Maude-help mailing list

[pbrowne <Patrick.Browne AT comp.dit.ie>]

Marc Boyer wrote:
> It is well known from years (and this is the core of ADT) that
> the ability of a code to evolve depends on the separation of the
> implementation and the interface.

What is an interface in Maude?
An interface could consist of the sort itself, its constructors and
other operations. In Haskell the constructors are not exported. They are
not part of the interface and the Haskell Report [1] says ability to
export a type without its constructors allows the construction of
abstract datatypes. In Maude an interface could be a theory module (fth)
used to declare module. Acording to the Maude book [2] (8.3.1) fth
represents the syntactic and semantic properties to be satisfied by the
actual parameter modules used in an instantiation. If we consider
functional theories (fth) as interfaces then this similar to Goguen's
[2] *types as theories* slogan which provides a suitable theoretical
basis for extending sorts. In [4] Goguen and diaconescu implemented a
Cartesian and Polar example. I will try to implement their example in
Maude using functional theories (fth).

Regards,
Pat

[1]The Haskell Report: http://www.haskell.org/onlinereport/
[2]All About Maude: A High-Performance Logical Framework, Clavel, M., F.
Duran, et al. (2007).  Springer.
[3]Types as Theories. Goguen, J. (1991).  Topology and Category in
Computer Science. G. M. Reed, A. W. Roscoe and R. F. Wachter, Oxford
University Press: 357-390.
[4]An Oxford Survey of Order Sorted Algebra,  Goguen, J. and R.
Diaconescu (1994). Mathematical Structures in Computer Science 4: 363-392.