On the optimality of change propagation for incremental evaluation of hierarchical attribute grammars

Abstract

Several new attribute grammar dialects have recently been developed, all with the common goal of allowing large, complex language translators to be specified through a modular composition of smaller attribute grammars. We refer to the class of dialects as hierarchical attribute grammars. In this short article, we present a characterization of optimal incremental evaluation that indicates the unsuitability of change propagation as the basis of an optimal incremental evaluator for hierarchical attribute grammars. This result lends strong support to the use of incremental evaluators based on more applicative approaches to attribute evaluation, such as Carle and Pollock's evaluator based on caching of partially attributed subtrees, Pugh's evaluator based on function caching of semantic functions, and Swierstra and Vogt's evaluator based on function caching of visit sequences.

Specification and dialogue control of visual interaction through visual rewriting systems

“…To this end, it extends the use of attributed rewriting systems as employed in the construction of compilers, to the definition of Visual Conditional Attributed Rewriting systems. In particular, the avoidance of nonterminal symbols facilitates an incremental and modular construction of the meaning of the sentence, without the need to introduce in the rewriting system explicit constructs to indicate hierarchies or modularity, as is typical of the class of Hierarchical Attribute Grammars [Carle and Pollock 1996]. Modularity and hierarchies, where necessary, can be managed by extending the domain of attributes to refer to visual sentences.…”