Re: Issue GC-MESSAGES (Version 1)

[Masinter.pa@Xerox.COM]

>Date: Thu, 23 Apr 87 23:31 EDT
>From: David A. Moon <Moon@STONY-BROOK.SCRC.Symbolics.COM>

>This seems a little short-sighted.  GC messages aren't necessarily the
>only unsolicited messages.  In the example application you gave, there
>is no reason to treat GC messages differently from other messages.

>Also, a simple on/off switch may be a bit too simple.  Not all systems
>have windows, but for the ones that do a three-state switch could be
>defined in an implementation-independent way: (1) turn the messages
off,
>(2) put them in the typescript, (3) make them visible to the user in a
>way that doesn't interfere with the typescript.  Even some
>teletype-oriented systems are able to implement option 3.

>In some systems it may not be possible to implement this with a
variable,
>since changing the state of the switch may have to communicate with an
>operating system written in some horrible language.  The safest thing
would
>be a macro, whose expansion is system-dependent, and within the dynamic
>extent of the macro's body unsolicited messages are controlled.

>I'm not very optimistic about the possibility of standardizing on this
kind
>of environmental issue, but perhaps some very simple facility to
prevent
>messing up of the screen can be agreed on.

I agree that the GC-MESSAGE issue should be somehow merged with a good
way of dealing with all unsolicited messages.

I can think of other alternatives to the solution proposed by David ("a
macro, whose expansion is system-dependent, and within the dynamic
extent of the macro's body unsolicited messages are controlled.").

I'd like to see the "current practice" section expanded. I know that
Xerox Common Lisp has no unsolicited GC messages, don't know about
Lucid, Gold Hill, Franz, etc.

Kent, since you apparently know what these other systems do ("Other
systems provide ways of enabling or disabling the messages, or
customizing the message which is typed out." perhaps you could
elaborate.)