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

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.

perl v5.18.2							    2006-07-30						     Algorithm::DiffOld(3)