Re: brain explosion in polymorphic state monad
I'm not sure why it's doing that, but you can see (and fix!) the same problem in a simpler case: data Foo a = forall b . Foo a b foo (Foo a _) f = let Foo _ b = f a in Foo a b This causes the same error. Presumably this has to do with the compiler worrying about escaping variables or something. I'm not sure. There's a workaround, though, which I bet will work in your case. First we define: refoo (Foo a _) (Foo _ b) = Foo a b Then we redefine the foo function using this: foo x@(Foo a _) f = refoo x (f a) and we have a semantically identical, but now acceptable, function. HTH - Hal -- Hal Daume III "Computer science is no more about computers| [EMAIL PROTECTED] than astronomy is about telescopes." -Dijkstra | www.isi.edu/~hdaume On Thu, 10 Oct 2002, mathieu wrote: > Hello, > > I am trying to define a polymorphic state monad using glasgow extensions and I got a >brain explosion of ghc when i try to compile it. > > Here is the code : > > newtype StateT s m a = MkStateT (s -> m (a, s)) > > instance Monad m => Monad (StateT s m) where > return x = MkStateT (\s -> return (x, s)) > MkStateT m1 >>= k = > MkStateT > (\s0 -> do (a, s1) <- m1 s0 >let MkStateT m2 = k a >m2 s1 ) > > data Thread a = forall b . MkThread (StateT (Thread b) [] a) > > instance Monad Thread where > return = MkThread . return > MkThread p >>= k = MkThread ( do x <- p >let MkThread p' = k x >p' ) > > I got this error : >My brain just exploded. > I can't handle pattern bindings for existentially-quantified constructors. > In the binding group > MkThread p' = k x > In the first argument of `MkThread', namely > `(do > x <- p > let MkThread p' = k x > p')' > In the definition of `>>=': > MkThread (do > x <- p > let MkThread p' = k x > p') > > How can i define (>>=) for my thread monad ? > > Thanks in advance for any piece of advice, > Mathieu > > -- > There are only 10 types of people in the world: > Those who understand binary and those who don't. > ___ > Glasgow-haskell-users mailing list > [EMAIL PROTECTED] > http://www.haskell.org/mailman/listinfo/glasgow-haskell-users > ___ Glasgow-haskell-users mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
brain explosion in polymorphic state monad
Hello, I am trying to define a polymorphic state monad using glasgow extensions and I got a brain explosion of ghc when i try to compile it. Here is the code : newtype StateT s m a = MkStateT (s -> m (a, s)) instance Monad m => Monad (StateT s m) where return x = MkStateT (\s -> return (x, s)) MkStateT m1 >>= k = MkStateT (\s0 -> do (a, s1) <- m1 s0 let MkStateT m2 = k a m2 s1 ) data Thread a = forall b . MkThread (StateT (Thread b) [] a) instance Monad Thread where return = MkThread . return MkThread p >>= k = MkThread ( do x <- p let MkThread p' = k x p' ) I got this error : My brain just exploded. I can't handle pattern bindings for existentially-quantified constructors. In the binding group MkThread p' = k x In the first argument of `MkThread', namely `(do x <- p let MkThread p' = k x p')' In the definition of `>>=': MkThread (do x <- p let MkThread p' = k x p') How can i define (>>=) for my thread monad ? Thanks in advance for any piece of advice, Mathieu -- There are only 10 types of people in the world: Those who understand binary and those who don't. ___ Glasgow-haskell-users mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
non-termination during compilation
Hi, the following example causes ghc to loop (or run rather long): --- snip --- data U = MkU (U -> Bool) russel :: U -> Bool russel u@(MkU p) = not $ p u x :: Bool x = russel (MkU russel) --- snip --- I think, a compiler should always terminate, shouldn't it!? Compilation succeeds for "russel $ MkU russel" instead of "russel (MkU russel)". (Surely, x is bottom and therefore the example is senseless) Regards Christian ___ Glasgow-haskell-users mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: ObjectIO Library
Hi there, leaving it out of the 5.04.1 installer was unintended, esp. since 5.04 had it included. I'll make sure it makes a re-appearance in 5.04.2 (or whatever the next GHC release ends up being named.) --sigbjorn - Original Message - From: Alfonso To: [EMAIL PROTECTED] Sent: Tuesday, October 08, 2002 09:03 Subject: ObjectIO Library Hello: I have the information that The library ObjectIO is included in the ghc.5.0.4 version, unfortunately I download the msi file for windows (ghc-5-04-1.msi) and the library does not appear in the imports directory after the installation. Have I the wrong information? Do I need to download another msi ? How can I use objectIO with version 5.04.1? thank you Alfonso ___ Glasgow-haskell-users mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: ghc --make and static libraries (SOLUTION)
tor 2002-10-10 klockan 14.02 skrev Martin Norbäck: > How do I go about linking to a static library when using --make? > > If i do > > ghc --make Module libmodulelib.a > > then ghc syas: > > chasing modules from Module,libmodulelib.a and complains about not being > able to find the _module_ modulelib.a. Likewise on windows, if I do > > ghc --make Module modulelib.dll > > it also complains about not finding the _module_ modulelib.dll. > > If I specify the object files that makes up modulelib then there are no > complaints, likewise, if I link without --make, ghc uses the library > just fine. > > Is this the intended behaviour, and if it is, how do I go about linking > with libraries when using --make? Thanks for those who replied. I found a solution: use -optllibmodulelib.a and -optmodulelib.dll and they will be ignored and just passed on to the linker as they should be. Regards, Martin signature.asc Description: Detta =?ISO-8859-1?Q?=E4r?= en digitalt signeradmeddelandedel
RE: ObjectIO Library
I have the information that The library ObjectIO is included in the ghc.5.0.4 version, unfortunately I download the msi file for windows (ghc-5-04-1.msi) and the library does not appear in the imports directory after the installation. Have I the wrong information? Do I need to download another msi ? How can I use objectIO with version 5.04.1? The message below is the most recent I know about for ObjectIO. It’s not yet included as a standard part of the GHC distribution, though I hope it will become so in due course. Simon -Original Message- From: Krasimir Angelov [mailto:[EMAIL PROTECTED]] Sent: 04 September 2002 19:01 To: haskell Cc: [EMAIL PROTECTED] Subject: ANN: ObjectIO update for GHC-5.04 Hi, Haskellers An update is available for ObjectIO for GHC-5.04. Just extract the package over the GHC directory to update the library. More information: http://haskell.cs.yale.edu/ObjectIO This is the package: http://haskell.cs.yale.edu/ObjectIO/ObjectIO_update.zip Krasimir
ghc --make and static libraries
How do I go about linking to a static library when using --make? If i do ghc --make Module libmodulelib.a then ghc syas: chasing modules from Module,libmodulelib.a and complains about not being able to find the _module_ modulelib.a. Likewise on windows, if I do ghc --make Module modulelib.dll it also complains about not finding the _module_ modulelib.dll. If I specify the object files that makes up modulelib then there are no complaints, likewise, if I link without --make, ghc uses the library just fine. Is this the intended behaviour, and if it is, how do I go about linking with libraries when using --make? Regards, Martin signature.asc Description: Detta =?ISO-8859-1?Q?=E4r?= en digitalt signeradmeddelandedel
Re: Building Both "Regular" and "Profiling" Libraries
At 2002-10-10 01:23, Ketil Z. Malde wrote: >Ashley Yakeley <[EMAIL PROTECTED]> writes: > >> I did notice that for -osuf you seem to need the '.' but for -hisuf you >> don't... > >Weird, I've never seen that behavior (GHC 5.02 and 5.04, x86-Linux and >Sparc-Solaris). I just checked with 5.04 on my Linux box, and 5.02 on >a Sun, just to make sure. > >What system and compiler version are you using? My mistake, I'm using -o, which overrides -osuf... -- Ashley Yakeley, Seattle WA ___ Glasgow-haskell-users mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Building Both "Regular" and "Profiling" Libraries
Ashley Yakeley <[EMAIL PROTECTED]> writes: > I did notice that for -osuf you seem to need the '.' but for -hisuf you > don't... Weird, I've never seen that behavior (GHC 5.02 and 5.04, x86-Linux and Sparc-Solaris). I just checked with 5.04 on my Linux box, and 5.02 on a Sun, just to make sure. What system and compiler version are you using? -kzm -- If I haven't seen further, it is by standing in the footprints of giants ___ Glasgow-haskell-users mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
