Hi,

Consider the following (somewhat contrived) "fancy" splitting method:

  (nnimap-split-fancy
   (| ("cc" "\\(gnucash-user\\)@gnucash.org" "list.\\1")
      "INBOX"))

Consider also the attached example email (this is an email that was
recently sent to the public gnucash-user@gnucash.org list), which
contains the following header:

  Cc: gnucash-user <gnucash-user@gnucash.org>

When I put the above nnimap-split-fancy declaration into my nnimap
declaration in my ~/.gnus.el, how will Gnus split the example email?
Let's ask Gnus!  "M-x gnus-summary-respool-query" (B q) says:

  This message would go to list.gnucash-user

Also, "M-x gnus-summary-respool-trace" (B t) says:

  ("cc" "\\(gnucash-user\\)@gnucash.org" "list.\\1")
  "list.\\1"

OK, good.  That's what I expected.  Now let's change the declaration to
this:

  (nnimap-split-fancy
   (| ("cc" "\\(.*\\)@gnucash.org" "list.\\1")
      "INBOX"))

This is the same as before, but I've replaced "gnucash-user" with ".*".
I expected the same result as before, but Gnus surprised me.  Instead,
gnus-summary-respool-query says:

  This message would go to list.user

and gnus-summary-respool-trace says:

  ("cc" "\\(.*\\)@gnucash.org" "list.\\1")
  "list.\\1"

In this case, why does the ".*" match "user" instead of "gnucash-user"?
I've read the Gnus manual ((gnus) Splitting Mail, and similar sections).
I've read the elisp manual ((elisp) Regular Expressions).  I've even
experimented on the raw message headers using "M-x regexp-builder".  My
understanding is that "gnucash-user" is present in the string being
matched against, and that ".*" is a greedy regexp which matches any
character repeated zero or more times.  I don't understand how ".*" can
possibly match just the string "user".  What am I missing?

-- 
Chris