Re: favorite subject DWIM

[Emanuel Berg]

Abhiseck Paira wrote:

>> ;;; -*- lexical-binding: t -*-
>> ;;;
>> ;;; this file:
>> ;;;   https://dataswamp.org/~incal/public_html/emacs-init/dwim.el
>
> This file is not found (404).

You are right, here is the correct URL:

  https://dataswamp.org/~incal/emacs-init/dwim.el

I still yank the whole file, last.

>> (defun test-dwim (&optional beg end)
>>   (interactive (when (use-region-p)
>>                  (list (region-beginning) (region-end)) ))
>>   (let ((bg (or beg (point-min)))
>>         (ed (or end (point-max))) )
>>     (list bg ed) ))
>
> Why do you have interactive declaration? [...] Wouldn't most
> of the time this function be called by some other function?

It depends on the actual function but since it involves the
region it is probably used most often interactively.

> Nit-picking: I think the let form is unnecessary.

Here the values are only returned but one can think of more
complicated stuff where the values are used repeatedly.

But actually it isn't a bad thing to be clear about that step
and get it over first thing, it is needed for the &optional
arguments which will be nil if called from Lisp
without arguments.

>> (when nil
>>   (progn
>>     (set-mark 10)
>>     (forward-line 3)
>>     (call-interactively #'test-dwim) ) ; (10 500)
>>
>>   (call-interactively #'test-dwim)     ; ( 1 604)
>>
>>   (test-dwim 30 100)                   ; (30 100)
>>
>>   (test-dwim)                          ; ( 1 604)
>> )
>
> Since I couldn't find your file, I may be lacking context,
> what it seems here you're testing the function?

Yes, as you see it can be used with a region, without a region
(whole buffer acted upon - DWIM), with arguments from Lisp,
and without - in which case again the whole buffer will be
used, so the interactive/no-region is analogous to
from-Lisp/no-arguments.

DWIM!

;;; -*- lexical-binding: t -*-
;;;
;;; this file:
;;;   https://dataswamp.org/~incal/emacs-init/dwim.el

(defun test-dwim (&optional beg end)
  (interactive (when (use-region-p)
                 (list (region-beginning) (region-end)) ))
  (let ((bg (or beg (point-min)))
        (ed (or end (point-max))) )
    (list bg ed) ))

(when nil
  (progn
    (set-mark 10)
    (forward-line 3)
    (call-interactively #'test-dwim) ) ; (10 500)

  (call-interactively #'test-dwim)     ; ( 1 604)

  (test-dwim 30 100)                   ; (30 100)

  (test-dwim)                          ; ( 1 604)
)

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