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//===----------------------------------------------------------*- swift -*-===//
//
// This source file is part of the Swift Argument Parser open source project
//
// Copyright (c) 2021 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
//
//===----------------------------------------------------------------------===//
import ArgumentParser
import Foundation
extension Date: ExpressibleByArgument {
// parsed as `yyyy-mm-dd`
public init?(argument: String) {
// ensure the input argument is composed of exactly 3 components separated
// by dashes ('-')
let components = argument.split(separator: "-")
let empty = components.filter { $0.isEmpty }
guard components.count == 3, empty.count == 0 else { return nil }
// ensure the year component is exactly 4 characters
let _year = components[0]
guard _year.count == 4, let year = Int(_year) else { return nil }
// ensure the month component is exactly 2 characters
let _month = components[1]
guard _month.count == 2, let month = Int(_month) else { return nil }
// ensure the day component is exactly 2 characters
let _day = components[2]
guard _day.count == 2, let day = Int(_day) else { return nil }
// ensure the combination of year, month, day is valid
let dateComponents = DateComponents(
calendar: Calendar(identifier: .iso8601),
timeZone: TimeZone(identifier: "UTC"),
year: year,
month: month,
day: day)
guard dateComponents.isValidDate else { return nil }
guard let date = dateComponents.date else { return nil }
self = date
}
}
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