On the (non-) relationship between SLR(1) and NQLALR(1) grammars

Authors:
Manuel E. Bermudez;Karl M. Schimpf
Affiliations:
Univ. of Florida, Gainesville;Univ. of California, Santa Cruz
Venue:
ACM Transactions on Programming Languages and Systems (TOPLAS)
Year:
1988

Citing 3
Cited 0

Methods for Computing LALR(k) Lookahead

ACM Transactions on Programming Languages and Systems (TOPLAS)
Efficient Computation of LALR(1) Look-Ahead Sets

ACM Transactions on Programming Languages and Systems (TOPLAS)
Simple LR(k) grammars

Communications of the ACM

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Abstract

A popular but “not-quite” correct technique for computing LALR(1) look-ahead sets has been formalized by DeRemer and Pennello and dubbed NQLALR(l). They also claim that the class of SLR(l) grammars is a subset of the class of NQLALR(1) grammars. We prove here that no such relationship exists between those two classes. We do so with a counterexample that, ironically, appeared in DeRemer and Pennello's own paper.