Example

cardano-cli/src/Cardano/CLI/Options.hs

@@ -68,6 +68,17 @@ parseByron mNetworkId =
     , command' "byron" "Byron specific commands" $ parseByronCommands mNetworkId
     ]
 
+{-
+We don't care about the era here because this is simply a backwards compatible
+command that is expected to work over all eras.
+
+We need to be able to parse: Inputs, outputs, update proposals, stake registration, stake delegation and
+pool registration is all that we need in previous eras.
+-}
+parseShelleyToBeforeMainnet :: EnvCli -> Parser ClientCommand
+parseShelleyToBeforeMainnet _ = PreMainnetCommand <$> error "TODO"
+
+
 parsePing :: Parser ClientCommand
 parsePing = CliPingCommand <$> parsePingCmd
 

cardano-cli/src/Cardano/CLI/Run.hs

@@ -9,6 +9,8 @@ module Cardano.CLI.Run
   , runClientCommand
   ) where
 
+import           Cardano.Api
+
 import           Cardano.CLI.Byron.Commands (ByronCommand)
 import           Cardano.CLI.Byron.Run (ByronClientCmdError, renderByronClientCmdError,
                    runByronClientCommand)
@@ -45,6 +47,7 @@ data ClientCommand =
 
     -- | Byron Related Commands
   | ByronCommand ByronCommand
+  | PreMainnetCommand PreMainnetCommand
 
     -- | Legacy shelley-based Commands
   | LegacyCmds LegacyCmds
@@ -54,6 +57,19 @@ data ClientCommand =
   | forall a. Help ParserPrefs (ParserInfo a)
   | DisplayVersion
 
+
+data PreMainnetCommand
+ = PreMainnetTxBuild PreMainnetTransactionBuildCmdArgs
+
+
+-- E.g something like this that offers the minimum required functionality.
+-- We also need key generation commands to work to run SPOs etc
+data PreMainnetTransactionBuildCmdArgs = TransactionBuildCmdArgs
+  { nodeSocketPath          :: !SocketPath
+  , networkId               :: !NetworkId
+  , txins                    :: ![TxIn]
+  }
+
 data ClientCommandErrors
   = ByronClientError ByronClientCmdError
   | CmdError Text CmdError