# SwiftFormat — Opinionated Swift Code Formatter

> A command-line tool and Xcode extension for automatically formatting Swift code according to configurable style rules.

## Install

Save as a script file and run:

# SwiftFormat — Opinionated Swift Code Formatter

## Quick Use
```bash
brew install swiftformat

# Format all Swift files in a directory
swiftformat .

# Preview changes without writing
swiftformat --dryrun .

# Use with specific rules
swiftformat --rules indent,braces,trailingCommas .
```

## Introduction
SwiftFormat is an opinionated code formatter for Swift that enforces a consistent style across your codebase. It rewrites Swift files in place based on a comprehensive set of configurable rules covering indentation, spacing, brace placement, import sorting, and dozens of other style preferences.

## What SwiftFormat Does
- Automatically reformats Swift source files to match configured style rules
- Provides 70+ individual formatting rules that can be enabled or disabled
- Runs as a CLI tool, Xcode source editor extension, or SPM build plugin
- Supports a .swiftformat configuration file for project-wide settings
- Integrates with Git hooks and CI pipelines for automated enforcement

## Architecture Overview
SwiftFormat parses Swift source into a token stream using its own lightweight tokenizer (not the full Swift compiler). It then applies a sequence of formatting rules as token-level transformations. Each rule is an independent function that scans and modifies the token array. Rules are applied in a defined order, with multiple passes to resolve dependencies between rules. The formatted token stream is then serialized back to source text.

## Self-Hosting & Configuration
- Install via Homebrew: `brew install swiftformat`
- Or via Mint, CocoaPods, or as an SPM package plugin
- Create a .swiftformat file to configure rules, indentation, and excluded paths
- Add as a Git pre-commit hook for automatic formatting on commit
- Install the Xcode Source Editor Extension for in-editor formatting

## Key Features
- Token-based formatting that preserves comments and non-standard syntax
- Configurable indentation (tabs or spaces with custom width)
- Import sorting, redundant keyword removal, and trailing comma insertion
- Xcode extension for formatting selections or entire files within the editor
- Lint mode (--lint) that reports violations without modifying files for CI use

## Comparison with Similar Tools
- **swift-format (Apple)** — Apple's official formatter; fewer rules and less configurable
- **SwiftLint** — focuses on linting and warnings rather than auto-formatting; complementary tool
- **Prettier** — multi-language formatter; does not support Swift
- **clang-format** — C/C++/Objective-C formatter; no Swift support
- **Xcode auto-indentation** — basic indentation only; no comprehensive style enforcement

## FAQ
**Q: What is the difference between SwiftFormat and SwiftLint?**
A: SwiftFormat rewrites code to match style rules. SwiftLint reports violations and can auto-correct some issues. Many teams use both together.

**Q: Can I disable specific rules for parts of my code?**
A: Yes. Use `// swiftformat:disable <rule>` and `// swiftformat:enable <rule>` comments to toggle rules inline.

**Q: Does SwiftFormat support Swift 6 and strict concurrency?**
A: Yes. The tokenizer handles modern Swift syntax including actors, async/await, and parameter packs.

**Q: Will SwiftFormat change the behavior of my code?**
A: The formatter only changes whitespace, formatting, and certain redundant syntax. It does not alter logic or semantics. The --dryrun flag lets you preview all changes before applying.

## Sources
- https://github.com/nicklockwood/SwiftFormat
- https://github.com/nicklockwood/SwiftFormat/blob/main/Rules.md

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Source: https://tokrepo.com/en/workflows/asset-ef0019e0
Author: Script Depot