On Mon, Jan 6, 2014 at 10:15 PM, Courtney Robinson <courtney@crlog.info> wrote:

On Tue, Jan 7, 2014 at 3:03 AM, Brandon Allbery <allbery.b@gmail.com> wrote:

behind

Oh I see, thanks for the info. really helpful.

It brings about another question now.

How is newIORef meant to be used so that I only have a single IORef?

The Haskell way is to carry such things implicitly in a State or Reader monad; since the IORef itself doesn't change, and you need the IO monad around anyway to actually use it, you would use a ReaderT IORef IO and then use ask >>= liftIO . readIORef to get the value and similar to write or modify it. (Commonly one uses a type or newtype+newtype deriving to make one's own monad combining them.)

--

brandon s allbery kf8nh                               sine nomine associates

allbery.b@gmail.com                                  ballbery@sinenomine.net

unix, openafs, kerberos, infrastructure, xmonad        http://sinenomine.net

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