feat(grammar): add "inherits" field if available

cli/src/generate/dsl.js

@@ -223,6 +223,8 @@ function RuleBuilder(ruleMap) {
 }
 
 function grammar(baseGrammar, options) {
+  let inherits = null;
+
   if (!options) {
     options = baseGrammar;
     baseGrammar = {
@@ -237,6 +239,7 @@ function grammar(baseGrammar, options) {
     };
   } else {
     baseGrammar = baseGrammar.grammar;
+    inherits = baseGrammar.name;
   }
 
   let externals = baseGrammar.externals;
@@ -279,6 +282,14 @@ function grammar(baseGrammar, options) {
     throw new Error("Grammar's 'name' property must not start with a digit and cannot contain non-word characters.");
   }
 
+  if (inherits && typeof inherits !== "string") {
+    throw new Error("Base grammar's 'name' property must be a string.");
+  }
+
+  if (inherits && !/^[a-zA-Z_]\w*$/.test(name)) {
+    throw new Error("Base grammar's 'name' property must not start with a digit and cannot contain non-word characters.");
+  }
+
   const rules = Object.assign({}, baseGrammar.rules);
   if (options.rules) {
     if (typeof options.rules !== "object") {
@@ -407,7 +418,7 @@ function grammar(baseGrammar, options) {
     throw new Error("Grammar must have at least one rule.");
   }
 
-  return { grammar: { name, word, rules, extras, conflicts, precedences, externals, inline, supertypes } };
+  return { grammar: { name, inherits, word, rules, extras, conflicts, precedences, externals, inline, supertypes } };
 }
 
 function checkArguments(args, ruleCount, caller, callerName, suffix = '', argType = 'rule') {

cli/src/generate/grammar-schema.json

@@ -14,6 +14,12 @@
       "pattern": "^[a-zA-Z_]\\w*"
     },
 
+    "inherits": {
+      "description": "the name of the parent grammar",
+      "type": "string",
+      "pattern": "^[a-zA-Z_]\\w*"
+    },
+
     "rules": {
       "type": "object",
       "patternProperties": {

cli/src/generate/mod.rs

@@ -199,7 +199,7 @@ fn load_js_grammar_file(grammar_path: &Path, js_runtime: Option<&str>) -> Result
     let mut node_stdin = node_process
         .stdin
         .take()
-        .with_context(|| "Failed to open stdin for node")?;
+        .with_context(|| format!("Failed to open stdin for {js_runtime}"))?;
     let cli_version = Version::parse(env!("CARGO_PKG_VERSION"))
         .with_context(|| "Could not parse this package's version as semver.")?;
     write!(
@@ -209,20 +209,20 @@ fn load_js_grammar_file(grammar_path: &Path, js_runtime: Option<&str>) -> Result
         global.TREE_SITTER_CLI_VERSION_PATCH = {};",
         cli_version.major, cli_version.minor, cli_version.patch,
     )
-    .with_context(|| "Failed to write tree-sitter version to node's stdin")?;
+    .with_context(|| format!("Failed to write tree-sitter version to {js_runtime}'s stdin"))?;
     let javascript_code = include_bytes!("./dsl.js");
     node_stdin
         .write(javascript_code)
-        .with_context(|| "Failed to write grammar dsl to node's stdin")?;
+        .with_context(|| format!("Failed to write grammar dsl to {js_runtime}'s stdin"))?;
     drop(node_stdin);
     let output = node_process
         .wait_with_output()
-        .with_context(|| "Failed to read output from node")?;
+        .with_context(|| format!("Failed to read output from {js_runtime}"))?;
     match output.status.code() {
-        None => panic!("Node process was killed"),
+        None => panic!("{js_runtime} process was killed"),
         Some(0) => {
-            let stdout =
-                String::from_utf8(output.stdout).with_context(|| "Got invalid UTF8 from node")?;
+            let stdout = String::from_utf8(output.stdout)
+                .with_context(|| format!("Got invalid UTF8 from {js_runtime}"))?;
 
             let mut grammar_json = &stdout[..];
 
@@ -244,7 +244,7 @@ fn load_js_grammar_file(grammar_path: &Path, js_runtime: Option<&str>) -> Result
             .with_context(|| "Failed to serialize grammar JSON")?
                 + "\n")
         }
-        Some(code) => Err(anyhow!("Node process exited with status {code}")),
+        Some(code) => Err(anyhow!("{js_runtime} process exited with status {code}")),
     }
 }