local imported = {}
local path = nil

local function package_stub(name)
  local stub = {}
  local stub_meta = {
    __index = function(_, index)
      error(string.format("member `%s' is accessed before package `%s' is fully imported", index, name))
    end,
    __newindex = function(_, index, _)
      error(string.format("member `%s' is assigned a value before package `%s' is fully imported", index, name))
    end,
  }
  setmetatable(stub, stub_meta)
  return stub
end

local function locate(name)
  local path = path
  if type(path) ~= "string" then
    path = os.getenv "LUA_PATH" or "./?.lua"
  end
  for path in string.gfind(path, "[^;]+") do
    path = string.gsub(path, "?", name)
	print(path)
    local chunk = loadfile(path)
    if chunk then return chunk, path end
  end
  return nil, path
end

function setpath()
	path = string.sub(debug.getinfo(2).source, 2, lastindexof(debug.getinfo(2).source, "/"))
end

function require(name)
  local package = imported[name]
  if package then return package end
  local chunk, path = locate(name)
  if not chunk then
	print(name .. path)
    error(string.format("could not locate package `%s' in `%s'", name, path))
  end
  package = package_stub(name)
  imported[name] = package
  chunk = chunk()
  setmetatable(package, nil)
  if type(chunk) == "function" then
    chunk(package, name, path)
  end
  return package
end