Re: Slot accessing issues in EIEIO

[Zhu Zihao <all_but_last@163.com>]

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On Fri, 08 May 2020 11:48:22 +0800,
Stefan Monnier wrote:
> 
> > Maybe we can fix the eieio pattern of pcase.
> >
> > In this piece of code:
> >
> > (defclass test-class () ((slot)))
> >
> > (pcase (make-instance 'test-class)
> >   ((eieio slot)
> >    slot))
> > ;; => unbound
> >
> > An unbound marker will be returned on the fly without running slot-unbound
> > in pcase with eieio pattern. Is it reasonable?
> 
> It should likely obey the bound/unbond distinction, and call
> slot-missing when applicable, yes.  Patch welcome.
> 
> 
>         Stefan
I just give it a try ;)


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From 2fe8fe4c1ae1becb4439bb64576a43ec3fd0b5b7 Mon Sep 17 00:00:00 2001
From: Zhu Zihao <all_but_last@163.com>
Date: Fri, 8 May 2020 17:01:56 +0800
Subject: [PATCH] Make pcase pattern 'eieio' respect slot access related
 functions.

* lisp/emacs-lisp/eieio.el: Make pcase pattern respect slot-missing and
slot-unbound
---
 lisp/emacs-lisp/eieio.el | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/lisp/emacs-lisp/eieio.el b/lisp/emacs-lisp/eieio.el
index fe2b80be01e..999d75f79e9 100644
--- a/lisp/emacs-lisp/eieio.el
+++ b/lisp/emacs-lisp/eieio.el
@@ -359,16 +359,13 @@ eieio
     ;; FIXME: `pcase' does not do a good job here of sharing tests&code among
     ;; various branches.
     `(and (pred eieio-object-p)
-          (app eieio-pcase-slot-index-table ,is)
-          ,@(mapcar (lambda (field)
-                      (let* ((name (if (consp field) (car field) field))
-                             (pat (if (consp field) (cadr field) field))
-                             (i (make-symbol "index")))
-                        `(and (let (and ,i (pred natnump))
-                                (eieio-pcase-slot-index-from-index-table
-                                 ,is ',name))
-                              (app (pcase--flip aref ,i) ,pat))))
-                    fields))))
+        ,@(mapcar (lambda (field)
+                    (pcase-exhaustive field
+                      (`(,name ,pat)
+                        `(app (pcase--flip eieio-oref ',name) ,pat))
+                      ((pred symbolp)
+                       `(app (pcase--flip eieio-oref ',field) ,field))))
+                  fields))))
 \f
 ;;; Simple generators, and query functions.  None of these would do
 ;;  well embedded into an object.
-- 
2.26.2