)CS (number)

)CS followed by an integer from 0 to 7 establishes APL.68000 Level I or Level II mode. The Compatibility Setting is a workspace parameter and defaults to 0. See ⎕CS for details of the parameters. For example,

             )CS 0
             1 2 3[2]

generates a RANK ERROR whilst Compatibility Setting 1 (APL.68000 Level I mode) will return the result 2 for the same expression. The Compatibility Setting is a workspace parameter and defaults to 0