[antlr-interest] grammar guessing.

Bryan Ewbank ewbank at gmail.com
Tue Apr 5 13:38:54 PDT 2005


Related to guessing mode is scanner lookahead.  I was having trouble
with scanner lookahead until I learned about semantic predicates
(thanks to Ter for his help!).  It might be appropriate here as well.

For example, if you have k>2, you can't use one token to alter the
scanner results on the next token - the token has already been
processed.

Ideally, you should be able to scan the entire file into a token
stream; with semantic predicates, you can do this.

On Apr 5, 2005 11:48 AM, Bharath Sundararaman
<Bharath.Sundararaman at starthis.com> wrote:
> I have a rule of the form: 
> 
> var: v:IDENT{Get type of "v" and store it in AST #v}(subscripts[#v])?; 
> 
> Before the 'subscripts' rule is called, I have to store the type of 'v'.
> However, the compiler is in GUESSING MODE


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