GLR Parser

A GLR parser, or generalized left-to-right rightmost derivation parser, is an extension of the LR parser algorithm that can handle non-deterministic and ambiguous grammars. Its theoretical foundation was given in a 1974 paper by Bernard Lang, and the first actual implementation was described in a 1984 paper by Masaru Tomita, whose goal was to parse natural language text thoroughly and efficiently, something standard LR and LL parsers cannot accommodate because they cannot handle the nondeterministic and ambiguous nature of natural language.