| Algorithm::DiffOld(3pm) - phpMan
Algorithm::DiffOld(3pm) User Contributed Perl Documentation 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.
perl v5.14.2 2006-07-31 Algorithm::DiffOld(3pm)
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