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* new `pcase-let' syntax hotter than TikTok girls?
@ 2022-11-23 10:26 Emanuel Berg
  2022-11-24 19:06 ` new `pcase-let' syntax Philip Kaludercic
  0 siblings, 1 reply; 4+ messages in thread
From: Emanuel Berg @ 2022-11-23 10:26 UTC (permalink / raw)
  To: help-gnu-emacs; +Cc: Andreas, Jovelou, Ladbon, Pebben, Per

Check out this syntax with `pcase-let'! :O

(pcase-let ((`(,up ,down) (if button
                             `(,#'backward-button ,#'forward-button)
                           `(,#'previous-line ,#'forward-line) ))) ... )

Advantage: A single test (here, `if') but without the bulky
and ugly combo with `let*' and `car'/`cadr' ...

Here is an example how it can be used, and actually is used already [1]

(defun set-vertical-keys (kmap &optional button np tab)
  (pcase-let ((`(,up ,down) (if button
                               `(,#'backward-button ,#'forward-button)
                             `(,#'previous-line ,#'forward-line) )))
    (define-key kmap "i" up)
    (define-key kmap "k" down)
    (when np
      (define-key kmap "p" up)
      (define-key kmap "n" down) )
    (when tab
      (define-key kmap [backtab] up)
      (define-key kmap "\t"      down) )))

and then for example [2]

(let ((kmap Buffer-menu-mode-map))
  (set-vertical-keys kmap nil nil t)
  ;; ...
  )

Too sexy for its shirt!

[1] https://dataswamp.org/~incal/emacs-init/scroll.el
[2] https://dataswamp.org/~incal/emacs-init/buffer-menu.el

-- 
underground experts united
https://dataswamp.org/~incal




^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: new `pcase-let' syntax
  2022-11-23 10:26 new `pcase-let' syntax hotter than TikTok girls? Emanuel Berg
@ 2022-11-24 19:06 ` Philip Kaludercic
  2022-11-24 20:28   ` [External] : " Drew Adams
  0 siblings, 1 reply; 4+ messages in thread
From: Philip Kaludercic @ 2022-11-24 19:06 UTC (permalink / raw)
  To: help-gnu-emacs


Emanuel Berg <incal@dataswamp.org> writes:

> Check out this syntax with `pcase-let'! :O
>
> (pcase-let ((`(,up ,down) (if button
>                              `(,#'backward-button ,#'forward-button)
>                            `(,#'previous-line ,#'forward-line) ))) ... )

In what sense is this new?

I also get the feeling this is a hack for the sake of a hack.  Is it
really that much better than the "classical"

--8<---------------cut here---------------start------------->8---
(let ((up #'previous-line) (down #'forward-line))
  (when button
    (setq up #'backward-button down #'forward-button))
  ;; ...
  )
--8<---------------cut here---------------end--------------->8---



^ permalink raw reply	[flat|nested] 4+ messages in thread

* RE: [External] : Re: new `pcase-let' syntax
  2022-11-24 19:06 ` new `pcase-let' syntax Philip Kaludercic
@ 2022-11-24 20:28   ` Drew Adams
  2022-11-26 16:01     ` Emanuel Berg
  0 siblings, 1 reply; 4+ messages in thread
From: Drew Adams @ 2022-11-24 20:28 UTC (permalink / raw)
  To: Philip Kaludercic, help-gnu-emacs

> > (pcase-let ((`(,up ,down)
> >             (if button
> >                 `(,#'backward-button ,#'forward-button)
> >               `(,#'previous-line ,#'forward-line)))) ...)
> 
> In what sense is this new?
> I also get the feeling this is a hack for the sake of a hack.  Is it
> really that much better than the "classical"
> 
> (let ((up #'previous-line) (down #'forward-line))
>   (when button (setq up #'backward-button down #'forward-button))...)

It gives you more opportunities to
use your `,', ``', and `)' keys?



^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [External] : Re: new `pcase-let' syntax
  2022-11-24 20:28   ` [External] : " Drew Adams
@ 2022-11-26 16:01     ` Emanuel Berg
  0 siblings, 0 replies; 4+ messages in thread
From: Emanuel Berg @ 2022-11-26 16:01 UTC (permalink / raw)
  To: help-gnu-emacs

Drew Adams wrote:

>>> (pcase-let ((`(,up ,down)
>>>             (if button
>>>                 `(,#'backward-button ,#'forward-button)
>>>               `(,#'previous-line ,#'forward-line)))) ...)
>> 
>> [...] I also get the feeling this is a hack for the sake of
>> a hack. Is it really that much better than the "classical"
>> 
>> (let ((up #'previous-line) (down #'forward-line))
>>   (when button (setq up #'backward-button down #'forward-button))...)
>
> It gives you more opportunities to use your `,', ``', and
> `)' keys?

Okay, so how do you do this the classical way then?

(pcase-let*((`(,sail ,ho) (if t '(1 2) '(3 4)))
            (msg (format "%s is %s" sail ho)) )
  msg)

Also, it's better than `let' and `setq' because if you make
a typo setq creates a global variable, a bug that silently
enters your code.

Obviously if you gonna do typos all day ever day that's gonna
be a problem even with pcase-let LOL

-- 
underground experts united
https://dataswamp.org/~incal




^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2022-11-26 16:01 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-11-23 10:26 new `pcase-let' syntax hotter than TikTok girls? Emanuel Berg
2022-11-24 19:06 ` new `pcase-let' syntax Philip Kaludercic
2022-11-24 20:28   ` [External] : " Drew Adams
2022-11-26 16:01     ` Emanuel Berg

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