https://github.com/lukaslueg/railroad

A library to produce syntax diagrams as Scalable Vector Graphics
https://github.com/lukaslueg/railroad

Last synced: 28 days ago
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A library to produce syntax diagrams as Scalable Vector Graphics

• Host: GitHub
• URL: https://github.com/lukaslueg/railroad
• Owner: lukaslueg
• License: mit
• Created: 2018-08-12T14:35:51.000Z (over 6 years ago)
• Default Branch: master
• Last Pushed: 2024-07-26T18:21:24.000Z (9 months ago)
• Last Synced: 2025-03-29T13:09:01.377Z (about 1 month ago)
• Language: Rust
• Size: 642 KB
• Stars: 150
• Watchers: 5
• Forks: 7
• Open Issues: 8
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
### A library to create syntax ("railroad") diagrams as Scalable Vector Graphics (SVG).

[![Build status](https://github.com/lukaslueg/railroad/actions/workflows/check.yml/badge.svg)](https://github.com/lukaslueg/railroad/actions/workflows/check.yml)

[![Crates.io Version](https://img.shields.io/crates/v/railroad.svg)](https://crates.io/crates/railroad)

[![Docs](https://docs.rs/railroad/badge.svg)](https://docs.rs/railroad)

**[Live demo](https://lukaslueg.github.io/macro_railroad_wasm_demo/)** ([code](https://github.com/lukaslueg/macro_railroad_wasm))

**[Some examples](https://htmlpreview.github.io/?https://github.com/lukaslueg/railroad_dsl/blob/master/examples/example_diagrams.html)** using a small [DSL of it's own](https://github.com/lukaslueg/railroad_dsl).

Railroad diagrams are a way to represent context-free grammar. Every diagram has exactly one starting- and end-point; everything that belongs to the described language is represented by one of the possible paths between those points.

Using this library, diagrams are created using primitives which implement `Node`. Primitives are combined into more complex structures by wrapping simple elements into more complex ones.

```rust

use railroad::*;

let mut seq = Sequence::default();

seq.push(Box::new(Start) as Box)

   .push(Box::new(Terminal::new("BEGIN".to_owned())))

   .push(Box::new(NonTerminal::new("syntax".to_owned())))

   .push(Box::new(End));

let mut dia = Diagram::new(seq);

dia.add_element(svg::Element::new("style")

                .set("type", "text/css")

                .text(DEFAULT_CSS));

println!("{}", dia);

```

![diagram for create table sql syntax](https://raw.githubusercontent.com/lukaslueg/railroad/master/examples/create_table_stmt.jpeg)

When adding new `Node`-primitives to this library, you may find `examples/visual.rs` come in handy to quickly generate special-cases and check if they render properly. Use the `visual-debug` feature to add guide-lines to the rendered diagram and extra information to the SVG's code.