I use the emacs diary a lot, and have recently had to start using
several centralised online calendars, which provide ical feeds (for
work). It's on the todo list in icalendar.el (line 92) to allow
including these in the diary in the same manner as including other
files.

I had a look at implementing this, and it doesn't seem terribly
difficult. The problem is that all the functions for importing ical
data to the diary format (which is what the calendar, the diary and
org-mode all understand) write it to a file by default. So to include
a feed, one has to retrieve the feed into a buffer, import the current
(ical) buffer into a diary file, then include the diary file. This
works, but it seems expensive to write to disk only in order to
(immediately!) read again. It seems to me that it would be easier to
just import the data into a buffer and keep it there. Does anyone if
there was an original reason /not/ to do this?

Given an answer either way, I'll try to work up a patch with the right
method.

Blue skies, Hugo