diff --git a/Lib/octave/carrays.i b/Lib/octave/carrays.i
index 454762aa1..014de37ff 100644
--- a/Lib/octave/carrays.i
+++ b/Lib/octave/carrays.i
@@ -1,5 +1,5 @@
 %define %array_class(TYPE,NAME)
-  %array_class_wrap(TYPE,NAME,__paren,__paren_asgn)
+  %array_class_wrap(TYPE,NAME,__paren__,__paren_asgn__)
 %enddef
 
 %include <typemaps/carrays.swg>