Rust Tree-sitter

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Rust bindings to the Tree-sitter parsing library.

Basic Usage

First, create a parser:

```rust use tree_sitter::{Parser, Language};

let mut parser = Parser::new(); ```

Add the cc crate to your Cargo.toml under [build-dependencies]:

toml [build-dependencies] cc="*"

Then, add a language as a dependency:

toml [dependencies] tree-sitter = "0.20.10" tree-sitter-rust = "0.20.3"

To then use a language, you assign them to the parser.

rust parser.set_language(tree_sitter_rust::language()).expect("Error loading Rust grammar");

Now you can parse source code:

```rust let sourcecode = "fn test() {}"; let tree = parser.parse(sourcecode, None).unwrap(); let rootnode = tree.rootnode();

asserteq!(rootnode.kind(), "sourcefile"); asserteq!(rootnode.startposition().column, 0); asserteq!(rootnode.end_position().column, 12); ```

Editing

Once you have a syntax tree, you can update it when your source code changes. Passing in the previous edited tree makes parse run much more quickly:

```rust let newsourcecode = "fn test(a: u32) {}"

tree.edit(InputEdit { startbyte: 8, oldendbyte: 8, newendbyte: 14, startposition: Point::new(0, 8), oldendposition: Point::new(0, 8), newendposition: Point::new(0, 14), });

let newtree = parser.parse(newsource_code, Some(&tree)); ```

Text Input

The source code to parse can be provided either as a string, a slice, a vector, or as a function that returns a slice. The text can be encoded as either UTF8 or UTF16:

```rust // Store some source code in an array of lines. let lines = &[ "pub fn foo() {", " 1", "}", ];

// Parse the source code using a custom callback. The callback is called // with both a byte offset and a row/column offset. let tree = parser.parsewith(&mut |byte: u32, position: Point| -> &[u8] { let row = position.row as usize; let column = position.column as usize; if row < lines.len() { if column < lines[row].asbytes().len() { &lines[row].asbytes()[column..] } else { "\n".as_bytes() } } else { &[] } }, None).unwrap();

asserteq!( tree.rootnode().tosexp(), "(sourcefile (functionitem (visibilitymodifier) (identifier) (parameters) (block (number_literal))))" ); ```