From 169599f86cc0b1983c8af89e4a72fb71aa93a974 Mon Sep 17 00:00:00 2001
From: Paul Liverman III <paul.liverman.iii@gmail.com>
Date: Mon, 14 Aug 2017 06:02:36 -0700
Subject: [PATCH] added Lua-based MoonScript-compatible class system #28

---
 class.lua           | 21 +++++++++++++++++++--
 class.moon          | 39 +++++++++++++++++++--------------------
 config.ld           |  6 ++++++
 tmp.class.usage.lua | 18 +++++++++++++++---
 4 files changed, 59 insertions(+), 25 deletions(-)

diff --git a/class.lua b/class.lua
index c36a22e..db7f617 100644
--- a/class.lua
+++ b/class.lua
@@ -1,5 +1,5 @@
 local Class
-Class = function(name)
+Class = function(name, parent)
   local newClass, base
   base = {
     __index = base,
@@ -16,6 +16,23 @@ Class = function(name)
       return self
     end
   })
-  return newClass
+  if parent then
+    setmetable(base, {
+      __parent = parent.__base
+    })
+    newClass.__parent = parent
+    newClass.__index = function(cls, name)
+      local val = rawget(base, name)
+      if val == nil then
+        return parent[name]
+      else
+        return val
+      end
+    end
+    if parent.__inherited then
+      parent:__inherited(newClass)
+    end
+  end
+  return newClass, base
 end
 return Class
diff --git a/class.moon b/class.moon
index 741d69e..1c38a6a 100644
--- a/class.moon
+++ b/class.moon
@@ -1,7 +1,5 @@
--- basically, gonna use the knowledge of how MoonScript classes work to make
---  something that does the same thing using syntax similar to MiddleClass
-
-Class = (name) ->
+--- @todo document this!
+Class = (name, parent) ->
   local newClass, base
   base = {
     __index: base
@@ -19,21 +17,22 @@ Class = (name) ->
       return @
   }
 
-  return newClass
+  if parent
+    setmetable base, {
+      __parent: parent.__base
+    }
+
+    newClass.__parent = parent
+    newClass.__index = (cls, name) ->
+      val = rawget(base, name)
+      if val == nil
+        return parent[name]
+      else
+        return val
+
+    if parent.__inherited
+      parent\__inherited newClass
+
+  return newClass, base
 
 return Class
-
--- base obj with an __index to itself, contains functions accepting a self argument,
---  and __class pointing to class obj
---
--- class is obj w __init function, __base linking to base obj, and __name specifying name of class
---  it has metatable, __index is the base table (makes perfect sense),
---   __call is a function that creates a self obj w the base obj as a metatable, then calls __init
---      on it, and returns the self (__init is never meant to get directly called)
---
--- inheritance addtionally does:
---
--- new base obj will have a metatable set to parent.__base (where parent is parent class obj)
--- new class obj will have __parent value linking to parent class obj, and __index metamethod
---   that returns rawget(new base, name) or return parent class[name] if that was nil
--- if parent class had __inherited, then is called w parent class and new class
diff --git a/config.ld b/config.ld
index 97489bd..e580bf0 100644
--- a/config.ld
+++ b/config.ld
@@ -1,10 +1,16 @@
 file = {
     "init.moon",
     "elements/box.moon",
+    "elements/button.moon",
+    "elements/dynamicGrid.moon",
     "elements/element.moon",
+    "elements/grid.moon",
+    "elements/scrollbox.moon",
     "elements/text.moon",
     "elements/window.moon",
     "extensions/streamlined_get_set.moon",
+    "extensions/utility.moon",
+    "class.moon",
     "main.moon",
     "util.moon",
     "Element.luadoc",
diff --git a/tmp.class.usage.lua b/tmp.class.usage.lua
index 6431fab..0d3c68f 100644
--- a/tmp.class.usage.lua
+++ b/tmp.class.usage.lua
@@ -1,12 +1,24 @@
-local class = require "Class"
+local class = require "class"
 
-local Car = class("Car")
+local Car, CarBase = class("Car")
 
 function Car:__init(x, y)
   self.x = x or 0
   self.y = y or 0
 end
 
-function Car:print() -- this will be broken
+function CarBase:print() -- this will be correct
   print("I'm a car, at ("..self.x..","..self.y..")")
 end
+
+local Motorcycle, MotorcycleBase = class("Motorcycle", Car)
+
+function Motorcycle:__init(x, y)
+  Car.__init(self, x, y) -- if you want to use a parent's constructor, you must manually call it
+
+  -- do additional stuff or whatever
+end
+
+function MotorcycleBase:someFunc()
+  -- do whatever to an instance
+end