(or emacs irrelevant)

Extended syntax for hydra docstrings

I've been getting more and more organized in tracking my tasks and time with Org-mode. Still using the usual suspects, of course: GTD and Pomodoro, I'm just getting more diligent with them than in the previous years.

So today I wanted to prettify the good old org-agenda-view-mode-dispatch, which is bound to v in org-agenda-mode. Currently, it's just a boring static message and read-char combination. Why not do it with a hydra instead?

Here's the current full code, that uses the newly extended doc syntax:

(define-key org-agenda-mode-map
    "v" 'hydra-org-agenda-view/body)

(defun org-agenda-cts ()
  (let ((args (get-text-property
               (min (1- (point-max)) (point))
    (nth 2 args)))

(defhydra hydra-org-agenda-view (:hint nil)
_d_: ?d? day        _g_: time grid=?g? _a_: arch-trees
_w_: ?w? week       _[_: inactive      _A_: arch-files
_t_: ?t? fortnight  _f_: follow=?f?    _r_: report=?r?
_m_: ?m? month      _e_: entry =?e?    _D_: diary=?D?
_y_: ?y? year       _q_: quit          _L__l__c_: ?l?"
  ("SPC" org-agenda-reset-view)
  ("d" org-agenda-day-view
       (if (eq 'day (org-agenda-cts))
           "[x]" "[ ]"))
  ("w" org-agenda-week-view
       (if (eq 'week (org-agenda-cts))
           "[x]" "[ ]"))
  ("t" org-agenda-fortnight-view
       (if (eq 'fortnight (org-agenda-cts))
           "[x]" "[ ]"))
  ("m" org-agenda-month-view
       (if (eq 'month (org-agenda-cts)) "[x]" "[ ]"))
  ("y" org-agenda-year-view
       (if (eq 'year (org-agenda-cts)) "[x]" "[ ]"))
  ("l" org-agenda-log-mode
       (format "% -3S" org-agenda-show-log))
  ("L" (org-agenda-log-mode '(4)))
  ("c" (org-agenda-log-mode 'clockcheck))
  ("f" org-agenda-follow-mode
       (format "% -3S" org-agenda-follow-mode))
  ("a" org-agenda-archives-mode)
  ("A" (org-agenda-archives-mode 'files))
  ("r" org-agenda-clockreport-mode
       (format "% -3S" org-agenda-clockreport-mode))
  ("e" org-agenda-entry-text-mode
       (format "% -3S" org-agenda-entry-text-mode))
  ("g" org-agenda-toggle-time-grid
       (format "% -3S" org-agenda-use-time-grid))
  ("D" org-agenda-toggle-diary
       (format "% -3S" org-agenda-include-diary))
  ("!" org-agenda-toggle-deadlines)
   (let ((org-agenda-include-inactive-timestamps t))
     (org-agenda-check-type t 'timeline 'agenda)
  ("q" (message "Abort") :exit t))

And here's how it looks like in action, I simply pressed v while in the agenda:


Since many functions that org-agenda-view-mode-dispatch calls are toggles, it makes sense for hydra-org-agenda-view to display the status of these toggles.

And it's actually convenient to toggle a whole lot of things at once, and the default red hydra keys really come in handy here.

Quick explanation of the syntax

Each head of a hydra looks like:

(key cmd &optional doc &rest plist)

The fairly new bit that I'm using here is the ability to use a sexp instead of a plain string in the doc part. This sexp will be evaluated each time the doc is re-displayed. This means that it can represent a changing variable, for instance the state of a minor mode or a variable.

And here's the best part: the doc of each head can be quoted in the hydra's docstring by using the corresponding key, e.g. ?g?. This allows to have very complex docstrings while keeping them easily aligned in a tabular format.

Here is only the hydra's docstring, copied from the above code:

_d_: ?d? day        _g_: time grid=?g? _a_: arch-trees
_w_: ?w? week       _[_: inactive      _A_: arch-files
_t_: ?t? fortnight  _f_: follow=?f?    _r_: report=?r?
_m_: ?m? month      _e_: entry =?e?    _D_: diary=?D?
_y_: ?y? year       _q_: quit          _L__l__c_: ?l?

Doesn't that look simple?