protocol BooleanType A type that represents a Boolean value. Types that conform to the BooleanType protocol can be used as the condition in control statements (if, while, C-style for) and other logical value contexts (e.g., case statement guards). Only three types provided by Swift, Bool, DarwinBoolean, and ObjCBool, conform to BooleanType. Expanding this set to include types that represent more than simple boolean values is discouraged. Inheritance View Protocol Hierarchy → Import import Swift Instance Variables var boolValue: Bool Required The value of self, expressed as a Bool. Declaration var boolValue: Bool { get }