vertico crm experiments

crm.el

; some experimental code from minad, to improve CRM experience
(defun vertico--crm-indicator (args)
  "Add prompt indicator, modify ARGS passed to `completing-read-multiple'."
  (cons (concat "[CRM] " (car args)) (cdr args)))

(defun vertico--crm-separator (&rest _)
  "Add separator between selected items, when inserting."
  (when (eq minibuffer-completion-table #'crm--collection-fn)
    ;; You may want to use something else than ", ".
    (insert ", ")))

(defun vertico--crm-remove-selected (candidates)
  "Remove already selected items from the CANDIDATES."
  (if (eq minibuffer-completion-table #'crm--collection-fn)
      (pcase-let*
          ((`(,base ,_ ,all) candidates)
           (items (split-string
                   (substring (minibuffer-contents-no-properties) 0 base)
                   crm-separator t)))
        (setq all (cl-delete-if (lambda (x) (member x items)) all))
        (list base (length all) all))
    candidates))

(advice-add #'completing-read-multiple
            :filter-args #'vertico--crm-indicator)
(advice-add #'vertico-insert
            :after #'vertico--crm-separator)
(advice-add #'vertico--recompute-candidates
            :filter-return #'vertico--crm-remove-selected)

; https://github.com/minad/vertico/issues/1#issuecomment-817378284
; You can write a function which you register as an after-change-function hook in the minibuffer. 
; This function splits the already selected candidates and replaces the candidates with 
; (propertize candidate 'display "short-candidate-version"). 
  (minibuffer-with-setup-hook
      (lambda ()
        (add-hook 'after-change-functions
                  (lambda (&rest _)
                    (save-excursion
                      (save-match-data
                        (let ((pos (minibuffer-prompt-end)))
                          (goto-char pos)
                          (while (< pos (point-max))
                            (when (re-search-forward (concat crm-separator "\\|\\'") nil 'noerror)
                              (when-let (short (cdr (assoc (string-trim (buffer-substring-no-properties
                                                                         pos (match-beginning 0)))
                                                           candidates)))
                                (put-text-property pos (match-beginning 0) 'display short))
                              (setq pos (point))))))))
                  nil 'local))