Hi Erik,

Thank your for your response.

If cl-colors depends on this behaviour, it's depending on behaviour the cl spec explicitly named "undefined".

It explains clearly. Actually, I was not sure this was a bug of ABCL or not.

> Of course, if you say this is pretty rare when compared to other implementations, I think we should seriously consider accepting a patch to change the behaviour.

Though it could cause a portability issue, as long as the behaviour isn't defined in the spec,
I'm not willing to change the behaviour of ABCL for now.

I'm gonna change cl-colors instead.

Best,
Eitaro

On Mon, Jan 12, 2015 at 2:58 AM, Erik Huelsmann <ehuels@gmail.com> wrote:
Hi Eitaro,

On Sun, Jan 11, 2015 at 6:30 PM, Eitaro Fukamachi <e.arrows@gmail.com> wrote:
This is a reproducible script.

----
(defpackage unexport-test
  (:export :a))

(eval-when (:compile-toplevel :load-toplevel :execute)
  (when (find-package :unexport-test)
    (do-symbols (symbol :unexport-test)
      (unexport symbol :unexport-test))))

(defpackage unexport-test
  (:export :a))

(prin1 (nth-value 1 (intern (string :a) :unexport-test)))


If cl-colors depends on this behaviour, it's depending on behaviour the cl spec explicitly named "undefined". From the spec:

If the new definition is at variance with the current state of that package, the consequences are undefined; an implementation might choose to modify the existing package to reflect the new definition. (see http://www.ai.mit.edu/projects/iiip/doc/CommonLISP/HyperSpec/Body/mac_defpackage.html, third sentence in the Description section)

the important bit is "an implementation might choose to modify"; ABCL currently is an implementation that doesn't modify. Essentially this means you can - in ABCL's current implementation - just leave out the second DEFPACKAGE form...

Of course, if you say this is pretty rare when compared to other implementations, I think we should seriously consider accepting a patch to change the behaviour. Do you know what the *exact* behaviours of SBCL and CCL are? Maybe it's not too hard to implement one of the two. Patch submission always very much welcome as well, of course!


Regards,


--
Bye,

Erik.

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