code: func NewWithLimit(expr string, size uint) (*Regexp, error) {
  	parsed, err := syntax.Parse(expr, syntax.Perl)
  	if err != nil {
  		return nil, err
  	}
  	return NewParsedWithLimit(expr, parsed, size)
  }
docs: // NewRegexpWithLimit creates a new Regular Expression automaton with
  // the specified expression.  The size of the compiled finite state
  // automaton exceeds the user specified size,  ErrCompiledTooBig will be
  // returned.