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;
13 use Sub::Exporter 0.980;
14 use Sub::Name qw(subname);
18 sub setup_import_methods {
19 my ( $class, %args ) = @_;
21 my $exporting_package = $args{exporting_package} ||= caller();
23 $class->build_import_methods(
25 install => [qw(import unimport init_meta)]
29 sub build_import_methods {
30 my ( $class, %args ) = @_;
32 my $exporting_package = $args{exporting_package} ||= caller();
34 $EXPORT_SPEC{$exporting_package} = \%args;
36 my @exports_from = $class->_follow_also( $exporting_package );
38 my $export_recorder = {};
40 my ( $exports, $is_removable )
41 = $class->_make_sub_exporter_params(
42 [ @exports_from, $exporting_package ], $export_recorder );
44 my $exporter = Sub::Exporter::build_exporter(
47 groups => { default => [':all'] }
52 # $args{_export_to_main} exists for backwards compat, because
53 # Moose::Util::TypeConstraints did export to main (unlike Moose &
55 $methods{import} = $class->_make_import_sub( $exporting_package,
56 $exporter, \@exports_from, $args{_export_to_main} );
58 $methods{unimport} = $class->_make_unimport_sub( $exporting_package,
59 $exports, $is_removable, $export_recorder );
61 $methods{init_meta} = $class->_make_init_meta( $exporting_package,
64 my $package = Class::MOP::Package->initialize($exporting_package);
65 for my $to_install ( @{ $args{install} || [] } ) {
66 my $symbol = '&' . $to_install;
68 unless $methods{$to_install}
69 && !$package->has_package_symbol($symbol);
70 $package->add_package_symbol( $symbol, $methods{$to_install} );
73 return ( $methods{import}, $methods{unimport}, $methods{init_meta} )
81 my $exporting_package = shift;
83 local %$seen = ( $exporting_package => 1 );
85 return uniq( _follow_also_real($exporting_package) );
88 sub _follow_also_real {
89 my $exporting_package = shift;
91 if (!exists $EXPORT_SPEC{$exporting_package}) {
92 my $loaded = Class::MOP::is_class_loaded($exporting_package);
94 die "Package in also ($exporting_package) does not seem to "
95 . "use Moose::Exporter"
96 . ($loaded ? "" : " (is it loaded?)");
99 my $also = $EXPORT_SPEC{$exporting_package}{also};
101 return unless defined $also;
103 my @also = ref $also ? @{$also} : $also;
105 for my $package (@also)
107 die "Circular reference in 'also' parameter to Moose::Exporter between $exporting_package and $package"
108 if $seen->{$package};
110 $seen->{$package} = 1;
113 return @also, map { _follow_also_real($_) } @also;
117 sub _make_sub_exporter_params {
119 my $packages = shift;
120 my $export_recorder = shift;
125 for my $package ( @{$packages} ) {
126 my $args = $EXPORT_SPEC{$package}
127 or die "The $package package does not use Moose::Exporter\n";
129 for my $name ( @{ $args->{with_meta} } ) {
130 my $sub = $class->_sub_from_package( $package, $name )
133 my $fq_name = $package . '::' . $name;
135 $exports{$name} = $class->_make_wrapped_sub_with_meta(
141 $is_removable{$name} = 1;
144 for my $name ( @{ $args->{with_caller} } ) {
145 my $sub = $class->_sub_from_package( $package, $name )
148 my $fq_name = $package . '::' . $name;
150 $exports{$name} = $class->_make_wrapped_sub(
156 $is_removable{$name} = 1;
159 for my $name ( @{ $args->{as_is} } ) {
160 my ($sub, $coderef_name);
165 # Even though Moose re-exports things from Carp &
166 # Scalar::Util, we don't want to remove those at
167 # unimport time, because the importing package may
168 # have imported them explicitly ala
170 # use Carp qw( confess );
172 # This is a hack. Since we can't know whether they
173 # really want to keep these subs or not, we err on the
174 # safe side and leave them in.
176 ( $coderef_pkg, $coderef_name )
177 = Class::MOP::get_code_info($name);
179 $is_removable{$coderef_name} = $coderef_pkg eq $package ? 1 : 0;
182 $sub = $class->_sub_from_package( $package, $name )
185 $is_removable{$name} = 1;
186 $coderef_name = $name;
189 $export_recorder->{$sub} = 1;
191 $exports{$coderef_name} = sub {$sub};
195 return ( \%exports, \%is_removable );
198 sub _sub_from_package {
205 \&{ $package . '::' . $name };
208 return $sub if defined &$sub;
211 "Trying to export undefined sub ${package}::${name}";
218 sub _make_wrapped_sub {
222 my $export_recorder = shift;
224 # We need to set the package at import time, so that when
225 # package Foo imports has(), we capture "Foo" as the
226 # package. This lets other packages call Foo::has() and get
227 # the right package. This is done for backwards compatibility
228 # with existing production code, not because this is a good
231 my $caller = $CALLER;
233 my $wrapper = $self->_curry_wrapper($sub, $fq_name, $caller);
235 my $sub = subname($fq_name => $wrapper);
237 $export_recorder->{$sub} = 1;
243 sub _make_wrapped_sub_with_meta {
247 my $export_recorder = shift;
250 my $caller = $CALLER;
252 my $wrapper = $self->_late_curry_wrapper($sub, $fq_name,
253 sub { Class::MOP::class_of(shift) } => $caller);
255 my $sub = subname($fq_name => $wrapper);
257 $export_recorder->{$sub} = 1;
269 my $wrapper = sub { $sub->(@extra, @_) };
270 if (my $proto = prototype $sub) {
271 # XXX - Perl's prototype sucks. Use & to make set_prototype
272 # ignore the fact that we're passing "private variables"
273 &Scalar::Util::set_prototype($wrapper, $proto);
278 sub _late_curry_wrapper {
286 # resolve curried arguments at runtime via this closure
287 my @curry = ( $extra->( @ex_args ) );
288 return $sub->(@curry, @_);
291 if (my $proto = prototype $sub) {
292 # XXX - Perl's prototype sucks. Use & to make set_prototype
293 # ignore the fact that we're passing "private variables"
294 &Scalar::Util::set_prototype($wrapper, $proto);
299 sub _make_import_sub {
301 my $exporting_package = shift;
302 my $exporter = shift;
303 my $exports_from = shift;
307 # I think we could use Sub::Exporter's collector feature
308 # to do this, but that would be rather gross, since that
309 # feature isn't really designed to return a value to the
310 # caller of the exporter sub.
312 # Also, this makes sure we preserve backwards compat for
313 # _get_caller, so it always sees the arguments in the
316 ( $traits, @_ ) = _strip_traits(@_);
319 ( $metaclass, @_ ) = _strip_metaclass(@_);
320 $metaclass = Moose::Util::resolve_metaclass_alias(
321 'Class' => $metaclass
322 ) if defined $metaclass && length $metaclass;
324 # Normally we could look at $_[0], but in some weird cases
325 # (involving goto &Moose::import), $_[0] ends as something
326 # else (like Squirrel).
327 my $class = $exporting_package;
329 $CALLER = _get_caller(@_);
331 # this works because both pragmas set $^H (see perldoc
332 # perlvar) which affects the current compilation -
333 # i.e. the file who use'd us - which is why we don't need
334 # to do anything special to make it affect that file
335 # rather than this one (which is already compiled)
341 for my $c ( grep { $_->can('init_meta') } $class, @{$exports_from} ) {
342 # init_meta can apply a role, which when loaded uses
343 # Moose::Exporter, which in turn sets $CALLER, so we need
344 # to protect against that.
345 local $CALLER = $CALLER;
346 $c->init_meta( for_class => $CALLER, metaclass => $metaclass );
350 if ( $did_init_meta && @{$traits} ) {
351 # The traits will use Moose::Role, which in turn uses
352 # Moose::Exporter, which in turn sets $CALLER, so we need
353 # to protect against that.
354 local $CALLER = $CALLER;
355 _apply_meta_traits( $CALLER, $traits );
357 elsif ( @{$traits} ) {
360 "Cannot provide traits when $class does not have an init_meta() method"
370 my $idx = first_index { $_ eq '-traits' } @_;
372 return ( [], @_ ) unless $idx >= 0 && $#_ >= $idx + 1;
374 my $traits = $_[ $idx + 1 ];
378 $traits = [ $traits ] unless ref $traits;
380 return ( $traits, @_ );
383 sub _strip_metaclass {
384 my $idx = first_index { $_ eq '-metaclass' } @_;
386 return ( undef, @_ ) unless $idx >= 0 && $#_ >= $idx + 1;
388 my $metaclass = $_[ $idx + 1 ];
392 return ( $metaclass, @_ );
395 sub _apply_meta_traits {
396 my ( $class, $traits ) = @_;
398 return unless @{$traits};
400 my $meta = Class::MOP::class_of($class);
402 my $type = ( split /::/, ref $meta )[-1]
403 or Moose->throw_error(
404 'Cannot determine metaclass type for trait application . Meta isa '
409 ref $_ ? $_ : Moose::Util::resolve_metatrait_alias( $type => $_ )
413 return unless @resolved_traits;
415 Moose::Util::MetaRole::apply_metaclass_roles(
417 metaclass_roles => \@resolved_traits,
422 # 1 extra level because it's called by import so there's a layer
427 ( ref $_[1] && defined $_[1]->{into} ) ? $_[1]->{into}
428 : ( ref $_[1] && defined $_[1]->{into_level} )
429 ? caller( $offset + $_[1]->{into_level} )
433 sub _make_unimport_sub {
435 my $exporting_package = shift;
437 my $is_removable = shift;
438 my $export_recorder = shift;
441 my $caller = scalar caller();
442 Moose::Exporter->_remove_keywords(
444 [ keys %{$exports} ],
451 sub _remove_keywords {
454 my $keywords = shift;
455 my $is_removable = shift;
456 my $recorded_exports = shift;
460 foreach my $name ( @{ $keywords } ) {
461 next unless $is_removable->{$name};
463 if ( defined &{ $package . '::' . $name } ) {
464 my $sub = \&{ $package . '::' . $name };
466 # make sure it is from us
467 next unless $recorded_exports->{$sub};
469 # and if it is from us, then undef the slot
470 delete ${ $package . '::' }{$name};
475 sub _make_init_meta {
486 wrapped_method_metaclass
491 application_to_class_class
492 application_to_role_class
493 application_to_instance_class)
495 $metaclass_roles{$role} = $args->{$role} if exists $args->{$role};
498 my %base_class_roles;
499 %base_class_roles = ( roles => $args->{base_class_roles} )
500 if exists $args->{base_class_roles};
502 return unless %metaclass_roles || %base_class_roles;
508 return unless Class::MOP::class_of( $options{for_class} );
510 Moose::Util::MetaRole::apply_metaclass_roles(
511 for_class => $options{for_class},
515 Moose::Util::MetaRole::apply_base_class_roles(
516 for_class => $options{for_class},
519 if Class::MOP::class_of( $options{for_class} )
520 ->isa('Moose::Meta::Class');
522 return Class::MOP::class_of( $options{for_class} );
537 Moose::Exporter - make an import() and unimport() just like Moose.pm
541 package MyApp::Moose;
546 Moose::Exporter->setup_import_methods(
547 with_meta => [ 'has_rw', 'sugar2' ],
548 as_is => [ 'sugar3', \&Some::Random::thing ],
553 my ( $meta, $name, %options ) = @_;
554 $meta->add_attribute(
574 This module encapsulates the exporting of sugar functions in a
575 C<Moose.pm>-like manner. It does this by building custom C<import>,
576 C<unimport>, and C<init_meta> methods for your module, based on a spec you
579 It also lets you "stack" Moose-alike modules so you can export Moose's sugar
580 as well as your own, along with sugar from any random C<MooseX> module, as
581 long as they all use C<Moose::Exporter>. This feature exists to let you bundle
582 a set of MooseX modules into a policy module that developers can use directly
583 instead of using Moose itself.
585 To simplify writing exporter modules, C<Moose::Exporter> also imports
586 C<strict> and C<warnings> into your exporter module, as well as into
591 This module provides two public methods:
595 =item B<< Moose::Exporter->setup_import_methods(...) >>
597 When you call this method, C<Moose::Exporter> builds custom C<import>,
598 C<unimport>, and C<init_meta> methods for your module. The C<import> method
599 will export the functions you specify, and can also re-export functions
600 exported by some other module (like C<Moose.pm>).
602 The C<unimport> method cleans the caller's namespace of all the exported
605 If you pass any parameters for L<Moose::Util::MetaRole>, this method will
606 generate an C<init_meta> for you as well (see below for details). This
607 C<init_meta> will call C<Moose::Util::MetaRole::apply_metaclass_roles> and
608 C<Moose::Util::MetaRole::apply_base_class_roles> as needed.
610 Note that if any of these methods already exist, they will not be
611 overridden, you will have to use C<build_import_methods> to get the
612 coderef that would be installed.
614 This method accepts the following parameters:
618 =item * with_meta => [ ... ]
620 This list of function I<names only> will be wrapped and then exported. The
621 wrapper will pass the metaclass object for the caller as its first argument.
623 Many sugar functions will need to use this metaclass object to do something to
626 =item * as_is => [ ... ]
628 This list of function names or sub references will be exported as-is. You can
629 identify a subroutine by reference, which is handy to re-export some other
630 module's functions directly by reference (C<\&Some::Package::function>).
632 If you do export some other package's function, this function will never be
633 removed by the C<unimport> method. The reason for this is we cannot know if
634 the caller I<also> explicitly imported the sub themselves, and therefore wants
637 =item * also => $name or \@names
639 This is a list of modules which contain functions that the caller
640 wants to export. These modules must also use C<Moose::Exporter>. The
641 most common use case will be to export the functions from C<Moose.pm>.
642 Functions specified by C<with_meta> or C<as_is> take precedence over
643 functions exported by modules specified by C<also>, so that a module
644 can selectively override functions exported by another module.
646 C<Moose::Exporter> also makes sure all these functions get removed
647 when C<unimport> is called.
651 Any of the C<*_roles> options for
652 C<Moose::Util::MetaRole::apply_metaclass_roles> and
653 C<Moose::Util::MetaRole::base_class_roles> are also acceptable.
655 =item B<< Moose::Exporter->build_import_methods(...) >>
657 Returns two or three code refs, one for C<import>, one for
658 C<unimport>, and optionally one for C<init_meta>, if the appropriate
659 options are passed in.
661 Accepts the additional C<install> option, which accepts an arrayref of method
662 names to install into your exporting package. The valid options are C<import>,
663 C<unimport>, and C<init_meta>. Calling C<setup_import_methods> is equivalent
664 to calling C<build_import_methods> with C<< install => [qw(import unimport
665 init_meta)] >> except that it doesn't also return the methods.
667 Used by C<setup_import_methods>.
671 =head1 IMPORTING AND init_meta
673 If you want to set an alternative base object class or metaclass class, see
674 above for details on how this module can call L<Moose::Util::MetaRole> for
677 If you want to do something that is not supported by this module, simply
678 define an C<init_meta> method in your class. The C<import> method that
679 C<Moose::Exporter> generates for you will call this method (if it exists). It
680 will always pass the caller to this method via the C<for_class> parameter.
682 Most of the time, your C<init_meta> method will probably just call C<<
683 Moose->init_meta >> to do the real work:
686 shift; # our class name
687 return Moose->init_meta( @_, metaclass => 'My::Metaclass' );
690 Keep in mind that C<build_import_methods> will return an C<init_meta>
691 method for you, which you can also call from within your custom
694 my ( $import, $unimport, $init_meta ) =
695 Moose::Exporter->build_import_methods( ... );
702 $class->$import(...);
707 sub unimport { goto &$unimport }
714 $class->$init_meta(...);
719 =head1 METACLASS TRAITS
721 The C<import> method generated by C<Moose::Exporter> will allow the
722 user of your module to specify metaclass traits in a C<-traits>
723 parameter passed as part of the import:
725 use Moose -traits => 'My::Meta::Trait';
727 use Moose -traits => [ 'My::Meta::Trait', 'My::Other::Trait' ];
729 These traits will be applied to the caller's metaclass
730 instance. Providing traits for an exporting class that does not create
731 a metaclass for the caller is an error.
735 Dave Rolsky E<lt>autarch@urth.orgE<gt>
737 This is largely a reworking of code in Moose.pm originally written by
738 Stevan Little and others.
740 =head1 COPYRIGHT AND LICENSE
742 Copyright 2009 by Infinity Interactive, Inc.
744 L<http://www.iinteractive.com>
746 This library is free software; you can redistribute it and/or modify
747 it under the same terms as Perl itself.