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open Expr12
open Expr13
open Expr13double
let const k = E (EConst k)
let add e1 e2 = E (EAdd (e1, e2))
let rec eval (E e) =
match e with
| EConst k -> k
| EAdd (e1, e2) -> eval e1 + eval e2
let e : expr =
add (const 1) (const 2)
let () =
(* should print: 3 then 6 *)
Printf.printf "%d\n%d\n%!" (eval e) (eval (double e))
let omap : 'expr1 'expr2 . ('expr1 -> 'expr2) -> 'expr1 oexpr -> 'expr2 oexpr =
fun f e ->
let v = object
inherit [_] omap
method visit_'expr _env e = f e
end in
v # visit_oexpr () e
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