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Perceptual Image Diff 1.0.2 (Default branch)
07-10-2008
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Algorithm::DiffOld(3pm) User Contributed Perl Documentation Algorithm::DiffOld(3pm) NAME
Algorithm::DiffOld - Compute `intelligent' differences between two files / lists but use the old (<=0.59) interface. NOTE
This has been provided as part of the Algorithm::Diff package by Ned Konz. This particular module is ONLY for people who HAVE to have the old interface, which uses a comparison function rather than a key generating function. Because each of the lines in one array have to be compared with each of the lines in the other array, this does M*N comparisions. This can be very slow. I clocked it at taking 18 times as long as the stock version of Algorithm::Diff for a 4000-line file. It will get worse quadratically as array sizes increase. SYNOPSIS
use Algorithm::DiffOld qw(diff LCS traverse_sequences); @lcs = LCS( @seq1, @seq2, $comparison_function ); $lcsref = LCS( @seq1, @seq2, $comparison_function ); @diffs = diff( @seq1, @seq2, $comparison_function ); traverse_sequences( @seq1, @seq2, { MATCH => $callback, DISCARD_A => $callback, DISCARD_B => $callback, }, $comparison_function ); COMPARISON FUNCTIONS
Each of the main routines should be passed a comparison function. If you aren't passing one in, use Algorithm::Diff instead. These functions should return a true value when two items should compare as equal. For instance, @lcs = LCS( @seq1, @seq2, sub { my ($a, $b) = @_; $a eq $b } ); but if that is all you're doing with your comparison function, just use Algorithm::Diff and let it do this (this is its default). Or: sub someFunkyComparisonFunction { my ($a, $b) = @_; $a =~ m{$b}; } @diffs = diff( @lines, @patterns, &someFunkyComparisonFunction ); which would allow you to diff an array @lines which consists of text lines with an array @patterns which consists of regular expressions. This is actually the reason I wrote this version -- there is no way to do this with a key generation function as in the stock Algorithm::Diff. perl v5.10.1 2006-07-31 Algorithm::DiffOld(3pm)