DO CASE

    DO CASE is a structured programming command that selects only one
    course of action from a set of alternatives.

Syntax

    DO CASE
       CASE <condition>
           <commands>
       [CASE <condition>]
           <commands>
       [OTHERWISE]
           <commands>
    ENDCASE

Usage

    ENDCASE terminates the DO CASE structure.  Command pairs such as DO
    CASE...ENDCASE, IF...ENDIF, and DO WHILE...ENDDO must be properly
    nested within DO CASE.  Nested DO CASEs are permitted.  There are no
    nesting limits within the DO CASE structure.

    CASE <condition> sets up a conditional statement for evaluation.  It is
    a logical expression such as A=B or numvar<11.  When <condition>
    evaluates to logical True, all subsequent commands are carried out
    until any one of the following commands is reached: another CASE,
    OTHERWISE, or ENDCASE.

    After one True CASE is found and its associated commands are processed,
    no further CASE statements are evaluated.  Program control will skip
    immediately to the first command after ENDCASE.  If no CASE statements
    evaluate to True, and there is no OTHERWISE statement, the program
    processes the first command following ENDCASE.  OTHERWISE causes the
    program to take an alternative path of action when all CASE statements
    evaluate to False.

    Note that like all other control structures, only the first three
    characters of the END statement are significant.

Tips

    In instances where only one of many conditions will evaluate to True,
    or where only the first True instance is to be processed, the DO CASE
    command is preferable to the IF command.

    The CASE construction is often used when there are a small number of
    exceptions to a condition.  The CASE <condition> statements can
    represent the exceptions, and the OTHERWISE statement the more common
    situation.