Metaprogramming

Talk on basic metaprogramming based on presentations given by Dave Thomas at QCon '06 and Patrick Farley at MountainWest RubyConf '08.

Darth Vader art by Wight.

Transcript

1. Metaprogramming
2. “Metaprogramming” by Dave Thomas at QCon ’06 “Ruby Internals” by Patrick Farley at MWRubyConf ‘08 Talks
3. •Classes •Modules •Classes are Open •Singleton Class & Method •Method Receiver •Full Object Model •Metaprogramming Examples Ruby Concepts
4. Classes Class Ninja < Human # class method def self.code_of_honor nil end # instance method def say(something) nil end end
5. Modules module Taijutsu def punch(object) object.take_damage(2, :punched) end def kick(object) object.take_damage(3, :kicked) end end class Ninja include Taijutsu # mixin end
6. Ruby2Ruby •Install: sudo gem install ruby2ruby •Usage: Ruby2Ruby.translate(MyClass, :mymethod) proc.to_ruby
7. Classes are Open class String def encrypt tr ‘a-z’, ‘b-za’ end end
8. Singleton Class & Method a = ‘foo’ def a.encrypt tr ‘a-z’, ‘b-za’ end b = ‘bar’ a.encrypt b.encrypt # error!
9. Method Receiver ‘hello’.upcase puts ‘hello’ # receiver: self
10. Full Object Model
11. Object Instance Object m_tbl naruto *klass Ninja *super m_tbl: say(something)
12. Object Instance Object m_tbl naruto *klass Ninja *super m_tbl: say(something)
13. Object Instance Object m_tbl naruto *klass Ninja *super m_tbl: say(something) Human *super m_tbl: take_damage
14. Singleton method naruto *klass Ninja *super m_tbl Object m_tbl `naruto *super m_tbl: rasengan
15. Singleton method naruto *klass Ninja *super m_tbl Object m_tbl `naruto *super m_tbl: rasengan bob *klass
16. Class method Ninja *super *klass m_tbl Object *klass m_tbl `Object *super m_tbl `Ninja *super m_tbl: code_of_honor Class *super m_tbl Module *super m_tbl
17. include Module Ninja *super *klass m_tbl Object *klass m_tbl `Object *super m_tbl `Ninja *super m_tbl: code_of_honor (IClass) *super *klass *m_tbl Taijutsu m_tbl: code_of_honor
18. Thank you Mikong Galero http://devblog.michaelgalero.com michaelgalero at gmail dot com