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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.