Question

How to close an input stream in SWI-Prolog using <CTRL>+<D> combination ?

bot:-
   repeat,
     write('>'),
     readln(X), nl,
     answer(X, Answer),
     write(Answer), nl,
    end(X).

end(X):-member('end',X).

Where X is a list of keywords to that bot

How should I modify source code to get that result?

Answer 1

I have already found a solution.
To get that result I have to apply at_end_of_stream and cut “!“.

bot:-
    write('Hello'),
    nl,
    write('>'),
    repeat,
    readln(X),
    answer(X, Answer),
    write(Answer),
    nl,
    write('>'),
    at_end_of_stream, !.

Last two lines of code makes it works as I expect.
Now when using combination Ctrl+D we can stop it (close stream which is the same what turning bot off).

@larsmans: Nice to know that readln is bad or just not optimal. Maybe next time I will use that tip. 🙂