We were told that Bool can't downcast to AnyObject in Swift. However, with
Foundation framework, we can.
do {
let a:Bool = true
let object:AnyObject = a as AnyObject
object.dynamicType
// __NSCFBoolean.Type
let b:Bool = object as! Bool
b // true
}
This feature works in some code automatically (like in a Dictionary), but
in some other codes(like in a function), you have to downcast it yourself.
do {
var dictionary = Dictionary<String, AnyObject>()
func update<T:AnyObject>(value:T, key:String) {
dictionary.updateValue(value, forKey: key)
}
let aBool = true
let key = "testBool"
dictionary.updateValue(aBool, forKey: key)
// works
update(aBool, key: key)
// doesn't work. cannot invoke 'update' with an argument list of type
'(Bool, key: String)'
update(aBool as AnyObject, key:key)
// works
}
My question: Is this normal? Should it all be automatic or not?
Zhaoxin
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