On Fri, 2010-12-24 at 04:19 -0500, John Cowan wrote: > Peter Kourzanov scripsit: > > > BTW...Can someone with enough grey hairs remember why we have the horde > > of predicates like =, eq?, equal? and eqv? What I understood is that > > eqv? is sort-of one-size-fits-all idea gone astray > > EQV? is object equality, the identity of indiscernibles. EQ? is an > variant of EQV? that can answer #f on on characters and numbers in exchange > for (hopefully) better performance.
Ah, so its not that eqv? is defined to be something in-between eq? and equal? That's a connotation I had after ~5 years of looking into Scheme. > Programmers are encouraged to substitute > a different structural-equality predicate if EQUAL? doesn't suit their > needs: it is not primitive. Exactly. And how are they are supposed to branch on the outcome of their brand-new predicate? Redefine their own special (case)? > > The proposed EQUAL=? will be like EQUAL, but will employ = rather than > EQV? to compare numbers. So, the list is growing already... _______________________________________________ r6rs-discuss mailing list r6rs-discuss@lists.r6rs.org http://lists.r6rs.org/cgi-bin/mailman/listinfo/r6rs-discuss