var f = nil
fun f1()
let a = "a"
fun f2()
let b = "b"
fun f3()
let c = "c";
fun f4()
print("a:", repr(a))
print("b:", repr(b))
print("c:", repr(c))
assert "a" == a
assert "b" == b
assert "c" == c
end
nonlocal f = f4;
end
f3()
end
f2()
end
f1();
f();