Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!apple!dlyons
From: dlyons@Apple.COM (David Lyons)
Newsgroups: comp.sys.apple
Subject: Re: ProDOS v1.9
Message-ID: <34576@apple.Apple.COM>
Date: 7 Sep 89 22:34:12 GMT
References: <8909070837.AA12730@trout.nosc.mil>
Organization: Apple Computer Inc, Cupertino, CA
Lines: 45

In article <8909070837.AA12730@trout.nosc.mil> markl@pro-generic.cts.com (Mark Leumanne) writes:
>I think I confused alot of people, what  I was saying is, just to make it so
>that ProDOS's Bye, would be also be able to run Basic etc. files, you know,
>when you type 'BYE' all you can run from there is System files, which is not
>good, maybe I am mixing BASIC.SYSTEM with ProDOS, if so, whatever it is,
>doesn't anyone agree that All file types (that are 'Run-able') should be able
>to be accessed by the BYE?  

Yes, you're mixing ProDOS with BASIC.SYSTEM a bit.  BASIC.SYSTEM's "BYE"
command translates directly into a ProDOS "QUIT" call.

The built-in quit handler is compact and only lets you run SYS files, since
these are the only kind of "runnable" file that ProDOS defines.  For it to
run, for example, Applesoft BASIC files, it would have to know what application
to launch (BASIC.SYSTEM); that could be quite a trick, considering it doesn't
know what disk or what subdirectory to look in to find BASIC.SYSTEM, and you
there's no reason you can't change the name of BASIC.SYSTEM to something else.

BIN files are a worse problem, since you can't tell whether they're programs
or not, or what environment they expect to run under.

You might want to investigate "command shells" like ECP 8 (by Don Elton; now
freeware, I believe) and Davex (by me; Shareware).  With a command shell you
never have to deal with "enter prefix/pathname of next application"; instead,
when you quit one application, you're automatically back in the Shell, at a
command prompt.  From there you have quite a few options for launching
various kinds of files.

Other sorts of program selectors are available too, like the one in Glen
Bredon's ProSel package.  (The ProSel selector is mostly menus, rather than
command lines.)

Program selectors are possible because there is a documented way to replace
the "quit code" (the "enter prefix/pathname of next application" deal) with
whatever you want, including a little program to re-load the program selector
from disk.
-- 

 --Dave Lyons, Apple Computer, Inc.          |   DAL Systems
   AppleLink--Apple Edition: DAVE.LYONS      |   P.O. Box 875
   AppleLink--Personal Edition: Dave Lyons   |   Cupertino, CA 95015-0875
   GEnie: D.LYONS2 or DAVE.LYONS         CompuServe: 72177,3233
   Internet/BITNET:  dlyons@apple.com    UUCP:  ...!ames!apple!dlyons

   My opinions are my own, not Apple's.