From: Joel VanderWerf <vjoel@...>
Date: 2005-08-08T05:05:58+09:00
Subject: Re: Adding yet another Array.new form

Nikolai Weibull wrote:
...
> module Kernel
>   def returning(value)
>     yield value
>     value
>   end
> end
...

Why call it #returning and limit its usefulness? The method can be used
just as well in assignments:

ary = returning [] do ... end

or as an argument to a method or proc.

Maybe #configure, or #construct?

  def configure(obj)
    yield obj
    obj
  end

  def m1
    configure ary = [] do
      ary << 1
      ary << 2
    end
  end

  p m1()   # ==> [1, 2]

  def m2
    configure [] do |ary|
      ary << 1
      ary << 2
    end
  end

  p m2()   # ==> [1, 2]

I've never used that, but in some cases where there is a parent-child
relationship (or a sibling relationship), I've used a #create method, as
in the following:

  def create(*args)
    klass = args.shift
    obj = klass.new(*args)
    # maybe some additional args or setup based on
    # relation between self and obj
    yield obj
    # register obj in self somehow
    obj
  end

  def m3
    create Array, 5 do |ary|
      ary[0] = 1
      ary[1] = 2
    end
  end

  p m3()   # ==> [1, 2, nil, nil, nil]

-- 
      vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407