Moose::Cookbook::Snack::Types(3User Contributed Perl DocumentatMoose::Cookbook::Snack::Types(3pm)
NAME
Moose::Cookbook::Snack::Types - Snippets of code for using Types and Type Constraints
VERSION
version 2.2200
SYNOPSIS
package Point;
use Moose;
has 'x' => ( isa => 'Int', is => 'ro' );
has 'y' => ( isa => 'Int', is => 'rw' );
package main;
use Try::Tiny;
my $point = try {
Point->new( x => 'fifty', y => 'forty' );
}
catch {
print "Oops: $_";
};
my $point;
my $xval = 'forty-two';
my $xattribute = Point->meta->find_attribute_by_name('x');
my $xtype_constraint = $xattribute->type_constraint;
if ( $xtype_constraint->check($xval) ) {
$point = Point->new( x => $xval, y => 0 );
}
else {
print "Value: $xval is not an " . $xtype_constraint->name . "\n";
}
DESCRIPTION
This is the Point example from Moose::Cookbook::Basics::Point_AttributesAndSubclassing
with type checking added.
If we try to assign a string value to an attribute that is an "Int", Moose will die with
an explicit error message. The error will include the attribute name, as well as the type
constraint name and the value which failed the constraint check.
We use Try::Tiny to catch this error message.
Later, we get the Moose::Meta::TypeConstraint object from a Moose::Meta::Attribute and use
the Moose::Meta::TypeConstraint to check a value directly.
SEE ALSO
Moose::Cookbook::Basics::Point_AttributesAndSubclassing
Moose::Util::TypeConstraints
Moose::Meta::Attribute
AUTHORS
o Stevan Little <stevan AT cpan.org>
o Dave Rolsky <autarch AT urth.org>
o Jesse Luehrs <doy AT cpan.org>
o Shawn M Moore <sartak AT cpan.org>
o ' (Yuval Kogman) <nothingmuch AT woobling.org>
o Karen Etheridge <ether AT cpan.org>
o Florian Ragwitz <rafl AT debian.org>
o Hans Dieter Pearcey <hdp AT cpan.org>
o Chris Prather <chris AT prather.org>
o Matt S Trout <mstrout AT cpan.org>
COPYRIGHT AND LICENSE
This software is copyright (c) 2006 by Infinity Interactive, Inc.
This is free software; you can redistribute it and/or modify it under the same terms as
the Perl 5 programming language system itself.
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