say(Lst) :- is_list(Lst), writeln(Lst).
say(S) :- say(S,[]).
say(S,P) :- string_concat(S, '~n', S1), format(S1,P).
?- say('hello').
hello
true.
?- say('hello ~w',[world]).
hello world
true.
?- say('hello ~w ~w',[new,world]).
hello new world
true.
