diff --git a/src/backends/gr.jl b/src/backends/gr.jl
index ba5f3574..42dcffc3 100644
--- a/src/backends/gr.jl
+++ b/src/backends/gr.jl
@@ -141,12 +141,12 @@ function gr_set_fillstyle(s::Symbol)
     GR.setfillintstyle(GR.INTSTYLE_HATCH)
     GR.setfillstyle(get(
         (
-            / = 9,
-            \ = 10,
-            | = 7,
-            - = 8,
-            + = 11,
-            x = 6,
+            (/) = 9,
+            (\) = 10,
+            (|) = 7,
+            (-) = 8,
+            (+) = 11,
+            (x) = 6,
         ),
         s,
         9),