Copyright (C) 1994, Digital Equipment Corp.
by Steve Glassman, Mark Manasse and Greg Nelson
<*PRAGMA LL*> INTERFACERegionRep ; IMPORT Interval, Region; TYPE HList = REF ARRAY OF Interval.T; VEntry = RECORD v: Interval.T; h: HList END; VList = Region.P; REVEAL Region.P = BRANDED REF ARRAY OF VEntry; END RegionRep.