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RE: delete-windows-on
From: |
Stephen J. Turnbull |
Subject: |
RE: delete-windows-on |
Date: |
Sat, 03 Oct 2009 03:27:26 +0900 |
Drew Adams writes:
> Why should it be an error? We have ways to check whether an object
> is a buffer - code can always do that.
No. Code *must* *check*. So although signaling the result of the
check is in principal optional, there's no cost to signal an error if
the check fails.
> Why do that here also (in effect)?
Errors should never pass silently.
Unless explicitly silenced.
Among other things, deleting windows on a buffer is a relatively safe
time to signal an error; you're not likely to be screwing anything up
by doing that, the user deals with an annoying beep and it's over.
> To me, it makes sense to treat 42 here the same way we treated nil
> in Emacs 21-22: a no-op. I'd sooner see both (a) a no-op here and
> (b) a return value that indicates what happened.
Status values suck. Programmers do not check them; that is one of the
few things you can truly rely on in software engineering. Checking
them explicitly is indeed a PITA, and inefficient in Emacs Lisp
(requires a function call).
As for no-ops, I don't understand why you want GINO (garbage in, no
output).
> It seems that that is the case here: nil is always returned. I have
> no problem with our documenting that. But it might be even better
> to return some useful info.
Status values are not useful. Neither are the deleted windows, I
guess (don't know about the Emacs implementation, but in XEmacs
deleted windows are quarantined because their attributes are not
reliable -- they don't get updated at all). What useful info do you
suggest (I'd like tomorrow's price of Oracle stock, preferably before
noon today, now *that* would be useful :-)?
- delete-windows-on, Drew Adams, 2009/10/02
- Re: delete-windows-on, Juanma Barranquero, 2009/10/02
- RE: delete-windows-on, Drew Adams, 2009/10/02
- Re: delete-windows-on, Juanma Barranquero, 2009/10/02
- Re: delete-windows-on, martin rudalics, 2009/10/02
- RE: delete-windows-on, Drew Adams, 2009/10/02
- RE: delete-windows-on, Drew Adams, 2009/10/02
- RE: delete-windows-on, Stephen J. Turnbull, 2009/10/03
- RE: delete-windows-on, Drew Adams, 2009/10/02
- RE: delete-windows-on,
Stephen J. Turnbull <=
Re: delete-windows-on, martin rudalics, 2009/10/02