NAME Moo - Minimalist Object Orientation (with Moose compatiblity) WARNING WARNING WARNING This is a 0.9 release because we're fairly sure it works. For us. Until it's tested in the wild, we make no guarantees it also works for you. If this module does something unexpected, please submit a failing test. But if it eats your cat, sleeps with your boyfriend, or pushes grandma down the stairs to save her from the terrible secret of space, it's not our fault. SYNOPSIS package Cat::Food; use Moo; use Sub::Quote; sub feed_lion { my $self = shift; my $amount = shift || 1; $self->pounds( $self->pounds - $amount ); } has taste => ( is => 'ro', ); has brand => ( is => 'ro', isa => sub { die "Only SWEET-TREATZ supported!" unless $_[0] eq 'SWEET-TREATZ' }, ); has pounds => ( is => 'rw', isa => quote_sub q{ die "$_[0] is too much cat food!" unless $_[0] < 15 }, ); 1; and else where my $full = Cat::Food->new( taste => 'DELICIOUS.', brand => 'SWEET-TREATZ', pounds => 10, ); $full->feed_lion; say $full->pounds; DESCRIPTION This module is an extremely light-weight, high-performance Moose replacement. It also avoids depending on any XS modules to allow simple deployments. The name "Moo" is based on the idea that it provides almost -but not quite- two thirds of Moose. Unlike "Mouse" this module does not aim at full Moose compatibility. See "INCOMPATIBILITIES" for more details. IMPORTED METHODS new Foo::Bar->new( attr1 => 3 ); or Foo::Bar->new({ attr1 => 3 }); BUILDARGS This feature from Moose is not yet supported. BUILDALL Don't override (or probably even call) this method. Instead, you can define a "BUILD" method on your class and the constructor will automatically call the "BUILD" method from parent down to child after the object has been instantiated. Typically this is used for object validation or possibly logging. does if ($foo->does('Some::Role1')) { ... } Returns true if the object composes in the passed role. IMPORTED SUBROUTINES extends extends 'Parent::Class'; Declares base class. Multiple superclasses can be passed for multiple inheritance (but please use roles instead). Calling extends more than once will REPLACE your superclasses, not add to them like 'use base' would. with with 'Some::Role1'; with 'Some::Role2'; Composes a 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. has has attr => ( is => 'ro', ); Declares an attribute for the class. The options for "has" are as follows: * is required, must be "ro" or "rw". Unsurprisingly, "ro" generates an accessor that will not respond to arguments; to be clear: a setter only. "rw" will create a perlish getter/setter. * isa Takes a coderef which is meant to validate the attribute. Unlike Moose Moo does not include a basic type system, so instead of doing "isa => 'Num'", one should do isa => quote_sub q{ die "$_[0] is not a number!" unless looks_like_number $_[0] }, Sub::Quote aware * coerce This Moose feature is not yet supported * 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. Note that Moose also passes the old value, if any; this feature is not yet supported. Sub::Quote aware * default Takes a coderef which will get called with $self as its only argument to populate an attribute if no value is supplied to the constructor - or if the attribute is lazy, when the attribute is first retrieved if no value has yet been provided. Note that if your default is fired during new() there is no guarantee that other attributes have been populated yet so you should not rely on their existence. Sub::Quote aware * predicate Takes a method name which will return true if an attribute has a value. A common example of this would be to call it "has_$foo", implying that the object has a $foo set. * builder Takes a method name which will be called to create the attribute - functions exactly like default except that instead of calling $default->($self); Moo will call $self->$builder; * clearer Takes a method name which will clear the attribute. * lazy Boolean. Set this if you want values for the attribute to be grabbed lazily. This is usually a good idea if you have a "builder" which requires another attribute to be set. * required Boolean. Set this if the attribute must be passed on instantiation. * weak_ref 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. * 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. "undef" means that passing the value in on instantiation before before foo => sub { ... }; See "before method(s) => sub { ... }" in Class::Method::Modifiers for full documentation. around around foo => sub { ... }; See "around method(s) => sub { ... }" in Class::Method::Modifiers for full documentation. after after foo => sub { ... }; See "after method(s) => sub { ... }" in Class::Method::Modifiers for full documentation. SUB QUOTE AWARE "quote_sub" in Sub::Quote allows us to create coderefs that are "inlineable," giving us a handy, XS-free speed boost. Any option that is Sub::Quote aware can take advantage of this. INCOMPATIBILITIES WITH MOOSE You can only compose one role at a time. If your application is large or complex enough to warrant complex composition, you wanted Moose. There is no complex type system. "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. "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. There is no meta object. If you need this level of complexity you wanted Moose - Moo succeeds at being small because it explicitly does not provide a metaprotocol. No support for "super", "override", "inner", or "augment" - override can be handled by around albeit with a little more typing, and the author considers augment to be a bad idea. "default" only supports coderefs, because doing otherwise is usually a mistake anyway. "lazy_build" is not supported per se, but of course it will work if you manually set all the options it implies. "auto_deref" is not supported since the author considers it a bad idea. "documentation" is not supported since it's a very poor replacement for POD.