now the datatype Tree is only internal. All API functions are working with Expr directly. Commands gt, gr, p and rf filter out the output via the typechecker

src/PGF/PMCFG.hs

@@ -23,7 +23,7 @@ type Profile = [Int]
 data Production
   = FApply  {-# UNPACK #-} !FunId [FCat]
   | FCoerce {-# UNPACK #-} !FCat
-  | FConst  Tree [String]
+  | FConst  Expr [String]
   deriving (Eq,Ord,Show)
 data FFun  = FFun CId [Profile] {-# UNPACK #-} !(UArray FIndex SeqId) deriving (Eq,Ord,Show)
 type FSeq  = Array FPointPos FSymbol