Here's what I now know about IEEE Scheme. This matters because the charter for WG1 states: "Existing features of IEEE Scheme may be removed only if a strong case can be made that they are fundamentally flawed." (IMHO only one is, namely string-set!. But more on that later.)
As documented in the R5RS notes, () counts as true in IEEE Scheme, as in R5RS and later. In R3RS and earlier it was required to count as true; R4RS specified that () was true but acknowledged that some implementations treated it as false. R4RS distinguished between essential and inessential features. Inessential syntax is let*, do, and delay (and also one-tailed if and let-loop). The inessential procedures are list-tail, numerator, denominator, rationalize, exp, log, sin, cos, tan, asin, acos, atan (both forms), atan, sqrt, expt, make-rectangular, make-polar, real-part, imag-part, magnitude, angle, exact->inexact, inexact->exact, string-copy, string-fill!, make-vector, vector-fill!, force, with-input-from-file, with-output-to-file, char-ready? (both forms), transcript-on, transcript-off. In addition, the variable-argument versions of -, /, and apply are inessential. In IEEE Scheme, there is no such distinction. Instead, IEEE simply omits the inessential syntax and the inessential procedures char-ready?, force, list-tail, string-copy, string-fill!, transcript-off, transcript-on, vector-fill!, with-input-from-file, with-output-to-file. Furthermore, it also omits the following essential procedures: list->string, list->vector, load, string->list, vector->list. (I assume that the omission of write-char from the IEEE standard is an error, since it is referenced in the definition of display.) In R5RS, a different distinction is made between optional and non-optional procedures. The only optional procedures are load, interaction-environment, with-input-from-file, with-output-to-file, transcript-on, transcript-off, of which the first two were not in R4RS at all and the last four were inessential. None of them are in IEEE Scheme. -- If I read "upcoming" in [the newspaper] John Cowan once more, I will be downcoming http://www.ccil.org/~cowan and somebody will be outgoing. [email protected] _______________________________________________ r6rs-discuss mailing list [email protected] http://lists.r6rs.org/cgi-bin/mailman/listinfo/r6rs-discuss
