package Lexical::Types;
+use 5.008;
+
use strict;
use warnings;
=head1 VERSION
-Version 0.01
+Version 0.02
=cut
our $VERSION;
BEGIN {
- $VERSION = '0.01';
+ $VERSION = '0.02';
}
=head1 SYNOPSIS
=head1 DESCRIPTION
-This module allows you to hook the execution of typed lexicals declarations (C<my Foo $x>).
+This module allows you to hook the execution of typed lexicals declarations (C<my Str $x>).
In particular, it can be used to automatically tie or bless typed lexicals.
It is B<not> implemented with a source filter.
=head2 C<< import [ as => [ $prefix | $mangler ] ] >>
Magically called when writing C<use Lexical::Types>.
-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.
-The method and package are determined by the parameter C<as> :
+All the occurences of C<my Str $x> in the current lexical scope will be changed to call at each run a given method in a given package.
+The method and package are determined by the parameter C<'as'> :
=over 4
=item *
-If it's left unspecified, the C<TYPEDSCALAR> method in the C<Foo> package will be called.
+If it's left unspecified, the C<TYPEDSCALAR> method in the C<Str> package will be called.
use Lexical::Types;
my Str $x; # calls Str->TYPEDSCALAR
=item *
-If a plain scalar C<$prefix> is passed as the value, the C<TYPEDSCALAR> method in the C<${prefix}::Foo> package will be used.
+If a plain scalar C<$prefix> is passed as the value, the C<TYPEDSCALAR> method in the C<${prefix}::Str> package will be used.
use Lexical::Types as => 'My::'; # or "as => 'My'"
my Str $x; # calls My::Str->TYPEDSCALAR
=item *
-If the value given is a code reference C<$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).
-If any of those is C<undef>, the default value will be used instead.
+If the value given is a code reference C<$mangler>, it will be called at compile-time with arguments C<'Str'> and C<'TYPEDSCALAR'> and is expected to return :
+
+=over 4
+
+=item *
+
+either an empty list, in which case the current typed lexical definition will be skipped (thus it won't be altered to trigger a run-time hook) ;
+
+ use Lexical::Types as => sub { return $_[0] =~ /Str/ ? () : @_ };
+ my Str $x; # nothing special
+ my Int $y; # calls Int->TYPEDSCALAR
+
+=item *
+
+or the desired package and method name, in that order (if any of those is C<undef>, the default value will be used instead).
use Lexical::Types as => sub { 'My', 'new_' . lc($_[0]) };
my Str $x; # the coderef indicates to call My->new_str
=back
-The initializer method receives an alias to the pad entry of C<$x> in C<$_[1]> and the original type name (C<Foo>) in C<$_[2]>.
+=back
+
+The initializer method receives an alias to the pad entry of C<$x> in C<$_[1]> and the original type name (C<Str>) in C<$_[2]>.
You can either edit C<$_[1]> in place, in which case you should return an empty list, or return a new scalar that will be copied into C<$x>.
=cut
=head1 CAVEATS
-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.
-It's unlikely to find a workaround, as this happens deep inside the lexer, far from the reach of an extension.
+For C<perl> to be able to parse C<my Str $x>, you need :
+
+=over 4
+
+=item *
+
+either the C<Str> package to be defined ;
+
+=item *
+
+or for C<Str> to be a constant sub returning a valid defined package.
+
+=back
+
+Those restrictions apply even if you use the C<'as'> option to redirect to another package, and are unlikely to find a workaround as this happens deep inside the lexer - far from the reach of an extension.
Only one mangler or prefix can be in use at the same time in a given scope.
perldoc Lexical::Types
+Tests code coverage report is available at L<http://www.profvince.com/perl/cover/Lexical-Types>.
+
=head1 ACKNOWLEDGEMENTS
Inspired by Ricardo Signes.
+Thanks Florian Ragwitz for suggesting the use of constants for types.
+
=head1 COPYRIGHT & LICENSE
Copyright 2009 Vincent Pit, all rights reserved.