Re: What IS an LL/LR/SLR/LALR etc. grammar?

LL,LR,SLR and LALR are parsing methods. If a grammar can be parsed by
that method, it is also called LL,LR,SLR or LALR (k).


LL(k) means a top-down parser can be created for the parser with a max
lookahead of k symbols.
LR(k) means a bottom-up parser can be created for the parser with a max
lookahead of k symbols.




LALR(1) grammars are a subset of LR(1) grammars, requiring smaller
parsing table. (speed up gain vs. complication of error reporting and
recovery).


SLR(1) parsing is a hack of LR(0) parsing: you attempt to construct a
LR(0) parser for it, and if there are only minor glitches, you slap on
some extra control.


Because these parsing processes are rather complex, it's a lot of work
to check if a grammar is LR(k),SLR(1) or LALR(1)




Theory and Practice of Compiler Writing, by Tremblay and Sorenson,
McGraw Hill, is an in-depth work, but not for the technically
challenged.




JPA

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