Module is_empty 

is_empty(&g) — true iff num_points(g) == 0.

Mirrors boost::geometry::is_empty from boost/geometry/algorithms/is_empty.hpp. Boost’s contract is exactly num_points(g) == 0 (boost/geometry/test/algorithms/is_empty.cpp:74: BOOST_CHECK_EQUAL(detected, bg::num_points(geometry) == 0)), so this leans on crate::num_points::num_points rather than re-walking the kind hierarchy. Singletons (Point / Box / Segment) always return false because they carry an implicit point set.

Functions

is_empty

True iff g has no points.