ryml: Rapid YAML Bindings for Rust

Rapid YAML/ryml is a C++ library to parse and emit YAML, and do it fast. The ryml crate provides fairly thin but safe (I think) FFI bindings to bring this power to Rust.

This crate is currently is early, early alpha. Not all of the C++ API is covered, and some of it probably will not be, but the core functionality is all in place (indeed, much more than the official Python bindings).

Usage

A basic example of how to use this crate:

use ryml::Tree;

static SRC: &str = r#"
Hello: World
Names: [Caleb, Voronwe, 'Nicene Nerd']
Credo: !!apostolicus
 - in Deum, Patrem omnipotentem
 - et in Iesum Christum, Filium eius unicum
 - in Spiritum Sanctum
"#;

let mut tree = Tree::parse(SRC)?;
assert_eq!(10, tree.len());

// First, the low-level, index-based API
let root_id = tree.root_id()?;
assert_eq!(root_id, 0);
assert_eq!(tree.num_children(root_id)?, 3);
for i in 0..tree.num_children(root_id)? {
  let child_id = tree.child_at(root_id, i)?;
  println!("{}", tree.key_scalar(child_id)?.scalar); // "Hello", "Names", "Credo"
}

// Next, the high-level, NodeRef API
let world = tree.root_ref()?.get("Hello")?;
assert_eq!(world.val()?, "World");
let credo = tree.root_ref()?.get("Credo")?;
assert!(credo.is_seq()?);
assert_eq!(credo.val_tag()?, "!!apostolicus");    
for node in credo.iter()? {
  println!("{}", node.val()?);
}

// Mutate the tree
{
   let mut root_ref_mut = tree.root_ref_mut()?;
   let mut credo = root_ref_mut.get_mut("Credo")?;
   let mut amen = credo.get_mut(3)?; // A new index
   amen.set_val("Amen")?;
}

// Serialize the tree back to a string
let new_text = tree.emit()?;

static END: &str = r#"Hello: World
Names:
 - Caleb
 - Voronwe
 - 'Nicene Nerd'
Credo: !!apostolicus
 - 'in Deum, Patrem omnipotentem'
 - 'et in Iesum Christum, Filium eius unicum'
 - in Spiritum Sanctum
 - Amen
"#;

assert_eq!(new_text, END);

For more usage information, see the full documentation.

Contributing

Issue tracker: https://github.com/NiceneNerd/ryml/issues
Source code: https://github.com/NiceneNerd/ryml

Some welcome to-dos:

• Anything that would improve error handling
• no_std support is an eventual goal
• Safety improvements
• Could definitely use more tests and such

License

This project is licensed under the GPLv3+ license. The original ryml library is licensed under the MIT license.