35 lines
909 B
Haskell
35 lines
909 B
Haskell
-- SPDX-FileCopyrightText: 2022 Gregor Kleen <gregor.kleen@ifi.lmu.de>
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--
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-- SPDX-License-Identifier: AGPL-3.0-or-later
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{-# OPTIONS_GHC -fno-warn-orphans #-}
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module Data.Bool.Instances
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() where
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import ClassyPrelude
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import qualified Data.Csv as Csv
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import Data.CaseInsensitive (CI)
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import qualified Data.CaseInsensitive as CI
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import Data.CaseInsensitive.Instances ()
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import qualified Data.Text as Text
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import Control.Monad.Fail
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instance Csv.ToField Bool where
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toField True = "t"
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toField False = "f"
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instance Csv.FromField Bool where
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parseField f = do
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(CI.map Text.strip -> t :: CI Text) <- Csv.parseField f
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(True <$ guard (isTrue t)) <|> (False <$ guard (isFalse t)) <|> fail "Could not decode Bool"
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where
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isTrue = flip elem
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[ "yes", "y", "ja", "j", "wahr", "w", "true", "t", "1" ]
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isFalse = flip elem
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[ "no", "n", "nein", "falsch", "f", "false", "0" ]
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