|LR (k) vs. LALR email@example.com (Profetas) (2004-08-09)|
|Re: LR (k) vs. LALR firstname.lastname@example.org (Tim Bauer) (2004-08-10)|
|Re: LR (k) vs. LALR Colin_Paul_Gloster@ACM.org (Colin Paul Gloster) (2004-08-10)|
|Re: LR (k) vs. LALR email@example.com (Jean-Marc Bourguet) (2004-08-11)|
|Re: LR (k) vs. LALR firstname.lastname@example.org (2004-08-15)|
|Re: LR (k) vs. LALR email@example.com (Clint Olsen) (2004-08-23)|
|Re: LR (k) vs. LALR firstname.lastname@example.org (Jeremy Wright) (2004-08-25)|
|Re: LR (k) vs. LALR email@example.com (Sylvain Schmitz) (2004-09-03)|
|Re: LR (k) vs. LALR firstname.lastname@example.org (2004-09-03)|
|Re: LR (k) vs. LALR email@example.com (Sean Case) (2004-09-07)|
|Re: LR (k) vs. LALR cfc@shell01.TheWorld.com (Chris F Clark) (2004-09-07)|
|From:||Sylvain Schmitz <firstname.lastname@example.org>|
|Date:||3 Sep 2004 12:31:20 -0400|
|References:||04-08-037 04-08-055 04-08-073 04-08-098|
|Posted-Date:||03 Sep 2004 12:31:20 EDT|
Kamal R. Prasad wrote:
> Jean-Marc Bourguet <email@example.com> wrote
>>Every language for which a LR(1) grammar LR(1) exists has also an
>>LALR(1) grammar. (Search for the archive of this group, I started a
>>thread on the subject).
> The BNF remains the same as in LR(1), but the number of parser states
> is reduced in an LALR(1) parser. Either Im making a mistake or the
> text above is misleading to indicate that the grammar needs to be
> changed when moving from Lr(1) to LALR(1).
> [The moderator may want to filter out erroneous statements].
The class of LALR(1) grammars is a proper subset of the class of LR(1)
grammars, so yes, once you have obtained a LR(1) grammar for your
language, you might have to modify your grammar a bit further to make it
LALR(1). This generally involves introducing new rules to avoid some
state merges done by the LR(0) automaton which underlies the LALR(1) parser.
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