The standard library Interval_Domain api defines the argument type for the interval_set_g defined in src/lib/src/interval-set-g.pkg.
The Interval_Domain api source code is in src/lib/src/interval-domain.api.
The above information is manually maintained and may contain errors.
api { Point ;
compare : (Point , Point) -> Order;
next : Point -> Point;
prior : Point -> Point;
is_succ : (Point , Point) -> Bool;
min_pt : Point;
max_pt : Point;
};