:- module(_,_).

% ISO-Prolog arithmetic

%% Examples of success:

% Try:
% ?- X is 3*3//2.
% ?- Z = 3//2, X is 3+Z.


%% Examples of failure:

% Try:
% ?- X=3, Y=4, Y < X+1.
% ?- X=3, Y=4, X is Y+1.
% ?- X=3, Y=4, X =:= Y.

%% Examples of error: 

% Try: 
% ?- X is 3+Y.
% ?- Y=4, Y < a+1.
% ?- X is Z+1.
% ?- X=3, X =:= f(a).