Can this grammar be modified for lookahead of 1 ?

rahul@lsil.com (Rahul Bhargava x4596 ) writes:


> I am trying to generate a parser using yacc for the following grammar:
>
> s -> l (1)
> l -> L i F i e (2)
> i -> A | ACA | CA | AC | C (3)
> e -> C (4)


When you are in state "i", consumed an "A" and have "C" as a lookahead,
it is ambiguous because you don't know whether to reduce the "I" state or
shift the "C". YACC resolves shift-reduce conflicts by shifting.


Therefore, it cannot parse the following string although it is acceptable.


        "LAFAC"


To resolve this, you may wish to try the following:


s -> l (1)
l -> L i F ie (2)
i -> A | ACA | CA | AC | C (3)
ie -> AC | ACAC | CAC | ACC | CC (4)


Create a new production which is the concatenation of the "i" & "e"
productions.


Thank you.


Steve Simmons
--

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