Re: Un-deprecating oset

["Basil L. Contovounesios" <contovob@tcd.ie>]

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Eli Zaretskii <eliz@gnu.org> writes:

>> From: Stefan Monnier <monnier@iro.umontreal.ca>
>> Cc: Jonas Bernoulli <jonas@bernoul.li>,  johnw@gnu.org,  emacs-devel@gnu.org
>> Date: Mon, 25 May 2020 12:06:54 -0400
>> 
>> > I tend to think it should be un-deprecated.
>> 
>> Interesting.  I thought the whole CL -> CL-lib change was because we
>> didn't want to have in Emacs core libraries that stomp on the namespace
>> like that (funnily enough most of EIEIO's global names come straight
>> from Common-Lisp, oref/oset being the main exception ;-)
>> 
>> So does that also mean that EIEIO's names are now accepted into the
>> core namespace?  It seems rather odd that `defclass` is allowed into the
>> core namespace while `defstruct` had to be relegated to `cl-defstruct`.
>
> I didn't mean we should stop cleaning up the global namespace, just
> that this case could be one of the few exclusions.

How's the attached patch for un-deprecating oset and oset-default?

Political rationale:
0. Most voiced opinions have been in favour of keeping oset.
1. Though most are in favour of cleaning EIEIO's namespace,
   deprecating only oset causes hassle without sufficient gain.

Technical rationale:
2. oset is widely used.
3. oref-default is not yet setf-able, so we'd have to recommend using
   eieio-oset-default in place of oset-default, which has been described
   as probably undesirable.

WDYT?

Should the changes to the manuals go to emacs-27 instead of master?

Thanks,

-- 
Basil


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From 5b6eedfee3ac95313d29dca57f56461322dd9b13 Mon Sep 17 00:00:00 2001
From: "Basil L. Contovounesios" <contovob@tcd.ie>
Date: Wed, 3 Jun 2020 14:18:19 +0100
Subject: [PATCH] Fix some EIEIO obsoletions

The deprecation of oset and oset-default was discussed in the
following threads:
https://lists.gnu.org/archive/html/emacs-devel/2020-05/msg00630.html
https://lists.gnu.org/archive/html/emacs-devel/2020-05/msg00674.html

* doc/misc/ede.texi (ede-generic-project): Tidy up example.
* doc/misc/eieio.texi (Accessing Slots): Document oref,
oref-default, and slot-value as generalized variables, and
set-slot-value as obsolete.  Consistently document getters before
setters.
(Predicates): Mention cl-print-object in place of the obsolete
object-print.
(Introspection): Document eieio-class-slots in place of the obsolete
object-slots.

* lisp/emacs-lisp/eieio.el: Un-deprecate oset and oset-default.
Make oref-default setf-able.
* etc/NEWS: Announce this change.

* test/lisp/emacs-lisp/eieio-tests/eieio-tests.el: Use
lexical-binding.
(eieio-test-13-init-methods): Simplify.
(eieio-test-33-instance-tracker): Declare IT-list as special.
---
 doc/misc/ede.texi                             | 10 ++--
 doc/misc/eieio.texi                           | 49 +++++++++++++------
 etc/NEWS                                      |  7 ++-
 lisp/emacs-lisp/eieio.el                      |  7 ++-
 .../emacs-lisp/eieio-tests/eieio-tests.el     |  5 +-
 5 files changed, 49 insertions(+), 29 deletions(-)

diff --git a/doc/misc/ede.texi b/doc/misc/ede.texi
index 584b0d7ee5..412176986c 100644
--- a/doc/misc/ede.texi
+++ b/doc/misc/ede.texi
@@ -955,18 +955,16 @@ ede-generic-project
 ;;; MAKEFILE
 
 (defclass ede-generic-makefile-project (ede-generic-project)
-  ((buildfile :initform "Makefile")
-   )
+  ((buildfile :initform "Makefile"))
   "Generic Project for makefiles.")
 
 (defmethod ede-generic-setup-configuration ((proj ede-generic-makefile-project) config)
-  "Setup a configuration for Make."
+  "Set up a configuration for Make."
   (oset config build-command "make -k")
-  (oset config debug-command "gdb ")
-  )
+  (oset config debug-command "gdb "))
 
 (ede-generic-new-autoloader "generic-makefile" "Make"
-			    "Makefile" 'ede-generic-makefile-project)
+                            "Makefile" 'ede-generic-makefile-project)
 @end example
 
 This example project will detect any directory with the file
diff --git a/doc/misc/eieio.texi b/doc/misc/eieio.texi
index 3943c544c7..06093f7263 100644
--- a/doc/misc/eieio.texi
+++ b/doc/misc/eieio.texi
@@ -698,6 +698,27 @@ Accessing Slots
 referencing vectors (@pxref{Vectors,,,elisp,GNU Emacs Lisp Reference
 Manual}).
 
+@defmac oref obj slot
+@anchor{oref}
+This macro retrieves the value stored in @var{obj} in the slot named
+by @var{slot}.  @var{slot} is the name of the slot when created by
+@dfn{defclass}.
+
+This is a generalized variable that can be used with @code{setf} to
+modify the value stored in @var{slot}.  @xref{Generalized
+Variables,,,elisp,GNU Emacs Lisp Reference Manual}.
+@end defmac
+
+@defmac oref-default class slot
+@anchor{oref-default}
+This macro returns the value of the class-allocated @var{slot} from
+@var{class}.
+
+This is a generalized variable that can be used with @code{setf} to
+modify the value stored in @var{slot}.  @xref{Generalized
+Variables,,,elisp,GNU Emacs Lisp Reference Manual}.
+@end defmac
+
 @defmac oset object slot value
 This macro sets the value behind @var{slot} to @var{value} in
 @var{object}.  It returns @var{value}.
@@ -716,17 +737,6 @@ Accessing Slots
 @end example
 @end defmac
 
-@defmac oref obj slot
-@anchor{oref}
-Retrieve the value stored in @var{obj} in the slot named by @var{slot}.
-Slot is the name of the slot when created by @dfn{defclass}.
-@end defmac
-
-@defmac oref-default class slot
-@anchor{oref-default}
-Get the value of the class-allocated @var{slot} from @var{class}.
-@end defmac
-
 The following accessors are defined by CLOS to reference or modify
 slot values, and use the previously mentioned set/ref routines.
 
@@ -734,14 +744,21 @@ Accessing Slots
 @anchor{slot-value}
 This function retrieves the value of @var{slot} from @var{object}.
 Unlike @code{oref}, the symbol for @var{slot} must be quoted.
+
+This is a generalized variable that can be used with @code{setf} to
+modify the value stored in @var{slot}.  @xref{Generalized
+Variables,,,elisp,GNU Emacs Lisp Reference Manual}.
 @end defun
 
 @defun set-slot-value object slot value
 @anchor{set-slot-value}
-This is not a CLOS function, but is the setter for @code{slot-value}
-used by the @code{setf} macro.  This
-function sets the value of @var{slot} from @var{object}.  Unlike
+This function sets the value of @var{slot} from @var{object}.  Unlike
 @code{oset}, the symbol for @var{slot} must be quoted.
+
+This is not a CLOS function, but is the obsolete setter for
+@code{slot-value} used by the @code{setf} macro.  It is therefore
+recommended to use @code{(setf (slot-value @var{object} @var{slot})
+@var{value})} instead.
 @end defun
 
 @defun slot-makeunbound object slot
@@ -1061,7 +1078,7 @@ Predicates
 Return a string of the form @samp{#<object-class myobjname>} for @var{obj}.
 This should look like Lisp symbols from other parts of Emacs such as
 buffers and processes, and is shorter and cleaner than printing the
-object's record.  It is more useful to use @code{object-print} to get
+object's record.  It is more useful to use @code{cl-print-object} to get
 and object's print form, as this allows the object to add extra display
 information into the symbol.
 @end defun
@@ -1217,7 +1234,7 @@ Introspection
 some functions have been provided.  None of these functions are a part
 of CLOS.
 
-@defun object-slots obj
+@defun eieio-class-slots obj
 Return the list of public slots for @var{obj}.
 @end defun
 
diff --git a/etc/NEWS b/etc/NEWS
index ed4722b27f..27e511047e 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -112,7 +112,12 @@ setting the variable 'auto-save-visited-mode' buffer-locally to nil.
 ** New bindings in occur-mode, 'next-error-no-select' bound to 'n' and
 'previous-error-no-select' bound to 'p'.
 
-** EIEIO: 'oset' and 'oset-default' are declared obsolete.
+** EIEIO
+
++++
+*** The macro 'oref-default' can now be used with 'setf'.
+It is now defined as a generalized variable that can be used with
+'setf' to modify the value stored in a given class slot.
 
 ** New minor mode 'cl-font-lock-built-in-mode' for `lisp-mode'.
 The mode provides refined highlighting of built-in functions, types,
diff --git a/lisp/emacs-lisp/eieio.el b/lisp/emacs-lisp/eieio.el
index ee5dd2cccd..73573a80eb 100644
--- a/lisp/emacs-lisp/eieio.el
+++ b/lisp/emacs-lisp/eieio.el
@@ -513,8 +513,7 @@ oset
   "Set the value in OBJ for slot SLOT to VALUE.
 SLOT is the slot name as specified in `defclass' or the tag created
 with in the :initarg slot.  VALUE can be any Lisp object."
-  (declare (obsolete "use (setf (oref ..) ..) instead" "28.1")
-           (debug (form symbolp form)))
+  (declare (debug (form symbolp form)))
   `(eieio-oset ,obj (quote ,slot) ,value))
 
 (defmacro oset-default (class slot value)
@@ -522,8 +521,7 @@ oset-default
 The default value is usually set with the :initform tag during class
 creation.  This allows users to change the default behavior of classes
 after they are created."
-  (declare (obsolete "use (setf (oref-default ..) ..) instead" "28.1")
-           (debug (form symbolp form)))
+  (declare (debug (form symbolp form)))
   `(eieio-oset-default ,class (quote ,slot) ,value))
 
 ;;; CLOS queries into classes and slots
@@ -654,6 +652,7 @@ object-remove-from-list
 ;; common code between oref and oset, so as to reduce the redundant work done
 ;; in (push foo (oref bar baz)), like we do for the `nth' expander?
 (gv-define-simple-setter eieio-oref eieio-oset)
+(gv-define-simple-setter eieio-oref-default eieio-oset-default)
 
 \f
 ;;;
diff --git a/test/lisp/emacs-lisp/eieio-tests/eieio-tests.el b/test/lisp/emacs-lisp/eieio-tests/eieio-tests.el
index 34c20b2003..21adc91e55 100644
--- a/test/lisp/emacs-lisp/eieio-tests/eieio-tests.el
+++ b/test/lisp/emacs-lisp/eieio-tests/eieio-tests.el
@@ -1,4 +1,4 @@
-;;; eieio-tests.el -- eieio tests routines
+;;; eieio-tests.el -- eieio test routines -*- lexical-binding: t -*-
 
 ;; Copyright (C) 1999-2003, 2005-2010, 2012-2020 Free Software
 ;; Foundation, Inc.
@@ -356,7 +356,7 @@ eieio-test-13-init-methods
     (oset a test-tag 1))
 
   (let ((ca (class-a)))
-    (should-not (/=  (oref ca test-tag) 2))))
+    (should (= (oref ca test-tag) 2))))
 
 \f
 ;;; Perform slot testing
@@ -852,6 +852,7 @@ IT
   "Instance Tracker test object.")
 
 (ert-deftest eieio-test-33-instance-tracker ()
+  (defvar IT-list)
   (let (IT-list IT1)
     (should (setq IT1 (IT)))
     ;; The instance tracker must find this
-- 
2.26.2