use strictures 1;
use Moo::_Utils;
use B 'perlstring';
+use Sub::Defer ();
-our $VERSION = '0.009013'; # 0.9.13
+our $VERSION = '1.000008'; # 1.0.8
$VERSION = eval $VERSION;
+require Moo::sification;
+
our %MAKERS;
+sub _install_tracked {
+ my ($target, $name, $code) = @_;
+ $MAKERS{$target}{exports}{$name} = $code;
+ _install_coderef "${target}::${name}" => "Moo::${name}" => $code;
+}
+
sub import {
my $target = caller;
my $class = shift;
strictures->import;
- return if $MAKERS{$target}; # already exported into this package
- *{_getglob("${target}::extends")} = sub {
- _load_module($_) for @_;
- # Can't do *{...} = \@_ or 5.10.0's mro.pm stops seeing @ISA
- @{*{_getglob("${target}::ISA")}{ARRAY}} = @_;
+ if ($Moo::Role::INFO{$target} and $Moo::Role::INFO{$target}{is_role}) {
+ die "Cannot import Moo into a role";
+ }
+ $MAKERS{$target} ||= {};
+ _install_tracked $target => extends => sub {
+ $class->_set_superclasses($target, @_);
+ $class->_maybe_reset_handlemoose($target);
+ return;
};
- *{_getglob("${target}::with")} = sub {
+ _install_tracked $target => with => sub {
require Moo::Role;
- die "Only one role supported at a time by with" if @_ > 1;
- Moo::Role->apply_role_to_package($target, $_[0]);
+ Moo::Role->apply_roles_to_package($target, @_);
+ $class->_maybe_reset_handlemoose($target);
};
- $MAKERS{$target} = {};
- *{_getglob("${target}::has")} = sub {
- my ($name, %spec) = @_;
- ($MAKERS{$target}{accessor} ||= do {
- require Method::Generate::Accessor;
- Method::Generate::Accessor->new
- })->generate_method($target, $name, \%spec);
- $class->_constructor_maker_for($target)
- ->register_attribute_specs($name, \%spec);
+ _install_tracked $target => has => sub {
+ my ($name_proto, %spec) = @_;
+ my $name_isref = ref $name_proto eq 'ARRAY';
+ foreach my $name ($name_isref ? @$name_proto : $name_proto) {
+ # Note that when $name_proto is an arrayref, each attribute
+ # needs a separate \%specs hashref
+ my $spec_ref = $name_isref ? +{%spec} : \%spec;
+ $class->_constructor_maker_for($target)
+ ->register_attribute_specs($name, $spec_ref);
+ $class->_accessor_maker_for($target)
+ ->generate_method($target, $name, $spec_ref);
+ $class->_maybe_reset_handlemoose($target);
+ }
+ return;
};
foreach my $type (qw(before after around)) {
- *{_getglob "${target}::${type}"} = sub {
+ _install_tracked $target => $type => sub {
require Class::Method::Modifiers;
_install_modifier($target, $type, @_);
+ return;
};
}
+ return if $MAKERS{$target}{is_class}; # already exported into this package
+ $MAKERS{$target}{is_class} = 1;
{
no strict 'refs';
@{"${target}::ISA"} = do {
require Moo::Object; ('Moo::Object');
} unless @{"${target}::ISA"};
}
+ if ($INC{'Moo/HandleMoose.pm'}) {
+ Moo::HandleMoose::inject_fake_metaclass_for($target);
+ }
+}
+
+sub unimport {
+ my $target = caller;
+ _unimport_coderefs($target, $MAKERS{$target});
+}
+
+sub _set_superclasses {
+ my $class = shift;
+ my $target = shift;
+ foreach my $superclass (@_) {
+ _load_module($superclass);
+ if ($INC{"Role/Tiny.pm"} && $Role::Tiny::INFO{$superclass}) {
+ require Carp;
+ Carp::croak("Can't extend role '$superclass'");
+ }
+ }
+ # Can't do *{...} = \@_ or 5.10.0's mro.pm stops seeing @ISA
+ @{*{_getglob("${target}::ISA")}{ARRAY}} = @_;
+ if (my $old = delete $Moo::MAKERS{$target}{constructor}) {
+ delete _getstash($target)->{new};
+ Moo->_constructor_maker_for($target)
+ ->register_attribute_specs(%{$old->all_attribute_specs});
+ }
+ no warnings 'once'; # piss off. -- mst
+ $Moo::HandleMoose::MOUSE{$target} = [
+ grep defined, map Mouse::Util::find_meta($_), @_
+ ] if Mouse::Util->can('find_meta');
+}
+
+sub _maybe_reset_handlemoose {
+ my ($class, $target) = @_;
+ if ($INC{"Moo/HandleMoose.pm"}) {
+ Moo::HandleMoose::maybe_reinject_fake_metaclass_for($target);
+ }
+}
+
+sub _accessor_maker_for {
+ my ($class, $target) = @_;
+ return unless $MAKERS{$target};
+ $MAKERS{$target}{accessor} ||= do {
+ my $maker_class = do {
+ if (my $m = do {
+ if (my $defer_target =
+ (Sub::Defer::defer_info($target->can('new'))||[])->[0]
+ ) {
+ my ($pkg) = ($defer_target =~ /^(.*)::[^:]+$/);
+ $MAKERS{$pkg} && $MAKERS{$pkg}{accessor};
+ } else {
+ undef;
+ }
+ }) {
+ ref($m);
+ } else {
+ require Method::Generate::Accessor;
+ 'Method::Generate::Accessor'
+ }
+ };
+ $maker_class->new;
+ }
}
sub _constructor_maker_for {
$moo_constructor = 1; # no other constructor, make a Moo one
}
};
- Method::Generate::Constructor
+ ($con ? ref($con) : 'Method::Generate::Constructor')
->new(
package => $target,
- accessor_generator => do {
- require Method::Generate::Accessor;
- Method::Generate::Accessor->new;
- },
+ accessor_generator => $class->_accessor_maker_for($target),
construction_string => (
$moo_constructor
? ($con ? $con->construction_string : undef)
: ('$class->'.$target.'::SUPER::new(@_)')
),
- subconstructor_generator => (
- $class.'->_constructor_maker_for($class,'.perlstring($target).')'
+ subconstructor_handler => (
+ ' if ($Moo::MAKERS{$class}) {'."\n"
+ .' '.$class.'->_constructor_maker_for($class,'.perlstring($target).');'."\n"
+ .' return $class->new(@_)'.";\n"
+ .' } elsif ($INC{"Moose.pm"} and my $meta = Class::MOP::get_metaclass_by_name($class)) {'."\n"
+ .' return $meta->new_object($class->BUILDARGS(@_));'."\n"
+ .' }'."\n"
),
)
->install_delayed
package Cat::Food;
use Moo;
- use Sub::Quote;
sub feed_lion {
my $self = shift;
has pounds => (
is => 'rw',
- isa => quote_sub q{ die "$_[0] is too much cat food!" unless $_[0] < 15 },
+ isa => sub { die "$_[0] is too much cat food!" unless $_[0] < 15 },
);
1;
-and else where
+And elsewhere:
my $full = Cat::Food->new(
taste => 'DELICIOUS.',
=head1 DESCRIPTION
-This module is an extremely light-weight, high-performance L<Moose> replacement.
+This module is an extremely light-weight subset of L<Moose> optimised for
+rapid startup and "pay only for what you use".
+
It also avoids depending on any XS modules to allow simple deployments. The
-name C<Moo> is based on the idea that it provides almost -but not quite- two
+name C<Moo> is based on the idea that it provides almost -- but not quite -- two
thirds of L<Moose>.
-Unlike C<Mouse> this module does not aim at full L<Moose> compatibility. See
-L</INCOMPATIBILITIES> for more details.
+Unlike L<Mouse> this module does not aim at full compatibility with
+L<Moose>'s surface syntax, preferring instead of provide full interoperability
+via the metaclass inflation capabilities described in L</MOO AND MOOSE>.
+
+For a full list of the minor differences between L<Moose> and L<Moo>'s surface
+syntax, see L</INCOMPATIBILITIES WITH MOOSE>.
=head1 WHY MOO EXISTS
If you want a full object system with a rich Metaprotocol, L<Moose> is
already wonderful.
+However, sometimes you're writing a command line script or a CGI script
+where fast startup is essential, or code designed to be deployed as a single
+file via L<App::FatPacker>, or you're writing a CPAN module and you want it
+to be usable by people with those constraints.
+
I've tried several times to use L<Mouse> but it's 3x the size of Moo and
takes longer to load than most of my Moo based CGI scripts take to run.
If you don't want L<Moose>, you don't want "less metaprotocol" like L<Mouse>,
-you want "as little as possible" - which means "no metaprotocol", which is
+you want "as little as possible" -- which means "no metaprotocol", which is
what Moo provides.
-By Moo 1.0 I intend to have Moo's equivalent of L<Any::Moose> built in -
-if Moose gets loaded, any Moo class or role will act as a Moose equivalent
-if treated as such.
+Better still, if you install and load L<Moose>, we set up metaclasses for your
+L<Moo> classes and L<Moo::Role> roles, so you can use them in L<Moose> code
+without ever noticing that some of your codebase is using L<Moo>.
-Hence - Moo exists as its name - Minimal Object Orientation - with a pledge
+Hence, Moo exists as its name -- Minimal Object Orientation -- with a pledge
to make it smooth to upgrade to L<Moose> when you need more than minimal
features.
+=head1 MOO AND MOOSE
+
+If L<Moo> detects L<Moose> being loaded, it will automatically register
+metaclasses for your L<Moo> and L<Moo::Role> packages, so you should be able
+to use them in L<Moose> code without anybody ever noticing you aren't using
+L<Moose> everywhere.
+
+Extending a L<Moose> class or consuming a L<Moose::Role> will also work.
+
+So will extending a L<Mouse> class or consuming a L<Mouse::Role> - but note
+that we don't provide L<Mouse> metaclasses or metaroles so the other way
+around doesn't work. This feature exists for L<Any::Moose> users porting to
+L<Moo>; enabling L<Mouse> users to use L<Moo> classes is not a priority for us.
+
+This means that there is no need for anything like L<Any::Moose> for Moo
+code - Moo and Moose code should simply interoperate without problem. To
+handle L<Mouse> code, you'll likely need an empty Moo role or class consuming
+or extending the L<Mouse> stuff since it doesn't register true L<Moose>
+metaclasses like L<Moo> does.
+
+If you want types to be upgraded to the L<Moose> types, use
+L<MooX::Types::MooseLike> and install the L<MooseX::Types> library to
+match the L<MooX::Types::MooseLike> library you're using - L<Moo> will
+load the L<MooseX::Types> library and use that type for the newly created
+metaclass.
+
+If you need to disable the metaclass creation, add:
+
+ no Moo::sification;
+
+to your code before Moose is loaded, but bear in mind that this switch is
+currently global and turns the mechanism off entirely so don't put this
+in library code.
+
+=head1 MOO VERSUS ANY::MOOSE
+
+L<Any::Moose> will load L<Mouse> normally, and L<Moose> in a program using
+L<Moose> - which theoretically allows you to get the startup time of L<Mouse>
+without disadvantaging L<Moose> users.
+
+Sadly, this doesn't entirely work, since the selection is load order dependent
+- L<Moo>'s metaclass inflation system explained above in L</MOO AND MOOSE> is
+significantly more reliable.
+
+So if you want to write a CPAN module that loads fast or has only pure perl
+dependencies but is also fully usable by L<Moose> users, you should be using
+L<Moo>.
+
+For a full explanation, see the article
+L<http://shadow.cat/blog/matt-s-trout/moo-versus-any-moose> which explains
+the differing strategies in more detail and provides a direct example of
+where L<Moo> succeeds and L<Any::Moose> fails.
+
=head1 IMPORTED METHODS
=head2 new
=head2 BUILDARGS
- around BUILDARGS => sub {
- my $orig = shift;
+ sub BUILDARGS {
my ( $class, @args ) = @_;
unshift @args, "attr1" if @args % 2 == 1;
- return $class->$orig(@args);
+ return { @args };
};
Foo::Bar->new( 3 );
=head2 with
with 'Some::Role1';
- with 'Some::Role2';
-Composes a L<Role::Tiny> into current class. Only one role may be composed in
-at a time to allow the code to remain as simple as possible.
+or
+
+ with 'Some::Role1', 'Some::Role2';
+
+Composes one or more L<Moo::Role> (or L<Role::Tiny>) roles into the current
+class. An error will be raised if these roles have conflicting methods.
=head2 has
=item * is
-B<required>, must be C<ro> or C<rw>. Unsurprisingly, C<ro> generates an
-accessor that will not respond to arguments; to be clear: a getter only. C<rw>
-will create a perlish getter/setter.
+B<required>, may be C<ro>, C<lazy>, C<rwp> or C<rw>.
+
+C<ro> generates an accessor that dies if you attempt to write to it - i.e.
+a getter only - by defaulting C<reader> to the name of the attribute.
+
+C<lazy> generates a reader like C<ro>, but also sets C<lazy> to 1 and
+C<builder> to C<_build_${attribute_name}> to allow on-demand generated
+attributes. This feature was my attempt to fix my incompetence when
+originally designing C<lazy_build>, and is also implemented by
+L<MooseX::AttributeShortcuts>. There is, however, nothing to stop you
+using C<lazy> and C<builder> yourself with C<rwp> or C<rw> - it's just that
+this isn't generally a good idea so we don't provide a shortcut for it.
+
+C<rwp> generates a reader like C<ro>, but also sets C<writer> to
+C<_set_${attribute_name}> for attributes that are designed to be written
+from inside of the class, but read-only from outside.
+This feature comes from L<MooseX::AttributeShortcuts>.
+
+C<rw> generates a normal getter/setter by defaulting C<accessor> to the
+name of the attribute.
=item * isa
-Takes a coderef which is meant to validate the attribute. Unlike L<Moose> Moo
+Takes a coderef which is meant to validate the attribute. Unlike L<Moose>, Moo
does not include a basic type system, so instead of doing C<< isa => 'Num' >>,
one should do
- isa => quote_sub q{
+ isa => sub {
die "$_[0] is not a number!" unless looks_like_number $_[0]
},
L<Sub::Quote aware|/SUB QUOTE AWARE>
+Since L<Moo> does B<not> run the C<isa> check before C<coerce> if a coercion
+subroutine has been supplied, C<isa> checks are not structural to your code
+and can, if desired, be omitted on non-debug builds (although if this results
+in an uncaught bug causing your program to break, the L<Moo> authors guarantee
+nothing except that you get to keep both halves).
+
+If you want L<MooseX::Types> style named types, look at
+L<MooX::Types::MooseLike>.
+
+To cause your C<isa> entries to be automatically mapped to named
+L<Moose::Meta::TypeConstraint> objects (rather than the default behaviour
+of creating an anonymous type), set:
+
+ $Moo::HandleMoose::TYPE_MAP{$isa_coderef} = sub {
+ require MooseX::Types::Something;
+ return MooseX::Types::Something::TypeName();
+ };
+
+Note that this example is purely illustrative; anything that returns a
+L<Moose::Meta::TypeConstraint> object or something similar enough to it to
+make L<Moose> happy is fine.
+
=item * coerce
Takes a coderef which is meant to coerce the attribute. The basic idea is to
do something like the following:
- coerce => quote_sub q{
+ coerce => sub {
$_[0] + 1 unless $_[0] % 2
},
-Coerce does not require C<isa> to be defined.
+Note that L<Moo> will always fire your coercion: this is to permit
+C<isa> entries to be used purely for bug trapping, whereas coercions are
+always structural to your code. We do, however, apply any supplied C<isa>
+check after the coercion has run to ensure that it returned a valid value.
L<Sub::Quote aware|/SUB QUOTE AWARE>
=item * trigger
-Takes a coderef which will get called any time the attribute is set. Coderef
-will be invoked against the object with the new value as an argument.
+Takes a coderef which will get called any time the attribute is set. This
+includes the constructor. Coderef will be invoked against the object with the
+new value as an argument.
+
+If you set this to just C<1>, it generates a trigger which calls the
+C<_trigger_${attr_name}> method on C<$self>. This feature comes from
+L<MooseX::AttributeShortcuts>.
Note that Moose also passes the old value, if any; this feature is not yet
supported.
L<Sub::Quote aware|/SUB QUOTE AWARE>
-=item * default
+=item * C<default>
Takes a coderef which will get called with $self as its only argument
to populate an attribute if no value is supplied to the constructor - or
L<Sub::Quote aware|/SUB QUOTE AWARE>
-=item * predicate
+=item * C<predicate>
Takes a method name which will return true if an attribute has a value.
-A common example of this would be to call it C<has_$foo>, implying that the
-object has a C<$foo> set.
+If you set this to just C<1>, the predicate is automatically named
+C<has_${attr_name}> if your attribute's name does not start with an
+underscore, or <_has_${attr_name_without_the_underscore}> if it does.
+This feature comes from L<MooseX::AttributeShortcuts>.
-=item * builder
+=item * C<builder>
Takes a method name which will be called to create the attribute - functions
exactly like default except that instead of calling
$self->$builder;
-=item * clearer
+The following features come from L<MooseX::AttributeShortcuts>:
+
+If you set this to just C<1>, the builder is automatically named
+C<_build_${attr_name}>.
+
+If you set this to a coderef or code-convertible object, that variable will be
+installed under C<$class::_build_${attr_name}> and the builder set to the same
+name.
+
+=item * C<clearer>
Takes a method name which will clear the attribute.
-=item * lazy
+If you set this to just C<1>, the clearer is automatically named
+C<clear_${attr_name}> if your attribute's name does not start with an
+underscore, or <_clear_${attr_name_without_the_underscore}> if it does.
+This feature comes from L<MooseX::AttributeShortcuts>.
+
+=item * C<lazy>
B<Boolean>. Set this if you want values for the attribute to be grabbed
lazily. This is usually a good idea if you have a L</builder> which requires
another attribute to be set.
-=item * required
+=item * C<required>
B<Boolean>. Set this if the attribute must be passed on instantiation.
-=item * reader
+=item * C<reader>
The value of this attribute will be the name of the method to get the value of
the attribute. If you like Java style methods, you might set this to
C<get_foo>
-=item * writer
+=item * C<writer>
The value of this attribute will be the name of the method to set the value of
the attribute. If you like Java style methods, you might set this to
-C<set_foo>
+C<set_foo>.
-=item * weak_ref
+=item * C<weak_ref>
B<Boolean>. Set this if you want the reference that the attribute contains to
be weakened; use this when circular references are possible, which will cause
leaks.
-=item * init_arg
+=item * C<init_arg>
Takes the name of the key to look for at instantiation time of the object. A
common use of this is to make an underscored attribute have a non-underscored
initialization name. C<undef> means that passing the value in on instantiation
+is ignored.
=back
giving us a handy, XS-free speed boost. Any option that is L<Sub::Quote>
aware can take advantage of this.
-=head1 INCOMPATIBILITIES WITH MOOSE
+To do this, you can write
+
+ use Moo;
+ use Sub::Quote;
-You can only compose one role at a time. If your application is large or
-complex enough to warrant complex composition, you wanted L<Moose>.
+ has foo => (
+ is => 'ro',
+ isa => quote_sub(q{ die "Not <3" unless $_[0] < 3 })
+ );
+
+which will be inlined as
+
+ do {
+ local @_ = ($_[0]->{foo});
+ die "Not <3" unless $_[0] < 3;
+ }
-There is no complex type system. C<isa> is verified with a coderef, if you
+or to avoid localizing @_,
+
+ has foo => (
+ is => 'ro',
+ isa => quote_sub(q{ my ($val) = @_; die "Not <3" unless $val < 3 })
+ );
+
+which will be inlined as
+
+ do {
+ my ($val) = ($_[0]->{foo});
+ die "Not <3" unless $val < 3;
+ }
+
+See L<Sub::Quote> for more information, including how to pass lexical
+captures that will also be compiled into the subroutine.
+
+=head1 INCOMPATIBILITIES WITH MOOSE
+
+There is no built-in type system. C<isa> is verified with a coderef; if you
need complex types, just make a library of coderefs, or better yet, functions
-that return quoted subs.
+that return quoted subs. L<MooX::Types::MooseLike> provides a similar API
+to L<MooseX::Types::Moose> so that you can write
+
+ has days_to_live => (is => 'ro', isa => Int);
+
+and have it work with both; it is hoped that providing only subrefs as an
+API will encourage the use of other type systems as well, since it's
+probably the weakest part of Moose design-wise.
C<initializer> is not supported in core since the author considers it to be a
-bad idea but may be supported by an extension in future.
+bad idea but may be supported by an extension in future. Meanwhile C<trigger> or
+C<coerce> are more likely to be able to fulfill your needs.
There is no meta object. If you need this level of complexity you wanted
L<Moose> - Moo succeeds at being small because it explicitly does not
-provide a metaprotocol.
+provide a metaprotocol. However, if you load L<Moose>, then
+
+ Class::MOP::class_of($moo_class_or_role)
+
+will return an appropriate metaclass pre-populated by L<Moo>.
-No support for C<super>, C<override>, C<inner>, or C<augment> - override can
-be handled by around albeit with a little more typing, and the author considers
-augment to be a bad idea.
+No support for C<super>, C<override>, C<inner>, or C<augment> - the author
+considers augment to be a bad idea, and override can be translated:
+
+ override foo => sub {
+ ...
+ super();
+ ...
+ };
+
+ around foo => sub {
+ my ($orig, $self) = (shift, shift);
+ ...
+ $self->$orig(@_);
+ ...
+ };
+
+The C<dump> method is not provided by default. The author suggests loading
+L<Devel::Dwarn> into C<main::> (via C<perl -MDevel::Dwarn ...> for example) and
+using C<$obj-E<gt>$::Dwarn()> instead.
L</default> only supports coderefs, because doing otherwise is usually a
mistake anyway.
-C<lazy_build> is not supported per se, but of course it will work if you
-manually set all the options it implies.
+C<lazy_build> is not supported; you are instead encouraged to use the
+C<< is => 'lazy' >> option supported by L<Moo> and L<MooseX::AttributeShortcuts>.
C<auto_deref> is not supported since the author considers it a bad idea.
-C<documentation> is not supported since it's a very poor replacement for POD.
+C<documentation> will show up in a L<Moose> metaclass created from your class
+but is otherwise ignored. Then again, L<Moose> ignores it as well, so this
+is arguably not an incompatibility.
+
+Since C<coerce> does not require C<isa> to be defined but L<Moose> does
+require it, the metaclass inflation for coerce alone is a trifle insane
+and if you attempt to subtype the result will almost certainly break.
Handling of warnings: when you C<use Moo> we enable FATAL warnings. The nearest
similar invocation for L<Moose> would be:
Additionally, L<Moo> supports a set of attribute option shortcuts intended to
reduce common boilerplate. The set of shortcuts is the same as in the L<Moose>
-module L<MooseX::AttributeShortcuts>. So if you:
+module L<MooseX::AttributeShortcuts> as of its version 0.009+. So if you:
package MyClass;
use Moo;
use warnings FATAL => "all";
use MooseX::AttributeShortcuts;
+or, if you're inheriting from a non-Moose class,
+
+ package MyClass;
+
+ use Moose;
+ use MooseX::NonMoose;
+ use warnings FATAL => "all";
+ use MooseX::AttributeShortcuts;
+
+Finally, Moose requires you to call
+
+ __PACKAGE__->meta->make_immutable;
+
+at the end of your class to get an inlined (i.e. not horribly slow)
+constructor. Moo does it automatically the first time ->new is called
+on your class.
+
+An extension L<MooX::late> exists to ease translating Moose packages
+to Moo by providing a more Moose-like interface.
+
+=head1 SUPPORT
+
+Users' IRC: #moose on irc.perl.org
+
+Development and contribution IRC: #web-simple on irc.perl.org
+
=head1 AUTHOR
mst - Matt S. Trout (cpan:MSTROUT) <mst@shadowcat.co.uk>
doy - Jesse Luehrs (cpan:DOY) <doy at tozt dot net>
+perigrin - Chris Prather (cpan:PERIGRIN) <chris@prather.org>
+
+Mithaldu - Christian Walde (cpan:MITHALDU) <walde.christian@googlemail.com>
+
+ilmari - Dagfinn Ilmari Mannsåker (cpan:ILMARI) <ilmari@ilmari.org>
+
+tobyink - Toby Inkster (cpan:TOBYINK) <tobyink@cpan.org>
+
+haarg - Graham Knop (cpan:HAARG) <haarg@cpan.org>
+
=head1 COPYRIGHT
Copyright (c) 2010-2011 the Moo L</AUTHOR> and L</CONTRIBUTORS>