo) }
|
|
#
|
|
# The necessary #finish call will be made.
|
|
#
|
|
# === Simplified Array Format
|
|
# The simplified array format used in the example above can be obtained
|
|
# with:
|
|
#
|
|
# require 'pp'
|
|
# pp diffs.map { |e| e.map { |f| f.to_a } }
|
|
class Diff::LCS::ContextDiffCallbacks < Diff::LCS::DiffCallbacks
|
|
def discard_a(event)
|
|
@hunk << Diff::LCS::ContextChange.simplify(event)
|
|
end
|
|
|
|
def discard_b(event)
|
|
@hunk << Diff::LCS::ContextChange.simplify(event)
|
|
end
|
|
|
|
def change(event)
|
|
@hunk << Diff::LCS::ContextChange.simplify(event)
|
|
end
|
|
end
|
|
|
|
# This will produce a simple array of diff change objects. Each element in
|
|
# the #diffs array is a single ContextChange. In the set of #diffs provided
|
|
# by SDiffCallbacks, both old and new objects will be presented for both
|
|
# changed <strong>and unchanged</strong> objects. +nil+ will be substituted
|
|
# for a discarded object.
|
|
#
|
|
# The diffset produced by this callback, when provided to Diff::LCS#sdiff,
|
|
# will compute and display the necessary components to show two sequences
|
|
# and their minimized differences side by side, just like the Unix utility
|
|
# +sdiff+.
|
|
#
|
|
# same same
|
|
# before | after
|
|
# old < -
|
|
# - > new
|
|
#
|
|
# 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)
|
|
#
|
|
# diffs = Diff::LCS.sdiff(seq1, seq2)
|
|
# # This example shows a simplified array format.
|
|
# # [ [ "-", [ 0, "a"], [ 0, nil ] ],
|
|
# # [ "=", [ 1, "b"], [ 0, "b" ] ],
|
|
# # [ "=", [ 2, "c"], [ 1, "c" ] ],
|
|
# # [ "+", [ 3, nil], [ 2, "d" ] ],
|
|
# # [ "=", [ 3, "e"], [ 3, "e" ] ],
|
|
# # [ "!", [ 4, "h"], [ 4, "f" ] ],
|
|
# # [ "=", [ 5, "j"], [ 5, "j" ] ],
|
|
# # [ "+", [ 6, nil], [ 6, "k" ] ],
|
|
# # [ "=", [ 6, "l"], [ 7, "l" ] ],
|
|
# # [ "=", [ 7, "m"], [ 8, "m" ] ],
|
|
# # [ "!", [ 8, "n"], [ 9, "r" ] ],
|
|
# # [ "!", [ 9, "p"], [ 10, "s" ] ],
|
|
# # [ "+", [ 10, nil], [ 11, "t" ] ] ]
|
|
#
|
|
# The result of this operation is similar to that of
|
|
# Diff::LCS::ContextDiffCallbacks. They may be compared as:
|
|
#
|
|
# s = Diff::LCS.sdiff(seq1, seq2).reject { |e| e.action == "=" }
|
|
# c = Diff::LCS.sdiff(seq1, seq2, Diff::LCS::ContextDiffCallbacks).flatten
|
|
#
|
|
# s == c # -> true
|
|
#
|
|
# === Use
|
|
# This callback object must be initialised and is used by the Diff::LCS#sdiff
|
|
# method.
|
|
#
|
|
# cbo = Diff::LCS::SDiffCallbacks.new
|
|
# Diff::LCS.LCS(seq1, seq2, cbo)
|
|
#
|
|
# As with the other initialisable callback objects, Diff::LCS::SDiffCallbacks
|
|
# can be initialised with a block. As there is no "fininishing" to be done,
|
|
# this has no effect on the state of the object.
|
|
#
|
|
# cbo = Diff::LCS::SDiffCallbacks.new { |tcbo| Diff::LCS.LCS(seq1, seq2, tcbo) }
|
|
#
|
|
# === Simplified Array Format
|
|
# The simplified array format used in the example above can be obtained
|
|
# with:
|
|
#
|
|
# require 'pp'
|
|
# pp diffs.map { |e| e.to_a }
|
|
class Diff::LCS::SDiffCallbacks
|
|
# Returns the difference set collected during the diff process.
|
|
attr_reader :diffs
|
|
|
|
def initialize #:yields self:
|
|
@diffs = []
|
|
yield self if block_given?
|
|
end
|
|
|
|
def match(event)
|
|
@diffs << Diff::LCS::ContextChange.simplify(event)
|
|
end
|
|
|
|
def discard_a(event)
|
|
@diffs << Diff::LCS::ContextChange.simplify(event)
|
|
end
|
|
|
|
def discard_b(event)
|
|
@diffs << Diff::LCS::ContextChange.simplify(event)
|
|
end
|
|
|
|
def change(event)
|
|
@diffs << Diff::LCS::ContextChange.simplify(event)
|
|
end
|
|
end
|