diff --git a/1_single_executable/CMakeLists.txt b/1_single_executable/CMakeLists.txt
index 05d4d5d..08d9393 100644
--- a/1_single_executable/CMakeLists.txt
+++ b/1_single_executable/CMakeLists.txt
@@ -9,4 +9,4 @@ cmake_minimum_required(VERSION 3.22)
 
 project(hello LANGUAGES Swift)
 
-add_executable(hello hello.swift)
+add_executable(hello main.swift world.swift)
diff --git a/1_single_executable/hello.swift b/1_single_executable/main.swift
similarity index 93%
rename from 1_single_executable/hello.swift
rename to 1_single_executable/main.swift
index 921f562..ea5c6f2 100644
--- a/1_single_executable/hello.swift
+++ b/1_single_executable/main.swift
@@ -9,4 +9,5 @@
 //
 //===----------------------------------------------------------------------===//
 
-print("Hello, world!")
+
+print("Hello, \(world())!")
diff --git a/1_single_executable/world.swift b/1_single_executable/world.swift
new file mode 100644
index 0000000..57641f4
--- /dev/null
+++ b/1_single_executable/world.swift
@@ -0,0 +1,16 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift open source project
+//
+// Copyright (c) 2023 Apple Inc. and the Swift project authors.
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+//
+//===----------------------------------------------------------------------===//
+
+func world() -> String
+{
+  return "world"
+}
+