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Interpretation of IMPORT
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Zach Beane
Dec 21, 2011, 12:49:55 PM12/21/11
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What do you get when you call the following function?
(defun apparently-uninterned-import ()
(let ((foo (make-package "FOO" :use nil))
(bar (make-package "BAR" :use nil)))
(with-output-to-string (*standard-output*)
(let ((symbol (intern "A" foo)))
(write symbol)
(write-char #\Space)
(import symbol bar)
(unintern symbol foo)
(write symbol)
(write-char #\Space)
(when (eql (nth-value 1 (find-symbol "A" bar))
:internal)
(write 'present)
(write-char #\Space))
(import symbol bar)
(write symbol))
(delete-package foo)
(delete-package bar))))
From some CLs I get this:
"FOO::A #:A PRESENT BAR::A"
For others I get this:
"FOO::A #:A PRESENT #:A"
Which one is right?
Zach
(defun apparently-uninterned-import ()
(let ((foo (make-package "FOO" :use nil))
(bar (make-package "BAR" :use nil)))
(with-output-to-string (*standard-output*)
(let ((symbol (intern "A" foo)))
(write symbol)
(write-char #\Space)
(import symbol bar)
(unintern symbol foo)
(write symbol)
(write-char #\Space)
(when (eql (nth-value 1 (find-symbol "A" bar))
:internal)
(write 'present)
(write-char #\Space))
(import symbol bar)
(write symbol))
(delete-package foo)
(delete-package bar))))
From some CLs I get this:
"FOO::A #:A PRESENT BAR::A"
For others I get this:
"FOO::A #:A PRESENT #:A"
Which one is right?
Zach
Pascal J. Bourguignon
Dec 21, 2011, 1:16:34 PM12/21/11
to
--
__Pascal Bourguignon__ http://www.informatimago.com/
A bad day in () is better than a good day in {}.
Zach Beane
Dec 21, 2011, 1:40:56 PM12/21/11
to
"Pascal J. Bourguignon" <p...@informatimago.com> writes:
>> From some CLs I get this:
>>
>> "FOO::A #:A PRESENT BAR::A"
>>
>> For others I get this:
>>
>> "FOO::A #:A PRESENT #:A"
>>
>> Which one is right?
>
> IIRC, both are right.
Why?
>> From some CLs I get this:
>>
>> "FOO::A #:A PRESENT BAR::A"
>>
>> For others I get this:
>>
>> "FOO::A #:A PRESENT #:A"
>>
>> Which one is right?
>
> IIRC, both are right.
Zach
Kaz Kylheku
Dec 21, 2011, 3:02:22 PM12/21/11
to
On 2011-12-21, Zach Beane <xa...@xach.com> wrote:
> What do you get when you call the following function?
>
> (defun apparently-uninterned-import ()
Ron Garret emerges from the machine and whacks you over the head
> What do you get when you call the following function?
>
> (defun apparently-uninterned-import ()
with a printed copy of the HyperSpec.
Zach Beane
Dec 21, 2011, 3:10:15 PM12/21/11
to
Zach
Barry Margolin
Dec 21, 2011, 3:44:31 PM12/21/11
to
In article <87r4zxr...@kuiper.lan.informatimago.com>,
I disagree, the first is right.
UNINTERN says "If _package_ is the home package for _symbol_, _symbol_
is made to have no home package." So after (unintern symbol foo), A has
no home package.
IMPORT says "If any symbol to be imported has no home package (i.e.,
(symbol-package symbol) => nil), import sets the home package of the
symbol to _package_." So (import symbol bar) is supposed to set the home
package to BAR.
CLTL1 didn't specify the latter behavior, but it was clarified in ANSI
CL.
--
Barry Margolin, bar...@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***
UNINTERN says "If _package_ is the home package for _symbol_, _symbol_
is made to have no home package." So after (unintern symbol foo), A has
no home package.
IMPORT says "If any symbol to be imported has no home package (i.e.,
(symbol-package symbol) => nil), import sets the home package of the
symbol to _package_." So (import symbol bar) is supposed to set the home
package to BAR.
CLTL1 didn't specify the latter behavior, but it was clarified in ANSI
CL.
--
Barry Margolin, bar...@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***
Zach Beane
Dec 21, 2011, 3:47:59 PM12/21/11
to
Barry Margolin <bar...@alum.mit.edu> writes:
>> > From some CLs I get this:
>> >
>> > "FOO::A #:A PRESENT BAR::A"
>> >
>> > For others I get this:
>> >
>> > "FOO::A #:A PRESENT #:A"
>> >
>> > Which one is right?
>>
>> IIRC, both are right.
>
> I disagree, the first is right.
>
> UNINTERN says "If _package_ is the home package for _symbol_, _symbol_
> is made to have no home package." So after (unintern symbol foo), A has
> no home package.
>
> IMPORT says "If any symbol to be imported has no home package (i.e.,
> (symbol-package symbol) => nil), import sets the home package of the
> symbol to _package_." So (import symbol bar) is supposed to set the home
> package to BAR.
IMPORT also says "If the symbol is already present in the importing
>> > From some CLs I get this:
>> >
>> > "FOO::A #:A PRESENT BAR::A"
>> >
>> > For others I get this:
>> >
>> > "FOO::A #:A PRESENT #:A"
>> >
>> > Which one is right?
>>
>> IIRC, both are right.
>
> I disagree, the first is right.
>
> UNINTERN says "If _package_ is the home package for _symbol_, _symbol_
> is made to have no home package." So after (unintern symbol foo), A has
> no home package.
>
> IMPORT says "If any symbol to be imported has no home package (i.e.,
> (symbol-package symbol) => nil), import sets the home package of the
> symbol to _package_." So (import symbol bar) is supposed to set the home
> package to BAR.
package, import has no effect." The symbol is already present in this
scenario. Is changing the home package of the symbol an effect?
Zach
Barry Margolin
Dec 21, 2011, 3:52:28 PM12/21/11
to
In article <87d3bhw...@hangup.portland.xach.com>,
Ahh, I missed the earlier import. That is indeed an ambiguity.
Kaz Kylheku
Dec 21, 2011, 4:09:43 PM12/21/11
to
On 2011-12-21, Zach Beane <xa...@xach.com> wrote:
> Kaz Kylheku <k...@kylheku.com> writes:
>
>> On 2011-12-21, Zach Beane <xa...@xach.com> wrote:
>>> What do you get when you call the following function?
>>>
>>> (defun apparently-uninterned-import ()
>>
>> Ron Garret emerges from the machine and whacks you over the head
>> with a printed copy of the HyperSpec.
>
> Morely likely a copy of CLtL2.
Yeah! You know, I was going to write CLtL2!
> Kaz Kylheku <k...@kylheku.com> writes:
>
>> On 2011-12-21, Zach Beane <xa...@xach.com> wrote:
>>> What do you get when you call the following function?
>>>
>>> (defun apparently-uninterned-import ()
>>
>> Ron Garret emerges from the machine and whacks you over the head
>> with a printed copy of the HyperSpec.
>
> Morely likely a copy of CLtL2.
Mattias Nilsson
Dec 22, 2011, 7:03:59 AM12/22/11
to
On Dec 21, 9:47 pm, Zach Beane <x...@xach.com> wrote:
> Barry Margolin <bar...@alum.mit.edu> writes:
> >> > From some CLs I get this:
>
> >> > "FOO::A #:A PRESENT BAR::A"
>
> >> > For others I get this:
>
> >> > "FOO::A #:A PRESENT #:A"
>
> >> > Which one is right?
>
> >> IIRC, both are right.
>
> > I disagree, the first is right.
>
> > UNINTERN says "If _package_ is the home package for _symbol_, _symbol_
> > is made to have no home package." So after (unintern symbol foo), A has
> > no home package.
>
> > IMPORT says "If any symbol to be imported has no home package (i.e.,
> > (symbol-package symbol) => nil), import sets the home package of the
> > symbol to _package_."
I think the key part here is: "to be imported"; which is not the case
> Barry Margolin <bar...@alum.mit.edu> writes:
> >> > From some CLs I get this:
>
> >> > "FOO::A #:A PRESENT BAR::A"
>
> >> > For others I get this:
>
> >> > "FOO::A #:A PRESENT #:A"
>
> >> > Which one is right?
>
> >> IIRC, both are right.
>
> > I disagree, the first is right.
>
> > UNINTERN says "If _package_ is the home package for _symbol_, _symbol_
> > is made to have no home package." So after (unintern symbol foo), A has
> > no home package.
>
> > IMPORT says "If any symbol to be imported has no home package (i.e.,
> > (symbol-package symbol) => nil), import sets the home package of the
> > symbol to _package_."
in
your code because of the following:
> IMPORT also says "If the symbol is already present in the importing
> package, import has no effect."
Mattias
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