type t = exp
+(* For printing error messages *)
+let op_show op =
+ match op with
+ | PlusOp -> "+"
+ | MinusOp -> "-"
+ | TimesOp -> "*"
+ | DivideOp -> "/"
+ | EqOp -> "="
+ | NeqOp -> "<>"
+ | LtOp -> "<"
+ | LeOp -> "<="
+ | GtOp -> ">"
+ | GeOp -> ">="
+
+(* For printing AST *)
let op_to_string op =
match op with
| PlusOp -> "PlusOp"