Re: [Haskell-cafe] Re: POSIX AIO (asych I/O) ...
On 2008 Jul 2, at 1:42, Galchin, Vasili wrote: errno - throwErrnoIfMinus1 aioError (c_aio_error p_aiocb) ghc thinks that Errno should be an instance of Num: System/Posix/Aio.hsc:117:15: No instance for (Num Errno) I expect so it can compare it to -1(throwErrnoIfMinusOne). But if the return value is actually an errno and not -1 to indicate error (which it is if I read the manpage correctly), you don't want throwErrnoIfMinus1 anyway; I suspect you want to wrap the return value of c_aio_return (which should be IO CInt) in an Errno constructor, then use errnoToIOError if you really want to raise an IOError. (What were you expecting for count? I see none, just an errno.) Note that it *never* returns -1; it returns 0 for successful completion for the aiocb, EINPROGRESS if it's still working, and the appropriate errno if it failed. You might want to decide if you want to use the aio_return style interface or something more Haskell-ish before designing this part of the API. If you want to stick close to the C interface: aioReturn :: AIOCB - IO (AIOCB, Errno) aioReturn aiocb = do allocaBytes (#const sizeof(struct aiocb)) $ \ p_aiocb - do poke p_aiocb aiocb err - c_aio_return p_aiocb aiocb - peek p_aiocb return (aiocb, Errno err) I'd actually consider something more Haskellish, e.g. a variant of StateT IO where the state is the aiocb and errno, the errno initialized to eINPROGRESS and set by aioReturn and aioError (and once aioReturn is called, it can't be called again so return the cached value if needed). -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] [EMAIL PROTECTED] system administrator [openafs,heimdal,too many hats] [EMAIL PROTECTED] electrical and computer engineering, carnegie mellon universityKF8NH ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: POSIX AIO (asych I/O) ...
On Wed, 2008-07-02 at 02:07 -0400, Brandon S. Allbery KF8NH wrote: On 2008 Jul 2, at 1:42, Galchin, Vasili wrote: errno - throwErrnoIfMinus1 aioError (c_aio_error p_aiocb) ghc thinks that Errno should be an instance of Num: System/Posix/Aio.hsc:117:15: No instance for (Num Errno) I expect so it can compare it to -1(throwErrnoIfMinusOne). But if the return value is actually an errno and not -1 to indicate error (which it is if I read the manpage correctly), you don't want throwErrnoIfMinus1 anyway; I suspect you want to wrap the return value of c_aio_return (which should be IO CInt) in an Errno constructor, then use errnoToIOError if you really want to raise an IOError. (What were you expecting for count? I see none, just an errno.) Note that it *never* returns -1; it returns 0 for successful completion for the aiocb, EINPROGRESS if it's still working, and the appropriate errno if it failed. It seems as though it can return -1 if given non-sensical input. But in that case, the nicely type-correct thing to do would still be to have the C binding return a CInt, and wrap that after the call to throwErrnoIfMinus1 (in this case, `errno' still refers to the global errno, set to EINVAL). jcc ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: POSIX AIO (asych I/O) ...
On 2008 Jul 2, at 2:15, Jonathan Cast wrote: It seems as though it can return -1 if given non-sensical input. But in The POSIX spec says it returns EINVAL in that case. -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] [EMAIL PROTECTED] system administrator [openafs,heimdal,too many hats] [EMAIL PROTECTED] electrical and computer engineering, carnegie mellon universityKF8NH ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: POSIX AIO (asych I/O) ...
On Wed, 2008-07-02 at 02:17 -0400, Brandon S. Allbery KF8NH wrote: On 2008 Jul 2, at 2:15, Jonathan Cast wrote: It seems as though it can return -1 if given non-sensical input. But in The POSIX spec says it returns EINVAL in that case. Are you sure? A little googling picks up e.g. HP docs [1] that state RETURN VALUE If the aiocb is invalid or if no asynchronous I/O operation is enqueued for the aiocb, aio_error() returns -1 and errno is set to indicate the error It may be non-POSIX, but I'd like to see some verbiage for which HP/UX's behavior isn't the most natural interpretation. jcc [1] http://docs.hp.com/en/B9106-90009/aio_error.2.html ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: POSIX AIO (asych I/O) ...
Thanks, Brandon!! I understand most of what you say but let me ponder! Kind regards, Vasili On Wed, Jul 2, 2008 at 1:07 AM, Brandon S. Allbery KF8NH [EMAIL PROTECTED] wrote: On 2008 Jul 2, at 1:42, Galchin, Vasili wrote: errno - throwErrnoIfMinus1 aioError (c_aio_error p_aiocb) ghc thinks that Errno should be an instance of Num: System/Posix/Aio.hsc:117:15: No instance for (Num Errno) I expect so it can compare it to -1(throwErrnoIfMinusOne). But if the return value is actually an errno and not -1 to indicate error (which it is if I read the manpage correctly), you don't want throwErrnoIfMinus1 anyway; I suspect you want to wrap the return value of c_aio_return (which should be IO CInt) in an Errno constructor, then use errnoToIOError if you really want to raise an IOError. (What were you expecting for count? I see none, just an errno.) Note that it *never* returns -1; it returns 0 for successful completion for the aiocb, EINPROGRESS if it's still working, and the appropriate errno if it failed. You might want to decide if you want to use the aio_return style interface or something more Haskell-ish before designing this part of the API. If you want to stick close to the C interface: aioReturn :: AIOCB - IO (AIOCB, Errno) aioReturn aiocb = do allocaBytes (#const sizeof(struct aiocb)) $ \ p_aiocb - do poke p_aiocb aiocb err - c_aio_return p_aiocb aiocb - peek p_aiocb return (aiocb, Errno err) I'd actually consider something more Haskellish, e.g. a variant of StateT IO where the state is the aiocb and errno, the errno initialized to eINPROGRESS and set by aioReturn and aioError (and once aioReturn is called, it can't be called again so return the cached value if needed). -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] [EMAIL PROTECTED] system administrator [openafs,heimdal,too many hats] [EMAIL PROTECTED] electrical and computer engineering, carnegie mellon universityKF8NH ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Haskell on ARM (was Re: ANN: Topkata)
Thanks for sharing your experences. I just tried to port GHC 6.8.3 to my TI Davincci (c6446) board by following the GHC Wiki Building/Porting page [1]. Both arm-compile and cross-compile version have failed unfortunately. So, I turn to try compile an local GHC on linux. It takes me so many time. I can not finish building it before off work. [1] http://hackage.haskell.org/trac/ghc/wiki/Building/Porting#PortingGHCtoanewplatform -- L.Guo 2008-07-02 - From: Jeremy Shaw At: 2008-06-28 02:57:38 Subject: Re: [Haskell-cafe] Re: Haskell on ARM (was Re: ANN: Topkata) Cool! By cross-compilation, I assume you mean, a version of GHC which runs on x86, but generates ARM assembly? Another option might be to use a nintendo DS emulator which has been configured to support more RAM and CPU power ? A true cross-compiler would be nice though, because it will run much faster. GHC does have some support for cross-compilation, but in the current implementation, it is mostly (entirely?) there for bootstrapping. I have no idea how the ghc backend rewrite for 6.10 will affect this. Hope this helps, j. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Question about abstraction
Dear list, I have I question about the following code I was playing with: (you can past the following right into your editor) -- import Data.Foldable (Foldable, foldMap) import Data.Monoid (mempty, mappend) import Data.Traversable(Traversable, traverse) import Control.Applicative (pure, ($), (*)) -- I was playing with the following tree-like datastructure (my plan -- is to make some kind of kd-tree but that's not important now): data T a = L | N C2 a (T a) (T a) (T a) (T a) type C2 = (Float, Float) -- A fold always comes in handy: foldT :: b - (C2 - a - b - b - b - b - b) - T a - b foldT e _ L = e foldT e n (N c x tl tr bl br) = n c x (foldT e n tl) (foldT e n tr) (foldT e n bl) (foldT e n br) instance Functor T where fmap f = foldT L (\p - N p . f) -- Now I defined the following instances: instance Foldable T where foldMap f = foldT mempty $ \_ x tl tr bl br - f x `mappend` tl `mappend` tr `mappend` bl `mappend` br instance Traversable T where traverse f = foldT (pure L) $ \p x tl tr bl br - N p $ f x * tl * tr * bl * br -- -- If you look at the previous two functions you see a similar pattern: -- they both combine an initial value: 'f x' and 'N p $ f x' respectively -- with the childs using a combining function: 'mappend' and '*' respectively. -- My question is: can I abstract from that? -- It looks like I can using a function like: combineWith :: b - (b - a - b) - a - a - a - a - b n `combineWith` f = \tl tr bl br - n `f` tl `f` tr `f` bl `f` br -- Now 'foldMap' becomes: instance Foldable T where foldMap f = foldT mempty $ \_ x - f x `combineWith` mappend -- But 'traverse' won't typecheck: instance Traversable T where traverse f = foldT (pure L) $ \p x - (N p $ f x) `combineWith` (*) -- Is it possible to make 'combineWith' more general so that the -- previous typechecks (maybe using arbitrary-rank polymorphism but I -- don't see how)? -- Thanks, Bas van Dijk ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: POSIX AIO (asych I/O) ...
On 2008 Jul 2, at 2:32, Jonathan Cast wrote: On Wed, 2008-07-02 at 02:17 -0400, Brandon S. Allbery KF8NH wrote: On 2008 Jul 2, at 2:15, Jonathan Cast wrote: It seems as though it can return -1 if given non-sensical input. But in The POSIX spec says it returns EINVAL in that case. Are you sure? A little googling picks up e.g. HP docs [1] that state Hm. I think the manuals I was looking at are ambiguous on the point, and I can't get at the actual standard right now. Probably best to assume -1/EINVAL is a possible return value, then. -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] [EMAIL PROTECTED] system administrator [openafs,heimdal,too many hats] [EMAIL PROTECTED] electrical and computer engineering, carnegie mellon universityKF8NH ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: A Monad for on-demand file generation?
hen, the readFileOD could put the timestamp of the read file in a Monad-local state and the writeFileOD could, if the output is newer then all inputs listed in the state, skip the writing and thus the unsafeInterleaveIO’ed file reads are skipped as well, if they were not required for deciding the flow of the program. How is your system similar to make/Makefile or different to make/Makefile ? Are your actions more restricted? Are the semantics more imperative? Are the dependencies still explicit or are them implicit and inferred? -- Chris ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Unboxed array of product type - product type of unboxed arrays
Hi, I'm trying to extended the standard unboxed array types and array classes to my own product types, for now let's just say (,). So if the proper MArray and IArray instances exist for e and f, then I can make an instance for (e,f). The actual type of that array, something like (UArray i e, UArray i f), would be given by an associated type. This is how the uvector library does it, but that library defines its own array primitives and classes. I'd like to reuse the standard ones if possible. The problem I keep running into is the kind of the array, * - * - *, or 'a i e'. The crucial type there is e, which is used to dispatch the instance to the proper associated type, so if e = (a,b) then the array type would be (UArray i a, UArray I b), and if e is (a,b,c) then (UArray i a, UArray i b, UArray i c). If IArray was instead expecting the array type to be 'a e i' I could maybe do something like this: class UArrClass e where data UArr e :: * - * instance (IArray UArray e, IArray UArray f) = UArrClass (e,f) where data UArr (e,f) i = UArrPair (UArray i e) (UArray i f) But as it stands, I can't do that. The 'i' type parameter has to be bound as a parameter of UArrClass. So instead I tried this. class UArrClass i e where data UArr i e unsafeAt_ :: UArr i e - Int - e --mirror all IArray methods instance ( IArray UArray e , IArray UArray f , Ix i --needed for unsafeAt ) = UArrClass i (e,f) where newtype UArr i (e,f) = UArrPair (UArray i e) (UArray i f) unsafeAt_ (UArrPair ea fa) i = (unsafeAt ea i , unsafeAt fa i) and then the instance for IArray could be defined as follows, just a mapping from the methods of that class onto my own: instance ( IArray UArray e , IArray UArray f , UArrClass i (e,f) ) = IArray UArr (e,f) where unsafeAt = unsafeAt_ The problem I get now is from the 'Ix i' context of the IArray methods. The 'i' there is only mentioned in the context of the methods, not the class, so I have no 'handle' onto that 'i' that I can use to explicitly unify it with the 'i' mentioned in UArrClass. The compiler keeps complaining about rigid type variables. It would be great if I could leave that type variable unbound in my class, and only bind it in the methods, as IArray does, but as far as I can tell, I can't. I need to bind 'i' in my class because it's the first type-argument to the array type constructor, rather than the second. I don't care about the 'i', its the 'e' I'm after, but all applications of the associated type constructor need to be saturated. Can anyone see a way to do this? I understand there's about a million other ways to accomplish what I'm trying to do without IArray and MArray, but I'm just wondering if I should abandon those classes altogether, and use my own array classes, using something like uvector or unsafeIO/ForeignPtr. That seems to be trend. Thanks, Scott ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Haskell on ARM (was Re: ANN: Topkata)
Could we start documenting this on the wiki ? It will be interesting to keep track of what we have tried, what attempts failed and why. -- Don leaveye.guo: Thanks for sharing your experences. I just tried to port GHC 6.8.3 to my TI Davincci (c6446) board by following the GHC Wiki Building/Porting page [1]. Both arm-compile and cross-compile version have failed unfortunately. So, I turn to try compile an local GHC on linux. It takes me so many time. I can not finish building it before off work. [1] http://hackage.haskell.org/trac/ghc/wiki/Building/Porting#PortingGHCtoanewplatform -- L.Guo 2008-07-02 - From: Jeremy Shaw At: 2008-06-28 02:57:38 Subject: Re: [Haskell-cafe] Re: Haskell on ARM (was Re: ANN: Topkata) Cool! By cross-compilation, I assume you mean, a version of GHC which runs on x86, but generates ARM assembly? Another option might be to use a nintendo DS emulator which has been configured to support more RAM and CPU power ? A true cross-compiler would be nice though, because it will run much faster. GHC does have some support for cross-compilation, but in the current implementation, it is mostly (entirely?) there for bootstrapping. I have no idea how the ghc backend rewrite for 6.10 will affect this. Hope this helps, j. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Unboxed array of product type - product type of unboxed arrays
Am Mittwoch, 2. Juli 2008 18:48 schrieb Scott Dillard: Hi, I'm trying to extended the standard unboxed array types and array classes to my own product types, for now let's just say (,). So if the proper MArray and IArray instances exist for e and f, then I can make an instance for (e,f). The actual type of that array, something like (UArray i e, UArray i f), would be given by an associated type. This is how the uvector library does it, but that library defines its own array primitives and classes. I'd like to reuse the standard ones if possible. The problem I keep running into is the kind of the array, * - * - *, or 'a i e'. The crucial type there is e, which is used to dispatch the instance to the proper associated type, so if e = (a,b) then the array type would be (UArray i a, UArray I b), and if e is (a,b,c) then (UArray i a, UArray i b, UArray i c). If IArray was instead expecting the array type to be 'a e i' I could maybe do something like this: class UArrClass e where data UArr e :: * - * instance (IArray UArray e, IArray UArray f) = UArrClass (e,f) where data UArr (e,f) i = UArrPair (UArray i e) (UArray i f) But as it stands, I can't do that. The 'i' type parameter has to be bound as a parameter of UArrClass. So instead I tried this. class UArrClass i e where data UArr i e unsafeAt_ :: UArr i e - Int - e --mirror all IArray methods Perhaps class (Ix i) = UArrClass i e where ... would work? instance ( IArray UArray e , IArray UArray f , Ix i --needed for unsafeAt ) = UArrClass i (e,f) where newtype UArr i (e,f) = UArrPair (UArray i e) (UArray i f) unsafeAt_ (UArrPair ea fa) i = (unsafeAt ea i , unsafeAt fa i) and then the instance for IArray could be defined as follows, just a mapping from the methods of that class onto my own: instance ( IArray UArray e , IArray UArray f , UArrClass i (e,f) ) = IArray UArr (e,f) where unsafeAt = unsafeAt_ The problem I get now is from the 'Ix i' context of the IArray methods. The 'i' there is only mentioned in the context of the methods, not the class, so I have no 'handle' onto that 'i' that I can use to explicitly unify it with the 'i' mentioned in UArrClass. The compiler keeps complaining about rigid type variables. It would be great if I could leave that type variable unbound in my class, and only bind it in the methods, as IArray does, but as far as I can tell, I can't. I need to bind 'i' in my class because it's the first type-argument to the array type constructor, rather than the second. I don't care about the 'i', its the 'e' I'm after, but all applications of the associated type constructor need to be saturated. Can anyone see a way to do this? I understand there's about a million other ways to accomplish what I'm trying to do without IArray and MArray, but I'm just wondering if I should abandon those classes altogether, and use my own array classes, using something like uvector or unsafeIO/ForeignPtr. That seems to be trend. Thanks, Scott ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Unboxed array of product type - product type of unboxed arrays
On Wed, Jul 2, 2008 at 11:52 AM, Daniel Fischer [EMAIL PROTECTED] wrote: Perhaps class (Ix i) = UArrClass i e where ... would work? class Ix i = UArrClass i e where data UArr i e unsafeAt_ :: UArr i e - Int - e instance ( IArray UArray e , IArray UArray f , Ix i ) = UArrClass i (e,f) where newtype UArr i (e,f) = UArrPair (UArray i e) (UArray i f) unsafeAt_ (UArrPair ea fa) i = (unsafeAt ea i , unsafeAt fa i) instance ( IArray UArray e , IArray UArray f , UArrClass i (e,f) , Ix i ) = IArray UArr (e,f) where unsafeAt = unsafeAt_ test1 :: UArr Int (Int,Int) - (Int,Int) test1 a = unsafeAt a 5 --this is line 77 Array.hs:77:10: Ambiguous type variable `i' in the constraint: `Ix i' arising from a use of `unsafeAt' at Array.hs:77:10-21 Probable fix: add a type signature that fixes these type variable(s) I think the 'i' there is the one from the method context of IArray, class IArray a e where unsafeAt :: Ix i = a i e - Int - e But that 'i' does not escape to the class context, so I have no way to address it. I think I need to leave it free, but I can't do that with my associated type. Scott ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] GHC ARM Hackathon (Re: Haskell on ARM )
It may not be long before most of the computing world has gone mobile. CNET suggests the major players will be Qualcomm and Intel, where QC is more power-efficient, but Intel conveniently targets x86. June 29, 2008 7:30 PM PDT Qualcomm vs Intel: You decide%20http://news.cnet.com/8301-13924_3-9979989-64.html I'm a software engineer at Qualcomm with a desire to code more Haskell at work. This desire will only get stronger in coming years as multithreaded apps on mobile devices get more popular, and ways to write them reliably in traditional languages continue not to exist. Jeremy Shaw said: Perhaps we should have some sort of GHC on the ARM hackathon when 6.10 comes out Would anybody be interested in a GHC on ARM Hackathon in San Diego this year? When is 6.10 estimated to come out? Do we really need to wait for it? Jeremy Apthorp said: it'll also require that I significantly strip down the runtime system, as the current RTS won't fit in 4M Do you have a plan for how to do this? Maybe we can invite a Simon to teach us the innards of the RTS and help guide us? Thanks, Greg ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: GHC ARM Hackathon (Re: Haskell on ARM )
...try that hyperlink again... Qualcomm vs Intel: You decide http://news.cnet.com/8301-13924_3-9979989-64.html On Wed, Jul 2, 2008 at 11:16 AM, Greg Fitzgerald [EMAIL PROTECTED] wrote: It may not be long before most of the computing world has gone mobile. CNET suggests the major players will be Qualcomm and Intel, where QC is more power-efficient, but Intel conveniently targets x86. June 29, 2008 7:30 PM PDT Qualcomm vs Intel: You decide I'm a software engineer at Qualcomm with a desire to code more Haskell at work. This desire will only get stronger in coming years as multithreaded apps on mobile devices get more popular, and ways to write them reliably in traditional languages continue not to exist. Jeremy Shaw said: Perhaps we should have some sort of GHC on the ARM hackathon when 6.10 comes out Would anybody be interested in a GHC on ARM Hackathon in San Diego this year? When is 6.10 estimated to come out? Do we really need to wait for it? Jeremy Apthorp said: it'll also require that I significantly strip down the runtime system, as the current RTS won't fit in 4M Do you have a plan for how to do this? Maybe we can invite a Simon to teach us the innards of the RTS and help guide us? Thanks, Greg ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: GHC ARM Hackathon (Re: Haskell on ARM )
At Wed, 2 Jul 2008 11:16:18 -0700, Greg Fitzgerald wrote: Would anybody be interested in a GHC on ARM Hackathon in San Diego this year? Definitely. (Conveniently, I live in La Jolla). When is 6.10 estimated to come out? Do we really need to wait for it? According to this Release plan, the plan to release 6.10 around ICFP2008. http://hackage.haskell.org/trac/ghc/wiki/Status/Releases We wouldn't need a final release to get started, just something where the back-end changes are in place and working. One important item from the release plan is: * GHC now uses libffi to implement parts of the FFI, replacing some of the home-grown and very architecture-specific code we had to do this. Amongst other benefits, this will ease the task of porting GHC in the future. And possibly: * Substantial changes to the back end are likely, now that John Dias is here as an intern. John Dias, Simon PJ, Norman Ramsey It sounds like the changes to libffi might already be in 6.9. So, maybe we can start now ? j. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: GHC ARM Hackathon (Re: Haskell on ARM )
Jeremy Shaw wrote: At Wed, 2 Jul 2008 11:16:18 -0700, Greg Fitzgerald wrote: Would anybody be interested in a GHC on ARM Hackathon in San Diego this year? Definitely. (Conveniently, I live in La Jolla). When is 6.10 estimated to come out? Do we really need to wait for it? According to this Release plan, the plan to release 6.10 around ICFP2008. http://hackage.haskell.org/trac/ghc/wiki/Status/Releases We wouldn't need a final release to get started, just something where the back-end changes are in place and working. One important item from the release plan is: * GHC now uses libffi to implement parts of the FFI, replacing some of the home-grown and very architecture-specific code we had to do this. Amongst other benefits, this will ease the task of porting GHC in the future. And possibly: * Substantial changes to the back end are likely, now that John Dias is here as an intern. John Dias, Simon PJ, Norman Ramsey It sounds like the changes to libffi might already be in 6.9. So, maybe we can start now ? j. Unfortunately that's a bit of a reach for me; I live in southern Ontario and will be in New York City from September to December. So, I will likely be unable to attend, though I'll certainly see if I can pull it off. I'd be paying out of pocket for the travel, unfortunately. I definitely want to contribute what I can to this project, both because I want its result and because I want to learn more about GHC and the RTS. As to waiting for 6.10, I won't be able to contribute much work here before late August anyway, by which point much of 6.10 will likely be solidified in the HEAD 6.9. Certainly there are experiments and other parts of the project that can be worked on while waiting for the 6.10 release in late September. I'll post the results of any experiments and any thoughts in the GHC-on-ARM wiki. Notably, a page on what devices the developers have comes to mind. Braden Shepherdson shepheb ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Haskell Weekly News: Issue 75 - July 2, 2008
--- Haskell Weekly News http://sequence.complete.org/hwn/20080702 Issue 75 - July 02, 2008 --- Welcome to issue 75 of HWN, a newsletter covering developments in the [1]Haskell community. Announcements Anglo Haskell 2008. Matthew Sackman [2]announced [3]AngloHaskell 2008, a gathering of all people Haskell-related from beginners, to seasoned hackers to academic giants. All and more are welcomed by large fuzzy green lambdas. The proposed dates and location are Friday the 8th and Saturday the 9th of August, at Imperial College, London. CFP - Special Issue of Fundamenta Informaticae on Dependently Typed Programming. Wouter Swierstra [4]announced a call for papers for a special issue of [5]Fundamenta Informaticae on [6]Dependently Typed Programming. The deadline for submissions is October 1. Gtk2Hs 0.9.13. Peter Gavin [7]announced the release of Gtk2Hs 0.9.13, including bindings for Gnome VFS and GStreamer, a new Gtk+ tutorial adapted by Hans van Thiel, cairo image stride support, and more. Hasim. Jochem Berndsen [8]announced Hasim, a [9]small project to create a library to do discrete event simulation in Haskell, using monads to define a domain-specific language for actions of a process. Galois move. Don Stewart [10]announced that Galois has completed the move of its data center. Expect speedier response times for hackage.haskell.org and darcs.haskell.org. Google Summer of Code Progress updates from participants in the 2008 [11]Google Summer of Code. Hoogle 4. Neil Mitchell (ndm) is working on [12]Hoogle 4. [13]This week, Neil worked on better Haddock database generation, lazy name searching, and a snazzy --info flag for Hoogle. Next up: type search! DPH physics engine. Roman Cheplyaka (Feuerbach) is working on a [14]physics engine using [15]Data Parallel Haskell. [16]This week, he worked on implementing Mirtich's V-Clip algorithm for collision detection (and [17]got it to work), cabalized his project and added documentation. He also ran into an interesting QuickCheck puzzle. Generic tries. Jamie Brandon is working on a library for efficient maps using generalized tries. [18]This week, he created a generic framework for automatically running QuickCheck tests at a number of different types. This week he plans to synthesize the many suggestions from the [19]discussion on the libraries list into a stable API design. Language.C. Benedikt Huber (visq) is [20]working on Language.C, a standalone parser/pretty printer library for C99. [21]This week he worked on a better representation for declarators, and abstracted the notion of an InputStream over both String and ByteString, among other accomplishments. GHC plugins. Max Bolingbroke is working on dynamically loaded plugins for GHC. Cabal dependency framework. Andrea Vezzosi (Saizan) is working on a [22]make-like dependency analysis framework for Cabal. GHC API. Thomas Schilling (nominolo) is working on [23]improvements to the GHC API. Officials at HWN headquarters have released a statement reversing their previous position regarding the existence of Thomas, citing regrettably faulty information to explain their previous misapprehensions. Expect to hear more from Thomas soon, now that he has finished graduating and moving. Libraries Proposals and extensions to the [24]standard libraries. GetOpt formatting improvements. Duncan Coutts [25]proposed some modifications to make the output of the System.Console.GetOpt library more readable, resulting in quite a bit of discussion. HughesPJ improvements. Benedikt Huber [26]proposed a patch with some bug fixes, performance improvements, and QuickCheck test suite for the Text.PrettyPrint.HughesPJ pretty-printing library. Discussion A Monad for on-demand file generation?. Joachim Breitner [27]asked about a monad for transparently tracking files which may need to be regenerated due to dependencies, leading to an interesting discussion of incremental computation, strict vs. lazy I/O, and other issues. New mailing list proposal: Haskell-Edu. Benjamin L. Russell sent out a message [28]proposing a new mailing list hosted at haskell.org, Haskell-Edu: The Haskell Educational Mailing List. The new mailing list would be guided by the principle that Haskell is useful not just in research, but also in teaching programming as part of a liberal arts education. Comments and discussion welcomed. Learning GADT types to simulate dependent types. Paul Johnson is trying to use GADTs to simulate aspects of a dependently typed system, and [29]asks for help improving his Oleg rating. Call graph tool?. C.M.Brown [30]asked whether there is a tool for visualizing the call
[Haskell-cafe] database 101 question
Hello, I have installed the mysql server (mysqld) on my Ubuntu machine. What are the Haskell libraries/components that I will need to write a mysql client?? Kind regards, Vasili ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] calling setWMHints (expects a CInt, I have an Int)
Could someone give me an example of calling setWMHints from
Graphics.X11.Xlib.Extras? The signature is
setWMHints :: Display - Window - WMHints - IO Status
and WMHints is defined as
data WMHints = WMHints {
wmh_flags :: CLong
wmh_input :: Bool
wmh_initial_state :: CInt
wmh_icon_pixmap :: Pixmap
wmh_icon_window :: Window
wmh_icon_x :: CInt
wmh_icon_y :: CInt
wmh_icon_mask :: Pixmap
wmh_window_group :: XID
}
I can't figure out how to convert an Int to a CInt to construct the WMHints
martin
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Re: [Haskell-cafe] calling setWMHints (expects a CInt, I have an Int)
Hi Martin, I can't figure out how to convert an Int to a CInt to construct the WMHints Ask Hoogle: http://haskell.org/hoogle/?q=Int+-%3E+CInt And Hoogle says: toEnum, fromIntegral Thanks Neil ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] calling setWMHints (expects a CInt, I have an Int)
On Wed, Jul 2, 2008 at 2:16 PM, Neil Mitchell [EMAIL PROTECTED] wrote: Hi Martin, I can't figure out how to convert an Int to a CInt to construct the WMHints Ask Hoogle: http://haskell.org/hoogle/?q=Int+-%3E+CInt Nice And Hoogle says: toEnum, fromIntegral thanks a lot :) martin ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] database 101 question
vigalchin: Hello, I have installed the mysql server (mysqld) on my Ubuntu machine. What are the Haskell libraries/components that I will need to write a mysql client?? Check on hackage.haskell.org under the 'database' category. -- Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] database 101 question
Hi Don, I know where to look but I am knew to database architecture. I know there is a driver (whatever that is ... I write device drivers but this is obviously different), backend ??? My question is more generic about what pieces I would need for evenr sqlite3 for example. Vasil On Wed, Jul 2, 2008 at 5:03 PM, Don Stewart [EMAIL PROTECTED] wrote: vigalchin: Hello, I have installed the mysql server (mysqld) on my Ubuntu machine. What are the Haskell libraries/components that I will need to write a mysql client?? Check on hackage.haskell.org under the 'database' category. -- Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] GHC ARM Hackathon (Re: Haskell on ARM )
2008/7/3 Greg Fitzgerald [EMAIL PROTECTED]: Perhaps we should have some sort of GHC on the ARM hackathon when 6.10 comes out Would anybody be interested in a GHC on ARM Hackathon in San Diego this year? I'd be interested, but I live in Sydney, Australia. San Diego's a bit of a stretch :) Jeremy Apthorp said: it'll also require that I significantly strip down the runtime system, as the current RTS won't fit in 4M Do you have a plan for how to do this? Maybe we can invite a Simon to teach us the innards of the RTS and help guide us? I've discussed it briefly with chak (who'll be supervising the project), but as I said, I haven't looked too deeply into the code yet. Jeremy -- - Jem ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] type classes
Hi everyone, I'm working on a computational algebra program and I've run into a problem. In my program, I have types for instances of algebraic objects, e.g. ZModN for modular integers, and types for the objects themselves, e.g. ZModNTy for the ring of modular integers. Now, I want to subclass ZModNTy from something like class RingTy a b where order :: a - Integer units :: a - [b] where `a' represents algebraic object, and `b' the type of instances of that object. I want an instance instance RingTy ZModNTy ZModN where ... but then code that only uses order fails with errors like No instance for (RingTy ZModNTy b) arising from a use of `order' at Test2.hs:16:8-15 since there is no constraint on the second type variable. I think what I really want is class RingTy a where order :: a b - Integer units :: a b - [b] but this doesn't work either since ZModNTy is not parametric in its type like, say, `Polynomial a' is. Is this a common problem? Is there a standard way to handle it? Thank you for your attention, Cotton ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] type classes
On Wednesday 02 July 2008, Cotton Seed wrote: Hi everyone, I'm working on a computational algebra program and I've run into a problem. In my program, I have types for instances of algebraic objects, e.g. ZModN for modular integers, and types for the objects themselves, e.g. ZModNTy for the ring of modular integers. Now, I want to subclass ZModNTy from something like class RingTy a b where order :: a - Integer units :: a - [b] where `a' represents algebraic object, and `b' the type of instances of that object. I want an instance instance RingTy ZModNTy ZModN where ... but then code that only uses order fails with errors like No instance for (RingTy ZModNTy b) arising from a use of `order' at Test2.hs:16:8-15 since there is no constraint on the second type variable. I think what I really want is class RingTy a where order :: a b - Integer units :: a b - [b] but this doesn't work either since ZModNTy is not parametric in its type like, say, `Polynomial a' is. Is this a common problem? Is there a standard way to handle it? Correct me if I'm wrong, but wouldn't the a uniquely determine the b? In that case, you'd probably want a functional dependency: class RingTy a b | a - b where order :: a - Integer units :: a - [b] This solves the problem with order, because with multi-parameter type classes, all the variables should be determined for a use of a method. Since b is not involved with order, it could be anything, so it's rather ambiguous. The functional dependency solves this by uniquely determined b from a, so order is no longer ambiguous. Alternately, with the new type families, this can become: class RingTy a where type RingElem a :: * order :: a - Integer units :: a - [RingElem a] Or something along those lines. Hope that helps. -- Dan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] type classes
Hi Dan, Thanks! This is exactly what I was looking for. Cotton On Wed, Jul 2, 2008 at 9:57 PM, Dan Doel [EMAIL PROTECTED] wrote: On Wednesday 02 July 2008, Cotton Seed wrote: Hi everyone, I'm working on a computational algebra program and I've run into a problem. In my program, I have types for instances of algebraic objects, e.g. ZModN for modular integers, and types for the objects themselves, e.g. ZModNTy for the ring of modular integers. Now, I want to subclass ZModNTy from something like class RingTy a b where order :: a - Integer units :: a - [b] where `a' represents algebraic object, and `b' the type of instances of that object. I want an instance instance RingTy ZModNTy ZModN where ... but then code that only uses order fails with errors like No instance for (RingTy ZModNTy b) arising from a use of `order' at Test2.hs:16:8-15 since there is no constraint on the second type variable. I think what I really want is class RingTy a where order :: a b - Integer units :: a b - [b] but this doesn't work either since ZModNTy is not parametric in its type like, say, `Polynomial a' is. Is this a common problem? Is there a standard way to handle it? Correct me if I'm wrong, but wouldn't the a uniquely determine the b? In that case, you'd probably want a functional dependency: class RingTy a b | a - b where order :: a - Integer units :: a - [b] This solves the problem with order, because with multi-parameter type classes, all the variables should be determined for a use of a method. Since b is not involved with order, it could be anything, so it's rather ambiguous. The functional dependency solves this by uniquely determined b from a, so order is no longer ambiguous. Alternately, with the new type families, this can become: class RingTy a where type RingElem a :: * order :: a - Integer units :: a - [RingElem a] Or something along those lines. Hope that helps. -- Dan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: POSIX AIO (asych I/O) ...
Hi Brandon, Most of what you say makes sense. However, at some places in your narrative aren't you mixing up my aioError and aioReturn?(or aio_error and aio_return, respectively). E.g. aioReturn should return the byte count and not errno? If you want to stick close to the C interface: aioReturn :: AIOCB - IO (AIOCB, Errno) aioReturn aiocb = do allocaBytes (#const sizeof(struct aiocb)) $ \ p_aiocb - do poke p_aiocb aiocb err - c_aio_return p_aiocb aiocb - peek p_aiocb return (aiocb, Errno err) Vasili On Wed, Jul 2, 2008 at 1:07 AM, Brandon S. Allbery KF8NH [EMAIL PROTECTED] wrote: On 2008 Jul 2, at 1:42, Galchin, Vasili wrote: errno - throwErrnoIfMinus1 aioError (c_aio_error p_aiocb) ghc thinks that Errno should be an instance of Num: System/Posix/Aio.hsc:117:15: No instance for (Num Errno) I expect so it can compare it to -1(throwErrnoIfMinusOne). But if the return value is actually an errno and not -1 to indicate error (which it is if I read the manpage correctly), you don't want throwErrnoIfMinus1 anyway; I suspect you want to wrap the return value of c_aio_return (which should be IO CInt) in an Errno constructor, then use errnoToIOError if you really want to raise an IOError. (What were you expecting for count? I see none, just an errno.) Note that it *never* returns -1; it returns 0 for successful completion for the aiocb, EINPROGRESS if it's still working, and the appropriate errno if it failed. You might want to decide if you want to use the aio_return style interface or something more Haskell-ish before designing this part of the API. If you want to stick close to the C interface: aioReturn :: AIOCB - IO (AIOCB, Errno) aioReturn aiocb = do allocaBytes (#const sizeof(struct aiocb)) $ \ p_aiocb - do poke p_aiocb aiocb err - c_aio_return p_aiocb aiocb - peek p_aiocb return (aiocb, Errno err) I'd actually consider something more Haskellish, e.g. a variant of StateT IO where the state is the aiocb and errno, the errno initialized to eINPROGRESS and set by aioReturn and aioError (and once aioReturn is called, it can't be called again so return the cached value if needed). -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] [EMAIL PROTECTED] system administrator [openafs,heimdal,too many hats] [EMAIL PROTECTED] electrical and computer engineering, carnegie mellon universityKF8NH ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] database 101 question
On Wed, 2 Jul 2008, Galchin, Vasili wrote: Hi Don, I know where to look but I am knew to database architecture. I know there is a driver (whatever that is ... I write device drivers but this is obviously different), backend ??? My question is more generic about what pieces I would need for evenr sqlite3 for example. As far as I understand you need either Takusen, HSQL or HDBC for database access. Additionally you need some of the driver packages for the corresponding main package. Due to package dependencies it should be enough to cabal install hsql-sqlite3 or cabal install HDBC-sqlite3 With these packages you have to write your queries in SQL. If you want a nice monadic interface you may cabal install haskelldb-hdbc-sqlite3 or cabal install haskelldb-hsql-sqlite3 ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] type classes
On Wed, 2 Jul 2008, Cotton Seed wrote: Hi everyone, I'm working on a computational algebra program and I've run into a problem. In my program, I have types for instances of algebraic objects, e.g. ZModN for modular integers, and types for the objects themselves, e.g. ZModNTy for the ring of modular integers. Maybe you are also interested in: http://darcs.haskell.org/numericprelude/src/Number/ResidueClass.hs http://darcs.haskell.org/numericprelude/src/Number/ResidueClass/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
