[Enhancement] Lossy codable list property wrapper (#19)

This PR contains the work done to implement the `LossyCodableList` struct and property wrapper, which is used in lossy decoding/encoding processes.

Co-authored-by: Javier Cicchelli <javier@rock-n-code.com>
Reviewed-on: #19

Sources/Core/Property Wrappers/LossyCodableList.swift

@@ -0,0 +1,89 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the SwiftLibs open source project
+//
+// Copyright (c) 2023 Röck+Cöde VoF. and the SwiftLibs project authors
+// Licensed under the EUPL 1.2 or later.
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of SwiftLibs project authors
+//
+//===----------------------------------------------------------------------===//
+
+@propertyWrapper
+/// This property wrapper provides a generic type that acts as a thin wrapper around an array of `Elements` instances to allow a lossy decoding and or encoding process.
+public struct LossyCodableList<Element> {
+    
+    // MARK: Properties
+    
+    private var elements: [Element]
+    
+    /// Provides read/write access to the array of `Element` instances.
+    public var wrappedValue: [Element] {
+        get { elements }
+        set { elements = newValue }
+    }
+    
+    // MARK: Initialisers
+    
+    /// Initialises this property wrapper.
+    public init() {
+        self.elements = []
+    }
+
+}
+
+// MARK: - Decodable
+
+extension LossyCodableList: Decodable where Element: Decodable {
+    
+    // MARK: Initialisers
+    
+    /// Initialises the struct with a lossy decoder.
+    /// - Parameter decoder: The decoder to use for the lossy decoder process.
+    public init(from decoder: Decoder) throws {
+        let container = try decoder.singleValueContainer()
+        let wrappers = try container.decode([ElementWrapper].self)
+        
+        self.elements = wrappers.compactMap(\.element)
+    }
+
+}
+
+// MARK: - Encodable
+
+extension LossyCodableList: Encodable where Element: Encodable {
+    
+    // MARK: Functions
+    
+    /// Encodes an array of `Element` instances loosely.
+    /// - Parameter encoder: The encoder to use for the lossy encoding process.
+    public func encode(to encoder: Encoder) throws {
+        var container = encoder.unkeyedContainer()
+        
+        elements.forEach { element in
+            try? container.encode(element)
+        }
+    }
+
+}
+
+// MARK: - Structs
+
+private extension LossyCodableList where Element: Decodable {
+    struct ElementWrapper: Decodable {
+        
+        // MARK: Properties
+        
+        var element: Element?
+        
+        // MARK: Initialisers
+        
+        init(from decoder: Decoder) throws {
+            let container = try decoder.singleValueContainer()
+            
+            self.element = try? container.decode(Element.self)
+        }
+
+    }
+}