tree_sitter_wit/
lib.rs

1//! This crate provides Wit language support for the [tree-sitter][] parsing library.
2//!
3//! Typically, you will use the [language][language func] function to add this language to a
4//! tree-sitter [Parser][], and then use the parser to parse some code:
5//!
6//! ```
7//! let code = r#"
8//! "#;
9//! let mut parser = tree_sitter::Parser::new();
10//! parser.set_language(&tree_sitter_wit::language()).expect("Error loading Wit grammar");
11//! let tree = parser.parse(code, None).unwrap();
12//! assert!(!tree.root_node().has_error());
13//! ```
14//!
15//! [Language]: https://docs.rs/tree-sitter/*/tree_sitter/struct.Language.html
16//! [language func]: fn.language.html
17//! [Parser]: https://docs.rs/tree-sitter/*/tree_sitter/struct.Parser.html
18//! [tree-sitter]: https://tree-sitter.github.io/
19
20#[cfg(test)]
21mod codegen;
22
23pub extern crate tree_sitter;
24
25use tree_sitter::Language;
26
27extern "C" {
28    fn tree_sitter_wit() -> Language;
29}
30
31/// Get the tree-sitter [Language][] for this grammar.
32///
33/// [Language]: https://docs.rs/tree-sitter/*/tree_sitter/struct.Language.html
34pub fn language() -> Language {
35    unsafe { tree_sitter_wit() }
36}
37
38/// The content of the [`node-types.json`][] file for this grammar.
39///
40/// [`node-types.json`]: https://tree-sitter.github.io/tree-sitter/using-parsers#static-node-types
41pub const NODE_TYPES: &str = include_str!("../../src/node-types.json");
42
43// Uncomment these to include any queries that this grammar contains
44
45pub const HIGHLIGHTS_QUERY: &str = include_str!("../../queries/highlights.scm");
46// pub const INJECTIONS_QUERY: &str = include_str!("../../queries/injections.scm");
47// pub const LOCALS_QUERY: &str = include_str!("../../queries/locals.scm");
48// pub const TAGS_QUERY: &str = include_str!("../../queries/tags.scm");
49
50#[cfg(test)]
51mod tests {
52    use std::{
53        io::ErrorKind,
54        path::Path,
55        process::{Command, Output},
56    };
57
58    use quote::ToTokens;
59
60    use crate::{codegen, NODE_TYPES};
61
62    #[test]
63    fn test_can_load_grammar() {
64        let mut parser = tree_sitter::Parser::new();
65        parser
66            .set_language(&super::language())
67            .expect("Error loading Wit grammar");
68    }
69
70    #[test]
71    fn run_tree_sitter_tests() {
72        let parser_root = Path::new(env!("CARGO_MANIFEST_DIR"));
73
74        let mut cmd = Command::new("tree-sitter");
75        cmd.arg("test").current_dir(parser_root);
76
77        match cmd.output() {
78            Ok(Output { status, .. }) if status.success() => {}
79            Ok(Output {
80                status,
81                stdout,
82                stderr,
83            }) => {
84                let stdout = String::from_utf8_lossy(&stdout);
85                if !stdout.is_empty() {
86                    println!("==== Stdout ====");
87                    println!("{stdout}");
88                }
89                let stderr = String::from_utf8_lossy(&stderr);
90                if !stderr.is_empty() {
91                    println!("==== Stderr ====");
92                    println!("{stderr}");
93                }
94
95                panic!("`{cmd:?}` failed: {status}");
96            }
97            Err(e) if e.kind() == ErrorKind::NotFound => {
98                // The tree-sitter CLI isn't installed. Ignore.
99            }
100            Err(e) => {
101                panic!("{e}");
102            }
103        }
104    }
105
106    #[test]
107    fn generate_ast() {
108        let tokens = codegen::generate_ast(NODE_TYPES);
109        let src = format_rust(tokens);
110        let ast_rs = project_root().join("crates/wit-compiler/src/ast/generated.rs");
111        ensure_file_contents(ast_rs, src);
112    }
113
114    /// Get the root directory for this repository.
115    pub fn project_root() -> &'static Path {
116        Path::new(env!("CARGO_MANIFEST_DIR"))
117            .ancestors()
118            .find(|p| p.join(".git").exists())
119            .unwrap()
120    }
121
122    /// Format some Rust tokens.
123    ///
124    /// # Panics
125    ///
126    /// It is assumed that the tokens would parse as a Rust file.
127    pub fn format_rust(contents: impl ToTokens) -> String {
128        let contents = syn::parse2(contents.to_token_stream())
129            .expect("Unable to parse the tokens as a syn::File");
130        prettyplease::unparse(&contents)
131    }
132
133    /// Check that a particular file has the desired contents.
134    ///
135    /// If the file is missing or outdated, this function will update the file and
136    /// trigger a panic to fail any test this is called from.
137    pub fn ensure_file_contents(path: impl AsRef<Path>, contents: impl AsRef<str>) {
138        let path = path.as_ref();
139        let contents = normalize_newlines(contents.as_ref());
140
141        if let Ok(old_contents) = std::fs::read_to_string(path) {
142            if contents == normalize_newlines(&old_contents) {
143                // File is already up to date
144                return;
145            }
146        }
147
148        let display_path = path.strip_prefix(project_root()).unwrap_or(path);
149
150        eprintln!("{} was not up-to-date, updating...", display_path.display());
151
152        if std::env::var("CI").is_ok() {
153            eprintln!("Note: run `cargo test` locally and commit the updated files");
154        }
155
156        if let Some(parent) = path.parent() {
157            let _ = std::fs::create_dir_all(parent);
158        }
159        std::fs::write(path, contents).unwrap();
160        panic!("some file was not up to date and has been updated. Please re-run the tests.");
161    }
162
163    fn normalize_newlines(s: &str) -> String {
164        s.replace("\r\n", "\n")
165    }
166}
tree_sitter_wit/lib.rs

tree_sitter_wit/
lib.rs
