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This function checks if a list is sorted. isSorted' :: (Ord a) => [a] -> [a] -> a -> Bool isSorted' [] [] _ = True isSorted' (x:xs) [] _ = isSorted' xs xs (head xs) isSorted' orig (x:xs) a | a > x …

Per Learn You a Haskell, I implemented a simple command-line program, Todo, that accepts 1 of 3 arguments: view or add or delete. … Please review my code for Haskell idioms & overall quality. -- view, add and delete tasks -- borrows delete from previous LYAH exercise import System.Environment import System.Directory import System.IO …

Please evaluate this function. It takes a list [a] and an Int, i.e. the index, and returns a new list with the selected item at the top of the list. Note that it returns Maybe [a] to account for bad i …

I wrote this code to append Maybe's: ghci> (:) <$> Just 5 <*> ((:) <$> Just 100 <*> Just []) Just [5,100] Similarly: ghci> (:) <$> Just 5 <*> ( (:) <$> Just 10 <*> ((:) <$> Just 100 <*> Just []) ) …

Given the Free Monad, and my Eq, Show, and Functor instances, I attempted to verify the first Functor law using QuickCheck: data Free f a = Var a | Node (f (Free f a)) I defined the …

Is the above code idiomatic in Haskell? …

I wrote the following split function. It takes a list, an element and an Ordering (LT, GT, EQ). For LT, the list will filter out all items that are >= the element argument. split' :: (Ord a) => [a] - …

I wrote a function that inserts or updates a Map key value depending on whether the key is already in the map. If it is, then the value gets added to the already existing map's value. import Data.Map …

Learn You a Haskell presents an excellent introduction to >>= with an example. …

Looking at Learn You a Haskell, I implemented a function that, given a binary tree, i.e. left and right branches, give a list of Directions and give the element at that location. …

The following function finds all local maxima. A local maxima is an element of a list such that it's greater than either of its neighbor elements. An element with 1 neighbor is not a local maximum. …

I wrote a function, doSkip. For an N-sized list, an element at index 0 consists of the entire input. Index 1 consists of every other element, i.e. the odd elements. Then, indexes 2 to N consist of th …

I attempted to implement a Monoid' instance for a function a -> b. class Monoid' a where mempty :: a -> a mappend :: a -> a -> a instance Monoid' (a -> b) where mempty f = f mapp …

Per this homework, I'm trying to implement a Fractional (Stream Integer) where the stream represents coefficients of polynomials: where Q is defined as Q = (A'/b0) + x((1/b0)(A' − QB0)). wher …

Related to this question, I wrote the (+++) function to join 2 JoinList's: (+++) :: Monoid m => JoinList m a -> JoinList m a -> JoinList m a (+++) Empty y = y (+++) x …