[antlr-interest] Proposal: synpred inversion?
Terence Parr
parrt at cs.usfca.edu
Sat Mar 21 12:25:59 PDT 2009
On Mar 21, 2009, at 12:24 PM, Sam Harwell wrote:
> Currently you can only invert sets in a synpred. It seems like
> inverting the entire predicate could be useful. It could be
> implemented by backtracking returning state.failed instead of !
> state.failed, though putting it in the dfa could be a bit tougher
> (but doable).
>
> I’m particularly interested in an example of how this could
> encourage poor grammar design, as that would be a big fault with the
> idea.
PEGs have not-grammar-fragment but they are mostly useful in lexer.
Ter
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