NAME

       Type::Tie - tie a variable to a type constraint

SYNOPSIS

       Type::Tie is a response to this sort of problem...

          use strict;
          use warnings;

          {
             package Local::Testing;
             use Moose;
             has numbers => ( is => "ro", isa => "ArrayRef[Num]" );
          }

          # Nice list of numbers.
          my @N = ( 1, 2, 3, 3.14159 );

          # Create an object with a reference to that list.
          my $object = Local::Testing->new(numbers => \@N);

          # Everything OK so far...

          # Now watch this!
          push @N, "Monkey!";
          print $object->dump;

          # Houston, we have a problem!

       Just declare @N like this:

          use Type::Tie;
          use Types::Standard qw( Num );

          ttie my @N, Num, ( 1, 2, 3, 3.14159 );

       Now any attempt to add a non-numeric value to @N will die.

DESCRIPTION

       This module exports a single function: "ttie". "ttie" ties a variable to a type
       constraint, ensuring that whatever values stored in the variable will conform to the type
       constraint. If the type constraint has coercions, these will be used if necessary to
       ensure values assigned to the variable conform.

          use Type::Tie;
          use Types::Standard qw( Int Num );

          ttie my $count, Int->plus_coercions(Num, 'int $_'), 0;

          $count++;            # ok
          $count = 2;          # ok
          $count = 3.14159;    # ok, coerced to 3
          $count = "Monkey!";  # dies

       While the examples in documentation (and the test suite) show type constraints from
       Types::Standard, but any type constraint objects supporting the Type::API interfaces
       should work. This includes:

       •   Moose::Meta::TypeConstraint / MooseX::Types

       •   Mouse::Meta::TypeConstraint / MouseX::Types

       •   Specio

       •   Type::Tiny

   About Cloning with Storage::dclone (and Clone::clone)
       Cloning variables with Storage::dclone works, but cloning with Clone::clone is not
       possible. See Bug #127576 for Type-Tie: Doesn't work with Clone::clone
       <https://rt.cpan.org/Public/Bug/Display.html?id=127576>

BUGS

       Please report any bugs to <http://rt.cpan.org/Dist/Display.html?Queue=Type-Tie>.

SUPPORT

       IRC: support is available through in the #moops channel on irc.perl.org
       <http://www.irc.perl.org/channels.html>.

SEE ALSO

       Type::API, Type::Utils, Moose::Manual::Types, MooseX::Lexical::Types.

AUTHOR

       Toby Inkster <tobyink@cpan.org>.

COPYRIGHT AND LICENCE

       This software is copyright (c) 2013-2014, 2018-2019 by Toby Inkster.

       This is free software; you can redistribute it and/or modify it under the same terms as
       the Perl 5 programming language system itself.

DISCLAIMER OF WARRANTIES

       THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
       WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
       PURPOSE.