Michael Sperber scripsit: > As far as I can see, the paragraph does not say anything about > non-real numbers.
Not specifically, no. But presumably they are included in the requirement to provide a tower; that is, a system that provides only real numbers (and raises an exception of type &implementation-restriction when asked to compute any non-real number) is not conformant. > Also, I don't know what you mean by "arbitrarily". For example, would an implementation that can represent only a single non-real number, such as +i, be technically conformant? > An implementation is certainly free to restrict the ranges of non-real > numbers, however. For example, complex numbers with flonum parts were > (intended to be) within what the report says. Is an implementation that has no way to represent an exact non-real number conformant? > Could you parenthesize this? I assume you mean "bless having (exact > (or some exact) but not inexact non-real numbers)". That is what I meant, yes. > Since R6RS explicitly describes a tower, every inexact real is also a > complex number, so I think the answer is no. If an implementation may restrict the range of inexact numbers, it seems to me that technically it may restrict the range to no inexact numbers whatsoever. Is that conformant? If not, is it technically conformant to have just one inexact number, say 0.0? I ask these questions not because I think such hypothetical semi-broken implementations matter, but to help determine how (if at all) R7RS-large should tighten the requirements on implementations. There is currently consensus to require bignums and ratios, as R6RS does, but no consensus on what to require about exact and inexact non-real numbers. In particular, there are committee members who want to "do what R6RS does", but that requires being able to determine what R6RS actually does require. -- John Cowan http://www.ccil.org/~cowan co...@ccil.org They do not preach that their God will rouse them A little before the nuts work loose. They do not teach that His Pity allows them to drop their job when they damn-well choose. --Rudyard Kipling, "The Sons of Martha" _______________________________________________ r6rs-discuss mailing list r6rs-discuss@lists.r6rs.org http://lists.r6rs.org/cgi-bin/mailman/listinfo/r6rs-discuss
