If you think of the equality predicate as being an equivalence relation, which I did when writing SRFI 160, then = is about all that makes sense.  If you want to compare using an arbitrary predicate, you probably want to map and then reduce the results of mapping in some way, such as using `any`.  When we write a generic sequence SRFI, it should probably provide generic map-reduce.

This SRFI is closely tied to SRFI 160, so I guess we keep its conventions.

John Cowan          http://vrici.lojban.org/~cowan        xxxxxx@ccil.org
SAXParserFactory [is] a hideous, evil monstrosity of a class that should
be hung, shot, beheaded, drawn and quartered, burned at the stake,
buried in unconsecrated ground, dug up, cremated, and the ashes tossed
in the Tiber while the complete cast of Wicked sings "Ding dong, the
witch is dead."  --Elliotte Rusty Harold on xml-dev