如何在 Swift 中进行通用扩展？

Question

I want make a generic extension for avoiding me to repeating my code for deferent types. here is my code need to get fixed!

    extension Bool {
    
    func print() { Swift.print(self.description) }
    
}

extension Int {
    
    func print() { Swift.print(self.description) }
    
}

extension String {
    
    func print() { Swift.print(self.description) }
    
}

---

 extension <T> {
    
    func print() { Swift.print(self.description) }
    
}



 

Answer 1

Your extension is not "generic" in the sense that it can apply to any type. It can only apply to types that have a description property. Well, which types have a description property? Every type that conforms to CustomStringConvertible does!

So you should create an extension of CustomStringConvertible :

extension CustomStringConvertible {
    
    func print() { Swift.print(self.description) }
    
}

_{(Note that there could be a type that have a description property, but does not conform to CustomStringConvertible , but most types in the standard libraries aren't like this)}

Truly generic extensions are something else , and is currently being proposed, ie not part of Swift yet.