[Haskell-cafe] Re: Is "take" behaving correctly?
jules at jellybean.co.uk
Thu Sep 13 09:02:15 EDT 2007
Jeff Polakow wrote:
> > There are 4 variants of tail:
> > tail :: [a] -> [a] -- normal
> > tailDef :: [a] -> [a] -> [a] -- returns the first argument on 
> > tailMay :: [a] -> Maybe [a] -- returns a Nothing
> > tailNote :: String -> [a] -> [a] -- crashes, but with a helpful message
> > tailSafe :: [a] -> [a] -- returns  on 
> Is there a reason for not having
> tailM :: Monad m => [a] -> m [a]
Monads are not an (elegant, or deliberate) abstraction of failure.
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