45 lines
1.0 KiB
Haskell
45 lines
1.0 KiB
Haskell
{-# LANGUAGE ScopedTypeVariables #-}
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{-# LANGUAGE StrictData #-}
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{-# LANGUAGE TemplateHaskell #-}
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module MaybeHelp where
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import Control.Lens
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import Data.Aeson
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import Data.Aeson.TH
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data Maybe' a = Just' {__Just' :: a} | Nothing'
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--deriving (Eq, Ord, Show, Read, Generic) --Generic, Flat)
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deriving (Eq, Ord, Show, Read) --Generic, Flat)
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--instance ToJSON a => ToJSON (Maybe' a) where
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-- toEncoding = genericToEncoding defaultOptions
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--
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--instance FromJSON a => FromJSON (Maybe' a)
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--maybe' :: b -> (a -> b) -> Maybe' a -> b
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fromJust' :: Maybe' a -> a
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fromJust' mx = case mx of
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Just' x -> x
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Nothing' -> error "no fromJust'"
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isJust' :: Maybe' a -> Bool
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isJust' Just'{} = True
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isJust' Nothing' = False
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isNothing' :: Maybe' a -> Bool
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isNothing' Just'{} = False
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isNothing' Nothing' = True
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strictify :: Maybe a -> Maybe' a
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strictify Nothing = Nothing'
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strictify (Just x) = Just' x
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toggleJust :: Maybe a -> Maybe ()
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toggleJust Nothing = Just ()
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toggleJust _ = Nothing
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makeLenses ''Maybe'
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deriveJSON defaultOptions ''Maybe'
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