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| structure Plus = struct | |
| datatype 'a t = T of 'a -> 'a -> 'a | |
| end | |
| structure Mul = struct | |
| datatype 'a t = T of 'a -> 'a -> 'a | |
| end | |
| structure FromInt = struct | |
| datatype 'a t = T of int -> 'a | |
| end | |
| fun uses_dict (Plus.T plus, Mul.T mul, FromInt.T from_num) = | |
| let val z = from_num 15 | |
| fun compiled x y = mul (plus x y) z | |
| in compiled end | |
| fun uses_dict2 (Plus.T plus, FromInt.T fromInt) = | |
| let val z = fromInt 15 | |
| fun compiled x = plus x z | |
| in compiled end | |
| fun uses_dict3 (plus, mul, fromNum as FromInt.T frN) = | |
| let | |
| val f = uses_dict (plus, mul, fromNum) | |
| val g = uses_dict2 (plus, fromNum) | |
| val z = frN 5 | |
| fun compiled x = f (g x) z | |
| in | |
| compiled | |
| end | |
| local fun curry f x y = f(x,y) in | |
| structure Int_ = | |
| struct | |
| val plus = Plus.T (curry Int.+) | |
| val mul = Mul.T (curry Int.*) | |
| val fromInt = FromInt.T (fn x => x) | |
| end | |
| structure Real_ = | |
| struct | |
| val plus = Plus.T (curry Real.+) | |
| val mul = Mul.T (curry Real.*) | |
| val fromInt = FromInt.T Real.fromInt | |
| end | |
| end | |
| local open Int_ in | |
| val _ = uses_dict (plus, mul, fromInt) 5 6 | |
| val _ = uses_dict2 (plus, fromInt) 5 | |
| end | |
| local open Real_ in | |
| val _ = uses_dict (plus, mul, fromInt) 5.0 6.0 | |
| val _ = uses_dict2 (plus, fromInt) 5.0 | |
| end |
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