Path: utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!usc!apple!well!wdh
From: wdh@well.sf.ca.us (Bill Hofmann)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Idle and Hypercard 2.0
Message-ID: <22404@well.sf.ca.us>
Date: 3 Jan 91 17:11:42 GMT
References: <22363@well.sf.ca.us> <5542@rex.cs.tulane.edu>
Organization: Whole Earth 'Lectronic Link, Sausalito, CA
Lines: 33

In article <22363@well.sf.ca.us> wdh@well.sf.ca.us (Bill Hofmann) writes:
>Here's a question, since MacDTS is on (gasp!) vacation.  I have an XCMD
>which sits in a loop waiting for a condition to match or a timer to expire,
>but I'd like other processes *in* Hypercard to get time.  (That is, GNE or
>WNE won't do the trick.)  Should I SendCardMessage(paramPtr, 'idle')?  That
>doesn't seem to work.  Suggestions are welcome.

Thanks to all those who responded.  The biggest thing I learned what that I
phrased the question kind of wrong.  The purpose of the XCMD is to wait for
a condition to match, so it can't return in the meantime.  It's kinda like
the Toolbox routine Delay()-it's not the *best* way to do it, but it's the
easiest for a novice programmer.  I solved the problem, like so:

	do {
		...check condition...
		SendCardMessage(paramPtr, "\pidle"); /* yes, it *does* work */
		if (WaitNextEvent(everyEvent, &anEvent, 0, NIL) &&
			anEvent.what == keyDown &&
			AbortKeyTyped(&anEvent))
		    break;
		else
		    SendHCEvent(paramPtr, &anEvent)
	} while (!condition);

Since SendHCEvent gets called *every* time, even with nullEvents, the
SendCardMessage may be irrelevant, but what the hey.

Obviously, as some of you pointed out, Hypercard 2.0 provides a nice feature
for sort of multi-tasking, by letting an XCMD create a window and then letting
the window receive time as nullEvents.  In fact, that's what makes the rest of
the product (of which this pesky XCMD is one small part) work.

-Bill Hofmann