Re: [PATCH v4] org-encode-time compatibility and convenience helper

[Max Nikulin <manikulin@gmail.com>]

On 11/05/2022 20:20, Ihor Radchenko wrote:
> Max Nikulin writes:
> 
>>> +              ;; In Emacs-27 and Emacs-28 `encode-time' does not support 6 elements
>>> +              ;; list argument so `org-encode-time' can not be outside of `pcase'.
>>> +              (pcase-let
>>> +                  ((`(,_ ,_ ,_ ,d ,m ,y ,dow . ,_) (decode-time start)))
>>> +                (pcase step
>>> +                  (`day (org-encode-time 0 0 org-extend-today-until (1+ d) m y))
>>> +                  (`week
>>> +                   (let ((offset (if (= dow week-start) 7
>>> +                                   (mod (- week-start dow) 7))))
>>> +                     (org-encode-time 0 0 org-extend-today-until (+ d offset) m y)))
>>> +                  (`semimonth (org-encode-time 0 0 0
>>> +                                               (if (< d 16) 16 1)
>>> +                                               (if (< d 16) m (1+ m)) y))
>>> +                  (`month (org-encode-time 0 0 0 month-start (1+ m) y))
>>> +                  (`year (org-encode-time 0 0 org-extend-today-until 1 1 (1+ y))))))
>>
>> I do not like repeating of `org-encode-time' but do not see another way
>> till Emacs-29 will become the lowest supported version.
> 
> This is fine. AFAIK, other parts of time handling code is full of conds
> and pcases.

I mean that before my patch there was single `encode-time' outside of 
`pcase', I replace `list' by `org-encode-time' inside each pattern.

>>> +	    (org-encode-time
>>> +             (apply #'list
>>> +                    (or (car time0) 0)
>>> +                    (+ (if (eq timestamp? 'minute) n 0) (nth 1 time0))
>>> +                    (+ (if (eq timestamp? 'hour) n 0)   (nth 2 time0))
>>> +                    (+ (if (eq timestamp? 'day) n 0)    (nth 3 time0))
>>> +                    (+ (if (eq timestamp? 'month) n 0)  (nth 4 time0))
>>> +                    (+ (if (eq timestamp? 'year) n 0)   (nth 5 time0))
>>> +                    (nthcdr 6 time0))))
>>>         (when (and (memq timestamp? '(hour minute))
>>>   		 extra
>>>   		 (string-match "-\\([012][0-9]\\):\\([0-5][0-9]\\)" extra))
>>
>> I am tempting to write something like
>>
>>     (let* ((ts (copy-sequence time0))
>> 	 (ord (memq timestamp? '(year month day hour minute)))
>> 	 (field (and ord (nthcdr (length ord) ts))))
>>       (when field
>>         (setcar field (+ (car field) n)))
>>       (org-encode-time ts))
>>
>> but I am afraid it will make the code rather obscure.
> 
> Yes, the second version is rather hard to understand. The proper
> solution would be writing (or using) some high-level time handling
> library and then using it in Org. Then, we would not need to deal with
> low-level time representations so frequently.

 From my point of view

   (cl-mapcar
    (lambda (value part)
      (if (and part (eq part timestamp?))
	 (+ n value)
        value))
    time0 '(second minute hour day month year nil nil nil))

is better than the original code, but...

Nicolas Goaziou to emacs-orgmode. [Patch] to correctly sort the items 
with emphasis marks in a list. Mon, 19 Apr 2021 18:08:17 +0200.
https://list.orgmode.org/87r1j6b6ku.fsf@nicolasgoaziou.fr
 >
> I stay away from CL as much as possible, otherwise newcomers will have
> to learn two languages to start contributing, Elisp and CL (cl-loop,
> ewww). CL is still necessary however, as we cannot use `seq' yet.