Once you get the basics, would you mind adding some basic IMAP support? IMHO that would be a killer feature, outside emacs there is simply so decent, scriptable MUA with IMAP support and while I've heard lots of complaints, there are unfortunately no recent initiatives to improve that situation (in contrast to offline clients like your luamail or e.g. sup or notmuch). Before you outright reject the idea, have a quick look at http://www.etpan.org/ and https://github.com/dinhviethoa/libetpan/blob/master/tests/imap-sample.c ;) it has a fairly clean API and sufficient abstraction to make it pleasant to work with (especially when comparing it to the crufty old c-client library).

I've seen a couple of IMAP libraries for Lua and while I don't want to disappoint I can't help but thinking that using IMAP will add a lot of complexity:

• Fetching folder lists which might change.
• Dealing with network logins + errors.
• Etc, etc.

I use two boxes, one delivers locally via procmail, the other locally via an Exim sieve filter. I figured I could cope with IMAP-users by just letting them run "imapsync" on_startup() and on_idle().

That seems like the simplest possible solution which will let them use the client and avoid me having to write the IMAP-code.

It is a bit aged but, in case you hadn't read about it, I thought I'll share a this link with you - http://dieter.plaetinck.be/luamail_a_mail_client_built_into_luakit.html

I understand that ideas are different here but you might find it a useful read and maybe even re-use some of the building blocks, i.e. luaimap.