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

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

NNOOTTEE
       This has been provided as part of the Algorithm::Diff package by Ned
       Konz.  This particular module is OONNLLYY for people who HHAAVVEE 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 traversesequences);

         @lcs    = LCS( \@seq1, \@seq2, $comparisonfunction );

         $lcsref = LCS( \@seq1, \@seq2, $comparisonfunction );

         @diffs = diff( \@seq1, \@seq2, $comparisonfunction );

         traversesequences( \@seq1, \@seq2,
                            { MATCH => $callback,
                              DISCARDA => $callback,
                              DISCARDB => $callback,
                            },
                            $comparisonfunction );

CCOOMMPPAARRIISSOONN FFUUNNCCTTIIOONNSS
       Each of the main routines should be passed a comparison function. If
       you aren't passing one in, uussee AAllggoorriitthhmm::::DDiiffff iinnsstteeaadd.

       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 v5.8.8                       2006-07-30             Algorithm::DiffOld(3)