Messages and commands are nearly identical: they both have a name,

they can both have parameters stashed in a table, and they both play
stuff out of the actor command list.  Merge them; now the only
difference between playing and broadcasting a command is that playing
plays recursively on a tree and broadcasting sends to all subscribers.

The distinction between "messages" and "commands" is cosmetic now;
everything is a message.  The only thing special about commands intended
to be received as a broadcast is the "Message" suffix, which subscribes it.

stepmania/src/NoteDisplay.cpp

@@ -746,12 +746,9 @@ void NoteDisplay::DrawTap( const TapNote& tn, int iCol, float fBeat, bool bOnSam
 
 	if( tn.type == TapNote::attack )
 	{
-		Lua *L = LUA->Get();
-		LuaTable tab;
-		LuaHelpers::Push( L, tn.sAttackModifiers );
-		tab.Set( L, "Modifiers" );
-		pActor->PlayCommand( "SetAttack", &tab );
-		LUA->Release( L );
+		Message msg( "SetAttack" );
+		msg.SetParam( "Modifiers", tn.sAttackModifiers );
+		pActor->HandleMessage( msg );
 	}
 
 	const float fYOffset = ArrowEffects::GetYOffset( m_pPlayerState, iCol, fBeat );