From c94a0946d9767454f4b619210dab72edb29649f6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cl=C3=A9ment=20Hurlin?= <clement.hurlin@tweag.io>
Date: Fri, 6 Oct 2023 10:51:35 +0200
Subject: [PATCH] Add BabbageEraOnly

---
 cardano-api/cardano-api.cabal                 |  1 +
 .../Cardano/Api/Eon/BabbageEraOnly.hs         | 55 +++++++++++++++++++
 2 files changed, 56 insertions(+)
 create mode 100644 cardano-api/internal/Cardano/Api/Eon/BabbageEraOnly.hs

diff --git a/cardano-api/cardano-api.cabal b/cardano-api/cardano-api.cabal
index 34bde8ef85..eecff4cabd 100644
--- a/cardano-api/cardano-api.cabal
+++ b/cardano-api/cardano-api.cabal
@@ -57,6 +57,7 @@ library internal
                         Cardano.Api.Eon.AllegraEraOnwards
                         Cardano.Api.Eon.AlonzoEraOnly
                         Cardano.Api.Eon.AlonzoEraOnwards
+                        Cardano.Api.Eon.BabbageEraOnly
                         Cardano.Api.Eon.BabbageEraOnwards
                         Cardano.Api.Eon.ByronAndAllegraEraOnwards
                         Cardano.Api.Eon.ByronEraOnly
diff --git a/cardano-api/internal/Cardano/Api/Eon/BabbageEraOnly.hs b/cardano-api/internal/Cardano/Api/Eon/BabbageEraOnly.hs
new file mode 100644
index 0000000000..e9acf19c6c
--- /dev/null
+++ b/cardano-api/internal/Cardano/Api/Eon/BabbageEraOnly.hs
@@ -0,0 +1,55 @@
+{-# LANGUAGE ConstraintKinds #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE RankNTypes #-}
+{-# LANGUAGE StandaloneDeriving #-}
+{-# LANGUAGE TypeFamilies #-}
+
+module Cardano.Api.Eon.BabbageEraOnly
+  ( BabbageEraOnly(..)
+  , babbageEraOnlyConstraints
+  , babbageEraOnlyToCardanoEra
+
+  , BabbageEraOnlyConstraints
+  ) where
+
+import           Cardano.Api.Eras.Core
+
+import           Data.Typeable (Typeable)
+
+data BabbageEraOnly era where
+  BabbageEraOnlyBabbage  :: BabbageEraOnly BabbageEra
+
+deriving instance Show (BabbageEraOnly era)
+deriving instance Eq (BabbageEraOnly era)
+
+instance Eon BabbageEraOnly where
+  inEonForEra no yes = \case
+    ByronEra    -> no
+    ShelleyEra  -> no
+    AllegraEra  -> no
+    MaryEra     -> no
+    AlonzoEra   -> no
+    BabbageEra  -> yes BabbageEraOnlyBabbage
+    ConwayEra   -> no
+
+instance ToCardanoEra BabbageEraOnly where
+  toCardanoEra = \case
+    BabbageEraOnlyBabbage  -> BabbageEra
+
+type BabbageEraOnlyConstraints era =
+  ( IsCardanoEra era
+  , Typeable era
+  )
+
+babbageEraOnlyConstraints :: ()
+  => BabbageEraOnly era
+  -> (BabbageEraOnlyConstraints era => a)
+  -> a
+babbageEraOnlyConstraints = \case
+  BabbageEraOnlyBabbage  -> id
+
+babbageEraOnlyToCardanoEra :: BabbageEraOnly era -> CardanoEra era
+babbageEraOnlyToCardanoEra = \case
+  BabbageEraOnlyBabbage  -> BabbageEra