Hello, I wanted to try using OOHaskell as a library, but I've run into some problems I don't understand. I downloaded the copy from: http://homepages.cwi.nl/~ralf/OOHaskell/ In the HList subdirectory I created a .cabal file which exposes as many of the modules in HList as I could. I then installed the HList library using cabal. Back in the main OOHaskell directory I created a .cabal file for OOHaskell which depended on the newly installed HList library. The OOHaskell library exposes the modules: DeepNarrow New Nominal OOHaskell After I installed the OOHaskell library I ran: ghc --make -package OOHaskell -package HList SimpleIO.hs Chasing modules from: SimpleIO.hs Compiling Nominal ( ./Nominal.hs, ./Nominal.o ) Compiling New ( ./New.hs, ./New.o ) Compiling DeepNarrow ( ./DeepNarrow.hs, ./DeepNarrow.o ) Compiling OOHaskell ( ./OOHaskell.hs, ./OOHaskell.o ) Compiling SimpleIO ( SimpleIO.hs, SimpleIO.o ) SimpleIO.hs:44:11: No instance for (HasField (Proxy Field1) HNil v) arising from use of `foo' at SimpleIO.hs:44:11-13 Probable fix: add an instance declaration for (HasField (Proxy Field1) HNil v) In the definition of `testfoo': testfoo = foo ((field1 .=. True) .*. emptyRecord) SimpleIO.hs:116:7: No instance for (HasField (Proxy MoveX) HNil (a -> IO t)) arising from use of `#' at SimpleIO.hs:116:7 Probable fix: add an instance declaration for (HasField (Proxy MoveX) HNil (a -> IO t)) In the first argument of `($)', namely `p # moveX' In a 'do' expression: (p # moveX) $ 3 In the definition of `myFirstOOP': myFirstOOP = do p <- point (p # getX) >>= System.IO.print (p # moveX) $ 3 (p # getX) >>= System.IO.print SimpleIO.hs:124:19: No instance for (HasField (Proxy MutableX) HNil (IORef a)) arising from use of `#' at SimpleIO.hs:124:19 Probable fix: add an instance declaration for (HasField (Proxy MutableX) HNil (IORef a)) In the first argument of `writeIORef', namely `(p # mutableX)' In a 'do' expression: writeIORef (p # mutableX) 42 In the definition of `mySecondOOP': mySecondOOP = do p <- point writeIORef (p # mutableX) 42 (p # getX) >>= System.IO.print SimpleIO.hs:177:23: No instance for (HasField (Proxy GetX) HNil (IO a)) arising from use of `#' at SimpleIO.hs:177:23 Probable fix: add an instance declaration for (HasField (Proxy GetX) HNil (IO a)) In the second argument of `(>>=)', namely `(# getX)' In the first argument of `(>>=)', namely `localClass >>= ((# getX))' In the result of a 'do' expression: (localClass >>= ((# getX))) >>= System.IO.print SimpleIO.hs:225:8: No instance for (HasField (Proxy GetOffset) HNil (IO a)) arising from use of `#' at SimpleIO.hs:225:8 Probable fix: add an instance declaration for (HasField (Proxy GetOffset) HNil (IO a)) In the first argument of `(>>=)', namely `p # getOffset' In the result of a 'do' expression: (p # getOffset) >>= System.IO.print In the definition of `testPara': testPara = do p <- para_point 1 (p # getX) >>= System.IO.print (p # moveX) $ 2 (p # getX) >>= System.IO.print (p # getOffset) >>= System.IO.print To investigate this further, in the OOHaskell directory I typed: $ ghci -fglasgow-exts -fallow-overlapping-instances -fallow-undecidable-instances -i./HList ShapesLub.hs ___ ___ _ / _ \ /\ /\/ __(_) / /_\// /_/ / / | | GHC Interactive, version 6.4.2, for Haskell 98. / /_\\/ __ / /___| | http://www.haskell.org/ghc/ \____/\/ /_/\____/|_| Type :? for help. Loading package base-1.0 ... linking ... done. Compiling FakePrelude ( ./HList/FakePrelude.hs, interpreted ) Compiling HListPrelude ( ./HList/HListPrelude.hs, interpreted ) Compiling GhcExperiments ( ./HList/GhcExperiments.hs, interpreted ) Compiling HArray ( ./HList/HArray.hs, interpreted ) Compiling HZip ( ./HList/HZip.hs, interpreted ) Compiling HOccurs ( ./HList/HOccurs.hs, interpreted ) Compiling HTypeIndexed ( ./HList/HTypeIndexed.hs, interpreted ) Compiling Record ( ./HList/Record.hs, interpreted ) Compiling GhcRecord ( ./HList/GhcRecord.hs, interpreted ) Compiling Label4 ( ./HList/Label4.hs, interpreted ) Compiling New ( ./New.hs, interpreted ) Compiling TIP ( ./HList/TIP.hs, interpreted ) Compiling TIC ( ./HList/TIC.hs, interpreted ) Compiling GhcSyntax ( ./HList/GhcSyntax.hs, interpreted ) Compiling TypeCastGeneric1 ( ./HList/TypeCastGeneric1.hs, interpreted ) Compiling TypeEqBoolGeneric ( ./HList/TypeEqBoolGeneric.hs, interpreted ) Compiling TypeEqGeneric1 ( ./HList/TypeEqGeneric1.hs, interpreted ) Compiling Variant ( ./HList/Variant.hs, interpreted ) Compiling Nominal ( ./Nominal.hs, interpreted ) Compiling CommonMain ( ./HList/CommonMain.hs, interpreted ) Compiling DeepNarrow ( ./DeepNarrow.hs, interpreted ) Compiling OOHaskell ( ./OOHaskell.hs, interpreted ) Compiling Shapes ( ./Shapes.hs, interpreted ) Compiling ShapesLub ( ShapesLub.hs, interpreted ) Ok, modules loaded: ShapesLub, Shapes, OOHaskell, DeepNarrow, CommonMain, Nominal, Variant, TypeEqGeneric1, TypeEqBoolGeneric, TypeCastGeneric1, GhcSyntax, TIC, TIP, New, Label4, GhcRecord, Record, HTypeIndexed, HOccurs, HZip, HArray, GhcExperiments, HListPrelude, FakePrelude. *ShapesLub> main Drawing a Rectangle at:(10,20), width 5, height 6 Drawing a Rectangle at:(110,120), width 5, height 6 Drawing a Circle at:(15,25), radius 8 Drawing a Circle at:(115,125), radius 8 Drawing a Rectangle at:(0,0), width 30, height 15 *ShapesLub> So that seemed to work, but: $ ghci -fglasgow-exts -fallow-overlapping-instances -fallow-undecidable-instances -package OOHaskell -package HList ShapesLub.hs ___ ___ _ / _ \ /\ /\/ __(_) / /_\// /_/ / / | | GHC Interactive, version 6.4.2, for Haskell 98. / /_\\/ __ / /___| | http://www.haskell.org/ghc/ \____/\/ /_/\____/|_| Type :? for help. Loading package base-1.0 ... linking ... done. Loading package HList-0.1 ... linking ... done. Loading package OOHaskell-0.1 ... linking ... done. Skipping Nominal ( ./Nominal.hs, ./Nominal.o ) Skipping New ( ./New.hs, ./New.o ) Skipping DeepNarrow ( ./DeepNarrow.hs, ./DeepNarrow.o ) Skipping OOHaskell ( ./OOHaskell.hs, ./OOHaskell.o ) Compiling Shapes ( ./Shapes.hs, interpreted ) Compiling ShapesLub ( ShapesLub.hs, interpreted ) ShapesLub.hs:30:19: No instances for (HasField (Proxy MoveTo) HNil (a5 -> a6 -> IO t5), HasField (Proxy GetY) HNil (IO a6), HasField (Proxy GetX) HNil (IO a5), HasField (Proxy SetY) HNil (t4 -> t t1), HasField (Proxy SetX) HNil (t2 -> t t3), HasField (Proxy GetWidth) HNil (IO a7), HasField (Proxy GetHeight) HNil (IO a8), HExtract HNil (Proxy Draw) (IO ())) arising from use of `rectangle' at ShapesLub.hs:30:19-27 Probable fix: add an instance declaration for (HasField (Proxy MoveTo) HNil (a5 -> a6 -> IO t5), HasField (Proxy GetY) HNil (IO a6), HasField (Proxy GetX) HNil (IO a5), HasField (Proxy SetY) HNil (t4 -> t t1), HasField (Proxy SetX) HNil (t2 -> t t3), HasField (Proxy GetWidth) HNil (IO a7), HasField (Proxy GetHeight) HNil (IO a8), HExtract HNil (Proxy Draw) (IO ())) In the first argument of `mfix', namely `(rectangle (10 :: Int) (20 :: Int) 5 6)' In a 'do' expression: s1 <- mfix (rectangle (10 :: Int) (20 :: Int) 5 6) In the definition of `main': main = do s1 <- mfix (rectangle (10 :: Int) (20 :: Int) 5 6) s2 <- mfix (circle (15 :: Int) 25 8) let scribble = ... mapM_ (\ shape -> ...) scribble arec <- mfix (rectangle (0 :: Int) (0 :: Int) 15 15) (arec # setWidth) $ 30 arec # draw ShapesLub.hs:31:19: No instance for (HasField (Proxy GetRadius) HNil (IO a6)) arising from use of `circle' at ShapesLub.hs:31:19-24 Probable fix: add an instance declaration for (HasField (Proxy GetRadius) HNil (IO a6)) In the first argument of `mfix', namely `(circle (15 :: Int) 25 8)' In a 'do' expression: s2 <- mfix (circle (15 :: Int) 25 8) In the definition of `main': main = do s1 <- mfix (rectangle (10 :: Int) (20 :: Int) 5 6) s2 <- mfix (circle (15 :: Int) 25 8) let scribble = ... mapM_ (\ shape -> ...) scribble arec <- mfix (rectangle (0 :: Int) (0 :: Int) 15 15) (arec # setWidth) $ 30 arec # draw ShapesLub.hs:38:34: No instance for (HasField (Proxy RMoveTo) HNil (t -> t1 -> IO t2)) arising from use of `#' at ShapesLub.hs:38:34 Probable fix: add an instance declaration for (HasField (Proxy RMoveTo) HNil (t -> t1 -> IO t2)) In a 'do' expression: (shape # rMoveTo) 100 100 In a lambda abstraction: \ shape -> do shape # draw (shape # rMoveTo) 100 100 shape # draw In the first argument of `mapM_', namely `(\ shape -> do shape # draw (shape # rMoveTo) 100 100 shape # draw)' ShapesLub.hs:44:12: No instance for (HasField (Proxy SetWidth) HNil (a -> IO t)) arising from use of `#' at ShapesLub.hs:44:12 Probable fix: add an instance declaration for (HasField (Proxy SetWidth) HNil (a -> IO t)) In the first argument of `($)', namely `arec # setWidth' In a 'do' expression: (arec # setWidth) $ 30 In the definition of `main': main = do s1 <- mfix (rectangle (10 :: Int) (20 :: Int) 5 6) s2 <- mfix (circle (15 :: Int) 25 8) let scribble = ... mapM_ (\ shape -> ...) scribble arec <- mfix (rectangle (0 :: Int) (0 :: Int) 15 15) (arec # setWidth) $ 30 arec # draw ShapesLub.hs:46:12: No instance for (HasField (Proxy Draw) HNil (IO b)) arising from use of `#' at ShapesLub.hs:46:12 Probable fix: add an instance declaration for (HasField (Proxy Draw) HNil (IO b)) In the result of a 'do' expression: arec # draw In the definition of `main': main = do s1 <- mfix (rectangle (10 :: Int) (20 :: Int) 5 6) s2 <- mfix (circle (15 :: Int) 25 8) let scribble = ... mapM_ (\ shape -> ...) scribble arec <- mfix (rectangle (0 :: Int) (0 :: Int) 15 15) (arec # setWidth) $ 30 arec # draw Failed, modules loaded: Shapes, OOHaskell, DeepNarrow, New, Nominal. *Shapes> Inspecting HasField and Proxy in the working ghci says: *ShapesLub> :i HasField class HasField l r v | l r -> v where hLookupByLabel :: l -> r -> v -- Defined at ./HList/Record.hs:140:6 instance (HasField l x v, Nomination f) => HasField l (N f x) v -- Defined at ./Nominal.hs:49:0 instance HasField l r v => HasField l (Record r) v -- Defined at ./HList/Record.hs:143:0 instance (HEq l l' b, HasField' b l (HCons (l', v') r) v) => HasField l (HCons (l', v') r) v -- Defined at ./HList/Record.hs:149:0 *ShapesLub> :i Proxy data Proxy e -- Defined at ./HList/FakePrelude.hs:218:5 instance Show (Proxy e) -- Defined at ./HList/FakePrelude.hs:219:0 instance Typeable x => Typeable (Proxy x) -- Defined at ./HList/GhcRecord.hs:229:0 instance TypeEq x y b => HEq (Proxy x) (Proxy y) b -- Defined at ./HList/Label4.hs:27:0 instance (HType2HNat e l n, HTypes2HNats ps l ns) => HTypes2HNats (HCons (Proxy e) ps) l (HCons n ns) -- Defined at ./HList/HTypeIndexed.hs:90:0 instance Typeable x => ShowLabel (Proxy x) -- Defined at ./HList/Label4.hs:32:0 instance Fail (ProxyFound x) => HasNoProxies (HCons (Proxy x) l) -- Defined at ./HList/GhcRecord.hs:73:0 instance HTypeProxied l => HTypeProxied (HCons (Proxy e) l) -- Defined at ./HList/TIC.hs:68:0 instance HMaybied l l' => HMaybied (HCons (Proxy e) l) (HCons (Maybe e) l') -- Defined at ./HList/Variant.hs:53:0 While, the ouput in the non-working ghci sessions has equivalent output: *Shapes> :i HasField class HasField l r v | l r -> v where hLookupByLabel :: l -> r -> v -- Imported from Record instance (HasField l x v, Nomination f) => HasField l (N f x) v -- Imported from Nominal instance (HEq l l' b, HasField' b l (HCons (l', v') r) v) => HasField l (HCons (l', v') r) v -- Imported from Record instance HasField l r v => HasField l (Record r) v -- Imported from Record *Shapes> :i Proxy data Proxy e -- Imported from FakePrelude instance Show (Proxy e) -- Imported from FakePrelude instance Typeable x => Typeable (Proxy x) -- Imported from GhcRecord instance TypeEq x y b => HEq (Proxy x) (Proxy y) b -- Imported from Label4 instance Typeable x => ShowLabel (Proxy x) -- Imported from Label4 instance Fail (ProxyFound x) => HasNoProxies (HCons (Proxy x) l) -- Imported from GhcRecord instance HMaybied l l' => HMaybied (HCons (Proxy e) l) (HCons (Maybe e) l') -- Imported from Variant instance HTypeProxied l => HTypeProxied (HCons (Proxy e) l) -- Imported from TIC instance (HType2HNat e l n, HTypes2HNats ps l ns) => HTypes2HNats (HCons (Proxy e) ps) l (HCons n ns) -- Imported from HTypeIndexed I'm at a loss to figure out why the OOHaskell library I created does not behave the same as building the examples next to the HList source. Thanks, Jason