Replace gui-method macros with cl-generic with &context

* lisp/frame.el (gui-method--name, gui-method, gui-method-define)
(gui-method-declare, gui-call): Remove.
(frame-creation-function): Use cl-defgeneric.
(make-frame): Adjust callers.

* lisp/menu-bar.el (menu-bar-edit-menu):
Use gui-backend-selection-exists-p.

* lisp/select.el (x-get-clipboard): Use gui-backend-get-selection.
(gui-backend-get-selection): New cl-generic to replace
gui-get-selection method.
(gui-backend-set-selection): New cl-generic to replace
gui-set-selection method.
(gui-selection-owner-p): New cl-generic to replace
gui-selection-owner-p method.
(gui-backend-selection-exists-p): New cl-generic to replace
gui-selection-exists-p method.  Adjust all callers.

* lisp/server.el (server-create-window-system-frame): Don't ignore
window-system spec even when unsupported.

* lisp/simple.el (deactivate-mark): Use new gui-backend-* functions.

* lisp/startup.el (handle-args-function, window-system-initialization):
Use cl-defgeneric.
(command-line): Adjust calls accordingly.

* lisp/term/ns-win.el (ns-window-system-initialization): Turn into
a window-system-initialization method.
(handle-args-function, frame-creation-function): Use cl-defmethod.
(gui-set-selection, gui-selection-owner-p, gui-selection-exists-p)
(gui-get-selection): Use cl-defmethod on the new functions instead.

* lisp/term/pc-win.el (w16-get-selection-value): Turn into
a gui-backend-get-selection method.
(gui-selection-exists-p, gui-selection-owner-p, gui-set-selection):
Use cl-defmethod on the new functions instead.
(msdos-window-system-initialization): Turn into
a window-system-initialization method.
(frame-creation-function, handle-args-function): Use cl-defmethod.

* lisp/term/w32-win.el (w32-window-system-initialization): Turn into
a window-system-initialization method.
(handle-args-function, frame-creation-function): Use cl-defmethod.
(gui-set-selection, gui-selection-owner-p, gui-selection-exists-p)
(gui-get-selection): Use cl-defmethod on the new functions instead.

* lisp/term/x-win.el (x-window-system-initialization): Turn into
a window-system-initialization method.
(handle-args-function, frame-creation-function): Use cl-defmethod.
(gui-set-selection, gui-selection-owner-p, gui-selection-exists-p)
(gui-get-selection): Use cl-defmethod on the new functions instead.

* lisp/term/xterm.el (xterm--set-selection): Turn into
a gui-backend-set-selection method.

* src/nsselect.m (Fns_selection_exists_p): Remove unused arg `terminal'.
(Fns_selection_owner_p): Remove unused arg `terminal'.
(Fns_get_selection): Remove unused args `time_stamp' and `terminal'.

5 files changed, 126 insertions, 78 deletions

diff --git a/lisp/term/ns-win.el b/lisp/term/ns-win.el
index e642ab53447..f603f3e0f6d 100644
--- a/lisp/term/ns-win.el
+++ b/lisp/term/ns-win.el
@@ -848,7 +848,8 @@ See the documentation of `create-fontset-from-fontset-spec' for the format.")
 
 ;; Do the actual Nextstep Windows setup here; the above code just
 ;; defines functions and variables that we use now.
-(defun ns-initialize-window-system (&optional _display)
+(cl-defmethod window-system-initialization (&context (window-system (eql ns))
+                                            &optional _display)
   "Initialize Emacs for Nextstep (Cocoa / GNUstep) windowing."
   (cl-assert (not ns-initialized))
 
@@ -921,10 +922,11 @@ See the documentation of `create-fontset-from-fontset-spec' for the format.")
 
 ;; Any display name is OK.
 (add-to-list 'display-format-alist '(".*" . ns))
-(gui-method-define handle-args-function ns #'x-handle-args)
-(gui-method-define frame-creation-function ns #'x-create-frame-with-faces)
-(gui-method-define window-system-initialization ns
-                   #'ns-initialize-window-system)
+(cl-defmethod handle-args-function (args &context (window-system (eql ns)))
+  (x-handle-args args))
+
+(cl-defmethod frame-creation-function (params &context (window-system (eql ns)))
+  (x-create-frame-with-faces params))
 
 (declare-function ns-own-selection-internal "nsselect.m" (selection value))
 (declare-function ns-disown-selection-internal "nsselect.m" (selection))
@@ -935,13 +937,22 @@ See the documentation of `create-fontset-from-fontset-spec' for the format.")
 (declare-function ns-get-selection "nsselect.m"
                   (selection-symbol target-type &optional time-stamp terminal))
 
-(gui-method-define gui-set-selection ns
-                   (lambda (selection value)
-                     (if value (ns-own-selection-internal selection value)
-                       (ns-disown-selection-internal selection))))
-(gui-method-define gui-selection-owner-p ns #'ns-selection-owner-p)
-(gui-method-define gui-selection-exists-p ns #'ns-selection-exists-p)
-(gui-method-define gui-get-selection ns #'ns-get-selection)
+(cl-defmethod gui-backend-set-selection (selection value
+                                         &context (window-system (eql ns)))
+  (if value (ns-own-selection-internal selection value)
+    (ns-disown-selection-internal selection)))
+
+(cl-defmethod gui-backend-selection-owner-p (selection
+                                             &context (window-system (eql ns)))
+  (ns-selection-owner-p selection))
+
+(cl-defmethod gui-backend-selection-exists-p (selection
+                                              &context (window-system (eql ns)))
+  (ns-selection-exists-p selection))
+
+(cl-defmethod gui-backend-get-selection (selection-symbol target-type
+                                         &context (window-system (eql ns)))
+  (ns-get-selection selection-symbol target-type))
 
 (provide 'ns-win)
 
diff --git a/lisp/term/pc-win.el b/lisp/term/pc-win.el
index dd4a8ae8d13..b6c7222cdc8 100644
--- a/lisp/term/pc-win.el
+++ b/lisp/term/pc-win.el
@@ -218,8 +218,10 @@ the operating system.")
 ;; From lisp/term/w32-win.el
 ;
 ;;;; Selections
-;
-(defun w16-get-selection-value (_selection-symbol _target-type)
+
+;; gui-get-selection is used in select.el
+(cl-defmethod gui-backend-get-selection (_selection-symbol _target-type
+                                         &context (window-system (eql pc)))
   "Return the value of the current selection.
 Consult the selection.  Treat empty strings as if they were unset."
   ;; Don't die if x-get-selection signals an error.
@@ -228,8 +230,13 @@ Consult the selection.  Treat empty strings as if they were unset."
 
 (declare-function w16-selection-exists-p "w16select.c")
 ;; gui-selection-owner-p is used in simple.el.
-(gui-method-define gui-selection-exists-p pc #'w16-selection-exists-p)
-(gui-method-define gui-selection-owner-p pc #'w16-selection-owner-p)
+(cl-defmethod gui-backend-selection-exists-p (selection
+                                              &context (window-system (eql pc)))
+  (w16-selection-exists-p selection))
+
+(cl-defmethod gui-backend-selection-owner-p (selection
+                                             &context (window-system (eql pc)))
+  (w16-selection-owner-p selection))
 
 (defun w16-selection-owner-p (_selection)
   ;; FIXME: Other systems don't obey select-enable-clipboard here.
@@ -250,19 +257,16 @@ Consult the selection.  Treat empty strings as if they were unset."
 ;; gui-set-selection is used in gui-set-selection.
 (declare-function w16-set-clipboard-data "w16select.c"
 		  (string &optional ignored))
-(gui-method-define gui-set-selection pc
-                   (lambda (selection value)
-                     (if (not value)
-                         (if (w16-selection-owner-p selection)
-                             t)
-                       ;; FIXME: Other systems don't obey
-                       ;; gui-select-enable-clipboard here.
-                       (with-demoted-errors "w16-set-clipboard-data: %S"
-                         (w16-set-clipboard-data value))
-                       value)))
-
-;; gui-get-selection is used in select.el
-(gui-method-define gui-get-selection pc #'w16-get-selection-value)
+(cl-defmethod gui-backend-set-selection (selection value
+                                         &context (window-system (eql pc)))
+  (if (not value)
+      (if (w16-selection-owner-p selection)
+          t)
+    ;; FIXME: Other systems don't obey
+    ;; gui-select-enable-clipboard here.
+    (with-demoted-errors "w16-set-clipboard-data: %S"
+      (w16-set-clipboard-data value))
+    value))
 
 ;; From src/fontset.c:
 (fset 'query-fontset 'ignore)
@@ -310,15 +314,15 @@ This is used by `msdos-show-help'.")
 
 ;; Initialization.
 ;; ---------------------------------------------------------------------------
-;; This function is run, by faces.el:tty-create-frame-with-faces, only
-;; for the initial frame (on each terminal, but we have only one).
+;; This function is run, by the tty method of `frame-creation-function'
+;; (in faces.el), only for the initial frame (on each terminal, but we have
+;; only one).
 ;; This works by setting the `terminal-initted' terminal parameter to
-;; this function, the first time `tty-create-frame-with-faces' is
-;; called on that terminal.  `tty-create-frame-with-faces' is called
-;; directly from startup.el and also by `make-frame' through
-;; `frame-creation-function-alist'.  `make-frame' will call this
-;; function if `msdos-create-frame-with-faces' (see below) is not
-;; found in `frame-creation-function-alist', which means something is
+;; this function, the first time `frame-creation-function' is
+;; called on that terminal.  `frame-creation-function' is called
+;; directly from startup.el and also by `make-frame'.
+;; `make-frame' should call our own `frame-creation-function' method instead
+;; (see below) so if terminal-init-internal is called it means something is
 ;; _very_ wrong, because "internal" terminal emulator should not be
 ;; turned on if our window-system is not `pc'.  Therefore, the only
 ;; Right Thing for us to do here is scream bloody murder.
@@ -328,7 +332,9 @@ Errors out because it is not supposed to be called, ever."
   (error "terminal-init-internal called for window-system `%s'"
 	 (window-system)))
 
-(defun msdos-initialize-window-system (&optional _display)
+;; window-system-initialization is called by startup.el:command-line.
+(cl-defmethod window-system-initialization (&context (window-system (eql pc))
+                                            &optional _display)
   "Initialization function for the `pc' \"window system\"."
   (or (eq (window-system) 'pc)
       (error
@@ -370,17 +376,14 @@ Errors out because it is not supposed to be called, ever."
   (menu-bar-enable-clipboard)
   (run-hooks 'terminal-init-msdos-hook))
 
-;; frame-creation-function-alist is examined by frame.el:make-frame.
-(gui-method-define frame-creation-function
-                   pc #'msdos-create-frame-with-faces)
-;; window-system-initialization-alist is examined by startup.el:command-line.
-(gui-method-define window-system-initialization
-                   pc #'msdos-initialize-window-system)
+;; frame-creation-function is called by frame.el:make-frame.
+(cl-defmethod frame-creation-function (params &context (window-system (eql pc)))
+  (msdos-create-frame-with-faces params))
+
 ;; We don't need anything beyond tty-handle-args for handling
 ;; command-line argument; see startup.el.
-(gui-method-define handle-args-function pc #'tty-handle-args)
-
-
+(cl-defmethod handle-args-function (args &context (window-system (eql pc)))
+  (tty-handle-args args))
 
 ;; ---------------------------------------------------------------------------
 
diff --git a/lisp/term/w32-win.el b/lisp/term/w32-win.el
index b0667e6c4f7..8bbc3ddf10d 100644
--- a/lisp/term/w32-win.el
+++ b/lisp/term/w32-win.el
@@ -290,7 +290,8 @@ See the documentation of `create-fontset-from-fontset-spec' for the format.")
 (declare-function x-parse-geometry "frame.c" (string))
 (defvar x-command-line-resources)
 
-(defun w32-initialize-window-system (&optional _display)
+(cl-defmethod window-system-initialization (&context (window-system (eql w32))
+                                            &optional _display)
   "Initialize Emacs for W32 GUI frames."
   (cl-assert (not w32-initialized))
 
@@ -376,11 +377,11 @@ See the documentation of `create-fontset-from-fontset-spec' for the format.")
   (setq w32-initialized t))
 
 (add-to-list 'display-format-alist '("\\`w32\\'" . w32))
-(gui-method-define handle-args-function w32 #'x-handle-args)
-(gui-method-define frame-creation-function w32
-                   #'x-create-frame-with-faces)
-(gui-method-define window-system-initialization w32
-                   #'w32-initialize-window-system)
+(cl-defmethod handle-args-function (args &context (window-system (eql w32)))
+  (x-handle-args args))
+
+(cl-defmethod frame-creation-function (params &context (window-system (eql w32)))
+  (x-create-frame-with-faces params))
 
 ;;;; Selections
 
@@ -406,18 +407,41 @@ See the documentation of `create-fontset-from-fontset-spec' for the format.")
   (and (memq selection '(nil PRIMARY SECONDARY))
        (get 'x-selections (or selection 'PRIMARY))))
 
-(gui-method-define gui-set-selection w32 #'w32--set-selection)
-(gui-method-define gui-get-selection w32 #'w32--get-selection)
+(cl-defmethod gui-backend-set-selection (type value
+                                         &context (window-system (eql w32)))
+  (w32--set-selection type value))
+
+(cl-defmethod gui-backend-get-selection (type data-type
+                                         &context (window-system (eql w32)))
+  (w32--get-selection type data-type))
+
+(cl-defmethod gui-backend-selection-owner-p (selection
+                                             &context (window-system (eql w32)))
+  (w32--selection-owner-p selection))
 
-(gui-method-define gui-selection-owner-p w32 #'w32--selection-owner-p)
-(gui-method-define gui-selection-exists-p w32 #'w32-selection-exists-p)
+(cl-defmethod gui-backend-selection-exists-p (selection
+                                              &context (window-system (eql w32)))
+  (w32-selection-exists-p selection))
 
 (when (eq system-type 'windows-nt)
   ;; Make copy&pasting in w32's console interact with the system's clipboard!
-  (gui-method-define gui-set-selection nil #'w32--set-selection)
-  (gui-method-define gui-get-selection nil #'w32--get-selection)
-  (gui-method-define gui-selection-owner-p nil #'w32--selection-owner-p)
-  (gui-method-define gui-selection-exists-p nil #'w32-selection-exists-p))
+  ;; We could move those cl-defmethods outside of the `when' and use
+  ;; "&context (system-type (eql windows-nt))" instead!
+  (cl-defmethod gui-backend-set-selection (type value
+                                           &context (window-system (eql nil)))
+    (w32--set-selection type value))
+
+  (cl-defmethod gui-backend-get-selection (type data-type
+                                           &context (window-system (eql nil)))
+    (w32--get-selection type data-type))
+
+  (cl-defmethod gui-backend-selection-owner-p (selection
+                                               &context (window-system (eql nil)))
+    (w32--selection-owner-p selection))
+
+  (cl-defmethod gui-selection-exists-p (selection
+                                        &context (window-system (eql nil)))
+    (w32-selection-exists-p selection)))
 
 ;; The "Windows" keys on newer keyboards bring up the Start menu
 ;; whether you want it or not - make Emacs ignore these keystrokes
diff --git a/lisp/term/x-win.el b/lisp/term/x-win.el
index f929288d04e..39145ff81e6 100644
--- a/lisp/term/x-win.el
+++ b/lisp/term/x-win.el
@@ -29,8 +29,7 @@
 ;; Beginning in Emacs 23, the act of loading this file should not have
 ;; the side effect of initializing the window system or processing
 ;; command line arguments (this file is now loaded in loadup.el).  See
-;; the variables `handle-args-function-alist' and
-;; `window-system-initialization-alist' for more details.
+;; `handle-args-function' and `window-system-initialization' for more details.
 
 ;; startup.el will then examine startup files, and eventually call the hooks
 ;; which create the first window(s).
@@ -1206,7 +1205,8 @@ This returns an error if any Emacs frames are X frames."
 (defvar x-display-name)
 (defvar x-command-line-resources)
 
-(defun x-initialize-window-system (&optional display)
+(cl-defmethod window-system-initialization (&context (window-system (eql x))
+                                            &optional display)
   "Initialize Emacs for X frames and open the first connection to an X server."
   (cl-assert (not x-initialized))
 
@@ -1335,17 +1335,29 @@ This returns an error if any Emacs frames are X frames."
 		  (selection-symbol target-type &optional time-stamp terminal))
 
 (add-to-list 'display-format-alist '("\\`[^:]*:[0-9]+\\(\\.[0-9]+\\)?\\'" . x))
-(gui-method-define handle-args-function x #'x-handle-args)
-(gui-method-define frame-creation-function x #'x-create-frame-with-faces)
-(gui-method-define window-system-initialization x #'x-initialize-window-system)
-
-(gui-method-define gui-set-selection x
-                   (lambda (selection value)
-                     (if value (x-own-selection-internal selection value)
-                       (x-disown-selection-internal selection))))
-(gui-method-define gui-selection-owner-p x #'x-selection-owner-p)
-(gui-method-define gui-selection-exists-p x #'x-selection-exists-p)
-(gui-method-define gui-get-selection x #'x-get-selection-internal)
+(cl-defmethod handle-args-function (args &context (window-system (eql x)))
+  (x-handle-args args))
+
+(cl-defmethod frame-creation-function (params &context (window-system (eql x)))
+  (x-create-frame-with-faces params))
+
+(cl-defmethod gui-backend-set-selection (selection value
+                                         &context (window-system (eql x)))
+  (if value (x-own-selection-internal selection value)
+    (x-disown-selection-internal selection)))
+
+(cl-defmethod gui-backend-selection-owner-p (selection
+                                             &context (window-system (eql x)))
+  (x-selection-owner-p selection))
+
+(cl-defmethod gui-backend-selection-exists-p (selection
+                                              &context (window-system (eql x)))
+  (x-selection-exists-p selection))
+
+(cl-defmethod gui-backend-get-selection (selection-symbol target-type
+                                         &context (window-system (eql x))
+                                         &optional time-stamp terminal)
+  (x-get-selection-internal selection-symbol target-type time-stamp terminal))
 
 ;; Initiate drag and drop
 (add-hook 'after-make-frame-functions 'x-dnd-init-frame)
diff --git a/lisp/term/xterm.el b/lisp/term/xterm.el
index 667e4ce63ee..4e48e80e4e9 100644
--- a/lisp/term/xterm.el
+++ b/lisp/term/xterm.el
@@ -787,9 +787,7 @@ We run the first FUNCTION whose STRING matches the input events."
 
 ;; FIXME: This defines the gui method for all terminals, even tho it only
 ;; supports a subset of them.
-(gui-method-define gui-set-selection nil #'xterm--set-selection)
-
-(defun xterm--set-selection (type data)
+(cl-defmethod gui-backend-set-selection (type data &context (window-system (eql nil)))
   "Copy DATA to the X selection using the OSC 52 escape sequence.
 
 TYPE specifies which selection to set; it must be either