[Remind-Fans] Computing a priority

[Jens Mueller]

Hi,

I hope this is simple and I just didn't find it when searching list's
archive.
Suppose I have
rem 10 jan 2011 *1 +14 msg [magic_function()] Do this %a
rem 2 feb 2011 *1 +14 msg [magic_function()] Do that %a

magic_function should compute the difference between the date given in
the rem command and now in days. I want to use this field as a priority
field for sorting. So for the above I'd like to get
-21 Do this today
2 Do that on Wednesday, 2 February, 2011

Jens