Moose::Cookbook::SnackUserpContributed Perl DoMoose::Cookbook::Snack::Types(3)NAME
Moose::Cookbook::Snack::Types - Snippets of code for using Types and
Type Constraints
VERSION
version 2.0205
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::Recipe1 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::Recipe1
Moose::Utils::TypeConstraints
Moose::Meta::Attribute
AUTHOR
Stevan Little <stevan@iinteractive.com>
COPYRIGHT AND LICENSE
This software is copyright (c) 2011 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.
perl v5.12.5 2011-09-06 Moose::Cookbook::Snack::Types(3)