* lisp/frameset.el: Add new predicate values for frameset-restore args.

  (frameset-live-filter-alist, frameset-persistent-filter-alist):
  New variables.
  (frameset-filter-alist): Use them.  Add autoload cookie.
  (frameset-filter-tty-to-GUI): Move from desktop.el and rename.
  (frameset--set-id, frameset--reuse-frame): Rename `frame-id' to
  `frameset--id' (it's supposed to be internal to frameset.el).
  (frameset--process-minibuffer-frames): Ditto.  Doc fix.
  (frameset--initial-params): New function.
  (frameset--get-frame): Use it.  Doc fix.
  (frameset--move-onscreen): Accept new PRED value for FORCE-ONSCREEN.
  Accept :all, not 'all.
  (frameset-restore): Add new predicate values for FORCE-ONSCREEN and
  FORCE-DISPLAY.  Use :keywords for constant arguments to avoid collision
  with fbound symbols.  Fix frame id matching, and remove matching ids if
  the frame being restored is deleted.  Obey :delete.

* lisp/desktop.el (desktop-restore-forces-onscreen)
  (desktop-restore-reuses-frames): Document :keyword constant values.
  (desktop-filter-parameters-alist): Remove, now identical to
  frameset-filter-alist.
  (desktop--filter-tty*): Remove, moved to frameset.el.
  (desktop-save-frameset, desktop-restore-frameset):
  Do not pass :filters argument.

3 files changed, 202 insertions, 142 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 66bf7422b0d..de1da73bbb1 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,29 @@
+2013-08-04  Juanma Barranquero  <lekktu@gmail.com>
+
+        * desktop.el (desktop-restore-forces-onscreen)
+        (desktop-restore-reuses-frames): Document :keyword constant values.
+        (desktop-filter-parameters-alist): Remove, now identical to
+        frameset-filter-alist.
+        (desktop--filter-tty*): Remove, moved to frameset.el.
+        (desktop-save-frameset, desktop-restore-frameset):
+        Do not pass :filters argument.
+
+        * frameset.el (frameset-live-filter-alist)
+        (frameset-persistent-filter-alist): New variables.
+        (frameset-filter-alist): Use them.  Add autoload cookie.
+        (frameset-filter-tty-to-GUI): Move from desktop.el and rename.
+        (frameset--set-id, frameset--reuse-frame): Rename `frame-id' to
+        `frameset--id' (it's supposed to be internal to frameset.el).
+        (frameset--process-minibuffer-frames): Ditto.  Doc fix.
+        (frameset--initial-params): New function.
+        (frameset--get-frame): Use it.  Doc fix.
+        (frameset--move-onscreen): Accept new PRED value for FORCE-ONSCREEN.
+        Accept :all, not 'all.
+        (frameset-restore): Add new predicate values for FORCE-ONSCREEN and
+        FORCE-DISPLAY.  Use :keywords for constant arguments to avoid collision
+        with fbound symbols.  Fix frame id matching, and remove matching ids if
+        the frame being restored is deleted.  Obey :delete.
+
 2013-08-04  Stefan Monnier  <monnier@iro.umontreal.ca>
 
         * subr.el (macrop): New function.
diff --git a/lisp/desktop.el b/lisp/desktop.el
index 778c37484e1..ab78663c3d0 100644
--- a/lisp/desktop.el
+++ b/lisp/desktop.el
@@ -390,12 +390,12 @@ If `delete', frames on other displays are deleted instead of restored."
 
 (defcustom desktop-restore-forces-onscreen t
   "If t, offscreen frames are restored onscreen instead.
-If `all', frames that are partially offscreen are also forced onscren.
+If `:all', frames that are partially offscreen are also forced onscren.
 NOTE: Checking of frame boundaries is only approximate and can fail
 to reliably detect frames whose onscreen/offscreen state depends on a
 few pixels, especially near the right / bottom borders of the screen."
   :type '(choice (const :tag "Only fully offscreen frames" t)
-                 (const :tag "Also partially offscreen frames" 'all)
+                 (const :tag "Also partially offscreen frames" :all)
                  (const :tag "Do not force frames onscreen" nil))
   :group 'desktop
   :version "24.4")
@@ -403,10 +403,10 @@ few pixels, especially near the right / bottom borders of the screen."
 (defcustom desktop-restore-reuses-frames t
   "If t, restoring frames reuses existing frames.
 If nil, existing frames are deleted.
-If `keep', existing frames are kept and not reused."
+If `:keep', existing frames are kept and not reused."
   :type '(choice (const :tag "Reuse existing frames" t)
                  (const :tag "Delete existing frames" nil)
-                 (const :tag "Keep existing frames" 'keep))
+                 (const :tag "Keep existing frames" :keep))
   :group 'desktop
   :version "24.4")
 
@@ -900,25 +900,6 @@ DIRNAME must be the directory in which the desktop file will be saved."
 
 
 ;; ----------------------------------------------------------------------------
-(defvar desktop-filter-parameters-alist
-  (append '((font-backend        . t)
-            (name                . t)
-            (outer-window-id     . t)
-            (parent-id           . t)
-            (tty                 . desktop--filter-tty*)
-            (tty-type            . desktop--filter-tty*)
-            (window-id           . t)
-            (window-system       . t))
-          frameset-filter-alist)
-  "Alist of frame parameters and filtering functions.
-Its format is identical to `frameset-filter-alist' (which see).")
-
-(defun desktop--filter-tty* (_current parameters saving)
-  ;; Remove tty and tty-type parameters when switching
-  ;; to a GUI frame.
-  (or saving
-      (not (frameset-switch-to-gui-p parameters))))
-
 (defun desktop--check-dont-save (frame)
   (not (frame-parameter frame 'desktop-dont-save)))
 
@@ -932,7 +913,6 @@ Frames with a non-nil `desktop-dont-save' parameter are not saved."
              (let ((name (concat user-login-name "@" system-name
                                  (format-time-string " %Y-%m-%d %T"))))
                (frameset-save nil
-                              :filters desktop-filter-parameters-alist
                               :predicate #'desktop--check-dont-save
                               :properties (list :app desktop--app-id
                                                 :name name))))))
@@ -1049,7 +1029,6 @@ This function depends on the value of `desktop-saved-frameset'
 being set (usually, by reading it from the desktop)."
   (when (desktop-restoring-frameset-p)
     (frameset-restore desktop-saved-frameset
-                      :filters desktop-filter-parameters-alist
                       :reuse-frames desktop-restore-reuses-frames
                       :force-display desktop-restore-in-current-display
                       :force-onscreen desktop-restore-forces-onscreen)))
diff --git a/lisp/frameset.el b/lisp/frameset.el
index 2a6a0d2dfb8..b24e4ed9362 100644
--- a/lisp/frameset.el
+++ b/lisp/frameset.el
@@ -46,16 +46,16 @@
 ;;   user-defined serializable data.  Currently defined properties
 ;;   include:
 ;;     :version ID  - Identifies the version of the frameset struct;
-;;                    this is the only property always present and
-;;                    must not be modified.
+;;                    this is the only property always present and
+;;                    must not be modified.
 ;;     :app APPINFO - Freeform.  Can be used by applications and
-;;                    packages to indicate the intended (but by no
-;;                    means exclusive) use of the frameset.  For
-;;                    example, currently desktop.el sets :app to
-;;                    `(desktop . ,desktop-file-version).
+;;                    packages to indicate the intended (but by no
+;;                    means exclusive) use of the frameset.  For
+;;                    example, currently desktop.el sets :app to
+;;                    `(desktop . ,desktop-file-version).
 ;;     :name NAME   - The name of the frameset instance; a string.
 ;;     :desc TEXT   - A description for user consumption (to choose
-;;                    among framesets, etc.); a string.
+;;                    among framesets, etc.); a string.
 ;; - states: an alist of items (FRAME-PARAMETERS . WINDOW-STATE) in
 ;;   no particular order.  Each item represents a frame to be
 ;;   restored.
@@ -98,46 +98,66 @@ Properties other than :version can be set with
 
 ;; Filtering
 
-(defvar frameset-filter-alist
-  '((background-color    . frameset-filter-sanitize-color)
-    (buffer-list         . t)
-    (buffer-predicate    . t)
-    (buried-buffer-list  . t)
-    (font                . frameset-filter-save-parm)
-    (foreground-color    . frameset-filter-sanitize-color)
-    (fullscreen          . frameset-filter-save-parm)
-    (GUI:font            . frameset-filter-restore-parm)
-    (GUI:fullscreen      . frameset-filter-restore-parm)
-    (GUI:height          . frameset-filter-restore-parm)
-    (GUI:width           . frameset-filter-restore-parm)
-    (height              . frameset-filter-save-parm)
-    (left                . frameset-filter-iconified)
-    (minibuffer          . frameset-filter-minibuffer)
-    (top                 . frameset-filter-iconified)
-    (width               . frameset-filter-save-parm))
+;;;###autoload
+(defvar frameset-live-filter-alist
+  '((name            . t)
+    (minibuffer      . frameset-filter-minibuffer)
+    (top             . frameset-filter-iconified))
+  "Minimum set of parameters to filter for live (on-session) framesets.
+See `frameset-filter-alist' for a full description.")
+
+;;;###autoload
+(defvar frameset-persistent-filter-alist
+  (nconc
+   '((background-color   . frameset-filter-sanitize-color)
+     (buffer-list        . t)
+     (buffer-predicate   . t)
+     (buried-buffer-list . t)
+     (font               . frameset-filter-save-parm)
+     (foreground-color   . frameset-filter-sanitize-color)
+     (fullscreen         . frameset-filter-save-parm)
+     (GUI:font           . frameset-filter-restore-parm)
+     (GUI:fullscreen     . frameset-filter-restore-parm)
+     (GUI:height         . frameset-filter-restore-parm)
+     (GUI:width          . frameset-filter-restore-parm)
+     (height             . frameset-filter-save-parm)
+     (left               . frameset-filter-iconified)
+     (outer-window-id    . t)
+     (parent-id          . t)
+     (tty                . frameset-filter-tty-to-GUI)
+     (tty-type           . frameset-filter-tty-to-GUI)
+     (width              . frameset-filter-save-parm)
+     (window-id          . t)
+     (window-system      . t))
+   frameset-live-filter-alist)
+  "Recommended set of parameters to filter for persistent framesets.
+See `frameset-filter-alist' for a full description.")
+
+;;;###autoload
+(defvar frameset-filter-alist frameset-persistent-filter-alist
   "Alist of frame parameters and filtering functions.
 
 Each element is a cons (PARAM . ACTION), where PARAM is a parameter
 name (a symbol identifying a frame parameter), and ACTION can be:
 
- t         The parameter is always removed from the parameter list.
- :save     The parameter is removed when saving the frame.
+ t         The parameter is always removed from the parameter list.
+ :save     The parameter is removed when saving the frame.
  :restore  The parameter is removed when restoring the frame.
- FILTER    A filter function.
+ FILTER    A filter function.
 
 FILTER can be a symbol FILTER-FUN, or a list (FILTER-FUN ARGS...).
 It will be called with four arguments CURRENT, FILTERED, PARAMETERS
 and SAVING, plus any additional ARGS:
 
  CURRENT     A cons (PARAM . VALUE), where PARAM is the one being
-             filtered and VALUE is its current value.
+             filtered and VALUE is its current value.
  FILTERED    The alist of parameters filtered so far.
  PARAMETERS  The complete alist of parameters being filtered,
- SAVING      Non-nil if filtering before saving state, nil otherwise.
+ SAVING      Non-nil if filtering before saving state, nil otherwise.
 
 The FILTER-FUN function must return:
- nil                  CURRENT is removed from the list.
- t                    CURRENT is left as is.
+ nil                  CURRENT is removed from the list.
+ t                    CURRENT is left as is.
  (PARAM' . VALUE')    Replace CURRENT with this.
 
 Frame parameters not on this list are passed intact.")
@@ -156,9 +176,9 @@ Return t if PARAMETERS describes a text-only terminal and
 the target is a graphic display; otherwise return nil.
 Only meaningful when called from a filtering function in
 `frameset-filter-alist'."
-  (and frameset--target-display                     ; we're switching
-       (null (cdr (assq 'display parameters)))      ; from a tty
-       (cdr frameset--target-display)))             ; to a GUI display
+  (and frameset--target-display                   ; we're switching
+       (null (cdr (assq 'display parameters)))    ; from a tty
+       (cdr frameset--target-display)))           ; to a GUI display
 
 (defun frameset-switch-to-tty-p (parameters)
   "True when switching to a text-only terminal.
@@ -167,9 +187,14 @@ the target is a text-only terminal; otherwise return nil.
 Only meaningful when called from a filtering function in
 `frameset-filter-alist'."
   (and frameset--target-display                   ; we're switching
-       (cdr (assq 'display parameters))           ; from a GUI display
+       (cdr (assq 'display parameters))           ; from a GUI display
        (null (cdr frameset--target-display))))    ; to a tty
 
+(defun frameset-filter-tty-to-GUI (_current _filtered parameters saving)
+  "Remove CURRENT when switching from tty to a graphic display."
+  (or saving
+      (not (frameset-switch-to-gui-p parameters))))
+
 (defun frameset-filter-sanitize-color (current _filtered parameters saving)
   "When switching to a GUI frame, remove \"unspecified\" colors.
 Useful as a filter function for tty-specific parameters."
@@ -223,12 +248,6 @@ meaningless in an iconified frame, so the frame is restored in a
 default position."
   (not (and saving (eq (cdr (assq 'visibility parameters)) 'icon))))
 
-(defun frameset-keep-original-display-p (force-display)
-  "True if saved frames' displays should be honored."
-  (cond ((daemonp) t)
-        ((eq system-type 'windows-nt) nil)
-        (t (null force-display))))
-
 (defun frameset-filter-params (parameters filter-alist saving)
   "Filter parameter list PARAMETERS and return a filtered list.
 FILTER-ALIST is an alist of parameter filters, in the format of
@@ -265,18 +284,18 @@ nil while the filtering is done to restore it."
 ;; Saving framesets
 
 (defun frameset--set-id (frame)
-  "Set FRAME's `frame-id' if not yet set.
+  "Set FRAME's `frameset--id' if not yet set.
 Internal use only."
-  (unless (frame-parameter frame 'frame-id)
+  (unless (frame-parameter frame 'frameset--id)
     (set-frame-parameter frame
-                         'frame-id
+                         'frameset--id
                          (mapconcat (lambda (n) (format "%04X" n))
                                     (cl-loop repeat 4 collect (random 65536))
                                     "-"))))
 
 (defun frameset--process-minibuffer-frames (frame-list)
   "Process FRAME-LIST and record minibuffer relationships.
-FRAME-LIST is a list of frames."
+FRAME-LIST is a list of frames.  Internal use only."
   ;; Record frames with their own minibuffer
   (dolist (frame (minibuffer-frame-list))
     (when (memq frame frame-list)
@@ -292,12 +311,12 @@ FRAME-LIST is a list of frames."
     (unless (frame-parameter frame 'frameset--mini)
       (frameset--set-id frame)
       (let* ((mb-frame (window-frame (minibuffer-window frame)))
-             (id (and mb-frame (frame-parameter mb-frame 'frame-id))))
+             (id (and mb-frame (frame-parameter mb-frame 'frameset--id))))
         (if (null id)
             (error "Minibuffer frame %S for %S is excluded" mb-frame frame)
           ;; For minibufferless frames, frameset--mini is a cons
-          ;; (nil . FRAME-ID), where FRAME-ID is the frame-id of
-          ;; the frame containing its minibuffer window.
+          ;; (nil . FRAME-ID), where FRAME-ID is the frameset--id
+          ;; of the frame containing its minibuffer window.
           (set-frame-parameter frame
                                'frameset--mini
                                (cons nil id)))))))
@@ -345,26 +364,32 @@ When forced onscreen, frames wider than the monitor's workarea are converted
 to fullwidth, and frames taller than the workarea are converted to fullheight.
 NOTE: This only works for non-iconified frames.  Internal use only."
   (pcase-let* ((`(,left ,top ,width ,height) (cl-cdadr (frame-monitor-attributes frame)))
-               (right (+ left width -1))
-               (bottom (+ top height -1))
-               (fr-left (frameset--compute-pos (frame-parameter frame 'left) left right))
-               (fr-top (frameset--compute-pos (frame-parameter frame 'top) top bottom))
+               (right (+ left width -1))
+               (bottom (+ top height -1))
+               (fr-left (frameset--compute-pos (frame-parameter frame 'left) left right))
+               (fr-top (frameset--compute-pos (frame-parameter frame 'top) top bottom))
                (ch-width (frame-char-width frame))
                (ch-height (frame-char-height frame))
-               (fr-width (max (frame-pixel-width frame) (* ch-width (frame-width frame))))
-               (fr-height (max (frame-pixel-height frame) (* ch-height (frame-height frame))))
-               (fr-right (+ fr-left fr-width -1))
-               (fr-bottom (+ fr-top fr-height -1)))
+               (fr-width (max (frame-pixel-width frame) (* ch-width (frame-width frame))))
+               (fr-height (max (frame-pixel-height frame) (* ch-height (frame-height frame))))
+               (fr-right (+ fr-left fr-width -1))
+               (fr-bottom (+ fr-top fr-height -1)))
     (when (pcase force-onscreen
+            ;; A predicate.
+            ((pred functionp)
+             (funcall force-onscreen
+                      frame
+                      (list fr-left fr-top fr-width fr-height)
+                      (list left top width height)))
             ;; Any corner is outside the screen.
-            (`all (or (< fr-bottom top)  (> fr-bottom bottom)
+            (:all (or (< fr-bottom top)  (> fr-bottom bottom)
                       (< fr-left   left) (> fr-left   right)
                       (< fr-right  left) (> fr-right  right)
-                      (< fr-top    top)  (> fr-top    bottom)))
+                      (< fr-top    top)  (> fr-top    bottom)))
             ;; Displaced to the left, right, above or below the screen.
-            (`t   (or (> fr-left   right)
+            (`t   (or (> fr-left   right)
                       (< fr-right  left)
-                      (> fr-top    bottom)
+                      (> fr-top    bottom)
                       (< fr-bottom top)))
             ;; Fully inside, no need to do anything.
             (_ nil))
@@ -430,8 +455,8 @@ is the parameter list of the frame being restored.  Internal use only."
            ;; M-x desktop-read).
            (setq frame (frameset--find-frame
                         (lambda (f id)
-                          (string= (frame-parameter f 'frame-id) id))
-                        display (cdr (assq 'frame-id frame-cfg))))
+                          (string= (frame-parameter f 'frameset--id) id))
+                        display (cdr (assq 'frameset--id frame-cfg))))
            ;; If it has not been loaded, and it is not a minibuffer-only frame,
            ;; let's look for an existing non-minibuffer-only frame to reuse.
            (unless (or frame (eq (cdr (assq 'minibuffer frame-cfg)) 'only))
@@ -447,11 +472,11 @@ is the parameter list of the frame being restored.  Internal use only."
            ;; and that they are linked to the right minibuffer frame.
            (setq frame (frameset--find-frame
                         (lambda (f id mini-id)
-                          (and (string= (frame-parameter f 'frame-id) id)
+                          (and (string= (frame-parameter f 'frameset--id) id)
                                (string= (frame-parameter (window-frame (minibuffer-window f))
-                                                         'frame-id)
+                                                         'frameset--id)
                                         mini-id)))
-                        display (cdr (assq 'frame-id frame-cfg)) (cdr mini))))
+                        display (cdr (assq 'frameset--id frame-cfg)) (cdr mini))))
           (t
            ;; Default to just finding a frame in the same display.
            (setq frame (frameset--find-frame nil display))))
@@ -460,11 +485,21 @@ is the parameter list of the frame being restored.  Internal use only."
       (setq frameset--reuse-list (delq frame frameset--reuse-list)))
     frame))
 
+(defun frameset--initial-params (frame-cfg)
+  "Return parameters from FRAME-CFG that should not be changed later.
+Setting position and size parameters as soon as possible helps reducing
+flickering; other parameters, like `minibuffer' and `border-width', must
+be set when creating the frame because they can not be changed later.
+Internal use only."
+  (cl-loop for param in '(left top with height border-width minibuffer)
+           collect (assq param frame-cfg)))
+
 (defun frameset--get-frame (frame-cfg window-cfg filters force-onscreen)
   "Set up and return a frame according to its saved state.
 That means either reusing an existing frame or creating one anew.
 FRAME-CFG is the frame's parameter list; WINDOW-CFG is its window state.
-For the meaning of FORCE-ONSCREEN, see `frameset-restore'."
+For the meaning of FORCE-ONSCREEN, see `frameset-restore'.
+Internal use only."
   (let* ((fullscreen (cdr (assq 'fullscreen frame-cfg)))
          (lines (assq 'tool-bar-lines frame-cfg))
          (filtered-cfg (frameset-filter-params frame-cfg filters nil))
@@ -507,9 +542,7 @@ For the meaning of FORCE-ONSCREEN, see `frameset-restore'."
                          (frameset--reuse-frame display filtered-cfg))
                     (make-frame-on-display display
                                            (cons '(visibility)
-                                                 (cl-loop
-                                                  for param in '(left top width height minibuffer)
-                                                  collect (assq param filtered-cfg))))))
+                                                 (frameset--initial-params filtered-cfg)))))
     (modify-frame-parameters frame
                              (if (eq (frame-parameter frame 'fullscreen) fullscreen)
                                  ;; Workaround for bug#14949
@@ -541,6 +574,12 @@ It sorts minibuffer-owning frames before minibufferless ones."
           ((eq hasmini1 nil) (string< id-def1 id-def2))
           (t t))))
 
+(defun frameset-keep-original-display-p (force-display)
+  "True if saved frames' displays should be honored."
+  (cond ((daemonp) t)
+        ((eq system-type 'windows-nt) nil)
+        (t (not force-display))))
+
 (defun frameset-sort-frames-for-deletion (frame1 _frame2)
   "Predicate to sort live frames for deletion.
 Minibufferless frames must go first to avoid errors when attempting
@@ -548,42 +587,53 @@ to delete a frame whose minibuffer window is used by another frame."
   (not (frame-parameter frame1 'minibuffer)))
 
 ;;;###autoload
-(cl-defun frameset-restore (frameset &key filters reuse-frames force-display force-onscreen)
+(cl-defun frameset-restore (frameset
+                            &key filters reuse-frames force-display force-onscreen)
   "Restore a FRAMESET into the current display(s).
 
 FILTERS is an alist of parameter filters; defaults to `frameset-filter-alist'.
 
 REUSE-FRAMES describes how to reuse existing frames while restoring a frameset:
-  t       Reuse any existing frame if possible; delete leftover frames.
-  nil     Restore frameset in new frames and delete existing frames.
-  keep    Restore frameset in new frames and keep the existing ones.
-  LIST    A list of frames to reuse; only these will be reused, if possible,
-            and any leftover one will be deleted; other frames not on this
-            list will be kept.
+  t        Reuse any existing frame if possible; delete leftover frames.
+  nil      Restore frameset in new frames and delete existing frames.
+  :keep    Restore frameset in new frames and keep the existing ones.
+  LIST     A list of frames to reuse; only these will be reused, if possible,
+             and any leftover one will be deleted; other frames not on this
+             list will be kept.
 
 FORCE-DISPLAY can be:
-  t       Frames will be restored in the current display.
-  nil     Frames will be restored, if possible, in their original displays.
-  delete  Frames in other displays will be deleted instead of restored.
+  t        Frames will be restored in the current display.
+  nil      Frames will be restored, if possible, in their original displays.
+  :delete  Frames in other displays will be deleted instead of restored.
+  PRED     A function which will be called with one argument, the parameter
+             list, and must return t, nil or `:delete', as above but affecting
+             only the frame that will be created from that parameter list.
 
 FORCE-ONSCREEN can be:
-  all     Force onscreen any frame fully or partially offscreen.
-  t       Force onscreen only those frames that are fully offscreen.
-  nil     Do not force any frame back onscreen.
+  :all     Force onscreen any frame fully or partially offscreen.
+  t        Force onscreen only those frames that are fully offscreen.
+  nil      Do not force any frame back onscreen.
+  PRED     A function which will be called with three arguments,
+           - the live frame just restored,
+           - a list (LEFT TOP WIDTH HEIGHT), describing the frame,
+           - a list (LEFT TOP WIDTH HEIGHT), describing the workarea,
+           and must return non-nil to force the frame onscreen, nil otherwise.
+
+Note the timing and scope of the operations described above: REUSE-FRAMES
+affects existing frames, FILTERS and FORCE-DISPLAY affect the frame being
+restored before that happens, and FORCE-ONSCREEN affects the frame once
+it has been restored.
 
 All keywords default to nil."
 
   (cl-assert (frameset-p frameset))
 
-  (let* ((delete-saved (eq force-display 'delete))
-         (forcing (not (frameset-keep-original-display-p force-display)))
-         (target (and forcing (cons 'display (frame-parameter nil 'display))))
-         other-frames)
+  (let (other-frames)
 
     ;; frameset--reuse-list is a list of frames potentially reusable.  Later we
     ;; will decide which ones can be reused, and how to deal with any leftover.
     (pcase reuse-frames
-      ((or `nil `keep)
+      ((or `nil `:keep)
        (setq frameset--reuse-list nil
              other-frames (frame-list)))
       ((pred consp)
@@ -604,35 +654,40 @@ All keywords default to nil."
                        ((and d-mini `(,hasmini . ,mb-id))
                         (cdr (assq 'frameset--mini frame-cfg)))
                        (default (and (booleanp mb-id) mb-id))
+                       (force-display (if (functionp force-display)
+                                          (funcall force-display frame-cfg)
+                                        force-display))
                        (frame nil) (to-tty nil))
             ;; Only set target if forcing displays and the target display is different.
-            (if (or (not forcing)
-                    (equal target (or (assq 'display frame-cfg) '(display . nil))))
-                (setq frameset--target-display nil)
-              (setq frameset--target-display target
-                    to-tty (null (cdr target))))
-            ;; If keeping non-reusable frames, and the frame-id of one of them
-            ;; matches the frame-id of a frame being restored (because, for example,
-            ;; the frameset has already been read in the same session), remove the
-            ;; frame-id from the non-reusable frame, which is not useful anymore.
-            (when (and other-frames
-                       (or (eq reuse-frames 'keep) (consp reuse-frames)))
-              (let ((dup (cl-find (cdr (assq 'frameset-frame-id frame-cfg))
-                                  other-frames
-                                  :key (lambda (frame)
-                                         (frame-parameter frame 'frameset-frame-id))
-                                  :test #'string=)))
-                (when dup
-                  (set-frame-parameter dup 'frameset-frame-id nil))))
+            (cond ((frameset-keep-original-display-p force-display)
+                   (setq frameset--target-display nil))
+                  ((eq (frame-parameter nil 'display) (cdr (assq 'display frame-cfg)))
+                   (setq frameset--target-display nil))
+                  (t
+                   (setq frameset--target-display (cons 'display
+                                                        (frame-parameter nil 'display))
+                         to-tty (null (cdr frameset--target-display)))))
             ;; Time to restore frames and set up their minibuffers as they were.
             ;; We only skip a frame (thus deleting it) if either:
             ;; - we're switching displays, and the user chose the option to delete, or
             ;; - we're switching to tty, and the frame to restore is minibuffer-only.
             (unless (and frameset--target-display
-                         (or delete-saved
+                         (or (eq force-display :delete)
                              (and to-tty
                                   (eq (cdr (assq 'minibuffer frame-cfg)) 'only))))
-
+              ;; If keeping non-reusable frames, and the frameset--id of one of them
+              ;; matches the id of a frame being restored (because, for example, the
+              ;; frameset has already been read in the same session), remove the
+              ;; frameset--id from the non-reusable frame, which is not useful anymore.
+              (when (and other-frames
+                         (or (eq reuse-frames :keep) (consp reuse-frames)))
+                (let ((dup (cl-find (cdr (assq 'frameset--id frame-cfg))
+                                    other-frames
+                                    :key (lambda (frame)
+                                           (frame-parameter frame 'frameset--id))
+                                    :test #'string=)))
+                  (when dup
+                    (set-frame-parameter dup 'frameset--id nil))))
               ;; Restore minibuffers.  Some of this stuff could be done in a filter
               ;; function, but it would be messy because restoring minibuffers affects
               ;; global state; it's best to do it here than add a bunch of global
@@ -647,7 +702,7 @@ All keywords default to nil."
                (t ;; Frame depends on other frame's minibuffer window.
                 (let* ((mb-frame (or (cl-find-if
                                       (lambda (f)
-                                        (string= (frame-parameter f 'frame-id)
+                                        (string= (frame-parameter f 'frameset--id)
                                                  mb-id))
                                       (frame-list))
                                      (error "Minibuffer frame %S not found" mb-id)))
@@ -658,14 +713,14 @@ All keywords default to nil."
                     (error "Not a minibuffer window %s" mb-window))
                   (if mb-param
                       (setcdr mb-param mb-window)
-                    (push (cons 'minibuffer mb-window) frame-cfg))))))
-            ;; OK, we're ready at last to create (or reuse) a frame and
-            ;; restore the window config.
-            (setq frame (frameset--get-frame frame-cfg window-cfg
-                                             (or filters frameset-filter-alist)
-                                             force-onscreen))
-            ;; Set default-minibuffer if required.
-            (when default (setq default-minibuffer-frame frame)))
+                    (push (cons 'minibuffer mb-window) frame-cfg)))))
+              ;; OK, we're ready at last to create (or reuse) a frame and
+              ;; restore the window config.
+              (setq frame (frameset--get-frame frame-cfg window-cfg
+                                               (or filters frameset-filter-alist)
+                                               force-onscreen))
+              ;; Set default-minibuffer if required.
+              (when default (setq default-minibuffer-frame frame))))
         (error
          (delay-warning 'frameset (error-message-string err) :error))))
 
@@ -674,7 +729,7 @@ All keywords default to nil."
     (sit-for 0 t)
 
     ;; Delete remaining frames, but do not fail if some resist being deleted.
-    (unless (eq reuse-frames 'keep)
+    (unless (eq reuse-frames :keep)
       (dolist (frame (sort (nconc (if (listp reuse-frames) nil other-frames)
                                   frameset--reuse-list)
                            #'frameset-sort-frames-for-deletion))