14 rader
388 B
TeX
14 rader
388 B
TeX
Let's abstract out the common pieces! This will be our type signature:
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\begin{haskellcode}
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filter :: (a -> Bool) -> [a] -> [a]
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\end{haskellcode}
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Solution?
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\pause
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\begin{haskellcode}
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filter :: (a -> Bool) -> [a] -> [a]
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filter f [] = []
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filter f (x:xs)
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| f x = x : filter f xs
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| otherwise = filter f xs
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\end{haskellcode}
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Again: this function is part of the \emph{Prelude} as well. |