///   '?': matches a single non-'/' character
  ///   '[' [ '^' ] { match-list } ']':
  ///        matches any single character (not) on the list
  ///   c: matches character c (c != '*', '?', '\\', '[')
  ///   '\\' c: matches character c
  /// character-range:
  ///   c: matches character c (c != '\\', '-', ']')
  ///   '\\' c: matches character c
  ///   lo '-' hi: matches character c for lo <= c <= hi
  ///