From b20cfd7b0d8d00dc111cfcddab96dc0fa79dd6e9 Mon Sep 17 00:00:00 2001
From: Justin Lin <justin.sdk@gmail.com>
Date: Sat, 27 Feb 2021 20:04:47 +0800
Subject: [PATCH] add shuffle

---
 src/util/shuffle.scad | 11 +++++++++++
 1 file changed, 11 insertions(+)
 create mode 100644 src/util/shuffle.scad

diff --git a/src/util/shuffle.scad b/src/util/shuffle.scad
new file mode 100644
index 00000000..7361b9e6
--- /dev/null
+++ b/src/util/shuffle.scad
@@ -0,0 +1,11 @@
+use <swap.scad>;
+
+function shuffle(lt, seed) = 
+    let(
+        leng = len(lt),
+        indices = [for(i = is_undef(seed) ? rands(0, leng, leng) : rands(0, leng, leng, seed)) floor(i)]
+    )
+    _shuffle(lt, indices, leng);
+
+function _shuffle(lt, indices, leng, i = 0) =
+    i == leng ? lt : _shuffle(swap(lt, i, indices[i]), indices, leng, i + 1);
\ No newline at end of file