A Deterministic Attribute Grammar Evaluator Based on Dynamic Scheduling

Abstract

The problem of semantic evaluation in a compiler-generating system can be addressed by specifying language semantics in an attribute grammar [19], a context-free grammar augmented with “attributes” for the nonterminals and “semantic functions” to compute the attributes. A deterministic method for evaluating all attributes in a “semantic” parse tree is derived and shown to have time and space complexities which are essentially linear in the size of the tree. In a prepass through the parse tree, the method determines an evaluation sequence for the attributes; thus it is somewhat analogous to dynamic programming. The constructor-evaluator system described should be suitable for inclusion in a general translator-writing system.