# Polka
A [dot](https://en.wikipedia.org/wiki/DOT_(graph_description_language)) language parser for Rust; based on [Parser Expression Grammar (PEG)](https://en.wikipedia.org/wiki/Parsing_expression_grammar) using the excellent [pest](http://pest.rs) crate as the underpinning.

![](logo.png)

---
### Usage (as a Rust Library)

0. Add this to your `Cargo.toml`:
  ```toml
    [dependencies]
    rand = "0.6"
  ```

1. Call the `parser` function by passing an input `String`

  ```rust
    extern crate polka;
    use polka::parse;

    fn main() {
      let input = "digraph { a -> b -> c }".to_string();
      println!("Polka AST\n: {:?}", parse(input).unwrap());
    }

    // Polka AST: 
    // Graph {
    //     strict: false,
    //     graph_type: Some(
    //         Digraph,
    //     ),
    //     id: None,
    //     statements: [
    //         EdgeStatement(
    //             EdgeStatement {
    //                 edge: NodeId(
    //                     NodeId {
    //                         node_id: "a",
    //                         port: None,
    //                     },
    //                 ),
    //                 edge_rhs_list: [
    //                     EdgeRhs {
    //                         edge_op: Arrow,
    //                         edge: NodeId(
    //                             NodeId {
    //                                 node_id: "b",
    //                                 port: None,
    //                             },
    //                         ),
    //                     },
    //                     EdgeRhs {
    //                         edge_op: Arrow,
    //                         edge: NodeId(
    //                             NodeId {
    //                                 node_id: "c",
    //                                 port: None,
    //                             },
    //                         ),
    //                     },
    //                 ],
    //                 attributes: None,
    //             },
    //         ),
    //     ],
    // }
  ```

--- 
### Known Limitations:

1. HTML ids are currently not supported.

### License
[MIT](./LICENSE)