[Haskell-cafe] Re: Monad transformers

On Sun, 8 May 2005 20:29:31 +0200, Tomasz Zielonka said:

On Sun, May 08, 2005 at 10:19:28PM +0400, Max Vasin wrote:

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On Sun, 8 May 2005 18:34:37 +0200, Tomasz Zielonka said:

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On Sun, May 08, 2005 at 07:54:43PM +0400, Max Vasin wrote:

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f :: ReaderT env monad1 rtype g :: Reader env rtype

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How about: > toReaderT :: (Monad m) => Reader r a -> ReaderT r m a > toReaderT (Reader f) = ReaderT (return . f)

Thanks. toReaderT should be

toReaderT (Reader f) = ReaderT (return . (runReader f))

You can also make 'g' more generic, using the MonadReader type-class. So I should its type should be

g :: (MonadReader m) => m env rtype and than f = let r = g ? -- WBR, Max Vasin.