:- initialization(run).
% uncaught exception: error(type_error(chars,[]),read_term_from_chars/2)
validcs --> [] | ( ";"|"A" ), validcs.

run :- run(_), fail.

run(T) :-
   _=[N,T],
   length(Cs,N),
   writeq(n(N)),nl,
   phrase(validcs,Cs),
   writeq(Cs),nl,
   catch(read_term_from_chars(Cs,T),error(syntax_error(_),_),fail).