14 righe
521 B
TeX
14 righe
521 B
TeX
\ifger{Jetzt wollen wir uns unsere Funktionen}{So how do our} \hinline{sum}, \hinline{prod} \ifger{und}{and} \hinline{length} \ifger{anschauen, wenn wir sie mittels \hinline{fold} implementieren:}{functions look like if we use our \hinline{fold} abstraction?}
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\pause
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\begin{haskellcode}
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sum :: [Int] -> Int
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sum xs = fold (\x y -> x + y) 0 xs
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-- a Haskeller would write
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sum = fold (+) 0
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prod :: [Int] -> Int
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prod xs = fold (\x y -> x * y) 1 xs
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length :: [a] -> Int
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length xs = fold (\x y -> 1 + y) 0 xs
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\end{haskellcode} |