A Framework for Point-Free Program Transformation

Cunha, Alcino; Pinto, Jorge Sousa; Proença, José

doi:10.1007/11964681_1

Cited by 11 publications

(14 citation statements)

References 13 publications

(11 reference statements)

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“…The most fundamental combinators are the composition of f : B → C after g : A → B , denoted by f • g : A → C , and the identity function, denoted by id : A → A. The projections π 1 : A × B → A and π 2 : A × B → B project out the left and right components of a pair, respectively, and the split [5,17,22,11].…”

Section: Point-free Combinators As Lensesmentioning

confidence: 99%

Generic Point-free Lenses

Pacheco

Cunha

2010

Lecture Notes in Computer Science

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Abstract. Lenses are one the most popular approaches to define bidirectional transformations between data models. A bidirectional transformation with view-update, denoted a lens, encompasses the definition of a forward transformation projecting concrete models into abstract views, together with a backward transformation instructing how to translate an abstract view to an update over concrete models. In this paper we show that most of the standard point-free combinators can be lifted to lenses with suitable backward semantics, allowing us to use the point-free style to define powerful bidirectional transformations by composition. We also demonstrate how to define generic lenses over arbitrary inductive data types by lifting standard recursion patterns, like folds or unfolds. To exemplify the power of this approach, we "lensify" some standard functions over naturals and lists, which are tricky to define directly "by-hand" using explicit recursion.

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Section: Point-free Combinators As Lensesmentioning

confidence: 99%

Generic Point-free Lenses

Pacheco

Cunha

2010

Lecture Notes in Computer Science

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“…Others have adopted, complemented, and extended this so-called point-free style of programming [23,16], and a summary is shown in Figure 6. The most fundamental combinators of point-free programming Primitive combinators id : A→A 6.…”

Section: Point-free Program Transformationmentioning

confidence: 99%

“…Summary of point-free program transformation. For a complete account, the reader is referred to Cunha et al [16].…”

Section: Point-free Program Transformationmentioning

confidence: 99%

“…Cunha et al [17] presented a rewriting system for simplifying point-free expressions, which was used to optimize expressions resulting from a program transformation tool that translates pointwise Haskell code into point-free style. The main improvement of our approach is typing: we can use type representations to guide the rewriting process and rewrite rules are guaranteed to be type-safe.…”

Section: Program Transformation In Calculational Formmentioning

confidence: 99%

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Coupled Transformation of Schemas, Documents, Queries, and Constraints

Visser

2008

Electronic Notes in Theoretical Computer Science

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Coupled transformation occurs when multiple software artifacts must be transformed in such a way that they remain consistent with each other. For instance, when a database schema is adapted in the context of system maintenance, the persistent data residing in the system's database needs to be migrated to conform to the adapted schema. Also, queries embedded in the application code and any declared referential constraints must be adapted to take the schema changes into account. As another example, in XML-to-relational data mapping, a hierarchical XML Schema is mapped to a relational SQL schema with appropriate referential constraints, and the XML documents and queries are converted into relational data and relational queries. The 2LT project is aimed at providing a formal basis for coupled transformation. This formal basis is found in data refinement theory, point-free program calculation, and strategic term rewriting. We formalize the coupled transformation of a data type by an algebra of information-preserving data refinement steps, each witnessed by appropriate data conversion functions. Refinement steps are modeled by so-called twolevel rewrite rules on type expressions that synthesize conversion functions between redex and reduct while rewriting. Strategy combinators are used to composed two-level rewrite rules into complete rewrite systems. Point-free program calculation is applied to optimized synthesize conversion function, to migrate queries, and to normalize data type constraints. In this paper, we provide an overview of the challenges met by the 2LT project and we give a sketch of the solutions offered.

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“…This "variable-free" philosophy has prosperred somewhat however, and developed into richer languages to facilitate programming -an early example of which is FP (Backus 1978). This has also spurred a style of programming called point-free programming (Cunha 2005). The language we have in mind however is not restricted to applicative terms alone, and therefore variables must feature in the object language.…”

Section: Substitutionmentioning

confidence: 99%