[wg-camlp4] [Caml-list] Working Group: the future of syntax extensions in OCaml, after camlp4

[DooMeeR]

> Assuming it is indeed technically possible, do you think it would be a
> good idea to merge the syntactic categories of patterns and expressions?

Not only would it be useful for -ppx, it would probably help to produce 
better error messages as well. A message like "you cannot use { f = …; _ 
} in expressions, this is only for patterns" is a bit better than "parse 
error"…

Not that we cannot do that already with additional rules in the parser, 
but after a merge, the type-checker would kind of be forced to handle 
these cases. (Unless it uses a catch-all.)

Cheers,

-- 
Romain Bardou