Re: writing ledger mode, date picker

[jenia.ivlev]

Hello Emanuel. 

I'm trying to write a program that will prompt the user for a
date and insert it into a buffer called "asti" ;)

I'm having some success but also some problems. My problem, I think, is
that I'm using the `(when...)` function wrong. 

Here is the newest iteration of the program:

    (defun insert-new-entry ()
    (interactive)
    (save-excursion
        (goto-char (point-max))
        (print "Asti")
        (define-key calendar-mode-map (kbd "RET") 'get-date)
        (calendar)
        (when (calendar-cursor-to-date)
        (let ((x (calendar-cursor-to-date)))
            (select-window (get-buffer-window "asti" t))

                (insert format-time-string "%Y-%m-%d" x)))))


    (defun get-date ()
    (interactive)
    calendar-cursor-to-date)

The interpreter tells me, though, that `x` is nil basically: "Symbol's
value as a variable is void: format-time-string"

How do I execute this part AFTER the user has pressed "RET". 

    (let ((x (calendar-cursor-to-date))) <---- execute after "RET" pressed
        (select-window (get-buffer-window "asti" t))
            (insert format-time-string "%Y-%m-%d" x)))))

Thanks

P.S. To try my prog out, you need to open a buffer called asti by
doing `C-b 4 asti`.