CoreFoundation on Windows

adam-fowler · 2021-09-16T10:52:54.378Z

It appears CoreFoundation is not available on Swift for Windows.

I am doing the following to recognise if a NSNumber was initialized with a boolean and these functions are only available in CoreFoundation.

CFGetTypeID(number) == CFBooleanGetTypeID()

Is there either another method to identify an NSNumber initialized with a boolean, or will CoreFoundation be available for Windows soon?

tera · 2021-09-16T11:26:57.606Z

why do you need NSNumber instead of using swift native types if i may ask?

if you have it on windows you may try:
print(String(cString: number.objCType, encoding: .ascii)!)

but unfortunately this returns "c" for both Char and Boolean.

adam-fowler · 2021-09-16T11:29:43.303Z

I'm parsing dictionaries returned by JSONSerialization.jsonObject. I would much prefer not to have to deal with NSNumber at all but JSONSerialization code returns booleans as a NSNumber

tera · 2021-09-16T11:40:24.584Z

try this:

let dat = "{ \"some\" : true }".data(using: .utf8)!
let obj = try! JSONSerialization.jsonObject(with: dat, options: []) as! [String: Any]
let some = obj["some"]!
let someType = type(of: some)
let boolType = type(of: NSNumber(value: true))
let intType = type(of: NSNumber(value: 1))
print(someType)
assert(someType == boolType)
assert(someType != intType)

if some is NSNumber {
    print("is NSNumber")
} else {
    print("is not NSNumber")
}

xwu · 2021-09-16T12:33:30.575Z

See this post:

Swift 5.4 on Windows: error: missing required modules: 'CFXMLInterface', 'CoreFoundation'

CoreFoundation is not meant to be public, and the Windows port has generally been far more aggressive about preventing leakage of internal interfaces and encouraging cross-compilation.

adam-fowler · 2021-09-16T14:21:57.075Z

Thanks Mike,

That looks like it works

Jon_Shier · 2021-09-16T16:25:51.947Z

We use this in Alamofire, and it has been guarantee stable across platforms:

extension NSNumber {
    fileprivate var isBool: Bool {
        // Use Obj-C type encoding to check whether the underlying type is a `Bool`, as it's guaranteed as part of
        // swift-corelibs-foundation, per [this discussion on the Swift forums](https://forums.swift.org/t/alamofire-on-linux-possible-but-not-release-ready/34553/22).
        String(cString: objCType) == "c"
    }
}