Moose::Cookbook::Snack::Types - Snippets of code for using Types and Type Constraints

NAME  VERSION  SYNOPSIS  DESCRIPTION  SEE ALSO  AUTHORS  COPYRIGHT AND LICENSE 

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NAME

Moose::Cookbook::Snack::Types − Snippets of code for using Types and Type Constraints

VERSION

version 2.2206

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

	•		Stevan Little <[email protected]>
	•		Dave Rolsky <[email protected]>
	•		Jesse Luehrs <[email protected]>
	•		Shawn M Moore <[email protected]>
	•		×××× ×§××’×× (Yuval Kogman) <[email protected]>
	•		Karen Etheridge <[email protected]>
	•		Florian Ragwitz <[email protected]>
	•		Hans Dieter Pearcey <[email protected]>
	•		Chris Prather <[email protected]>
	•		Matt S Trout <[email protected]>

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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