如何使用Typealias或Closure快速定义带有参数的常量？

Question

In Objective CI used to define constants using #defines as a way to quickly and explicitly define strings for localization and keep the code a little more clean.

For example:

#define DefineStringKey(x) static NSString *const x = @#x

This would let me define in constants that are named the same as the string so DefineStringKey(@"IntroTitle"); would create a constnat called IntroTitle with the value IntroTitle that I could refer to within my code (autocomplete and all).

I had an idea that I might be able to do the same in Swift but I can't seem to get the syntax correct using typealias or closures.

Type Alias

typealias DefineStringKey:(x:String) = let x:String = x 

Closure

let DefineStringKey:(String) = (String) -> () {
   (x:String) in
   let x:(String) = x
}

Clearly both examples I gave are incorrect. Is this something I can do in Swift via another method or is my syntax just off.

Edited to add a use case.

Answer 1

Unfortunately, Swift does not have macros, so you cannot define a constant (or variable) without writing out let myConstant = ... . What you can do is use a closure to define a constant that you can use within the closure's inner scope:

func defineStringKey(_ key: String, handler: (String) -> Void) {
    handler(key)
}

Put that anywhere in the global scope, and you can use it like this:

defineStringKey("IntroTitle") { IntroTitle in
    print(IntroTitle)
}

That prints out IntroTitle . This isn't very useful though, and I do not recommend using it. In swift, you have to explicitly type out your variable definitions.