   # within the respective
   # option list, such as `@_long'
   _catchSpaceDelimArgs: (opt, list) =>
+    @_optError(list, opt)
     if list[opt.arg].type isnt 'flag'
       if opt.optarg is undefined
         @_args.forEach((nonOpt, ind) =>

        ++elem.index)
    return list

  _splitCombinedShorts: () =>
    @_opts.forEach((elem, ind) =>
      dashes = elem.arg.replace(/^(--?).*/, '$1').length # number of dashes

      return self))

  _optError: (parent, child) =>
    console.log parent
    if parent[child.arg] is undefined
      if child.length < 2
        console.error("#{@app}: invalid option -- '#{child.arg}'")
        process.exit(1)
      else
        console.error("#{@app}: unrecognized option '--#{child.arg}'")
        process.exit(1)

  _parentError: () =>
