1 package Moose::Exporter;
6 use Carp qw( confess );
8 use List::MoreUtils qw( first_index uniq );
14 sub build_import_methods {
18 my $exporting_package = caller();
20 $EXPORT_SPEC{$exporting_package} = \%args;
22 my @exports_from = $class->_follow_also( $exporting_package );
25 = $class->_make_sub_exporter_params( $exporting_package, @exports_from );
27 my $exporter = Sub::Exporter::build_exporter(
30 groups => { default => [':all'] }
34 # $args{_export_to_main} exists for backwards compat, because
35 # Moose::Util::TypeConstraints did export to main (unlike Moose &
37 my $import = $class->_make_import_sub( $exporter, \@exports_from, $args{_export_to_main} );
39 my $unimport = $class->_make_unimport_sub( \@exports_from, [ keys %{$exports} ] );
42 *{ $exporting_package . '::import' } = $import;
43 *{ $exporting_package . '::unimport' } = $unimport;
51 my $exporting_package = shift;
53 %seen = ( $exporting_package => 1 );
55 return uniq( _follow_also_real($exporting_package) );
58 sub _follow_also_real {
59 my $exporting_package = shift;
61 die "Package in also ($exporting_package) does not seem to use MooseX::Exporter"
62 unless exists $EXPORT_SPEC{$exporting_package};
64 my $also = $EXPORT_SPEC{$exporting_package}{also};
66 return unless defined $also;
68 my @also = ref $also ? @{$also} : $also;
70 for my $package (@also)
72 die "Circular reference in also parameter to MooseX::Exporter between $exporting_package and $package"
78 return @also, map { _follow_also_real($_) } @also;
82 sub _make_sub_exporter_params {
88 for my $package (@packages) {
89 my $args = $EXPORT_SPEC{$package}
90 or die "The $package package does not use Moose::Exporter\n";
92 for my $name ( @{ $args->{with_caller} } ) {
95 \&{ $package . '::' . $name };
98 $exports{$name} = $class->_make_wrapped_sub(
105 for my $name ( @{ $args->{as_is} } ) {
110 $name = ( Class::MOP::get_code_info($name) )[1];
115 \&{ $package . '::' . $name };
119 $exports{$name} = sub {$sub};
127 # This variable gets closed over in each export _generator_. Then
128 # in the generator we grab the value and close over it _again_ in
129 # the real export, so it gets captured each time the generator
132 # In the meantime, we arrange for the import method we generate to
133 # set this variable to the caller each time it is called.
135 # This is all a bit confusing, but it works.
138 sub _make_wrapped_sub {
140 my $exporting_package = shift;
144 # We need to set the package at import time, so that when
145 # package Foo imports has(), we capture "Foo" as the
146 # package. This lets other packages call Foo::has() and get
147 # the right package. This is done for backwards compatibility
148 # with existing production code, not because this is a good
151 my $caller = $CALLER;
152 Class::MOP::subname( $exporting_package . '::'
153 . $name => sub { $sub->( $caller, @_ ) } );
157 sub _make_import_sub {
159 my $exporter = shift;
160 my $exports_from = shift;
161 my $export_to_main = shift;
164 # I think we could use Sub::Exporter's collector feature
165 # to do this, but that would be rather gross, since that
166 # feature isn't really designed to return a value to the
167 # caller of the exporter sub.
169 # Also, this makes sure we preserve backwards compat for
170 # _get_caller, so it always sees the arguments in the
173 ($traits, @_) = Moose::Exporter::_strip_traits(@_);
175 # It's important to leave @_ as-is for the benefit of
179 $CALLER = Moose::Exporter::_get_caller(@_);
181 # this works because both pragmas set $^H (see perldoc
182 # perlvar) which affects the current compilation -
183 # i.e. the file who use'd us - which is why we don't need
184 # to do anything special to make it affect that file
185 # rather than this one (which is already compiled)
190 # we should never export to main
191 if ( $CALLER eq 'main' && ! $export_to_main ) {
193 qq{$class does not export its sugar to the 'main' package.\n};
198 for my $c ( grep { $_->can('init_meta') } $class, @{$exports_from} ) {
200 $c->init_meta( for_class => $CALLER );
204 _apply_meta_traits( $CALLER, $traits )
213 my $idx = first_index { $_ eq '-traits' } @_;
215 return ( undef, @_ ) unless $idx >= 0 && $#_ >= $idx + 1;
217 my $traits = $_[ $idx + 1 ];
221 return ( $traits, @_ );
224 sub _apply_meta_traits {
225 my ( $class, $traits ) = @_;
228 unless $traits && @$traits;
230 my $meta = $class->meta();
232 my $type = ( split /::/, ref $meta )[-1]
234 'Cannot determine metaclass type for trait application . Meta isa '
237 # We can only call does_role() on Moose::Meta::Class objects, and
238 # we can only do that on $meta->meta() if it has already had at
239 # least one trait applied to it. By default $meta->meta() returns
240 # a Class::MOP::Class object (not a Moose::Meta::Class).
242 $meta->meta()->can('does_role')
243 ? not $meta->meta()->does_role($_)
246 map { Moose::Util::resolve_metatrait_alias( $type => $_ ) } @$traits;
248 return unless @traits;
250 Moose::Util::apply_all_roles_with_method( $meta,
251 'apply_to_metaclass_instance', \@traits );
255 # 1 extra level because it's called by import so there's a layer
260 ( ref $_[1] && defined $_[1]->{into} ) ? $_[1]->{into}
261 : ( ref $_[1] && defined $_[1]->{into_level} )
262 ? caller( $offset + $_[1]->{into_level} )
266 sub _make_unimport_sub {
269 my $keywords = shift;
273 my $caller = scalar caller();
274 Moose::Exporter->_remove_keywords(
276 [ $class, @{$sources} ],
282 sub _remove_keywords {
286 my $keywords = shift;
288 my %sources = map { $_ => 1 } @{$sources};
292 # loop through the keywords ...
293 foreach my $name ( @{$keywords} ) {
296 if ( defined &{ $package . '::' . $name } ) {
297 my $keyword = \&{ $package . '::' . $name };
299 # make sure it is from us
300 my ($pkg_name) = Class::MOP::get_code_info($keyword);
301 next unless $sources{$pkg_name};
303 # and if it is from us, then undef the slot
304 delete ${ $package . '::' }{$name};
315 Moose::Exporter - make an import() and unimport() just like Moose.pm
319 package MyApp::Moose;
327 Moose::Exporter->build_export_methods(
328 export => [ 'sugar1', 'sugar2', \&Some::Random::thing ],
329 init_meta_args => { metaclass_class => 'MyApp::Meta::Class' ],
338 sugar1 'do your thing';
345 This module encapsulates the logic to export sugar functions like
346 C<Moose.pm>. It does this by building custom C<import> and C<unimport>
347 methods for your module, based on a spec your provide.
349 It also lets your "stack" Moose-alike modules so you can export
350 Moose's sugar as well as your own, along with sugar from any random
351 C<MooseX> module, as long as they all use C<Moose::Exporter>.
355 This module provides exactly one public method:
357 =head2 Moose::Exporter->build_import_methods(...)
359 When you call this method, C<Moose::Exporter> build custom C<import>
360 and C<unimport> methods for your module. The import method will export
361 the functions you specify, and you can also tell it to export
362 functions exported by some other module (like C<Moose.pm>).
364 The C<unimport> method cleans the callers namespace of all the
367 This method accepts the following parameters:
371 =item * with_caller => [ ... ]
373 This a list of function I<names only> to be exported wrapped and then
374 exported. The wrapper will pass the name of the calling package as the
375 first argument to the function. Many sugar functions need to know
376 their caller so they can get the calling package's metaclass object.
378 =item * as_is => [ ... ]
380 This a list of function names or sub references to be exported
381 as-is. You can identify a subroutine by reference, which is handy to
382 re-export some other module's functions directly by reference
383 (C<\&Some::Package::function>).
385 =item * also => $name or \@names
387 This is a list of modules which contain functions that the caller
388 wants to export. These modules must also use C<Moose::Exporter>. The
389 most common use case will be to export the functions from C<Moose.pm>.
391 C<Moose::Exporter> also makes sure all these functions get removed
392 when C<unimport> is called.
396 =head1 IMPORTING AND init_meta
398 If you want to set an alternative base object class or metaclass
399 class, simply define an C<init_meta> method in your class. The
400 C<import> method that C<Moose::Exporter> generates for you will call
401 this method (if it exists). It will always pass the caller to this
402 method via the C<for_class> parameter.
404 Most of the time, your C<init_meta> method will probably just call C<<
405 Moose->init_meta >> to do the real work:
408 shift; # our class name
409 return Moose->init_meta( @_, metaclass => 'My::Metaclass' );
414 Dave Rolsky E<lt>autarch@urth.orgE<gt>
416 This is largely a reworking of code in Moose.pm originally written by
417 Stevan Little and others.
419 =head1 COPYRIGHT AND LICENSE
421 Copyright 2008 by Infinity Interactive, Inc.
423 L<http://www.iinteractive.com>
425 This library is free software; you can redistribute it and/or modify
426 it under the same terms as Perl itself.