precedencegroup PowerPrecedence {
higherThan: MultiplicationPrecedence
associativity: right
}
infix operator **: PowerPrecedence
func **(base: Double, power: Double) -> Double {
return pow(base, power)
}
higherThan: MultiplicationPrecedence
associativity: right
}
infix operator **: PowerPrecedence
func **(base: Double, power: Double) -> Double {
return pow(base, power)
}
2017-08-18
Swift3 自定義雙目運算符指定結合規則和優先級的方式改了,都封裝在 precedencegroup 里,視頻中的例子變成這樣了:
infix operator **: MultiplicationPrecedence
func **(base: Double, power: Double) -> Double {
return pow(base, power)
}
其中 MultiplicationPrecedence 表示按乘除法的結合規則和優先級,對應加減法是:AdditionPrecedence
infix operator **: MultiplicationPrecedence
func **(base: Double, power: Double) -> Double {
return pow(base, power)
}
其中 MultiplicationPrecedence 表示按乘除法的結合規則和優先級,對應加減法是:AdditionPrecedence
2017-08-18