Asp Forum
Home
|
Login
|
Register
|
Search
Forums
>
comp.lang.ruby
Turning Dwemthy's Array into a mixin
Joshua Choi
11/28/2007 2:35:00 AM
As a beginner, I'm having trouble converting the metaprogramming in
Dwemthy's Array (
http://poignantguide.ne...
) into a convenient
mixin that I can use for many classes. The trouble seems to be the
"def self." declarations, but I'm not too sure; in any
case, .metaclass and .traits don't seem to be mixing in. What should I
change?
Thanks in advance!
module Dwemthy
def self.metaclass
class << self; self; end
end
def self.traits(*given_traits)
return @traits if given_traits.empty?
attr_accessor(*given_traits)
given_traits.each do |trait|
metaclass.instance_eval do
define_method(trait) do |trait_value|
@traits ||= {}
@traits[trait] = trait_value
end
end
end
class_eval do
define_method(:initialize) do
self.class.traits.each do |k, v|
instance_variable_set("@#{k}", v)
end
end
end
end
end
1 Answer
_why
11/28/2007 5:09:00 PM
0
On Wed, Nov 28, 2007 at 11:35:00AM +0900, rbysamppi@gmail.com wrote:
> As a beginner, I'm having trouble converting the metaprogramming in
> Dwemthy's Array (
http://poignantguide.ne...
) into a convenient
> mixin that I can use for many classes. The trouble seems to be the
> "def self." declarations, but I'm not too sure; in any
> case, .metaclass and .traits don't seem to be mixing in. What should I
> change?
Hey, so, yes, this is what Dwemthy has been talking about all along,
this is exactly what caused him to start grinding his teeth and his
blood pressure went through the roof and he got a contagious clubbed
foot and so on, simply because he didn't know or have the slightest
inkling concerning append_features.
Mixins only mix instance methods. However, our friend Nobu Nakada
has just the trick. ->
http://redhanded.hobix.com/bits/hyperext...
Basically, put all the class methods in their own module. Then mix
the module into the Dwemthy module using `extend`. Then add an
`append_features` method to the Dwemthy module that mixes both into
future mixees. It's a bit of a trip, but still only about five
extra lines of code.
Nobu lays low, but he's filthy smart that one.
_why
Servizio di avviso nuovi messaggi
Ricevi direttamente nella tua mail i nuovi messaggi per
Turning Dwemthy's Array into a mixin
Inserendo la tua e-mail nella casella sotto, riceverai un avviso tramite posta elettronica ogni volta che il motore di ricerca troverà un nuovo messaggio per te
Il servizio è completamente GRATUITO!
x
Login to ForumsZone
Login with Google
Login with E-Mail & Password