Diwali hacks

After quite a long time, I got some spare hours to hack on open source projects during this Diwali holidays. I added a helper function in persistent which in my opinion is super cool:

The liftSqlPersistMPool is simply defined like this:

liftSqlPersistMPool :: MonadIO m => SqlPersistM a -> Pool SqlBackend -> m a
liftSqlPersistMPool x pool = liftIO (runSqlPersistMPool x pool)

And this will help in converting code like this:

main :: IO ()
main = runStderrLoggingT $ withPostgresqlPool conn 10 $ \pool -> liftIO $ do
         flip runSqlPersistMPool pool $ do
           runMigration migrateAll

to:

main :: IO ()
in = runStderrLoggingT $ withPostgresqlPool conn 10 $ liftSqlPersistMPool $ do
         runMigration migrateAll

Ain’t that neat? :-)

The other patches for persistent included some cleanup, some documentation and a ownership related patch. Although, I plan to work on the ownership related code later. (See Issue 390 for more details.)

Also, I briefly hacked on the emacs haskell-mode package. Sent some minor patch related to hayoo and cleanup.

With respect to mathematics, I was not able to progress much besides reading some pages in Chapter 5. But I’m almost at the end of the chapter 5.