111 lines
2.8 KiB
Prolog
111 lines
2.8 KiB
Prolog
|
|
:- initialization(yap_flag(tabling_mode, load_answers)).
|
|
% Required to activate rational term support within the table space.
|
|
|
|
/*
|
|
ICLP2014 submission - instack/2
|
|
*/
|
|
instack(E, [H|T]) :- E == H.
|
|
instack(E, [_H|T]) :- instack(E, T).
|
|
|
|
/*
|
|
ICLP2014 submission - Example 1. member_1/2
|
|
Cyclic safe predicate with the use of instack/2 predicate.
|
|
*/
|
|
member_1(E, L) :-
|
|
member(E, L, []).
|
|
|
|
member(E, [E|_T], _).
|
|
member(_E, L, S) :-
|
|
instack(L, S),
|
|
!,
|
|
fail.
|
|
member(E, [H|T], S) :-
|
|
member(E, T, [[H|T]|S]).
|
|
|
|
/*
|
|
ICLP2014 submission - Example 2. member_2/2
|
|
Cyclic safe predicate with the use of tabling.
|
|
*/
|
|
:- table member_2/2.
|
|
|
|
member_2(E, [E|_T]).
|
|
member_2(E, [_H|T]) :-
|
|
member_2(E, T).
|
|
|
|
/*
|
|
ICLP2014 submission - Example 3. bin/1
|
|
*/
|
|
:- table bin/1.
|
|
:- tabling_mode(bin/1, coinductive).
|
|
% The two above directives are the equivalent of the :- coinductive bin/1 directive
|
|
bin([0|T]) :- bin(T).
|
|
bin([1|T]) :- bin(T).
|
|
|
|
/*
|
|
ICLP2014 submission - Example 4. comember/2
|
|
*/
|
|
|
|
:- table comember/2.
|
|
:- tabling_mode(comember/2, coinductive).
|
|
% The two above directives are the equivalent of the :- coinductive comember/2 directive
|
|
comember(H, L) :-
|
|
drop(H, L, L1),
|
|
comember(H, L1).
|
|
|
|
:- table(drop/3).
|
|
drop(H, [H|T], T).
|
|
drop(H, [_|T], T1) :- drop(H, T, T1).
|
|
|
|
|
|
%%%%%%%%%%
|
|
/*
|
|
ICLP2014 submission - Example 5. alternative drop_2/3 definition.
|
|
This definition uses instack instead of tabling.
|
|
*/
|
|
|
|
drop_2(E, L, NL) :-
|
|
drop(E, L, NL, []).
|
|
|
|
drop(_E, L, _NL, S) :-
|
|
instack(L, S),
|
|
!,
|
|
fail.
|
|
drop(E, [E|T], T, _).
|
|
drop(E, [H|T], T1, S) :-
|
|
drop(E, T, T1, [[H|T]|S]).
|
|
|
|
/*
|
|
ICLP2014 submission - Example 6. canonical_term/2
|
|
The following predicate takes a rational term and returns
|
|
the same rational term in canonical form.
|
|
*/
|
|
|
|
canonical_term(Term, Canonical) :-
|
|
Term =.. InList,
|
|
decompose_cyclic_term(Term, InList, OutList, OpenEnd, [Term]),
|
|
Canonical =.. OutList,
|
|
Canonical = OpenEnd.
|
|
|
|
decompose_cyclic_term(_CyclicTerm, [], [], _OpenEnd, _Stack).
|
|
decompose_cyclic_term(CyclicTerm, [Term|Tail], [Term|NewTail], OpenEnd, Stack) :-
|
|
acyclic_term(Term), !,
|
|
decompose_cyclic_term(CyclicTerm, Tail, NewTail, OpenEnd, Stack).
|
|
decompose_cyclic_term(CyclicTerm, [Term|Tail], [OpenEnd|NewTail], OpenEnd, Stack) :-
|
|
CyclicTerm == Term, !,
|
|
decompose_cyclic_term(CyclicTerm, Tail, NewTail, OpenEnd, Stack).
|
|
decompose_cyclic_term(CyclicTerm, [Term|Tail], [Canonical|NewTail], OpenEnd, Stack) :-
|
|
\+ instack(Term, Stack), !,
|
|
Term =.. InList,
|
|
decompose_cyclic_term(Term, InList, OutList, OpenEnd2, [Term|Stack]),
|
|
Canonical =.. OutList,
|
|
( Canonical = OpenEnd2,
|
|
Canonical == Term,
|
|
!
|
|
; OpenEnd2 = OpenEnd
|
|
),
|
|
decompose_cyclic_term(CyclicTerm, Tail, NewTail, OpenEnd, Stack).
|
|
decompose_cyclic_term(CyclicTerm, [_Term|Tail], [OpenEnd|NewTail], OpenEnd, Stack) :-
|
|
decompose_cyclic_term(CyclicTerm, Tail, NewTail, OpenEnd, Stack).
|
|
|