<compile-time while statement>

── ̍WHILE ──<compile-time Boolean expression>── DO ────────────────────►
►─<compile-time statement>─────────────────────────────────────────────┤

The 'WHILE statement provides iterative compilation of ALGOL source input. The compile-time Boolean expression is evaluated at the beginning of the statement. If it is TRUE, the compile-time statement is processed, the compile-time Boolean expression is evaluated again, and this sequence is repeated. Whenever the compile-time Boolean expression is FALSE, the 'WHILE statement is finished, and compilation continues with the following statement.