From: Simen Edvardsen <toalett@...>
Date: 2007-03-17T07:34:06+09:00
Subject: Re: Anyone playing with higher order messaging in ruby?

On 3/14/07, Christoffer Lern� <lerno@dragonascendant.com> wrote:
> For example, something that I often want to do is:
>
> array.each { |entry| entry.do_something(1, "a") }
>
> [...]
>
> Other people must have played around with this.
>
> I'd like to learn more about using these methods, so are there any
> links and sites people could share with me?
>
>
> /Christoffer
>

I wrote this some time ago:

class Message
  def initialize(message, *args)
    @message, @args = message, args
  end

  def call(x, *args)
    x.send @message, *(@args + args)
  end

  def to_proc
    lambda { |*args| call(*args) }
  end
end

Now you can do:

  puts [*0..100].select(&Message.new(:>, 50)).inspect
  puts [*0..100].inject(&Message.new(:+))
  puts %w(Once upon a time).map(&Message.new(:upcase)).inspect
  puts Message.new(:index, /[aeiou]/, -3).call("hello")
  puts %w(1 2 3 4 5).map(&Message.new(:to_i)).map(&Message.new(:class)).inspect

The &Message.new syntax is a bit verbose, so you could alias it:

def _(msg, *args)
  Message.new(msg, *args)
end

And then it runs smooth:

  puts [*0..100].select(&_(:>, 50)).inspect

I don't know if this helps. It does do away with the need for
method_missing or changing core classes or stuff like that. I don't
know how useful it is, because I've never used it for anything
serious. If it was to be really useful, it should've been incorporated
into the language and standard libraries.

-- 
- Simen