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cs_lang:haskell [2012/04/29 11:37] cedriccs_lang:haskell [2012/04/30 16:51] (current) – [Caeser cipher] cedric
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 ====== Presentation ====== ====== Presentation ======
 ===== Paradigm ===== ===== Paradigm =====
-  * functionneal +  * purely-functional; 
-  * lazy evaluation+  * lazy evaluation.
  
 ===== Typing discipline ===== ===== Typing discipline =====
-  * Unordered List Item 
   * static typed;   * static typed;
-  * strong types+  * strongly typed
-  * inferred; +  * inferred. 
-  * lazy evaluation;+
  
 ====== Learning Haskell ====== ====== 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>
cs_lang/haskell.1335692274.txt.gz · Last modified: 2012/04/29 11:37 by cedric