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objective-cxcodeswiftosx-yosemite

Type 'Boolean' does not conform to protocol 'BooleanType'


In attempting to create a Launch Helper as per the Apple docs (and tutorial-ized), I seem to be hitting a hiccup caused by porting the Objective-C code into Swift... who's compiler couldn't be any more redundant in this case.

import ServiceManagement

let launchDaemon: CFStringRef = "com.example.ApplicationLauncher"

if SMLoginItemSetEnabled(launchDaemon, true) // Error appears here
{
    // ...
}

The error seems to consistently be:

Type 'Boolean' does not conform to protocol 'BooleanType'

I have tried casting to Bool in a number of locations, in case I'm simply dealing with a redundant, archaic primitive (either brought in by Obj-C or Core Foundation), to no avail.

Just in case, I have tried casting the response:

SMLoginItemSetEnabled(launchDaemon, true) as Bool

which yields the error:

'Boolean' is not convertible to 'Bool'

...seriously?


Solution

  • Boolean is a "historic Mac type" and declared as

    typealias Boolean = UInt8
    

    so this compiles:

    if SMLoginItemSetEnabled(launchDaemon, Boolean(1)) != 0 { ... }
    

    With the following extension methods for the Boolean type (and I am not sure if this has been posted before, I cannot find it right now):

    extension Boolean : BooleanLiteralConvertible {
        public init(booleanLiteral value: Bool) {
            self = value ? 1 : 0
        }
    }
    extension Boolean : BooleanType {
        public var boolValue : Bool {
            return self != 0
        }
    }
    

    you can just write

    if SMLoginItemSetEnabled(launchDaemon, true) { ... }
    
    • The BooleanLiteralConvertible extension allows the automatic conversion of the second argument true to Boolean.
    • The BooleanType extension allows the automatic conversion of the Boolean return value of the function to Bool for the if-statement.

    Update: As of Swift 2 / Xcode 7 beta 5, the "historic Mac type" Boolean is mapped to Swift as Bool, which makes the above extension methods obsolete.