Sorry, it was just a persudo code. This might be more clear:
run :: (Monad m) => m IO a -> IO a
On Fri, May 4, 2012 at 4:32 PM, Yves Parès
run :: Monad IO a -> IO a
Actually this type is wrong. Monad has to appear as a class constraint, for instance :
run :: Monad m => m a -> IO a
Are you trying to make:
run :: IO a -> IO a ??
2012/5/4 Magicloud Magiclouds
Hi, Assuming this: run :: Monad IO a -> IO a data Test = Test { f }
Here I'd like to set f to run, like "Test run". Then what is the type of f? The confusing (me) part is that, the argument pass to f is not fixed on return type, like "f1 :: Monad IO ()", "f2 :: Monad IO Int". So "data Test a = Test { f :: Monad IO a -> IO a} does not work. -- 竹密岂妨流水过 山高哪阻野云飞
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