LucianU/fromIndex.hs

Last active August 9, 2018 10:50

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fromIndex.hs

	fromIndex :: Int -> [a] -> Maybe a
	fromIndex 0 (x:xs) =
	Just x
	fromIndex index [] =
	Nothing
	fromIndex index (x:xs) =
	fromIndex (index - 1) xs

sshine commented Aug 9, 2018 •

edited

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You don't need the [x] special case. (This doesn't work as a base case, since [] is not caught. Use [] instead.)
Your fromIndex' is only necessary to keep track of currIndex, but you could use index recursively and subtract from it.

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