In the
On Saturday, May 10, 2014 2:01:04 AM UTC+2, Gabriel Gonzalez wrote:
>
> Sorry for the late response, but I was busy preparing for BayHac.
>
> I really loved Tony's `mvc`-based solution (of course I'm biased). The
> only thing I wanted to add was the following rule of thumb for how to get
> local vs global state.
>
> For local state, put the `StateT` layer outside the `Pipe` layer and then
> immediately run the `StateT` layer before composing it with other pipes:
>
> numbers :: Monad m => Producer Int m r
> numbers = flip evalStateT 0 $ forever $ do
> n <- get
> lift (yield n)
> put $! n + 1
>
For local state, I guess a loop might be as good, isn't ?
numbers :: Monad m => Int -> Producer Int m r
numbers = go
where
go n = do yield n; go $! n + 1
`PipeScore` for instance seems to be better expressed as such:
pipeScore :: (Monad m) => Board -> Pipe (Either String Int) (Either String
(Int,Board)) m ()
pipeScore = go
where
go b = do
for cat $ \x -> case x of
Left s -> yield (Left s)
Right n -> do
case score n b of
Right (a', b') -> do
yield (Right (a',b'))
if isGameOver b'
then yield (Left "Game over. Bye. See you
next time")
else go b'
Left msg -> do
yield (Left msg)
go b
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