with doesn't create its own reference unless necessary

moonscript/transform.lua

@@ -10,6 +10,9 @@ do
   NameProxy, LocalName = _table_0.NameProxy, _table_0.LocalName
 end
 local destructure = require("moonscript.transform.destructure")
+local NOOP = {
+  "noop"
+}
 local implicitly_return
 local Run
 do
@@ -683,12 +686,19 @@ local Statement = Transformer({
     return node
   end,
   with = function(self, node, ret)
-    local _, exp, block = unpack(node)
-    local scope_name = NameProxy("with")
-    local named_assign
+    local exp, block = unpack(node, 2)
+    local copy_scope = true
+    local scope_name, named_assign
     if ntype(exp) == "assign" then
       local names, values = unpack(exp, 2)
-      local assign_name = names[1]
+      local first_name = names[1]
+      if ntype(first_name) == "value" then
+        scope_name = first_name
+        named_assign = exp
+        exp = values[1]
+        copy_scope = false
+      else
+        scope_name = NameProxy("with")
         exp = values[1]
         values[1] = scope_name
         named_assign = {
@@ -697,14 +707,17 @@ local Statement = Transformer({
           values
         }
       end
+    elseif self:is_local(exp) then
+      scope_name = exp
+      copy_scope = false
+    end
+    scope_name = scope_name or NameProxy("with")
     return build["do"]({
       Run(function(self)
         return self:set("scope_var", scope_name)
       end),
-      build.assign_one(scope_name, exp),
-      build.group({
-        named_assign
-      }),
+      copy_scope and build.assign_one(scope_name, exp) or NOOP,
+      named_assign or NOOP,
       build.group(block),
       (function()
         if ret then
@@ -1363,9 +1376,7 @@ implicitly_return = function(scope)
       return scope.transform.statement(stm, fn)
     elseif types.manual_return[t] or not types.is_value(stm) then
       if is_top and t == "return" and stm[2] == "" then
-        return {
-          "noop"
-        }
+        return NOOP
       else
         return stm
       end

moonscript/transform.moon

@@ -9,6 +9,7 @@ import insert from table
 import NameProxy, LocalName from require "moonscript.transform.names"
 
 destructure = require "moonscript.transform.destructure"
+NOOP = {"noop"}
 
 local implicitly_return
 
@@ -339,21 +340,36 @@ Statement = Transformer {
     node
 
   with: (node, ret) =>
-    _, exp, block = unpack node
+    exp, block = unpack node, 2
 
-    scope_name = NameProxy "with"
+    copy_scope = true
+    local scope_name, named_assign
 
-    named_assign = if ntype(exp) == "assign"
+    if ntype(exp) == "assign"
       names, values = unpack exp, 2
-      assign_name = names[1]
+      first_name = names[1]
+
+      if ntype(first_name) == "value"
+        scope_name = first_name
+        named_assign = exp
+        exp = values[1]
+        copy_scope = false
+      else
+        scope_name = NameProxy "with"
         exp = values[1]
         values[1] = scope_name
-      {"assign", names, values}
+        named_assign = {"assign", names, values}
+
+    elseif @is_local exp
+      scope_name = exp
+      copy_scope = false
+
+    scope_name or= NameProxy "with"
 
     build.do {
       Run => @set "scope_var", scope_name
-      build.assign_one scope_name, exp
-      build.group { named_assign }
+      copy_scope and build.assign_one(scope_name, exp) or NOOP
+      named_assign or NOOP
       build.group block
 
       if ret
@@ -747,7 +763,7 @@ implicitly_return = (scope) ->
     elseif types.manual_return[t] or not types.is_value stm
       -- remove blank return statement
       if is_top and t == "return" and stm[2] == ""
-        {"noop"}
+        NOOP
       else
         stm
     else

spec/inputs/with.moon

@@ -1,10 +1,12 @@
 
+do
   a = ->
     with something
       print .hello
       print hi
       print "world"
 
+do
   with leaf
     .world!
     .world 1,2,3
@@ -18,19 +20,22 @@ with leaf
     \hi "yeah", "man"
     .world = 200
 
+do
   zyzyzy = with something
     .set_state "hello world"
 
-
+do
   x = 5 + with Something!
     \write "hello world"
 
 
+do
   x = {
     hello: with yeah
       \okay!
   }
 
+do
   with foo
     \prop"something".hello
     .prop\send(one)
@@ -39,6 +44,7 @@ with foo
 
 --
 
+do
   with a, b -- b is lost
     print .world
 
@@ -59,6 +65,34 @@ print with a, b = 1, 2
   p = with hello!.x, world!.y = 1, 2
     print a + b
 
+--
+
+do
+  x = "hello"
+  with x
+    x\upper!
+
+do
+  with k = "jo"
+    print \upper!
+
+do
+  with a,b,c = "", "", ""
+    print \upper!
+
+do
+  a = "bunk"
+  with a,b,c = "", "", ""
+    print \upper!
+
+do
+  with j
+    print \upper!
+
+do
+  with k.j = "jo"
+    print \upper!
+
 
 
 

spec/outputs/export.lua

@@ -76,7 +76,6 @@ do
     local hallo = 3434
   end
   do
-    local _with_0 = tmp
     local j = 2000
   end
 end

spec/outputs/with.lua

@@ -1,3 +1,4 @@
+do
   local a
   a = function()
     do
@@ -8,6 +9,8 @@ a = function()
       return _with_0
     end
   end
+end
+do
   do
     local _with_0 = leaf
     _with_0.world()
@@ -18,12 +21,16 @@ do
     _with_0:hi("yeah", "man")
     _with_0.world = 200
   end
+end
+do
   local zyzyzy
   do
     local _with_0 = something
     _with_0.set_state("hello world")
     zyzyzy = _with_0
   end
+end
+do
   local x = 5 + (function()
     do
       local _with_0 = Something()
@@ -31,7 +38,9 @@ local x = 5 + (function()
       return _with_0
     end
   end)()
-x = {
+end
+do
+  local x = {
     hello = (function()
       do
         local _with_0 = yeah
@@ -40,43 +49,41 @@ x = {
       end
     end)()
   }
+end
+do
   do
     local _with_0 = foo
     local _ = _with_0:prop("something").hello
     _with_0.prop:send(one)
     _with_0.prop:send(one)
   end
+end
+do
   do
     local _with_0 = a, b
     print(_with_0.world)
   end
   local mod
   do
-  local _with_0 = { }
-  local _M = _with_0
-  _with_0.Thing = "hi"
-  mod = _with_0
+    local _M = { }
+    _M.Thing = "hi"
+    mod = _M
   end
   do
-  local _with_0 = something
-  local b
-  a, b = _with_0, pooh
-  print(_with_0.world)
+    local a, b = something, pooh
+    print(a.world)
   end
+  local x
   do
-  local _with_0 = 1
-  local b
-  a, b = _with_0, 2
+    local a, b = 1, 2
     print(a + b)
-  x = _with_0
+    x = a
   end
   print((function()
     do
-    local _with_0 = 1
-    local b
-    a, b = _with_0, 2
+      local a, b = 1, 2
       print(a + b)
-    return _with_0
+      return a
     end
   end)())
   local p
@@ -86,3 +93,44 @@ do
     print(a + b)
     p = _with_0
   end
+end
+do
+  local x = "hello"
+  do
+    x:upper()
+  end
+end
+do
+  do
+    local k = "jo"
+    print(k:upper())
+  end
+end
+do
+  do
+    local a, b, c = "", "", ""
+    print(a:upper())
+  end
+end
+do
+  local a = "bunk"
+  do
+    local b, c
+    a, b, c = "", "", ""
+    print(a:upper())
+  end
+end
+do
+  do
+    local _with_0 = j
+    print(_with_0:upper())
+  end
+end
+do
+  do
+    local _with_0 = "jo"
+    k.j = _with_0
+    print(_with_0:upper())
+    return _with_0
+  end
+end