cedric's bazaar

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====== Presentation ======
===== Paradigm =====
  * purely-functional;
  * lazy evaluation.

===== Typing discipline =====
  * static typed;
  * strongly typed;
  * inferred.


====== Learning Haskell ======

  * [[http://www.haskell.org/ | The Haskell Programming Language]]


====== Simple examples ======

You can compare functions below with the [[cs_lang:ocaml#simple_examples | Objective Caml]] version.

===== Increment a number =====
<code haskell>
let inc = (+) n

-- Alternative:
let inc n = succ n
</code>


===== Caesar cipher =====

<code haskell>
-- Shifts a character to the right if positive, left if negative.
shift :: Int -> Char -> Char
shift n c | isUpper c = chr $ ord 'A' + ((ord c + n - ord 'A') `mod` 26)
          | isLower c = chr $ ord 'a' + ((ord c + n - ord 'a') `mod` 26)
          | otherwise = c


encode :: Int -> String -> String
encode _  [] = []
encode n  xs = map (shift n) xs
</code>


===== Parity =====
<code haskell>
parity :: Integral a => [a] -> [Bool]
-- Using recursion
parity [] = []
parity (x:list) = [even x] ++ parity list

-- Using map
parity list = map even list
</code>