Data::Compare - compare perl data structures
use Data::Compare; my $h1 = { 'foo' => [ 'bar', 'baz' ], 'FOO' => [ 'one', 'two' ] }; my $h2 = { 'foo' => [ 'bar', 'barf' ], 'FOO' => [ 'one', 'two' ] }; my @a1 = ('one', 'two'); my @a2 = ('bar', 'baz'); my %v = ( 'FOO', \@a1, 'foo', \@a2 ); # simple procedural interface print 'structures of $h1 and \%v are ', Compare($h1, \%v) ? "" : "not ", "identical.\n"; print 'structures of $h1 and $h2 are ', Compare($h1, $h2, { ignore_hash_keys => [qw(foo)] }) ? '' : 'not ', "close enough to identical.\n"; # OO usage my $c = new Data::Compare($h1, \%v); print 'structures of $h1 and \%v are ', $c->Cmp ? "" : "not ", "identical.\n"; # or my $c = new Data::Compare; print 'structures of $h and \%v are ', $c->Cmp($h1, \%v) ? "" : "not ", "identical.\n";
Compare two perl data structures recursively. Returns 0 if the structures differ, else returns 1.
A few data types are treated as special cases:
This has been moved into a plugin, although functionality remains the same as with the previous version. Full documentation is in Data::Compare::Plugins::Scalar::Properties.
These are stringified before comparison, so the following will match:
$r = qr/abc/i; $s = qr/abc/i; Compare($r, $s);
and the following won't, despite them matching *exactly* the same text:
$r = qr/abc/i; $s = qr/[aA][bB][cC]/; Compare($r, $s);
Sorry, that's the best we can do.
These are assumed not to match unless the references are identical - ie, both are references to the same thing.
You may also customise how we compare structures by supplying options in a hashref as a third parameter to the Compare() function. This is not yet available through the OO-ish interface. These options will be in force for the *whole* of your comparison, so will apply to structures that are lurking deep down in your data as well as at the top level, so beware!
Compare()
an arrayref of strings. When comparing two hashes, any keys mentioned in this list will be ignored.
Comparing a circular structure to itself returns true:
$x = \$y; $y = \$x; Compare([$x, $y], [$x, $y]);
But comparing two different circular structures returns false:
$x = \$y; $y = \$x; Compare([$x, $y], [$y, $x]); # <-- note different order
And on a sort-of-related note, if you try to compare insanely deeply nested structures, the module will spit a warning. For this to affect you, you need to go around a hundred levels deep though, and if you do that you have bigger problems which I can't help you with ;-)
The module takes plug-ins so you can provide specialised routines for comparing your own objects and data-types. For details see Data::Compare::Plugins.
Plugins are *not* available when running in "taint" mode.
A couple of functions are provided to examine what goodies have been made available through plugins:
Returns a structure (a hash ref) describing all the comparisons made available through plugins. This function is *not* exported, so should be called as Data::Compare::plugins(). It takes no parameters.
Returns formatted text
Plugin support is not quite finished (see the TODO file for details) but is usable. The missing bits are bells and whistles rather than core functionality.
Fabien Tassin fta@sofaraway.org
Copyright (c) 1999-2001 Fabien Tassin. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
Seeing that Fabien seems to have disappeared, David Cantrell has become a co-maintainer so he can apply needed patches. The licence, of course, remains the same, and all communications about this module should be CCed to Fabien in case he ever returns and wants his baby back.
Portions, including plugins, copyright 2003-2004 David Cantrell david@cantrell.org.uk
perl(1), perlref(1)
To install Data::Compare, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Data::Compare
CPAN shell
perl -MCPAN -e shell install Data::Compare
For more information on module installation, please visit the detailed CPAN module installation guide.