Re: cascading message sends

On Jan 31, 2004, at 14:11, Guillaume Marcais wrote:

> What about this:
>

Nice. A little correction below:

> [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
       self

As an o's method you call may not return o itself (like bang methods). 
And this way you can have as long a chain as you need.

>   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 馗rit :
>
>> 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
>>
>>
>
>
>

Sincerely,
Gennady Bystritsky