Search results for keyword `deforestation'

[156]

Loïc Correnson, Etienne Duris, Didier Parigot, and Gilles Roussel. Attribute grammars and functional programming deforestation. In Fourth International Static Analysis Symposium -- Poster Session, Paris, France, September 1997. (Gzipped PostScript, 16 pages, 88632 bytes)

The functional programming community is paying increasing attention to static structure-based transformations. For example, generic control operators, such as fold, have been introduced in functional programming to increase the power and applicability of a particular kind of static transformation, called deforestation, which prevents the construction of useless intermediate data structures in function composition. This is achieved by making the structure of the data more explicit in program specifications. We argue that one of the original concepts of Attribute Grammars is precisely to make data structures explicit in program specifications. Furthermore, there exists a powerful static deforestation-like transformation in their context. In this paper, we present similarities between deforestation methods, on the one hand with the functional approach, and on the other hand with the Attribute Grammars approach. In order to gain a grasp of these similarities, we first make a simple comparison: purely-synthesized Attribute Grammars and first order folds. In this context, deforestation transformations are equivalent. This allows us to highlight the limitations of the fold formalism and to present how the hylomorphism approach generalizes it; hylomorphisms and attribute grammars are surprisingly alike. Finally, we show how the inherited attribute notion in Attribute Grammars solves some transformation problems in higher order functional programs.

[159]

Loïc Correnson, Etienne Duris, Didier Parigot, and Gilles Roussel. Symbolic composition. Technical Report 3348, INRIA, January 1998. (Gzipped PostScript, 27 pages, 148776 bytes)

The deforestation of a functional program is a transformation which gets rid of intermediate data structures constructions that appear when two functions are composed. The descriptional composition, initially introduced by Ganzinger and Giegerich, is a deforestation method dedicated to the composition of two attribute grammars. This article presents a new functional deforestation technique, called symbolic composition, based on the descriptional composition mechanism, but extending it. An automatic translation from a functional program into an equivalent attribute grammar allows symbolic composition to be applied, and then the result can be translated back into a functional program. This yields a source to source functional program transformation. The resulting deforestation method provides a better deforestation than other existing functional techniques. Symbolic composition, that uses the declarative and descriptional features of attribute grammars is intrinsically more powerful than categorical-flavored transformations, whose recursion schemes are set by functors. These results tend to show that attribute grammars are a simple intermediate representation, particularly well-suited for program transformations.

[160]

Loïc Correnson, Etienne Duris, Didier Parigot, and Gilles Roussel. Generic programming by program composition (position paper). In Workshop on Generic Programming, Marstrand, Sweden, June 1998. conjunction with MPC'98. (Gzipped PostScript, 13 pages, 70933 bytes)

Recently, generic programming becomes of a major interest in several programming paradigms. A recurrent idea to achieve genericity is to abstract computations from their representative data structures. This allows these generic specifications to be instantiated onto a large number of neighboring data structures. Moreover the program can be adapted when the data structures have to evolve. Polytypic programming, adaptive programming and generic attribute grammars are generic programming methods related to this approach. Their comparison leads us to propose a common framework for generic programming: automatic generation of programs that compute morphisms between data structures, and program composition. Thanks to this compositional approach, the complete specialization of generic programs could be advantageously delegated to some powerful and general deforestation method.

[162]

Loïc Correnson, Etienne Duris, Didier Parigot, and Gilles Roussel. A generic framework for genericity. English version of, 1998. (Gzipped PostScript, 7 pages, 65289 bytes)

Recently, generic programming becomes of a major interest in several programming paradigms. A recurrent idea to achieve genericity is to specify algorithms on their convenient data structure, and to allow these specifications to be instantiated onto a large number of neighboring data structures. Polytypic programming, shapely types and generic attribute grammars are generic programming methods related to this approach. A framework for generic programming is proposed to embed these methods. It consists in tools for automatic generation of morphisms between data structures, and for program composition. Thanks to this compositional approach, the complete specialization of generic programs could be advantageously delegated to a general and powerful mechanism of ``symbolic composition'', which performs deforestation and partial evaluation.

[221]

Etienne Duris, Didier Parigot, Gilles Roussel, and Martin Jourdan. Attribute grammars and folds: Generic control operators. Rapport de recherche 2957, INRIA, August 1996. (Gzipped PostScript, 29 pages, 176512 bytes)

Generic control operators, such as fold, have been introduced in functional programming to increase the power and applicability of data-structure-based transformations. This is achieved by making the structure of the data more explicit in program specifications. We argue that this very important property is one of the original concepts of attribute grammars. In this paper, we informally show the similarities between the fold formalism and attribute grammar specifications. We also compare their respective method to eliminate the intermediate data structures introduced by function composition (notion of deforestation or fusion): the normalization algorithm for programs expressed with folds and the descriptional composition of attribute grammars. Rather than identify the best way to achieve deforestation, the main goal of this paper is merely to intuitively present two programming paradigms to each other's supporting community and provide an unbiased account of their similarities and differences, in the hope that this leads to fruitful cross-fertilization.

[224]

Etienne Duris, Didier Parigot, Gilles Roussel, and Martin Jourdan. Structure-directed genericity in functional programming and attribute grammars. Rapport de Recherche 3105, INRIA, February 1997. (Gzipped PostScript, 18 pages, 122262 bytes)

Generic control operators, such as fold, have been introduced in functional programming to increase the power and applicability of data-structure-based transformations. This is achieved by making the structure of the data more explicit in program specifications. We argue that this very important property is one of the original concepts of attribute grammars. In this paper, we present the similarities between the fold formalism and attribute grammars. In particular, we show the equivalence of their respective deforestation methods. Given these results and the fundamental role of deforestation in the concept of structure-directed genericity, first devised for attribute grammars with descriptional composition, we show how the fold operator with its fusion method allow to transport this concept in the area of functional programming.

[226]

Etienne Duris. Functional programming and attribute grammar deforestation. In Proc.of the International Conference on Functional Programming (ICFP'97) -- Poster Session, Amsterdam, The Netherlands, June 1997. ACM Press.