Passing non-escaping closure to function expecting an @escaping closure

Question

How can I solve the issue of passing non-escaping closure to function expecting an @escaping closure, with this limitation that I cannot make the function non-escaping.

Here is my codes and the issue:

func function1(string: @escaping (() -> String) -> Void) {

    string({ "Hello, world!" })

}

func function2(value: @escaping () -> String) {  // I cannot remove @escaping here, because the function needs it to work!

    print(value())

    // some more codes ...

}

func function3() {

    function1(string: { stringValue in

        function2(value: stringValue)         // issue is here!

    })
}

Answer 1

Add @escaping to the inner function:

func function1(string: @escaping (@escaping () -> String) -> Void) {
    string({ "Hello, world!" })
}
func function2(value: @escaping () -> String) { 
    print(value())
}
func function3() {
    function1(string: { stringValue in
        function2(value: stringValue)
    })
}

(Part of the problem here is that you have given your parameters really bad names, so that you confuse yourself about what's what.)