Handy little Swift extensions for String and Int to simplify notation conversion

NotationHelper.swift

// A slick little number conversion extension
// Original source: http://stackoverflow.com/a/26811354/771460

extension String {
	var hexToInt       : Int    { return Int(strtoul(self, nil, 16))    }
	var hexToDouble    : Double { return Double(strtoul(self, nil, 16)) }
	var hexToBinary    : String { return String(hexToInt, radix: 2)    }
	var intToHex       : String { return String(toInt()!, radix: 16)    }
	var intToBinary    : String { return String(toInt()!, radix: 2)     }
	var binaryToInt    : Int    { return Int(strtoul(self, nil, 2))     }
	var binaryToDouble : Double { return Double(strtoul(self, nil, 2))  }
	var binaryToHex    : String { return String(binaryToInt, radix: 16) }
}

extension Int {
	var binaryString: String { return String(self, radix: 2)  }
	var hexString   : String { return String(self, radix: 16) }
	var doubleValue : Double { return Double(self) }
}

/* Examples ----
"ff".hexToInt               // "255"
"ff".hexToDouble            // "255.0"
"ff".hexToBinary            // "11111111"
"255".intToHex              // "ff"
"255".intToBinary           // "11111111"
"11111111".binaryToInt      // "255"
"11111111".binaryToDouble   // "255.0"
"11111111".binaryToHex      // "ff"
255.binaryString            // "11111111"
255.hexString               // "ff"
255.doubleValue             // 255.0
---- */