:- module backjump.
:- interface.
:- type choice_id.
:- impure pred backjump(backjump.choice_id).
:- mode backjump((builtin.in)) is erroneous.
:- impure pred get_choice_id(backjump.choice_id).
:- mode get_choice_id((builtin.out)) is nondet.
:- func to_int(backjump.choice_id) = int.
:- implementation.
:- type choice_id == int.
