Access to a global variable in Swift

Question

Given this example Swift code:

var a = 10; func foo() -> Int { var a = 20; return a; } 

How can the function foo access the global variable a with value 10 instead of the local a with value 20?

Note that both a and foo are not declared inside the class, but in the general module. I am looking for a way to tell Swift to access a globally defined var instead of a locally defined var.

Answer 1

I created a project in Xcode, a console application, the goal here is a module. Therefore, I called the project test , and the target has the same name, so in the project the module itself also has the name test . Any global definition will be an implicit call to test. . Just as global Swift functions are an implicit Swift. call Swift. e.g. Swift.print("...") .

 var a = 10; func foo() -> Int { let a = 20; Swift.print(test.a) // same as print(test.a) return a; } test.foo() // same as foo() 

Output:

ten

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So, you must add the module name in front of the variable in order to get global, not local, shading it.

Answer 2

Use the self keyword:

 func foo() -> Int { var a = 20; return self.a; } 

Answer 3

  func foo(bar:Any) -> Int { let a = 20 if bar is Bar { let c = bar as? Bar return c!.a } return a }