Haskell a la carte

Apéritifs

Foretaste of an excellent meal.

  qsort :: Ord a => [a] -> [a]
  qsort []     = []
  qsort (x:xs) = qsort (filter (<x) xs) ++ [x] ++ qsort (filter (>x) xs))

Quicksort in three lines (!). Sorts not only integers but anything that can be compared.

  fibs = 1:1:zipWith (+) fibs (tail fibs)

The infinite list of fibonacci numbers. Just don't try to print all of it.

  linecount = interact $ show . length . lines
  wordcount = interact $ show . length . words

Count the number of lines or words from standard input.

Entrées

How to eat?

  square x = x*x

The function $f(x)=x\cdot x$ which maps a number to its square. While we commonly write parenthesis around function arguments in mathematics and most programming languages, a simple space is enough in Haskell. We're going supply arguments all around, so why clutter the notation with unnecessary ballast?

Plats principaux

Desserts

Vins