GNU bug report logs - #9469
buffer-local variables seem to remember previous values

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Package: emacs;

Reported by: Le Wang <l26wang <at> gmail.com>

Date: Sat, 10 Sep 2011 17:12:01 UTC

Severity: normal

Tags: notabug

Done: Lars Magne Ingebrigtsen <larsi <at> gnus.org>

Bug is archived. No further changes may be made.

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From: Johan Bockgård <bojohan <at> gnu.org>
To: Stefan Monnier <monnier <at> iro.umontreal.ca>
Cc: Lars Magne Ingebrigtsen <larsi <at> gnus.org>, Andreas Schwab <schwab <at> linux-m68k.org>, 9469 <at> debbugs.gnu.org, Le Wang <l26wang <at> gmail.com>
Subject: bug#9469: buffer-local variables seem to remember previous values
Date: Tue, 13 Sep 2011 20:02:20 +0200
Stefan Monnier <monnier <at> iro.umontreal.ca> writes:

>> "The special form quote returns its single argument, as written,
>> without evaluating it. This provides a way to include constant symbols
>> and lists"
>
>> Isn't the first sentence misleading?  It does not *always* return a
>> single argument as written.  It does the first time, and memoizes
>> subsequently.  Where is the mention of that?
>
> There is no memoization: the quote does not *construct* the object, it
> just returns it.

I think the "as written" bit is mildly confusing, and nearly falls into
this trap:

    In other languages, an expression is text; it has no other form. In
    Lisp, an expression is primarily a Lisp object and only secondarily
    the text that is the object's read syntax. Often there is no need to
    emphasize this distinction, but you must keep it in the back of your
    mind, or you will occasionally be very confused.

        -- (info "(elisp) Printed Representation")




This bug report was last modified 13 years and 307 days ago.

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