Java支持Currying吗?

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在Java中是否有任何方法支持Currying

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代码:

interface Function1<A, B> {
  public B apply(final A a);
}

interface Function2<A, B, C> {
  public C apply(final A a, final B b);
}

class Main {
  public static Function2<Integer, Integer, Integer> simpleAdd = 
    new Function2<Integer, Integer, Integer>() {
      public Integer apply(final Integer a, final Integer b) {
        return a + b;
      }
    };  

  public static Function1<Integer, Function1<Integer, Integer>> curriedAdd = 
    new Function1<Integer, Function1<Integer, Integer>>() {
      public Function1<Integer, Integer> apply(final Integer a) {
        return new Function1<Integer, Integer>() {
          public Integer apply(final Integer b) {
            return a + b;
          }
        };
      }
    };

  public static void main(String[] args) {
    // Demonstrating simple `add`
    System.out.println(simpleAdd.apply(4, 5));

    // Demonstrating curried `add`
    System.out.println(curriedAdd.apply(4).apply(5));

    // Curried version lets you perform partial application 
    // as demonstrated below.
    Function1<Integer, Integer> adder5 = curriedAdd.apply(5);
    System.out.println(adder5.apply(4));
    System.out.println(adder5.apply(6));
  }
}

上述Java代码的Haskell等价物:

simpleAdd :: (Int, Int) -> Int
simpleAdd (a, b) = a + b

curriedAdd :: Int -> Int -> Int
curriedAdd a b = a + b

main = do
  -- Demonstrating simpleAdd
  print $ simpleAdd (5, 4)

  -- Demonstrating curriedAdd
  print $ curriedAdd 5 4

  -- Demostrating partial application
  let adder5 = curriedAdd 5 in do
    print $ adder5 6
    print $ adder5 9
用户回答回答于

J示例Java代码 import static java.lang.System.out; // Tested with JDK 1.8.0-ea-b75 public class CurryingAndPartialFunctionApplication { public static void main(String[] args) { IntBinaryOperator simpleAdd = (a, b) -> a + b; IntFunction<IntUnaryOperator> curriedAdd = a -> b -> a + b; // Demonstrating simple add: out.println(simpleAdd.applyAsInt(4, 5)); // Demonstrating curried add: out.println(curriedAdd.apply(4).applyAsInt(5)); // Curried version lets you perform partial application: IntUnaryOperator adder5 = curriedAdd.apply(5); out.println(adder5.applyAsInt(4)); out.println(adder5.applyAsInt(6)); } }

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