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Specialization of Inductively Sequential Functional Logic Programs
, 1999
"... 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 ..."
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Cited by 21 (11 self)
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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...
Improving Control in Functional Logic Program Specialization
, 1998
"... We have recently defined a framework for Narrowingdriven Partial Evaluation (NPE) of functional logic programs. This method is as powerful as partial deduction of logic programs and positive supercompilation of functional programs. Although it is possible to treat complex terms containing primitive ..."
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Cited by 18 (12 self)
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We have recently defined a framework for Narrowingdriven Partial Evaluation (NPE) of functional logic programs. This method is as powerful as partial deduction of logic programs and positive supercompilation of functional programs. Although it is possible to treat complex terms containing primitive functions (e.g. conjunctions or equations) in the NPE framework, its basic control mechanisms do not allow for effective polygenetic specialization of these complex expressions. We introduce a sophisticated unfolding rule endowed with a dynamic narrowing strategy which permits flexible scheduling of the elements (in conjunctions) which are reduced during specialization. We also present a novel abstraction operator which carefully considers primitive functions and is the key to achieving accurate polygenetic specialization. The abstraction operator extends some recent partitioning techniques defined in the framework of conjunctive partial deduction. We provide experimental results obtained from an implementation using the INDY system which demonstrate that the control refinements produce better specializations.
Specialization of Functional Logic Programs Based on Needed Narrowing
 Proc. of ICFP'99
, 1999
"... Functional logic languages with a complete operational semantics are based on narrowing, a unificationbased goalsolving mechanism which subsumes the reduction principle of functional languages and the resolution principle of logic languages. Needed narrowing is an optimal narrowing strategy and th ..."
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Cited by 15 (9 self)
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Functional logic languages with a complete operational semantics are based on narrowing, a unificationbased goalsolving 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.
Natural narrowing for general term rewriting systems
 Proc. of 16th International Conference on Rewriting Techniques and Applications, RTA’05, Lecture Notes in Computer Science
, 2005
"... Abstract. For narrowing to be an efficient evaluation mechanism, several lazy narrowing strategies have been proposed, although typically for the restricted case of leftlinear constructor systems. These assumptions, while reasonable for functional programming applications, are too restrictive for a ..."
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Cited by 8 (5 self)
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Abstract. For narrowing to be an efficient evaluation mechanism, several lazy narrowing strategies have been proposed, although typically for the restricted case of leftlinear constructor systems. These assumptions, while reasonable for functional programming applications, are too restrictive for a much broader range of applications to which narrowing can be fruitfully applied, including applications where rules have a nonequational meaning either as transitions in a concurrent system or as inferences in a logical system. In this paper, we propose an efficient lazy narrowing strategy called natural narrowing which can be applied to general term rewriting systems with no restrictions whatsoever. An important consequence of this generalization is the wide range of applications that can now be efficiently supported by narrowing. We highlight a few such applications including symbolic model checking, theorem proving, programming languages, and partial evaluation. What thus emerges is a general and efficient unified mechanism based on narrowing, that seamlessly integrates a very wide range of applications in programming and proving. 1
Experiments with the CallbyValue Partial Evaluator
, 1998
"... Indy Indy Indy 1 Introduction innermost lazy M. Alpuente M. Falaschi G. Vidal March 4, 1998 Experiments with the CallbyValue Partial Evaluator polyvariant polygenetic local global closedness unfolding abstraction This work has been partially supported by CICYT under grant TIC 950433C0303 and ..."
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Cited by 3 (3 self)
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Indy Indy Indy 1 Introduction innermost lazy M. Alpuente M. Falaschi G. Vidal March 4, 1998 Experiments with the CallbyValue Partial Evaluator polyvariant polygenetic local global closedness unfolding abstraction This work has been partially supported by CICYT under grant TIC 950433C0303 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 narrowingdriven 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 callbyvalue ( , eager) or a callbyname (outsidein, ) narrowing strategy to construct lo...
UPVCurry: An Incremental Curry Interpreter
, 1999
"... . Functional logic programming integrates the best features of modern functional and logic languages. The multiparadigm declarative language Curry is an extension of Haskell which is intended to become a standard in the area. In this paper, we present UPVCurry, an efficient and quite complete impl ..."
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Cited by 3 (2 self)
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. Functional logic programming integrates the best features of modern functional and logic languages. The multiparadigm declarative language Curry is an extension of Haskell which is intended to become a standard in the area. In this paper, we present UPVCurry, an efficient and quite complete implementation of Curry based on a new, incremental definition of its basic evaluation mechanism. We compare UPVCurry with already existing implementations of other Curry interpreters. Keywords: Curry, Functional logic languages, Implementation. 1 Introduction Functional logic languages combine the best features of the most important declarative programming paradigms, namely functional and logic programming (see [Han94] for a survey). Throughout this decade, many practical proposals have been made to amalgamate functional and logic programming languages. However, these languages have not succeeded in becoming widely used by the functional or logic programming communities. The multiparadigm l...
Specialization of Functional Logic Programs
"... Languages that integrate functional and logic programming with a complete operational semantics are based on narrowing, a unificationbased goalsolving mechanism which subsumes the reduction principle of functional languages and the resolution principle of logic languages. In this article, we prese ..."
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Cited by 2 (2 self)
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Languages that integrate functional and logic programming with a complete operational semantics are based on narrowing, a unificationbased goalsolving 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...
Natural narrowing as a general unified mechanism for programming and proving
, 2004
"... Abstract. For narrowing to be an efficient evaluation mechanism, several lazy narrowing strategies have been proposed, although typically for the restricted case of leftlinear constructor systems. These assumptions, while reasonable for functional programming applications, are too restrictive for a ..."
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Cited by 2 (2 self)
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Abstract. For narrowing to be an efficient evaluation mechanism, several lazy narrowing strategies have been proposed, although typically for the restricted case of leftlinear constructor systems. These assumptions, while reasonable for functional programming applications, are too restrictive for a much broader range of applications to which narrowing can be fruitfully applied, including applications where rules have a nonequational meaning either as transitions in a concurrent system or as inferences in a logical system. In this paper, we propose an efficient lazy narrowing strategy called natural narrowing which can be applied to general term rewriting systems with no restrictions whatsoever. An important consequence of this generalization is the wide range of applications that can now be efficiently supported by narrowing. We highlight a few such applications including symbolic model checking, theorem proving, programming languages, and partial evaluation. What thus emerges is a general and efficient unified mechanism based on narrowing, that seamlessly integrates a very wide range of applications in programming and proving. 1
Natural Narrowing for General Term Rewriting Systems
"... 1 Introduction Rewriting is currently recognized as a very general declarative formalism to specify,program, and reason about computational systems. The more traditional applications have been in the context of equational reasoning and of equational/functional programming, where the rewriting relat ..."
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1 Introduction Rewriting is currently recognized as a very general declarative formalism to specify,program, and reason about computational systems. The more traditional applications have been in the context of equational reasoning and of equational/functional programming, where the rewriting relation is understood as oriented equality. But there is an increasing awareness of the usefulness of rewriting in nonequational contexts, wherea rewrite is understood as a transition or an inference: for example to specify and program concurrent systems or logical inference systems. This has led, for example,to theoretical developments such as rewriting logic [33], and to the development of language implementations supporting nonequational rewriting such as ELAN [8] and Maude [9].A similar widening of the scope is needed for narrowing, which generalizes rewriting
Redundancy Analyses in Term Rewriting (Extended Abstract)
, 2000
"... The uncontrolled application of automatic transformation processes during the formal development and optimization of programs can introduce encumbrances in the generated code that programmers usually (or presumably) do not write. An example is the introduction of redundant arguments in the functions ..."
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The uncontrolled application of automatic transformation processes during the formal development and optimization of programs can introduce encumbrances in the generated code that programmers usually (or presumably) do not write. An example is the introduction of redundant arguments in the functions defined in the program. Redundancy of a parameter means that replacing it by any value does not change the result since the value is not used. In this work, we give a theoretical foundation for the analysis and elimination of redundant arguments in term rewriting systems as a model for the programs that can be written in more sophisticated declarative languages. The framework is independent from both the considered semantics and the framework  operational or denotational which is used to describe (and approximate) the observed meaning. We particularize our method to the standard (reduction) semantics of term rewriting systems including the standard normalization semantics ...