On Fri, 27 Oct 2006 [EMAIL PROTECTED] wrote: > > Then again, I try to > > avoid mid-rules, $0, and $-n, so maybe I don't have the right feel for > > this. > maybe disable the check completely if $0 or $-n is used.
That's an interesting possibility. However, I worry that there are cases where that produces unexpected results for the user. For example, imagine a grammar that uses $0 in a single rule that perhaps has absolutely no direct or indirect association with any mid-rules. Bison would then fail to warn about mid-rules everywhere even when the user is expecting them. The user who has grown accustomed to these warnings would then have a false sense of security as he probably would not guess that $0 disabled the warnings. I'd rather choose a global default (mid-rule warnings on or off) and then let the user specify otherwise either globally (-W) or case-by-case (USE). > What is the impact of the unused $n ? I believe our original motivation to implement all these set/unset value warnings was to help users avoid memory leaks. This can be relevant with mid-rule values. However, in the specific case of mid-rule values, we felt that it's usually a mistake anyway when a user sets $$ an doesn't use $n. Is that what you're asking? > And also since bison are LALR(1) the restriction of checking by looking just > one level ahead is not that far off. I don't see a connection between one level down and one token of lookahead. Did I misunderstand you? _______________________________________________ help-bison@gnu.org http://lists.gnu.org/mailman/listinfo/help-bison
