. @param expected vector of acceptable tokens, if available.
. */
. public void yyerror (string message, string[] expected) {
-. if ((expected != null) && (expected.Length > 0)) {
+. 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]);