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comparison delta.hs @ 82:1339772b2e36

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Define DeltaM. Delta with Monad
author Yasutaka Higa <e115763@ie.u-ryukyu.ac.jp>
date Sun, 04 Jan 2015 16:31:17 +0900
parents 0ad0ae7a3cbe
children 6635a513f81a
comparison
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81:47317adefa16 82:1339772b2e36
46 46
47 instance Monad Delta where 47 instance Monad Delta where
48 return x = Mono x 48 return x = Mono x
49 d >>= f = mu $ fmap f d 49 d >>= f = mu $ fmap f d
50 50
51
52
53 -- utils 51 -- utils
54 52
55 returnS :: (Show s) => s -> Delta s 53 returnS :: (Show s) => s -> Delta s
56 returnS x = Mono x 54 returnS x = Mono x
57 55
87 where 85 where
88 maximumValue = maximum xs 86 maximumValue = maximum xs
89 sortedValueL = maximumValue 87 sortedValueL = maximumValue
90 sortedValueR = replicate (length $ filter (== maximumValue) xs) maximumValue 88 sortedValueR = replicate (length $ filter (== maximumValue) xs) maximumValue
91 remainValue = filter (/= maximumValue) xs 89 remainValue = filter (/= maximumValue) xs
90
91 -- DeltaM Definition (Delta with Monad)
92
93 data DeltaM m a = DeltaM (Delta (m a)) deriving (Show)
94
95
96 -- DeltaM utils
97
98 headDeltaM :: DeltaM m a -> m a
99 headDeltaM (DeltaM (Mono x)) = x
100 headDeltaM (DeltaM (Delta x _ )) = x
101
102 tailDeltaM :: DeltaM m a -> DeltaM m a
103 tailDeltaM d@(DeltaM (Mono _)) = d
104 tailDeltaM (DeltaM (Delta _ d)) = DeltaM d
105
106 appendDeltaM :: DeltaM m a -> DeltaM m a -> DeltaM m a
107 appendDeltaM (DeltaM d) (DeltaM dd) = DeltaM (deltaAppend d dd)
108
109
110 -- DeltaM instance definitions
111
112 instance (Functor m) => Functor (DeltaM m) where
113 fmap f (DeltaM d) = DeltaM $ fmap (fmap f) d
114
115 instance (Applicative m) => Applicative (DeltaM m) where
116 pure f = DeltaM $ Mono $ pure f
117 (DeltaM (Mono f)) <*> (DeltaM (Mono x)) = DeltaM $ Mono $ f <*> x
118 df@(DeltaM (Mono f)) <*> (DeltaM (Delta x d)) = appendDeltaM (DeltaM $ Mono $ f <*> x) (df <*> (DeltaM d))
119 (DeltaM (Delta f df)) <*> dx@(DeltaM (Mono x)) = appendDeltaM (DeltaM $ Mono $ f <*> x) ((DeltaM df) <*> dx)
120 (DeltaM (Delta f df)) <*> (DeltaM (Delta x dx)) = appendDeltaM (DeltaM $ Mono $ f <*> x) ((DeltaM df) <*> (DeltaM dx))
121
122 instance (Monad m) => Monad (DeltaM m) where
123 return x = DeltaM $ Mono $ return x
124 (DeltaM (Mono x)) >>= f = DeltaM $ Mono $ (x >>= headDeltaM . f)
125 (DeltaM (Delta x d)) >>= f = appendDeltaM ((DeltaM $ Mono x) >>= f)
126 ((DeltaM d) >>= tailDeltaM . f)
127
128
129 -- DeltaM examples
130
131 val :: DeltaM [] Int
132 val = DeltaM $ deltaFromList [[10, 20], [1, 2, 3], [100,200,300], [0]]
133
134 func :: Int -> DeltaM [] Int
135 func x = DeltaM $ deltaFromList [[x+1, x+2, x+3],
136 [x*x],
137 [x, x, x, x]]