Re: Insert one of the flags automatically with tab completion.

[Hongyi Zhao <hongyi.zhao@gmail.com>]

On Sat, Oct 23, 2021 at 1:07 PM Hongyi Zhao <hongyi.zhao@gmail.com> wrote:
>
> I noticed the following function defined here[1]:
>
> (defun pw-ATOMIC_POSITIONS ()
>   (interactive)
>   (let ((flag (read-string "Flags: { alat | bohr | angstrom | crystal
> | crystal_sg } ")))
>     (insert "ATOMIC_POSITIONS " flag))
>   (newline 1)
>   )
>
> The above function can only prompt the user to insert one of the flags
> manually. But I want to insert one of the flags automatically with tab
> completion. Any hints for achieving this enhancement?
>
> [1] https://github.com/QEF/q-e/blob/03a7fa640903173662b24e4c30e520c9beaba16d/GUI/QE-modes/qe-modes/qe-funcs.el#L1966

I came up with two solutions:

1. by ido-completing-read

;; http://ergoemacs.org/emacs/elisp_idioms_prompting_input.html
(require 'ido)

(defun my-pw-ATOMIC_POSITIONS1 ()
  (interactive)
  (let ((flag '("alat" "bohr" "angstrom" "crystal" "crystal_sg")))
    (insert "ATOMIC_POSITIONS " (ido-completing-read "Select the flag: " flag)))
  (newline 1))


2. by completing-read

;; https://stackoverflow.com/questions/19772394/elisp-function-select-argument-from-list
(defun my-pw-ATOMIC_POSITIONS2 ()
  (interactive
   (list
    (insert "ATOMIC_POSITIONS "
        (completing-read
         "Select the flag: "
         '(("alat" 1)
           ("bohr" 2)
           ("angstrom" 3)
           ("crystal" 4)
           ("crystal_sg" 5)
           )
         nil t ""))))
  (newline 1))

HZ