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In Haskell, variables don't vary — once bound, a name can't be reassigned. There's no mutation in pure code (mutation requires IORef in IO).

name :: String
name = "Alice"

age :: Int
age = 30

-- Inside a function: let or where
greeting = let n = "Bob"
               a = 25
           in "Hi " ++ n

Basic types:

• Int, Integer (Integer is arbitrary-precision)
• Double, Float
• Bool (True / False)
• Char, String (which is [Char] — a list of characters)

Type signatures use ::. Function types use ->: add :: Int -> Int -> Int is "a function taking two Ints and returning an Int". (The -> is right-associative — really it's Int -> (Int -> Int) — but more on that later.)