code: public AsciiString[] split(String expr, int max) {
          return toAsciiStringArray(Pattern.compile(expr).split(this, max));
      }
docs: Splits this string using the supplied regular expression {@code expr}. The parameter {@code max} controls the
  behavior how many times the pattern is applied to the string.
  
  @param expr the regular expression used to divide the string.
  @param max the number of entries in the resulting array.
  @return an array of Strings created by separating the string along matches of the regular expression.
  @throws NullPointerException if {@code expr} is {@code null}.
  @throws PatternSyntaxException if the syntax of the supplied regular expression is not valid.
  @see Pattern#split(CharSequence, int)