odd(N) :- 1 is mod(N, 2). even(N) :- 0 is mod(N,2).
odd(12) even(9)
GNU Prolog 1.3.1
By Daniel Diaz
Copyright (C) 1999-2009 Daniel Diaz
uncaught exception: error(syntax_error('user_input:3 (char:1) . or operator expected after expression'),read_term/3)