Re: [Haskell-cafe] RebindableSyntax on individual do blocks

Here's a pretty elegant (read: hacky?) way of working with RebindableSyntax: === Foo.hs module Foo where import Prelude hiding (Monad (..)) import qualified Prelude as P data MyMonad m a b = MyMonad { (>>=) :: m a -> (a -> m b) -> m b , (>>) :: m a -> m b -> m b , return :: a -> m a , fail :: String -> m a } ioMonad :: MyMonad IO a b ioMonad = MyMonad (P.>>=) (P.>>) P.return P.fail === Bar.hs {-# OPTIONS -fno-warn-name-shadowing #-} {-# LANGUAGE RecordWildCards #-} {-# LANGUAGE RebindableSyntax #-} module Bar where import Prelude import qualified Foo normalDo :: Monad m => m () normalDo = do return () -- Inferred: ioDo :: IO () ioDo = do return () where Foo.MyMonad{..} = Foo.ioMonad Cheers, Adam On Mon, Jun 22, 2015 at 9:19 PM, Mark Roberts wrote:

Ah, I missed that bit. Thank you! Mark

On Mon, Jun 22, 2015 at 12:18 PM, Erik Hesselink wrote:

...

Hi Mark,

RebindableSyntax uses whatever (>>), (>>=) and return are in scope. So if you bind them in a `let` or `where`, you should be able to use different ones for different do blocks.

Erik

On Mon, Jun 22, 2015 at 8:39 PM, Mark Roberts wrote:

...

I have a program that uses both monads and indexed monads, and I'd like to use do-notation for each in the same source file. Is there a way to rebind syntax for only the do blocks that make use of an indexed monad?

Thanks, Mark

_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe

_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe