Various improvements

Package.swift

@@ -4,9 +4,9 @@ import PackageDescription
 let package = Package(
 	name: "OPML",
 	platforms: [
-		.iOS(.v13),
-		.macOS(.v10_15),
-		.tvOS(.v13),
+		.iOS(.v14),
+		.macOS(.v11),
+		.tvOS(.v14),
 	],
 	products: [
 		.library(name: "OPML", targets: ["OPML"])

Sources/OPML/Conveniences/OPMLEntry+Values.swift

@@ -0,0 +1,17 @@
+import Foundation
+
+public extension OPMLEntry {
+    func attributeBoolValue(_ name: String) -> Bool? {
+        guard let value = attributes?.first(where: { $0.name == name })?.value else { return nil }
+        return value == "true"
+    }
+
+    func attributeStringValue(_ name: String) -> String? {
+        return attributes?.first(where: { $0.name == name })?.value
+    }
+
+    func attributeUUIDValue(_ name: String) -> UUID? {
+        guard let value = attributes?.first(where: { $0.name == name })?.value else { return nil }
+        return UUID(uuidString: value)
+    }
+}

Sources/OPML/Exporter/Exporter.swift

@@ -2,17 +2,17 @@ import Foundation
 import Html
 
 public extension OPML {
-
 	var xml: String {
 		render(document)
 	}
 
-	func xml(indented: Bool) -> String {
-		if indented {
-			return debugRender(document, config: Config.pretty)
-		}
-		return xml
-	}
+    // TODO: Reintroduce indentation when bugs are fixed. Currently doesn't escape attribute values.
+//	func xml(indented: Bool) -> String {
+//        if indented {
+//			return debugRender(document, config: Config.pretty)
+//		}
+//		return xml
+//	}
 
 	private static let dateFormatter = DateFormatter.iso8601
 
@@ -53,11 +53,9 @@ public extension OPML {
 		}
 		return .head(children)
 	}
-
 }
 
 extension OPMLEntry {
-
 	var htmlAttributes: [(String, String)] {
 		var htmlAttributes: [(String, String)] = attributes?.compactMap {
 			guard !$0.value.isEmpty else { return nil }
@@ -70,5 +68,10 @@ extension OPMLEntry {
 	var node: Node {
 		.outline(attributes: htmlAttributes, children?.map { $0.node } ?? [])
 	}
+}
 
+public extension OPMLEntry {
+	var xml: String {
+		render(node)
+	}
 }

Sources/OPML/Models/OPMLEntry.swift

@@ -44,5 +44,4 @@ public struct OPMLEntry: Codable, Hashable {
 		] + (attributes ?? [])
 		children = nil
 	}
-
 }

Sources/OPML/Transfer/OPML+Transferable.swift

@@ -0,0 +1,43 @@
+import SwiftUI
+import UniformTypeIdentifiers
+
+enum TransferError: Error {
+    case importFailed
+}
+
+@available(iOS 16.0, macOS 13.0, *)
+extension OPML: Transferable {
+    public static var transferRepresentation: some TransferRepresentation {
+        FileRepresentation(contentType: .fileURL,
+                           shouldAttemptToOpenInPlace: false) { opml in
+            let resultURL = FileManager.default.temporaryDirectory
+                .appendingPathComponent(opml.title ?? UUID().uuidString)
+                .appendingPathExtension("opml")
+            if FileManager.default.fileExists(atPath: resultURL.path) {
+                try FileManager.default.removeItem(at: resultURL)
+            }
+            let data = opml.xml.data(using: .utf8) ?? Data()
+            try data.write(to: resultURL, options: [.atomic])
+            return SentTransferredFile(resultURL, allowAccessingOriginalFile: true)
+        } importing: { opmlFile in
+            let data = try Data(contentsOf: opmlFile.file, options: [.uncached])
+            return (try? OPML(data)) ?? OPML(entries: [])
+        }
+
+        DataRepresentation(contentType: .opml) { opml in
+            opml.xml.data(using: .utf8) ?? Data()
+        } importing: { data in
+            return (try? OPML(data)) ?? OPML(entries: [])
+        }
+
+        DataRepresentation(contentType: .utf8PlainText) { opml in
+            opml.xml.data(using: .utf8) ?? Data()
+        } importing: { data in
+            return (try? OPML(data)) ?? OPML(entries: [])
+        }
+    }
+}
+
+extension UTType {
+    static let opml = UTType(exportedAs: "public.opml", conformingTo: .xml)
+}

Sources/OPML/Transfer/OPMLFile.swift

@@ -0,0 +1,32 @@
+import Foundation
+import SwiftUI
+import UniformTypeIdentifiers
+
+public struct OPMLFile: FileDocument {
+    // tell the system we support only plain text
+    public static var readableContentTypes = [UTType(exportedAs: "public.opml"), UTType.plainText]
+
+    public var title = ""
+
+    // by default our document is empty
+    public var text = ""
+
+    // a simple initializer that creates new, empty documents
+    public init(opml: OPML) {
+        text = opml.xml
+        title = opml.title ?? ""
+    }
+
+    // this initializer loads data that has been saved previously
+    public init(configuration: ReadConfiguration) throws {
+        if let data = configuration.file.regularFileContents {
+            text = String(decoding: data, as: UTF8.self)
+        }
+    }
+
+    // this will be called when the system wants to write our data to disk
+    public func fileWrapper(configuration: WriteConfiguration) throws -> FileWrapper {
+        let data = Data(text.utf8)
+        return FileWrapper(regularFileWithContents: data)
+    }
+}