Repeat statements specify the repeated execution of a statement sequence depending on the value of a Boolean expression. The expression is evaluated after each execution of the statement sequence, and the repetition stops as soon as it yields the value TRUE. Hence, the statement sequence is executed at least once.

   RepeatStatement = REPEAT StatementSequence UNTIL expression.

Example:

   REPEAT
      k := i MOD j;
      i := j;
      j := k;
   UNTIL j = 0

Source:

Wirth N: Programming in Modula-2, 3rd ed. Springer Verlag, Berlin, 1985.