From: Alan Mackenzie <acm@muc.de>
To: Drew Adams <drew.adams@oracle.com>
Cc: emacs-devel@gnu.org
Subject: Re: setq's with missing final arguments.
Date: Sun, 22 Nov 2015 23:08:15 +0000 [thread overview]
Message-ID: <20151122230815.GE2332@acm.fritz.box> (raw)
In-Reply-To: <065d0399-7e58-465d-b57f-5ebe91695e59@default>
Hello, Drew.
On Sun, Nov 22, 2015 at 07:52:48AM -0800, Drew Adams wrote:
> > (defun bad-setq ()
> > "Doc string"
> > (setq foo 5
> > bar))
> > In the setq, there is a missing argument after "bar". At the moment,
> > the byte compiler just generates code to assign nil to bar, without
> > giving any warning. IMAO, this is Very Bad.
> > I propose to insert code into the byte compiler to detect and warn of
> > this scenario:
> It's not just the byte-compiler. This is the (erroneous, IMO)
> behavior of `setq', whether interpreted or byte-compiled:
> (setq bar) ; bar := nil
> (setq bar) should raise an error. The doc says that `setq'
> requires an even number of args. Same thing in other Lisps
> (e.g., Common Lisp).
Just before midnight, I think I would agree with you. With the help of
the above warning facility, I have located all (six) occurrences of odd
numbers of arguments to a `setq' in our sources. One was a quite nasty
error, one is in .../lisp/obsolete, the other four are "coding style"
thingies. It would take at least five minutes to fix them all.
I now think we should make any setq with a missing value throw an error,
whether in interpreted code or in the byte compiler. And I think we
should do it for Emacs 25.1.
John?
--
Alan Mackenzie (Nuremberg, Germany).
next prev parent reply other threads:[~2015-11-22 23:08 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-22 12:26 setq's with missing final arguments Alan Mackenzie
2015-11-22 12:31 ` David Kastrup
2015-11-22 12:35 ` Oleh Krehel
2015-11-22 12:44 ` Teemu Likonen
2015-11-22 15:53 ` multi-assignment setq [was: setq's with missing final arguments.] Drew Adams
2015-11-23 7:58 ` Oleh Krehel
2015-11-23 15:02 ` Drew Adams
2015-11-22 12:52 ` setq's with missing final arguments Andreas Schwab
2015-11-22 13:03 ` Artur Malabarba
2015-11-22 13:08 ` David Kastrup
2015-11-22 13:11 ` Andreas Schwab
2015-11-22 13:23 ` David Kastrup
2015-11-22 13:34 ` Andreas Schwab
2015-11-22 14:10 ` Alan Mackenzie
2015-11-22 15:44 ` Eli Zaretskii
2015-11-22 19:44 ` Alan Mackenzie
2015-11-23 1:36 ` Drew Adams
2015-11-22 15:42 ` Johan Bockgård
2015-11-22 16:04 ` Drew Adams
2015-11-22 15:52 ` Drew Adams
2015-11-22 23:08 ` Alan Mackenzie [this message]
2015-11-22 23:20 ` John Wiegley
2015-11-23 1:54 ` Drew Adams
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