Top-down parsing in Coco-2

Abstract

Coco-2 [Dobler90] is a new compiler compiler with two interesting features: It allows the specification of the lexical structure, syntax and semantics of a source language within a single document and it implements a new top-down parsing method. This paper focuses on the new parsing method that conveniently incorporates the evaluation of semantic actions in table-driven top-down parsers. The new method is called hybrid because it is a powerful combination of table-driven top-down syntax analysis and the handling of semantic evaluation as implemented in recursive descent parsers. The most notable fact of this method is, that it provides the benefits of table-driven top-down parsing and recursive descent while avoiding their drawbacks.