XMLTree.swift: Converts tree structure into XML data.

Sources/Tree/Node.swift

@@ -20,7 +20,7 @@ public final class Node<Element: Identifiable>: Identifiable {
 ///
 /// This value can be any type that conforms to `Identifiable`.
 ///
-	public let element: Element
+	public var element: Element
 
 /// The parent node for this node.
 ///

Sources/Tree/XMLTree.swift

@@ -0,0 +1,73 @@
+//
+//  XMLTree.swift
+//  Tree
+//
+//  Created by joshydotpoo on 3/8/2024.
+//
+
+import Foundation
+
+public struct XMLTree<Element:Identifiable> {
+
+    private(set) var data:Data?
+
+    let property:KeyPath<Element, String>
+    let attributes:[String: KeyPath<Element, String?>]
+
+    /// XMLTree converts the tree into an XML file.
+    /// - Parameters:
+    ///   - root: root node of the tree
+    ///   - property: string property of generic Element used as the tag name
+    ///   - attributes: dictionary of string property pairs, where the string is the attribute name and the property is used for attribute value.
+    public init(root:Node<Element>,
+         using property:KeyPath<Element, String>,
+         assigning attributes:[String: KeyPath<Element, String?>] = [:])
+    {
+        self.property = property
+        self.attributes = attributes
+
+        let document = XMLDocument()
+
+        document.addChild(toXML(node: root))
+        self.data = document.xmlData(options: [.nodeCompactEmptyElement, .nodePrettyPrint, .documentTidyXML])
+    }
+
+
+    /// Recursive function that iterates through all the child nodes and assigns attribute values
+    /// - Parameter node: parent node element
+    /// - Returns: XMLElement of the parent element with all children XMLElements appended.
+    private func toXML(node:Node<Element>) -> XMLElement {
+
+        let branchElement = XMLElement(name: node.element[keyPath: property])
+
+        for (attributeName, attributeValue) in attributes {
+
+            if let value:String = node.element[keyPath: attributeValue] {
+                    let attributeNode:XMLNode = XMLNode.attribute(
+                        withName: attributeName,
+                        stringValue: value
+                    ) as! XMLNode
+                    branchElement.addAttribute(attributeNode)
+                }
+        }
+
+        for childNode in node.children {
+            branchElement.addChild(toXML(node: childNode))
+        }
+
+        return branchElement
+    }
+
+
+    /// For testing purposes only, saves data to test.xml in document directory.
+    public func save() {
+        do {
+            var url = try FileManager.default.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: true)
+            url.appendPathComponent("test.xml")
+            print(url.relativePath)
+            FileManager.default.createFile(atPath: url.relativePath, contents: self.data)
+        } catch {
+            print(error.localizedDescription)
+        }
+    }
+}

Tests/TreeTests/XMLTreeTests.swift

@@ -0,0 +1,40 @@
+//
+//  XMLTreeTests.swift
+//
+//
+//  Created by joshydotpoo on 3/10/24.
+//
+
+import Foundation
+import XCTest
+@testable import Tree
+
+final class XMLTreeTests: XCTestCase {
+
+    func testNilAttribute() {
+        let root = Node(TestElement(name: "root"))
+        root.append(child: Node(TestElement(name: "child")))
+        let son = Node(TestElement(name: "child", nickName: "son"))
+        root.append(child: son)
+        son.append(child: Node(TestElement(name: "grandchil", nickName: "grandson")))
+
+        for node in root.depthFirst {
+            node.element.nickName = "testing"
+        }
+
+        let xmltree = XMLTree(root: root, using: \TestElement.id, assigning: ["nickname": \TestElement.nickName])
+        xmltree.save()
+
+    }
+
+    struct TestElement: Identifiable {
+        var id: String
+        var nickName:String?
+
+        init(name: String, nickName: String? = nil) {
+            self.id = name
+            self.nickName = nickName
+        }
+    }
+}
+