From: furtive.clown@...
Date: 2007-11-13T18:45:02+09:00
Subject: Re: Whats the ruby way of associating metadata with a function

On Nov 13, 3:43 am, Keith Chapman <keithgchap...@gmail.com> wrote:
>
> In javascript I'm used to associating metadata with a function as
> follows.
>
> foo.bar = "foobar";
> function foo(){
>
> }
>
> Whats the normal ruby practice to do this kind of a thing. Whats the
> ruby way of doing this.

Three options come to mind:

==================================================
#1 : add accessors to the singleton of a lambda

foo = lambda {
   puts "foo!!"
}

class << foo
   attr_accessor :bar
end

foo.bar = "foobar"

foo.call # => "foo!!"
puts foo.bar # => "foobar"

==================================================
#2 : add a hash to the singleton of a lambda

foo = lambda {
   puts "foo!!"
}

class << foo
   def meta
      @meta ||= Hash.new
   end
end

foo.meta[:bar] = "foobar"

foo.call # => "foo!!"
puts foo.meta[:bar] # => "foobar"

==================================================
#3 : add a method to the singleton of an OpenStruct

require 'ostruct'

foo = OpenStruct.new

class << foo
   def call
      puts "foo!!"
   end
end

foo.bar = "foobar"

foo.call # => "foo!!"
puts foo.bar # => "foobar"

All other things being equal, I would be inclined toward #3.