Of note, there is a sensible monad instance for zip lists which I *think* agrees with the Applicative one, I don't know why they're not monads:
instance Monad (ZipList a) where return = Ziplist . return join (ZipList []) = ZipList [] join (ZipList (a:as)) = zlHead a `zlCons` join (map zlTail as) I'll provide an alternative though, Const a is an applicative, but not a monad. Bob On Fri, Oct 30, 2009 at 5:25 PM, Eugene Kirpichov <[email protected]>wrote: > Yes. ZipList. > http://en.wikibooks.org/wiki/Haskell/Applicative_Functors > > 2009/10/30 Yusaku Hashimoto <[email protected]>: > > Hello cafe, > > Do you know any data-type which is Applicative but not Monad? > > > > Cheers, > > -~nwn > > _______________________________________________ > > Haskell-Cafe mailing list > > [email protected] > > http://www.haskell.org/mailman/listinfo/haskell-cafe > > > > > > -- > Eugene Kirpichov > Web IR developer, market.yandex.ru > _______________________________________________ > Haskell-Cafe mailing list > [email protected] > http://www.haskell.org/mailman/listinfo/haskell-cafe >
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