A bounded graph-connect construction for LR-regular parsers

Abstract

Parser generation tools currently used for computer language analysis rely on user wisdom in order to resolve grammar conflicts. Here practical LR(0)-based parser generation is introduced, with automatic conflict resolution by potentially-unbounded lookahead exploration. The underlying LR(0)-automaton item dependence graph is used for lookahead DFA construction. A bounded graph-connect technique overcomes the difficulties of previous approaches with empty rules, and compact coding allows to precisely resume right-hand contexts. Resulting parsers are deterministic and linear, and accept a large class of LR-regular grammars including LALR(fc). Their construction is formally introduced, shown to be decidable, and illustrated by a detailed example.