Re: Replacement for `aput' from obsolete assoc.el?

[Stephen J. Turnbull]

Thien-Thi Nguyen writes:
 > () Andreas Schwab <address@hidden>
 > () Sat, 09 Jun 2012 11:46:38 +0200
 > 
 >    "Stephen J. Turnbull" <address@hidden> writes:
 > 
 >    > `plist-put' and `plist-get' are actually defined in C, but this shows
 >    > how `memq' works well with plists:
 >    >
 >    > (defun plist-get (plist key)
 >    >   (cadr (memq key plist)))
 > 
 >    That fails if key is eq to a value.
 > 
 > That is, a value closer to the plist head than the desired key.
 > (If after, no worries.)

True, but of course it's a bug.  My bad.

In practice the idiom `(memq key plist)' is sometimes useful where
keys are guaranteed to be disjoint from values.  I shouldn't have
tried to overgeneralize.