[r6rs-discuss] [Formal] Enumeration types should be reified

From: William D Clinger <will>
Date: Thu, 14 Jun 2007 12:01:30 -0400

Jed Davis quoting me:
> > If this is to be considered, then I would suggest
> > going further and requiring any two enumeration-type
> > objects whose universes represent the same set of
> > symbols to be eqv? and interchangeable with respect
> > to all of the enumeration-set operations.
>
> That strikes me as "interesting" to implement, given that the order
> in which the symbols are passed to make-enumeration (after duplicate
> removal, if needed) is considered the "canonical order" and is used by
> enum-set-indexer and enum-set->list.

Presumably one would treat enumeration sets as true sets,
not as sequences. If the idea of a canonical order were
deemed useful, then lexicographical ordering would do
fine.

John Cowan argued against structural typing, and I don't
much care. Changing to structural typing would make more
work for me when upgrading the reference implementation.

Will
Received on Thu Jun 14 2007 - 12:01:30 UTC