Function expression_returns_set

src/backend/nodes/nodeFuncs.c:729–733

* expression_returns_set * Test whether an expression returns a set result. * * Because we use expression_tree_walker(), this can also be applied to * whole targetlists; it'll produce true if any one of the tlist items * returns a set. */

 * returns a set.
 */
bool
expression_returns_set(Node *clause)
{
	return expression_returns_set_walker(clause, NULL);
}

static bool
expression_returns_set_walker(Node *node, void *context)