An Eecient Abstract Machine for Curry

The functional logic programming language Curry integrates features from functional logic and concurrent programming It combines lazy evaluation higher order functions logic variables partial data struc tures built in search and the concurrent evaluation of equational con straints Curry amalgamates the most important operational principles developed in the area of integrated functional logic languages residua tion and narrowing The e ects of non determinism stemming from the narrowing semantics can be encapsulated using the primitive try oper ator This is necessary to implement declarative I O in the presence of non deterministic computations and allows to implement di erent search strategies In the present paper we develop an abstract machine for the implemen tation of Curry The focus in this paper will be on the e cient imple mentation of encapsulated search in a lazy functional logic language