SL PARSES THE LR LANGUAGES

SL, the Syntax Language component of S/SL (Syntax/Semantic Language) is a dataless programming language for implementing efficient recursive descent parsers. SL is clearly powerful enough to parse the LL(1) languages, but it is much less obvious that it is sufficiently powerful to parse the LR(κ) languages. We show that this is in fact the case by giving an algorithm to construct an SL program that parses the same language as a given LR(1) parser. This construction provides both a proof that SL has the parsing power of LR(1) [and hence LR(κ)] and a practical method for deriving efficient SL parsers from BNF grammars.