In trying to follow along with `Programming with Arrows' by John
Hughes, I'm entering the following code:
1 -- Taken from `Programming with Arrows'.
2
3 module SF where
4
5 import Control.Arrow
6
7 newtype SF a b = SF {runSF :: [a] -> [b]}
8
9 instance Arrow SF where
10 arr f = SF (map f)
11 SF f >>> SF g = SF (f >>> g)
and getting the following error from GHCI:
GHCi, version 7.0.3: http://www.haskell.org/ghc/ :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
Prelude> :load SF
[1 of 1] Compiling SF ( SF.hs, interpreted )
SF.hs:11:10: `>>>' is not a (visible) method of class `Arrow'
Failed, modules loaded: none.
Can anyone help?
Thanks,
-db
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