swift - Swift 运算符的优先级是多少？

Question

我想查找某些运算符的优先级。某处有它们的列表吗？我还没找到。

Answer 1

Updated for Swift 3.0

swift 3.0

现在有一个 page在 Swift 文档中。

下面列出了所有优先组(也可以通过单击 import Swift 的命令看到):

precedencegroup BitwiseShiftPrecedence {
    higherThan: MultiplicationPrecedence
}

precedencegroup FunctionArrowPrecedence {
    associativity: right
}

precedencegroup AssignmentPrecedence {
    associativity: right
    assignment: true
    higherThan: FunctionArrowPrecedence
}

precedencegroup RangeFormationPrecedence {
    higherThan: CastingPrecedence
}

precedencegroup CastingPrecedence {
    higherThan: NilCoalescingPrecedence
}

precedencegroup AdditionPrecedence {
    associativity: left
    higherThan: RangeFormationPrecedence
}

precedencegroup NilCoalescingPrecedence {
    associativity: right
    higherThan: ComparisonPrecedence
}

precedencegroup ComparisonPrecedence {
    higherThan: LogicalConjunctionPrecedence
}

precedencegroup LogicalConjunctionPrecedence {
    associativity: left
    higherThan: LogicalDisjunctionPrecedence
}

precedencegroup LogicalDisjunctionPrecedence {
    associativity: left
    higherThan: TernaryPrecedence
}

precedencegroup DefaultPrecedence {
    higherThan: TernaryPrecedence
}

precedencegroup TernaryPrecedence {
    associativity: right
    higherThan: AssignmentPrecedence
}

precedencegroup MultiplicationPrecedence {
    associativity: left
    higherThan: AdditionPrecedence
}

swift 2.1

在 Swift header 中:

infix operator %= {
    associativity right
    precedence 90
    assignment
}

infix operator >= {
    associativity none
    precedence 130
}

infix operator != {
    associativity none
    precedence 130
}

infix operator <<= {
    associativity right
    precedence 90
    assignment
}

infix operator || {
    associativity left
    precedence 110
}

infix operator += {
    associativity right
    precedence 90
    assignment
}

infix operator / {
    associativity left
    precedence 150
}

infix operator - {
    associativity left
    precedence 140
}

infix operator << {
    associativity none
    precedence 160
}

infix operator |= {
    associativity right
    precedence 90
    assignment
}

infix operator >>= {
    associativity right
    precedence 90
    assignment
}

infix operator <= {
    associativity none
    precedence 130
}

infix operator -= {
    associativity right
    precedence 90
    assignment
}

infix operator ?? {
    associativity right
    precedence 131
}

infix operator > {
    associativity none
    precedence 130
}

infix operator ~= {
    associativity none
    precedence 130
}

infix operator + {
    associativity left
    precedence 140
}

infix operator ^ {
    associativity left
    precedence 140
}

infix operator ... {
    associativity none
    precedence 135
}

infix operator /= {
    associativity right
    precedence 90
    assignment
}

infix operator * {
    associativity left
    precedence 150
}

infix operator *= {
    associativity right
    precedence 90
    assignment
}

infix operator & {
    associativity left
    precedence 150
}

infix operator !== {
    associativity none
    precedence 130
}

infix operator % {
    associativity left
    precedence 150
}

infix operator && {
    associativity left
    precedence 120
}

infix operator &* {
    associativity left
    precedence 150
}

infix operator &+ {
    associativity left
    precedence 140
}

infix operator &= {
    associativity right
    precedence 90
    assignment
}

infix operator >> {
    associativity none
    precedence 160
}

infix operator &- {
    associativity left
    precedence 140
}

infix operator === {
    associativity none
    precedence 130
}

infix operator ~> {
    associativity left
    precedence 255
}

infix operator ..< {
    associativity none
    precedence 135
}

infix operator < {
    associativity none
    precedence 130
}

infix operator == {
    associativity none
    precedence 130
}

infix operator ^= {
    associativity right
    precedence 90
    assignment
}

infix operator | {
    associativity left
    precedence 140
}