From 2f796164e320928376253997dccbaf66fb86639b Mon Sep 17 00:00:00 2001
From: Justin Lin <caterpillar@openhome.cc>
Date: Mon, 13 Apr 2020 08:51:30 +0800
Subject: [PATCH] refactor

---
 src/experimental/_impl/_lsystem2_impl.scad | 49 ++++++++++------------
 src/experimental/lsystem2.scad             | 13 +++---
 2 files changed, 26 insertions(+), 36 deletions(-)

diff --git a/src/experimental/_impl/_lsystem2_impl.scad b/src/experimental/_impl/_lsystem2_impl.scad
index 903c4473..9609a981 100644
--- a/src/experimental/_impl/_lsystem2_impl.scad
+++ b/src/experimental/_impl/_lsystem2_impl.scad
@@ -1,6 +1,6 @@
 use <experimental/assoc_lookup.scad>;
 use <turtle/turtle2d.scad>;
-
+ 
 // It doesn't use recursion to avoid recursion error. 
 function _join(strs) = 
     let(leng = len(strs))
@@ -18,48 +18,41 @@ function _derive(base, rule, n, i = 0) =
 function derive(rule, n) =
     _derive(assoc_lookup(rule, "S"), rule, n);
 
-function cmd(symbol, args) =
-    symbol == "F" ? ["forward", args[0]] :
-    symbol == "M" ? ["move", args[0]] :
-    symbol == "+" ? ["turn", args[1]] :
-    symbol == "-" ? ["turn", -args[1]] : 
-    symbol == "[" ? ["push"] :
-    symbol == "]" ? ["pop"] : [];
-    
-function _fd_if_mv(cmd) = 
-    cmd == "move" ? "forward" : cmd;
-
-function _next_stack(t, cmd, stack) = 
-    cmd[0] == "push" ? concat([t], stack) :
+function _next_stack(t, code, stack) = 
+    code == "[" ? concat([t], stack) :
     let(leng = len(stack))
-    cmd[0] == "pop" ? 
+    code == "]" ? 
             (leng > 1 ? [for(i = [1:leng - 1]) stack[i]] : []) :
             stack;
 
-function _next_t1(t1, t2, cmd, stack) = 
-    cmd[0] == "push" ? t1 : 
-    cmd[0] == "pop" ? stack[0] : t2; 
+function _next_t1(t1, t2, code, stack) = 
+    code == "[" ? t1 : 
+    code == "]" ? stack[0] : t2; 
     
-function _next_t2(t, cmd) = 
-    is_undef(cmd) || cmd[0] == "push" || cmd[0] == "pop" ? t : turtle2d(_fd_if_mv(cmd[0]), t, cmd[1]);
+function _next_t2(t, code, angle, leng) = 
+    is_undef(code) || code == "[" || code == "]" ? t :
+    code == "F" ? turtle2d("forward", t, leng) :
+    code == "M" ? turtle2d("forward", t, leng) :
+    code == "+" ? turtle2d("turn", t, angle) :
+    code == "-" ? turtle2d("turn", t, -angle) : t;    
 
 // It doesn't use recursion to avoid recursion error.    
-function _lines(t, cmds) = 
-    let(leng = len(cmds))
+function _lines(t, codes, angle, leng) = 
+    let(codes_leng = len(codes))
     [
         for(
             i = 0,
             stack = [],            
             t1 = t, 
-            t2 = _next_t2(t1, cmds[i]);
+            t2 = _next_t2(t1, codes[i], angle, leng);
             
-            i < leng; 
+            i < codes_leng; 
             
-            t1 = _next_t1(t1, t2, cmds[i], stack), 
-            stack = _next_stack(t1, cmds[i], stack),
+            t1 = _next_t1(t1, t2, codes[i], stack), 
+            stack = _next_stack(t1, codes[i], stack),
             i = i + 1, 
-            t2 = _next_t2(t1, cmds[i])
+            t2 = _next_t2(t1, codes[i], angle, leng)
         )
-        if(cmds[i][0] != "move" && cmds[i][0] != "push" && cmds[i][0] != "pop")
+        if(search(codes[i], "F+-") != [])
             [turtle2d("pt", t1), turtle2d("pt", t2)]
     ];
\ No newline at end of file
diff --git a/src/experimental/lsystem2.scad b/src/experimental/lsystem2.scad
index 17946e8b..b00ad56d 100644
--- a/src/experimental/lsystem2.scad
+++ b/src/experimental/lsystem2.scad
@@ -4,18 +4,15 @@ use <turtle/turtle2d.scad>;
 function lsystem2(rule, n, angle, leng = 1, heading = 0, start = [0, 0], forward_chars = "F") =
     let(
         derived = derive(rule, n),
-        replaced = _join([
+        codes = _join([
             for(c = derived)
             let(idx = search(c, forward_chars))
             idx == [] ? c : "F"
-        ]),
-        cmds = [
-            for(s = replaced) 
-            let(c = cmd(s, [leng, angle]))
-            if(c != []) c
-        ]
+        ])
     )
     _lines(
         turtle2d("create", start[0], start[0], heading), 
-        cmds
+        codes,
+        angle,
+        leng
     );
\ No newline at end of file