Add minetest.env:set_nodes()
The arguments are a table of the nodes to be set with the corresponding
positions:
{{pos = pos1, node = node1}, {pos = pos2, node = node2}, ...}
You can also set whole areas and mix them with normal positioned nodes:
{{minp = minp1, maxp = maxp1, node = node1}, {pos = pos2, node = node2},
...)
Using set_nodes() instead of set_node() is faster for cuboids or lots of
nodes.