Cleanly converting an Objective-C Boolean to a Swift Bool?

Question

Is there an easy way to do this that I'm missing? Right now I'm doing this like so:

let doesConformNumber: NSNumber = NSNumber(unsignedChar: UTTypeConformsTo(utiCF, typeCF))
if doesConformNumber.boolValue {
    return true
}

If I try to do a simple cast like so:

let testBool: Bool = UTTypeConformsTo(utiCF, typeCF)

I get the error 'Boolean' is not convertible to 'Bool'

Anyone have a cleaner way of doing this conversion?

Note that `UTTypeConformsTo` returns a CoreFoundation boolean, `Boolean`; an Objective-C boolean is a `BOOL`. The question is a good one, the summary is just a bit misleading. But probably in a good way for searches. :) — Steven Fisher, Mar 30 '15 at 20:07
Please note that at some point in the years since this question was asked, Apple changed the way Swift exposes `UTTypeConformsTo` so that it returns a native Swift `Bool`. No conversion is necessary in modern Swift. — rob mayoff, Nov 30 '18 at 21:28

score 6 · Accepted Answer · answered Aug 29 '14 at 05:45

6

UTTypeConformsTo() returns a Boolean, which is a type alias for Int8 and not directly convertible to Bool. The simplest way would be

let testBool : Bool = UTTypeConformsTo(utiCF, typeCF) != 0

where the type annotation is actually not necessary:

let testBool = UTTypeConformsTo(utiCF, typeCF) != 0

answered Aug 29 '14 at 05:45

Martin R

1

what's the difference between Bool and Boolean? – Apr 24 '15 at 08:51
1

@jawanam: `Boolean` is a "historic Mac type" and defined as `Int8`. `Bool` is the Swift boolean type. Compare http://stackoverflow.com/questions/27304158/type-boolean-does-not-conform-to-protocol-booleantype. – Martin R Apr 24 '15 at 08:56
So it should use Bool over Boolean whenever it's possible? – Apr 25 '15 at 03:39

1 Answers1