Prolog if-elseif-else -

as question says, thats kind of wanna simulate in prolog. i'm making game,here's code:

move(x):-     get_char(y)     get_char(_),     get_char(z),     not(oldloc='z'),     not(newloc = 'z'),     validmove(oldloc,newloc). move(_):-     write('thanks playing!'), nl. move(x):-     write('invalid move!'), nl,     write('try again?'), nl,     move(x). 

what want if first predicate check fails @ not(oldloc='z'),not(newloc = 'z'), go next predicate move(_) , fails @ validmove(oldloc,newloc) go next move(x). i'm new prolog , i'm clueless.

if-then-else: http://www.swi-prolog.org/pldoc/doc_for?object=send_arrow/2

another if-then-else: http://www.swi-prolog.org/pldoc/doc_for?object=(*-%3e)/2

sample #1:

?- test = test -> print('truth') ; print('false'). truth 

sample #2:

?- test = test -> (test2 = test3 -> print('truth'); print('false2')); print('false'). false2