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From: Robin Becker <robin@reportlab.com>
Subject: Re: A new module for performing tail-call elimination
Date: Thu, 16 Jul 2015 10:13:29 +0100
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On 16/07/2015 09:07, Steven D'Aprano wrote:
.........
> Fixing the obvious mistake (failing to return anything) leads to the next
> mistake. When all you have is a hammer, everything looks like a nail.
>
> def even(n):
>      return n%2 == 0
>
> def odd(n):
>      return n%2 != 0
>
......
what about

 >>> def odd(n):
... 	return bool(n%2)
...
 >>> def even(n):
... 	return not odd(n)
...

not much more complex, but the logic for A(n) and not A(n) is only done once. 
Not really much to do with TCO though.
-- 
Robin Becker