Added SPM support

Echo.xcodeproj/project.pbxproj

@@ -141,7 +141,8 @@
 				2DB496B01B5D37470012D92A /* extensions */,
 				2DBC9BFC1B558FBD00F15967 /* Supporting Files */,
 			);
-			path = Echo;
+			name = Echo;
+			path = Sources/Echo;
 			sourceTree = "<group>";
 		};
 		2DBC9BFC1B558FBD00F15967 /* Supporting Files */ = {
@@ -264,6 +265,7 @@
 			developmentRegion = English;
 			hasScannedForEncodings = 0;
 			knownRegions = (
+				English,
 				en,
 				Base,
 			);
@@ -451,7 +453,7 @@
 				DYLIB_COMPATIBILITY_VERSION = 1;
 				DYLIB_CURRENT_VERSION = 1;
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
-				INFOPLIST_FILE = Echo/Info.plist;
+				INFOPLIST_FILE = Sources/Echo/Info.plist;
 				INSTALL_PATH = "$(LOCAL_LIBRARY_DIR)/Frameworks";
 				IPHONEOS_DEPLOYMENT_TARGET = 11.4;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
@@ -472,7 +474,7 @@
 				DYLIB_COMPATIBILITY_VERSION = 1;
 				DYLIB_CURRENT_VERSION = 1;
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
-				INFOPLIST_FILE = Echo/Info.plist;
+				INFOPLIST_FILE = Sources/Echo/Info.plist;
 				INSTALL_PATH = "$(LOCAL_LIBRARY_DIR)/Frameworks";
 				IPHONEOS_DEPLOYMENT_TARGET = 11.4;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";

Package.swift

@@ -0,0 +1,27 @@
+// swift-tools-version: 5.7
+// The swift-tools-version declares the minimum version of Swift required to build this package.
+
+import PackageDescription
+
+let package = Package(
+    name: "Echo",
+    products: [
+        // Products define the executables and libraries a package produces, and make them visible to other packages.
+        .library(
+            name: "Echo",
+            targets: ["Echo"]),
+    ],
+    dependencies: [
+        // Dependencies declare other packages that this package depends on.
+        // .package(url: /* package url */, from: "1.0.0"),
+    ],
+    targets: [
+        // Targets are the basic building blocks of a package. A target can define a module or a test suite.
+        // Targets can depend on other targets in this package, and on products in packages this package depends on.
+        .target(
+            name: "Echo",
+            dependencies: [],
+            exclude: ["Echo.h", "Info.plist"]
+        ),
+    ]
+)

Echo/controllers/input_accessory_controller.swift → Sources/Echo/controllers/input_accessory_controller.swift

@@ -1,6 +1,6 @@
 import UIKit
 
-public protocol InputAccessoryControllerDelegate: class {
+public protocol InputAccessoryControllerDelegate: AnyObject {
 
   /// Called whenever the keyboard frame changes
   ///

Echo/controllers/keyboard_layout_guide.swift → Sources/Echo/controllers/keyboard_layout_guide.swift

@@ -1,3 +1,5 @@
+import UIKit
+
 open class KeyboardLayoutGuide: UILayoutGuide {
 
   lazy var heightConstraint: NSLayoutConstraint = {

Echo/data_structures/input_accessory_controller_behaviours.swift → Sources/Echo/data_structures/input_accessory_controller_behaviours.swift

@@ -20,6 +20,6 @@ public struct InputAccessoryControllerBehaviours: OptionSet {
     self.rawValue = rawValue
   }
 
-  public static let allZeros = InputAccessoryControllerBehaviours(rawValue: 0)
+    public static let allZeros = InputAccessoryControllerBehaviours([])
   public static let adjustContentOffset = InputAccessoryControllerBehaviours(rawValue: 0b1)
 }

Echo/extensions/ui_responder_echo.swift → Sources/Echo/extensions/ui_responder_echo.swift

@@ -1,4 +1,5 @@
 import Foundation
+import UIKit
 
 var DidNotResignFirstResponder = "didNotResignFirstResponder"
 

Tests/echoTests/echoTests.swift

@@ -0,0 +1,11 @@
+import XCTest
+@testable import echo
+
+final class echoTests: XCTestCase {
+    func testExample() throws {
+        // This is an example of a functional test case.
+        // Use XCTAssert and related functions to verify your tests produce the correct
+        // results.
+        XCTAssertEqual(echo().text, "Hello, World!")
+    }
+}