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| author | Lars Ingebrigtsen <larsi@gnus.org> | 2022-04-26 15:32:45 +0200 |
|---|---|---|
| committer | Lars Ingebrigtsen <larsi@gnus.org> | 2022-04-26 15:34:26 +0200 |
| commit | 756b7cf5d9a817503437b3e8a9e8d912b7ee6c75 (patch) | |
| tree | e39078ffa303d5e1b51ba9e9868b0826fb5ddcaf /lisp/emacs-lisp | |
| parent | 0936bfcd77a671b8dce4ebcdc3e916622d68a865 (diff) | |
| download | emacs-756b7cf5d9a817503437b3e8a9e8d912b7ee6c75.tar.gz emacs-756b7cf5d9a817503437b3e8a9e8d912b7ee6c75.tar.bz2 emacs-756b7cf5d9a817503437b3e8a9e8d912b7ee6c75.zip | |
Mention caveats in the map-delete doc string
* lisp/emacs-lisp/map.el (map-delete): Mention how this has to be
used for lists (bug#25929).
Diffstat (limited to 'lisp/emacs-lisp')
| -rw-r--r-- | lisp/emacs-lisp/map.el | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/lisp/emacs-lisp/map.el b/lisp/emacs-lisp/map.el index c53f253f87f..8c67d7c7a25 100644 --- a/lisp/emacs-lisp/map.el +++ b/lisp/emacs-lisp/map.el @@ -175,7 +175,17 @@ MAP can be an alist, plist, hash-table, or array." (cl-defgeneric map-delete (map key) "Delete KEY in-place from MAP and return MAP. -Keys not present in MAP are ignored.") +Keys not present in MAP are ignored. + +Note that if MAP is a list (either alist or plist), and you're +deleting the final element in the list, the list isn't actually +destructively modified (but the return value will reflect the +deletion). So if you're using this method on a list, you have to +say + + (setq map (map-delete map key)) + +for this to work reliably.") (cl-defmethod map-delete ((map list) key) ;; FIXME: Signal map-not-inplace i.s.o returning a different list? |