Re: Moving from LR(0) to LALR(1)

> I've been able to implement a program that generates action and GOTO
> tables for a given grammar using LR(0). However, I haven't been able
> to find any good documentation (read: something simple enough I can
> understand) on switching over to LALR(1). Since my main goal for
> writing this is parsing Java, getting it to use LALR(1) is a necesity
> (or at least some equivalently powered algorithm).
>
> Are there any good online resources to describe this transition?


Well, I guess there is no 'standard way' of implementing LALR(1)
parsing algorithms in practice (of course, I am not taking about the
theoretical methods). GNU Bison is a free LALR(1) parser generator
(written in C) and so is SableCC (written in Java); I guess you can
start by studying one of these. I have tried a bit to understand Bison
code myself and found it is not that easy. However, I was able to
document the internals of the LALR(1) parser (in C) generated by GNU
Bison - http://cs.uic.edu/~spopuri/cparser.html . This article
compares the standard algorithms published in books with a real world
implementation.


Hope that helps.


satya.

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