Help writing a helm email-address-at-point fn

[Tory S. Anderson]

I use helm and bbdb to complete addresses in my to/from/cc fields. It sort-of 
works, but I'm leveraging word-at-point. This means that if I type "Joe" and 
type "<TAB>", I see the completions I expect, but if I type "Joe Somebod" I get 
completions (and replace) just the "Somebod", both not taking into account the 
"Joe" and also leaving it there after I make my selection. It seems like I need 
to define a new "thing-at-point" function, but I'm having trouble figuring out 
how.

Looking at how bbdb-company isolates the right match, I gleaned the following 
regexp:

--8<---------------cut here---------------start------------->8---
(looking-back "^\\(To\\|Cc\\|Bcc\\): *.*? *\\([^,;]*\\)" 
(line-beginning-position))
--8<---------------cut here---------------end--------------->8---

But I can't quite figure out how to use that to make a thing-at-point I could 
drop in to replace my use of `word-at-point`. Any help would be much 
appreciated.

- Tory