Sheila A. Greibach

Automatic syntactic analysis has recently become important for both natural language data processing and syntax-directed compilers. A formal parsing system G = (V, &mgr;, T, R) consists of two finite disjoint vocabularies, V and T, a many-many map, &mgr;, from V onto T, and a recursive set R of strings in T called syntactic sentence classes. Every program for automatic syntactic analysis determines a formal parsing system. A directed production analyzer (I, T, X, &rgr;) is a nondeterministic pushdown-store machine with internal vocabulary I, input vocabulary T, and all productions of &rgr; in the form: (Z, a) → aY1 ··· Ym, Z, Yi &egr; I, a &egr; T. Every context-free language can be analyzed by a directed production analyzer.