39 lines
1.2 KiB
Haskell
39 lines
1.2 KiB
Haskell
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{- proposed and accepted values
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-
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- Copyright 2020 Joey Hess <id@joeyh.name>
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-
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- Licensed under the GNU AGPL version 3 or higher.
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-}
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module Types.ProposedAccepted where
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import Test.QuickCheck
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-- | A value that may be proposed, or accepted.
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--
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-- When parsing/validating the value, may want to error out on invalid
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-- input. But if a previous version of git-annex accepted an invalid value,
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-- it's too late to error out, and instead the bad value may be ignored.
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data ProposedAccepted t = Proposed t | Accepted t
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deriving (Show)
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fromProposedAccepted :: ProposedAccepted t -> t
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fromProposedAccepted (Proposed t) = t
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fromProposedAccepted (Accepted t) = t
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-- | Whether a value is proposed or accepted does not matter when checking
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-- equality.
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instance Eq t => Eq (ProposedAccepted t) where
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a == b = fromProposedAccepted a == fromProposedAccepted b
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-- | Order by the contained value, not by whether it's proposed or
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-- accepted.
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instance Ord t => Ord (ProposedAccepted t) where
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compare a b = compare (fromProposedAccepted a) (fromProposedAccepted b)
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instance Arbitrary t => Arbitrary (ProposedAccepted t) where
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arbitrary = oneof
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[ Proposed <$> arbitrary
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, Accepted <$> arbitrary
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]
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