Difference between while and for

While and for are pretty similar, but sometimes you need to do a not recommended thing - change cycle boundaries.

In this situation while and for are different. For calculates boundaries once per run and while calculates boundaries on every iteration.

Consider this code sample:

set x = 5
for i=1:1:x {
     write "i: ", i,", x: ", x,!
     set x = x+1
}

You'll get this output:

i: 1, x: 5
i: 2, x: 6
i: 3, x: 7
i: 4, x: 8
i: 5, x: 9

Compare to while cycle:

set i = 1
set x = 5
while (i<=x) {
    write "i: ", i,", x: ", x,!
    set x = x+1
    set i = i+1
}

The output is infinite:

i: 1, x: 5
i: 2, x: 6
i: 3, x: 7
i: 4, x: 8
i: 5, x: 9
i: 6, x: 10
i: 7, x: 11
i: 8, x: 12
i: 9, x: 13
i: 10, x: 14

...