14 lines
376 B
TeX
14 lines
376 B
TeX
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So how do our \code{sum}, \code{prod} and \code{length} functions look like if we use our \code{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 0 (\x y -> x + y) 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 1 (\x y -> x * y) xs
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length :: [a] -> Int
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length xs = fold 0 (\x y -> 1 + y) xs
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\end{haskellcode}
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