>> `icalendar-export-sexp-enumeration-days' is set to 366 to guarantee >> that the sexp event occurs at least once. It looks like there's a >> different bug (?) where, even if an entry is recognized as an >> arbitrary diary sexp, if it doesn't produce any events, the converter >> will go ahead with trying to interpret it in a different way and >> eventually fail. E.g., lowering the enumeration days to 0 gives: >> >> "Error in line 0 -- (error Could not parse date): ‘%%(my-float 7 0 1) >> First Sunday in July 2’" >> >> after exhausting all of the known entry types. Should I file this as a >> separate bug? > > No, we can work on this problem here in this bug report. > > Do you have a recipe to reproduce the problem, starting from "emacs -Q"? Yep, you can use the same testing script and just replace the last expression with: (let ((icalendar-export-sexp-enumeration-days 0)) (test-diary-sexp "%%(diary-float 7 0 1) First Sunday in July 1") (test-diary-sexp "%%(my-float 7 0 1) First Sunday in July 2")) which should give you the error I mentioned. I don't have a patch for this on hand but it would probably require restructuring the surrounding code a little bit. There's another bug that concerns sexps that contain more than a single closing parenthesis. Seems like the icalendar code uses a bunch of regexes to parse the sexp (see `icalendar--convert-sexp-to-ical'), rather than something like `read' or `read-from-string' (which is what diary does, as well as org-agenda). To reproduce (with the same testing code as before): (let ((icalendar-export-sexp-enumeration-days 366)) (test-diary-sexp "%%(= (calendar-day-of-week date) 0) Sunday 1") (test-diary-sexp "%%(= 0 (calendar-day-of-week date)) Sunday 2")) No matter whether the closing parentheses are bunched together or separated, parsing fails either way. I've attached a draft of a patch that modifies as little as possible and makes the above two cases work, but that's not enough as there's special handling of `and' forms. Furthermore, sexps that span multiple lines fail for the same reason, even though diary handles them just fine of course. Ideally the whole function should be rewritten to just use `read-from-string'. I don't understand why `and' forms are handled specially though, so I'm not sure how to proceed here. A last thing to note -- even though org-agenda properly handles multiline sexps and sexps with an arbitrary number of closing parentheses (because it does the parsing manually and uses `forward-sexp'), Org's parser itself does not properly handle multiline sexps (but does handle multiple closing parentheses). To confirm, use `org-element-at-point' at the beginning of these two diary sexps in an org-mode buffer: %%(let ((a 123) (b 456)) (+ a b)) %%(let ((a 123) (b 456)) (+ a b)) All of these bugs also propagate to ox-icalendar (which is how I got into exploring this whole thing) since it relies on the Org parse tree to pull out 'diary-sexp elements and on icalendar to export them into iCalendar format. Let me know if you want me to report any of these as separate bugs and what would be the best thing to do here. Regards, hokomo