delete(A, [A|B], B).
delete(B, [A|C], [A|D]) :-
delete(B, C, D).
add(A, B, [A|B]).
make_node(Name,List) :-
add(element(Name, [], []), [], List),
X=..List,
assert(X),
write(List).
make_node(Name, Attr, Cont, List) :-
add(element(Name, Attr, Cont), [], List),
X=..List,
assert(X),
write(List).
add_child(Parent,Child,Nlist):-
element(Parent,A,C),
retract(element(Parent,A,C)),
add(element(Child,[],[]),C,L),
make_node(Parent,A,L,Nlist).
add_child(Parent,Child,Ch_att,Ch_cont,Nlist):-
element(Parent,A,C),
retract(element(Parent,A,C)),
add(element(Child,Ch_att,Ch_cont),C,L),
make_node(Parent,A,L,Nlist).
make_list(List) :-
bagof(A,element(A,B,C),A),
L=..A,
add(element(L,B,C),[],List),
write(List).
save :-
tell('wiedza.pl'),
listing(element),
told.
prolog2xml(List,File):-
tell(File),
open(File,write,S),
xml_write(S,List,[]),
told,
close(S).
----------------------------------
add_child(Parent,Child,Nlist):-
element(Parent,A,C),
element(Child,Chatt,Chcont),
retract(element(Parent,A,C)),
retract(element(Child,Chatt,Chcont)),
add(element(Child,Chatt,Chcont),C,L),
make_node(Parent,A,L,Nlist).
add_child(Parent,A,Child,Chatt,Nlist):-
element(Parent,A,C),
element(Child,Chatt,Chcont),
retract(element(Parent,A,C)),
retract(element(Child,Chatt,Chcont)),
add(element(Child,Chatt,Chcont),C,L),
make_node(Parent,A,L,Nlist).
add(A, B, [A|B]).
add2end(X,[H|T],[H|NewT]):-add2end(X,T,NewT).
add2end(X,[],[X]).
append([], A, A).
append([A|B], C, [A|D]) :-
append(B, C, D).
remove(A, [A|B], B).
remove(B, [A|C], [A|D]) :-
remove(B, C, D).
belongs(*,[]).
belongs(X,[X|_]).
belongs(X,[_|Yogon]) :-
belongs(X,Yogon).
first(E,L) :-
append([],[E|_],L).
take1(1,[X|_],X).
take1(X,[_|T],Z):-
Y is X-1,
take1(Y,T,Z).
take(X,L):-
belongs(X,L),
assert(X),
write(X).
max([], A, A).
max([H|T], A, M) :-
H > A,
max(T, H, M).
max([H|T], A, M) :-
H =< A,
max(T, A, M).