-- main.mcl --
import "os"
$apply1 = func($f, $x) {
	$f($x)
}
$apply2 = func($f, $x) {
	$f($f($x))
}
$apply = if (os.system("echo 0; echo 1") == "0") {$apply1} else {$apply2}
$id = func($y) { $y }

# since $apply changes over time, this call needs a dynamic sub-graph. In
# theory, the $f calls above do not need a sub-graph, but does our optimization
# support this corner case yet?
$name = $apply($id, "foo")
test "${name}" {}
-- OUTPUT --
Vertex: test[foo]