feat: Add Value Enum.

Sources/FoundationX/Value.swift

@@ -0,0 +1,59 @@
+//
+//  Value.swift
+//  FoundationX
+// 
+//  Created by Guanghui Liang on 2024/1/21.
+//  Copyright © 2024 Guanghui Liang. All rights reserved.
+//
+
+import Foundation
+
+public protocol DefaultValue {
+    associatedtype ValueType: Equatable
+    static var defaultValue: ValueType { get }
+}
+
+public enum Value<T>: Equatable where T: Equatable {
+    case none
+    case some(value: T)
+}
+
+extension Value where T: DefaultValue, T.ValueType == T {
+    public var realValue: T {
+        if case let Self.some(value) = self {
+            return value
+        } else {
+            return T.defaultValue
+        }
+    }
+}
+
+extension Bool: DefaultValue {
+    public static var defaultValue: Bool {
+        return false
+    }
+}
+
+extension Int: DefaultValue {
+    public static var defaultValue: Int {
+        return 0
+    }
+}
+
+extension Float: DefaultValue {
+    public static var defaultValue: Self {
+        return 0.0
+    }
+}
+
+extension Double: DefaultValue {
+    public static var defaultValue: Self {
+        return 0.0
+    }
+}
+
+extension String: DefaultValue {
+    public static var defaultValue: Self {
+        return ""
+    }
+}

Sources/FoundationX/XLogger.swift

@@ -2,7 +2,7 @@
 //  Logger.swift
 //  FoundationX 
 // 
-//  Created by 梁光辉 on 2023/3/8.
+//  Created by Guanghui Liang on 2023/3/8.
 //  Copyright © 2023 Guanghui Liang. All rights reserved.
 //