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Re: implementation categories, exact rationals
On Oct 17, 2005, at 4:59 PM, Aubrey Jaffer wrote:
| From: Michael Sperber <sperber@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
| Date: Sun, 16 Oct 2005 21:44:10 -1000
| Aubrey Jaffer <agj@xxxxxxxxxxxx> writes:
| > What is the rationale for mandating exact rationals?
| This (from the SRFI document):
| > Under R5RS, it is hard to write programs whose arithmetic is
| > portable across the above categories, and it is unnecessarily
| > difficult even to write programs whose arithmetic is portable
| > between different implementations in the same category.
| > The portability problems can most easily be solved by requiring
| > all implementations to support the full numeric tower.
Easy for who?
Implementing exact non-integers for SCM and Guile would take a lot of
Implementing exact rationals seemed nearly trivial after the work
needed for a "good" bignum implementation. (104 lines, including
comments and whitespace, for rational +, -, *, /, versus > 2000 lines
for a reasonable set of bignum operations.)