General advice - incorporating gmail IMAP

[Harry Putnam]

I'm a little lost at the start, trying to decide how to incorporate
gmail IMAP access into my existing setup:

  Setup for mail:

fetchmal & sendmail are running on localhost (A single user home
machine)  => 

 fetchmail  pulls from pop servers
  fetchmail passes that data to sendmail
   sendmail delivers thru procmail to a mail spool directory with mail
            boxes notated like `somemail.in'

Gnus then knows to slurp from those mailboxes notated with `*.in' and
deliver to nnml mailboxes of the same name (minus the `.in' part)  

So my mail boxes are NNML.

I've used this setup for many years and have evolved an extensive
~/.procmail delivery file.  And a vast array of assorted nnml mail
boxes. 

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    Setup for NNTP:

I use the gmane NNTP server and a pay for NNTP server I've had
for years, newsguy (enews.newsguy.com accessed by way of an 
                    ~/.authinfo file)

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Now I'd like to add gmail using its IMAP server.

My aim is a bit more than just receiving mail that way.  I hope to be
able to subscribe to various google groups by mail and end up with
something sort of similar to nntp access to those groups.

Some topics today are not available via NNTP but have moved to the
much more awkward and less readable `web forum' type of access.

I'm hoping some of the google groups may be accessed by mail
subscription and then thru IMAP using gnus.

Reading from gnus thru IMAP, I'm guessing will be somewhat similar to
ease and quickness of NNTP access. 

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Getting back to the point of the post:  I'd like to be steered to
documentation that will help me integrate all this into my existing
setup described in the first couple paragraphs above.

I've never used gnus own nnimap backend.  Where I get confused is
trying to think how to integrate gmail IMAP into the existing setup.

gmail IMAP needs some particular kind of access and authentication all
described in googles documentation.

I found lots of information on the emacs gmail wiki:

  http://www.emacswiki.org/emacs/GnusGmail

And some description of using gmail IMAP at the URL below, written
by a guy running ubuntu: 
  
  http://ankurjain.in/blog/tag/emacs/

In both cases directions are quite different from my setup, so
integrating the two is the rub.