-- main.mcl --
import "fmt"

$map0 = {0 => "a", 1 => "b", 2 => "c"}
$map1 = {0 => "d", 1 => "e", 2 => "f"}
$map2 = {0 => "g", 1 => "h", 2 => "i"}
$map3 = {0 => "j", 1 => "k", 2 => "l"}

$map = {0 => $map0, 1 => $map1, 2 => $map2, 3 => $map3}

forkv $key, $val in $map {
	forkv $i, $v in $val {

		$s = fmt.printf("%s is %d", $v, $i + $key)
		test [$s] {}
	}
}
-- OUTPUT --
Vertex: test[a is 0]
Vertex: test[b is 1]
Vertex: test[c is 2]
Vertex: test[d is 1]
Vertex: test[e is 2]
Vertex: test[f is 3]
Vertex: test[g is 2]
Vertex: test[h is 3]
Vertex: test[i is 4]
Vertex: test[j is 3]
Vertex: test[k is 4]
Vertex: test[l is 5]
