From e544a468a231b1111c4c1805dc176d30b76fc68a Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sat, 27 Jan 2018 02:44:37 +0000
Subject: [PATCH] fairphone-case: prop: make lots of variables special (nfc)

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---
 fairphone-case.scad | 60 ++++++++++++++++++++++-----------------------
 1 file changed, 30 insertions(+), 30 deletions(-)

diff --git a/fairphone-case.scad b/fairphone-case.scad
index 7bd4f3f..f680de8 100644
--- a/fairphone-case.scad
+++ b/fairphone-case.scad
@@ -277,8 +277,8 @@ prlp10 = lpp10 + [1,1] * prl_r10o
 
 // prop
 
-prpp10 = [0,0];
-prpp11 = [0, prop_taper_len];
+$prpp10 = [0,0];
+$prpp11 = [0, prop_taper_len];
 
 prp_r10 = prl_r10;
 
@@ -630,13 +630,13 @@ module PropProfile(gamma, cut=0, rot=0){ ////toplevel
   p = phone_height - prlp10[0] - hppB[0];
   b = p + x;
 
-  q = phone_height - hppT[0]; // prpp7[0] is 0 by definition
+  q = phone_height - hppT[0]; // $prpp7[0] is 0 by definition
   a = q + x;
   c = sqrt(a*a + b*b - 2*a*b*cos(gamma));
-  alpha = acos( (b*b + c*c - a*a) / (2*b*c) );
+  $prp_alpha = acos( (b*b + c*c - a*a) / (2*b*c) );
 
-  theta = 90 - alpha;
-  beta = 180 - alpha - gamma;
+  $prp_theta = 90 - $prp_alpha;
+  beta = 180 - $prp_alpha - gamma;
   psi = 90 - beta;
 
   //echo("abc", a,b,c);
@@ -644,58 +644,58 @@ module PropProfile(gamma, cut=0, rot=0){ ////toplevel
   v1 = [ [ cos(psi), -sin(psi) ],    // x
 	 [ sin(psi),  cos(psi) ] ];  // y
 
-  prpp7 = [0, c + (lpp13[1] - prpp10[1]) ];
+  $prpp7 = [0, c + (lpp13[1] - $prpp10[1]) ];
 
   prp_r1 = prc_r1;
   prp_r11 = prop_main_th/2;
 
-  prpp1 = prpp7 + [1,0] *
+  $prpp1 = $prpp7 + [1,0] *
     // this is approximate, but will do
     (prop_main_th/2 + prop_prop_gap + prcp1[0] - epp4[0]);
-  prpp3 = prpp1 +
+  $prpp3 = $prpp1 +
     v1[0] * -prp_r1 +
     v1[1] * ((prcp2[1] - prcp1[1]) - prop_prop_gap);
-  prpp12 = prpp3 + v1[0] *
-    (prop_end_dia + prop_caserecess_taper * (prpp1[1] - prpp3[1]));
+  $prpp12 = $prpp3 + v1[0] *
+    (prop_end_dia + prop_caserecess_taper * ($prpp1[1] - $prpp3[1]));
   prp_r8 = prop_main_th;
-  prpp4 = [ prop_main_th/2, prpp3[1] ];
+  $prpp4 = [ prop_main_th/2, $prpp3[1] ];
   prp_r5 = prp_r8;
-  prpp5 = [ prpp12[0] - prp_r5,
-	    prpp3[1] - prop_prong_h + prp_r5 ];
-  prpp6 = prpp4 + [0,-1] * (prop_prong_h +
-         prop_prong_heel_slope * (prpp5[0] - prpp4[0]));
-  prpp8 = prpp4 + [0,-1] * prp_r8;
-  prpp9 = prpp8 + [-1,0] * prp_r8;
+  $prpp5 = [ $prpp12[0] - prp_r5,
+	    $prpp3[1] - prop_prong_h + prp_r5 ];
+  $prpp6 = $prpp4 + [0,-1] * (prop_prong_h +
+         prop_prong_heel_slope * ($prpp5[0] - $prpp4[0]));
+  $prpp8 = $prpp4 + [0,-1] * prp_r8;
+  $prpp9 = $prpp8 + [-1,0] * prp_r8;
 
-  //#circleat(prpp3,1);
-  //#circleat(prpp12,1);
+  //#circleat($prpp3,1);
+  //#circleat($prpp12,1);
 
   if (!cut) {
     hull(){
-      translate(prpp8)
+      translate($prpp8)
 	intersection(){
 	  circle(prp_r8);
 	  polygon([[-20,-0], [0,0], [20,20]]);
         }
-      rectfromto(prpp6, prpp9);
-      translate(prpp5) intersection(){
+      rectfromto($prpp6, $prpp9);
+      translate($prpp5) intersection(){
 	circle(prp_r5);
 	polygon([[-10,-10], [0,0], [10,0]]);
       }
-      rectfromto(prpp12 + [0,-0.1], prpp3);
+      rectfromto($prpp12 + [0,-0.1], $prpp3);
     }
     hull(){
-      circleat(prpp1, prp_r1);
-      rectfromto(prpp12 + [0,-0.1], prpp3);
+      circleat($prpp1, prp_r1);
+      rectfromto($prpp12 + [0,-0.1], $prpp3);
     }
   }
   // main shaft
-  rotate([0,0, rot*-theta]){
+  rotate([0,0, rot*-$prp_theta]){
     hull(){
       extra = cut ? prop_recess_slop : 0;
-      rectfromto(prpp6, prpp9);
-      circleat(prpp11, prp_r11 + extra);
-      circleat(prpp10, prp_r10 + extra);
+      rectfromto($prpp6, $prpp9);
+      circleat($prpp11, prp_r11 + extra);
+      circleat($prpp10, prp_r10 + extra);
     }
   }
 }
-- 
2.30.2