From 4f4be3d1d02f9740e4df3896fc2c85bbac4df62f Mon Sep 17 00:00:00 2001
From: Adrian Mariano <avm4@cornell.edu>
Date: Wed, 29 Jul 2020 06:27:19 -0400
Subject: [PATCH] tweak to _list_pattern

---
 common.scad | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/common.scad b/common.scad
index 3f66095..b26617b 100644
--- a/common.scad
+++ b/common.scad
@@ -115,8 +115,8 @@ function is_list_of(list,pattern) =
     []==[for(entry=list) if (entry*0 != pattern) entry];
 
 function _list_pattern(list) =
-  [for(entry=list) is_list(entry) ? _list_pattern(entry) : 0];
-
+  is_list(list) ? [for(entry=list) is_list(entry) ? _list_pattern(entry) : 0]
+                : 0;