clpfd:fd_dom/2

/usr/local/lib/swipl/library/clp/clpfd.pl

library
- clp
  - clpfd.pl -- CLP(FD): Constraint Logic Programming over Finite Domains
    - in/2
    - ins/2
    - indomain/1
    - label/1
    - labeling/2
    - all_different/1
    - all_distinct/1
    - sum/3
    - scalar_product/4
    - #>=/2
    - #=</2
    - #=/2
    - #\=/2
    - #>/2
    - #</2
    - #\/1
    - #<==>/2
    - #==>/2
    - #<==/2
    - #/\/2
    - #\//2
    - #\/2
    - lex_chain/1
    - tuples_in/2
    - serialized/2
    - element/3
    - global_cardinality/2
    - global_cardinality/3
    - circuit/1
    - cumulative/1
    - cumulative/2
    - disjoint2/1
    - automaton/3
    - automaton/8
    - transpose/2
    - zcompare/3
    - chain/2
    - fd_var/1
    - fd_inf/2
    - fd_sup/2
    - fd_size/2
    - fd_dom/2
    - fd_degree/2
    - in_set/2
    - fd_set/2
    - is_fdset/1
    - empty_fdset/1
    - fdset_parts/4
    - empty_interval/2
    - fdset_interval/3
    - fdset_singleton/2
    - fdset_min/2
    - fdset_max/2
    - fdset_size/2
    - list_to_fdset/2
    - fdset_to_list/2
    - range_to_fdset/2
    - fdset_to_range/2
    - fdset_add_element/3
    - fdset_del_element/3
    - fdset_disjoint/2
    - fdset_intersect/2
    - fdset_intersection/3
    - fdset_member/2
    - fdset_eq/2
    - fdset_subset/2
    - fdset_subtract/3
    - fdset_union/3
    - fdset_union/2
    - fdset_complement/2
  - clpb.pl -- CLP(B): Constraint Logic Programming over Boolean Variables

fd_dom(+Var, -Dom)

Dom is the current domain (see in/2) of Var. This predicate is useful if you want to reason about domains. It is not needed if you only want to display remaining domains; instead, separate your model from the search part and let the toplevel display this information via residual goals.

For example, to implement a custom labeling strategy, you may need to inspect the current domain of a finite domain variable. With the following code, you can convert a finite domain to a list of integers:

dom_integers(D, Is) :- phrase(dom_integers_(D), Is).

dom_integers_(I)      --> { integer(I) }, [I].
dom_integers_(L..U)   --> { numlist(L, U, Is) }, Is.
dom_integers_(D1\/D2) --> dom_integers_(D1), dom_integers_(D2).

Example:

?- X in 1..5, X #\= 4, fd_dom(X, D), dom_integers(D, Is).
D = 1..3\/5,
Is = [1,2,3,5],
X in 1..3\/5.