Re: Improving Emacs' iCalendar support

[Björn Bidar]

Good Morning from Finland,

Richard Lawrence <rwl@recursewithless.net> writes:

> Dear emacs-devel,
>
> Hello! I've been a happy Emacs user for almost twenty years now(!), but
> this is my first time subscribing to this list, so please help me follow
> the local conventions.
>
> I would like to start a discussion about improving Emacs' iCalendar
> support, beyond what is already available in icalendar.el. I personally
> would like to see Emacs gain a more full-fledged RFC5545 implementation
> that is primarily designed as a library for other applications to use.
>
> This is an itch that's been bugging me for a while, and so for the past
> couple of weeks I've been working on scratching it, and I now have a
> reasonable chunk of work to share: I've drafted a new implementation of
> the iCalendar grammar, and a major mode which uses this grammar to
> provide syntax highlighting. I wrote up what I've done and why here:
>
> https://recursewithless.net/emacs/icalendar-parser-and-mode.org
>
> That's a literate Org mode file containing the code and my commentary.
> If you just want to read the code itself, see:
>
> https://recursewithless.net/emacs/icalendar/icalendar-parser.el
> https://recursewithless.net/emacs/icalendar/icalendar-mode.el
>
> I could release this work as a package, but as I describe in more
> detail in the write-up, I think there's a good case that an improved
> iCalendar library belongs in Emacs' core. There are currently at least
> *three* partial iCalendar implementations in Emacs (icalendar.el,
> gnus-icalendar.el, and ox-icalendar.el), which are each focused on a
> particular major mode (diary, Gnus, and Org). I think it would be good
> to consolidate this work in one place and generalize it so that all
> three of these applications, as well as third party packages, can
> benefit.

>From my dealings will the latter two I noticed that currently these
separatism make it harder to support all features and maybe in some way
easier.

For example Gnus does deal with the responding to these invitations
while org focuses on the exporting. Not all features are support with
any of these making some things such as recurring events quite dangerous
to deal with if you interact with others.

It would be great to have these features supported better. In think
some limitations in for example org-mode come also into play here as
last time I looked it can't deal with timezones.

Some parts of the current approach limit the amount of features or make
it harder as all of these move on.
For example Gnus uses org-capture to convert an icalendar
event to org instead of some form of native API to synchronize the
invite with-org.

Any advancement in regards of icalendar hopefully also helps the
other related formats such as vtodo and vcard.

Maybe also cc the org-mode mailing-list.

Another consumer of such efforts would be also (indirectly) org-caldav.
When it comes to the -dav part of this than also bbdb.

Have a good day,

Björn