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Re: problem with text properties whose names aren't symbols
From: |
Andreas Schwab |
Subject: |
Re: problem with text properties whose names aren't symbols |
Date: |
Mon, 12 Dec 2005 12:04:12 +0100 |
User-agent: |
Gnus/5.110003 (No Gnus v0.3) Emacs/22.0.50 (gnu/linux) |
Joe Corneli <jcorneli@planetmath.org> writes:
>>From the elisp manual (node: Text Properties):
>
> Each property has a name and a value. Both of these
> can be any Lisp object, but the name is normally a symbol.
>
> Well, it seems that when the Lisp object is not a symbol,
> there is a problem. This is illustrated by evaluating
> the following form interactively:
>
> (progn
> (put-text-property (point) (1+ (point))
> '(example name)
> t)
> (put-text-property (point) (1+ (point))
> '(example name)
> nil)
> (text-properties-at (point)))
This is not a bug, because '(example name) and '(example name) are
distinct objects:
ELISP> (eq '(example name) '(example name))
nil
Try this instead:
(let ((name '(example name)))
(put-text-property (point) (1+ (point)) name t)
(put-text-property (point) (1+ (point)) name nil)
(text-properties-at (point)))
Andreas.
--
Andreas Schwab, SuSE Labs, schwab@suse.de
SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
PGP key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
"And now for something completely different."