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 return sub { $sub->($caller, @_) };
204 sub _make_import_sub {
206 my $exporting_package = shift;
207 my $exporter = shift;
208 my $exports_from = shift;
209 my $export_to_main = shift;
213 # I think we could use Sub::Exporter's collector feature
214 # to do this, but that would be rather gross, since that
215 # feature isn't really designed to return a value to the
216 # caller of the exporter sub.
218 # Also, this makes sure we preserve backwards compat for
219 # _get_caller, so it always sees the arguments in the
222 ( $traits, @_ ) = _strip_traits(@_);
224 # Normally we could look at $_[0], but in some weird cases
225 # (involving goto &Moose::import), $_[0] ends as something
226 # else (like Squirrel).
227 my $class = $exporting_package;
229 $CALLER = _get_caller(@_);
231 # this works because both pragmas set $^H (see perldoc
232 # perlvar) which affects the current compilation -
233 # i.e. the file who use'd us - which is why we don't need
234 # to do anything special to make it affect that file
235 # rather than this one (which is already compiled)
240 # we should never export to main
241 if ( $CALLER eq 'main' && !$export_to_main ) {
243 qq{$class does not export its sugar to the 'main' package.\n};
248 for my $c ( grep { $_->can('init_meta') } $class, @{$exports_from} ) {
249 # init_meta can apply a role, which when loaded uses
250 # Moose::Exporter, which in turn sets $CALLER, so we need
251 # to protect against that.
252 local $CALLER = $CALLER;
253 $c->init_meta( for_class => $CALLER );
257 if ( $did_init_meta && @{$traits} ) {
258 # The traits will use Moose::Role, which in turn uses
259 # Moose::Exporter, which in turn sets $CALLER, so we need
260 # to protect against that.
261 local $CALLER = $CALLER;
262 _apply_meta_traits( $CALLER, $traits );
264 elsif ( @{$traits} ) {
267 "Cannot provide traits when $class does not have an init_meta() method"
277 my $idx = first_index { $_ eq '-traits' } @_;
279 return ( [], @_ ) unless $idx >= 0 && $#_ >= $idx + 1;
281 my $traits = $_[ $idx + 1 ];
285 $traits = [ $traits ] unless ref $traits;
287 return ( $traits, @_ );
290 sub _apply_meta_traits {
291 my ( $class, $traits ) = @_;
293 return unless @{$traits};
295 my $meta = $class->meta();
297 my $type = ( split /::/, ref $meta )[-1]
298 or Moose->throw_error(
299 'Cannot determine metaclass type for trait application . Meta isa '
303 = map { Moose::Util::resolve_metatrait_alias( $type => $_ ) }
306 return unless @resolved_traits;
308 Moose::Util::MetaRole::apply_metaclass_roles(
310 metaclass_roles => \@resolved_traits,
315 # 1 extra level because it's called by import so there's a layer
320 ( ref $_[1] && defined $_[1]->{into} ) ? $_[1]->{into}
321 : ( ref $_[1] && defined $_[1]->{into_level} )
322 ? caller( $offset + $_[1]->{into_level} )
326 sub _make_unimport_sub {
328 my $exporting_package = shift;
330 my $is_removable = shift;
331 my $export_recorder = shift;
334 my $caller = scalar caller();
335 Moose::Exporter->_remove_keywords(
337 [ keys %{$exports} ],
344 sub _remove_keywords {
347 my $keywords = shift;
348 my $is_removable = shift;
349 my $recorded_exports = shift;
353 foreach my $name ( @{ $keywords } ) {
354 next unless $is_removable->{$name};
356 if ( defined &{ $package . '::' . $name } ) {
357 my $sub = \&{ $package . '::' . $name };
359 # make sure it is from us
360 next unless $recorded_exports->{$sub};
362 # and if it is from us, then undef the slot
363 delete ${ $package . '::' }{$name};
374 Moose::Exporter - make an import() and unimport() just like Moose.pm
378 package MyApp::Moose;
386 Moose::Exporter->setup_import_methods(
387 with_caller => [ 'has_rw', 'sugar2' ],
388 as_is => [ 'sugar3', \&Some::Random::thing ],
393 my ($caller, $name, %options) = @_;
394 Class::MOP::Class->initialize($caller)->add_attribute($name,
413 This module encapsulates the logic to export sugar functions like
414 C<Moose.pm>. It does this by building custom C<import> and C<unimport>
415 methods for your module, based on a spec your provide.
417 It also lets your "stack" Moose-alike modules so you can export
418 Moose's sugar as well as your own, along with sugar from any random
419 C<MooseX> module, as long as they all use C<Moose::Exporter>.
423 This module provides two public methods:
425 =head2 Moose::Exporter->setup_import_methods(...)
427 When you call this method, C<Moose::Exporter> build custom C<import>
428 and C<unimport> methods for your module. The import method will export
429 the functions you specify, and you can also tell it to export
430 functions exported by some other module (like C<Moose.pm>).
432 The C<unimport> method cleans the callers namespace of all the
435 This method accepts the following parameters:
439 =item * with_caller => [ ... ]
441 This a list of function I<names only> to be exported wrapped and then
442 exported. The wrapper will pass the name of the calling package as the
443 first argument to the function. Many sugar functions need to know
444 their caller so they can get the calling package's metaclass object.
446 =item * as_is => [ ... ]
448 This a list of function names or sub references to be exported
449 as-is. You can identify a subroutine by reference, which is handy to
450 re-export some other module's functions directly by reference
451 (C<\&Some::Package::function>).
453 If you do export some other packages function, this function will
454 never be removed by the C<unimport> method. The reason for this is we
455 cannot know if the caller I<also> explicitly imported the sub
456 themselves, and therefore wants to keep it.
458 =item * also => $name or \@names
460 This is a list of modules which contain functions that the caller
461 wants to export. These modules must also use C<Moose::Exporter>. The
462 most common use case will be to export the functions from C<Moose.pm>.
463 Functions specified by C<with_caller> or C<as_is> take precedence over
464 functions exported by modules specified by C<also>, so that a module
465 can selectively override functions exported by another module.
467 C<Moose::Exporter> also makes sure all these functions get removed
468 when C<unimport> is called.
472 =head2 Moose::Exporter->build_import_methods(...)
474 Returns two code refs, one for import and one for unimport.
476 Used by C<setup_import_methods>.
478 =head1 IMPORTING AND init_meta
480 If you want to set an alternative base object class or metaclass
481 class, simply define an C<init_meta> method in your class. The
482 C<import> method that C<Moose::Exporter> generates for you will call
483 this method (if it exists). It will always pass the caller to this
484 method via the C<for_class> parameter.
486 Most of the time, your C<init_meta> method will probably just call C<<
487 Moose->init_meta >> to do the real work:
490 shift; # our class name
491 return Moose->init_meta( @_, metaclass => 'My::Metaclass' );
494 =head1 METACLASS TRAITS
496 The C<import> method generated by C<Moose::Exporter> will allow the
497 user of your module to specify metaclass traits in a C<-traits>
498 parameter passed as part of the import:
500 use Moose -traits => 'My::Meta::Trait';
502 use Moose -traits => [ 'My::Meta::Trait', 'My::Other::Trait' ];
504 These traits will be applied to the caller's metaclass
505 instance. Providing traits for an exporting class that does not create
506 a metaclass for the caller is an error.
510 Dave Rolsky E<lt>autarch@urth.orgE<gt>
512 This is largely a reworking of code in Moose.pm originally written by
513 Stevan Little and others.
515 =head1 COPYRIGHT AND LICENSE
517 Copyright 2009 by Infinity Interactive, Inc.
519 L<http://www.iinteractive.com>
521 This library is free software; you can redistribute it and/or modify
522 it under the same terms as Perl itself.