From: Hal Fulton <hal9000@...>
Date: 2004-11-12T08:13:04+09:00
Subject: non-nil, etc.  (was Re: true? & false?)

Gavin Sinclair wrote:
>>unless a.nil?
>>....
>>end
> 
>   if a.notnil?
>     ...
>   end
> 
> :)


You put a smiley, but in all seriousness I've thought of this.
(Actually I'd use nonnil? or nnil?)

In fact, when I'm writing code that no one else will see,
<admission type="shameful"/> I sometime use methods like these:

   a1 = []
   a2 = [1,2,3]
   s1 = ""
   s2 = "a string"
   h1 = {}
   h2 = {1=>2, 2=>4}

   a1.null?    # true
   a1.nnull?   # false
   a2.null?    # false
   a2.nnull?   # true

   s1.null?    # true
   h1.null?    # true

   # And so on...

See below, and let the flamefest begin.


Hal


   class Array
     def null?
       ! empty?
     end
   end

   class String
     def null?
       ! empty?
     end
   end

   class Hash
     def null?
       ! empty?
     end
   end

   class Fixnum
     def null?
       self == 0
     end
   end

   class File
     def null?  # now a little fun
       size == 0
     end
   end

   # And now even more fun

   class Nil
     def null?
       true
     end
     def nnil?   # for symmetry
       false
     end
   end

   # And the most fun of all, our beloved nnull?

   class Object
     def null
       false     # until overridden
     end
     def nnull?
       ! null?   # inherited by everyone
     end
   end