Quick mistake. An undeclared String type is used
if we insert the line "case let dictionary as [String: AnyObject]:" inside the struct method everything works fine. But if used inside nested enums, we get the error "Used undefined type String"
public struct JSON {
public enum Type : Int {
case Number
case String
case Bool
case Array
case Dictionary
case Null
case Unknown
public static func evaluate(object: AnyObject) -> Type {
switch object {
case let dictionary as [String : AnyObject]: // this lines supply error. Use of undefined type String
return .Dictionary
default:
return .Unknown
}
}
} // enum Type
Can anyone explain why I am having an error with a string type?
It seems to enum Type
contain case String
and it hides String
what you want. I tried the code in Playground and after change there String
is no more error.
EDIT How about reading a SwiftyJSON project (only one file)
https://github.com/SwiftyJSON/SwiftyJSON/blob/master/Source/SwiftyJSON.swift
I am very similar to work (JSON Handling)
It also contains code that looks like this:
public enum Type :Int {
case Number
case String
case Bool
case Array
case Dictionary
case Null
case Unknown
}
I think this project will be very helpful for you. (and I think you can use this project)
As said in another answer, String
internally enum Type
refers to the enum value. The same problem would arise when using
let a : Array<Int> = []
let b : Bool = false
inside methods enum Type
. Renaming the enum values is probably the best solution.
But for the sake of completeness: you can fix the problem by adding the module name "Swift" explicitly to reference the
String
type:
case let dictionary as [Swift.String : AnyObject]:
If you want to fix this without renaming the enum case, you can change the type of the argument to Swift.String
, i.e .:
case let dictionary as [Swift.String : AnyObject]:
This should work (I had a similar problem and this solved it).