<compile-time for statement>

── ̍FOR ──<number identifier>── := ────────────────────────────────────►
►─<compile-time arithmetic expression>── STEP ─────────────────────────►
►─<compile-time arithmetic expression>── UNTIL ────────────────────────►
►─<compile-time arithmetic expression>── DO ──<compile-time statement>─┤

The 'FOR statement provides iterative compilation of ALGOL source input. The value of the compile-time arithmetic expression following STEP can be positive or negative but must not be equal to zero.

The action of this statement is similar to that of the noncompile-time FOR statement. One exception is that the compile-time arithmetic expressions following STEP and UNTIL are evaluated only once, at the beginning of the 'FOR statement, and are not reevaluated, even though their compile-time components can change value.