Loops

Implemented

while

var count = 3
while count > 0 {
    print(count)
    count = count - 1
}

Target	Output
Python	`while count > 0:`
JavaScript	`while (count > 0) {`
Go	`for count > 0 {`

The Go emitter rewrites while to for, which is why this still compiles for Go.

for (classic)

for var i = 0; i < 5; i = i + 1 {
    print(i)
}

The Go emitter rewrites it to for i := 0; i < 5; i++ {; JavaScript gets for (let i = 0; i < 5; i++) {; Python gets a while loop with manual counter.

for … in (foreach)

The foreach keyword (or for k, v in coll) iterates collections:

var nums = [10, 20, 30]
foreach n in nums {
    print(n)
}

Target	Output
Python	`for n in nums:`
JavaScript	`for (n of nums) {`
Go	`for _, n := range nums {`

Two-variable form iterates maps/entries:

var scores = {"Ada": 90, "Grace": 85}
foreach name2, score in scores {
    print(name2, score)
}

do … while

Runs the body at least once:

var i = 0
do {
    print(i)
    i = i + 1
} while i < 3

Target	Output
Python	`while True:` + manual break on condition
JavaScript / Go	`do { … } while (i < 3);`

break / continue

foreach n in nums {
    if n == 0 {
        break
    }
    if n < 0 {
        continue
    }
    print(n)
}

Maps directly to each target's native keywords.