- Glasgow-haskell-users

could not find link destinations
by Wolfgang Jeltsch 03 Oct '08

03 Oct '08

Hello, I built GHC 6.10.0.20080927 on Debian GNU/Linux for i386. At the end of the build process I got numerous warnings of the form “could not find link destinations for: […]”. Is this intensional? Best wishes, Wolfgang

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Re: planning for ghc-6.10.1 and hackage
by Duncan Coutts 02 Oct '08

02 Oct '08

On Wed, 2008-10-01 at 23:35 -0600, humasect wrote: > Duncan, > > > Since nothing (relatively) is dependant on base 4, why not call it > 'base-4' ? Or hide it like 'ghc' and some other packages are hidden > from inclusion when not explicitly referenced. It is called base-4, it's name is base and the version number is 4. I think what you're asking is why we do not call it "base4-0" or something and the reason is because that looses the connection between versions of packages. Though on the plus side it'd force everyone to specify a major api version, but the right way to do that is to require closed version ranges on base in .cabal files (and other packages that follow the package versioning policy) > Or.. in theory if someone or something can go through all cabal and > add "&& base < 4" through a Hackage filter? <- my apologies I am not > that knowledgeable, but this is what I did for example with my project > that uses storablevector. Yes, that would work if every package on hackage were updated or if we could adjust the .cabal file for every package. Well, it would work for runghc Setup configure, the automatic dependency resolver in cabal-install would still need fixing if we want to continue using that. Don and I have spent the last 6 hours discussing the problem and we are now at the stage where we think it might be solvable. I'm going to work on it all day tomorrow and we'll see where we can get. Duncan

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Inferred type is less polymorphic than expected, depends on order
by Jason Dagit 02 Oct '08

02 Oct '08

I was wondering if someone could help me understand why reording the case statements changes the type inference for this code. 1) I find the error message a bit confusing. 2) I don't understand why it's a problem in one order and not the other. I've tried to send this as literate haskell in hopes that you can just copy and paste to a file and run the example. This happens with or without GADTs, this version doesn't have them but they don't turn out to make any difference. \begin{code} {-# LANGUAGE ExistentialQuantification, RankNTypes #-} module Main where data Sealed a = forall x. Sealed (a x) -- Or equivalently: -- data Sealed a where -- Sealed :: a x -> Sealed a \end{code} Originally, I noticed this in a monad context...The original was much more complicated. But, we can simplify it even more, so keep reading. goodOrder :: Monad m => (forall y z. p x y -> q y z -> q x z) -> m (Sealed (p x)) -> (forall b. m (Sealed (q b))) -> m (Sealed (q x)) goodOrder f mx my = do Sealed x <- mx Sealed y <- my return (Sealed (f x y)) badOrder :: Monad m => (forall y z. p x y -> q y z -> q x z) -> m (Sealed (p x)) -> (forall b. m (Sealed (q b))) -> m (Sealed (q x)) badOrder f mx my = do Sealed y <- my Sealed x <- mx return (Sealed (f x y)) Several helpful people in #haskell helped me converge on this greatly simplified version below. \begin{code} f :: p x y -> q y z -> q x z f = undefined \end{code} \begin{code} badOrder :: (Sealed (p x)) -> (forall b. (Sealed (q b))) -> (Sealed (q x)) badOrder sx sy = case sy of Sealed y -> case sx of Sealed x -> Sealed (f x y) \end{code} \begin{code} goodOrder :: (Sealed (p x)) -> (forall b. (Sealed (q b))) -> (Sealed (q x)) goodOrder sx sy = case sx of Sealed x -> case sy of Sealed y -> Sealed (f x y) \end{code} \begin{code} main = return () \end{code} This gives the error: $ ghc --make Reorder.lhs [1 of 1] Compiling Main ( Reorder.lhs, Reorder.o ) Reorder.lhs:52:29: Inferred type is less polymorphic than expected Quantified type variable `x' is mentioned in the environment: y :: q x x1 (bound at Reorder.lhs:51:24) When checking an existential match that binds x :: p x2 x The pattern(s) have type(s): Sealed (p x2) The body has type: Sealed (q x2) In a case alternative: Sealed x -> Sealed (f x y) In the expression: case sx of Sealed x -> Sealed (f x y) After discussing this a bit, I think what may be happening in the badOrder case is that the existentially bound type of x is bound after the type `b' in the type of y, leading to the error message. I would appreciate help understanding this, even if the help is, "Go read paper X, Y, and Z." Thanks! Jason

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GHC on Solaris/SPARC?
by Elliott Slaughter 01 Oct '08

01 Oct '08

Hi, I am having trouble with precompiled binary http://www.haskell.org/ghc/dist/6.8.3/maeder/ghc-6.8.3-sparc-sun-solaris2.t… . My first problem was that the machine is 64-bit SPARC while the binary seems to be 32-bit. Since the dynamically linked GHC binary requires additional .so files to run, any libs which I try to compile on the machine itself run into ELF class incompatibility errors. So I tried installing prebuilt packages from http://sunfreeware.com/, and spent a couple hours grokking the Solaris package system before I figured out how to extract the right files. Now I think I have the right libs installed, but when I try to run GHC, I get this: -bash-3.00$ runhaskell Setup configure ld.so.1: ghc-6.8.3: fatal: relocation error: file /home/.../lib/libncurses.so.5: symbol main: referenced symbol not found (FYI, I got ncurses 5.6 from http://sunfreeware.com/programlistsparc10.html#ncurses.) Any suggestions would be welcome, thanks in advance. -- Elliott Slaughter "Any road followed precisely to its end leads precisely nowhere." - Frank Herbert -- Elliott Slaughter "Any road followed precisely to its end leads precisely nowhere." - Frank Herbert

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Re: ANNOUNCE: GHC 6.10.1 beta
by humasect 30 Sep '08

30 Sep '08

Thank you all. Everything is great now. It was because (Just ghcPath) was not passed into runGhc, and lack of ghc-path. peace and happiness, -lyndon 2008/9/28 Thorkil Naur <naur(a)post11.tele.dk> Hello, > > On Sunday 28 September 2008 19:27, humasect wrote: > > Ah, indeed it does! Then, more about GHC API: > > "Shell: Shell: missing -B<dir> option" > > > > I can't find any information of what this -B is, it is not in GHC sources > or > > anything helpful from google. > > The -B is used from a ghc shell script to identify where the rest of the > GHC > installation resides. An example with a GHC 6.8.2 installed in > $HOME/tn/install/ghc-6.8.2: > > > tn@linux:~> cat tn/install/ghc-6.8.2/bin/ghc > > #!/bin/sh > > GHCBIN=/home/tn/tn/install/ghc-6.8.2/lib/ghc-6.8.2/ghc-6.8.2 > > TOPDIROPT=-B/home/tn/tn/install/ghc-6.8.2/lib/ghc-6.8.2 > > exec $GHCBIN $TOPDIROPT ${1+"$@"} > > tn@linux:~> > > There is likely some designation for this option that I cannot recall. If > it > is documented anywhere, I haven't noticed. > > > ... > > Best regards > Thorkil >

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Re: newSession gone from GHC API
by humasect 29 Sep '08

29 Sep '08

Also to make Located String in the simple way: import SrcLoc L noSrcSpan "-hidir ../build" also make sure to "import MonadUtils" for that version of liftIO. I have converted the graphical/opengl/openal shell for the project I am working on successfully, let me know if you have questions! -lyndon 2008/9/29 Claus Reinke <claus.reinke(a)talk21.com> I just noticed that newSession has been removed from the GHC API. >> Unfortunately, this breaks nearly all examples on the web: >> http://www.haskell.org/haskellwiki/GHC/As_a_library >> http://hackage.haskell.org/trac/ghc/wiki/Commentary/Compiler/API >> Could someone fix those up, to show the new style of interaction? Also >> are the breaking changes to newSession in GHC 6.10, or only in GHC Head? >> > > Thomas said he was working on a conversion guide, but > delayed by travelling: > > http://www.haskell.org/pipermail/cvs-ghc/2008-September/045361.html > > Meanwhile, since you're somewhat familar with haddock, his > patches to port haddock to the new api may help (I used them > to figure out where to look for more info;). Or, if you prefer > smaller examples, have a look at > > http://www.cs.kent.ac.uk/~cr3/toolbox/haskell/syb-utils/examples/GhcApiSybT… > > which I patched recently (diff below). Mostly, you'll be looking for > runGhc, dropping session parameters, changing dynamic flags from > String to Located String, and splitting checkModule into separate > phases (there's a class that simplifies access via the old record selector > functions). Possibly other small things, like using liftIO to > do IO in the Ghc monads. > > Hth, > Claus > > $ darcs changes -v -p 'new Ghc Api' | sed 's/\[_.._\]\[_._\]$//' > diffing dir... > Mon Sep 22 20:01:02 GMT Daylight Time 2008 claus.reinke(a)talk21.com > * adapt example to new Ghc Api > { > hunk ./examples/GhcApiSybTesting.hs 15 > +import SrcLoc > +import MonadUtils > hunk ./examples/GhcApiSybTesting.hs 35 > -main = defaultErrorHandler defaultDynFlags $ do > - s <- newSession (Just libdir) > - flags <- getSessionDynFlags s > - (flags,_,_) <- parseDynamicFlags flags ["-package ghc"] > +main = defaultErrorHandler defaultDynFlags $ > + runGhc (Just libdir) $ do > + flags <- getSessionDynFlags > + (flags,_,_) <- parseDynamicFlags flags [noLoc "-package ghc"] > hunk ./examples/GhcApiSybTesting.hs 40 > - setSessionDynFlags s flags{ hscTarget=HscInterpreted } > - addTarget s =<< guessTarget source Nothing > - load s LoadAllTargets > - unqual <- getPrintUnqual s > + setSessionDynFlags flags{ hscTarget=HscInterpreted } > + addTarget =<< guessTarget source Nothing > + load LoadAllTargets > + unqual <- getPrintUnqual > + {- > hunk ./examples/GhcApiSybTesting.hs 50 > + -} > + tcm <- typecheckModule =<< parseModule (mkModuleName modName) > + doSomething unqual tcm > hunk ./examples/GhcApiSybTesting.hs 63 > - doSomething unqual cm = do > - let parsed = parsedSource cm > - renamed = renamedSource cm > - typechecked = typecheckedSource cm > + doSomething unqual tcm = liftIO $ do > + let parsed = parsedSource tcm > + renamed = renamedSource tcm > + typechecked = typecheckedSource tcm > hunk ./examples/GhcApiSybTesting.hs 84 > - maybe (putStrLn "no typechecked source") > - (printForUser stdout unqual . shown TypeChecker) > typechecked > + printForUser stdout unqual $ shown TypeChecker typechecked > > } > > _______________________________________________ > Glasgow-haskell-users mailing list > Glasgow-haskell-users(a)haskell.org > http://www.haskell.org/mailman/listinfo/glasgow-haskell-users >

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GADTs and functional dependencies
by Wolfgang Jeltsch 29 Sep '08

29 Sep '08

Hello, please consider the following code: > {-# LANGUAGE GADTs, MultiParamTypeClasses, FunctionalDependencies #-} > > data GADT a where > > GADT :: GADT () > > class Class a b | a -> b > > instance Class () () > > fun :: (Class a b) => GADT a -> b > fun GADT = () I’d expect this to work but unfortunately, using GHC 6.8.2, it fails with the following message: > FDGADT.hs:12:11: > Couldn't match expected type `b' against inferred type `()' > `b' is a rigid type variable bound by > the type signature for `fun' at FDGADT.hs:11:16 > In the expression: () > In the definition of `fun': fun GADT = () What’s the reason for this? Is there a workaround? Does this work in 6.8.3 or 6.10.1? Thank you in advance. Best wishes, Wolfgang

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6.10-candidate tested
by Serge D. Mechveliani 29 Sep '08

29 Sep '08

Dear GHC developers, I have tested ghc-6.10.0.20080921 on * making it by ghc-6.8.2, * making it by itself, * the DoCon and Dumatel applications. It looks all right. Regards, ----------------- Serge Mechveliani mechvel(a)botik.ru

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newSession gone from GHC API
by Mitchell, Neil 29 Sep '08

29 Sep '08

Hi I just noticed that newSession has been removed from the GHC API. Unfortunately, this breaks nearly all examples on the web: http://www.haskell.org/haskellwiki/GHC/As_a_library http://hackage.haskell.org/trac/ghc/wiki/Commentary/Compiler/API Could someone fix those up, to show the new style of interaction? Also are the breaking changes to newSession in GHC 6.10, or only in GHC Head? Thanks Neil ============================================================================== Please access the attached hyperlink for an important electronic communications disclaimer: http://www.credit-suisse.com/legal/en/disclaimer_email_ib.html ==============================================================================

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Re: ANNOUNCE: GHC 6.10.1 beta
by humasect 28 Sep '08

28 Sep '08

uh oh.. ~/Haskell/bin/ghc +RTS -N2 -RTS -hidir ../build/ -odir ../build/ -threaded -package ghc -main-is Shell --make Shell -DCALLCONV=ccall [4 of 4] Compiling Shell ( Shell.hs, ../build/Shell.o ) Linking Shell ... ld: atom sorting error for _ghczm6zi10zi0zi20080927_LibFFI_Czuffizutype_closure_tbl and _ghczm6zi10zi0zi20080927_LibFFI_Czuffizucif_closure_tbl in /Users/humasect/Haskell/lib/ghc-6.10.0.20080927/ghc-6.10.0.20080927/libHSghc-6.10.0.20080927.a(LibFFI.o) ld: atom sorting error for _ghczm6zi10zi0zi20080927_LibFFI_Czuffizutype_closure_tbl and _ghczm6zi10zi0zi20080927_LibFFI_Czuffizucif_closure_tbl in /Users/humasect/Haskell/lib/ghc-6.10.0.20080927/ghc-6.10.0.20080927/libHSghc-6.10.0.20080927.a(LibFFI.o) When linking with new GHC api after converting this shell to use it ( http://hackage.haskell.org/trac/ghc/wiki/GhcApiStatus) -lyndon

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