prefix operator prefix -- { associativity precedence } Declarations prefix func --(inout: Double) Declaration prefix func --(inout rhs: Double) -> Double prefix func --(inout: Float) Declaration prefix func --(inout rhs: Float) -> Float prefix func --(inout: Float80) Declaration prefix func --(inout rhs: Float80) -> Float80 prefix func --(inout: Int) Declaration prefix func --(inout x: Int) -> Int prefix func --(inout: Int8) Declaration prefix func --(inout x: Int8) -> Int8 prefix func --(inout: Int16) Declaration prefix func --(inout x: Int16) -> Int16 prefix func --(inout: Int32) Declaration prefix func --(inout x: Int32) -> Int32 prefix func --(inout: Int64) Declaration prefix func --(inout x: Int64) -> Int64 prefix func --(inout: UInt) Declaration prefix func --(inout x: UInt) -> UInt prefix func --(inout: UInt8) Declaration prefix func --(inout x: UInt8) -> UInt8 prefix func --(inout: UInt16) Declaration prefix func --(inout x: UInt16) -> UInt16 prefix func --(inout: UInt32) Declaration prefix func --(inout x: UInt32) -> UInt32 prefix func --(inout: UInt64) Declaration prefix func --(inout x: UInt64) -> UInt64 prefix func -- <T : _BidirectionalIndexType>(inout: T) Declaration prefix func --<T : _BidirectionalIndexType>(inout x: T) -> T