| trans_exp env vartypes (A.ConstExp c) = T.CONST(c)
| trans_exp env vartypes (A.StringExp s) = T.STRING(Stringref.new s)
| trans_exp env vartypes (A.OpExp(oper, [e1, e2])) =
| trans_exp env vartypes (A.ConstExp c) = T.CONST(c)
| trans_exp env vartypes (A.StringExp s) = T.STRING(Stringref.new s)
| trans_exp env vartypes (A.OpExp(oper, [e1, e2])) =