jutememo

import java.util.Arrays;
import java.util.List;

/**
 * 検索クラス
 */
public class Search {

    private static List<Person> persons = Arrays.asList(
            new Person("Tarou", "Tokyo"),

jutememo

import java.util.Arrays;
import java.util.List;

/**
 * 検索クラス
 */
public class Search {

    private static List<Person> persons = Arrays.asList(
            new Person("Tarou", "Tokyo"),

jutememo

import java.util.Arrays;
import java.util.List;

/**
* 検索クラス
*/
public class Search {

    private static List<Person> persons = Arrays.asList(
            new Person("Tarou", "Tokyo"),

jutememo

import Data.List

data Person = Person { name, address :: String} deriving Show

ps = [ Person "Tarou" "Tokyo"
     , Person "Jirou" "Osaka"
     , Person "Saburou" "Nagoya"
     ]

getAddress n ps = case find ((== n) . name) ps of

jutememo

module Counter where

-- カウンタを表わす型
data Counter a = Counter { val       -- 値
                         , step :: a -- 増分
                         } deriving Show

-- カウンタの値を増加させる
next :: Num a => Counter a -> (a, Counter a)
next (Counter v s) = let v' = v + s

jutememo

module State (State, comb, comb_, ret) where

type State s a = s -> (a, s)

comb :: State s a -> (a -> State s b) -> State s b
comb m n = \s0 -> let (x1, s1) = m s0
                      (x2, s2) = n x1 s1
                  in  (x2, s2)

comb_ :: State s a -> State s b -> State s b

jutememo

module Counter where

-- カウンタを表わす型
data Counter a = Counter { val       -- 値
                         , step :: a -- 増分
                         } deriving Show

-- カウンタの値を増加させる
next :: Num a => Counter a -> (a, Counter a)
next (Counter v s) = let v' = v + s

jutememo

module Stack(Stack, empty, empty', pop, push, push') where
 
newtype Stack a = Stack [a] deriving Show
 
empty :: Stack a
empty = Stack []
 
empty' :: Stack a -> ((), Stack a)
empty' _ = ((), Stack [])
 

jutememo

module Main where
import State
import Counter
import Stack

next3 = next `comb_` next `comb_` next
push3 = push' 100 `comb_` push' 200 `comb_` push' 300

counter = Counter 0 1
stack   = push 5 $ push 4 $ push 3 $ push 2 $ push 1 empty

jutememo

class Boolean b where
    isTrue :: b -> Bool

instance Boolean Bool where
    isTrue True  = True
    isTrue False = False

instance Boolean Integer where
    isTrue 0 = False
    isTrue _ = True