From b9590c4a10c5df34f860988ab9847221b106ecc6 Mon Sep 17 00:00:00 2001
From: Justin Lin <caterpillar@openhome.cc>
Date: Mon, 27 Jan 2020 09:41:16 +0800
Subject: [PATCH] refactor

---
 src/_impl/_archimedean_spiral_impl.scad | 28 +++++++++++++++++++++++++
 src/archimedean_spiral.scad             | 28 ++-----------------------
 2 files changed, 30 insertions(+), 26 deletions(-)
 create mode 100644 src/_impl/_archimedean_spiral_impl.scad

diff --git a/src/_impl/_archimedean_spiral_impl.scad b/src/_impl/_archimedean_spiral_impl.scad
new file mode 100644
index 00000000..9caa9207
--- /dev/null
+++ b/src/_impl/_archimedean_spiral_impl.scad
@@ -0,0 +1,28 @@
+function _radian_step(b, theta, l) =
+    let(
+        r_square = pow(b * theta, 2),
+        double_r_square = 2 * r_square
+    )
+    acos((double_r_square - pow(l, 2)) / double_r_square) / 180 * PI;
+
+function _find_radians(b, point_distance, radians, n, count = 1) =
+    let(pre_radians = radians[count - 1])
+    count == n ? radians : (
+        _find_radians(
+            b, 
+            point_distance, 
+            concat(
+                radians,
+                [pre_radians + _radian_step(b, pre_radians, point_distance)]
+            ), 
+            n,
+        count + 1) 
+    );
+
+function _archimedean_spiral_impl(arm_distance, init_angle, point_distance, num_of_points, rt_dir) =
+    let(b = arm_distance / (2 * PI), init_radian = init_angle * PI / 180)
+    [
+        for(theta = _find_radians(b, point_distance, [init_radian], num_of_points)) 
+           let(r = b * theta, a = (rt_dir == "CT_CLK" ? 1 : -1) * theta * 57.2958)
+           [[r * cos(a), r * sin(a)], a]
+    ];
\ No newline at end of file
diff --git a/src/archimedean_spiral.scad b/src/archimedean_spiral.scad
index a638bdde..faa565ab 100644
--- a/src/archimedean_spiral.scad
+++ b/src/archimedean_spiral.scad
@@ -8,31 +8,7 @@
 *
 **/ 
 
-function _radian_step(b, theta, l) =
-    let(
-        r_square = pow(b * theta, 2),
-        double_r_square = 2 * r_square
-    )
-    acos((double_r_square - pow(l, 2)) / double_r_square) / 180 * PI;
-
-function _find_radians(b, point_distance, radians, n, count = 1) =
-    let(pre_radians = radians[count - 1])
-    count == n ? radians : (
-        _find_radians(
-            b, 
-            point_distance, 
-            concat(
-                radians,
-                [pre_radians + _radian_step(b, pre_radians, point_distance)]
-            ), 
-            n,
-        count + 1) 
-    );
+use <_impl/_archimedean_spiral_impl.scad>;
 
 function archimedean_spiral(arm_distance, init_angle, point_distance, num_of_points, rt_dir = "CT_CLK") =
-    let(b = arm_distance / (2 * PI), init_radian = init_angle * PI / 180)
-    [
-        for(theta = _find_radians(b, point_distance, [init_radian], num_of_points)) 
-           let(r = b * theta, a = (rt_dir == "CT_CLK" ? 1 : -1) * theta * 57.2958)
-           [[r * cos(a), r * sin(a)], a]
-    ];
\ No newline at end of file
+    _archimedean_spiral_impl(arm_distance, init_angle, point_distance, num_of_points, rt_dir);
\ No newline at end of file