Re: writing ledger mode, date picker

[Emanuel Berg <embe8573@student.uu.se>]

jenia.ivlev@gmail.com (jenia.ivlev) writes:

> (defun insert-new-entry ()
>    (interactive)
>       (goto-char (point-max))
>       (define-key calendar-mode-map "\r" 'get-date)
>       (calendar))

That function first moves point to the end of the
buffer, than changes the key-map for the calendar
mode, then brings up the calendar.

1. Why is that called "insert-new-entry"?

2. Why move point? That happens *before* `calendar' is
   invoked. Remember your function can be called from
   anywhere in Emacs, i.e. from all modes and all
   buffers. Why move point in any and all of those?

3. If you want to change the key-map for a mode, don't
   do that in a defun. Just put this

       (require 'calendar)
       (define-key calendar-mode-map "\r" #'get-date)

    in an initiation file, i.e. most often ~/.emacs or
    some other file that is `load'ed from ~/.emacs.

Also, at least according to my Lisp-vision, there
shouldn't be indentation after the (interactive) line.
That is, the `goto-char' line should be align on the
same vertical level as the `interactive' line.

> (defun get-date ()
> (interactive)
>     (let* ((x (calendar-cursor-to-date))
>            (time (encode-time 0 0 0 (nth 1 x) (nth 0 x) (nth 2 x))))
>           (select-window (get-buffer-window "asti" t))
>           (insert (format-time-string "%Y-%m-%d" time))))

Even with the `encode-time' I still only get 1970s
dates! But if time works for you, still, check out
a previous post and the function I provided.

Some hints:

1. Be more pedantic with indentation!
   Use `indent-for-tab-command' (TAB) in the
   `emacs-lisp-mode' and let it be done for you.

2. Think of better names than `x'.

3. Instead of (nth 0 x), you can use `car'.

> P.S. This assumes you have an "asti" buffer opened
> (C-x 4 b asti).

Use `get-buffer-create' which will "[r]eturn the
buffer specified ... creating a new one if needed.
..." (from the help). get-buffer-create is what I used
in the function in my previous post, and that will
work regardless so you don't have to assume anything.

-- 
underground experts united
http://user.it.uu.se/~embe8573