procyberian/emacs
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

* lisp/emacs-lisp/cl-preloaded.el (cl-struct-define): Fix duplication

Browse source 
which resulted in incomplete list of parents in one copy of the
cl-structure-class class.
This commit is contained in:
Stefan Monnier 2017-02-21 13:48:30 -05:00
parent 20dda6be76
commit e785c74d3a
1 changed files with 14 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

15
lisp/emacs-lisp/cl-preloaded.el
View file

@ -151,7 +151,20 @@
(add-to-list 'current-load-list `(define-type . ,name))
(cl--struct-register-child parent-class tag)
(unless (eq named t)
(eval `(defconst ,tag ',class) t)
;; We used to use `defconst' instead of `set' but that
;; has a side-effect of purecopying during the dump, so that the
;; class object stored in the tag ends up being a *copy* of the
;; one stored in the `cl--class' property! We could have fixed
;; this needless duplication by using the purecopied object, but
;; that then breaks down a bit later when we modify the
;; cl-structure-class class object to close the recursion
;; between cl-structure-object and cl-structure-class (because
;; modifying purecopied objects is not allowed. Since this is
;; done during dumping, we could relax this rule and allow the
;; modification, but it's cumbersome).
;; So in the end, it's easier to just avoid the duplication by
;; avoiding the use of the purespace here.
(set tag class)
;; In the cl-generic support, we need to be able to check
;; if a vector is a cl-struct object, without knowing its particular type.
;; So we use the (otherwise) unused function slots of the tag symbol