:- use_module(library(clpfd), except([in/2])).

:- op(950, fy, time).
:- op(900, xfy, at).
:- op(900, xfy, in).
:- op(950, xfy, for).

time Time at Bar :-
    time Time in range(From, To),
    Bar in range(From, To).

time Time at Bar :-
    time Time in range(From, To) for I in range(IFrom, ITo),
    Bar in range(From, To),
    I in range(IFrom, ITo).

I in range(From, To) :-
    I #>= From,
    I #< To.

% Uzivatel zadava:

time 6/8 in range(0, 4).
time 7/8 in range(4*K, 4*K+2) for K in range(1, 4).
time 4/4 in range(4*K+2, 4*K+4) for K in range(1, 4).

% Testovani v toplevelu:

% ?- time X at 3
% ?- time X at 4
% ?- time X at 5
% ?- time X at 6
% ...