Subj : Translating CASE from BASIC to C++
To   : All
From : Mike Luther
Date : Wed Feb 07 2001 01:17 am

I've been faced with the job of translating everything from PowerBASIC to C++
in order to survive.  Like it or not I have to provide application
cross-platform compatibility between DOS, OS/2 and .. WIN-xx, if I go into
that.  I've also been advised by one client that the Feds told them that here
in the USA, 7 years of support have to be given for any old system when a new
one is implemented in certain medical applications with medical records.  I
don't represent that as gospel, only what I have been told to expect... ;)

Now .. the only way I can seemingly, perhaps, gain seven years of
cross-platform interoperability between OS/2, and DOS ... and shudder,WIN-xx ..
is with WATCOM V11(b) which I licensed along with the books, and where it may
go as version (c) etc., a long time ago.

So ..

I'm about 60% through writing an auto-translator from PowerBASIC 3.5 source to
Watcom V11 (b).  It's been educational.  One of the things that has been a
stumbling block to me is the use of CASE in BASIC where the switch logic is
based not on numeric conditionals, but alpha conditionals.

This surfaced in the OS/2 echo a bit ago with something that Sarah replied to.
I posted it in the Watcom Forum.  I'd like to attempt to re-look at the issue
here to see if anyting inspirational shows here please:


    1.) How can you handle CASE translations from BASIC to C++
        for OS/2, with emphasis on WATCOM V11(b) as the toolset?

    2.) SWITCH functions only with numeric logic, as I now think
        is the only way it works.  That's what I learned in the
        Watcom Forum when this question was posed there.

    3.) Based on what I learned from the Watcom Forum, my intitial
        translator algorithim was writtne to simply back-level
        all SELECT CASE in BASIC to the crude IF / THEN logic.

        Write the translator so that it converts the SELECT CASE
        to form a conditional master variable, based on what
        was used for the SELECT conditional variable.

        Re-design SELECT CASE as a parade of IF/THEN constructs.

That works fine for numeric-based stuff.  In my limited knowledge of C++, it
can degenerate into lots and lots of lines of code for non-numeric logic. It
still seems to me that handling strings ain't near so easy in C++ as it is in
BASIC, sigh..

Using the stock WATCOM libraries, remember this has to work across, DOS,OS/2
and .. shudder .. likely WIN-xx too, what do we do?  Suggestions would be
appreciated.  However, that's really unfair, isn't it? ;)

I think Sarah is faced with this same problem as well, but maybe not in WATCOM
V11, but some other compiler.  Thus the problem is generic?  But is sure is
OS/2 programming related, at least to me and I suspect others.


Thanks ..


Mike @ 117/3001

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