code: public static int indexOf(String text, int begin, int end, char target, Functor<Integer, Integer> extra) {
          return indexOf(text, begin, end, target, extra);
      }
docs: Returns the index within a string of the first occurrence of the specified character, similar to String.indexOf().
  However, any occurrence of the specified character enclosed between balanced parentheses/brackets/braces is ignored.
  
  @param text a String
  @param begin a begin offset
  @param end an end offset
  @param target the character to search for
  @param extra an optional functor to provide balancing symbols in addition to the standard ones
  @return the index of the character in the string, or -1 if the specified character is not found