Summary: 4th Fuji International Symposium on Functional and Logic Programming (FLOPS'99),
Tsukuba, Japan, Nov. 1999, Springer LNCS Vol. 1722, pages 335­350.
Typed Higher­order Narrowing
without Higher­order Strategies
Sergio Antoy and Andrew Tolmach
Portland State University
Abstract. We describe a new approach to higher­order narrowing computations in
a class of systems suitable for functional logic programming. Our approach is based
on a translation of these systems into ordinary (first­order) rewrite systems and the
subsequent application of conventional narrowing strategies. Our translation is an
adaptation to narrowing of Warren's translation, but unlike similar previous work,
we preserve static type information, which has a dramatic effect on the size of the
narrowing space. Our approach supports sound, complete, and efficient higher­order
narrowing computations in classes of systems larger than those previously proposed.
1 Introduction
Functional logic languages generalize functional languages by supporting the evaluation of
expressions containing (possibly uninstantiated) logic variables. Narrowing is an essential
component of the underlying computational mechanism of an internationally supported
unified functional logic language [4]. In recent years a considerable effort has been in­
vested in the development of narrowing strategies. The results of this effort are satisfactory

Source: Antoy, Sergio - Department of Computer Science, Portland State University

Collections: Computer Technologies and Information Sciences