[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: arithmetic issues

This page is part of the web mail archives of SRFI 77 from before July 7th, 2015. The new archives for SRFI 77 contain all messages, not just those from before July 7th, 2015.

Aubrey Jaffer <agj@xxxxxxxxxxxx> writes:

> That is a good point.  Of course you would want the written
> representation to match the literal form so it works for
> program-writing programs.  Argggh!
> In my experience writing lots of mathematical code, the trick is not
> generating NaNs, it is preventing them.  Searching through my 70000
> line Scheme codebase, I find no literal NaNs or infinities.

On the assumption that the literal form is rarely needed, it makes no
sense to have one.

An implementation might wisely provide a (nan) function that returns
one, however, to at least be prettier than (/ 0. 0.).  If NaNs carry
around extra origin-marking information too, the (nan) function would
be handy for that as well.