Re: Partial orders. Re: Comments on SRFI 128 Draft 5 (2015-11-08). taylanbayirli@xxxxxx 10 Nov 2015 20:40 UTC
John Cowan <xxxxxx@mercury.ccil.org> writes: > Taylan Ulrich Bayırlı/Kammer scripsit: > >> It seems to be wrong, but is it? SRFI-128 says that the < must be >> transitive, but it doesn't say that the implied order= must be >> transitive. Must it be? > > = and < have to work together, and it does say that = must be transitive. > The whole point of comparators is to define a total order. Oh yes, given the mathematical definition of a total order, there doesn't seem any room for ambiguity there. I was being pedantic on the explicit properties enumerated for the ordering predicate. Then the answer to the original question > The main question here is whether the SRFI requires comparators to > totally order all elements accepted by their type-test predicates, or > whether it is OK if none (1st example) or only some (2nd) are ordered. should simply be that a total ordering is indeed required, if I'm not mistaken. After all the SRFI says: > The ordering predicate returns #t if the first object precedes the > second in a **total order**, and #f otherwise. Taylan