Yes, use the more modern (ISO) get_char/1 and get_code/1. With:

get_yes_or_no(Result) :- get_code(Char), % read a character get_code(_), % consume the Return after it interpret(Char,Result), !. % cut -- see text

you should get:

?- get_yes_or_no(Result). |: Y

Result = yes ?

yes ?- get_yes_or_no(Result). |: N

Result = no ?

yes ?- get_yes_or_no(Result). |: l

Type Y or N:l

Type Y or N:l

Type Y or N:l

Type Y or N:Y

Result = yes ?

yes ?-

You can get a loop if you use get_char/1 instead of get_code/1 since interpret/2 (which expects an ascii code) will fail before the cut and execution will go to the second clause.

Hope this helps!