scratch/sqlite 9553494 1/4: Use a less hacky value for the unbound value

[Lars Ingebrigtsen]

branch: scratch/sqlite
commit 95534948d70daaf3e5abf63273b08c52eb3d7f0e
Author: Lars Ingebrigtsen <larsi@gnus.org>
Commit: Lars Ingebrigtsen <larsi@gnus.org>

    Use a less hacky value for the unbound value
---
 lisp/emacs-lisp/multisession.el | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/lisp/emacs-lisp/multisession.el b/lisp/emacs-lisp/multisession.el
index a15f40c..7eda012 100644
--- a/lisp/emacs-lisp/multisession.el
+++ b/lisp/emacs-lisp/multisession.el
@@ -57,6 +57,8 @@ DOC should be a doc string, and ARGS are keywords as 
applicable to
                         ,@args)
      ,@(list doc)))
 
+(defconst multisession--unbound (make-symbol "unbound"))
+
 (cl-defstruct (multisession
                (:constructor nil)
                (:constructor multisession--create)
@@ -66,8 +68,7 @@ DOC should be a doc string, and ARGS are keywords as 
applicable to
   (initial-value nil)
   package
   (synchronized nil)
-  ;; We need an "impossible" value for the unbound case.
-  (cached-value (make-marker))
+  (cached-value multisession--unbound)
   (cached-sequence 0))
 
 (cl-defun make-multisession (&key key initial-value package synchronized)
@@ -88,7 +89,7 @@ DOC should be a doc string, and ARGS are keywords as 
applicable to
   (if (null user-init-file)
       ;; If we don't have storage, then just return the value from the
       ;; object.
-      (if (markerp (multisession--cached-value object))
+      (if (eq (multisession--cached-value object) multisession--unbound)
           (multisession--initial-value object)
         (multisession--cached-value object))
     ;; We have storage, so we update from storage.
@@ -144,7 +145,7 @@ DOC should be a doc string, and ARGS are keywords as 
applicable to
                   (symbol-name (multisession--key object)))))
     (cond
      ;; We have no value yet; check the database.
-     ((markerp (multisession--cached-value object))
+     ((eq (multisession--cached-value object) multisession--unbound)
       (let ((stored
              (car
               (sqlite-select
@@ -253,7 +254,7 @@ DOC should be a doc string, and ARGS are keywords as 
applicable to
   (let ((file (multisession--object-file-name object)))
     (cond
      ;; We have no value yet; see whether it's stored.
-     ((markerp (multisession--cached-value object))
+     ((eq (multisession--cached-value object) multisession--unbound)
       (if (file-exists-p file)
           (multisession--update-file-value file object)
         ;; Nope; return the initial value.