GNU bug report logs - #75170
add-to-alist: new function

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From: "Alfred M. Szmidt" <ams <at> gnu.org>
To: Robert Pluim <rpluim <at> gmail.com>
Cc: winkler <at> gnu.org, monnier <at> gnu.org, 75170 <at> debbugs.gnu.org, stefankangas <at> gmail.com, eliz <at> gnu.org, acorallo <at> gnu.org
Subject: bug#75170: add-to-alist: new function
Date: Tue, 21 Jan 2025 08:09:29 -0500

   >>>>> On Tue, 21 Jan 2025 05:33:48 -0500, "Alfred M. Szmidt" <ams <at> gnu.org> said:

       Alfred>    "Alfred M. Szmidt" <ams <at> gnu.org> writes:

       >> map-put! does not work well with alists that are not 'proper':
       >> 
       ELISP> (setq x (list 1 '(2 . 3)))
       >> (1 (2 . 3))
       >> 
       >> Why should it work on alists at all?  map-put! assumes a map (where is
       >> this structure documented? I did not see anything in the Elisp
       >> manual), not an alist.  Invalid alists will also not work on functions
       >> that assume alists.

       Alfred>    According to M-x describe-package RET map RET:

       Alfred>    map.el provides generic map-manipulation functions that work on
       Alfred>    alists, plists, hash-tables, and arrays.  All functions are
       Alfred>    prefixed with "map-".

       Alfred> That seems like it cannot possibly work (or very complicated).  How do
       Alfred> you differetnate between a plist and alist?  Order in an alist is
       Alfred> important, but not in a plist.  Their syntax is exactly the same, how
       Alfred> can a insertion function work correctly for that?

   map.el assumes that a list that starts with an atom is a plist, and
   any other list is an alist. 


That is just wrong.

   alist-get and assoc obviously disagree.

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