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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: Haskell, anyone?
Date: Wed, 18 Nov 2015 12:02:36 +0100
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Date: 2015-11-18T12:02:36+01:00
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On Wed, 18 Nov 2015 02:44:02 -0800 (PST), Hadrien Grasland wrote:

> For example, if you wanted to explain the factorial to a student who has
> never been exposed to the concept, chances are that your first approach
> wouldn't be to write on a blackboard
> 
> "fact n = n * fact (n-1)
> fact 1 = 1"
> 
> Instead, you would start with a human-readable definition that looks like this :
> 
> "fact n = n * (n-1) * (n - 2) * ... * 2 * 1"

Not really. Inductive definitions are all OK, BUT they are not given
upside-down, e.g. rather this:

   1! = 1            -- Induction basis
   (n+1)! = (n+1) * n!   -- Inductive step

or, for that mater,

  n! = 1 * 2 * 3 * ... * n

> In any case, if you are using a machine which can only perform one binary
> operation at a time, you will always need an accumulator to compute the
> final result.

Actually any machine is a FSA. Stateless computation is an oxymoron. The
sole reason of having any program running is for the side effects it
produces.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de