Swift Development

Swift Development

Prerequisites

• macOS with Xcode 15+ installed (Xcode 16+ for Swift 6)
• Xcode Command Line Tools: xcode-select --install
• Verify: xcodebuild -version and swift --version

Quick Start

New Swift Package

# Use the included script for full setup
./scripts/new_package.sh MyLibrary --type library --ios --macos

# Or manually
swift package init --type library --name MyLibrary

Build and Test

# SPM packages
swift build
swift test

# Xcode projects
xcodebuild -workspace App.xcworkspace -scheme App \
    -destination 'platform=iOS Simulator,name=iPhone 15' build

# Use included script for common options
./scripts/run_tests.sh --parallel --coverage

Format and Lint

# Use included script
./scripts/format_and_lint.sh Sources/

# Check mode (CI)
./scripts/format_and_lint.sh --check

Simulator Management

# Use included script
./scripts/simulator.sh list
./scripts/simulator.sh boot "iPhone 15"
./scripts/simulator.sh screenshot
./scripts/simulator.sh dark

Core Workflows

Building iOS Apps

# Debug build for simulator
xcodebuild -workspace App.xcworkspace -scheme App \
    -destination 'platform=iOS Simulator,name=iPhone 15' \
    build

# Release archive
xcodebuild archive \
    -workspace App.xcworkspace -scheme App \
    -archivePath ./build/App.xcarchive \
    -configuration Release

# Export IPA (use templates from assets/ExportOptions/)
xcodebuild -exportArchive \
    -archivePath ./build/App.xcarchive \
    -exportPath ./build/export \
    -exportOptionsPlist assets/ExportOptions/app-store.plist

Testing

# All tests
xcodebuild test -workspace App.xcworkspace -scheme App \
    -destination 'platform=iOS Simulator,name=iPhone 15'

# Specific test
xcodebuild test -only-testing:AppTests/MyTestClass/testMethod

# With coverage
xcodebuild test -enableCodeCoverage YES \
    -resultBundlePath ./TestResults.xcresult

App Installation

# Install on booted simulator
xcrun simctl install booted ./Build/Products/Debug-iphonesimulator/App.app

# Launch
xcrun simctl launch booted com.company.app

Official Documentation

Reference Links (for humans)

These are Apple's official documentation links for manual browsing:

Note: Apple's documentation sites are JavaScript SPAs and cannot be fetched programmatically with WebFetch. Use GitHub-based sources below instead.

WebFetch-Compatible Sources (Raw GitHub URLs)

Always use raw.githubusercontent.com URLs — regular github.com URLs return garbled HTML/JSON.

Base URL prefix: https://raw.githubusercontent.com/apple

Swift Testing (/swift-testing/main/):

Other Swift Packages:

For Swift Evolution proposals, construct the raw URL from the proposal number: https://raw.githubusercontent.com/apple/swift-evolution/main/proposals/NNNN-proposal-name.md

Example: https://raw.githubusercontent.com/apple/swift-evolution/main/proposals/0409-access-level-on-imports.md

For directory discovery (finding proposal numbers, doc file names): use WebSearch instead of WebFetch — directory listings on GitHub are not parseable.

When to Fetch Documentation

Use WebFetch with raw GitHub URLs in these situations:

1. Swift Testing: When you need details on @Test, #expect, #require, traits, or parameterized tests
2. Swift Evolution: When checking accepted proposals for new language features
3. Framework Details: When implementing features from Apple's open-source Swift packages
4. Uncertainty: When you're unsure about current API patterns or best practices

URL conversion rule: Replace github.com/{owner}/{repo}/blob/{branch}/ with raw.githubusercontent.com/{owner}/{repo}/{branch}/

Fallback: If WebFetch fails on a raw URL, use WebSearch with the query site:github.com/apple {topic} to discover the correct file path, then construct the raw URL.

Example prompt for WebFetch: "Extract the main features, macros, and usage examples from this documentation"

Reference Files

Detailed documentation for specific topics:

Included Scripts

Asset Templates

Quick Reference

Essential Commands

Common Destinations

# iOS Simulator
-destination 'platform=iOS Simulator,name=iPhone 15'

# macOS
-destination 'platform=macOS'

# Generic iOS (for archives)
-destination 'generic/platform=iOS'