Recently well-quasi orders in general, and homeomorphic embedding in particular, have gained popularity to ensure the termination of program analysis, specialisation and transformation techniques. In this paper,

Program specialisation aims at improving the overall performance of programs by performing source to source transformations. A common approach within functional and logic programming, known respectively as partial evaluation and partial deduction, is to exploit partial knowledge about the input. It is achieved through a well-automated application of parts of the Burstall-Darlington unfold/fold transformation framework. The main challenge in developing systems is to design automatic control that ensures correctness, efficiency, and termination. This survey and tutorial presents the main developments in controlling partial deduction over the past 10 years and analyses their respective merits and shortcomings. It ends with an assessment of current achievements and sketches some remaining research challenges.

Partial evaluation is a semantics-based program optimization technique which has been investigated within di#erent programming paradigms and applied to a wide variety of languages. Recently, a partial evaluation framework for functional logic programs has been proposed.

Abstract not found

Abstract. Well-quasi orders in general, and homeomorphic embedding in particular, have gained popularity to ensure the termination of techniques for program analysis, specialisation, transformation, and verification. In this paper we survey and discuss this use of homeomorphic embedding and clarify the advantages of such an approach over one using well-founded orders. We also discuss various extensions of the homeomorphic embedding relation. We conclude with a study of homeomorphic embedding in the context of metaprogramming, presenting some new (positive and negative) results and open problems.

Functional logic languages combine the operational principles of the most important declarative programming paradigms, namely functional and logic programming. Inductively sequential programs admit the definition of optimal computation strategies and are the basis of several recent (lazy) functional logic languages. In this paper, we define a partial evaluator for inductively sequential functional logic programs. We prove strong correctness of this partial evaluator and show that the nice properties of inductively sequential programs carry over to the specialization process and the specialized programs. In particular, the structure of the programs is preserved by the specialization process. This is in contrast to other partial evaluation methods for functional logic programs which can destroy the original program structure. Finally, we present some experiments which highlight the practical advantages of our approach. 1 Introduction Functional logic languages combine the operational p...

Functional logic languages with a complete operational semantics are based on narrowing, a unification-based goal-solving mechanism which subsumes the reduction principle of functional languages and the resolution principle of logic languages. Needed narrowing is an optimal narrowing strategy and the basis of several recent functional logic languages. In this paper, we define a partial evaluator for functional logic programs based on needed narrowing. We prove strong correctness of this partial evaluator and show that the nice properties of needed narrowing carry over to the specialization process and the specialized programs. In particular, the structure of the specialized programs provides for the application of optimal evaluation strategies. This is in contrast to other partial evaluation methods for functional logic programs which can change the original program structure in a negative way. Finally, we present some experiments which highlight the practical advantages of our approach.

Indy Indy Indy 1 Introduction innermost lazy M. Alpuente M. Falaschi G. Vidal March 4, 1998 Experiments with the Call-by-Value Partial Evaluator polyvariant polygenetic local global closedness unfolding abstraction This work has been partially supported by CICYT under grant TIC 95-0433-C03-03 and by HCM project CONSOLE. DSIC, U. P. Valencia, Camino de Vera s/n, 46022 Valencia, Spain ( alpuente,gvidal @dsic.upv.es). Dip. Matematica e Informatica, U. Udine, Via delle Scienze 206, 33100 Udine, Italy (falaschi@dimi.uniud.it). This paper summarizes our experience gained using the system, a narrowing-driven partial evaluator for functional logic programs which combines in a useful and effective way the propagation of partial data structures, by means of logical variables and unification, with better opportunities for optimization thanks the functional dimension. allows the user to select either a call-by-value ( , eager) or a call-by-name (outside-in, ) narrowing strategy to construct lo...

Languages that integrate functional and logic programming with a complete operational semantics are based on narrowing, a unification-based goal-solving mechanism which subsumes the reduction principle of functional languages and the resolution principle of logic languages. In this article, we present a partial evaluation scheme for functional logic languages based on an automatic unfolding algorithm which builds narrowing trees. The method is formalized within the theoretical framework established by Lloyd and Shepherdson for the partial deduction of logic programs, which we have generalized for dealing with functional computations. A generic specialization algorithm is proposed which does not depend on the eager or lazy nature of the narrower being used. To the best of our knowledge, this is the first generic algorithm for the specialization of functional logic programs. We study the semantic properties of the transformation and the conditions under which the technique terminates, is...

. Functional logic languages with a complete operational semantics are based on narrowing, which combines the instantiation of variables with the reduction of expressions. In this paper, we investigate the relationship between partial evaluation and more general transformations based on folding/unfolding. First, we show that the transformations obtained by partial evaluators can be also achieved by folding/unfolding using a particular kind of eurekas which can be mechanically attained. Then, we propose an algorithm (based on folding/unfolding) which starts with the automatic eureka generation and is able to perform program composition, i.e., it is able to produce a single function definition for some nested functions of the original program. This avoids the construction of intermediate data structures that are produced by the inner function and consumed as inputs by the outer function. As opposed to both partial evaluation and (general) fold/unfold transformations, strong ...