Re: About zcomplete

[Philip Kaludercic <philipk@posteo.net>]

Ergus <spacibba@aol.com> writes:

> Hi recently I have been trying to move back to default completion. As
> I had many issues with fido and icomplete.
>
> The default completion system received a nice improvement recently with
> the completion-autoselect... and I am wondering a simple mode like
> this may be added to vanilla (or at least it gives an idea to a better
> lisper to implement something better, this is just a proof of concept.)
>
> ```
> (require 'simple)
> (require 'minibuffer)
>
> (defvar-keymap zcomplete-map
>    :doc "Keymap used in *Completions* on zcomplete"
>    :parent completion-list-mode-map
>    "z" nil
>    "n" nil
>    "p" nil
>    "q" nil
>    "g" nil
>    "h" nil
>    "DEL" nil
>    )

When completion-auto-select was first added, there was a discussion
about adding automatic narrowing in the *Completions* buffer.  Given a
mode like zcomplete, that decides to unbind all single-character
bindings, this might be possible (as an alternative to what you do in
zcomplete--try-on-minibuffer).

Whether or not this should be coupled to removing the mode line of the
completion buffer is a different question.

> (defun zcomplete--try-on-minibuffer ()
>    "Try to execute the binding on minibuffer."
>    (switch-to-minibuffer)
>    (if-let ((command (lookup-key (current-active-maps)
>                                  (this-single-command-keys))))
>        (progn
>          (minibuffer-hide-completions)
>          (call-interactively command)
>          t)
>      ;; back to completions
>      (switch-to-completions)
>      nil))
>
> (defun zcomplete--completions-pre-hook ()
>    "Try on minibuffer when the command is not in *Completions* map."
>    (when (eq this-command 'undefined)
>      (zcomplete--try-on-minibuffer)))
>
> (defun zcomplete--hack (data context signal)
>    "Alternative to command-error-default-function.
> This will try to execute on minibuffer, else emits the error"
>    (unless (and (string= (buffer-name) "*Completions*")
>                 (zcomplete--try-on-minibuffer))
>      (command-error-default-function data context signal)))
>
> (defun zcomplete--completions-setup-hook ()
>    "To call on completions setup."
>    (add-hook 'pre-command-hook #'zcomplete--completions-pre-hook nil t)
>
>    (setq-local command-error-function #'zcomplete--hack)
>    (setq-local mode-line-format nil)
>    (use-local-map zcomplete-map))
>
> (define-minor-mode zcomplete-mode
>    "Completion highlight mode to enable candidates highlight in the minibuffer."
>    :global t
>    :group 'minibuffer
>
>    (if zcomplete-mode
>        (progn
>          (setq completion-auto-select t)

This should probably be reverted when zcomplete-mode is disabled.

>          ;; (overlay-put zcomplete-overlay 'face 'zcomplete)
> 	(add-hook 'completion-setup-hook #'zcomplete--completions-setup-hook t))
>
>      (remove-hook 'completion-setup-hook #'zcomplete--completions-setup-hook)))
>
> (provide 'zcomplete)
> ```
>
> It lacks some features (like highlight the current candidate or
> automatically update completion buffers when visible) to be really a
> zsh-like feature, but at least we don't need to press C-g every time we
> want to edit the minibuffer.
>
> With this a tab shows the completions and goes there, and any attempt to
> edit or not defined command tries to execute on the minibuffer... 
>
> Parts of this could be implemented with advises, but I know we try to
> avoid those on vanilla code.

If something like this would be added to the core, it would be better to
patch the relevant sections directly.

> WDYT?
> Best,
> Ergus
>
>

-- 
	Philip Kaludercic