code: @SuppressWarnings("squid:S1067")
      protected boolean isAtBracket(boolean inSymbol) {
          return input.current().is(brackets) || !inSymbol
                                                 && treatSinglePipeAsBracket
                                                 && input.current().is('|')
                                                 && !input.next().is('|');
      }
docs: Determines if the underlying input is looking at a bracket.
  <p>
  By default all supplied <tt>brackets</tt> are checked. If <tt>treatSinglePipeAsBracket</tt> is true, a
  single '|' is also treated as bracket.
  
  @param inSymbol determines if we're already parsing a symbol or just trying to decide what the next token is
  @return <tt>true</tt> if the current input is an opening or closing bracket