[dingus] Color syntax nodes red when they are errors

dingus/dingus.js

@@ -72,8 +72,6 @@ let grammar_editor = null;
 let input_editor = null;
 
 function render_parse_results(message) {
-  console.log("WHAT?");
-
   function render_tree_node(parent, node) {
     const tree_div = document.createElement("div");
     tree_div.classList.add("parsed-node");
@@ -89,8 +87,12 @@ function render_parse_results(message) {
         {scroll: true},
       );
     };
+    if (node.start == node.end) {
+      node_label.classList.add("parsed-error-node");
+    }
     tree_div.appendChild(node_label);
 
+
     if (node.kind === "tree") {
       tree_div.classList.add("parsed-tree");
       for (const child of node.children) {

dingus/style.css

@@ -57,6 +57,10 @@ body {
   margin-left: 1rem;
 }
 
+.parsed-error-node {
+  color: red;
+}
+
 .main-textarea {
   height: 100%;
   width: 100%;