Differences

This shows you the differences between two versions of the page.

--- cs_lang:haskell [2012/04/29 11:28] – created cedric
+++ cs_lang:haskell [2012/04/30 16:51] (current) – [Caeser cipher] cedric
@@ Line 1: / Line 1: @@
 ====== 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>