Moose::Cookbook::SnackUserpContributed Perl DoMoose::Cookbook::Snack::Types(3)NAMEMoose::Cookbook::Snack::Types - Snippets of code for using Types and
Type Constraints
VERSION
version 2.1005
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
AUTHOR
Moose is maintained by the Moose Cabal, along with the help of many
contributors. See "CABAL" in Moose and "CONTRIBUTORS" in Moose for
details.
COPYRIGHT AND LICENSE
This software is copyright (c) 2013 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 v5.18.1 2013-08-07 Moose::Cookbook::Snack::Types(3)
