Re: ALTER design (Was: Code problems with Perform Thru Exit causes fallthrough)

LX-i <lxi0007@netscape.net> wrote in message
 news:4MWdnUDRHLIlPTPbnZ2dnUVZ_h2pnZ2d@co
mcast.com...
>
> OK - here's a question for you old guy... er, seasoned professionals...
>
<snip>

> Now my curiosity is more theoretical.  How does one think to design
> ALTER in a good way?
>

An example that struck me as sensible at the time was to handle EOF in an
out-of-line file read: it's a long time ago so I don't recall the exact
details but it was something like this:

READ.

READ FILE AT END MOVE HIGH-VALUES TO FILE-KEY
ALTER READ TO PROCEED TO READ-X
GO TO READ-X.
(A bunch of other code)
READ-X.
EXIT.

As I say I can't recall the details; this construct did solve whatever the
problem statement was and did not cause too much strain on the maintainer
since the target of the ALTER was right there.  I do remember being a bit
nervous about the compiler's ability to handle the paragraph-name READ both
as a PERFORM target and an ALTER target, but there were never any problems.

PL