Re: Parser Cruft in gram.y

On 12/18/12 5:10 PM, Robert Haas wrote:
> I can't help but suspect that the way we handle keywords today is
> monumentally inefficient.  The unreserved_keyword products, et al,
> just seem somehow badly wrong-headed.  We take the trouble to
> distinguish all of those cases so that we an turn around and not
> distinguish them.  I feel like there ought to be some way to use lexer
> states to handle this - if we're in a context where an unreserved
> keyword will be treated as an IDENT, then have the lexer return IDENT
> when it sees an unreserved keyword.

The problem would be the lookahead.  You need to know the next token
before you can decide what context the current one is in.