From 386e8b934e4598cc8ae34a5ed36726c926e5cf21 Mon Sep 17 00:00:00 2001
From: Justin Lin <caterpillar@openhome.cc>
Date: Sat, 21 Sep 2019 08:25:26 +0800
Subject: [PATCH] refactor

---
 src/bspline_curve.scad | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/bspline_curve.scad b/src/bspline_curve.scad
index b34f527a..70bb381a 100644
--- a/src/bspline_curve.scad
+++ b/src/bspline_curve.scad
@@ -40,11 +40,12 @@ function _bspline_curve_nvi(v, i, l, t, degree, knots) =
 function _bspline_curve_nvl(v, l, s, t, degree, knots, i) = 
     i == (s - degree - 1 + l) ? v :
     let(
+        leng_v = len(v),
         nvi = _bspline_curve_nvi(v, i, l, t, degree, knots),
         nv = concat(
             [for(j = 0; j < i; j = j + 1) v[j]],
             nvi,
-            [for(j = i + 1; j < len(v); j = j + 1) v[j]]
+            [for(j = i + 1; j < leng_v; j = j + 1) v[j]]
         )
     )
     _bspline_curve_nvl(nv, l, s, t, degree, knots, i - 1);