I'm creating a text adventure game on SWI-Prolog and I want to include (some kind of) dialogs. What I have so far is: dialog1(1):- nl,write('blah blah'),nl write('a: this is answer a'),nl, write('b: this is answer b'),nl. a:- write('respond to answer a'),nl. b:- write('respond to answer b'),nl. That's pretty much the first dialog. Now I want to create a second dialog similar to the first one. dialog1(2):- nl,write('blah blah'),nl, write('a: this is answer a'),nl, write('b: this is answer b'),nl. a:- write('respond to answer a'),nl. b:- write('respond to answer b'),nl. How can I check if the dialog is the first or the second one? I want to do that because when the user types a., I need the right answer a to be shown. I thought I could use something like a(1):- write('respond to answer a'),nl. b(1):- write('respond to answer b'),nl. /* and on the second dialog*/ a(2):- write('respond to answer a'),nl. b(2):- write('respond to answer b'),nl. But still, if the user is on dialog 2 and he types a(1),the first answer will appear.