Provided by: libalgorithm-diff-perl_1.19.03-2_all bug


       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 default).


         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.