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From: stm@apple.com (Steve Maller)
Newsgroups: comp.sys.mac.hypercard
Subject: Re: EvalExpr() callback in XCMDs
Message-ID: <9062@goofy.Apple.COM>
Date: 9 Jul 90 21:20:02 GMT
References: <2608@network.ucsd.edu>
Sender: usenet@Apple.COM
Organization: Apple Computer, Inc.
Lines: 17

In article <2608@network.ucsd.edu> pbiron@weber.ucsd.edu (Paul Biron) 
writes:
> A while back I asked if there was a way to tell if an
> arbitrary object existed (e.g. if Exists (cd fld "foo") then ...).

HyperCard 2.0 contains a HyperTalk function called "there is a". For 
example, you can say
  if there is a card button id 4
  if there is a file "MyDisk:Fred"
  if there is a window "Variable Watcher"
Obviates the need for any more such monkeying around...

Steve Maller
Software Engineer
Apple Computer

I yam what I yam...