reuse locals for unpack loops

moonscript/transform.lua

@@ -754,7 +754,7 @@ local Statement = Transformer({
     if ntype(source) == "unpack" then
       local list = source[2]
       local index_name = NameProxy("index")
-      local list_name = NameProxy("list")
+      local list_name = self:is_local(list) and list or NameProxy("list")
       local slice_var = nil
       local bounds
       if is_slice(list) then
@@ -796,8 +796,8 @@ local Statement = Transformer({
         }
       end
       return build.group({
-        build.assign_one(list_name, list),
-        slice_var,
+        list_name ~= list and build.assign_one(list_name, list) or NOOP,
+        slice_var or NOOP,
         build["for"]({
           name = index_name,
           bounds = bounds,
@@ -806,7 +806,7 @@ local Statement = Transformer({
               "assign",
               node.names,
               {
-                list_name:index(index_name)
+                NameProxy.index(list_name, index_name)
               }
             },
             build.group(node.body)

moonscript/transform.moon

@@ -396,7 +396,7 @@ Statement = Transformer {
       list = source[2]
 
       index_name = NameProxy "index"
-      list_name = NameProxy "list"
+      list_name = @is_local(list) and list or NameProxy "list"
 
       slice_var = nil
       bounds = if is_slice list
@@ -418,13 +418,13 @@ Statement = Transformer {
         {1, {"length", list_name}}
 
       return build.group {
-        build.assign_one list_name, list
-        slice_var
+        list_name != list and build.assign_one(list_name, list) or NOOP
+        slice_var or NOOP
         build["for"] {
           name: index_name
           bounds: bounds
           body: {
-            {"assign", node.names, {list_name\index index_name}}
+            {"assign", node.names, { NameProxy.index list_name, index_name }}
             build.group node.body
           }
         }

spec/inputs/loops.moon

@@ -114,3 +114,11 @@ for x=1,10
   for y = 2,12
     continue if y % 3 == 0
 
+--
+
+do
+  xxx = {1,2,3,4}
+  for thing in *xxx
+    print thing
+
+

spec/outputs/destructure.lua

@@ -101,9 +101,8 @@ do
       4
     }
   }
-  local _list_0 = thing
-  for _index_0 = 1, #_list_0 do
-    local _des_0 = _list_0[_index_0]
+  for _index_0 = 1, #thing do
+    local _des_0 = thing[_index_0]
     local x, y
     x, y = _des_0[1], _des_0[2]
     print(x, y)

spec/outputs/lists.lua

@@ -164,25 +164,22 @@ end
 local double = (function()
   local _accum_0 = { }
   local _len_0 = 1
-  local _list_0 = items
-  for _index_0 = 1, #_list_0 do
-    x = _list_0[_index_0]
+  for _index_0 = 1, #items do
+    x = items[_index_0]
     _accum_0[_len_0] = x * 2
     _len_0 = _len_0 + 1
   end
   return _accum_0
 end)()
-local _list_0 = double
-for _index_0 = 1, #_list_0 do
-  x = _list_0[_index_0]
+for _index_0 = 1, #double do
+  x = double[_index_0]
   print(x)
 end
 local cut = (function()
   local _accum_0 = { }
   local _len_0 = 1
-  local _list_1 = items
-  for _index_0 = 1, #_list_1 do
-    x = _list_1[_index_0]
+  for _index_0 = 1, #items do
+    x = items[_index_0]
     if x > 3 then
       _accum_0[_len_0] = x
       _len_0 = _len_0 + 1
@@ -193,21 +190,18 @@ end)()
 local hello = (function()
   local _accum_0 = { }
   local _len_0 = 1
-  local _list_1 = items
-  for _index_0 = 1, #_list_1 do
-    x = _list_1[_index_0]
-    local _list_2 = items
-    for _index_1 = 1, #_list_2 do
-      local y = _list_2[_index_1]
+  for _index_0 = 1, #items do
+    x = items[_index_0]
+    for _index_1 = 1, #items do
+      local y = items[_index_1]
       _accum_0[_len_0] = x + y
       _len_0 = _len_0 + 1
     end
   end
   return _accum_0
 end)()
-local _list_1 = hello
-for _index_0 = 1, #_list_1 do
-  local z = _list_1[_index_0]
+for _index_0 = 1, #hello do
+  local z = hello[_index_0]
   print(z)
 end
 x = {
@@ -219,38 +213,38 @@ x = {
   6,
   7
 }
-local _list_2 = x
+local _list_0 = x
 local _max_0 = -5
-for _index_0 = 2, _max_0 < 0 and #_list_2 + _max_0 or _max_0, 2 do
+for _index_0 = 2, _max_0 < 0 and #_list_0 + _max_0 or _max_0, 2 do
+  local y = _list_0[_index_0]
+  print(y)
+end
+local _list_1 = x
+local _max_1 = 3
+for _index_0 = 1, _max_1 < 0 and #_list_1 + _max_1 or _max_1 do
+  local y = _list_1[_index_0]
+  print(y)
+end
+local _list_2 = x
+for _index_0 = 2, #_list_2 do
   local y = _list_2[_index_0]
   print(y)
 end
 local _list_3 = x
-local _max_1 = 3
-for _index_0 = 1, _max_1 < 0 and #_list_3 + _max_1 or _max_1 do
+for _index_0 = 1, #_list_3, 2 do
   local y = _list_3[_index_0]
   print(y)
 end
 local _list_4 = x
-for _index_0 = 2, #_list_4 do
+for _index_0 = 2, #_list_4, 2 do
   local y = _list_4[_index_0]
   print(y)
 end
-local _list_5 = x
-for _index_0 = 1, #_list_5, 2 do
-  local y = _list_5[_index_0]
-  print(y)
-end
-local _list_6 = x
-for _index_0 = 2, #_list_6, 2 do
-  local y = _list_6[_index_0]
-  print(y)
-end
 local a, b, c = 1, 5, 2
-local _list_7 = x
+local _list_5 = x
 local _max_2 = b
-for _index_0 = a, _max_2 < 0 and #_list_7 + _max_2 or _max_2, c do
-  local y = _list_7[_index_0]
+for _index_0 = a, _max_2 < 0 and #_list_5 + _max_2 or _max_2, c do
+  local y = _list_5[_index_0]
   print(y)
 end
 local normal
@@ -266,23 +260,21 @@ normal = function(hello)
   end)()
 end
 local test = x(1, 2, 3, 4, 5)
-local _list_8 = test
-for _index_0 = 1, #_list_8 do
-  local thing = _list_8[_index_0]
+for _index_0 = 1, #test do
+  local thing = test[_index_0]
   print(thing)
 end
 local _
 _ = function()
-  local _list_9 = rows
-  for _index_0 = 1, #_list_9 do
-    local row = _list_9[_index_0]
+  local _list_6 = rows
+  for _index_0 = 1, #_list_6 do
+    local row = _list_6[_index_0]
     a = b
   end
 end
 _ = function()
-  local _list_9 = things
-  for _index_0 = 1, #_list_9 do
-    x = _list_9[_index_0]
+  for _index_0 = 1, #things do
+    x = things[_index_0]
     _ = x
   end
 end
@@ -290,9 +282,8 @@ return function()
   return (function()
     local _accum_0 = { }
     local _len_0 = 1
-    local _list_9 = things
-    for _index_0 = 1, #_list_9 do
-      x = _list_9[_index_0]
+    for _index_0 = 1, #things do
+      x = things[_index_0]
       _accum_0[_len_0] = x
       _len_0 = _len_0 + 1
     end

spec/outputs/loops.lua

@@ -51,9 +51,8 @@ local hello = {
 x = (function()
   local _accum_0 = { }
   local _len_0 = 1
-  local _list_1 = hello
-  for _index_0 = 1, #_list_1 do
-    local y = _list_1[_index_0]
+  for _index_0 = 1, #hello do
+    local y = hello[_index_0]
     if y % 2 == 0 then
       _accum_0[_len_0] = y
     end
@@ -62,9 +61,8 @@ x = (function()
   return _accum_0
 end)()
 x = function()
-  local _list_1 = hello
-  for _index_0 = 1, #_list_1 do
-    x = _list_1[_index_0]
+  for _index_0 = 1, #hello do
+    x = hello[_index_0]
     local _ = y
   end
 end
@@ -258,4 +256,16 @@ for x = 1, 10 do
   if not _continue_0 then
     break
   end
+end
+do
+  local xxx = {
+    1,
+    2,
+    3,
+    4
+  }
+  for _index_0 = 1, #xxx do
+    local thing = xxx[_index_0]
+    print(thing)
+  end
 end