lua如何构造类

 function class(super, autoConstructSuper)
     local classType = {};
     classType.autoConstructSuper = autoConstructSuper or (autoConstructSuper == nil);

     if super then
         classType.super = super;
         local mt = getmetatable(super);
         setmetatable(classType, { __index = super; __newindex = mt and mt.__newindex;});
     else
         classType.setDelegate = function(self,delegate)
             self.m_delegate = delegate;
         end
     end

     return classType;
 end

 function new(classType, ...)
     local obj = {};
     local mt = getmetatable(classType);
     setmetatable(obj, { __index = classType; __newindex = mt and mt.__newindex;});
     do
         local create;
         create =
             function(c, ...)
                 if c.super and c.autoConstructSuper then
                     create(c.super, ...);
                 end
                 if rawget(c,"ctor") then
                     obj.currentSuper = c.super;
                     c.ctor(obj, ...);
                 end
             end

         create(classType, ...);
     end
     obj.currentSuper = nil;
     return obj;
 end

 function delete(obj)
     do
         local destory =
             function(c)
                 while c do
                     if rawget(c,"dtor") then
                         c.dtor(obj);
                     end

                     c = getmetatable(c);
                     c = c and c.__index;
                 end
             end
         destory(obj);
     end
 end