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bug#38173: describe-variable: Also tell user *where* variable was change
From: |
Phil Sainty |
Subject: |
bug#38173: describe-variable: Also tell user *where* variable was changed |
Date: |
Thu, 14 Nov 2019 11:56:39 +1300 |
User-agent: |
Orcon Webmail |
On 2019-11-14 04:06, 積丹尼 Dan Jacobson wrote:
PS> It still might not have the effect you wanted, though -- it's
PS> possible to change the apparent / user-facing value of some
variables
PS> without changing the *actual* value of the variable at all. This
is
PS> because of the internal structure of lists in lisp...
Sounds like a security / coverup risk. Maybe with the expensive
global-variable-tracking turned on, describe-variable could double
check
for such tampering upon looking up a variable.
It's not "tampering". It's just the fundamental nature of lists in lisp
(all dialects of lisp, AFAIK). You're only seeing it as a concern in
the
context of a feature which doesn't exist.
It would, I think, be *dramatically* (perhaps prohibitively) more
expensive
to perform that kind of checking. This could no longer be done by the
variable-watcher mechanism. In principle, every time ANY lisp object
was
modified at all, Emacs would need to check to see whether the object
(pre-
modification) was a value -- or a nested sub-component, to any arbitrary
depth, of a value -- of ANY variable in the system, so that it could
register
that the change affected the user-facing value of that variable.
-Phil
- bug#38173: describe-variable: Also tell user *where* variable was changed, 積丹尼 Dan Jacobson, 2019/11/11
- bug#38173: describe-variable: Also tell user *where* variable was changed, Katsumi Yamaoka, 2019/11/11
- bug#38173: describe-variable: Also tell user *where* variable was changed, 積丹尼 Dan Jacobson, 2019/11/11
- bug#38173: describe-variable: Also tell user *where* variable was changed, Phil Sainty, 2019/11/12
- bug#38173: describe-variable: Also tell user *where* variable was changed, 積丹尼 Dan Jacobson, 2019/11/12
- bug#38173: describe-variable: Also tell user *where* variable was changed, Phil Sainty, 2019/11/13
- bug#38173: describe-variable: Also tell user *where* variable was changed, 積丹尼 Dan Jacobson, 2019/11/13
- bug#38173: describe-variable: Also tell user *where* variable was changed,
Phil Sainty <=
- bug#38173: describe-variable: Also tell user *where* variable was changed, Lars Ingebrigtsen, 2019/11/14