rexcfnghk

class Category y where
    id  :: y a a                   -- identity for composition.
    (.) :: y b c -> y a b -> y a c -- associative composition.

rexcfnghk

instance Functor [] where
  fmap _ [] = []
  fmap f (x::xs) = f x :: fmap f xs

instance Functor Maybe where
  fmap _ Nothing = Nothing
  fmap f (Just x) = Just (f x)
  
instance Functor (Either a) where
  fmap _ x@(Left _) = x

rexcfnghk

public static List<int> Foo()
{
  var list = new[] { 1, 2, 3, 4, 5 };
  return list.Select(x => x).ToList();
}

rexcfnghk

import Data.Foldable

secondLargest :: (Ord a, Foldable t) => t a -> Maybe a
secondLargest = snd . foldl' secondLargest' (Nothing, Nothing) where
    secondLargest' (Nothing, Nothing) x = (Just x, Just x)
    secondLargest' (Just largest, Just second) x 
        | x > largest = (Just x, Just largest)
        | x > second  = (Just largest, Just x)
        | otherwise   = (Just largest, Just second)
    secondLargest' tuple _ = tuple

rexcfnghk

snd :: (a, b) -> b
snd (_, x) = x

rexcfnghk

import Data.Foldable

secondLargest :: (Num a, Ord a, Foldable t) => t a -> a
secondLargest xs = snd . foldl' secondLargest' (0, 0) xs where 
    secondLargest' (largest, second) x 
        | x > largest = (x, largest)
        | x > second = (largest, x)
        | otherwise = (largest, second)   

rexcfnghk

(.) :: (b -> c) -> (a -> b) -> a -> c
f . g = \x -> f (g x)

rexcfnghk

public static class Math
{
	public static T SecondLargest<T>(IEnumerable<T> inputs) where T : IComparable<T>
	{
		// Null checks skipped for brevity
		var (largest, second) = (default(T), default(T));
		foreach (var input in inputs)
		{
			if (input.CompareTo(largest) > 0)
			{

rexcfnghk

import Data.Foldable

secondLargest :: (Num a, Ord a, Foldable t) => t a -> a
secondLargest = snd . foldl' secondLargest' (0, 0) where 
    secondLargest' (largest, second) x 
        | x > largest = (x, largest)
        | x > second = (largest, x)
        | otherwise = (largest, second)   

rexcfnghk

isLeapYear :: Int -> Bool
isLeapYear year
  | isDivisibleBy 400 = True
  | isDivisibleBy 100 = False
  |   isDivisibleBy 4 = True
  |         otherwise = False
  where isDivisibleBy divisor = year `mod` divisor == 0