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From: kem@h.gp.cs.cmu.edu (Kenneth Mohnkern)
Newsgroups: comp.sys.mac.hypercard
Subject: Re: if there is ... at [xx,yy]
Message-ID: <12556@pt.cs.cmu.edu>
Date: 1 Apr 91 16:20:15 GMT
References: <12497@pt.cs.cmu.edu)  <1991Mar30.180433.17363@ousrvr.oulu.fi)
Organization: Carnegie-Mellon University, CS/RI
Lines: 90

Thanks to everyone who sent me solutions to my request. Most didn't do
exactly what I wanted, but I appreciate the efforts. The person who came
closest to fulfilling my wishes was Ari Vaulo, who posted his solution
here.

It reads:
) my original problem:
) )  I guess HC2.0's "there is" doesn't have the ability to check if 
) )  there's an object at a certain point. The manual doesn't cover
) )  "there is" very well. I think it's only mentioned in a table of
) )  functions (or commands? properties?) I tried "If there is a bg 
) )  btn at 442,42 then beep". I got an error message.
) )  [blah, blah, blah...]
) 
) I solved that kind of problem by clicking at the point where I supposed 
) that there could be a button or something else. But it requires special
) code on every possible target. First I tried (with HC 2.0) the following
) command:
)     click at xloc,yloc
) It was easy to look using TARGET function which object was at location
) (xloc,yloc), but it was a bit harmful because it executes all the mouse*
) command handlers and I should modify the command with shift,command, and
) option keys:
)     click at xloc,yloc with cmdkey
) 
) and in possible targets
) 
)   on mouseUp
)      if the cmdKey is "down" then
)         exit mouseUp
)      else
)         {code what the button should normally do}
)      end if
)   end mouseUp
) 
) And at last I found that the possible solution isn't elegant, but it works.
) You should put the following code in your script where you want to find
) other objects:
)    
)     ...
)     global KLIKATTU,OSUMA
)     put empty into OSUMA
)     put "Joo" into KLIKATTU
)     click at xloc,yloc
)     put empty into KLIKATTU
)     if OSUMA is not empty then
)        {the name of the object located at xloc,yloc is in variable OSUMA}
)        {and it could be anything card, button, field, and so on.
)     ...
) 
) And in every object where is either some mouse* handlers or are your
) possible targets you should put the following code:
) 
)    on mouseUp
)       global KLIKATTU
)       if KLIKATTU is empty then
)          {code what the object should normally do}
)       else
)          global OSUMA
)          put the name of me into OSUMA
)          exit mouseUp 
)       end if
)    end mouseUp
) 
) I don't like global with object oriented like code, but sometimes it is MUST.
) I'm trying to do draughts (or checkers) game with HC (I'm not sure that it
) will be ever ready) and there I need this kind of scripts.
) 

This is a pretty complex solution. I thought something like just:
	(in the card script)
	on mouseUp
	  ...
	  put theDesiredLocation into dLoc
	  click at dLoc
	  if the target contains "useful button" then
	    -- I've found something good.
	  else exit mouseUp
	  -- or do something else...
	end mouseUp

I'll fool with it a little and see where this gets bad results and why
I'll need to use Ari's solution.

Again, thanks to all.

	ken
-- 

ken mohnkern#the robotics institute#carnegie mellon univ#pittsburgh pa