Path: utzoo!attcan!uunet!husc6!bbn!bbn.com!mesard
From: mesard@bbn.com (Wayne Mesard)
Newsgroups: comp.sys.mac.hypercard
Subject: Intercepting error messages
Message-ID: <40136@bbn.COM>
Date: 18 May 89 17:15:53 GMT
Sender: news@bbn.COM
Reply-To: mesard@BBN.COM (Wayne Mesard)
Organization: Bolt Beranek and Newman Inc., Cambridge MA
Lines: 31

When you try and copy an empty picture (using the Select tool and Copy
Picture) Hypercard gives an error message saying "Nothing to Copy.  Try
Background."  This is fine and dandy, except if you're doing the copying
from within a script (e.g., to move an image from one card to another,
like I'm doing).  In this case, the [possibly-Hypercard neophite] user
is unexpectedly confronted with this messsage.

I think the right thing is for ALL error messages to be handled the way
the "No such card" message is handled by the Go command:

   If a script is being executed then put the message in "the result"
   and keep running (whenever possible).  Otherwise [if it's a menu
   thing or a msg box thing] display it in a dialog box.

Of course this isn't backwards compatible.  So if this behavior were to
be put in a future release, I guess it would have to be contingent on
the value of some global variable, e.g. showErrors.

[Incidently, my solution is to put a single pencil click in the corner
of each card when it gets created.  But that's a hack, and it means that
my script may be doing a lot of work (and wasting a lot of the user's
time) stupidly moving around a blank image.]

If there's some existing way to get around this problem that I've
overlooked, please let me know.


-- 
unsigned *Wayne_Mesard();
MESARD@BBN.COM                       "POKE 144,85"
BBN, Cambridge, MA