Setting Up Your Development Environment

Which editor you use depends on what you're building:

• Xcode (macOS) — Apple's IDE, required for iPhone, iPad, and Mac apps. It includes a code editor, the interface previews, simulators, a debugger, and performance tools.
• Visual Studio Code with the official Swift extension (from the Swift project) — free and cross-platform, with autocomplete, inline errors, debugging, and test running. A good choice for learning the language on Linux or Windows, and for command-line and server code.

For the lessons in Level 1 and Level 2, you only need a way to run .swift files. Create a folder for your practice files and open it in your editor.

Playgrounds

Xcode has playgrounds: files that run your code as you type and show each line's result in a side panel. Create one with File → New → Playground. They're excellent for experimenting with the examples in these lessons.

The REPL

Running swift repl in a terminal (on Linux and macOS) starts an interactive session where you type one line at a time:

$ swift repl
  1> let x = 2 + 3
x: Int = 5
  2> :quit