diff --git a/codetab.ts b/codetab.ts
index d06c3f7..04a0456 100644
--- a/codetab.ts
+++ b/codetab.ts
@@ -301,6 +301,7 @@ const drawCodeField = (code: string, x: number, y: number, w: number, h: number)
 		fillRect(x+anchorX*fontWidth-scrollX, y+anchorY*(fontHeight+1)-scrollY, fontWidth+1, fontHeight+1, COLOR.GREEN);
 		fillRect(x+focusX*fontWidth-scrollX, y+focusY*(fontHeight+1)-scrollY, fontWidth+1, fontHeight+1, COLOR.YELLOW);
 	}
+	// TODO: syntax highlight built-in functions
 	const tokens = [...tokenize(code)];
 	let cx = 0;
 	let cy = 0;