add the tutorial example code

Author: sebsto

Examples/Tutorial/.gitignore

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+.DS_Store
+/.build
+/Packages
+xcuserdata/
+DerivedData/
+.swiftpm/configuration/registries.json
+.swiftpm/xcode/package.xcworkspace/contents.xcworkspacedata
+.netrc

Examples/Tutorial/Package.swift

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+// swift-tools-version: 6.0
+// The swift-tools-version declares the minimum version of Swift required to build this package.
+
+import PackageDescription
+
+let package = Package(
+    name: "Palindrome",
+    platforms: [ .macOS(.v15)],
+    dependencies: [
+        .package(url: "https://github.com/swift-server/swift-aws-lambda-runtime.git", branch: "main"),
+    ],
+    targets: [
+        // Targets are the basic building blocks of a package, defining a module or a test suite.
+        // Targets can depend on other targets in this package and products from dependencies.
+        .executableTarget(
+            name: "Palindrome",
+            dependencies: [
+                .product(name: "AWSLambdaRuntime", package: "swift-aws-lambda-runtime"),
+            ]),
+    ]
+)
+
+import struct Foundation.URL
+
+if let localDepsPath = Context.environment["LAMBDA_USE_LOCAL_DEPS"],
+    localDepsPath != "",
+    let v = try? URL(fileURLWithPath: localDepsPath).resourceValues(forKeys: [.isDirectoryKey]),
+    v.isDirectory == true
+{
+    // when we use the local runtime as deps, let's remove the dependency added above
+    let indexToRemove = package.dependencies.firstIndex { dependency in
+        if case .sourceControl(
+            name: _,
+            location: "https://github.com/swift-server/swift-aws-lambda-runtime.git",
+            requirement: _
+        ) = dependency.kind {
+            return true
+        }
+        return false
+    }
+    if let indexToRemove {
+        package.dependencies.remove(at: indexToRemove)
+    }
+
+    // then we add the dependency on LAMBDA_USE_LOCAL_DEPS' path (typically ../..)
+    print("[INFO] Compiling against swift-aws-lambda-runtime located at \(localDepsPath)")
+    package.dependencies += [
+        .package(name: "swift-aws-lambda-runtime", path: localDepsPath)
+    ]
+}

Examples/Tutorial/Sources/main.swift

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+import AWSLambdaRuntime
+
+// the data structure to represent the input parameter
+struct Request: Decodable {
+    let text: String
+}
+
+// the data structure to represent the response parameter
+struct Response: Encodable {
+    let text: String
+    let isPalindrome: Bool
+    let message: String
+}
+
+// the business function
+func isPalindrome(_ text: String) -> Bool {
+    let cleanedText = text.lowercased().filter { $0.isLetter }
+    return cleanedText == String(cleanedText.reversed())
+}
+
+// the lambda handler function
+let runtime = LambdaRuntime {
+    (event: Request, context: LambdaContext) -> Response in
+    
+    let result = isPalindrome(event.text)
+    return Response(text: event.text, isPalindrome: result, message: "Your text is \(result ? "a" : "not a") palindrome")
+}
+
+// start the runtime
+try await runtime.run()