[Haskell-cafe] OOHaskell problems

1 Oct 2006

      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

[Haskell-cafe] OOHaskell problems

Jason Dagit