From: "Fitzgerald,Greg" <GFITZGERALD@...>
Date: 2004-08-04T04:10:52+09:00
Subject: Closure question

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I'm trying to make a function act as a counter, but I can't seem to get
it to work.  Here's what I've tried:

def count
  counter =3D 1
  def count
    proc {counter +=3D 1}.call
  end
  counter
end


I was hoping for this:
count =3D> 1
count =3D> 2
count =3D> 3

Instead, I got this:
count =3D> 1
count =3D> NoMethodError: undefined method '+' for nil:NilClass

Isn't the idea of a closure that everything in the block is executed in
the same scope it was defined?  It seems that the name 'counter' is
referenced under the name 'count', and so when I redefine 'count', the
'counter' variable gets lost.  Anyone know what's really happening here?

Thanks,
Greg




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