topic Re: Case/switch statement in DCL in Operating System - OpenVMS

Case/switch statement in DCL

Fredrik.eriksson — Thu, 20 Nov 2008 12:46:49 GMT

A question I couldn't really find.
Is there any equivalent statement call to case/switch and is there something like linux "shift"?

Best regards
Fredrik Eriksson

Re: Case/switch statement in DCL

Robert Gezelter — Thu, 20 Nov 2008 13:19:28 GMT

Fredrik,

Yes. This is a question that is actually in the backlog for my OpenVMS Consultant column on OpenVMS.org (see http://www.openvms.org ).

The way that a case/switch (aka FORTRAN computed GOTO) is handled is via use of symbol substitution, to wit:

$ X = 15
$ ...
$ IF (X .LT. 0) .OR. (X. GT. 20)
$ THEN
$ .... (Error Processing) ...
$ ENDIF
$!
$ GOTO TARGET_'X'
$!
$ TARGET_0:
$ ...
$ GOTO TARGET_COMMON:
$!
$ TARGET_1:
$ ...
$ TARGET_20:
$ ...
$ TARGET_COMMON:

The usual tricks that can be done with this class of construct (e.g., coalescing different cases) are straightforward.

I hope that the above is helpful.

- Bob Gezelter, http://www.rlgsc.com

Re: Case/switch statement in DCL

Fredrik.eriksson — Thu, 20 Nov 2008 13:22:14 GMT

Thank you, that's what I thought. Was just hoping there was something like the linux case-statement, like this:
case $1 in
case-trigger)

;;
shift
esac

Best regards
Fredrik Eriksson

Re: Case/switch statement in DCL

Robert Gezelter — Thu, 20 Nov 2008 13:33:39 GMT

Fredrik,

With all due respect, there is no "linux case statement", it is a shell case statement.

There is a shell available on OpenVMS, is is available as part of the separate tools installation.

- Bob Gezelter, http://www.rlgsc.com

Re: Case/switch statement in DCL

Hoff — Thu, 20 Nov 2008 14:05:55 GMT

Or use the shell and the suite of shell tools that are available as part of the HP GNV download for OpenVMS, and write your shell scripts in bash.