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From: Ben Bacarisse <ben.usenet@bsb.me.uk>
Newsgroups: comp.lang.c
Subject: Re: bart again (UCX64)
Date: Wed, 13 Sep 2023 03:01:33 +0100
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Xref: csiph.com comp.lang.c:175317

David Brown <david.brown@hesbynett.no> writes:

> On 12/09/2023 18:28, Bart wrote:
>> On 12/09/2023 16:17, Ben Bacarisse wrote:
>>> Malcolm McLean <malcolm.arthur.mclean@gmail.com> writes:
>>>
>> 
>>>> No we can't use Haskell.
>>>
>>> That's a shame.  The Glasgow Haskell compiler reports that in
>>>
>>>    sign :: Double -> Int
>>>    sign x | x <  0 = -1
>>>           | x == 0 =  0
>>>           | x >  0 =  1
>>>
>>> the guards are non-exhaustive.
>
> To be fair, it will also give the same warning if you replace "Double" with
> "Int".

Well that's disappointing.  I thought it was doing a more interesting
analysis that would exclude such false positives.  I must never have
written a set of guards that was not obviously exhaustive.

You do of course get a run-time error if you call sign with a NaN.

-- 
Ben.