Syntax Diagrams

Python library for rendering syntax diagrams (a.k.a. railroad diagrams).

Features

• Automatic line wrapping, keeping width of the diagram below limits.

• Clever rendering of optionals, avoiding clutter where possible.

• Automatic right-to-left rendering in one-or-more loops.

• Producing SVGs or ASCII art.

• Try it in your browser.

• See also: sphinx-syntax, a Sphinx plugin for documenting grammars.

Example output

This is a part of SQLite’s grammar rendered with this library:

Table of contents

• Quickstart
  • Installation
  • Describing diagrams
  • Rendering diagrams
• Describing diagrams
  • Using YAML or Python literals
  • Using constructors
  • Line breaks and wrapping
• Rendering diagrams
  • render_svg()
  • render_text()
  • Settings
  • Errors
• Advanced API
  • Customizing hyperlink resolution
  • Customizing text measure