Re: [prolog-standard] Re: log10/1, log/2, min/2, and max/2

I have a problem with some of this discussion of max/2. If max is an
arithmetic operation then max(2, 2.0) should probably give 2.0 --
although people who mix types deserve what they get.

Jonathan

Paulo Moura wrote:
>
> On 2006/11/16, at 19:39, Jan Wielemaker wrote:
>
>> On Thursday 16 November 2006 19:37, Paulo Moura wrote:
>>>> Why is this desirable, when it leads to the problems indicated?
>>>> After all, this is an arithmetic function, so there is no reason
>>>> why it should not use the same floating-point contagion rule
>>>> like all other symmetric binary operations,
>>>
>>> Agree.
>>
>> First of all, in practice min and max are rarely used with mixed types.
>
> If that's true then...
>
>> Second, most implementations providing unbounded integer arithmetic do
>> not provide unbounded floats, so max(2<<10000, 2.0)
>
> ... this example is meaningless as it uses mixed types, correct? :-)
>
>> raises an error if
>> we promote the floats. Before that you may loose acuracy in the
>> unnecessary promotion to float. Select semantics avoids all these
>> problems.
>
> Cheers,
>
> Paulo
>
>
> -----------------------------------------------------------------
> Paulo Jorge Lopes de Moura
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Received on Mon Jul 14 2008 - 13:01:04 EST