pub fn graph_union(left: &Graph, right: &Graph) -> GraphExpand description
The RDF merge of two graphs (left ∪ right). The standard way to build the
context graph the *_with_context repair entry points expect: the union of
a data graph and a shapes/ontology graph.
Cloning a graph copies its indexes wholesale, while inserting builds them a
triple at a time — so the larger side is always the one to clone, and only
the smaller side is inserted. Set union is commutative, so the result is
identical either way. Callers pass (data, shapes), and a shapes closure
routinely dwarfs the data graph (228k triples against 16 for a small Brick
model), which made the naive direction quadratically the wrong choice.