Add list article (#35018)

guide/english/haskell/lists/index.md

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+---
+title: Lists
+---
+
+Lists are a widely used datatype in Haskell. In fact, if you have used strings you've used Haskell's lists!
+
+# Definition
+Haskell's lists are recursively defined as follows:
+
+```haskell
+data [] a     -- A List containing type `a`
+  = []        -- Empty list constructor.
+  | a : [a]   -- "Construction" constructor, a.k.a. cons.
+```
+
+Notice that lists in Haskell are not arrays, but linked lists.
+
+The following are examples of lists:
+
+```haskell
+empty :: [()]
+empty = []
+
+ints :: [Int]
+ints = 1 : 2 : 3 : []
+```
+
+There's syntactic sugar for making lists as well:
+
+```haskell
+bools :: [Bool]
+bools = [True, False, False, True]  -- True : False : False : True : []
+```
+
+`String` is just an alias for `[Char]`!
+
+```haskell
+chars :: [Char]
+chars = "This is a character list!"
+```
+
+# Functions
+Lists have many different built in functions. Here's a few:
+
+```haskell
+-- Concatenation:
+-- Stick two lists together.
+greeting :: String
+greeting = "Hello, " ++ "World!"    -- "Hello, World!"
+
+-- Map:
+-- Appy some function to overy element.
+abc :: [Int]
+abc = map succ [0, 1, 2]            -- [1, 2, 3]
+```
+
+# Pattern matching
+You can easily pattern match lists to easily recurse over them.
+
+```haskell
+map' :: (a -> b) -> [a] -> [b]
+map' _ [] = []                        -- Base case.
+map' f (a:as) = f a : map' f as       -- Recursive case.
+```