treesitter_types/codegen/
mod.rs

1pub mod emitter;
2pub mod grammar_ir;
3pub mod name_mangler;
4pub mod type_mapper;
5
6use proc_macro2::TokenStream;
7use std::path::Path;
8
9/// Generates a `TokenStream` of typed AST definitions from the contents of a `node-types.json`.
10pub fn generate(node_types_json: &str) -> Result<TokenStream, Error> {
11    let nodes = grammar_ir::parse_node_types(node_types_json)?;
12    let decisions = type_mapper::map_types(&nodes);
13    Ok(emitter::emit(&decisions))
14}
15
16/// Formats a `TokenStream` into pretty-printed Rust source code.
17pub fn format(tokens: &TokenStream) -> Result<String, Error> {
18    let file = syn::parse2(tokens.clone()).map_err(Error::Syn)?;
19    Ok(prettyplease::unparse(&file))
20}
21
22/// Reads a `node-types.json` file, generates typed AST code, and writes it to `$OUT_DIR`.
23///
24/// The generated code is formatted with `prettyplease` for readability.
25///
26/// Intended for use in `build.rs`:
27/// ```no_run
28/// treesitter_types::codegen::emit_to_out_dir("path/to/node-types.json").unwrap();
29/// ```
30///
31/// Then in `lib.rs`:
32/// ```ignore
33/// include!(concat!(env!("OUT_DIR"), "/treesitter_types_generated.rs"));
34/// ```
35pub fn emit_to_out_dir(node_types_path: impl AsRef<Path>) -> Result<(), Error> {
36    let node_types_path = node_types_path.as_ref();
37    let json = std::fs::read_to_string(node_types_path)
38        .map_err(|e| Error::Io(node_types_path.to_path_buf(), e))?;
39    let tokens = generate(&json)?;
40    let code = format(&tokens)?;
41
42    let out_dir = std::env::var("OUT_DIR").map_err(|_| Error::NoOutDir)?;
43    let out_path = Path::new(&out_dir).join("treesitter_types_generated.rs");
44    std::fs::write(&out_path, code).map_err(|e| Error::Io(out_path, e))?;
45
46    // Tell Cargo to re-run if the input changes
47    println!("cargo:rerun-if-changed={}", node_types_path.display());
48
49    Ok(())
50}
51
52#[derive(Debug, thiserror::Error)]
53pub enum Error {
54    #[error("failed to parse node-types.json: {0}")]
55    Json(#[from] serde_json::Error),
56
57    #[error("generated code is not valid Rust syntax: {0}")]
58    Syn(syn::Error),
59
60    #[error("I/O error on {0}: {1}")]
61    Io(std::path::PathBuf, #[source] std::io::Error),
62
63    #[error("OUT_DIR environment variable not set (are you running from build.rs?)")]
64    NoOutDir,
65}
treesitter_types/codegen/mod.rs

treesitter_types/codegen/
mod.rs
