libloader

local preload = { }
local loaded = { }
local searchers = { }
local searchpath
searchpath = function(name, path, sep, rep)
  if sep == nil then
    sep = "."
  end
  if rep == nil then
    rep = "/"
  end
  local err = "Could not find " .. tostring(name) .. "\n"
  local currDir = shell.getRunningProgram()
  path = path:gsub("%./", tostring(currDir) .. "/")
  name = name:gsub("[" .. tostring(sep) .. "]", rep)
  path = path:gsub("[?]", name)
  for test in path:gmatch("[^;]+") do
    if fs.exists(test) and not fs.isDir(test) then
      return test
    else
      err = err .. "  " .. tostring(test) .. "\n"
    end
  end
  return nil, err
end
local preloadSearcher
preloadSearcher = function(name)
  if package.preload[name] then
    return package.preload[name]
  end
  return nil, "Could not find " .. tostring(name) .. " in package.preload"
end
local simplePathSearcher
simplePathSearcher = function(name)
  local path = searchpath(name, package.path)
  return dofile, path
end
table.insert(searchers, preloadSearcher)
table.insert(searchers, simplePathSearcher)
require = function(name)
  local errors = { }
  if not loaded[name] then
    local loader = nil
    local arg = nil
    for _, searcher in ipairs(searchers) do
      loader, arg = searcher(name)
      if loader ~= nil then
        break
      else
        table.insert(errors, arg)
      end
    end
    if loader ~= nil then
      local status, res = xpcall(function()
        return loader(arg)
      end, function(err)
        return "An error occured while loading " .. tostring(name) .. " " .. tostring(tostring(err))
      end)
      if (not status) then
        error(res)
      end
      loaded[name] = res or { }
    else
      local errStr = "Failed to load module " .. tostring(name) .. "\n"
      for _, err in ipairs(errors) do
        errStr = errStr .. tostring(err) .. "\n"
      end
      error(errStr)
    end
  end
  return loaded[name]
end
package = {
  preload = preload,
  searchers = searchers,
  loaded = loaded,
  path = "./?.lua;./lib/?.lua;./lib/?;./bin/?.lua;./bin/?;/lib/?.lua;/lib/?;/bin/?.lua;/bin/?",
  searchpath = searchpath
}
return {
  setPath = function(path)
    package.path = path
  end
}