Jacques Loeck

An algorithm is described which accepts an arbitrary context-free grammar and constructs a bounded-context parser for it whenever such a parser exists. In the first part of the paper the definition of a context-free grammar and the working of a bounded-context parser are recalled. The notion of reduction class for a context-free grammar is then introduced and its connection with the structure of a bounded-context parser is indicated. Next, pushdown automata which generate the different reduction classes of a context-free grammar are defined. Finally, the algorithm is described; it essentially carries out an exhaustive study of all possible runs of the pushdown automata generating the reduction classes. In the second part, the utility of the algorithm is discussed in the light of the experience gained from its use in compiler design. The algorithm is claimed to be particularly useful in the simultaneous design of a language and a compiler for it.