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bug#7083: Why is `copy-tree's symbol-plist carrying side-effect-free err
From: |
MON KEY |
Subject: |
bug#7083: Why is `copy-tree's symbol-plist carrying side-effect-free error-free? |
Date: |
Thu, 23 Sep 2010 01:23:44 -0400 |
On Wed, Sep 22, 2010 at 5:35 PM, Andreas Schwab <schwab@linux-m68k.org> wrote:
> MON KEY <monkey@sandpframing.com> writes:
>
>> It (potentially) `nconc's `nreverse's and `aset's the TREE arg recursively.
>
> Only the copy.
>
Only for the copy of a list.
Why has this bug been marked done?
When copy-tree copies vectors they share structure.
(let ((orig '((a b) (c d) (e f) (g h)))
new-cp)
(setq new-cp (copy-tree orig))
(equal (elt
(prog1 orig
(setf (car new-cp) "bubba")) 0)
'(a b)))
;=> t
(let ((orig [[a b] [c d] [e f] [g h]])
new-cp)
(setq new-cp (copy-tree orig))
(string-equal (aref (prog1 orig
(aset new-cp 0 "bubba"))
0)
"bubba"))
;=> t
Shouldn't idx 0 of the orig tree still be [a b]?
If not, it should be documented that when copy-tree copies vectors the
"copy" will share structure just as with `copy-sequence'.
Regardless, simply marking the bug report as done with only a terse 3
word reply is obnoxious and not the least bit helpful for anyone else
referencing this report in the future, esp. as there does appear to be
a bug.
> Andreas.
--
/s_P\