Jeff Polakow wrote:
Hello,
> 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.
Jules
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