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Re: [PATCH v4] org-encode-time compatibility and convenience helper
From: |
Ihor Radchenko |
Subject: |
Re: [PATCH v4] org-encode-time compatibility and convenience helper |
Date: |
Wed, 11 May 2022 21:20:51 +0800 |
Max Nikulin <manikulin@gmail.com> writes:
>> + (defmacro org-encode-time (&rest time)
>> + (pcase (length time) ; Emacs-29 since d75e2c12eb
>> + (1 `(encode-time ,@time))
>> + ((or 6 9) `(encode-time (list ,@time)))
>> + (_ (error "`org-encode-time' may be called with 1, 6, or 9
>> arguments but %d given"
>> + (length time)))))
>
> Should it be something like the following?
>
> (signal 'wrong-type-argument (list '(1 6 9) (length time)))
>
> or even
>
> (signal 'wrong-type-argument
> (list '(lambda (n-args) (memq n-args) '(1 6 9)) (length time)))
>
> Usually "wrong type argument" errors give no clue even related to called
> function til enabling enter debugger on error and realizing how to
> reproduce the problem.
The current error is fine. I'd rather propose Emacs to change the "wrong
type argument" message to mention the function name.
>> + ;; 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.
>> + (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.
>> + (org-encode-time
>> + (append '(0)
>> + (mapcar
>> + (lambda (prop) (or (org-element-property prop timestamp) 0))
>> + (if end '(:minute-end :hour-end :day-end :month-end :year-end)
>> + '(:minute-start :hour-start :day-start :month-start
>> + :year-start)))
>> + '(nil -1 nil))))
>>
>> (defun org-timestamp-has-time-p (timestamp)
>> "Non-nil when TIMESTAMP has a time specified."
>
> Hardly may be considered as an example of elegant code.
It is ok. You also could do it as
`(0 ,@(mapcar (lambda (prop) ...) (if ...)) nil -1 nil)
AFAIK, there is nothing much you can improve further without using
function composition from dash.el.
Best,
Ihor