Data::Compare - compare perl data structures |
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:
$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.
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!
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 the Data::Compare::Plugins manpage.
Plugins are *not* available when running in ``taint'' mode. You may
also make it not load plugins by providing an empty list as the
argument to import()
- ie, by doing this:
use Data::Compare ();
A couple of functions are provided to examine what goodies have been made available through plugins:
For historical reasons, the Compare()
function is exported. If you
don't want this, then pass an empty list to import()
as explained
under PLUGINS. If you want no export but do want plugins, then pass
the empty list, and then call the register_plugins class method:
use Data::Compare (); Data::Compare->register_plugins;
or you could call it as a function if that floats your boat.
http://drhyde.cvs.sourceforge.net/drhyde/perlmodules/Data-Compare/
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.
Plugins are unavailable if you can't change to the current directory. This might happen if you started your process as a priveleged user and then dropped priveleges. This is due to how we check for Taintedness. If this affects you, please supply a portable patch.
Fabien Tassin <fta@sofaraway.org>
Portions by David Cantrell <david@cantrell.org.uk>
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.
Some parts copyright 2003 - 2008 David Cantrell.
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.
perl(1), perlref(1)
Data::Compare - compare perl data structures |