1Algorithm::DiffOld(3) User Contributed Perl DocumentationAlgorithm::DiffOld(3)
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NAME

6       Algorithm::DiffOld - Compute `intelligent' differences between two
7       files / lists but use the old (<=0.59) interface.
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NOTE

10       This has been provided as part of the Algorithm::Diff package by Ned
11       Konz.  This particular module is ONLY for people who HAVE to have the
12       old interface, which uses a comparison function rather than a key
13       generating function.
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15       Because each of the lines in one array have to be compared with each of
16       the lines in the other array, this does M*N comparisons. This can be
17       very slow. I clocked it at taking 18 times as long as the stock version
18       of Algorithm::Diff for a 4000-line file. It will get worse
19       quadratically as array sizes increase.
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SYNOPSIS

22         use Algorithm::DiffOld qw(diff LCS traverse_sequences);
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24         @lcs    = LCS( \@seq1, \@seq2, $comparison_function );
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26         $lcsref = LCS( \@seq1, \@seq2, $comparison_function );
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28         @diffs = diff( \@seq1, \@seq2, $comparison_function );
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30         traverse_sequences( \@seq1, \@seq2,
31                            { MATCH => $callback,
32                              DISCARD_A => $callback,
33                              DISCARD_B => $callback,
34                            },
35                            $comparison_function );
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COMPARISON FUNCTIONS

38       Each of the main routines should be passed a comparison function. If
39       you aren't passing one in, use Algorithm::Diff instead.
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41       These functions should return a true value when two items should
42       compare as equal.
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44       For instance,
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46         @lcs    = LCS( \@seq1, \@seq2, sub { my ($a, $b) = @_; $a eq $b } );
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48       but if that is all you're doing with your comparison function, just use
49       Algorithm::Diff and let it do this (this is its default).
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51       Or:
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53         sub someFunkyComparisonFunction
54         {
55               my ($a, $b) = @_;
56               $a =~ m{$b};
57         }
58
59         @diffs = diff( \@lines, \@patterns, \&someFunkyComparisonFunction );
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61       which would allow you to diff an array @lines which consists of text
62       lines with an array @patterns which consists of regular expressions.
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64       This is actually the reason I wrote this version -- there is no way to
65       do this with a key generation function as in the stock Algorithm::Diff.
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69perl v5.36.0                      2023-01-19             Algorithm::DiffOld(3)
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