Re: [Sbcl-devel] Deprecation notice

[David L. <da...@li...>]

Hi,

Quoting Zach Beane (xa...@xa...):
> I get this:
> 
>   ; caught STYLE-WARNING:
>   ;   SB-EXT:QUIT has been deprecated as of SBCL 1.0.56.55. Use
>   ;   SB-EXT:EXIT or SB-THREAD:ABORT-THREAD instead.
> 
> Although it's not *too* difficult to do it manually, it might be nicer
> to provide a date rather than a version number.

I would like to follow up on this (by now rather old) discussion with a
(possibly) controversial opinion:

Can we please un-deprecate QUIT?

My rationale is as follows:

  - QUIT has existed at least since CMUCL times -- it is inconvenient
    for users to switch away from it.

  - It is not hurtful to have both EXIT and QUIT.  While I wouldn't
    personally have advocated adding a second such function, now that
    they exist, it is easiest to keep them both.  In fact, it could make
    it easier for users to switch between CMUCL/SBCL and other Lisps
    using the name EXIT, in the sense of a compatibility function.

  - If we do not keep them both, we should retain the older name, not
    a newer one.

  - As far as I understand (please correct me if I'm wrong), the
    reasoning against QUIT is that, at some point during SBCL's
    development, its (originally per-process) semantics got
    re-interpreted to do certain things with regard to threads, which
    ultimately turned out to be problematic.  So what is deprecated is
    not the original per-process meaning, but rather the incompatible
    per-thread meaning affecting callers in multithreaded scenarios.

    Hence, if we change QUIT to work like EXIT, we're actually restoring
    a meaning rather close to what QUIT used to do in SBCL and CMUCL in
    the past.

  - And now that the old semantics have been deprecated for a few
    releases, any users actually depending on the per-thread usage have
    been warned, so it's not too hurtful to them if QUIT reverts to a
    per-process meaning.

Specifically, my suggestion is to leave QUIT's keyword arguments as-is,
but remove the special case of (not (main-thread-p)) from its body.

d.