From: Rick DeNatale <rick.denatale@...>
Date: 2009-07-12T23:08:05+09:00
Subject: Re: A clean way to edit a time?

On Sun, Jul 12, 2009 at 9:14 AM, David A. Black<dblack@rubypal.com> wrote:
> To start with the last point: the setter methods are engineered to
> look like and behave like assignments. So when you do this:
>
>  obj.x = y
>
> it always returns y. It's emulating assignment semantics:
>
>  x = y   # always returns y
>
> So using 'return' with an argument in those methods doesn't work.

I think to be brutally correct, it's not that a return in a setter
method doesn't work it's that

obj.x = y

will call the setter method with y as the argument, and discard any
return value.  The value of the assignment  expression will always be
the value of y, not the value returned by the setter method.

whereas obj.send("x=", y) will evaluate to the return value of the setter.

class Foo
  attr_reader :x_squared
  def x=(value)
    @x_squared = value * value
  end
end

obj = Foo.new

obj.x = 4     # => 4
obj.x_squared # => 16

obj.send("x=", 3)  # => 9
obj.x_squared        # => 9

-- 
Rick DeNatale

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