Gilles Roussel

Dynamic Attribute Grammars

Although Attribute Grammars were introduced long ago, their lack of expressiveness has resulted in limited use outside the domain of static language processing. With the new notion of Dynamic Attribute Grammars defined on top of Grammar Couples, we show that it is possible to extend this expressiveness and to describe computations on structures that are not just trees, but also on abstractions allowing for infinite structures. The result is a language that is comparable in power to most first-order functional languages, with a distinctive declarative character.

Specification and Implementation of Grammar Couplings using Attribute Grammars

This paper introduces the notion of a coupling of two grammars, defined by associations between their non-terminals and terminals. We present an algorithm for automatically producing, from these associations, an attribute grammar which specifies the translation from one grammar to the other.

Attribute Grammars and Functional Programming Deforestation

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 speciications. We argue that one of the original concepts of Attribute Grammars is precisely to make data structures explicit in program speciications. 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 rst make a simple comparison: purely-synthesized Attribute Grammars and rst 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 hy-lomorphism 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.

Coupling Evaluators for Attribute Coupled Grammars

Some years ago, the notion of attribute coupled grammars was introduced by Ganzinger and Giegerich [4], together with descriptional composition. The latter works essentially at the specification level, i.e., it produces an attribute grammar which specifies the composition of two attribute coupled grammars.