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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: Do people who use Ada also use ocaml or F#?
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Date: Sun, 7 Nov 2010 13:14:48 +0100
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On Sun, 07 Nov 2010 11:51:32 +0000, Simon Wright wrote:

> "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> writes:
> 
>> Furthermore, I would bet that practically any generic can be broken
>> per erroneous instantiation, e.g. by passing function "-" where "+"
>> expected.  We discard these cases as unlike, but we cannot prove that
>> they indeed do not happen, until we instantiate, with is the essence
>> of being non-testable.
> 
> Good grief, most code won't give the right answers (=> answers you were
> hoping for) if you violate its preconditions!

That depends. If Read raised End_Error, while I hoped to get a Character,
was it right or wrong?

IMO one of the most important characteristics of bad design are
preconditions, which can get violated. The design is extremely bad when
they can be violated without a notice. Preconditions is what makes usage
unsafe.

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