Some experiment

cardano-api/cardano-api.cabal

@@ -213,6 +213,7 @@ library internal
     scientific,
     serialise,
     small-steps ^>=1.1,
+    some,
     sop-core,
     stm,
     strict-sop-core,

cardano-api/internal/Cardano/Api/Eon/ShelleyBasedEra.hs

@@ -242,13 +242,13 @@ shelleyBasedEraConstraints = \case
   ShelleyBasedEraBabbage -> id
   ShelleyBasedEraConway -> id
 
-data AnyShelleyBasedEra where
-  AnyShelleyBasedEra
-    :: Typeable era
-    => ShelleyBasedEra era
-    -> AnyShelleyBasedEra
+-- deriving instance Show AnyShelleyBasedEra
 
-deriving instance Show AnyShelleyBasedEra
+-- instance Eq AnyShelleyBasedEra where
+--     AnyShelleyBasedEra sbe == AnyShelleyBasedEra sbe' =
+--       case testEquality sbe sbe' of
+--         Nothing   -> False
+--         Just Refl -> True -- since no constructors share types
 
 instance Eq AnyShelleyBasedEra where
   AnyShelleyBasedEra sbe == AnyShelleyBasedEra sbe' =

cardano-api/internal/Cardano/Api/Governance/Actions/VotingProcedure.hs

@@ -30,6 +30,7 @@ import Cardano.Ledger.Core (EraCrypto)
 import qualified Cardano.Ledger.Core as L
 import Control.Monad (foldM)
 import qualified Data.Map as Map
+import Data.Set (Set)
 import qualified Data.Set as Set
 import Data.Text (Text)
 import qualified Data.Text.Encoding as Text

cardano-api/internal/Cardano/Api/LedgerState.hs

@@ -275,7 +275,7 @@ data LedgerStateError
     -- prior to the termination epoch.
     TerminationEpochReached EpochNo
   | UnexpectedLedgerState
-      AnyShelleyBasedEra
+      (Some ShelleyBasedEra)
       -- ^ Expected era
       (Consensus.CardanoLedgerState Consensus.StandardCrypto)
       -- ^ Ledgerstate from an unexpected era
@@ -1206,7 +1206,7 @@ getNewEpochState
   -> Consensus.CardanoLedgerState Consensus.StandardCrypto
   -> Either LedgerStateError (ShelleyAPI.NewEpochState (ShelleyLedgerEra era))
 getNewEpochState era x = do
-  let err = UnexpectedLedgerState (shelleyBasedEraConstraints era $ AnyShelleyBasedEra era) x
+  let err = UnexpectedLedgerState (shelleyBasedEraConstraints era $ Some era) x
   case era of
     ShelleyBasedEraShelley ->
       case x of

cardano-api/internal/Cardano/Api/SerialiseLedgerCddl.hs

@@ -322,26 +322,26 @@ deserialiseFromTextEnvelopeCddlAnyOf types teCddl =
 -- Parse the text into types because this will increase code readability and
 -- will make it easier to keep track of the different Cddl descriptions via
 -- a single sum data type.
-cddlTypeToEra :: Text -> Either TextEnvelopeCddlError AnyShelleyBasedEra
+cddlTypeToEra :: Text -> Either TextEnvelopeCddlError (Some ShelleyBasedEra)
 cddlTypeToEra = \case
-  "Witnessed Tx ShelleyEra" -> return $ AnyShelleyBasedEra ShelleyBasedEraShelley
-  "Witnessed Tx AllegraEra" -> return $ AnyShelleyBasedEra ShelleyBasedEraAllegra
-  "Witnessed Tx MaryEra" -> return $ AnyShelleyBasedEra ShelleyBasedEraMary
-  "Witnessed Tx AlonzoEra" -> return $ AnyShelleyBasedEra ShelleyBasedEraAlonzo
-  "Witnessed Tx BabbageEra" -> return $ AnyShelleyBasedEra ShelleyBasedEraBabbage
-  "Witnessed Tx ConwayEra" -> return $ AnyShelleyBasedEra ShelleyBasedEraConway
-  "Unwitnessed Tx ShelleyEra" -> return $ AnyShelleyBasedEra ShelleyBasedEraShelley
-  "Unwitnessed Tx AllegraEra" -> return $ AnyShelleyBasedEra ShelleyBasedEraAllegra
-  "Unwitnessed Tx MaryEra" -> return $ AnyShelleyBasedEra ShelleyBasedEraMary
-  "Unwitnessed Tx AlonzoEra" -> return $ AnyShelleyBasedEra ShelleyBasedEraAlonzo
-  "Unwitnessed Tx BabbageEra" -> return $ AnyShelleyBasedEra ShelleyBasedEraBabbage
-  "Unwitnessed Tx ConwayEra" -> return $ AnyShelleyBasedEra ShelleyBasedEraConway
-  "TxWitness ShelleyEra" -> return $ AnyShelleyBasedEra ShelleyBasedEraShelley
-  "TxWitness AllegraEra" -> return $ AnyShelleyBasedEra ShelleyBasedEraAllegra
-  "TxWitness MaryEra" -> return $ AnyShelleyBasedEra ShelleyBasedEraMary
-  "TxWitness AlonzoEra" -> return $ AnyShelleyBasedEra ShelleyBasedEraAlonzo
-  "TxWitness BabbageEra" -> return $ AnyShelleyBasedEra ShelleyBasedEraBabbage
-  "TxWitness ConwayEra" -> return $ AnyShelleyBasedEra ShelleyBasedEraConway
+  "Witnessed Tx ShelleyEra" -> return $ Some ShelleyBasedEraShelley
+  "Witnessed Tx AllegraEra" -> return $ Some ShelleyBasedEraAllegra
+  "Witnessed Tx MaryEra" -> return $ Some ShelleyBasedEraMary
+  "Witnessed Tx AlonzoEra" -> return $ Some ShelleyBasedEraAlonzo
+  "Witnessed Tx BabbageEra" -> return $ Some ShelleyBasedEraBabbage
+  "Witnessed Tx ConwayEra" -> return $ Some ShelleyBasedEraConway
+  "Unwitnessed Tx ShelleyEra" -> return $ Some ShelleyBasedEraShelley
+  "Unwitnessed Tx AllegraEra" -> return $ Some ShelleyBasedEraAllegra
+  "Unwitnessed Tx MaryEra" -> return $ Some ShelleyBasedEraMary
+  "Unwitnessed Tx AlonzoEra" -> return $ Some ShelleyBasedEraAlonzo
+  "Unwitnessed Tx BabbageEra" -> return $ Some ShelleyBasedEraBabbage
+  "Unwitnessed Tx ConwayEra" -> return $ Some ShelleyBasedEraConway
+  "TxWitness ShelleyEra" -> return $ Some ShelleyBasedEraShelley
+  "TxWitness AllegraEra" -> return $ Some ShelleyBasedEraAllegra
+  "TxWitness MaryEra" -> return $ Some ShelleyBasedEraMary
+  "TxWitness AlonzoEra" -> return $ Some ShelleyBasedEraAlonzo
+  "TxWitness BabbageEra" -> return $ Some ShelleyBasedEraBabbage
+  "TxWitness ConwayEra" -> return $ Some ShelleyBasedEraConway
   unknownCddlType -> Left $ TextEnvelopeCddlErrUnknownType unknownCddlType
 
 readFileTextEnvelopeCddlAnyOf

cardano-api/test/cardano-api-test/Test/Cardano/Api/Eras.hs

@@ -20,7 +20,7 @@ import Test.Tasty.Hedgehog (testProperty)
 prop_maxBound_CardanoMatchesShelley :: Property
 prop_maxBound_CardanoMatchesShelley = property $ do
   AnyCardanoEra era <- forAll $ Gen.element [maxBound]
-  AnyShelleyBasedEra sbe <- forAll $ Gen.element [maxBound]
+  Some sbe <- forAll $ Gen.element [maxBound]
 
   fromEnum (anyCardanoEra era) === fromEnum (anyCardanoEra (toCardanoEra sbe))
 
@@ -43,7 +43,7 @@ prop_toJSON_CardanoMatchesShelley :: Property
 prop_toJSON_CardanoMatchesShelley = property $ do
   AnyShelleyBasedEra sbe <- forAll $ Gen.element [minBound .. maxBound]
 
-  toJSON (AnyShelleyBasedEra sbe) === toJSON (anyCardanoEra (toCardanoEra sbe))
+  toJSON (Some sbe) === toJSON (anyCardanoEra (toCardanoEra sbe))
 
 tests :: TestTree
 tests =