[r6rs-discuss] Why are fx+ and fx* restricted to two arguments

From: Mikael Tillenius <mti>
Date: Tue Feb 20 11:39:12 2007

William D Clinger wrote:
> I'd like to understand your reasoning; if you are right,
> then the draft may contain an error. Section 2.2 says:
>
> If exact numbers are passed to any of the arithmetic
> procedures described in section 9.9, and an exact
> number is returned, then the result is mathematically
> correct.
>
> Section 9.9.1 says that +, -, and * must return the correct
> *exact* result provided all of its arguments are exact.
> Therefore I believe my statement was correct for those
> procedures.
>
>
To my embarrassment I must admit that I missed this. I read R4RS and
R5RS very carefully some approximately ten years ago, but I have not had
the time to read all of the R6RS draft in such detail yet. Earlier
versions of the report had (as you probably remember) a similar section
but it only required exact results for exact _integer_ arguments.

I also missed that exact rationals of practically unlimited size are now
a requirement.

Sorry for the confusion.

/Mikael
Received on Tue Feb 20 2007 - 11:40:04 UTC