@@ syntax for class variables within instances

Makefile

@@ -7,3 +7,6 @@ global:
 
 compile:
 	bin/moonc moon/ moonscript/
+
+watch:
+	moonc -w moon/ moonscript/

docs/reference.md

@@ -774,6 +774,29 @@ object to retrieve class methods and properties.
     print BackPack.size -- prints 10
     ```
 
+Where as `@` can be put in front of a name to access it within self, `@@` can
+be used to access a value that is stored in the `__class` of `self`. Thus,
+`@@hello` is shorthand for `self.__class.hello`.
+
+    ```moon
+    class Counter
+      count: 0
+      new: =>
+        @@count += 1
+
+    Counter!
+    Counter!
+
+    print Counter.count -- prints 2
+    ```
+
+The calling semantics of `@@` are similar to `@`. Calling a `@@` name will pass
+the class in as the first argument using Lua's colon syntax.
+
+    ```moon
+    @@hello 1,2,3,4
+    ```
+
 ## Export Statement
 
 Because, by default, all assignments to variables that are not lexically visible will

moonscript/compile/value.lua

@@ -118,8 +118,9 @@ value_compile = {
         return error("Unknown chain action: " .. t)
       end
     end
-    if ntype(callee) == "self" and node[3] and ntype(node[3]) == "call" then
+    local t = ntype(callee)
-      callee[1] = "self_colon"
+    if (t == "self" or t == "self_class") and node[3] and ntype(node[3]) == "call" then
+      callee[1] = t .. "_colon"
     end
     local callee_value = self:value(callee)
     if ntype(callee) == "exp" then
@@ -151,7 +152,7 @@ value_compile = {
         if type(name) == "string" then
           name = name
         else
-          if name[1] == "self" then
+          if name[1] == "self" or name[1] == "self_class" then
             insert(self_args, name)
           end
           name = name[2]
@@ -305,9 +306,15 @@ value_compile = {
   self = function(self, node)
     return "self." .. self:value(node[2])
   end,
+  self_class = function(self, node)
+    return "self.__class." .. self:value(node[2])
+  end,
   self_colon = function(self, node)
     return "self:" .. self:value(node[2])
   end,
+  self_class_colon = function(self, node)
+    return "self.__class:" .. self:value(node[2])
+  end,
   raw_value = function(self, value)
     local sup = self:get("super")
     if value == "super" and sup then

moonscript/compile/value.moon

@@ -74,8 +74,9 @@ value_compile =
       else
         error "Unknown chain action: "..t
 
-    if ntype(callee) == "self" and node[3] and ntype(node[3]) == "call"
+    t = ntype(callee)
-      callee[1] = "self_colon"
+    if (t == "self" or t == "self_class") and node[3] and ntype(node[3]) == "call"
+      callee[1] = t.."_colon"
 
     callee_value = @value callee
     callee_value = @line "(", callee_value, ")" if ntype(callee) == "exp"
@@ -95,7 +96,7 @@ value_compile =
       name = if type(name) == "string"
         name
       else
-        if name[1] == "self"
+        if name[1] == "self" or name[1] == "self_class"
           insert self_args, name
         name[2]
       insert default_args, arg if default_value
@@ -176,9 +177,15 @@ value_compile =
   self: (node) =>
     "self."..@value node[2]
 
+  self_class: (node) =>
+    "self.__class."..@value node[2]
+
   self_colon: (node) =>
     "self:"..@value node[2]
 
+  self_class_colon: (node) =>
+    "self.__class:"..@value node[2]
+
   -- catch all pure string values
   raw_value: (value) =>
     sup = @get"super"

moonscript/parse.lua

@@ -268,7 +268,9 @@ local build_grammar = wrap_env(function()
 		return true
 	end) / trim
 
-	local Name = sym"@" * Name / mark"self" + Name + Space * "..." / trim
+	local SelfName = Space * "@" * ("@" * _Name / mark"self_class" + _Name / mark"self")
+
+	local Name = SelfName + Name + Space * "..." / trim
 
 	local g = lpeg.P{
 		File,

tests/inputs/class.moon

@@ -80,4 +80,14 @@ class CoolSuper
     nil
 
 
+-- selfing
+x = @hello
+x = @@hello
+
+@hello "world"
+@@hello "world"
+
+@@one @@two(4,5) @three, @four
+
+xx = (@hello, @@world, cool) ->