bug#30202: 27.0.50; Code refactoring on assq-delete-all assoc-delete-all

[Tino Calancha]

X-Debbugs-CC: monnier@iro.umontreal.ca
Severity: wishlist

Hi Stefan,

yesterday was added (how about to announce it in NEWS file?)
the new function `assoc-delete-all', which is pretty much
the same as `assq-delete-all' with `equal' instead of `eq'.

How do you think below patch?
IIUC, the byte compiler will carry the substitution
(funcall function foo bar)
into
(function foo bar)

so that compile code won't suffer the funcall overhead, right?

* `rassq-delete-all' is also very similar, maybe it could also join the
refactoring.

--8<-----------------------------cut here---------------start------------->8---
commit 11e4408e9f35d4da1cf07effda63354dde44d9a6
Author: tino calancha <tino.calancha@gmail.com>
Date:   Mon Jan 22 13:57:37 2018 +0900

    Code refactoring
    
    * lisp/subr.el (alist-delete-all): New defun extracted from
    assq-delete-all.
    (assoc-delete-all, assq-delete-all): Use it.

diff --git a/lisp/subr.el b/lisp/subr.el
index 092850a44d..d8286c0937 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -705,35 +705,33 @@ member-ignore-case
     (setq list (cdr list)))
   list)
 
-(defun assoc-delete-all (key alist)
-  "Delete from ALIST all elements whose car is `equal' to KEY.
+(defun alist-delete-all (key alist function)
+  "Delete from ALIST all elements whose car is KEY.
+Keys are compared with FUNCTION.
 Return the modified alist.
 Elements of ALIST that are not conses are ignored."
   (while (and (consp (car alist))
-             (equal (car (car alist)) key))
+             (funcall function (caar alist) key))
     (setq alist (cdr alist)))
   (let ((tail alist) tail-cdr)
     (while (setq tail-cdr (cdr tail))
       (if (and (consp (car tail-cdr))
-              (equal (car (car tail-cdr)) key))
+              (funcall function (caar tail-cdr) key))
          (setcdr tail (cdr tail-cdr))
        (setq tail tail-cdr))))
   alist)
 
+(defun assoc-delete-all (key alist)
+  "Delete from ALIST all elements whose car is `equal' to KEY.
+Return the modified alist.
+Elements of ALIST that are not conses are ignored."
+  (alist-delete-all key alist #'equal))
+
 (defun assq-delete-all (key alist)
   "Delete from ALIST all elements whose car is `eq' to KEY.
 Return the modified alist.
 Elements of ALIST that are not conses are ignored."
-  (while (and (consp (car alist))
-             (eq (car (car alist)) key))
-    (setq alist (cdr alist)))
-  (let ((tail alist) tail-cdr)
-    (while (setq tail-cdr (cdr tail))
-      (if (and (consp (car tail-cdr))
-              (eq (car (car tail-cdr)) key))
-         (setcdr tail (cdr tail-cdr))
-       (setq tail tail-cdr))))
-  alist)
+  (alist-delete-all key alist #'eq))
 
 (defun rassq-delete-all (value alist)
   "Delete from ALIST all elements whose cdr is `eq' to VALUE.

--8<-----------------------------cut here---------------end--------------->8---


In GNU Emacs 27.0.50 (build 13, x86_64-pc-linux-gnu, GTK+ Version 3.22.11)
 of 2018-01-22 built on calancha-pc
Repository revision: 9fd9d4cf63d96ba9748b9e89137575e386191c82