Depend only on Foundation Essentials

Package.swift

@@ -3,6 +3,7 @@ import PackageDescription
 
 let package = Package(
     name: "Yams",
+    platforms: [.iOS(.v13), .macOS(.v13), .tvOS(.v13), .watchOS(.v6)],
     products: [
         .library(name: "Yams", targets: ["Yams"])
     ],

Package@swift-6.swift

@@ -3,6 +3,7 @@ import PackageDescription
 
 let package = Package(
     name: "Yams",
+    platforms: [.iOS(.v13), .macOS(.v13), .tvOS(.v13), .watchOS(.v6)],
     products: [
         .library(name: "Yams", targets: ["Yams"])
     ],

README.md

@@ -84,7 +84,11 @@ and a third one for a [Yams-native](#yamsnode) representation.
   `Data`.
 
 ```swift
+#if canImport(FoundationEssentials)
+import FoundationEssentials
+#else
 import Foundation
+#endif
 import Yams
 
 struct S: Codable {
@@ -184,7 +188,11 @@ When Apple's Combine framework is available, `YAMLDecoder` conforms to the
 
 ```swift
 import Combine
+#if canImport(FoundationEssentials)
+import FoundationEssentials
+#else
 import Foundation
+#endif
 import Yams
 
 func fetchBook(from url: URL) -> AnyPublisher<Book, Error> {

Sources/Yams/Anchor.swift

@@ -5,13 +5,18 @@
 //  Created by Adora Lynch on 8/9/24.
 //  Copyright (c) 2024 Yams. All rights reserved.
 
+#if canImport(FoundationEssentials)
+import FoundationEssentials
+#else
 import Foundation
+#endif
 
 /// A representation of a YAML tag see: https://yaml.org/spec/1.2.2/
 /// Types interested in Encoding and Decoding Anchors should
 /// conform to YamlAnchorProviding and YamlAnchorCoding respectively.
 public final class Anchor: RawRepresentable, ExpressibleByStringLiteral, Codable, Hashable {
 
+#if !canImport(FoundationEssentials)
     /// A CharacterSet containing only characters which are permitted by the underlying cyaml implementation
     public static let permittedCharacters = CharacterSet.lowercaseLetters
                                                 .union(.uppercaseLetters)
@@ -22,6 +27,15 @@ public final class Anchor: RawRepresentable, ExpressibleByStringLiteral, Codable
     public static func is_cyamlAlpha(_ string: String) -> Bool {
         Anchor.permittedCharacters.isSuperset(of: .init(charactersIn: string))
     }
+#else
+    /// An Set containing only characters which are permitted by the underlying cyaml implementation
+    public static let permittedCharacters = Set( "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_")
+
+    /// Returns true if and only if `string` contains only characters which are also in `permittedCharacters`
+    public static func is_cyamlAlpha(_ string: String) -> Bool {
+        Anchor.permittedCharacters.isSuperset(of: .init(string))
+    }
+#endif
 
     public let rawValue: String
 

Sources/Yams/Constructor.swift

@@ -6,7 +6,11 @@
 //  Copyright (c) 2016 Yams. All rights reserved.
 //
 
+#if canImport(FoundationEssentials)
+import FoundationEssentials
+#else
 import Foundation
+#endif
 
 /// Constructors are used to translate `Node`s to Swift values.
 public final class Constructor {
@@ -175,24 +179,19 @@
     ///
     /// - returns: An instance of `Date`, if one was successfully extracted from the scalar.
     public static func construct(from scalar: Node.Scalar) -> Date? {
-        let range = NSRange(location: 0, length: scalar.string.utf16.count)
-        guard let result = timestampPattern.firstMatch(in: scalar.string, options: [], range: range),
-            result.range.location != NSNotFound else {
+        guard let result = try! timestampPattern.firstMatch(in: scalar.string) else {
                 return nil
         }
-        let components = (1..<result.numberOfRanges).map {
-            scalar.string.substring(with: result.range(at: $0))
-        }
 
         var datecomponents = DateComponents()
         datecomponents.calendar = gregorianCalendar
-        datecomponents.year = components[0].flatMap { Int($0) }
-        datecomponents.month = components[1].flatMap { Int($0) }
-        datecomponents.day = components[2].flatMap { Int($0) }
-        datecomponents.hour = components[3].flatMap { Int($0) }
-        datecomponents.minute = components[4].flatMap { Int($0) }
-        datecomponents.second = components[5].flatMap { Int($0) }
-        let nanoseconds: TimeInterval? = components[6].flatMap { fraction in
+        datecomponents.year = result["year"]?.substring.flatMap { Int($0) }
+        datecomponents.month = result["month"]?.substring.flatMap { Int($0) }
+        datecomponents.day = result["day"]?.substring.flatMap { Int($0) }
+        datecomponents.hour = result["hour"]?.substring.flatMap { Int($0) }
+        datecomponents.minute = result["minute"]?.substring.flatMap { Int($0) }
+        datecomponents.second = result["second"]?.substring.flatMap { Int($0) }
+        let nanoseconds: TimeInterval? = result["fraction"]?.substring.flatMap { fraction in
             let length = fraction.count
             let nanoseconds: Int?
             if length < 9 {
@@ -206,13 +205,13 @@
         }
         datecomponents.timeZone = {
             var seconds = 0
-            if let hourInSecond = components[9].flatMap({ Int($0) }).map({ $0 * 60 * 60 }) {
+            if let hourInSecond = result["tz_hour"]?.substring.flatMap({ Int($0) }).map({ $0 * 60 * 60 }) {
                 seconds += hourInSecond
             }
-            if let minuteInSecond = components[10].flatMap({ Int($0) }).map({ $0 * 60 }) {
+            if let minuteInSecond = result["tz_minute"]?.substring.flatMap({ Int($0) }).map({ $0 * 60 }) {
                 seconds += minuteInSecond
             }
-            if components[8] == "-" { // sign
+            if result["tz_sign"]?.substring == "-" { // sign
                 seconds *= -1
             }
             return TimeZone(secondsFromGMT: seconds)
@@ -222,17 +221,17 @@
 
     private static let gregorianCalendar = Calendar(identifier: .gregorian)
 
-    private static let timestampPattern: NSRegularExpression = pattern([
-        "^([0-9][0-9][0-9][0-9])",          // year
-        "-([0-9][0-9]?)",                   // month
-        "-([0-9][0-9]?)",                   // day
+    private static let timestampPattern: Regex<AnyRegexOutput> = pattern([
+        "^(?<year>[0-9][0-9][0-9][0-9])",                       // year
+        "-(?<month>[0-9][0-9]?)",                               // month
+        "-(?<day>[0-9][0-9]?)",                                 // day
         "(?:(?:[Tt]|[ \\t]+)",
-        "([0-9][0-9]?)",                    // hour
-        ":([0-9][0-9])",                    // minute
-        ":([0-9][0-9])",                    // second
-        "(?:\\.([0-9]*))?",                 // fraction
-        "(?:[ \\t]*(Z|([-+])([0-9][0-9]?)", // tz_sign, tz_hour
-        "(?::([0-9][0-9]))?))?)?$"          // tz_minute
+        "(?<hour>[0-9][0-9]?)",                                 // hour
+        ":(?<minute>[0-9][0-9])",                               // minute
+        ":(?<second>[0-9][0-9])",                               // second
+        "(?:\\.(?<fraction>[0-9]*))?",                          // fraction
+        "(?:[ \\t]*(Z|(?<tz_sign>[-+])(?<tz_hour>[0-9][0-9]?)", // tz_sign, tz_hour
+        "(?::(?<tz_minute>[0-9][0-9]))?))?)?$"                  // tz_minute
         ].joined()
     )
 }
@@ -394,6 +393,12 @@
 
 // MARK: - Types that can't conform to ScalarConstructible
 
+#if !canImport(ObjectiveC) && canImport(FoundationEssentials)
+public struct NSNull: Hashable {
+    public init() {}
+}
+#endif
+
 extension NSNull/*: ScalarConstructible*/ {
     /// Construct an instance of `NSNull`, if possible, from the specified scalar.
     ///

Sources/Yams/Decoder.swift

@@ -6,7 +6,11 @@
 //  Copyright (c) 2017 Yams. All rights reserved.
 //
 
+#if canImport(FoundationEssentials)
+import FoundationEssentials
+#else
 import Foundation
+#endif
 
 /// `Codable`-style `Decoder` that can be used to decode a `Decodable` type from a given `String` and optional
 /// user info mapping. Similar to `Foundation.JSONDecoder`.

Sources/Yams/Emitter.swift

@@ -15,7 +15,11 @@ internal import CYaml
 @_implementationOnly import CYaml
 #endif
 #endif
+#if canImport(FoundationEssentials)
+import FoundationEssentials
+#else
 import Foundation
+#endif
 
 /// Produce a YAML string from objects.
 ///

Sources/Yams/Node.swift

@@ -6,7 +6,11 @@
 //  Copyright (c) 2016 Yams. All rights reserved.
 //
 
+#if canImport(FoundationEssentials)
+import FoundationEssentials
+#else
 import Foundation
+#endif
 
 /// YAML Node.
 public enum Node: Hashable {

Sources/Yams/Parser.swift

@@ -16,7 +16,11 @@ internal import CYaml
 @_implementationOnly import CYaml
 #endif
 #endif
+#if canImport(FoundationEssentials)
+import FoundationEssentials
+#else
 import Foundation
+#endif
 
 /// Parse all YAML documents in a String
 /// and produce corresponding Swift objects.

Sources/Yams/Representer.swift

@@ -6,7 +6,11 @@
 //  Copyright (c) 2017 Yams. All rights reserved.
 //
 
+#if canImport(FoundationEssentials)
+import FoundationEssentials
+#else
 import Foundation
+#endif
 
 public extension Node {
     /// Initialize a `Node` with a value of `NodeRepresentable`.

Sources/Yams/Resolver.swift

@@ -6,17 +6,21 @@
 //  Copyright (c) 2016 Yams. All rights reserved.
 //
 
+#if canImport(FoundationEssentials)
+import FoundationEssentials
+#else
 import Foundation
+#endif
 
 /// Class used to resolve nodes to tags based on customizable rules.
 public final class Resolver: Sendable {
     /// Rule describing how to resolve tags from regex patterns.
     public struct Rule: Sendable {
         /// The tag name this rule applies to.
         public let tag: Tag.Name
-        fileprivate let regexp: NSRegularExpression
+        fileprivate let regexp: Regex<AnyRegexOutput>
         /// The regex pattern used to resolve this rule.
-        public var pattern: String { return regexp.pattern }
+        public let pattern: String
 
         /// Create a rule with the specified tag name and regex pattern.
         ///
@@ -26,7 +30,8 @@
         /// - throws: Throws an error if the regular expression pattern is invalid.
         public init(_ tag: Tag.Name, _ pattern: String) throws {
             self.tag = tag
-            self.regexp = try .init(pattern: pattern, options: [])
+            self.regexp = try .init(pattern)
+            self.pattern = pattern
         }
     }
 
@@ -85,7 +90,10 @@
     }
 
     func resolveTag(from string: String) -> Tag.Name {
-        for rule in rules where rule.regexp.matches(in: string) {
+        let rule = rules.first { rule in
+            try! rule.regexp.firstMatch(in: string) != nil
+        }
+        if let rule {
             return rule.tag
         }
         return .str
@@ -156,20 +164,16 @@
     // swiftlint:enable force_try
 }
 
-func pattern(_ string: String) -> NSRegularExpression {
+func pattern(_ string: String) -> Regex<AnyRegexOutput> {
     do {
-        return try .init(pattern: string, options: [])
+        return try .init(string)
     } catch {
         fatalError("unreachable")
     }
 }
 
-private extension NSRegularExpression {
-    func matches(in string: String) -> Bool {
-        let range = NSRange(location: 0, length: string.utf16.count)
-        if let match = firstMatch(in: string, options: [], range: range) {
-            return match.range.location != NSNotFound
-        }
-        return false
-    }
-}
+#if swift(>=6.0)
+extension Regex: @retroactive @unchecked Sendable {}
+#else
+extension Regex: @unchecked Sendable {}
+#endif

Sources/Yams/String+Yams.swift

@@ -6,7 +6,11 @@
 //  Copyright (c) 2016 Yams. All rights reserved.
 //
 
+#if canImport(FoundationEssentials)
+import FoundationEssentials
+#else
 import Foundation
+#endif
 
 extension String {
     typealias LineNumberColumnAndContents = (lineNumber: Int, column: Int, contents: String)

Sources/Yams/YamlError.swift

@@ -15,7 +15,11 @@ internal import CYaml
 @_implementationOnly import CYaml
 #endif
 #endif
+#if canImport(FoundationEssentials)
+import FoundationEssentials
+#else
 import Foundation
+#endif
 
 /// Errors thrown by Yams APIs.
 public enum YamlError: Error {

Tests/YamsTests/ConstructorTests.swift

@@ -6,7 +6,11 @@
 //  Copyright (c) 2016 Yams. All rights reserved.
 //
 
+#if canImport(FoundationEssentials)
+import FoundationEssentials
+#else
 import Foundation
+#endif
 import XCTest
 import Yams
 

Tests/YamsTests/EncoderTests.swift

@@ -6,7 +6,11 @@
 //  Copyright (c) 2017 Yams. All rights reserved.
 //
 
+#if canImport(FoundationEssentials)
+import FoundationEssentials
+#else
 import Foundation
+#endif
 import XCTest
 import Yams
 

Tests/YamsTests/NodeTests.swift

@@ -6,7 +6,11 @@
 //  Copyright (c) 2016 Yams. All rights reserved.
 //
 
+#if canImport(FoundationEssentials)
+import FoundationEssentials
+#else
 import Foundation
+#endif
 import XCTest
 import Yams
 

Tests/YamsTests/PerformanceTests.swift

@@ -6,7 +6,11 @@
 //  Copyright (c) 2016 Yams. All rights reserved.
 //
 
+#if canImport(FoundationEssentials)
+import FoundationEssentials
+#else
 import Foundation
+#endif
 import XCTest
 import Yams
 

Tests/YamsTests/RepresenterTests.swift

@@ -6,7 +6,11 @@
 //  Copyright (c) 2017 Yams. All rights reserved.
 //
 
+#if canImport(FoundationEssentials)
+import FoundationEssentials
+#else
 import Foundation
+#endif
 import XCTest
 import Yams