Algorithm::DiffOld(3pm)                         User Contributed Perl Documentation                         Algorithm::DiffOld(3pm)

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

       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
       comparisons. 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.

         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 );

       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


         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

       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 v5.32.0                                                 2020-12-17                                     Algorithm::DiffOld(3pm)