tarquin-the-brave

tarquin-the-brave / maybefoldtype.hs

Created May 12, 2020 12:34

example from https://tarquin-the-brave.github.io/blog/posts/re-learning-haskell/

foldable t => (a -> a -> a) -> t a -> Maybe a

tarquin-the-brave / foresttype.hs

Created May 12, 2020 12:36

example from https://tarquin-the-brave.github.io/blog/posts/re-learning-haskell/

type Forest a = [Tree a]

tarquin-the-brave / unfoldforesttype.hs

Created May 12, 2020 12:37

example from https://tarquin-the-brave.github.io/blog/posts/re-learning-haskell/

unfoldForest :: (b -> (a, [b])) -> [b] -> Forest a

tarquin-the-brave / parseorbittype.hs

Created May 12, 2020 12:38

example from https://tarquin-the-brave.github.io/blog/posts/re-learning-haskell/

parseOrbit :: String -> (String, String)

tarquin-the-brave / findroots.hs

Created May 12, 2020 12:41

example from https://tarquin-the-brave.github.io/blog/posts/re-learning-haskell/

	-- Which bodies do not orbit anything?
	roots :: Eq a => [(a,a)] -> [a]
	roots orbits = [x \| (x, y) <- orbits, notElem x . fmap snd $ orbits]

tarquin-the-brave / forestbuilder.hs

Created May 12, 2020 12:41

example from https://tarquin-the-brave.github.io/blog/posts/re-learning-haskell/

	-- Given the orbit data, what orbits a given body?
	forestBuilder :: Eq a => [(a,a)] -> a -> (a,[a])
	forestBuilder orbits body = (body, [snd orbit \| orbit <- orbits, body == fst orbit])

tarquin-the-brave / unfoldfunction.hs

Last active May 12, 2020 12:42

example from https://tarquin-the-brave.github.io/blog/posts/re-learning-haskell/

	orbits :: [(String, String)]

	unfoldFunction :: String -> (String, [String])
	unfoldFunction = forestBuilder orbits

tarquin-the-brave / main.hs

Created May 12, 2020 12:43

example from https://tarquin-the-brave.github.io/blog/posts/re-learning-haskell/

	main = do
	contents <- fmap lines . readFile $ "input.txt"
	let orbits = fmap parseOrbit contents
	let myForest = unfoldForest (forestBuilder orbits) (roots orbits)

tarquin-the-brave / foldtreetype.hs

Created May 12, 2020 12:43

example from https://tarquin-the-brave.github.io/blog/posts/re-learning-haskell/

foldTree :: (a -> [b] -> b) -> Tree a -> b

tarquin-the-brave / dumdepths.hs

Created May 12, 2020 12:44

example from https://tarquin-the-brave.github.io/blog/posts/re-learning-haskell/

	levels :: Tree a -> [[a]]

	sumDepthsTree :: Integral b => Tree a -> b
	sumDepthsTree = snd . foldl foldFunc (0, 0) . levels

	foldFunc :: Integral a => (a,a) -> [b] -> (a,a)
	foldFunc (depth, acc) x = (depth + 1, acc + depth * genericLength x)