if 'qual' is 'first', then the match succeeds only if the first value matches.
if 'qual' is 'not_first', then the match succeeds only if any value other than
the first matches.
if 'qual' is 'first', then the match succeeds only if the first value matches.
if 'qual' is 'not_first', then the match succeeds only if any value other than
the first matches.