From: Guillaume Marcais <guslist@...>
Date: 2004-02-01T07:11:22+09:00
Subject: Re: cascading message sends

What about this:

[gus@gusmac tmp]$ cat chain.rb
#! /usr/bin/ruby -w

class Chain
   def initialize(o)
     @o = o
   end

   def method_missing(msg, *args)
     @o.send(msg, *args)
     @o
   end
end

class Object
   def chain
     Chain.new(self)
   end
end

a = [0, 1, 2, 3]
a.chain.delete_at(2).delete_at(1)
p a

[gus@gusmac tmp]$ ruby chain.rb
[0, 3]

Guillaume.

Le 31 janv. 04, � 16:19, Mark J. Reed a �crit :

> On Sat, Jan 31, 2004 at 11:16:50AM -0800, Paul MG wrote:
>> In Smalltalk, which Ruby is much like in some ways, you can 'cascade'
>> message sends. That is, call a bunch of methods on the same object
>> without naming it explicitly over and over. Eg:
>>
>>      aCollection add: 5; add: 7; add: 'foo' !
>>
>> calls 'add' on 'aCollection' 3 times, sending 5, 7, and 'foo'.
>>
>> Does Ruby have this syntax?
>
> Others have mentioned a couple ways to do this generally, but
> I just wanted to point out that you can do this without any
> special syntax as long as the methods involved return `self' -
> which many do, including Array#push:
>
>     aCollection = []
>     aCollection.push(5).push(7).push('foo')
>     [5, 7, "foo"]
>
>
> Array#<< does, too, and long chains with it have less
> syntactic clutter:
>
>
>     aCollection << 4 << 3 << 2
>     [5, 7, "foo", 4, 3, 2]
>
>
>
> -Mark
>
>