bionic (3) Moose::Cookbook::Snack::Types.3pm.gz

NAME

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

VERSION

       version 2.2009

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.