further refactoring in Russian

next-lib/src/slavic/CommonSlavic.gf

@@ -3,4 +3,20 @@ resource CommonSlavic = ParamX ** open Prelude in {
 param
   Gender = Masc | Fem | Neut ;
   Animacy = Animate | Inanimate ;
+
+  GenNum = GSg Gender | GPl ;
+
+oper
+  gennum : Gender -> Number -> GenNum = \g,n ->
+    case n of {
+      Sg => GSg g ;
+      Pl => GPl
+      } ;
+
+  numGenNum : GenNum -> Number = \gn -> 
+    case gn of {
+      GSg _  => Sg ;
+      GPl    => Pl
+    } ;
+
 }