While loops

While loops are also similar as Java's. You can also provide any expression in them as you would in a Marcel if. If the provided expression is not a boolean, the Marcel truth will decide if your expression is true or not.

int i = 0
while (i < 10) {
  println(i++)
}

while variable declaration

The marcel truth allows you to declare variable in an while condition, and execute the code block if the variable is truthy

while (String line = reader.readLine()) println(line)

// outside the loop, this line variable doesn't exist anymore

Do while

You can also perform do-while instructions, which will always execute at least one the do statement and then check the condition. If the condition is true the do statement is executed again.

int i = 15
do {
  println(i++)
} while (i < 10)

The above code will only print 15.

Do

You can specify a do instruction without a while instruction at the end. It will just execute the do statement once. This can be useful to create inner scopes, in which you can create all the local variables you want, as they won't be accessible outside the do scope

int result = 5
do {
  int variable = 1
  int anotherVariable = 2
  int anotherOtherVariable = 3
  int anotherOne = 5
  result = variable + anotherVariable + anotherOtherVariable + anotherOne
}

// now only result variable exists