darcs - DrHylo

1 module Sample where

3 comp :: (b->c, a->b) -> (a->c)

4 comp (f,g) = f . g

6 swap :: (a,b) -> (b,a)

7 swap (x,y) = (y,x)

9 assocr :: ((a,b),c) -> (a,(b,c))

10 assocr ((x,y),z) = (x,(y,z))

12 distr :: (a, Either b c) -> Either (a,b) (a,c)

13 distr (x, Left y) = Left (x,y)

14 distr (x, Right y) = Right (x,y)

16 coswap :: Either a b -> Either b a

17 coswap (Left y) = Right y

18 coswap (Right y) = Left y

20 undistr :: Either (a,b) (a,c) -> (a, Either b c)

21 undistr (Left (y,z)) = (y, Left z)

22 undistr (Right (x,z)) = (x, Right z)

24 data Nat = Zero | Succ Nat deriving Show

26 plus :: (Nat, Nat) -> Nat

27 plus (Zero, z) = z

28 plus (Succ n, z) = Succ (plus (n,z))

30 mult :: (Nat, Nat) -> Nat

31 mult (Zero, x) = Zero

32 mult (Succ n, x) = plus (x, mult (n, x))

34 fact :: Nat -> Nat

35 fact Zero = Succ Zero

36 fact (Succ n) = mult (Succ n, fact n)

38 len :: [a] -> Nat

39 len [] = Zero

40 len (h:t) = Succ (len t)

42 fib :: Nat -> Nat

43 fib Zero = Succ Zero

44 fib (Succ Zero) = Succ Zero

45 fib (Succ (Succ x)) = plus (fib x, fib (Succ x))

47 cat :: [a] -> [a] -> [a]

48 cat [] l = l

49 cat (h:t) l = h : cat t l

51 data Tree a = Leaf | Node a (Tree a) (Tree a) deriving Show

53 inorder :: Tree a -> [a]

54 inorder Leaf = []

55 inorder (Node x l r) = cat (inorder l) (x : inorder r)