cond = True
s = if cond:
    do "then block"
    do "else block"
assert s == "then block"

if! cond:
    do!:
        print! "then block!"
    do!:
        print! "else block!"

a = [1, 2, 3]
sum = match a:
    [x, y, z] -> x + y + z
    ((x, y, z),) -> x + y + z
    {x; y; z} -> x + y + z
    (i: Int) -> i
    _ -> panic "unknown object"

for! 0..<1000, i =>
    print! "i = {i}"
    if i >= 100:
        do return break()

counter = !100
while! do!(not counter.is_zero()), do!:
    print! "counter = \{counter}"
    counter.dec!()
