Moose aims to do the same thing for Perl 5 OO. We can't actually create new keywords, but we do offer sugar that looks a lot like them. More importantly, with Moose, you define your class declaratively, without needing to know about blessed hashrefs, accessor methods, and so on.
With Moose, you can concentrate on the logical structure of your classes, focusing on what rather than how. A class definition with Moose reads like a list of very concise English sentences.
Moose is built on top of Class::MOP, a meta-object protocol
(aka MOP). Using the MOP, Moose provides complete introspection for
all Moose-using classes. This means you can ask classes about their
attributes, parents, children, methods, etc., all using a well-defined
API. The MOP abstracts away the symbol table, looking at @ISA
vars,
and all the other crufty Perl tricks we know and love(?).
Moose is based in large part on the Perl 6 object system, as well as drawing on the best ideas from CLOS, Smalltalk, and many other languages.
lhp@nereida:~/projects/perl/src/perltesting/moose$ cat -n Cat.pm 1 use 5.010; 2 { 3 package Cat; 4 use Moose; 5 use Time::localtime; 6 7 has 'name' => ( is => 'ro', isa => 'Str'); 8 has 'birth_year' => ( is => 'ro', 9 isa => 'Int', 10 default => localtime->year + 1900 11 ); 12 13 sub meow { 14 my $self = shift; 15 say 'Meow!'; 16 } 17 18 sub age { 19 my $self = shift; 20 21 1900+localtime->year-$self->birth_year(); 22 } 23 } 24 25 1;
Casiano Rodríguez León