From f2e1251009a5dd5db61c28f02696aedf33338a29 Mon Sep 17 00:00:00 2001
From: skal <pascal.massimino@gmail.com>
Date: Tue, 10 Feb 2026 00:45:38 +0100
Subject: fix: Use placeholder technique to prevent syntax highlighting overlap

Replace comments/strings with placeholders, highlight rest, restore.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
---
 tools/shader_editor/index.html | 40 ++++++++++++++++++++++++----------------
 1 file changed, 24 insertions(+), 16 deletions(-)

(limited to 'tools/shader_editor/index.html')

diff --git a/tools/shader_editor/index.html b/tools/shader_editor/index.html
index c7feffc..bad0abb 100644
--- a/tools/shader_editor/index.html
+++ b/tools/shader_editor/index.html
@@ -682,36 +682,44 @@ const syntaxHighlight = document.getElementById('syntax-highlight');
 let composeTimeout = null;
 
 function highlightWGSL(code) {
-    let highlighted = code
+    const escaped = code
         .replace(/&/g, '&amp;')
         .replace(/</g, '&lt;')
         .replace(/>/g, '&gt;');
 
-    // Tokenize to avoid overlapping matches
-    const tokens = [];
-    let lastIndex = 0;
+    // Use placeholders to prevent overlapping matches
+    const placeholders = [];
+    let result = escaped;
 
-    // Match comments, strings, then keywords/types/etc
+    // Process in priority order: comments, strings, then syntax
     const patterns = [
         { regex: /\/\/.*$/gm, className: 'hl-comment' },
         { regex: /"(?:[^"\\]|\\.)*"/g, className: 'hl-string' },
-        { regex: /@\w+/g, className: 'hl-attribute' },
-        { regex: /\b(?:fn|var|let|const|struct|if|else|for|while|return|break|continue|switch|case|default|loop|continuing)\b/g, className: 'hl-keyword' },
-        { regex: /\b(?:f32|i32|u32|bool|vec2|vec3|vec4|mat2x2|mat3x3|mat4x4|sampler|texture_2d|array)\b/g, className: 'hl-type' },
-        { regex: /\b\d+\.?\d*\b/g, className: 'hl-number' },
-        { regex: /\b[a-z_]\w*(?=\s*\()/g, className: 'hl-function' },
     ];
 
-    // Simple sequential replacement (good enough for basic highlighting)
+    // Replace comments and strings with placeholders first
     patterns.forEach(({ regex, className }) => {
-        highlighted = highlighted.replace(regex, match => {
-            // Don't re-highlight if already inside a span
-            if (/<span/.test(match)) return match;
-            return `<span class="${className}">${match}</span>`;
+        result = result.replace(regex, match => {
+            const placeholder = `__PLACEHOLDER_${placeholders.length}__`;
+            placeholders.push(`<span class="${className}">${match}</span>`);
+            return placeholder;
         });
     });
 
-    return highlighted;
+    // Now highlight syntax in remaining text
+    result = result
+        .replace(/@\w+/g, '<span class="hl-attribute">$&</span>')
+        .replace(/\b(?:fn|var|let|const|struct|if|else|for|while|return|break|continue|switch|case|default|loop|continuing)\b/g, '<span class="hl-keyword">$&</span>')
+        .replace(/\b(?:f32|i32|u32|bool|vec2|vec3|vec4|mat2x2|mat3x3|mat4x4|sampler|texture_2d|array)\b/g, '<span class="hl-type">$&</span>')
+        .replace(/\b\d+\.?\d*\b/g, '<span class="hl-number">$&</span>')
+        .replace(/\b[a-z_]\w*(?=\s*\()/g, '<span class="hl-function">$&</span>');
+
+    // Restore placeholders
+    placeholders.forEach((replacement, i) => {
+        result = result.replace(`__PLACEHOLDER_${i}__`, replacement);
+    });
+
+    return result;
 }
 
 function updateHighlight() {
-- 
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