Will Hawkins
56 lines
1.4 KiB
Swift
56 lines
1.4 KiB
Swift
public struct Error: Equatable {
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public private(set) var msg: String
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public init(withMessage msg: String) {
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self.msg = msg
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}
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}
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public struct Nothing: CustomStringConvertible {
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public var description: String {
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return "Nothing"
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}
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public init() {}
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}
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public enum Result<T>: Equatable, CustomStringConvertible {
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case Ok(T)
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case Error(Error)
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public static func == (lhs: Result, rhs: Result) -> Bool {
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switch (lhs, rhs) {
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case (Ok, Ok):
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return true
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case (Error(let le), Error(let re)):
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return le.msg == re.msg
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default:
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return false
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}
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}
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public func error() -> Error? {
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if case Result.Error(let e) = self {
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return e
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}
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return nil
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}
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public var description: String {
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switch self {
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case Result.Error(let e):
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return e.msg
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case Result.Ok(let o):
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return "\(o)"
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}
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}
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}
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@freestanding(expression) public macro RequireOkResult<T>(_: Result<T>) -> Bool =
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#externalMacro(module: "P4Macros", type: "RequireResult")
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@freestanding(expression) public macro RequireErrorResult<T>(_: Error, _: Result<T>) -> Bool =
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#externalMacro(module: "P4Macros", type: "RequireErrorResult")
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@freestanding(expression) public macro UseOkResult<T>(_: Result<T>) -> T =
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#externalMacro(module: "P4Macros", type: "UseOkResult")
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