[Haskell-cafe] Fighting the monad stack, MonadIO
Luke Palmer
lrpalmer at gmail.com
Thu Apr 10 15:42:35 EDT 2008
On Thu, Apr 10, 2008 at 2:50 PM, Adam Smyczek <adam.smyczek at gmail.com> wrote:
> For a small webapi binding I try to implement a session like monad
> by building a stack including BrowserAction from Network.Browser
> module as following:
>
> newtype RBAction a = RBAction
> { exec :: ErrorT String (StateT RBState BrowserAction) a }
> deriving (Functor, Monad, MonadState RBState)
>
> I would like the RBAction to implement MonadIO as well,
> but fight with the liftIO function for hours now, without success.
> Any idea how the implementation of liftIO could look like?
I suspect BrowserAction does not implement MonadIO (lest you could
just put MonadIO in the deriving clause). So, that depends on how
BrowserAction is implemented. What package is Network.Browser in?
Luke
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