:- ensure_loaded( library(lists) ). % memberchk/2. opts_have_help( Opts ) :- opts_have_help( Opts, _Width ). opts_have_help( Opts, Width ) :- ( (memberchk(h,Opts);memberchk(help,Opts);Opts=h;Opts==help) -> ( memberchk(help_screen_width(Width),Opts) -> true ; Width is 80 ) ; ( (memberchk(h(W),Opts);memberchk(help(W),Opts); Opts=h(W);Opts==help(W)) -> Width = W ; fail ) ).