diff --git a/src/com/annimon/everlastingsummer/Parser.java b/src/com/annimon/everlastingsummer/Parser.java
index f5fd54f..f64dd6b 100644
--- a/src/com/annimon/everlastingsummer/Parser.java
+++ b/src/com/annimon/everlastingsummer/Parser.java
@@ -535,6 +535,11 @@ public final class Parser {
         if (match(current, TokenType.WORD)) {
             return new VariableExpression(current.getText());
         }
+        if (match(current, TokenType.LPAREN)) {
+            Expression expr = expression();
+            match(TokenType.RPAREN);
+            return expr;
+        }
         throw new RuntimeException();
     }