Provide a parser to parse a type expression. Grammar:
- int , bool , ... basic types.
- Other identifiers : type variables.
- (t,u,v,...) : tuple (product) type.
- [t] : list over t.
- {t} : set over t.
- t->u : a function type from t to u.
parseInLine : string -> TypeDD.Type
It parses the input string and produces the representing value of type TypeDD.Type.