From: "ara.t.howard" <ara.t.howard@...>
Date: 2008-08-27T00:28:54+09:00
Subject: Re: Passing a block with define_method


On Aug 26, 2008, at 8:30 AM, James Coglan wrote:

> Hi list,
>
> I've got a bit of a problem whereby I need to pass a block to a method
> defined using define_method this works:
>
> def some_method(*args, &block)
>  # ...
> end
>
> but this does not -- the interpreter complains about unexpected  
> ampersands:
>
> define_method(:some_method) do |*args, &block|
>  # ...
> end
>
> Is there any way to make this work? I'm doing something a little  
> meta, so I
> don't know the name of the method or the number of arguments, so  
> it's all
> got to be dynamic.
>
>
>
> -- 
> James Coglan


a working example:

cfp:~ > cat a.rb
module Continuations
  Funcs = {}
  def Continuations.funcs() Funcs end

  def accepts_continuation *argv
    argv.flatten.compact.each do |arg|
      arg = arg.to_s
      klass = Class === self ? self : self.class
      Funcs[arg] = klass.send(:instance_method, arg)
      klass.module_eval <<-code
        def #{ arg }(*a, &b)
          Continuations.funcs[#{ arg.inspect }].bind(self).call(*a, &b)
        ensure
          STDERR.puts 'wrapped!'
        end
      code
    end
  end
end

def foo &b
   b.call 'bar'
end

foo{|bar| puts "foo#{ bar }"}

include Continuations
accepts_continuation :foo

foo{|bar| puts "foo#{ bar }"}



cfp:~ > ruby a.rb
foobar
foobar
wrapped!


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