NAME Moos - Moo s{imple,peedy,ingle} SYNOPSIS package Foos; use Moos; extends 'Boos'; has this => (); has that => 42; has other => ( builder => 'build_other', lazy => 1, ); sub BUILD { my $self = shift; # build, build, build } sub BUILDARGS { my ($self, @args) = @_; # munge, munge, munge return {%munged_args}; } DESCRIPTION Moos completes the M to Moose sequence of Perl OO modules. This one is pure Perl, no dependencies, single file and Moose compatible (for what it does). FEATURES Here's a quick list of the Moose compatible features that are supported by Moos: strict / warnings Turns on "strict" and "warnings" for you. extends For inheritance. "Moos::Object" is the default base class. package MyClass; extends 'MyBaseClass'; Supports multiple inheritance, by allowing multiple classes on a single invocation. new A constructor class method. my $object = MyClass->new(this => 'nice', that => 2); BUILD Custom object construction. If you define BUILD, it is passed the value of the new object during construction. You can modify the object. Any value you return is ignored. sub BUILD { my $self = shift; ... } Helpful exports The ever useful "blessed" (from Scalar::Util) and "confess" (from Carp) are exported to your namespace. has Accessor generator. Supports the "is", "default", "build", "lazy", "clearer", "predicate", "required" and "handles" options, described below. has this => (); NOTE: Class::XSACcessor will be used for simple accessors if it is installed. This can be disabled by setting $Moos::CAN_HAZ_XS to false or by setting the PERL_MOOS_XS_DISABLE to true. is Specify which type of attribute accessor to provide. The default is "rw", a read-write accessor. Read-only "ro" accessors are also supported. has this => ( is => "ro" ); default Specify the sub to generate a default value. has this => ( default => sub { 42 } ); builder Specify the method name to generate a default value. has this => ( builder => '_build_this' ); has that => ( builder => 1 ); # accept default name for method lazy Don't generate defaults during object construction. has this => ( builder => '_build_this', lazy => 1 ); clearer Creates a clearer method. has this => ( clearer => "clear_this" ); has that => ( clearer => 1 ); # accept default name for method predicate Creates a predicate method, which can be used to check if the attribute is set or unset. has this => ( predicate => "has_this" ); has that => ( predicate => 1 ); # accept default name for method required Require that a value for the attribute be provided to the constructor or generated during object construction. has this => ( required => 1 ); handles Delegated method calls. has wheels => (handles => [qw/ roll /]); This accepts a hashref or arrayref, but not the other possibilities offered by Moose. Note that currently all accessors are read-write by default and all unknown options are silently ignored. HAS DIFFERENCES Moos has a few differences from Moose, regarding it's accessor support (ie the 'has' function). The supported options detailed above are about the same as Moose. All other arguments are currently ignored. All generated accessors are 'rw'. So you can just say: has 'this'; has that => (); Unlike the other Mo* modules, Moos also supports just specifying the default. If the number of arguments (after the name) is an odd number, then the first value is the default. The following forms are valid: has a => 42; has b => 'string' => (lazy => 1); has c => {}; has d => [1, 2, 3, 4]; These all result in creating a Moos "default" argument. If the default is an array or hash reference, a shallow copy is made. DEV OPTIONS Moos has a couple builtin dev options. They are controlled by environment variables. PERL_MOOS_ACCESSOR_CALLS By setting this environment variable, Moos will warn everytime an accessor method is called. PERL_MOOS_XXX By setting the environment variable, Moos will export the XXX debugging keywords. WHENCE I(ngy) created Moos during Pegex development. Pegex uses a clone of Moos called Pegex::Base. Pegex is a parser framework and needs to be fast. While looking into speed issues I noted that accessor calling was the biggest hit. I tried all the various Mo* solutions and Mouse was the fastest. I was happy until I remembered that Mouse uses XS, and for various reasons this broke my toolchain (TestML, Module::Install, etc). I tried to inline Moo into one file but failed, and ended up with this. I've shared Pegex::Base as Moos in case any other projects want it. Later on, Toby added a bunch of low-cost but very handy features from Moose. ON SPEED In the end, I got Pegex to run even faster with Moos than it originally did with Mouse. I'll tell you my secret... Replace these: my $foo = $self->foo; $self->foo($foo); with: my $foo = $self->{foo}; $self->{foo} = $foo; And your code will be faster (and a bit uglier). The only time that you need to call an accessor method is when you are reading a property and it might invoke a "lazy" "builder" or "default" method. Otherwise you are just wasting time. At least with the minimal feature set offered by Moos. The PERL_MOOS_ACCESSOR_CALLS feature described above is for finding these method calls. Note that users of your module's accessor methods can still use the method calls like they would expect to. I'm sure I've missed some subtlties, and would be glad to hear opinions, but in the meantime I'm happy that my code is faster and pure Perl. SEE ALSO * M * Mo * Moo * Moos * Moose * Mouse * Mousse AUTHORS Ingy döt Net Toby Inkster COPYRIGHT AND LICENSE Copyright (c) 2012. Ingy döt Net. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See http://www.perl.com/perl/misc/Artistic.html