Syntax options:

       IN value-expr TO value-expr
       IN REVERSE value-expr TO value-expr

    Specifies how often the compound-use-statement should be
    executed. When the REVERSE keyword is not specified, the variable
    contained in the FOR variable-name is incremented at the end of
    each execution of the FOR loop body. When the REVERSE keyword
    is specified, the variable contained in the FOR variable-name is
    decremented at the end of each execution of the FOR loop body.

    Both value expressions are evaluated once before the loop
    executes. The TO value-expression is evaluated first to ensure
    that references to the FOR loop variable do not cause side
    effects.