if Current_app == nil or Current_app == 'run' then
    return {
      write = function(self, ...)
                local args = {...}
                for i,s in ipairs(args) do
                  App.filesystem[filename] = App.filesystem[filename]..s
                end
              end,
      close = function(self)
              end,
    }
  elseif Current_app == 'source' then
    return {
      write = function(self, s)
                App.filesystem[filename] = App.filesystem[filename]..s
              end,
      close = function(self)
              end,
    }
  end

  return {
    write = function(self, s)
              App.filesystem[filename] = App.filesystem[filename]..s
            end,
    close = function(self)
            end,
  }