Re: advice needed re: parsing C decl syntax

Paul Tarvydas writes:
>I'm still reluctant to use a straight LALR table parser for reasons of
>(ahem) efficiency. Things like expressions & statements are wonderful
>candidates for recursive-descent.
> ...
>Has anybody successfully married LR parsing with recursive-descent
>techniques? Are there any other clean tricks/techniques I could use?


At the most recent Compiler Construction Conference (SigPlan notices,
July 1986), Thomas Pennello presented a technique for "compiling" the
parse-tables directly into (assembly) code, which apparently speeds up
the parsing process by a factor of 6-10.


>[But I really don't see the point. Yacc certainly has its problems, but
>excessively slow parsing has never seemed to be one of them. -John]


In his conclusions, Pennello also echoes this opinion:
        "Trying to speed up an LR parser may seem like beating as dead
        horse, since LR parsers are already reasonably fast."


Still, I think the paper is worth reading.


Steve Vegdahl
Computer Research Lab
Tektronix Labs
Beaverton, Oregon

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