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From: lsr@Apple.com (Larry Rosenstein)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Gripes about System 7.0
Message-ID: <11848@goofy.Apple.COM>
Date: 24 Jan 91 23:23:33 GMT
References: <20283@unix.SRI.COM> <5611@idunno.Princeton.EDU> <11827@goofy.Apple.COM> <5659@idunno.Princeton.EDU>
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Organization: Apple Computer, Inc.
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In article <5659@idunno.Princeton.EDU>, bskendig@dry.Princeton.EDU (Brian Kendig) writes:
> 
> And if I try to open, say, a MacWrite document, there is a built-in
> way to tell the Mac to open it with Microsoft Word, right?  I mean,
> it's certainly not going to tell me the obvious that it can't find
> MacWrite, is it?

If you change the magic resource, then the Finder will put up an alert
asking if it's OK to substitute the alternative application.  This might
be desirable, if you open something unintentionally, or if the application
is on removable media/file server where it might be available sometimes.
If Word were to add an FREF resource for MacWrite documents, then you
could drop a MacWrite document onto the Word app (or an alias).

I too wanted to implement a way to bypass the alert, for cases like 
Illustrator 3.0 which has a different signature than Illustrator 88.  My
first try was to add an entry to the Desktop DB (to use your example) for
MacWrite's signature but refer to the Word application.  The Finder would
look up the application to use and launch Word instead of MacWrite.
(In my case, I patched the call that looks up information in the DB and
switched signatures there.)

This all worked fine in most cases.  The MacWrite documents would even
be identified as Word documents.  (You could also add icons for the
MacWrite documents.)  The problem is that if Word was already running, then
double clicking a MacWrite document wouldn't work.  The problem seemed
to be that there was no running app with MacWrite's signature, but the
Word file was busy and couldn't be launched.

> Will the Finder be smart enough to add a resource to, say, the Desktop
> file to record that all MPNT (or whatever the creator code is) files
> are created by MacPaint?  And what good is this information, save for
> seeing "MacPaint document" in the directory window, unless it knows
> that I want to open all MacPaint documents with SuperPaint instead?

I don't think the Finder will add stuff like this to the Desktop DB.  I
think you would need some kind of user confirmation that you want to do this,
and then the problem is turning it off if you later get a copy of MacPaint.
There are significant user interface issue that would have to be addressed.

> It just bothers me that the method of finding an application to open a
> document should be handled a wee bit more thoroughly -- especiall now

I think the current mechanism works well for the average user.  The 
Finder tells you what's happening and doesn't do anything behind your 
back.  The are some hooks in the system for a hacker to change things 
(perhaps not all the hooks one would like, but I think you can still do a
lot of stuff).

Larry