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This Rust library implements a Surging Object DiGraph (SODG) for
[reo](https://github.com/objectionary/reo) virtual machine for
[EO](https://www.eolang.org) programs. The graph is "surging" because
it automatically behind the scene deletes vertices and edges from itself,
which is also known as "garbage collection" mechanism. A vertex gets deleted
right after the data it contains is read _and_ no other vertices transitively point
to it.
Here is how you can create a di-graph:
```rust
use sodg::Sodg;
use sodg::Hex;
let mut g = Sodg::empty();
g.add(0)?; // add a vertex no.0
g.add(1)?; // add a vertex no.1
g.bind(0, 1, "foo")?; // connect v0 to v1 with label "foo"
g.put(1, Hex::from_str_bytes("Hello, world!"))?; // attach data to v1
```
Then, you can find a vertex by the label of an edge departing from another vertex:
```rust
let id = g.kid(0, "foo")?;
assert_eq!(1, id);
```
Then, you can find all kids of a vertex:
```rust
let kids: Vec<(String, String, u32)> = g.kids(0);
assert_eq!("foo", kids[0].0);
assert_eq!("bar", kids[0].1);
assert_eq!(1, kids[0].2);
```
Then, you can read the data of a vertex:
```rust
let hex: Hex = g.data(1)?;
let num: i64 = hex.to_i64()?;
assert_eq!(42, num);
```
Then, you can print the graph:
```rust
println!("{:?}", g);
```
Using `merge()`, you can merge two graphs together, provided they are trees.
Using `save()` and `load()`, you can serialize and deserialize the graph.
Using `to_xml()` and `to_dot()`, you can print it to
[XML](https://en.wikipedia.org/wiki/XML) and
[DOT](https://graphviz.org/doc/info/lang.html).
Using `slice()` and `slice_some()`, you can take a part/slice
of the graph (mostly for debugging purposes).
Read [the documentation](https://docs.rs/sodg/latest/sodg/).
## How to Contribute
First, install [Rust](https://www.rust-lang.org/tools/install) and then:
```bash
$ cargo test -vv
```
If everything goes well, fork repository, make changes, send us a [pull request](https://www.yegor256.com/2014/04/15/github-guidelines.html).
We will review your changes and apply them to the `master` branch shortly,
provided they don't violate our quality standards. To avoid frustration,
before sending us your pull request please run `cargo test` again. Also,
run `cargo fmt` and `cargo clippy`.