From: Phrogz <phrogz@...>
Date: 2010-03-30T21:40:12+09:00
Subject: Re: coercing nil/obj to false/true

On Mar 29, 10:30 pm, Steve Howell <showel...@yahoo.com> wrote:
> I can add something like this to my codebase, but I'm wondering if
> something similar is already built in:
>
> def to_boolean x
>     return !x.nil?
> end

If you really, really need exactly true or false based on the
truthiness of the value, just do:
!!x

However, I would have all your methods return either a useful value or
nil (or when appropriate, false), and just use that value in all your
boolean expressions.

For example, imagine an array-based stack. You could write:
  def top?
    !self.last.nil?
  end
but I would instead recommend just writing:
  def top
    self.last
  end
and let your users do:
  if recent = my_stack.top
    # do something with recent
  end