Re: bug#54764: encode-time: make DST and TIMEZONE fields of the list argument optional ones

[Paul Eggert <eggert@cs.ucla.edu>]

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On 4/30/22 04:22, Max Nikulin wrote:
> 
> I posted a corrected version of my `org-encode-time' macro, but I did 
> not add you to Cc (I sent reply through news.gmane.io), and it has no 
> special case to check whether `encode-time' supports 6 elements list 
> argument:

Thanks, I looked at that and have a couple of questions.

As I understand it, org-encode-time is intended to be a compatibility 
function like org-newline-and-indent and org-string-distance. Those are 
in org-compat.el, so I assumed org-encode-time would be there too.

Also, if the intent is to emulate Emacs 29 encode-time, can't we do 
something like the attached instead? The idea is to implement Emacs 29 
encode-time both on pre-29 Emacs (that don't support lists of length 6) 
and post-29 Emacs (which might drop support for the obsolescent form).

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From 2f44ee7524e5b2e53f912cff1276f7817495c657 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Sat, 30 Apr 2022 19:27:15 -0700
Subject: [PATCH] org-encode-time compatibility function

* lisp/org/org-compat.el (org-encode-time): New function.
---
 lisp/org/org-compat.el | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/lisp/org/org-compat.el b/lisp/org/org-compat.el
index 3e394fbab1..0a0025fa0d 100644
--- a/lisp/org/org-compat.el
+++ b/lisp/org/org-compat.el
@@ -144,6 +144,16 @@ org-file-has-changed-p--hash-table
   (defun org-time-convert-to-list (time)
     (seconds-to-time (float-time time))))
 
+(if (ignore-errors (encode-time '(0 0 0 1 1 1971)))
+    (if (ignore-errors (encode-time 0 0 0 1 1 1971))
+        (defalias 'org-encode-time #'encode-time)
+      (defun org-encode-time (time &rest args)
+        (encode-time (if args (cons time args) time))))
+  (defun org-encode-time (time &rest args)
+    (if args
+        (apply #'encode-time time args)
+      (apply #'encode-time time))))
+
 ;; `newline-and-indent' did not take a numeric argument before 27.1.
 (if (version< emacs-version "27")
     (defsubst org-newline-and-indent (&optional _arg)
-- 
2.34.1