new `pcase-let' syntax hotter than TikTok girls?

[Emanuel Berg]

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