1 package Moose::Exporter;
7 $VERSION = eval $VERSION;
8 our $AUTHORITY = 'cpan:STEVAN';
11 use List::MoreUtils qw( first_index uniq );
12 use Moose::Util::MetaRole;
18 sub setup_import_methods {
19 my ( $class, %args ) = @_;
21 my $exporting_package = $args{exporting_package} ||= caller();
23 my ( $import, $unimport ) = $class->build_import_methods(%args);
26 *{ $exporting_package . '::import' } = $import;
27 *{ $exporting_package . '::unimport' } = $unimport;
30 sub build_import_methods {
31 my ( $class, %args ) = @_;
33 my $exporting_package = $args{exporting_package} ||= caller();
35 $EXPORT_SPEC{$exporting_package} = \%args;
37 my @exports_from = $class->_follow_also( $exporting_package );
39 my $export_recorder = {};
41 my ( $exports, $is_removable )
42 = $class->_make_sub_exporter_params(
43 [ @exports_from, $exporting_package ], $export_recorder );
45 my $exporter = Sub::Exporter::build_exporter(
48 groups => { default => [':all'] }
52 # $args{_export_to_main} exists for backwards compat, because
53 # Moose::Util::TypeConstraints did export to main (unlike Moose &
55 my $import = $class->_make_import_sub( $exporting_package, $exporter,
56 \@exports_from, $args{_export_to_main} );
58 my $unimport = $class->_make_unimport_sub( $exporting_package, $exports,
59 $is_removable, $export_recorder );
61 return ( $import, $unimport )
69 my $exporting_package = shift;
71 local %$seen = ( $exporting_package => 1 );
73 return uniq( _follow_also_real($exporting_package) );
76 sub _follow_also_real {
77 my $exporting_package = shift;
79 die "Package in also ($exporting_package) does not seem to use Moose::Exporter"
80 unless exists $EXPORT_SPEC{$exporting_package};
82 my $also = $EXPORT_SPEC{$exporting_package}{also};
84 return unless defined $also;
86 my @also = ref $also ? @{$also} : $also;
88 for my $package (@also)
90 die "Circular reference in also parameter to Moose::Exporter between $exporting_package and $package"
93 $seen->{$package} = 1;
96 return @also, map { _follow_also_real($_) } @also;
100 sub _make_sub_exporter_params {
102 my $packages = shift;
103 my $export_recorder = shift;
108 for my $package ( @{$packages} ) {
109 my $args = $EXPORT_SPEC{$package}
110 or die "The $package package does not use Moose::Exporter\n";
112 for my $name ( @{ $args->{with_caller} } ) {
115 \&{ $package . '::' . $name };
118 my $fq_name = $package . '::' . $name;
120 $exports{$name} = $class->_make_wrapped_sub(
126 $is_removable{$name} = 1;
129 for my $name ( @{ $args->{as_is} } ) {
135 # Even though Moose re-exports things from Carp &
136 # Scalar::Util, we don't want to remove those at
137 # unimport time, because the importing package may
138 # have imported them explicitly ala
140 # use Carp qw( confess );
142 # This is a hack. Since we can't know whether they
143 # really want to keep these subs or not, we err on the
144 # safe side and leave them in.
146 ( $coderef_pkg, $name ) = Class::MOP::get_code_info($name);
148 $is_removable{$name} = $coderef_pkg eq $package ? 1 : 0;
153 \&{ $package . '::' . $name };
156 $is_removable{$name} = 1;
159 $export_recorder->{$sub} = 1;
161 $exports{$name} = sub {$sub};
165 return ( \%exports, \%is_removable );
170 sub _make_wrapped_sub {
174 my $export_recorder = shift;
176 # We need to set the package at import time, so that when
177 # package Foo imports has(), we capture "Foo" as the
178 # package. This lets other packages call Foo::has() and get
179 # the right package. This is done for backwards compatibility
180 # with existing production code, not because this is a good
183 my $caller = $CALLER;
185 my $wrapper = $self->_make_wrapper($caller, $sub, $fq_name);
187 my $sub = Class::MOP::subname($fq_name => $wrapper);
189 $export_recorder->{$sub} = 1;
201 my $wrapper = sub { $sub->($caller, @_) };
202 if (my $proto = prototype $sub) {
203 # XXX - Perl's prototype sucks. Use & to make set_prototype
204 # ignore the fact that we're passing a "provate variable"
205 &Scalar::Util::set_prototype($wrapper, $proto);
210 sub _make_import_sub {
212 my $exporting_package = shift;
213 my $exporter = shift;
214 my $exports_from = shift;
215 my $export_to_main = shift;
219 # I think we could use Sub::Exporter's collector feature
220 # to do this, but that would be rather gross, since that
221 # feature isn't really designed to return a value to the
222 # caller of the exporter sub.
224 # Also, this makes sure we preserve backwards compat for
225 # _get_caller, so it always sees the arguments in the
228 ( $traits, @_ ) = _strip_traits(@_);
230 # Normally we could look at $_[0], but in some weird cases
231 # (involving goto &Moose::import), $_[0] ends as something
232 # else (like Squirrel).
233 my $class = $exporting_package;
235 $CALLER = _get_caller(@_);
237 # this works because both pragmas set $^H (see perldoc
238 # perlvar) which affects the current compilation -
239 # i.e. the file who use'd us - which is why we don't need
240 # to do anything special to make it affect that file
241 # rather than this one (which is already compiled)
246 # we should never export to main
247 if ( $CALLER eq 'main' && !$export_to_main ) {
249 qq{$class does not export its sugar to the 'main' package.\n};
254 for my $c ( grep { $_->can('init_meta') } $class, @{$exports_from} ) {
255 # init_meta can apply a role, which when loaded uses
256 # Moose::Exporter, which in turn sets $CALLER, so we need
257 # to protect against that.
258 local $CALLER = $CALLER;
259 $c->init_meta( for_class => $CALLER );
263 if ( $did_init_meta && @{$traits} ) {
264 # The traits will use Moose::Role, which in turn uses
265 # Moose::Exporter, which in turn sets $CALLER, so we need
266 # to protect against that.
267 local $CALLER = $CALLER;
268 _apply_meta_traits( $CALLER, $traits );
270 elsif ( @{$traits} ) {
273 "Cannot provide traits when $class does not have an init_meta() method"
283 my $idx = first_index { $_ eq '-traits' } @_;
285 return ( [], @_ ) unless $idx >= 0 && $#_ >= $idx + 1;
287 my $traits = $_[ $idx + 1 ];
291 $traits = [ $traits ] unless ref $traits;
293 return ( $traits, @_ );
296 sub _apply_meta_traits {
297 my ( $class, $traits ) = @_;
299 return unless @{$traits};
301 my $meta = Class::MOP::class_of($class);
303 my $type = ( split /::/, ref $meta )[-1]
304 or Moose->throw_error(
305 'Cannot determine metaclass type for trait application . Meta isa '
309 = map { Moose::Util::resolve_metatrait_alias( $type => $_ ) }
312 return unless @resolved_traits;
314 Moose::Util::MetaRole::apply_metaclass_roles(
316 metaclass_roles => \@resolved_traits,
321 # 1 extra level because it's called by import so there's a layer
326 ( ref $_[1] && defined $_[1]->{into} ) ? $_[1]->{into}
327 : ( ref $_[1] && defined $_[1]->{into_level} )
328 ? caller( $offset + $_[1]->{into_level} )
332 sub _make_unimport_sub {
334 my $exporting_package = shift;
336 my $is_removable = shift;
337 my $export_recorder = shift;
340 my $caller = scalar caller();
341 Moose::Exporter->_remove_keywords(
343 [ keys %{$exports} ],
350 sub _remove_keywords {
353 my $keywords = shift;
354 my $is_removable = shift;
355 my $recorded_exports = shift;
359 foreach my $name ( @{ $keywords } ) {
360 next unless $is_removable->{$name};
362 if ( defined &{ $package . '::' . $name } ) {
363 my $sub = \&{ $package . '::' . $name };
365 # make sure it is from us
366 next unless $recorded_exports->{$sub};
368 # and if it is from us, then undef the slot
369 delete ${ $package . '::' }{$name};
380 Moose::Exporter - make an import() and unimport() just like Moose.pm
384 package MyApp::Moose;
392 Moose::Exporter->setup_import_methods(
393 with_caller => [ 'has_rw', 'sugar2' ],
394 as_is => [ 'sugar3', \&Some::Random::thing ],
399 my ($caller, $name, %options) = @_;
400 Class::MOP::Class->initialize($caller)->add_attribute($name,
419 This module encapsulates the logic to export sugar functions like
420 C<Moose.pm>. It does this by building custom C<import> and C<unimport>
421 methods for your module, based on a spec your provide.
423 It also lets your "stack" Moose-alike modules so you can export
424 Moose's sugar as well as your own, along with sugar from any random
425 C<MooseX> module, as long as they all use C<Moose::Exporter>.
429 This module provides two public methods:
433 =item B<< Moose::Exporter->setup_import_methods(...) >>
435 When you call this method, C<Moose::Exporter> build custom C<import>
436 and C<unimport> methods for your module. The import method will export
437 the functions you specify, and you can also tell it to export
438 functions exported by some other module (like C<Moose.pm>).
440 The C<unimport> method cleans the callers namespace of all the
443 This method accepts the following parameters:
447 =item * with_caller => [ ... ]
449 This a list of function I<names only> to be exported wrapped and then
450 exported. The wrapper will pass the name of the calling package as the
451 first argument to the function. Many sugar functions need to know
452 their caller so they can get the calling package's metaclass object.
454 =item * as_is => [ ... ]
456 This a list of function names or sub references to be exported
457 as-is. You can identify a subroutine by reference, which is handy to
458 re-export some other module's functions directly by reference
459 (C<\&Some::Package::function>).
461 If you do export some other packages function, this function will
462 never be removed by the C<unimport> method. The reason for this is we
463 cannot know if the caller I<also> explicitly imported the sub
464 themselves, and therefore wants to keep it.
466 =item * also => $name or \@names
468 This is a list of modules which contain functions that the caller
469 wants to export. These modules must also use C<Moose::Exporter>. The
470 most common use case will be to export the functions from C<Moose.pm>.
471 Functions specified by C<with_caller> or C<as_is> take precedence over
472 functions exported by modules specified by C<also>, so that a module
473 can selectively override functions exported by another module.
475 C<Moose::Exporter> also makes sure all these functions get removed
476 when C<unimport> is called.
480 =item B<< Moose::Exporter->build_import_methods(...) >>
482 Returns two code refs, one for import and one for unimport.
484 Used by C<setup_import_methods>.
488 =head1 IMPORTING AND init_meta
490 If you want to set an alternative base object class or metaclass
491 class, simply define an C<init_meta> method in your class. The
492 C<import> method that C<Moose::Exporter> generates for you will call
493 this method (if it exists). It will always pass the caller to this
494 method via the C<for_class> parameter.
496 Most of the time, your C<init_meta> method will probably just call C<<
497 Moose->init_meta >> to do the real work:
500 shift; # our class name
501 return Moose->init_meta( @_, metaclass => 'My::Metaclass' );
504 =head1 METACLASS TRAITS
506 The C<import> method generated by C<Moose::Exporter> will allow the
507 user of your module to specify metaclass traits in a C<-traits>
508 parameter passed as part of the import:
510 use Moose -traits => 'My::Meta::Trait';
512 use Moose -traits => [ 'My::Meta::Trait', 'My::Other::Trait' ];
514 These traits will be applied to the caller's metaclass
515 instance. Providing traits for an exporting class that does not create
516 a metaclass for the caller is an error.
520 Dave Rolsky E<lt>autarch@urth.orgE<gt>
522 This is largely a reworking of code in Moose.pm originally written by
523 Stevan Little and others.
525 =head1 COPYRIGHT AND LICENSE
527 Copyright 2009 by Infinity Interactive, Inc.
529 L<http://www.iinteractive.com>
531 This library is free software; you can redistribute it and/or modify
532 it under the same terms as Perl itself.