Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!mips!apple!jkc
From: jkc@Apple.COM (John Kevin Calhoun)
Newsgroups: comp.sys.mac.hypercard
Subject: Re: Opening file with Multifinder (was openField handlers)
Message-ID: <52309@apple.Apple.COM>
Date: 2 May 91 15:53:31 GMT
References: <1991May1.181756.14689@midway.uchicago.edu> <52283@apple.Apple.COM> <1991May2.000016.27408@midway.uchicago.edu>
Organization: Apple Computer Inc., Cupertino, CA
Lines: 33


In article <1991May2.000016.27408@midway.uchicago.edu> jcav@quads.uchicago.edu
(john  cavallino) writes:

>But if all the products (Finder/Multifinder/Hypercard/MPW) are produced by
>the same company, wouldn't it make sense for the various software engineers
>to let each other in on their secrets?  Since Hypercard's ability to launch
>other applications is a very "system-software-ish" sort of thing, I still
>think it would have been nice to have implemented the Multifinder kludge.

There are two conflicting goals here:

1) knowing the secrets and getting cool stuff to work

2) maintaining an application that thousands of people use and that should
   not break under future releases of system software

Sometimes it's better not to exploit your knowledge of how things work at
the system level.  This is one of those cases.  All applications rely on
a published and supported interface to services that the system provides,
and to some degree they also rely on unpublished and unsupported things
that may change in a subsequent release of the system software.  If you
rely too heavily on the unsupported stuff, you might look like a hero for
a while, but you'll get caught with your pants down when System N.0 comes
out, and everybody will say you're a bozo.  (Unless you got x million
dollars for what you did. :-)

The MultiFinder fake-out, which is most often referred to here as
"MultiFinder puppet strings", has a big sign on it that says, "Angels
fear to tread here."

Kevin Calhoun
Apple Computer, Inc.