public void yyerror (string message, string[] expected) {
if ((yacc_verbose_flag > 0) && (expected != null) && (expected.Length > 0)) {
ErrorOutput.Write (message+", expecting");
for (int n = 0; n < expected.Length; ++ n)
ErrorOutput.Write (" "+expected[n]);
ErrorOutput.WriteLine ();
} else
ErrorOutput.WriteLine (message);
}