The parser doesn't know about operators and parses everything as normal
function application. This module contains the functions that parses the
operators properly. For a stand-alone implementation of this see
It also contains the function that puts parenthesis back given the precedence of the context.
Parses a left-hand side, and makes sure that it defined the expected name. TODO: check the arities of constructors. There is a possible ambiguity with postfix constructors: Assume _ * is a constructor. Then 'true *' can be parsed as either the intended _* applied to true, or as true applied to a variable *. If we check arities this problem won't appear.