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Control Flow

rev20220311

Conditions

If / Else 文

if statement evaluates a condition, if true, execute the first block. if false, evaluate else if conditions in order, first block whose condition is true is executed. If all conditions are false, else block is executed. else and else if blocks can be omitted.

fn fizzbuzz(n int) string {
  if n % 3 == 0 && n % 5 == 0 {
    return 'fizzbuzz'
  } else if n % 3 == 0 {
    return 'fizz'
  } else if n % 5 == 0 {
    return 'buzz'
  } else {
    return n as string
  }
}

assert(fizzbuzz(1) == '1')
assert(fizzbuzz(3) == 'fizz')
assert(fizzbuzz(5) == 'buzz')
assert(fizzbuzz(15) == 'fizzbuzz')

() is not required for conditions. But (expr) is a valid expression. so conditions with () work.

var n = 1
if n == 1 {
  echo("it works")
}
if (n == 1) {
  echo("it also works")
}

Conditions must be bool.

var n = 1

// OK
if n != 0 {
  echo(n)
}

// Error
if n {
  echo(n)
}

Loops

for-in statement

for in statement execute a block for each items of a enumerable value.

var n = 0
for v in [1, 2, 3] {
    n += v
}
assert(n == 6)

while statement

while statement execute a block until condition is no longer true.

var i = 0
while i < 10 {
  i += 1
}
assert(i == 10)

continue / break statement

You can use continue to go back to the beggining of current loop.

You can use break to exit current loop immediately.

for i in [1, 2, 3, 4, 5] {
  if i > 3 {
    break
  }
  if i % 2 == 0 {
    continue
  }
  assert(i <= 3 && i % 2 == 1)
}

continue and break apply to the innermost loop.

var n = 0
for v in [1, 2, 3] {
  while true {
    break
    assert(false)
  }

  n += v
}
assert(n == 6)

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