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Gabriella439/Example.hs

Created December 5, 2022 23:19
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  1. Gabriella439 created this gist Dec 5, 2022.
    26 changes: 26 additions & 0 deletions Example.hs
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    {-# LANGUAGE AllowAmbiguousTypes #-}
    {-# LANGUAGE ScopedTypeVariables #-}
    {-# LANGUAGE TypeApplications #-}

    module Example where

    import Data.Text (Text)
    import GHC.Generics (Generic)
    import Dhall (ToDhall)
    import Dhall.Diff (Diff)
    import OldType (OldType)
    import NewType (NewType)

    import qualified Dhall
    import qualified Dhall.Core as Core
    import qualified Dhall.Diff as Diff

    diffType :: forall a b . (ToDhall a, ToDhall b) => Diff
    diffType = do
    Diff.diff
    (Core.denote (Dhall.declared (Dhall.inject @a)))
    (Core.denote (Dhall.declared (Dhall.inject @b)))

    main :: IO ()
    main = do
    print (Diff.doc (diffType @OldType @NewType))
    13 changes: 13 additions & 0 deletions NewType.hs
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    {-# LANGUAGE DeriveAnyClass #-}
    {-# LANGUAGE DeriveGeneric #-}

    module NewType where

    import Data.Text (Text)
    import Dhall (ToDhall)
    import GHC.Generics (Generic)

    data NewType
    = Foo{ bar :: Text, baz :: Bool, new :: [Double] }
    | Qux{ qyzzy :: Integer }
    deriving (Generic, ToDhall)
    14 changes: 14 additions & 0 deletions OldType.hs
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    {-# LANGUAGE DeriveAnyClass #-}
    {-# LANGUAGE DeriveGeneric #-}

    module OldType where

    import Data.Text (Text)
    import Dhall (ToDhall)
    import GHC.Generics (Generic)
    import Numeric.Natural (Natural)

    data OldType
    = Foo{ bar :: Text, baz :: Bool }
    | Qux{ qyzzy :: Natural }
    deriving (Generic, ToDhall)
    7 changes: 7 additions & 0 deletions output.txt
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    < Foo : : { + new : …
    , …
    }
    | Qux : : { qyzzy : - Natural
    + Integer
    }
    >