Re: Diary sexp and comparing dates, agenda

[David Rogers <davidandrewrogers@gmail.com>]

Ihor Radchenko <yantar92@posteo.net> writes:

> You don't need diary-float - it returns true/false whether 
> current DATE
> fits the arguments.
>
> Instead, you can make use of `calendar-nth-named-absday'.
> For example,
>
> <%%(and (= 245 (mf-days-from-easter))
>         (< (calendar-absolute-from-gregorian date)
>            (calendar-nth-named-absday -4 0 12 24)))>
>
> Diary sexps are nothing but ordinary Elisp, with an extra twist 
> that
> during evaluation `date' variable is bound to current calendar 
> date.
> When they return nil, DATE does not match.


Thank you!

It seems that `calendar-nth-named-absday' wants the year after the 
month, and then an (optional) day of the month to count from. 
Since I hoped to keep re-using this material every year without 
re-entering the calculations, I've tried the following:

In my init file, I've added these two short definitions:

    (defun mf-beginning-of-advent (displayed-year)
      (calendar-nth-named-absday -4 0 12 displayed-year 24))

    (defun mf-days-from-advent ()
      (- (calendar-absolute-from-gregorian date) 
      (mf-beginning-of-advent (calendar-extract-year date))))

And my Org file has this:

* Example 1
<%%(and (= 245 (mf-days-from-easter)) (<= (mf-days-from-advent) 
-1))>


This setup seems to work so far. Does it look reasonable to you?

-- 
David