Swift with Copilot: Hello World in VSCode

First Swift program in VS Code. Install Swift, install the VS Code Swift extension, write print("Hello, World!"), run with swift hello.swift. Copilot autocompletes from a comment — but for one line, you barely need it.

This is the orientation episode for the series. Get Swift running outside Xcode, see Copilot fire off a suggestion, and confirm everything works.

Setup: Swift on macOS

# Swift ships with Xcode. If you have Xcode installed:
swift --version
# Apple Swift version 5.10 ...

# If not, install command-line tools (~3 GB):
xcode-select --install

For Linux, download from swift.org.

VS Code setup

Install the Swift extension (by Swift Server Work Group). It provides:

• Syntax highlighting.
• LSP integration via sourcekit-lsp.
• "Run Swift File" command.
• Debugging support.

Open VS Code, install the Swift extension, install the GitHub Copilot extension, and sign in.

The Copilot prompt

// Print "Hello, World!" to the console

Copilot completes:

// Print "Hello, World!" to the console
print("Hello, World!")

Save as hello.swift. Run:

swift hello.swift
# Hello, World!

swift script.swift runs a Swift file directly — no compilation step needed for one-off scripts. Internally, Swift compiles to a binary in a temp dir, runs it, deletes it.

What the line does

print("Hello, World!")

• print(_:) is Swift's standard output function.
• The argument is a string literal — Swift uses double quotes only.
• Default appends a newline; pass terminator: "" to suppress.

print("No newline", terminator: "")
print(" — same line")

Multiple arguments

print("A", "B", "C")
// A B C — separated by spaces by default

print("A", "B", "C", separator: "-")
// A-B-C

separator: and terminator: are the two named parameters.

Building a binary

For real apps, you'd use Swift Package Manager:

mkdir hello && cd hello
swift package init --type executable
swift run
# Hello, world!

swift package init --type executable scaffolds a Package.swift, Sources/hello/main.swift, etc. swift run builds and runs.

For now, single-file .swift scripts are fine.

Why VS Code instead of Xcode?

• Speed. VS Code starts in 1 second; Xcode in 10+.
• Familiar if you write JS/Python/Go in VS Code already.
• Copilot integrates everywhere.
• Cross-platform — same setup on Linux.

For iOS/macOS app development, you still need Xcode (Storyboards, SwiftUI previews, Simulator, signing). For Swift learning and server-side Swift, VS Code is fine.

Other ways to run Swift

# REPL
swift
> print("Hello")
> :quit

# Inline expression
swift -e 'print(1 + 2)'    # 3

# Swift script with arguments
swift hello.swift arg1 arg2

# As a shebang script
cat > hello.sh <<'EOF'
#!/usr/bin/env swift
print("Hello, World!")
EOF
chmod +x hello.sh
./hello.sh

#!/usr/bin/env swift makes a Swift file executable. Slow startup, but useful for quick scripts.

Common stumbles

swift: command not found. Xcode CLI tools missing. xcode-select --install.

LSP not working in VS Code. Open command palette → "Swift: Restart Language Server."

Print without newline using \n? print(...) already adds a newline; \n inside the string adds an extra. Pass terminator: "" to suppress the auto newline.

Single quotes. Swift requires double quotes for strings. 'hello' errors.

println from Swift 1.x. Removed. Just print.

What's next

Episode 2: Create a list of 5 random numbers. Arrays, Int.random(in:), map.

Recap

swift file.swift runs a single file. print("...") for output; separator: and terminator: named args. VS Code + Swift extension + Copilot is the modern setup outside Xcode. Use Swift Package Manager (swift package init) for real projects. Make scripts executable with #!/usr/bin/env swift + chmod +x.

Next episode: a list of 5 random numbers.