How do you add default arguments when you don't control the source?

Using Swift
1

Sometimes, a closed source API will only be providing:

func f(a: Int, b: Int, c: Int) { }

when everybody wants:

func f(a: Int = 0, b: Int = 0, c: Int = 0) { }

Is macros the solution to generate this?

func f() { f(a: 0, b: 0, c: 0) }
func f(a: Int) { f(a: a, b: 0, c: 0) }
func f(b: Int) { f(a: 0, b: b, c: 0) }
func f(c: Int) { f(a: 0, b: 0, c: c) }
func f(a: Int, b: Int) { f(a: a, b: b, c: 0) }
func f(a: Int, c: Int) { f(a: a, b: 0, c: c) }
func f(b: Int, c: Int) { f(a: 0, b: b, c: c) }
2

Just create a custom function which has all the default parameters and calls the existing method.

3

No, that has a different signature. The different signature is not acceptable. The solution must add missing overloads.

4

Well, you should have specified that requirement in your first post.

Even if you do give it the same name in-source, those are still completely new functions whose names are mangled differently because of the differing argument count. The name will even be different merely because YourModule.f() is distinct from TheirModule.f().