let tup = (
(1,2,3,4,5),
(2,3,4,5,6),
(3,4,5,6,7),
)
var count = 0
for let a, (var b), c, d... in tup do
b += 2*a
print(a, b, c, d)
if count == 0 then
assert a == 1
assert b == 4
assert c == 3
assert d == (4,5)
elif count == 1 then
assert a == 2
assert b == 7
assert c == 4
assert d == (5,6)
elif count == 2 then
assert a == 3
assert b == 10
assert c == 5
assert d == (6,7)
end
count += 1
end