NAME

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

VERSION

       version 2.1604

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 <stevan.little@iinteractive.com>

       •   Dave Rolsky <autarch@urth.org>

       •   Jesse Luehrs <doy@tozt.net>

       •   Shawn M Moore <code@sartak.org>

       •   יובל קוג'מן (Yuval Kogman) <nothingmuch@woobling.org>

       •   Karen Etheridge <ether@cpan.org>

       •   Florian Ragwitz <rafl@debian.org>

       •   Hans Dieter Pearcey <hdp@weftsoar.net>

       •   Chris Prather <chris@prather.org>

       •   Matt S Trout <mst@shadowcat.co.uk>

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.