feat(cli): add option to select JS runtime other than node

resolves tree-sitter#465
resolves tree-sitter#1686

Author: jakesarjeant

cli/src/generate/mod.rs

@@ -44,6 +44,7 @@ pub fn generate_parser_in_directory(
     abi_version: usize,
     generate_bindings: bool,
     report_symbol_name: Option<&str>,
+    runtime: Option<&str>,
 ) -> Result<()> {
     let src_path = repo_path.join("src");
     let header_path = src_path.join("tree_sitter");
@@ -56,11 +57,11 @@ pub fn generate_parser_in_directory(
     let grammar_json;
     match grammar_path {
         Some(path) => {
-            grammar_json = load_grammar_file(path.as_ref())?;
+            grammar_json = load_grammar_file(path.as_ref(), runtime)?;
         }
         None => {
             let grammar_js_path = grammar_path.map_or(repo_path.join("grammar.js"), |s| s.into());
-            grammar_json = load_grammar_file(&grammar_js_path)?;
+            grammar_json = load_grammar_file(&grammar_js_path, runtime)?;
             fs::write(&src_path.join("grammar.json"), &grammar_json)?;
         }
     }
@@ -155,9 +156,9 @@ fn generate_parser_for_grammar_with_opts(
     })
 }
 
-pub fn load_grammar_file(grammar_path: &Path) -> Result<String> {
+pub fn load_grammar_file(grammar_path: &Path, runtime: Option<&str>) -> Result<String> {
     match grammar_path.extension().and_then(|e| e.to_str()) {
-        Some("js") => Ok(load_js_grammar_file(grammar_path)?),
+        Some("js") => Ok(load_js_grammar_file(grammar_path, runtime)?),
         Some("json") => Ok(fs::read_to_string(grammar_path)?),
         _ => Err(anyhow!(
             "Unknown grammar file extension: {:?}",
@@ -166,14 +167,15 @@ pub fn load_grammar_file(grammar_path: &Path) -> Result<String> {
     }
 }
 
-fn load_js_grammar_file(grammar_path: &Path) -> Result<String> {
+fn load_js_grammar_file(grammar_path: &Path, runtime: Option<&str>) -> Result<String> {
     let grammar_path = fs::canonicalize(grammar_path)?;
-    let mut node_process = Command::new("node")
+    let js_runtime = runtime.or(Some("node")).unwrap();
+    let mut node_process = Command::new(js_runtime)
         .env("TREE_SITTER_GRAMMAR_PATH", grammar_path)
         .stdin(Stdio::piped())
         .stdout(Stdio::piped())
         .spawn()
-        .expect("Failed to run `node`");
+        .expect(format!("Failed to run `{js_runtime}`").as_str());
 
     let mut node_stdin = node_process
         .stdin

cli/src/main.rs

@@ -126,6 +126,14 @@ fn run() -> Result<()> {
                         .long("report-states-for-rule")
                         .value_name("rule-name")
                         .takes_value(true),
+                )
+                .arg(
+                    Arg::with_name("js-runtime")
+                        .long("js-runtime")
+                        .short("R")
+                        .takes_value(true)
+                        .value_name("binary")
+                        .help("Use a JavaScript runtime other than node"),
                 ),
         )
         .subcommand(
@@ -327,13 +335,15 @@ fn run() -> Result<()> {
                             version.parse().expect("invalid abi version flag")
                         }
                     });
+            let runtime = matches.value_of("js-runtime");
             let generate_bindings = !matches.is_present("no-bindings");
             generate::generate_parser_in_directory(
                 &current_dir,
                 grammar_path,
                 abi_version,
                 generate_bindings,
                 report_symbol_name,
+                runtime
             )?;
             if build {
                 if let Some(path) = libdir {