On Wed, Sep 25, 2013 at 2:14 AM, Konrad Hinsen <konrad.hin...@fastmail.net> wrote: > > > Maybe making the error message more specific like "Did you forget to > (require > > (for-syntax syntax/parse)) ?" ? Or is it too specific? > > It would already help a lot if the error message said something about > syntax-parse being undefined. But it complains about the pattern, > which is kind of strange. It looks like syntax-parse is already there > but incomplete.
The reason it complains about the pattern is that `_` is already bound -- `syntax-rules` and `syntax-case` both work at phase 0 without any new requires. So Racket interprets everything as function application until it gets to the `_`, which it tries to expand and gives an error because it's not supposed to be used as an expression. Of course, you didn't mean it as an expression, but as part of a `syntax-parse` pattern, but because `syntax-parse` wasn't bound, it didn't get recognized as a pattern. I think the error message could be better about making this clearer, but I can't think of a good way that doesn't build-in `syntax/parse`. Sam ____________________ Racket Users list: http://lists.racket-lang.org/users
