diff --git a/grammar.txt b/grammar.txt
index d806f64..3e9b661 100644
--- a/grammar.txt
+++ b/grammar.txt
@@ -70,6 +70,7 @@
             | "false"
             | "true"
             | "null"
+            | "(" <expression> ")"
 
 <object-literal> = "{}"