[dingus] Trying to get a web dingus working with pyodide

dingus/dingus.js

@@ -0,0 +1,60 @@
+let pending_grammar = null;
+let next_grammar = null;
+
+function submit_grammar(code) {
+  if (pending_grammar) {
+    console.log("Grammar still pending, parking it");
+    next_grammar = code;
+  } else {
+    pending_grammar = code;
+    worker.postMessage({kind: "grammar_module", data: code});
+    console.log("Grammar posted");
+  }
+}
+
+const worker = new Worker('worker.js');
+worker.onmessage = (e) => {
+  const message = e.data;
+  if (message.kind === "grammar_status") {
+    if ((message.status === "ok") || (message.status === "error")) {
+      pending_grammar = null;
+      if (next_grammar) {
+        pending_grammar = next_grammar;
+        next_grammar = null;
+
+        worker.postMessage({kind: "grammar_module", data: pending_grammar});
+        console.log("Posted another grammar");
+      }
+    }
+  }
+};
+
+
+function setup_editors() {
+  const grammar_editor = CodeMirror.fromTextArea(
+    document.getElementById("grammar"),
+    {
+      lineNumbers: true,
+      mode: "python",
+      value: "from parser import Grammar\n\nclass MyGrammar(Grammar):\n    pass\n",
+    },
+  );
+
+  let change_timer_id = null;
+  grammar_editor.doc.on("change", () => {
+    clearTimeout(change_timer_id);
+    change_timer_id = setTimeout(() => {
+      change_timer_id = null;
+      submit_grammar(grammar_editor.doc.getValue());
+    }, 100);
+  });
+
+  const input_editor = CodeMirror.fromTextArea(
+    document.getElementById("input"),
+    {
+      lineNumbers: true,
+    },
+  );
+}
+
+setup_editors();