From: Todd Benson <caduceass@...>
Date: 2008-03-12T02:44:18+09:00
Subject: Re: newbie question

On Tue, Mar 11, 2008 at 6:18 AM, Benjamin Oakes
<benjamin.d.oakes@gmail.com> wrote:

>  I guess I don't understand what the point of having a = b if b is.
>  The only thing I can see that's different than a ||= b is that false
>  will become nil.  Here's what I tried:
>
>  def demo(some_value)
>   out = some_value if some_value
>   puts("out: #{out.inspect}")
>   out = nil || some_value
>   puts("out: #{out.inspect}")
>   out = some_value
>   puts("out: #{out.inspect}")
>   a_different_variable ||= some_value
>   puts("a_different_variable: #{a_different_variable.inspect}")
>   puts('------------')
>  end
>
>  demo(nil)
>  demo(88)
>  demo(false)
>
>  Outputs:
>
>  out: nil
>  out: nil
>  out: nil
>  a_different_variable: nil
>  ------------
>  out: 88
>  out: 88
>  out: 88
>  a_different_variable: 88
>  ------------
>  out: nil
>  out: false
>  out: false
>  a_different_variable: false
>  ------------
>
>  So... Why doesn't ||= work for how you're using it?  (Why do you want
>  the "b if b" behavior?)
>
>  -- Ben (aka divokz)
>
>

Because your first test will be different if "out" already exists and
is not nil.  The OP wants "out" to change only if "some_variable" is
not nil.

Todd