LL and LR Translators Need k > 1 Lookahead

Abstract

Language translation is a harder and more important problem than language recognition. In particular, programmers implement translators not recognizers. Yet too often, translation is equated with the simpler task of syntactic parsing. This misconception coupled with computing limitations of past computers has led to the almost exclusive use of LA(1) and LL(1) in parser generators. We claim that use of k > 1 lookahead can and should be available in practice, as it simplifies the translator development. We give several examples justifying our arguments.