The document discusses object-oriented programming and homoiconic programming languages. It argues that Ruby's implementation of OOP differs from Alan Kay's original conception, focusing more on messaging between objects rather than treating them as data structures. Homoiconic languages like Lisp are also discussed, where the code is represented as regular data in the language, enabling powerful metaprogramming capabilities. Examples are given showing how macros and declarative programming are enabled through homoiconicity.

1. Beyond Ruby
Konstantin Haase

8. La verdadera pregunta es ...

9. ¿Quién es el mejor fútbolista?

10. Ampliar tus horizonte.
No deje Ruby ...
... evolucionar!

11. ¡Explora!

12. Por cierto ...

16. Vamos a empezar!

17. Goal: Tell you something new!
no erlang, no go, no clojure
no node.js

18. Full Object Orientation

19. Doesn't Ruby have that already?

20. OOP != OOP

21. "Objects are data and functionality."
Your high-school teacher

22. "Actually I made up the term object-oriented,
and I can tell you I did not have C++ in mind."
Alan Kay

23. "OOP to me means only messaging,
local retention and protection and hiding
of state-process, and extreme late-binding
of all things."
Alan Kay

24. "OOP to me means only messaging,
local retention and protection and hiding
of state-process, and extreme late-binding
of all things."
Alan Kay

25. if respuesta == 42
"¡correcto!"
else
"equivocado"
end

26. respuesta = 42
ifTrue: [ '¡correcto!' ]
ifFalse: [ 'equivocado' ]

27. def true.if_true
yield
end
def false.if_true
end

28. TrueClass.define_method(:if_true) { yield }
FalseClass.define_method(:if_true) { }

29. class Falso
def if_true; end
end

30. x = Delegator.new({})
x.is_a? Hash # => true
case x
when Hash
...
else
fail
end

31. Don't treat your objects like data structures!

32. my_instance.properties[:foo][1,4] == "blah"
my_instance.foo? "blah"

33. "OOP to me means only messaging,
local retention and protection and hiding
of state-process, and extreme late-binding
of all things."
Alan Kay

34. "OOP to me means only messaging,
local retention and protection and hiding
of state-process, and extreme late-binding
of all things."
Alan Kay

35. "A conforming processor may omit an
invocation of a method of a built-in class or
module for optimization purpose, and do the
same calculation as the method instead.
In this case, even if a program redefines the
method, the behavior of the program might not
change because the redefined method might not
actually be invoked."
Ruby Standard (JIS X 3017)

36. Every built-in Ruby method could actually be a
keyword.

38. Is Smalltalk Object
Oriented?

39. variable/constant access is no method send
self/super is no method send

40. Also...
no implementation treats ifTrue sends to a
boolean as method send
constants are not late bound

41. Newspeak
there are only method sends
there is no global state

42. But I want lexical scope!

43. Foo = 42
class Bar
def foo(x) Foo + x end
end

44. Outer = 23
module Wrapper
Inner = 42
class Nested
def result
Outer + Inner
end
end
end

45. Solution: clever, bidirectional dispatch

48. Homoiconic

49. "In computer programming, homoiconicity is a property of
some programming languages, in which the primary
representation of programs is also a data structure in a
primitive type of the language itself, from the Greek words
homo meaning the same and icon meaning representation.
This makes metaprogramming easier than in a language
without this property."
Wikipedia

50. "In computer programming, homoiconicity is a property of
some programming languages, in which the primary
representation of programs is also a data structure in a
primitive type of the language itself, from the Greek words
homo meaning the same and icon meaning representation.
This makes metaprogramming easier than in a language
without this property."
Wikipedia

51. "In computer programming, homoiconicity is a property of
some programming languages, in which the primary
representation of programs is also a data structure in a
primitive type of the language itself, from the Greek words
homo meaning the same and icon meaning representation.
This makes metaprogramming easier than in a language
without this property."
Wikipedia

52. "In computer programming, homoiconicity is a property of
some programming languages, in which the primary
representation of programs is also a data structure in a
primitive type of the language itself, from the Greek words
homo meaning the same and icon meaning representation.
This makes metaprogramming easier than in a language
without this property."
Wikipedia

53. Homoiconic Languages
Lisp, Logix, Prolog, Snobol, Io, Ioke, Lego

54. LISP

55. '(1 2 3)

56. (+ 1 2) ; 3

57. (setf b 23)

58. (car '(1 2)) ; 1
(cdr '(1 2)) ; '(2)
(car (cdr '(1 2))) ; 2

59. (setf a
'(setf b 23))
(eval a)

60. (setf a
'(setf b 23))
(setf
(car
(cdr (cdr a)))
42)
(eval a)

62. How's that useful?
Macros and Partial Evaluation
Language extensions from within

63. Declarative
Programming
SQL, XSLT, SPARQL, Pig

64. Did the last slide just say SQL and XSLT?
Seriously?

65. declarative programming can be fun
Prolog, Erlang

66. Prolog

67. ruby_core(tenderlove).
?- ruby_core(tenderlove).
Yes
?- ruby_core(X).
X = tenderlove

68. ruby_core(tenderlove).
rails_core(tenderlove).
ubercore(X) :-
ruby_core(X), rails_core(X).
?- ubercore(X).
X = tenderlove

69. Prolog is Lisp, kinda
car([H|_], H).
cdr([_|T], T).
?- car([1, 2, 3], X).
X = 1
?- cdr([1, 2, 3], X).
X = [2, 3]

70. Sort a list
sorted([]).
sorted([_]).
sorted([X,Y|T]) :-
X =< Y, sorted([Y|T]).
sort(X,Y) :-
perm(X,Y), sorted(Y).

72. Thanks!
github.com / rkh / presentations