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(@_);
373 # Normally we could look at $_[0], but in some weird cases
374 # (involving goto &Moose::import), $_[0] ends as something
375 # else (like Squirrel).
376 my $class = $exporting_package;
378 $CALLER = _get_caller(@_);
380 # this works because both pragmas set $^H (see perldoc
381 # perlvar) which affects the current compilation -
382 # i.e. the file who use'd us - which is why we don't need
383 # to do anything special to make it affect that file
384 # rather than this one (which is already compiled)
389 # we should never export to main
390 if ( $CALLER eq 'main' && !$export_to_main ) {
392 qq{$class does not export its sugar to the 'main' package.\n};
397 for my $c ( grep { $_->can('init_meta') } $class, @{$exports_from} ) {
398 # init_meta can apply a role, which when loaded uses
399 # Moose::Exporter, which in turn sets $CALLER, so we need
400 # to protect against that.
401 local $CALLER = $CALLER;
402 $c->init_meta( for_class => $CALLER, metaclass => $metaclass );
406 if ( $did_init_meta && @{$traits} ) {
407 # The traits will use Moose::Role, which in turn uses
408 # Moose::Exporter, which in turn sets $CALLER, so we need
409 # to protect against that.
410 local $CALLER = $CALLER;
411 _apply_meta_traits( $CALLER, $traits );
413 elsif ( @{$traits} ) {
416 "Cannot provide traits when $class does not have an init_meta() method"
426 my $idx = first_index { $_ eq '-traits' } @_;
428 return ( [], @_ ) unless $idx >= 0 && $#_ >= $idx + 1;
430 my $traits = $_[ $idx + 1 ];
434 $traits = [ $traits ] unless ref $traits;
436 return ( $traits, @_ );
439 sub _strip_metaclass {
440 my $idx = first_index { $_ eq '-metaclass' } @_;
442 return ( undef, @_ ) unless $idx >= 0 && $#_ >= $idx + 1;
444 my $metaclass = $_[ $idx + 1 ];
448 return ( $metaclass, @_ );
451 sub _apply_meta_traits {
452 my ( $class, $traits ) = @_;
454 return unless @{$traits};
456 my $meta = Class::MOP::class_of($class);
458 my $type = ( split /::/, ref $meta )[-1]
459 or Moose->throw_error(
460 'Cannot determine metaclass type for trait application . Meta isa '
464 = map { Moose::Util::resolve_metatrait_alias( $type => $_ ) }
467 return unless @resolved_traits;
469 Moose::Util::MetaRole::apply_metaclass_roles(
471 metaclass_roles => \@resolved_traits,
476 # 1 extra level because it's called by import so there's a layer
481 ( ref $_[1] && defined $_[1]->{into} ) ? $_[1]->{into}
482 : ( ref $_[1] && defined $_[1]->{into_level} )
483 ? caller( $offset + $_[1]->{into_level} )
487 sub _make_unimport_sub {
489 my $exporting_package = shift;
491 my $is_removable = shift;
492 my $export_recorder = shift;
495 my $caller = scalar caller();
496 Moose::Exporter->_remove_keywords(
498 [ keys %{$exports} ],
505 sub _remove_keywords {
508 my $keywords = shift;
509 my $is_removable = shift;
510 my $recorded_exports = shift;
514 foreach my $name ( @{ $keywords } ) {
515 next unless $is_removable->{$name};
517 if ( defined &{ $package . '::' . $name } ) {
518 my $sub = \&{ $package . '::' . $name };
520 # make sure it is from us
521 next unless $recorded_exports->{$sub};
523 # and if it is from us, then undef the slot
524 delete ${ $package . '::' }{$name};
540 Moose::Exporter - make an import() and unimport() just like Moose.pm
544 package MyApp::Moose;
549 Moose::Exporter->setup_import_methods(
550 with_caller => [ 'has_rw', 'sugar2' ],
551 as_is => [ 'sugar3', \&Some::Random::thing ],
556 my ($caller, $name, %options) = @_;
557 Class::MOP::class_of($caller)->add_attribute($name,
576 This module encapsulates the exporting of sugar functions in a
577 C<Moose.pm>-like manner. It does this by building custom C<import> and
578 C<unimport> methods for your module, based on a spec you provide.
580 It also lets you "stack" Moose-alike modules so you can export
581 Moose's sugar as well as your own, along with sugar from any random
582 C<MooseX> module, as long as they all use C<Moose::Exporter>.
584 To simplify writing exporter modules, C<Moose::Exporter> also imports
585 C<strict> and C<warnings> into your exporter module, as well as into
590 This module provides two public methods:
594 =item B<< Moose::Exporter->setup_import_methods(...) >>
596 When you call this method, C<Moose::Exporter> build custom C<import>
597 and C<unimport> methods for your module. The import method will export
598 the functions you specify, and you can also tell it to export
599 functions exported by some other module (like C<Moose.pm>).
601 The C<unimport> method cleans the callers namespace of all the
604 This method accepts the following parameters:
608 =item * with_caller => [ ... ]
610 This a list of function I<names only> to be exported wrapped and then
611 exported. The wrapper will pass the name of the calling package as the
612 first argument to the function. Many sugar functions need to know
613 their caller so they can get the calling package's metaclass object.
615 =item * as_is => [ ... ]
617 This a list of function names or sub references to be exported
618 as-is. You can identify a subroutine by reference, which is handy to
619 re-export some other module's functions directly by reference
620 (C<\&Some::Package::function>).
622 If you do export some other packages function, this function will
623 never be removed by the C<unimport> method. The reason for this is we
624 cannot know if the caller I<also> explicitly imported the sub
625 themselves, and therefore wants to keep it.
627 =item * also => $name or \@names
629 This is a list of modules which contain functions that the caller
630 wants to export. These modules must also use C<Moose::Exporter>. The
631 most common use case will be to export the functions from C<Moose.pm>.
632 Functions specified by C<with_caller> or C<as_is> take precedence over
633 functions exported by modules specified by C<also>, so that a module
634 can selectively override functions exported by another module.
636 C<Moose::Exporter> also makes sure all these functions get removed
637 when C<unimport> is called.
641 =item B<< Moose::Exporter->build_import_methods(...) >>
643 Returns two code refs, one for import and one for unimport.
645 Used by C<setup_import_methods>.
649 =head1 IMPORTING AND init_meta
651 If you want to set an alternative base object class or metaclass
652 class, simply define an C<init_meta> method in your class. The
653 C<import> method that C<Moose::Exporter> generates for you will call
654 this method (if it exists). It will always pass the caller to this
655 method via the C<for_class> parameter.
657 Most of the time, your C<init_meta> method will probably just call C<<
658 Moose->init_meta >> to do the real work:
661 shift; # our class name
662 return Moose->init_meta( @_, metaclass => 'My::Metaclass' );
665 =head1 METACLASS TRAITS
667 The C<import> method generated by C<Moose::Exporter> will allow the
668 user of your module to specify metaclass traits in a C<-traits>
669 parameter passed as part of the import:
671 use Moose -traits => 'My::Meta::Trait';
673 use Moose -traits => [ 'My::Meta::Trait', 'My::Other::Trait' ];
675 These traits will be applied to the caller's metaclass
676 instance. Providing traits for an exporting class that does not create
677 a metaclass for the caller is an error.
681 Dave Rolsky E<lt>autarch@urth.orgE<gt>
683 This is largely a reworking of code in Moose.pm originally written by
684 Stevan Little and others.
686 =head1 COPYRIGHT AND LICENSE
688 Copyright 2009 by Infinity Interactive, Inc.
690 L<http://www.iinteractive.com>
692 This library is free software; you can redistribute it and/or modify
693 it under the same terms as Perl itself.