Re: How to solve this kind of ambiguities?

[Sylvain Schmitz]

Dong Tiger wrote:
> Look at the following expression( c-like syntax):
>
>       1 - 2 * (TYPE_OR_VAR) - 1
>
> The real token type of TYPE_OR_VAR is unknown. The expression could be
> parsed as the following two options:
>
> 1. TYPE_OR_VAR is a typename. Then "(TYPE_OR_VAR)-1" is a cast expression.
> And the expression equals to:
>      1 - ( 2 * ( (TYPE_OR_VAR)-1))
>
> 2. TYPE_OR_VAR is a variable. Then the expression equals to:
>      1 - 2 * TYPE_OR_VAR - 1
>
> I would like to choose the second option but I can't do it with 
> "%dprec". As
> when the ambiguity happens, the two options
> are shifted by the same rule.
>
> What can I do to get around this problem?

Your lexer could lookup your symbol table and return TYPE in one case 
and VAR in the other.

--
  Sylvain