Reference method from different class as curried function

Question

There are two merge methods in RACSignal:

- (RACSignal *)merge:(RACSignal *)signal;
+ (RACSignal *)merge:(id<NSFastEnumeration>)signals;

When I write RACSignal.merge it references static method:

class func merge(signals: NSFastEnumeration!) -> RACSignal!

How to reference object method? I can't write self.merge, because it is in wrapper class and self is not RACSignal.

Answer 1

As methods in Swift are curried class functions, compiler has to decide which overload to choose.

To reference instance's merge method you need to specify it's exact type:

let instanceMerge: RACSignal -> RACSignal! -> RACSignal! = RACSignal.merge

Answer 2

The curried class function and the curried instance function have different signatures. Similarly as in

• Swift - get reference to a function with same name but different parameters

you can refer to each by specifying the signature explicitly.

I have no experience with RACSignal, so here is an artificial example that hopefully can be applied in your case:

class MyClass {
    class func foo(s : String) {
        println("class foo: \(s)")
    }
    func foo(s : String) {
        println("instance foo: \(s)")
    }
}

// Reference to the class method:
let f1 : String -> Void = MyClass.foo

// Call the class method:
f1("bar")
// Output: class foo: bar

// Reference to the instance method:
let f2 : MyClass -> String -> Void = MyClass.foo

// Call the instance method:
let obj = MyClass()
f2(obj)("bar")
// Output: instance foo: bar