# six is an identifier, implicitly = 0 if not specified
var six

var seven = 500

six = ((six + 4)) / 2
six *= 3 + 5 - 20 / 4  # shorthand operator assignment with bidmas precedence

# can be called `equals_7(6)`
# or `6.equals_7()`
fun equals_7(number)
    number is 7

# fib: 1,1,2,3,5,8,..
fun slow_fib(n)
    if n < 3
        return 1
    slow_fib(n-1) + slow_fib(n-2)

fun fast_fib(n)
    var its = 1
    var last
    var curr = 1
    while its < n
        var next = curr + last
        last = curr
        curr = next
        its += 1
    curr

var six = slow_fib(6) - fast_fib(3)

while seven > 7
    # divide by 10 until smaller than 7
    seven /= 10

loop
    # add 1 until its 7
    if seven % 8 is not 7
        seven = seven + 1
        continue
    break

if not seven.equals_7()
    # seven should be 7 by now
    six = -1
    seven = -1
else
    var seven = 11 # assignment shadowing in this scope
    seven *= 2

six * seven