Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!crdgw1!galen!leue
From: leue@galen.crd.ge.com (Bill Leue)
Newsgroups: comp.sys.mac.hypercard
Subject: Re: checking for field existence?
Message-ID: <18322@crdgw1.crd.ge.com>
Date: 8 Apr 91 12:53:44 GMT
References: <1991Apr3.192733.28490@hubcap.clemson.edu>
Sender: news@crdgw1.crd.ge.com
Organization: General Electric Research & Development
Lines: 21

In article <1991Apr3.192733.28490@hubcap.clemson.edu> jcocon@hubcap.clemson.edu (james c oconnor) writes:
>I would like to be able to check to see if a field by a particular
>name exists.  Is this possible, or should I write an xcmd?
>
>Jim

I asked a similar question a couple of weeks ago and got lots of good
replies, so here's my chance to pay back my debt.

HC 2.0 (not earlier versions!) have a "there is" operator which will
do what you want.  An example for detecting a field on the current card:

if there is a card field "Foo" then...

You can easily extend this to detecting a field in the entire stack,
or any object (button, window, etc) using standard looping techniques.

-Bill Leue
leue@crd.ge.com