use strict;
use warnings FATAL => 'all';
+use Module::Runtime;
-our $VERSION = '1.001001'; # 1.1.1
+our $VERSION = '1.002004';
-my %importers;
-
-sub _importer {
+sub _prelude {
my $target = shift;
- \($importers{$target} ||= eval qq{
- package $target;
- sub { my \$m = splice \@_, 1, 1; shift->\$m(\@_) };
- } or die "Couldn't build importer for $target: $@")
+ my ($package, $file, $line, $level)
+ = ref $target ? @{$target}{qw(package filename line level)}
+ : $target =~ /[^0-9]/ ? ($target)
+ : (undef, undef, undef, $target);
+ if (defined $level) {
+ my ($p, $fn, $ln) = caller($level + 2);
+ $package ||= $p;
+ $file ||= $fn;
+ $line ||= $ln;
+ }
+ qq{package $package;\n}
+ . ($file ? "#line $line \"$file\"\n" : '')
+}
+
+sub _make_action {
+ my ($action, $target) = @_;
+ my $version = ref $target && $target->{version};
+ eval _prelude($target)
+ . q[sub {]
+ . q[ my $module = shift;]
+ . q[ Module::Runtime::require_module($module);]
+ . (ref $target && exists $target->{version} ? q[ $module->VERSION($version);] : q[])
+ . q[ $module->].$action.q[(@_);]
+ . q[}]
+ or die "Failed to build action sub to ${action} for ${target}: $@";
}
-
sub import::into {
my ($class, $target, @args) = @_;
- $class->${_importer($target)}(import => @args);
+ _make_action(import => $target)->($class, @args);
}
sub unimport::out_of {
my ($class, $target, @args) = @_;
- $class->${_importer($target)}(unimport => @args);
+ _make_action(unimport => $target)->($class, @args);
}
1;
-
+
+__END__
+
=head1 NAME
-Import::Into - import packages into other packages
+Import::Into - Import packages into other packages
=head1 SYNOPSIS
use Import::Into;
- use Thing1 ();
- use Thing2 ();
+ # simple
+ sub import {
+ Thing1->import::into(scalar caller);
+ }
+ # multiple
sub import {
my $target = caller;
Thing1->import::into($target);
Thing2->import::into($target, qw(import arguments));
}
-Note: you don't need to do anything more clever than this provided you
-document that people wanting to re-export your module should also be using
-L<Import::Into>. In fact, for a single module you can simply do:
-
+ # by level
sub import {
- ...
- Thing1->import::into(scalar caller);
+ Thing1->import::into(1);
}
-Notably, this works:
-
+ # with exporter
use base qw(Exporter);
-
sub import {
shift->export_to_level(1);
- Thing1->import::into(scalar caller);
+ Thing1->import::into(1);
}
-Note 2: You do B<not> need to do anything to Thing1 to be able to call
-C<import::into> on it. This is a global method, and is callable on any
-package (and in fact on any object as well, although it's rarer that you'd
-want to do that).
-
-Finally, we also provide an C<unimport::out_of> to allow the exporting of the
-effect of C<no>:
-
- # unimport::out_of was added in 1.1.0 (1.001000)
+ # no My::MultiExporter == no Thing1
sub unimport {
- Moose->unimport::out_of(scalar caller); # no MyThing == no Moose
+ Thing1->unimport::out_of(scalar caller);
}
-If how and why this all works is of interest to you, please read on to the
-description immediately below.
+People wanting to re-export your module should also be using L<Import::Into>.
+Any exporter or pragma will work seamlessly.
+
+Note: You do B<not> need to make any changes to Thing1 to be able to call
+C<import::into> on it. This is a global method, and is callable on any
+package (and in fact on any object as well, although it's rarer that you'd
+want to do that).
=head1 DESCRIPTION
some use L<Moose::Exporter>, some use L<Exporter::Declare> ... and some things
are pragmas.
-If you want to re-export other things, you have to know which is which.
-L<Exporter> subclasses provide export_to_level, but if they overrode their
-import method all bets are off. L<Sub::Exporter> provides an into parameter
-but figuring out something used it isn't trivial. Pragmas need to have
-their C<import> method called directly since they affect the current unit of
-compilation.
+Exporting on someone else's behalf is harder. The exporters don't provide a
+consistent API for this, and pragmas need to have their import method called
+directly, since they effect the current unit of compilation.
+
+C<Import::Into> provides global methods to make this painless.
+
+=head1 METHODS
+
+=head2 $package->import::into( $target, @arguments );
+
+A global method, callable on any package. Loads and imports the given package
+into C<$target>. C<@arguments> are passed along to the package's import method.
+
+C<$target> can be an package name to export to, an integer for the
+caller level to export to, or a hashref with the following options:
+
+=over 4
+
+=item package
+
+The target package to export to.
+
+=item filename
+
+The apparent filename to export to. Some exporting modules, such as
+L<autodie> or L<strictures>, care about the filename they are being imported
+to.
+
+=item line
+
+The apparent line number to export to. To be combined with the C<filename>
+option.
+
+=item level
+
+The caller level to export to. This will automatically populate the
+C<package>, C<filename>, and C<line> options, making it the easiest most
+constent option.
+
+=item version
+
+A version number to check for the module. The equivalent of specifying the
+version number on a C<use> line.
+
+=back
+
+=head2 $package->unimport::out_of( $target, @arguments );
+
+Equivalent to C<import::into>, but dispatches to C<$package>'s C<unimport>
+method instead of C<import>.
+
+=head1 WHY USE THIS MODULE
+
+The APIs for exporting modules aren't consistent. L<Exporter> subclasses
+provide export_to_level, but if they overrode their import method all bets
+are off. L<Sub::Exporter> provides an into parameter but figuring out
+something used it isn't trivial. Pragmas need to have their C<import> method
+called directly since they affect the current unit of compilation.
It's ... annoying.
these approaches alone on something like L<Moose> or L<Moo> that's both
an exporter and a pragma.
-So, the complete solution is:
+So, a solution for that is:
- my $sub = eval "package $target; sub { shift->import(\@_) }";
+ use Module::Runtime;
+ my $sub = eval "package $target; sub { use_module(shift)->import(\@_) }";
$sub->($thing, @import_args);
which means that import is called from the right place for pragmas to take
effect, and from the right package for caller checking to work - and so
behaves correctly for all types of exporter, for pragmas, and for hybrids.
+Additionally, some import routines check the filename they are being imported
+to. This can be dealt with by generating a L<#line directive|perlsyn/Plain
+Old Comments (Not!)> in the eval, which will change what C<caller> reports for
+the filename when called in the importer. The filename and line number to use
+in the directive then need to be fetched using C<caller>:
+
+ my ($target, $file, $line) = caller(1);
+ my $sub = eval qq{
+ package $target;
+ #line $line "$file"
+ sub { use_module(shift)->import(\@_) }
+ };
+ $sub->($thing, @import_args);
+
+And you need to switch between these implementations depending on if you are
+targeting a specific package, or something in your call stack.
+
Remembering all this, however, is excessively irritating. So I wrote a module
so I didn't have to anymore. Loading L<Import::Into> creates a global method
C<import::into> which you can call on any package to import it into another
L<http://shadow.cat/blog/matt-s-trout/madness-with-methods> which covers
coderef abuse and the C<${\...}> syntax.
-Final note: You do still need to ensure that you already loaded C<$thing> - if
-you're receiving this from a parameter, I recommend using L<Module::Runtime>:
+And that's it.
- use Import::Into;
- use Module::Runtime qw(use_module);
+=head1 SEE ALSO
- use_module($thing)->import::into($target, @import_args);
+I gave a lightning talk on this module (and L<curry> and L<Safe::Isa>) at
+L<YAPC::NA 2013|https://www.youtube.com/watch?v=wFXWV2yY7gE&t=46m05s>.
-And that's it.
+=head1 ACKNOWLEDGEMENTS
+
+Thanks to Getty for asking "how can I get C<< use strict; use warnings; >>
+turned on for all consumers of my code?" and then "why is this not a
+module?!".
=head1 AUTHOR
=head1 CONTRIBUTORS
-None yet - maybe this software is perfect! (ahahahahahahahahaha)
+haarg - Graham Knop (cpan:HAARG) <haarg@haarg.org>
+
+Mithaldu - Christian Walde (cpan:MITHALDU) <walde.christian@gmail.com>
=head1 COPYRIGHT
This library is free software and may be distributed under the same terms
as perl itself.
+
+=cut
projects / p5sagit/Import-Into.git / blobdiff