Re: [boost] New Boost.XInt Library, request preliminary review

Subject: Re: [boost] New Boost.XInt Library, request preliminary review
From: Chad Nelson (chad.thecomfychair_at_[hidden])
Date: 2010-03-30 20:27:01

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On 03/30/2010 07:42 PM, Peter Dimov wrote:

>> Where am I explaining things wrong, that everyone seems to think that
>> any function can randomly return a NaN, and is complaining about it on
>> the basis of that misconception?
> 
> You stopped reading too soon. In my the next sentence, I said (quoting
> from memory):
> 
> "I don't see how checking the result of every operator/ for NaN is
> better, more readable or more expressive than checking the denominator
> for being zero beforehand"

Ah, I see... you had abbreviated operator/ to op/, and I misread it for
a typo of "operation". Sorry.

> which, as you can see, acknowledges both the rarity of functions
> returning NaN and the fact that they do so under circumstances that are
> well defined and easily checked for.

But not quite accurately, because operator/ throws an
xint::divide_by_zero under those circumstances, unless you're
deliberately blocking exceptions.

> Besides, the problem introduced by the NaN, that every function taking a
> xint must be prepared to receive it, is not affected by the number of
> functions that produce NaNs.

Why is that a problem? It's only library functions that need to be
prepared to receive a NaN, functions built on top of XInt can ignore
them and let the library catch them.
- -- 
Chad Nelson
Oak Circle Software, Inc.
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