We present the design and rationale of a new statically-typed
object-oriented language, LOOM. LOOM retains most of the features of
the earlier language PolyTOIL. However the subtyping relation is
dropped from LOOM in favor of the matching relation. ``Hash types'',
which are defined in terms of matching, are introduced to provide some
of the benefits of subtyping. These types can be used to provide
support for heterogeneous data stuctures in LOOM. LOOM is considerably
simpler than PolyTOIL, yet the language is just as expressive. The
type system for the language is decidable and provably type safe. The
addition of modules to the language provides better control over
information hiding and allows the provision of access like that of
C++'s friends.