Re: ambiguity of grammar and LR(k)

Linlist Leo <linlist@fudan.edu> schreef
> It is well-known the following grammar is ambiguous so that it is
> not LR(k) for any k.
> S -> iEtSeS | iEtS | a
> ('a' is not important, maybe just some assigning statement)
>
> But it can be written in an umambiguous way. I devised the following
> grammar(maybe incorrect).
> S -> M | U
> M -> iEtMeM | a
> U -> iEtS
>
> I guess it LR(1). Any correction will be welcomed.


I have a book "The UNIX programming environment" written by Brian
Kernighan and Rob Pike (but it is written in Dutch). It proposes the
following:


stmt : if cond stmt end
                | if cond stmt end ELSE stmt end ;


if : IF ;


cond : '(' expr ')' ;


end : ;


I have to test it yet.
--
Hans Kamp
[K and P's book is also available in English. -John]

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