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 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, $groups )
42 = $class->_make_sub_exporter_params(
43 [ @exports_from, $exporting_package ], $export_recorder );
45 my $exporter = Sub::Exporter::build_exporter(
48 groups => { default => [':all'], %$groups }
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 if (!exists $EXPORT_SPEC{$exporting_package}) {
80 my $loaded = Class::MOP::is_class_loaded($exporting_package);
82 die "Package in also ($exporting_package) does not seem to "
83 . "use Moose::Exporter"
84 . ($loaded ? "" : " (is it loaded?)");
87 my $also = $EXPORT_SPEC{$exporting_package}{also};
89 return unless defined $also;
91 my @also = ref $also ? @{$also} : $also;
93 for my $package (@also)
95 die "Circular reference in also parameter to Moose::Exporter between $exporting_package and $package"
98 $seen->{$package} = 1;
101 return @also, map { _follow_also_real($_) } @also;
105 sub _make_sub_exporter_params {
107 my $packages = shift;
108 my $export_recorder = shift;
114 for my $package ( @{$packages} ) {
115 my $args = $EXPORT_SPEC{$package}
116 or die "The $package package does not use Moose::Exporter\n";
118 # one group for each 'also' package
119 $groups{$package} = [
120 @{ $args->{with_caller} || [] },
121 @{ $args->{with_meta} || [] },
122 @{ $args->{as_is} || [] },
124 keys %{ $args->{groups} || {} }
127 for my $name ( @{ $args->{with_caller} } ) {
130 \&{ $package . '::' . $name };
133 my $fq_name = $package . '::' . $name;
135 $exports{$name} = $class->_make_wrapped_sub(
141 $is_removable{$name} = 1;
144 for my $name ( @{ $args->{with_meta} } ) {
147 \&{ $package . '::' . $name };
150 my $fq_name = $package . '::' . $name;
152 $exports{$name} = $class->_make_wrapped_sub_with_meta(
158 $is_removable{$name} = 1;
161 for my $name ( @{ $args->{as_is} } ) {
167 # Even though Moose re-exports things from Carp &
168 # Scalar::Util, we don't want to remove those at
169 # unimport time, because the importing package may
170 # have imported them explicitly ala
172 # use Carp qw( confess );
174 # This is a hack. Since we can't know whether they
175 # really want to keep these subs or not, we err on the
176 # safe side and leave them in.
178 ( $coderef_pkg, $name ) = Class::MOP::get_code_info($name);
180 $is_removable{$name} = $coderef_pkg eq $package ? 1 : 0;
185 \&{ $package . '::' . $name };
188 $is_removable{$name} = 1;
191 $export_recorder->{$sub} = 1;
193 $exports{$name} = sub {$sub};
196 for my $name ( keys %{ $args->{groups} } ) {
197 my $group = $args->{groups}{$name};
199 if (ref $group eq 'CODE') {
200 $groups{$name} = $class->_make_wrapped_group(
208 elsif (ref $group eq 'ARRAY') {
209 $groups{$name} = $group;
214 return ( \%exports, \%is_removable, \%groups );
219 sub _make_wrapped_sub {
223 my $export_recorder = shift;
225 # We need to set the package at import time, so that when
226 # package Foo imports has(), we capture "Foo" as the
227 # package. This lets other packages call Foo::has() and get
228 # the right package. This is done for backwards compatibility
229 # with existing production code, not because this is a good
232 my $caller = $CALLER;
234 my $wrapper = $self->_curry_wrapper($sub, $fq_name, $caller);
236 my $sub = subname($fq_name => $wrapper);
238 $export_recorder->{$sub} = 1;
244 sub _make_wrapped_sub_with_meta {
248 my $export_recorder = shift;
251 my $caller = $CALLER;
253 my $wrapper = $self->_late_curry_wrapper($sub, $fq_name,
254 sub { Class::MOP::class_of(shift) } => $caller);
256 my $sub = subname($fq_name => $wrapper);
258 $export_recorder->{$sub} = 1;
264 sub _make_wrapped_group {
266 my $package = shift; # package calling use Moose::Exporter
268 my $export_recorder = shift;
269 my $keywords = shift;
270 my $is_removable = shift;
273 my $caller = $CALLER; # package calling use PackageUsingMooseExporter -group => {args}
275 # there are plenty of ways to deal with telling the code which
276 # package it lives in. the last arg (collector hashref) is
277 # otherwise unused, so we'll stick the original package in
278 # there and act like 'with_caller' by putting the calling
279 # package name as the first arg
281 $_[3]{from} = $package;
283 my $named_code = $sub->(@_);
286 # send invalid return value error up to Sub::Exporter
287 unless (ref $named_code eq 'HASH') {
291 for my $name (keys %$named_code) {
292 my $code = $named_code->{$name};
294 my $fq_name = $package . '::' . $name;
295 my $wrapper = $class->_curry_wrapper(
301 my $sub = subname( $fq_name => $wrapper );
302 $named_code->{$name} = $sub;
304 # mark each coderef as ours
305 $keywords->{$name} = 1;
306 $is_removable->{$name} = 1;
307 $export_recorder->{$sub} = 1;
320 my $wrapper = sub { $sub->(@extra, @_) };
321 if (my $proto = prototype $sub) {
322 # XXX - Perl's prototype sucks. Use & to make set_prototype
323 # ignore the fact that we're passing "private variables"
324 &Scalar::Util::set_prototype($wrapper, $proto);
329 sub _late_curry_wrapper {
337 # resolve curried arguments at runtime via this closure
338 my @curry = ( $extra->( @ex_args ) );
339 return $sub->(@curry, @_);
342 if (my $proto = prototype $sub) {
343 # XXX - Perl's prototype sucks. Use & to make set_prototype
344 # ignore the fact that we're passing "private variables"
345 &Scalar::Util::set_prototype($wrapper, $proto);
350 sub _make_import_sub {
352 my $exporting_package = shift;
353 my $exporter = shift;
354 my $exports_from = shift;
355 my $export_to_main = shift;
359 # I think we could use Sub::Exporter's collector feature
360 # to do this, but that would be rather gross, since that
361 # feature isn't really designed to return a value to the
362 # caller of the exporter sub.
364 # Also, this makes sure we preserve backwards compat for
365 # _get_caller, so it always sees the arguments in the
368 ( $traits, @_ ) = _strip_traits(@_);
371 ( $metaclass, @_ ) = _strip_metaclass(@_);
372 $metaclass = Moose::Util::resolve_metaclass_alias(
373 'Class' => $metaclass
374 ) if defined $metaclass && length $metaclass;
376 # Normally we could look at $_[0], but in some weird cases
377 # (involving goto &Moose::import), $_[0] ends as something
378 # else (like Squirrel).
379 my $class = $exporting_package;
381 $CALLER = _get_caller(@_);
383 # this works because both pragmas set $^H (see perldoc
384 # perlvar) which affects the current compilation -
385 # i.e. the file who use'd us - which is why we don't need
386 # to do anything special to make it affect that file
387 # rather than this one (which is already compiled)
392 # we should never export to main
393 if ( $CALLER eq 'main' && !$export_to_main ) {
395 qq{$class does not export its sugar to the 'main' package.\n};
400 for my $c ( grep { $_->can('init_meta') } $class, @{$exports_from} ) {
401 # init_meta can apply a role, which when loaded uses
402 # Moose::Exporter, which in turn sets $CALLER, so we need
403 # to protect against that.
404 local $CALLER = $CALLER;
405 $c->init_meta( for_class => $CALLER, metaclass => $metaclass );
409 if ( $did_init_meta && @{$traits} ) {
410 # The traits will use Moose::Role, which in turn uses
411 # Moose::Exporter, which in turn sets $CALLER, so we need
412 # to protect against that.
413 local $CALLER = $CALLER;
414 _apply_meta_traits( $CALLER, $traits );
416 elsif ( @{$traits} ) {
419 "Cannot provide traits when $class does not have an init_meta() method"
429 my $idx = first_index { $_ eq '-traits' } @_;
431 return ( [], @_ ) unless $idx >= 0 && $#_ >= $idx + 1;
433 my $traits = $_[ $idx + 1 ];
437 $traits = [ $traits ] unless ref $traits;
439 return ( $traits, @_ );
442 sub _strip_metaclass {
443 my $idx = first_index { $_ eq '-metaclass' } @_;
445 return ( undef, @_ ) unless $idx >= 0 && $#_ >= $idx + 1;
447 my $metaclass = $_[ $idx + 1 ];
451 return ( $metaclass, @_ );
454 sub _apply_meta_traits {
455 my ( $class, $traits ) = @_;
457 return unless @{$traits};
459 my $meta = Class::MOP::class_of($class);
461 my $type = ( split /::/, ref $meta )[-1]
462 or Moose->throw_error(
463 'Cannot determine metaclass type for trait application . Meta isa '
468 ref $_ ? $_ : Moose::Util::resolve_metatrait_alias( $type => $_ )
472 return unless @resolved_traits;
474 Moose::Util::MetaRole::apply_metaclass_roles(
476 metaclass_roles => \@resolved_traits,
481 # 1 extra level because it's called by import so there's a layer
486 ( ref $_[1] && defined $_[1]->{into} ) ? $_[1]->{into}
487 : ( ref $_[1] && defined $_[1]->{into_level} )
488 ? caller( $offset + $_[1]->{into_level} )
492 sub _make_unimport_sub {
494 my $exporting_package = shift;
496 my $is_removable = shift;
497 my $export_recorder = shift;
500 my $caller = scalar caller();
501 Moose::Exporter->_remove_keywords(
503 [ keys %{$exports} ],
510 sub _remove_keywords {
513 my $keywords = shift;
514 my $is_removable = shift;
515 my $recorded_exports = shift;
519 foreach my $name ( @{ $keywords } ) {
520 next unless $is_removable->{$name};
522 if ( defined &{ $package . '::' . $name } ) {
523 my $sub = \&{ $package . '::' . $name };
525 # make sure it is from us
526 next unless $recorded_exports->{$sub};
528 # and if it is from us, then undef the slot
529 delete ${ $package . '::' }{$name};
545 Moose::Exporter - make an import() and unimport() just like Moose.pm
549 package MyApp::Moose;
554 Moose::Exporter->setup_import_methods(
555 with_caller => [ 'has_rw', 'sugar2' ],
556 as_is => [ 'sugar3', \&Some::Random::thing ],
561 my ($caller, $name, %options) = @_;
562 Class::MOP::class_of($caller)->add_attribute($name,
581 This module encapsulates the exporting of sugar functions in a
582 C<Moose.pm>-like manner. It does this by building custom C<import> and
583 C<unimport> methods for your module, based on a spec you provide.
585 It also lets you "stack" Moose-alike modules so you can export
586 Moose's sugar as well as your own, along with sugar from any random
587 C<MooseX> module, as long as they all use C<Moose::Exporter>.
589 To simplify writing exporter modules, C<Moose::Exporter> also imports
590 C<strict> and C<warnings> into your exporter module, as well as into
595 This module provides two public methods:
599 =item B<< Moose::Exporter->setup_import_methods(...) >>
601 When you call this method, C<Moose::Exporter> build custom C<import>
602 and C<unimport> methods for your module. The import method will export
603 the functions you specify, and you can also tell it to export
604 functions exported by some other module (like C<Moose.pm>).
606 The C<unimport> method cleans the callers namespace of all the
609 This method accepts the following parameters:
613 =item * with_caller => [ ... ]
615 This a list of function I<names only> to be exported wrapped and then
616 exported. The wrapper will pass the name of the calling package as the
617 first argument to the function. Many sugar functions need to know
618 their caller so they can get the calling package's metaclass object.
620 =item * as_is => [ ... ]
622 This a list of function names or sub references to be exported
623 as-is. You can identify a subroutine by reference, which is handy to
624 re-export some other module's functions directly by reference
625 (C<\&Some::Package::function>).
627 If you do export some other packages function, this function will
628 never be removed by the C<unimport> method. The reason for this is we
629 cannot know if the caller I<also> explicitly imported the sub
630 themselves, and therefore wants to keep it.
632 =item * also => $name or \@names
634 This is a list of modules which contain functions that the caller
635 wants to export. These modules must also use C<Moose::Exporter>. The
636 most common use case will be to export the functions from C<Moose.pm>.
637 Functions specified by C<with_caller> or C<as_is> take precedence over
638 functions exported by modules specified by C<also>, so that a module
639 can selectively override functions exported by another module.
641 C<Moose::Exporter> also makes sure all these functions get removed
642 when C<unimport> is called.
646 =item B<< Moose::Exporter->build_import_methods(...) >>
648 Returns two code refs, one for import and one for unimport.
650 Used by C<setup_import_methods>.
654 =head1 IMPORTING AND init_meta
656 If you want to set an alternative base object class or metaclass
657 class, simply define an C<init_meta> method in your class. The
658 C<import> method that C<Moose::Exporter> generates for you will call
659 this method (if it exists). It will always pass the caller to this
660 method via the C<for_class> parameter.
662 Most of the time, your C<init_meta> method will probably just call C<<
663 Moose->init_meta >> to do the real work:
666 shift; # our class name
667 return Moose->init_meta( @_, metaclass => 'My::Metaclass' );
670 =head1 METACLASS TRAITS
672 The C<import> method generated by C<Moose::Exporter> will allow the
673 user of your module to specify metaclass traits in a C<-traits>
674 parameter passed as part of the import:
676 use Moose -traits => 'My::Meta::Trait';
678 use Moose -traits => [ 'My::Meta::Trait', 'My::Other::Trait' ];
680 These traits will be applied to the caller's metaclass
681 instance. Providing traits for an exporting class that does not create
682 a metaclass for the caller is an error.
686 Dave Rolsky E<lt>autarch@urth.orgE<gt>
688 This is largely a reworking of code in Moose.pm originally written by
689 Stevan Little and others.
691 =head1 COPYRIGHT AND LICENSE
693 Copyright 2009 by Infinity Interactive, Inc.
695 L<http://www.iinteractive.com>
697 This library is free software; you can redistribute it and/or modify
698 it under the same terms as Perl itself.