NAME

MOP4Import::Types - fields-aware type builder for inner-type

SYNOPSIS

Create inner-types MyApp::Artist and MyApp::CD using MOP4Import::Types.

            

              
              
# Define subtype Artist and CD with their fields.
package MyApp;
use MOP4Import::Types
  (Artist => [[fields => qw/artistid name/]]
   , CD   => [[fields => qw/cdid artistid title year/]]);
            
          

Above is an equivalent of following:

            

              
              
package MyApp;
sub Artist () {'MyApp::Artist'}
package MyApp::Artist {
   use MOP4Import::Declare [fields => qw/artistid name/];
}
sub CD () {'MyApp::CD'}
package MyApp::CD {
   use MOP4Import::Declare [fields => qw/cdid artistid title year/];
}
            
          

You can use above types like following with compile-time field name typos detection of fields.

            

              
              
sub print_artist_cds {
  (my $self, my Artist $artist) = @_; # $artist is typed.
  my @cds = $self->DB->select(
    CD => {
      artistid => $artist->{artistid}  # Checked statically
    }
  );
  foreach my CD $cd (@cds) { # $cd is typed.
    print tsv($cd->{title}, $cd->{year}), "\n"; # Checked statically
  }
}
            
          

DESCRIPTION

MOP4Import::Types is yet another protocol implementation of MOP4Import family, based on MOP4Import::Pairs and MOP4Import::Declare::Type.

In contrast to MOP4Import::Declare, which is designed to modify target module itself, this module is designed to add new inner-types to target module.

With "inner-type", I mean type declared in some module and not directly exposed as "require" able module.

"MetaObject Protocol for Import" in this module

"import()" method of this module takes name => [@pragma_list] style paired arguments and dispatch them as $myPack->declare_type($opts, $name, @pragma_list).

            

              
              
use MOP4Import::Types
  (Foo => [[fields => qw/bar baz/]]
  , Cat => [[fields => qw/name birth_year/]]
  );
# Above is equivalent of followings
use MOP4Import::Declare::Type [type => Foo => [fields => qw/bar baz/]];
use MOP4Import::Declare::Type [type => Cat => [fields => qw/name birth_year/]];
            
          

Type names can be imported

            

              
              
package MyProject::Types;
use MOP4Import::Types
  (User => [[fields => qw/uid name .../]]
  , Product => [[fields => qw/prodid name .../]]
  , ...
  );
#------------
# You can import above types in other module like following:
#------------
package MyProject::Web;
use MyProject::Types qw/User Product/;
            
          

Extending types in derived class

use MOP4Import::Types::Extend instead.

Specifying base type

use MOP4Import::Types can recognize first HASH argument as option set and you can specify base type via basepkg option.

            

              
              
use MOP4Import::Types +{basepkg => 'YourBaseObject'}
  Foo => [[fields => qw/.../]], ...;
            
          

SEE ALSO

MOP4Import::Declare

AUTHOR

Kobayashi, Hiroaki <hkoba@cpan.org>

LICENSE

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