retab

A powerful multi-language code formatter that emphasizes tabs-first formatting, with native support for Protocol Buffers, HCL, and YAML files, plus additional support for external formatters like Terraform, Dart, and Swift.

Installation

go install github.com/walteh/retab/v2/cmd/retab@latest

Features

• Native Formatters:

  • Protocol Buffers (.proto files)
  • HashiCorp Configuration Language (HCL)
  • YAML (.yaml, .yml files)

• External Formatters:

  • Terraform (requires terraform CLI)
  • Dart (requires dart CLI)
  • Swift (requires swift-format)

• Tabs-First Approach: While the formatter respects your .editorconfig settings, it's designed with tabs in mind for better accessibility and consistent indentation.

Usage

Format a file using the fmt command:

# Auto-detect formatter based on file extension
retab fmt myfile.proto

# Explicitly specify formatter
retab fmt myfile.proto --formatter=proto
retab fmt myfile.hcl --formatter=hcl
retab fmt myfile.yaml --formatter=yaml
retab fmt myfile.tf --formatter=tf
retab fmt myfile.dart --formatter=dart
retab fmt myfile.swift --formatter=swift

Examples

Protocol Buffers

// Before formatting
service  MyService{rpc   MyMethod(MyRequest)   returns(MyResponse);}

// After formatting (with default tab indentation)
service MyService {
	rpc MyMethod(MyRequest) returns (MyResponse);
}

HCL

// Before formatting
resource "aws_instance" "example" {ami="ami-123456"
instance_type="t2.micro"
  tags={Name="example"}}

// After formatting (with default tab indentation)
resource "aws_instance" "example" {
	ami           = "ami-123456"
	instance_type = "t2.micro"
	tags = {
		Name = "example"
	}
}

YAML

# Before formatting
services:
  web:
    image:    nginx:latest
    ports:  
     - "80:80"
    volumes:
      - ./nginx.conf:/etc/nginx/nginx.conf:ro
    environment:
          DEBUG: 'true'
          API_KEY:     'secret'

# After formatting (with default tab indentation)
services:
	web:
		image: nginx:latest
		ports:
			- "80:80"
		volumes:
			- ./nginx.conf:/etc/nginx/nginx.conf:ro
		environment:
			DEBUG: 'true'
			API_KEY: 'secret'

Swift

// Before formatting
struct ContentView{
var body:some View{
Text("Hello, world!")
.padding()
}}

// After formatting (with default indentation)
struct ContentView {
    var body: some View {
        Text("Hello, world!")
            .padding()
    }
}

Configuration

retab uses .editorconfig for configuration. While designed with tabs in mind, it respects your project's settings. Here's a sample .editorconfig:

[*]
# common settings supported
indent_style = tab   # 'tab' or 'space'
indent_size = 4     # Size of indentation
max_line_length = 120          # Maximum line length for YAML files

# custom settings supported
trim_multiple_empty_lines = true  # Remove multiple blank lines
one_bracket_per_line = true  # Force brackets onto new lines

# yaml-specific settings
pad_line_comments = 2        # Padding spaces before line comments

If no .editorconfig is found, it defaults to:

• Tabs for indentation (recommended)
• Tab size of 4
• Trim multiple empty lines enabled
• One bracket per line enabled

Swift Formatting Note

When using Swift formatting with EditorConfig, indentation settings will only work correctly if your swift-format configuration has spaces=2 set as the indentation (which is the default). If you need different indentation settings, you'll need to modify your swift-format configuration file.

Why Tabs?

We believe in tabs-first formatting because:

• Better accessibility for developers using screen readers
• Allows each developer to set their preferred indentation width
• Smaller file sizes
• Clear and unambiguous indentation

Contributing

Contributions are welcome! Please feel free to submit a Pull Request. For major changes, please open an issue first to discuss what you would like to change.

License

This project is licensed under the Apache 2.0 License - see the LICENSE file for details.

Acknowledgments

• Adapted from protocompile for Protocol Buffer formatting
• Uses editorconfig-core-go for configuration
• Uses yamlfmt for YAML formatting