sipha-tree 0.3.0

# sipha-tree

[![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
[![Repository](https://img.shields.io/badge/github-sipha-blue)](https://github.com/NyalephTheCat/sipha)
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[![docs.rs](https://docs.rs/sipha-tree/badge.svg)](https://docs.rs/sipha-tree)

CST and AST construction for sipha - arena allocation, node types, and lowering.

## Overview

`sipha-tree` provides the core data structures for representing Concrete Syntax Trees (CSTs) and utilities for lowering them into Abstract Syntax Trees (ASTs).

## Features

- **NodeArena**: Efficient arena-based allocation for CST nodes
- **CstNode**: Fundamental building block of the CST
- **CstKind**: Enum representing different node types (Token, Rule, Trivia, Error)
- **NodeChildren**: Compact representation for node children
- **LowerCtx**: Context for AST lowering operations
- **AstNode**: Trait for AST nodes to be lowered from CST

## Quick Start

Add `sipha-tree` to your `Cargo.toml`:

```toml
[dependencies]
sipha-tree = "0.1.1"
```

## Example

```rust
use sipha_core::traits::{TokenKind, RuleId};
use sipha_tree::{NodeArena, RawNodeId, CstNode, CstKind, NodeChildren};
use sipha_core::span::Span;

#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
enum MyToken { Ident, Number }
impl TokenKind for MyToken { fn is_trivia(&self) -> bool { false } }

#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
enum MyRule { Expr, Term }
impl RuleId for MyRule {}

let mut arena = NodeArena::<MyToken, MyRule, RawNodeId>::new();
let num_node = arena.alloc(CstNode::create(
    CstKind::Token(MyToken::Number),
    Span::new(0, 5),
    NodeChildren::new(),
));
let expr_node = arena.alloc(CstNode::create(
    CstKind::Rule(MyRule::Expr),
    Span::new(0, 5),
    NodeChildren::from_iter(vec![num_node]),
));

assert!(arena.get(expr_node).is_some());
```

## License

This project is licensed under the MIT License - see the [LICENSE](../LICENSE) file for details.