* lisp/emacs-lisp/eieio.el: Add some default implementations

(standard-class): Mark it obsolete.
(slot-missing): Give it a default implementation.
(destructor): Simplify and mark it obsolete.
(object-print): Give it a default implementation.
(eieio-change-class): Rename from change-class.
(change-class): Redefine as obsolete alias.

2 files changed, 19 insertions, 29 deletions

diff --git a/lisp/emacs-lisp/eieio-core.el b/lisp/emacs-lisp/eieio-core.el
index dcaaab69cf..c54cd22115 100644
--- a/lisp/emacs-lisp/eieio-core.el
+++ b/lisp/emacs-lisp/eieio-core.el
@@ -756,9 +756,7 @@ Argument FN is the function calling this verifier."
 	  ;; The slot-missing method is a cool way of allowing an object author
 	  ;; to intercept missing slot definitions.  Since it is also the LAST
 	  ;; thing called in this fn, its return value would be retrieved.
-	  (slot-missing obj slot 'oref)
-	  ;;(signal 'invalid-slot-name (list (eieio-object-name obj) slot))
-	  )
+	  (slot-missing obj slot 'oref))
       (cl-check-type obj eieio-object)
       (eieio-barf-if-slot-unbound (aref obj c) obj slot 'oref))))
 
@@ -780,9 +778,7 @@ Fills in OBJ's SLOT with its default value."
 	    ;; Oref that slot.
 	    (aref (eieio--class-class-allocation-values cl)
 		  c)
-	  (slot-missing obj slot 'oref-default)
-	  ;;(signal 'invalid-slot-name (list (class-name cl) slot))
-	  )
+	  (slot-missing obj slot 'oref-default))
       (eieio-barf-if-slot-unbound
        (let ((val (cl--slot-descriptor-initform
                    (aref (eieio--class-slots cl)
@@ -822,9 +818,7 @@ Fills in OBJ's SLOT with VALUE."
 	      (aset (eieio--class-class-allocation-values class)
 		    c value))
 	  ;; See oref for comment on `slot-missing'
-	  (slot-missing obj slot 'oset value)
-	  ;;(signal 'invalid-slot-name (list (eieio-object-name obj) slot))
-	  )
+	  (slot-missing obj slot 'oset value))
       (eieio--validate-slot-value class c value slot)
       (aset obj c value))))
 
diff --git a/lisp/emacs-lisp/eieio.el b/lisp/emacs-lisp/eieio.el
index 790e8bc9e0..0ec07fe7b4 100644
--- a/lisp/emacs-lisp/eieio.el
+++ b/lisp/emacs-lisp/eieio.el
@@ -678,7 +678,8 @@ This class is not stored in the `parent' slot of a class vector."
 
 (setq eieio-default-superclass (cl--find-class 'eieio-default-superclass))
 
-(defalias 'standard-class 'eieio-default-superclass)
+(define-obsolete-function-alias 'standard-class
+  'eieio-default-superclass "25.2")
 
 (cl-defgeneric make-instance (class &rest initargs)
   "Make a new instance of CLASS based on INITARGS.
@@ -765,11 +766,7 @@ dynamically set from SLOTS."
   ;; Shared initialize will parse our slots for us.
   (shared-initialize this slots))
 
-(cl-defgeneric slot-missing (object slot-name operation &optional new-value)
-  "Method invoked when an attempt to access a slot in OBJECT fails.")
-
-(cl-defmethod slot-missing ((object eieio-default-superclass) slot-name
-			 _operation &optional _new-value)
+(cl-defgeneric slot-missing (object slot-name _operation &optional _new-value)
   "Method invoked when an attempt to access a slot in OBJECT fails.
 SLOT-NAME is the name of the failed slot, OPERATION is the type of access
 that was requested, and optional NEW-VALUE is the value that was desired
@@ -777,8 +774,9 @@ to be set.
 
 This method is called from `oref', `oset', and other functions which
 directly reference slots in EIEIO objects."
-  (signal 'invalid-slot-name (list (eieio-object-name object)
-				   slot-name)))
+  (signal 'invalid-slot-name
+          (list (if (eieio-object-p object) (eieio-object-name object) object)
+                slot-name)))
 
 (cl-defgeneric slot-unbound (object class slot-name fn)
   "Slot unbound is invoked during an attempt to reference an unbound slot.")
@@ -815,22 +813,19 @@ first and modify the returned object.")
     (if params (shared-initialize nobj params))
     nobj))
 
-(cl-defgeneric destructor (this &rest params)
-  "Destructor for cleaning up any dynamic links to our object.")
-
-(cl-defmethod destructor ((_this eieio-default-superclass) &rest _params)
-  "Destructor for cleaning up any dynamic links to our object.
-Argument THIS is the object being destroyed.  PARAMS are additional
-ignored parameters."
+(cl-defgeneric destructor (_this &rest _params)
+  "Destructor for cleaning up any dynamic links to our object."
+  (declare (obsolete nil "25.2"))
   ;; No cleanup... yet.
-  )
+  nil)
 
-(cl-defgeneric object-print (this &rest strings)
-  "Pretty printer for object THIS.  Call function `object-name' with STRINGS.
+(cl-defgeneric object-print (this &rest _strings)
+  "Pretty printer for object THIS.
 
 It is sometimes useful to put a summary of the object into the
 default #<notation> string when using EIEIO browsing tools.
-Implement this method to customize the summary.")
+Implement this method to customize the summary."
+  (format "%S" this))
 
 (cl-defmethod object-print ((this eieio-default-superclass) &rest strings)
   "Pretty printer for object THIS.  Call function `object-name' with STRINGS.
@@ -938,11 +933,12 @@ this object."
 
 ;;; Unimplemented functions from CLOS
 ;;
-(defun change-class (_obj _class)
+(defun eieio-change-class (_obj _class)
   "Change the class of OBJ to type CLASS.
 This may create or delete slots, but does not affect the return value
 of `eq'."
   (error "EIEIO: `change-class' is unimplemented"))
+(define-obsolete-function-alias 'change-class 'eieio-change-class "25.2")
 
 ;; Hook ourselves into help system for describing classes and methods.
 ;; FIXME: This is not actually needed any more since we can click on the