OO Utility

local function createClass(inherit)
    return setmetatable({},{__index=inherit})
end

local _type = _G.rawtype or type

_G["rawtype"] = _type

_G["type"] = function(obj)
    local type_ = rawtype(obj)
    if(type_ == "table") then
        if(obj._CLASS_NAME_) then
            return obj._CLASS_NAME_,true
        end
    end
    return type_
end

function _G.extendsFrom(from,to)
    local last = ""
    local cur = from
    if(cur.super) then
        while last ~= "BaseClass" do
            last = cur._CLASS_NAME_
            if(last == to) then
                return true
            end
            cur = cur.super
        end
    end
    return false
end

function _G.searchClassesExtending(from)
    local classes = {}
    for k,v in pairs(_G) do
    local t,isClass = type(v)
        if(isClass) then
            if(extendsFrom(v,from) and t~=from) then
                table.insert(classes,v)
            end
        end
    end
    return classes
end

function import(file)
    local handle = fs.open(file,"r")
    local cont = handle.readAll()
    handle.close()
    name,super = cont:match("--@Class ([^\t\n]+)"),cont:match("--@Extends ([^\t\n]+)")
    local env = {}
    env[name] = createClass(_G[super])
    env["super"] = _G[super] or _G["BaseClass"]

    local n = [[local new = function()
    return setmetatable(super:new(),{
        __index=]]..name..[[
        }) end
]]

    cont = n..cont
    env = setmetatable(env,{__index=_G})
    local f,err = loadstring(cont)
    if(err) then error(err,2) end
    setfenv(f,env)
    f()

    _G[name] = setmetatable(env[name],{__index=_G[super]})
    _G[name].super = _G[super]
    _G[name]._CLASS_NAME_ = name


end

local del = {}
for k,v in pairs(_G) do
    local _,y = type(v)
    if(y) then del[k] = true end
end

for k,v in pairs(del) do
    _G[k] = nil
end

_G["BaseClass"] = createClass{_OO_VERSION_ = 1,_CLASS_NAME_="BaseClass",new = function(self) return setmetatable({},_G["BaseClass"]) end}