I just start ghci from shell and do nothing else. In fact, i really donot know `Monad ((->) a) ` . Would you mind expplain it ?
Yusaku Hashimoto wrote: > > Did you import the module includes the instance of Monad ((->) e) > somewhere in your code loaded in ghci? > > I tried this on a fresh ghci 6.12, but I got "No instance" error. > > -nwn > > On Sat, Mar 27, 2010 at 9:20 AM, zaxis <[email protected]> wrote: >> >> In 6.12.1 under archlinux >>>let f x y z = x + y + z >>> :t f >> f :: (Num a) => a -> a -> a -> a >> >>> :t (>>=) . f >> (>>=) . f :: (Num a) => a -> ((a -> a) -> a -> b) -> a -> b >>> ((>>=) . f) 1 (\f x -> f x) 2 >> 5 >> >> In 6.10.4_1 under freebsd >>> let f x y z = x + y + z >> *Money> :t f >> f :: (Num a) => a -> a -> a -> a >> >>> :t (>>=) . f >> (>>=) . f :: (Monad ((->) a), Num a) => a -> ((a -> a) -> a -> b) -> a >> -> b >>> ((>>=) . f) 1 (\f x -> f x) 2 >> >> <interactive>:1:1: >> No instance for (Monad ((->) a)) >> arising from a use of `>>=' at <interactive>:1:1-5 >> Possible fix: add an instance declaration for (Monad ((->) a)) >> In the first argument of `(.)', namely `(>>=)' >> In the expression: ((>>=) . f) 1 (\ f x -> f x) 2 >> In the definition of `it': it = ((>>=) . f) 1 (\ f x -> f x) 2 >> >> Sincerely! >> >> >> ----- >> fac n = let { f = foldr (*) 1 [1..n] } in f >> -- >> View this message in context: >> http://old.nabble.com/Why-is-it-so-different-between-6.12.1-and-6.10.4_1---tp28049329p28049329.html >> Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com. >> >> _______________________________________________ >> Haskell-Cafe mailing list >> [email protected] >> http://www.haskell.org/mailman/listinfo/haskell-cafe >> > _______________________________________________ > Haskell-Cafe mailing list > [email protected] > http://www.haskell.org/mailman/listinfo/haskell-cafe > > ----- fac n = let { f = foldr (*) 1 [1..n] } in f -- View this message in context: http://old.nabble.com/Why-is-it-so-different-between-6.12.1-and-6.10.4_1---tp28049329p28050535.html Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com. _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
