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From: nayeri@cs.umass.edu (Farshad Nayeri)
Newsgroups: comp.sys.mac.hypercard
Subject: Re: Trapping out Command-Period key presses.
Message-ID: <NAYERI.90Sep12192515@ibis.cs.umass.edu>
Date: 12 Sep 90 23:25:15 GMT
References: <7433@milton.u.washington.edu>
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Reply-To: nayeri@cs.umass.edu
Organization: Dept of Comp and Info Sci, Univ of Mass (Amherst)
Lines: 51
In-reply-to: bjornl@milton.u.washington.edu's message of 12 Sep 90 21:08:37 GMT

In article <7433@milton.u.washington.edu> bjornl@milton.u.washington.edu
(Bjorn Levidow) writes:

   Does anybody know how to trap out Command-Period key presses by the users?
   I have a stack where I want the user to do more than browse, so I can't
   have the stack locked, but I don't want them to be able to interrupt
   a script in the middle of execution.  Putting a trap in an idle handler
   could be done, but it would be cumbersome in my situation.  Any elegant
   solutions?  Thanks in advance.

I don't think there is anyway to do this directly from Hypertalk. I do have a
workaround that is not very elegant IMHO, but gets the job done using only
Hypertalk. I found out that usually cancelations involved breaking out of a
loop, so I wrote the following workaround:

  -- notice the code is written on the fly
  -- syntax might be wrong, but the idea is there

  put the msg into msgBack  
  -- ATP: what is the right way to use the message box anyway?

  on viewAllCards
    repeat for i = 1 to number of cds
      if the mouse is down then exit repeat -- also you can call handler
      put "visiting card"&&i&". [Hold mouse button down to cancel.]"
      go to cd i
    end repeat
  end viewAllCards

  put msgBack
  hide msg

It works. I am not sure if the ATP would approve it though (I kind of doubt
it...)  A better way is to use a non-modal dialog box (I originally thought
ShowDialog XCMD stack includes non-modal dialogs, but as far as I can see it
doesn't [Jay Hodgden, are you there?]) with Cancel button on it.  Kind of like
the way the old Print... command use to work on System version 4.0-.

As far as command-period discussion goes, I am not sure if it is even wise to
tell the novice user about command-period. That way they can break out of very
important scripts while they are running (for example openCard, etc...) and
weird things may happen to them. Note to people who have seen 2.0: is this
problem fixed?

      
      

--
Farshad Nayeri                Object Oriented Systems Group
nayeri@cs.umass.edu           Dept. of Computer and Information Science
(413)545-0256                 University of Massachusetts at Amherst