Andy Wingo scripsit: > FWIW -- which is probably not much, because this list does not seem to > contain a quorum of implementors --
How many would that be? My test suite currently contains 44 Schemes, and there are 75 listed in the "fairly complete list" at SchemeWiki. > Eq? is a pointer comparison operator, not an equivalence predicate. Taylan Ulrich B. scripsit: > Regarding being well-understood, in my opinion it doesn't get any > simpler than "pointer-comparison vs. operational equivalence" with no > additional constraints, and while that explanation is informal, we > already have the notion of the conceptual location tags to support a > formal explanation. The problem with that is that "pointer" is an implementation-level notion, not a user-level notion. From a user perspective, `eq?` is a fast version of `eqv?` that you can safely use on certain types and not others. While location tags formalize `eqv?`, there is no counterpart for `eq?` at all. Its behavior is horridly arbitrary, about the furthest thing possible from that famous hard, gem-like beauty that Scheme is supposed to have. -- John Cowan [email protected] I amar prestar aen, han mathon ne nen, http://www.ccil.org/~cowan han mathon ne chae, a han noston ne 'wilith. --Galadriel, LOTR:FOTR _______________________________________________ Scheme-reports mailing list [email protected] http://lists.scheme-reports.org/cgi-bin/mailman/listinfo/scheme-reports
