WHILE

Generated from C.60.01 /SYS/PUB/CICAT last modified on Thu Jan 11 09:18:52 2001

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WHILE

     WHILE causes the commands within a WHILE block to be executed
     repetitively as long as a specified condition is true.  A WHILE
     block consists of all the commands between the WHILE and ENDWHILE
     commands. (NM)

SYNTAX

     WHILE expression [DO]

PARAMETERS

expression          Logical expression, consisting of operands and
                    relational operators.  The DO keyword is optional.
                    It may be used or omitted and has no affect on the
                    results.

                    The WHILE command evaluates expression and displays
                    the result (TRUE or FALSE) to $STDLIST. If
                    expression does not resolve to a boolean result,
                    an error is reported.

OPERATION

     This command begins a looping construct that consists of
     all the commands lying between WHILE and the next ENDWHILE
     statement.  The ENDWHILE must have the same nesting level
     as the WHILE statement.  The ENDWHILE statement ends the
     WHILE block.

     Expression is evaluated and as long as expression
     evaluates to TRUE, the WHILE block is executed.

     You may not write a WHILE construct in such a way that a WHILE
     begins in one User Command (UDCs or command files) and its
     corresponding ENDWHILE concludes the loop in another User
     Command.

     o  To see a list of expression evaluator functions, type
        FUNCTIONS at the HELP prompt.  Or, you may enter an
        individual function name for more specific information.

     o  To see a list of FINFO options, type FINFO at the HELP prompt.

     o  To see a list of predefined MPE/iX variables, type VARIABLES
        at the HELP prompt.  Or, you may enter an individual variable
        name for more specific information.

     This command may be issued from a session, job, in BREAK, or
     from a program.  Pressing [Break] aborts the execution of
     this command.

EXAMPLE(S)

The following is an example of the WHILE command:

     WHILE SETVAR (filename, input("Enter the next filename &
     to purge: ")) <> "" DO
     CONTINUE
     PURGE !filename
     ECHO ![ups(filename)] has been purged.
     ENDWHILE

This section of code will continue to ask for and purge files until the
user enters a [Return] or the name of a file that does not exist.

ADDITIONAL INFORMATION

Commands:   DELTEVAR, ELSE, ELSEIF, ENDWHILE, IF, RETURN,
            SETJCW, SHOWJCW, SETVAR, SHOWVAR; see also FUNCTIONS
            and VARIABLES

Manuals :   Appendix B, "Expression Evaluator Functions," in the
            MPE/iX Commands Reference Manual (32650-90003)


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