diff --git a/CSPM-Interpreter.cabal b/CSPM-Interpreter.cabal
--- a/CSPM-Interpreter.cabal
+++ b/CSPM-Interpreter.cabal
@@ -1,5 +1,5 @@
 Name:                CSPM-Interpreter
-Version:             0.5.1.0
+Version:             0.6.0.3
 
 Synopsis:            An interpreter for CSPM
 Description:
@@ -13,26 +13,28 @@
 License:             BSD3
 category:            Language,Formal Methods,Concurrency
 License-File:        LICENSE
-Author:              2010 - 2011 Marc Fontaine
+Author:              2010 - 2012 Marc Fontaine
 Maintainer:          Marc Fontaine <fontaine@cs.uni-duesseldorf.de>
 Stability:           experimental
-Tested-With:         GHC == 7.0.3
+Tested-With:         GHC == 7.4.1
 
 cabal-Version:       >= 1.10
 build-type: Simple
 Extra-source-files:
 Library
   Build-Depends:
-    CSPM-Frontend >= 0.7 && < 0.8
+    CSPM-Frontend >= 0.9 && < 0.10
     ,CSPM-CoreLanguage >= 0.3 && < 0.4
+    ,prettyclass >= 1.0 && < 1.1
     ,base >= 4.0 && < 5.0
     ,containers >= 0.4 && < 0.5
-    ,mtl (>= 2.0 && < 2.1 ) || (>= 1.1 && < 1.2)
-    ,array >= 0.3 && <0.4
+    ,mtl
+    ,array >= 0.4 && <0.5
     ,syb >= 0.3 && < 0.4
 
+
   Default-Language: Haskell2010
-  GHC-Options: -funbox-strict-fields -O2 -Wall
+  GHC-Options: -funbox-strict-fields -O2 -Wall  -fsimpl-tick-factor=400
   Other-Extensions: DeriveDataTypeable, GeneralizedNewtypeDeriving
   Hs-Source-Dirs:       src
   Exposed-modules:
@@ -43,6 +45,7 @@
     CSPM.Interpreter.Hash
     CSPM.Interpreter.ClosureSet
     CSPM.Interpreter.Test.CLI
+    CSPM.Interpreter.Pretty
   Other-modules:
     CSPM.Interpreter.Renaming
     CSPM.Interpreter.PrepareAST
diff --git a/src/CSPM/Interpreter.hs b/src/CSPM/Interpreter.hs
--- a/src/CSPM/Interpreter.hs
+++ b/src/CSPM/Interpreter.hs
@@ -33,6 +33,7 @@
 import CSPM.Interpreter.Eval
 import CSPM.Interpreter.PrepareAST
 import CSPM.Interpreter.Test.CLI
+import CSPM.Interpreter.Pretty ()
 
 import Language.CSPM.AST as AST
 
diff --git a/src/CSPM/Interpreter/ClosureSet.hs b/src/CSPM/Interpreter/ClosureSet.hs
--- a/src/CSPM/Interpreter/ClosureSet.hs
+++ b/src/CSPM/Interpreter/ClosureSet.hs
@@ -114,8 +114,8 @@
       PTAny {} -> throwFeatureNotImplemented "cannot enumerate PTAny (Set,Seq,INT)"
                     Nothing Nothing
       PTMap m -> foldl' (add path) acc $ Map.assocs m
-      PTRec s t -> foldl' (add path) acc $ zip (Set.elems s) $ repeat t
-      PTSingle v t -> worker acc (v:path) t
+      PTRec s r -> foldl' (add path) acc $ zip (Set.elems s) $ repeat r
+      PTSingle v r -> worker acc (v:path) r
       PTClosure l -> worker acc path l
     add :: [Value] -> [Value] -> (Value,PrefixTrie) -> [Value]
     add path acc (val,t) = worker acc (val:path) t
@@ -132,8 +132,8 @@
 valueToPT v = case v of
   VChannel c -> fieldsToPT [v] $ (SSet.Total : chanFields c)
   VDotTuple [] -> throwScriptError "valueToPT : empty dot-tuple" Nothing Nothing
-  VDotTuple l@(VChannel c : t) -> fieldsToPT l (SSet.Total : chanFields c)
-  VDotTuple l -> throwScriptError "valueToPT : dot-tuple does not start with a channel"
+  VDotTuple l@(VChannel c : _) -> fieldsToPT l (SSet.Total : chanFields c)
+  VDotTuple _ -> throwScriptError "valueToPT : dot-tuple does not start with a channel"
         Nothing $ Just v
   _ -> throwScriptError "valueToPT: cannot make a event-closure of value" 
         Nothing $ Just v
diff --git a/src/CSPM/Interpreter/Eval.hs b/src/CSPM/Interpreter/Eval.hs
--- a/src/CSPM/Interpreter/Eval.hs
+++ b/src/CSPM/Interpreter/Eval.hs
@@ -61,8 +61,6 @@
 runEnv :: Env -> EM x -> x
 runEnv env action = Reader.runReader (unEM action) env
 
-{- todo : check whether the order of the cases influences efficency. -}
-
 -- | Evaluate an expression in the 'EM' monad.
 eval :: LExp -> EM Value
 eval expr = case unLabel expr of
@@ -113,10 +111,10 @@
   CFalse -> return $ VBool False
   BoolSet -> return $ VSet $ Set.fromList [VBool True,VBool False]
 {-
-  many prob test contain unboundet INT
+  Many prob test contain unboundet INT
   IntSet -> return $ VAllInts
 -}
-  IntSet -> return $ VSet $ Set.fromList $ map VInt [0..100] --ToDo: fix this !!
+  IntSet -> return $ VSet $ Set.fromList $ map VInt [0..100] --ToDo: Fix this !!
   TupleExp l -> mapM eval l >>= return . VTuple
   Parens e -> eval e
   AndExp a b -> do
@@ -408,7 +406,7 @@
       y <- switchedOffProc b
       return $ VProcess $ o x y
 
--- | A process a module and return the top-level envirionment
+-- | Process a module and return the top-level envirionment.
 evalModule :: Module INT -> Env
 evalModule m
   = processDeclList (hs "TopLevelEnvirionment") emptyEnvirionment
@@ -518,8 +516,8 @@
     VInt {} -> return $ SSet.singleton v
     VChannel {} -> return $ SSet.singleton v
     VSet s -> return $ SSet.Proper s
--- todo : fixthis when we have ClosureExpressions
--- todo: this does not work for constructors that have fields
+-- todo: Fix this when we have ClosureExpressions.
+-- todo: This does not work for constructors that have fields.
     VDataType constrList -> return $ SSet.fromList $ map VConstructor constrList
     VNameType _ -> throwInternalError "nametype not implemented" (Just $ srcLoc expr) $ Just v
     VAllInts -> return $ SSet.fromList $ map VInt [0..10] --todo
@@ -544,11 +542,11 @@
     VChannel {} -> return v
     VConstructor {} -> return v
     VTuple {} -> return v 
-    VDotTuple {} -> return v -- todo : fix for genric buffers
+    VDotTuple {} -> return v -- todo : Fix for genric buffers
     VBool {} -> return v
 {-
-todo: support lists and sets as channel fields
-write test for VSet and VList
+todo: Dupport lists and sets as channel fields.
+Write test for VSet and VList.
 -}
     VSet {} -> return v
     VList {} -> return v        
@@ -556,7 +554,7 @@
     _ -> throwTypingError "Eval.hs : evalOutField" (Just $ srcLoc expr) $ Just v
 
 
-{- redo this: most procComprehensions work on sets ! -}
+{- redo this: Most procComprehensions work on sets ! -}
 evalProcCompL :: LExp -> LCompGenList -> EM [Process]
 evalProcCompL p comp = evalListComp ret $ unLabel comp
   where
@@ -565,7 +563,7 @@
       return [r]
 
 {-
-fdr does not remove duplicates from replicatesProc compostions 
+fdr does not remove duplicates from replicatesProc compostions,
 see examples/CSP/FDRFeatureTests/ReplicatedInterleaveSetDef.csp
 -}
 evalProcCompS :: LExp -> LCompGenList -> EM [Process]
@@ -575,8 +573,9 @@
   =     (evalSetComp ret $ unLabel comp)
     >>= (mapM processFromValue) . Set.toList
   where
-{- we intermediatley wrap processes with VProcess 
-if we make evalSetComp polymorphic we get the following error
+{-
+We intermediateley wrap processes with VProcess.
+If we make evalSetComp polymorphic we get the following error
 src/Language/CSPM/Interpreter/Eval.hs:536:0:
     Contexts differ in length
       (Use -XRelaxedPolyRec to allow this)
@@ -684,10 +683,10 @@
          env (zip patList valList)
 
 {-
-  going from
+  Going from
   callFkt fkt args = return $ tryFunCases (getFunCases fkt) args (getFunEnv fkt)
   to the version which supports partial application
-  costs ca 17 % in the fibonacci -example
+  costs approx. 17 % in the fibonacci -example.
 -}
     callFkt :: FunClosure -> [Value] -> EM Value
     callFkt fkt args
diff --git a/src/CSPM/Interpreter/Hash.hs b/src/CSPM/Interpreter/Hash.hs
--- a/src/CSPM/Interpreter/Hash.hs
+++ b/src/CSPM/Interpreter/Hash.hs
@@ -11,7 +11,7 @@
 -- Instances of the Hash class for interpreter types and core language types
 --
 ----------------------------------------------------------------------------
-{-# LANGUAGE TypeSynonymInstances,FlexibleInstances #-}
+{-# LANGUAGE TypeSynonymInstances,FlexibleInstances, BangPatterns #-}
 {-# OPTIONS_GHC -fno-warn-orphans #-}
 
 module CSPM.Interpreter.Hash
diff --git a/src/CSPM/Interpreter/PatternCompiler.hs b/src/CSPM/Interpreter/PatternCompiler.hs
--- a/src/CSPM/Interpreter/PatternCompiler.hs
+++ b/src/CSPM/Interpreter/PatternCompiler.hs
@@ -141,6 +141,7 @@
         l <- mapM lengthOfListPattern patl
         return $ sum l
       VarPat _ -> Nothing
+      WildCard -> Nothing
       Also patl -> do
         let l = map lengthOfListPattern patl
         -- todo: check that all length are equal:
diff --git a/src/CSPM/Interpreter/Pretty.hs b/src/CSPM/Interpreter/Pretty.hs
new file mode 100644
--- /dev/null
+++ b/src/CSPM/Interpreter/Pretty.hs
@@ -0,0 +1,48 @@
+----------------------------------------------------------------------------
+-- |
+-- Module      :  CSPM.Interpreter.Pretty
+-- Copyright   :  (c) Fontaine 2011
+-- License     :  BSD3
+--
+-- Maintainer  :  Fontaine@cs.uni-duesseldorf.de
+-- Stability   :  experimental
+-- Portability :  GHC-only
+--
+-- A pretty-printer for values.
+--
+----------------------------------------------------------------------------
+module CSPM.Interpreter.Pretty
+where
+
+import CSPM.Interpreter.Types
+import CSPM.Interpreter.ClosureSet (closureToSet)
+
+import Text.PrettyPrint.HughesPJClass
+import qualified Data.Set as Set
+
+instance Pretty Value where
+  pPrint v = case v of
+    VInt  i -> pPrint i
+    VBool True -> text "true"
+    VBool False -> text "false"
+    VList l -> text "<" <> commaList l <> text ">"
+    VTuple l -> parens $ commaList l
+    VDotTuple l -> parens $ hcat $ punctuate (text ".") $ map pPrint l
+    VSet s -> text "{" <> (commaList $ Set.toList s) <> text "}"
+    VClosure s -> text "{|" <> (commaList $ Set.toList $ closureToSet s) <> text "|}"
+    VProcess _ -> unPrintable "a process"
+    VChannel c -> text $ chanName c
+    VFun _ -> unPrintable "a function closure"
+    VUnit -> text "()"
+    VAllInts -> unPrintable "set of all Integer"
+    VAllSequences _  -> unPrintable "VAllSequences"
+    VConstructor c -> text $ constrName c
+    VDataType _ -> text "datatype"
+    VNameType _ -> text "nametype"
+    VPartialApplied {} -> unPrintable "partially applyed function"
+    _ -> unPrintable $ show v
+    where
+      commaList :: [Value] -> Doc
+      commaList = hcat . punctuate comma . map pPrint
+      unPrintable :: String -> Doc
+      unPrintable s = parens $ text "{-" <> text s <> text "-}"
diff --git a/src/CSPM/Interpreter/Test/CLI.hs b/src/CSPM/Interpreter/Test/CLI.hs
--- a/src/CSPM/Interpreter/Test/CLI.hs
+++ b/src/CSPM/Interpreter/Test/CLI.hs
@@ -42,7 +42,9 @@
 import CSPM.Interpreter.Types (Value)
 import CSPM.Interpreter.PrepareAST (prepareAST)
 import CSPM.Interpreter.CoreInstances ()
+import CSPM.Interpreter.Pretty ()
 
+import Text.PrettyPrint.HughesPJClass
 import System.Exit
 import System.CPUTime
 import Control.Exception.Base (evaluate)
@@ -63,7 +65,7 @@
         $ handleRenameError renameErrorHandler $
   do
     res <- evalFile False (Just fileName) expr
-    putStrLn $ show $ fst res
+    putStrLn $ prettyShow $ fst res
     exitSuccess
 
 {- Todo: clean up the mess below -}
@@ -120,7 +122,7 @@
     val :: Value
     val = (IntMap.!) (Types.getLetBindings env) $ AST.uniqueIdentId entry
   when verbose $ do
-     putStrLn $ "eval result         : " ++ show val
+     putStrLn $ "eval result         : " ++ prettyShow val
      time_finish_execute <- getCPUTime
      putStrLn $ "eval execution time : " ++ showTime (time_finish_execute - time_start_execute)
   return (val,env)
diff --git a/src/CSPM/Interpreter/Types.hs b/src/CSPM/Interpreter/Types.hs
--- a/src/CSPM/Interpreter/Types.hs
+++ b/src/CSPM/Interpreter/Types.hs
@@ -18,7 +18,7 @@
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
 {-# LANGUAGE StandaloneDeriving #-}
 {-# LANGUAGE DeriveDataTypeable #-}
-
+{-# LANGUAGE FlexibleInstances #-}
 module CSPM.Interpreter.Types
 where