replaced Symbol.is_hex_letter to Symbol.is_ascii_hex; tuned Symbol.is_ascii_blank (according to SML syntax);
replaced Symbol.is_hex_letter to Symbol.is_ascii_hex;
tuned Symbol.is_ascii_blank (according to SML syntax);

MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle