スタートHaskell 第5回資料

1. 10
ruicc.rail@gmail.com

2. (Ruichi Kousuke)
@ruicc
http://d.hatena.ne.jp/ruicc

3. Haskell

4. 10
!!

5. Haskell Advent Calendar
Haskell Advent Calender
2
http://partake.in/events/eaea52c2-61ef-46d5-
a855-3a2dde459e3a

6. Haskell Advent Calendar2011 2
ruicc.rail@gmail.com

7. A Haskell
B
A
B
A ...

8. (OO)
(OO) (Haskell)
(Haskell)
10

9. (OO) (Haskell)
(OO) (Haskell)

12. (OO)
= +

13. (OO)
= +

14. (OO) (Haskell)
(OO) (Haskell)
Haskell

17. (Algebraic Data Type)
(Set)

18. Tuple ( )

19. or
Bool
True or False

21. data
data IntOrSome a = MkInt Int
| MkA a

22. data
data IntOrSome a = MkInt Int
| MkA a
(OO )

23. data type
data IntOrSome a = MkInt Int
| MkA a
type IntOrStr = IntOrSome String

24. ( )
add :: Int -> Int -> Int
add a b = a + b

26. (OO)
class IntAndStr {
private Int field1;
private String field2;
public IntAndStr (Int i, String s) {
field1 = i; field2 = s;
}
}
a = new IntAndStr(42, “aiueo”);

27. Haskell
data IntAndStr = MkIS Int String
let a = MkIS 42 “aiueo”

28. (OO)

29. Haskell
data Bool = False | True
data Maybe a = Nothing | Just a
data Either a b = Left a | Right b

30. (OO)

31. Haskell
data List a = Nil | Cons a (List a)
data Tree a = Leaf a
| Node (Tree a) (Tree a)

32. (OO) ..

33. FAQ
Q: Haskell private
A1: Python dis
A2: Javascript ( )

34. Haskell private( )
Haskell private
module

35. Haskell private:
where
module

36. OOP
(OO)

37. :Haskell

38. Y

39. (OO)
= +

42. ( )
( )

43. Haskell

45. FAQ
C++ Python
Y
Y Haskell

46. Haskell ( )
C++,Python
C++ :
Python : C3

47. FAQ
Scala Trait
scalaz Trait
Haskell

48. class
built-in Eq
class Eq a where
(==), (/=) :: a -> a -> Bool

49. class
class Eq a where
(==), (/=) :: a -> a -> Bool

50. class instance
class instance
Eq
class Eq a where
(==), (/=) :: a -> a -> Bool
MyType
instance Eq MyType where
x == y = ...
-- (==) :: MyType -> MyType -> Bool

51. class
Eq
class (Eq a) => Ord a where
(<=) :: a -> a -> Bool Ord
...

52. class
class (Eq a, Show a) => Num a where
(+) :: a -> a -> a
...
Show Eq
Num

53. Read
Show
instance
Typeable
Bounded Ix
Enum Data
Ord Eq
instance
MyType

54. deriving
data deriving
data MyType a b c = A a | B b | C c
deriving (Eq, Ord, Show, Read)
Read
Show
Ord Eq
MyType

55. deriving FAQ
URL: http://www.haskell.org/ghc/docs/7.2.2/html/
users_guide/deriving.html

56. Haskell
Haskell

57. instance Eq (Maybe Int)
:: *
instance Monad Maybe
:: * -> *

58. Monad, Functor, Applicative