local function metatable(folder_name)
    return setmetatable({}, {
        __index = function(tbl, key)
            local status, result = pcall(require, ('Trans.%s.%s'):format(folder_name, key))

            if not status then
                error('fail to load: ' .. key .. '\n' .. result)
            end

            tbl[key] = result
            return result
        end
    })
end

local M = metatable('core')


M.metatable = metatable
M.style     = metatable("style")
M.wrapper   = metatable("wrapper")
M.backend   = metatable("backend")
M.frontend  = metatable("frontend")


M.cache = {}
return M