feature/icomplete-vertical

[Gregory Heytings via "Emacs development discussions." <emacs-devel@gnu.org>]

>
>> If there was a built-in vertical mode it would be better / more 
>> intuitive.
>
> Could you try the branch feature/icomplete-vertical? I need some testers 
> before adding it to master.
>

Alas no, I have been using the following to have icomplete-vertical for 
quite some time, it works perfectly well, so I don't see why a more 
complex implementation would be necessary.

(setq icomplete-prospects-height 6)
(setq icomplete-separator "\n")
(defun icomplete-vertical-minibuffer-setup ()
   (setq truncate-lines t)
   (setq-local completion-ignore-case t)
   (setq-local read-file-name-completion-ignore-case t)
   (setq-local read-buffer-completion-ignore-case t)
   (setq icomplete-hide-common-prefix nil))
(add-hook 'icomplete-minibuffer-setup-hook #'icomplete-vertical-minibuffer-setup)
(defun icomplete-vertical-reformat-completions (completions)
   (save-match-data
     (let ((cnp (substring-no-properties completions)))
       (if (string-match "^\\((.*)\\|\\[.+\\]\\)?{\\(\\(?:.\\|\n\\)+\\)}" cnp)
           (format "%s \n%s"
                   (or (match-string 1 cnp) "")
                   (replace-regexp-in-string "^" (make-string (current-column) ? ) (match-string 2 cnp)))
         cnp))))
(defun icomplete-vertical-adjust-minibuffer-height (completions)
   (let* ((comp (icomplete-vertical-reformat-completions completions))
          (complen (length (split-string comp "\n"))))
     (if (> complen 1) (enlarge-window (- icomplete-prospects-height (1- (window-height)))))
     comp))
(advice-add 'icomplete-completions :filter-return #'icomplete-vertical-adjust-minibuffer-height)