Extended context-free grammars (also called regular right part grammars) allow for compact and readable descriptions of the syntax of programming languages. Recursion in conventional context-free grammars can in most cases be replaced by iteration. Parser tables of predictive LL-parsers for extended grammars can be generated very efficiently if the length of look-ahead is 1. The generation time is proportional to the size of the parser table, that is the product of grammar size and number of terminal symbols.
Reinhold Heckmann / heckmann@absint.com