Improve function composition slides

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Julian Ospald 2015-04-19 17:54:25 +02:00
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@ -366,6 +366,15 @@ Solution:
(.) :: (b -> c) -> (a -> b) -> a -> c (.) :: (b -> c) -> (a -> b) -> a -> c
(.) f g x = f (g x) (.) f g x = f (g x)
\end{haskellcode} \end{haskellcode}
\pause
And now you can chain functions together. Not just two! Look:
\begin{haskellcode}
f :: String -> Bool
f xs = (even . length . (\x -> x ++ "Hello world")) xs
-- or less ugly
f xs = even . length . (\x -> x ++ "Hello world") $ xs
\end{haskellcode}
% $
\end{frame} \end{frame}
\section{6. Recursion patterns} \section{6. Recursion patterns}