1 package Lexical::Types;
10 Lexical::Types - Extend the semantics of typed lexicals.
28 sub TYPEDSCALAR { Some::String::Implementation->new }
33 my Str $x; # $x is now a Some::String::Implementation object
37 This module allows you to hook the execution of typed lexicals declarations (C<my Foo $x>).
38 In particular, it can be used to automatically tie or bless typed lexicals.
40 It is B<not> implemented with a source filter.
46 XSLoader::load(__PACKAGE__, $VERSION);
51 =head2 C<< import [ as => [ $prefix | $mangler ] ] >>
53 Magically called when writing C<use Lexical::Types>.
54 All the occurences of C<my Foo $x> in the current lexical scope will be changed to call at each run a given method in a given package.
55 The method and package are determined by the parameter C<as> :
61 If it's left unspecified, the C<TYPEDSCALAR> method in the C<Foo> package will be called.
64 my Str $x; # calls Str->TYPEDSCALAR
68 If a plain scalar C<$prefix> is passed as the value, the C<TYPEDSCALAR> method in the C<${prefix}::Foo> package will be used.
70 use Lexical::Types as => 'My::'; # or "as => 'My'"
71 my Str $x; # calls My::Str->TYPEDSCALAR
75 If the value given is a code reference C<$mangler>, it will be called at compile-time with arguments C<'Foo'> and C<'TYPEDSCALAR'> and is expected to return the desired package and method name (in that order).
76 If any of those is C<undef>, the default value will be used instead.
78 use Lexical::Types as => sub { 'My', 'new_' . lc($_[0]) };
79 my Str $x; # the coderef indicates to call My->new_str
83 The initializer method receives an alias to the pad entry of C<$x> in C<$_[1]> and the original type name (C<Foo>) in C<$_[2]>.
84 You can either edit C<$_[1]> in place, in which case you should return an empty list, or return a new scalar that will be copied into C<$x>.
94 my $as = delete $args{'as'};
100 $as .= '::' if $as !~ /::$/;
101 $hint = _tag(sub { $as . $_[0] });
103 croak "Invalid $r reference for 'as'";
110 # Yes, we store a coderef inside the hints hash, but that's just for compile
112 $^H{+(__PACKAGE__)} = $hint;
117 Magically called when writing C<no Lexical::Types>.
118 Turns the module off.
123 $^H{+(__PACKAGE__)} = undef;
128 You can integrate L<Lexical::Types> in your module so that using it will provide types to your users without asking them to load either L<Lexical::Types> or the type classes manually.
132 BEGIN { require Lexical::Types; }
135 eval 'package Str; package Int'; # The types you want to support
136 Lexical::Types->import(
137 as => sub { __PACKAGE__, 'new_' . lc($_[0]) }
142 Lexical::Types->unimport;
151 For C<perl> to be able to parse C<my Foo $x>, the package C<Foo> must be defined somewhere, and this even if you use the C<as> option to redirect to another package.
152 It's unlikely to find a workaround, as this happens deep inside the lexer, far from the reach of an extension.
154 Only one mangler or prefix can be in use at the same time in a given scope.
158 L<perl> 5.8, L<XSLoader>.
164 L<Attribute::Handlers>.
168 Vincent Pit, C<< <perl at profvince.com> >>, L<http://www.profvince.com>.
170 You can contact me by mail or on C<irc.perl.org> (vincent).
174 Please report any bugs or feature requests to C<bug-lexical-types at rt.cpan.org>, or through the web interface at L<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Lexical-Types>. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.
178 You can find documentation for this module with the perldoc command.
180 perldoc Lexical::Types
182 =head1 ACKNOWLEDGEMENTS
184 Inspired by Ricardo Signes.
186 =head1 COPYRIGHT & LICENSE
188 Copyright 2009 Vincent Pit, all rights reserved.
190 This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
194 1; # End of Lexical::Types