[ufo]

One problem is that it is full of shift-reduce conflicts, due to a lack of an "end" token in most expressions.

The one that bugs me the most is nested match expressions, which often need to be wrapped in parenthesis.

[cyrus_]

In OCaml's expression syntax, "begin" is a synonym for left parenthesis, and "end" is a synonym for right parenthesis. So I've taken to just using "begin match e with ... end" in every situation to avoid this problem.