<compile-time let statement>

── ̍LET ──<compile-time variable>── := ────────────────────────────────►
►─<compile-time arithmetic expression>─────────────────────────────────┤

The 'LET statement is used to modify the value of a compile-time variable. If the compile-time variable was declared using the <vector length> construct, it must be subscripted by a compile-time arithmetic expression with a value in the range 0 to (vector length - 1).