DouKaku?

pokerHand([X,X,X,X,X], R, 'Royal flush') :-
    permutation(R, ['T','J','Q','K','A']).

pokerHand([X,X,X,X,X], R, 'Straight flush') :-
    sub_atom('A23456789TJQK', _, 5, _, A),
    atom_chars(A, P), permutation(R, P).

pokerHand([X,X,X,X,X], _, 'Flush').

pokerHand(_, R, 'Straight') :-
    sub_atom('A23456789TJQKA', _, 5, _, A),
    atom_chars(A, P), permutation(R, P).

pokerHand(_, R, 'Four of a kind' ) :- permutation(R, [X,X,X,X,_]).
pokerHand(_, R, 'Full house'     ) :- permutation(R, [X,X,X,Y,Y]).
pokerHand(_, R, 'Three of a kind') :- permutation(R, [X,X,X,_,_]).
pokerHand(_, R, 'Two pair'       ) :- permutation(R, [X,X,Y,Y,_]).
pokerHand(_, R, 'One pair'       ) :- permutation(R, [X,X,_,_,_]).
pokerHand(_, _, 'No pair'        ).

poker(Card) :-
    atom_chars(Card, [S1,R1,S2,R2,S3,R3,S4,R4,S5,R5]),
    pokerHand([S1,S2,S3,S4,S5], [R1,R2,R3,R4,R5], H), !,
    writeln(H).