swift – 如何扩展float3或任何其他内置类型以符合Codable协议？

我尝试按照下面的建议编写一个基本扩展,如下所示,但是在初始化所有存储属性之前使用的错误’self’是为init中的每个赋值行呈现的.我假设这是因为编译器不确定Float.self是否在float3初始化之前定义,但我不知道如何解决这个问题.

此外,init的结尾表示从初始化器返回而没有初始化所有存储的属性,我假设除了x,y和z之外还有float3属性,但是我想知道是否有办法默认/忽略这些属性,和/或如何找到完整的属性列表,而不是挖掘simd中的所有float3扩展.

如果您对如何做到这一点有任何想法,那么分享它们将非常感激.谢谢！

import SceneKit

extension float3: Codable {
    public init(from decoder: Decoder) throws {
        let values = try decoder.container(keyedBy: CodingKeys.self)
        x = try values.decode(Float.self,forKey: .X)
        y = try values.decode(Float.self,forKey: .y)
        z = try values.decode(Float.self,forKey: .z)
    }

    public func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: CodingKeys.self)
        try container.encode(x,forKey: .X)
        try container.encode(y,forKey: .y)
        try container.encode(z,forKey: .z)
    }

    enum CodingKeys: String,CodingKey {
        case x
        case y
        case z
    }
}

这是simd文件中的(我认为完整的)float3定义：

/// A vector of three `Float`.  This corresponds to the C and
/// Obj-C type `vector_float3` and the C++ type `simd::float3`.
public struct float3 {

    public var x: Float

    public var y: Float

    public var z: Float

    /// Initialize to the zero vector.
    public init()

    /// Initialize a vector with the specified elements.
    public init(_ x: Float,_ y: Float,_ z: Float)

    /// Initialize a vector with the specified elements.
    public init(x: Float,y: Float,z: Float)

    /// Initialize to a vector with all elements equal to `scalar`.
    public init(_ scalar: Float)

    /// Initialize to a vector with elements taken from `array`.
    ///
    /// - Precondition: `array` must have exactly three elements.
    public init(_ array: [Float])

    /// Access individual elements of the vector via subscript.
    public subscript(index: int) -> Float
}

extension float3 : Equatable {

    /// True iff every element of lhs is equal to the corresponding element of
    /// rhs.
    public static func ==(lhs: float3,rhs: float3) -> Bool
}

extension float3 : CustomDebugStringConvertible {

    /// Debug String representation
    public var debugDescription: String { get }
}

extension float3 : ExpressibleByArrayLiteral {

    /// Initialize using `arrayLiteral`.
    ///
    /// - Precondition: the array literal must exactly three
    ///   elements.
    public init(arrayLiteral elements: Float...)
}

extension float3 : Collection {

    /// The position of the first element in a nonempty collection.
    ///
    /// If the collection is empty,`starTindex` is equal to `endIndex`.
    public var starTindex: Int { get }

    /// The collection's "past the end" position---that is,the position one
    /// greater than the last valid subscript argument.
    ///
    /// When you need a range that includes the last element of a collection,use
    /// the half-open range operator (`..<`) with `endIndex`. The `..<` operator
    /// creates a range that doesn't include the upper bound,so it's always
    /// safe to use with `endIndex`. For example:
    ///
    ///     let numbers = [10,20,30,40,50]
    ///     if let index = numbers.index(of: 30) {
    ///         print(numbers[index ..< numbers.endIndex])
    ///     }
    ///     // Prints "[30,50]"
    ///
    /// If the collection is empty,`endIndex` is equal to `starTindex`.
    public var endIndex: Int { get }

    /// Returns the position immediately after the given index.
    ///
    /// The successor of an index must be well defined. For an index `i` into a
    /// collection `c`,calling `c.index(after: i)` returns the same index every
    /// time.
    ///
    /// - Parameter i: A valid index of the collection. `i` must be less than
    ///   `endIndex`.
    /// - Returns: The index value immediately after `i`.
    public func index(after i: int) -> Int
}

extension float3 {

    /// Vector (elementwisE) sum of `lhs` and `rhs`.
    public static func +(lhs: float3,rhs: float3) -> float3

    /// Vector (elementwisE) difference of `lhs` and `rhs`.
    public static func -(lhs: float3,rhs: float3) -> float3

    /// Negation of `rhs`.
    prefix public static func -(rhs: float3) -> float3

    /// Elementwise product of `lhs` and `rhs` (A.k.a. the Hadamard or Schur
    /// vector product).
    public static func *(lhs: float3,rhs: float3) -> float3

    /// Scalar-Vector product.
    public static func *(lhs: Float,rhs: float3) -> float3

    /// Scalar-Vector product.
    public static func *(lhs: float3,rhs: Float) -> float3

    /// Elementwise quotient of `lhs` and `rhs`.
    public static func /(lhs: float3,rhs: float3) -> float3

    /// Divide vector by scalar.
    public static func /(lhs: float3,rhs: Float) -> float3

    /// Add `rhs` to `lhs`.
    public static func +=(lhs: inout float3,rhs: float3)

    /// Subtract `rhs` from `lhs`.
    public static func -=(lhs: inout float3,rhs: float3)

    /// Multiply `lhs` by `rhs` (elementwisE).
    public static func *=(lhs: inout float3,rhs: float3)

    /// Divide `lhs` by `rhs` (elementwisE).
    public static func /=(lhs: inout float3,rhs: float3)

    /// Scales `lhs` by `rhs`.
    public static func *=(lhs: inout float3,rhs: Float)

    /// Scales `lhs` by `1/rhs`.
    public static func /=(lhs: inout float3,rhs: Float)
}