- Glasgow-haskell-users

Timeout
by D.J.Steinitz 04 Jul '02

04 Jul '02

There seem to be a few variants of timeout around. I've copied the one from asynchronous exceptions. Is this the right one to use? There didn't seem to be a library version which I thought there should have been. I'd welcome any advice. Dominic. module ConcurrUtil(eitherIO, timeout) where import Prelude hiding (catch) import Exception import Concurrent data EitherRet a b = A a | B b | X Exception eitherIO :: IO a -> IO b -> IO (Either a b) eitherIO a b = do m <- newEmptyMVar block (do a_id <- forkIO (catch (do r <- unblock a putMVar m (A r)) (\e -> putMVar m (X e))) b_id <- forkIO (catch (do r <- unblock b putMVar m (B r)) (\e -> putMVar m (X e))) let loop = catch (takeMVar m) (\e -> do throwTo a_id e throwTo b_id e loop) r <- loop killThread a_id killThread b_id case r of A r -> return (Left r) B r -> return (Right r) X e -> throw e) timeout :: Int -> IO a -> IO (Maybe a) timeout t a = do r <- eitherIO (threadDelay t) a case r of Left _ -> return Nothing Right a -> return (Just a)

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RE: where is dynApply?
by Simon Marlow 03 Jul '02

03 Jul '02

> my documentation (sec-dynamic.html#SEC-DYNAMIC-UTIL, below) lists > functions that I cannot find. I would like to use dynApply unless you > give me a reason that I should not. (Could I implement this function > myself without knowing internals?) > > Our installation GHC Interactive, version 5.02.3 has the ":info" for > Dynamic but not for dynApply. These functions exist, but aren't exported. It looks like an oversight, I've fixed it for the forthcoming release. Cheers, Simon

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where is dynApply?
by Christian Maeder 03 Jul '02

03 Jul '02

Hello, my documentation (sec-dynamic.html#SEC-DYNAMIC-UTIL, below) lists functions that I cannot find. I would like to use dynApply unless you give me a reason that I should not. (Could I implement this function myself without knowing internals?) Our installation GHC Interactive, version 5.02.3 has the ":info" for Dynamic but not for dynApply. Thanks in advance, Christian 5.11.3. Utility functions Operations for applying a dynamic function type to a dynamically typed argument are commonly useful, and also provided: dynApply :: Dynamic -> Dynamic -> Dynamic -- unsafe. dynApplyMb :: Dynamic -> Dynamic -> Maybe Dynamic

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Can anyone get at c2hs in cvs?
by Adrian Hey 03 Jul '02

03 Jul '02

Hello, Sorry if this is slightly off topic, but I don't seem to be able to get at c2hs and I wonder if anyone here has had the same problem or knows of a fix. The instructions here.. http://www.cse.unsw.edu.au/~chak/haskell/c2hs/ say to login using.. cvs -d :pserver:anonymous@ceres.cse.unsw.edu.au:/home/chakcvs/cvs login then enter password (anonymous). When I do this all I get back is.. cvs [login aborted]: connect to ceres.cse.unsw.edu.au:2401 failed: Connection refused Thanks -- Adrian Hey

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Re: trying to compile a cgi library from hugs
by Chris Moline 02 Jul '02

02 Jul '02

On Wed, 03 Jul 2002 00:31:25 +0200, Wolfgang Thaller <wolfgang.thaller(a)gmx.net> wrote: > Your invocation of the ghc command is telling GHC to just compile > Counter.lhs to Counter.o and then create an executable (link) with just > Counter.o, not CGI.o. The linker then complains about undefined > references to the CGI module. > Solution 1: GHC works just like an ordinary UNIX-style C compiler. > Specify CGI.o on the command line. > Solution 2: use ghc --make Counter.lhs > GHC will automatically look for all required modules and compile them if > necessary (for GHC versions >= 5). ah, thanks. if anyone wants to know the cgi library works without any changes except youll have to change the .cgi's to .lhs so ghc will handle them right. sincerly, chris moline

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trying to compile a cgi library from hugs
by Chris Moline 02 Jul '02

02 Jul '02

hi. since my webhoster doesnt have haskell installed i have decided to use compiled cgi programs instead. since there doesnt seem to be a cgi library for ghc i was hoping to port the library i found at http://www.pms.informatik.uni-muenchen.de/mitarbeiter/panne/haskell_libs/CG… the library (CGI.lhs) seems to compile fine. but when i go to compile the programs i get the following [04:13pm 0.13 0.15 0.16 ~/CGI]$ mv Counter.cgi Counter.lhs Counter.cgi -> Counter.lhs [04:14pm 0.11 0.15 0.16 ~/CGI]$ ghc Counter.lhs compilation IS NOT required Counter.o: In function `__stginit_Main': Counter.o(.text+0x16): undefined reference to `__stginit_CGI' Counter.o: In function `Main_main_srt': Counter.o(.text+0x288): undefined reference to `CGI_h1_closure' Counter.o(.text+0x2a8): undefined reference to `CGI_submit_closure' Counter.o(.text+0x2ac): undefined reference to `CGI_gui_closure' Counter.o(.text+0x2b8): undefined reference to `CGI_page_closure' Counter.o(.text+0x2c0): undefined reference to `CGI_zdfShowCgiOut_closure' Counter.o(.text+0x2c4): undefined reference to `CGI_zdfMimeHTML_closure' Counter.o(.text+0x2c8): undefined reference to `CGI_wrapper_closure' Counter.o: In function `s13m_entry': Counter.o(.text+0x35e): undefined reference to `CGI_h1_closure' Counter.o: In function `s13Z_entry': Counter.o(.text+0x689): undefined reference to `CGI_submit_closure' Counter.o: In function `s144_entry': Counter.o(.text+0x6fe): undefined reference to `CGI_gui_closure' Counter.o: In function `s14f_entry': Counter.o(.text+0x7e2): undefined reference to `CGI_page_closure' Counter.o: In function `s14v_ret': Counter.o(.text+0x81a): undefined reference to `CGI_Content_con_info' Counter.o: In function `s13d_entry': Counter.o(.text+0x898): undefined reference to `CGI_zdfMimeHTML_closure' Counter.o(.text+0x89d): undefined reference to `CGI_zdfShowCgiOut_closure' Counter.o: In function `Main_main_entry': Counter.o(.text+0x91e): undefined reference to `CGI_wrapper_closure' [04:14pm 0.15 0.15 0.16 ~/CGI]$ i do not know what is happening here. any hints on how to proceed? sincerly, chris moline

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nuova chat mutitasking
by jusy 01 Jul '02

01 Jul '02

http://www.ragazze-sexy.tv Se non l'avete ancora provata vi stupirete della nuva chat multitasking e delle nuove chattiste internazionali ....................buon divertimento!!!!!!!!!!! http://www.ragazze-sexy.tv

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RE: GHC and Win32 API - help wanted
by Simon Marlow 01 Jul '02

01 Jul '02

> > | * Could anyone with cvs/fptools/makefile-expertise lend > me a hand > > | * if I try again to build only hslibs/win32 from cvs? Or is it > --------------------------------^^^^ (only) > > > a) No it is not unreasonable to expect it to build, cleanly, > > starting from scratch. It jolly well ought to. > > Ah, but (perhaps unlike Mike) I don't want to build from scratch, > but *only* the hslibs/win32 directory. You *might* be able to get away with just $ cd hslibs/win32; make HC=ghc to build with an installed GHC. But I say *might*, because (as Simon pointed out) for our own sanity, we only make sure that the libraries build with the current GHC and not every version of GHC ever released. Your chances are greatly improved if the GHC you build with is more recent. Cheers, Simon

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by vnm_2gk1fvlycqk5＠amvescap.com 30 Jun '02

30 Jun '02

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Existential Datatypes
by Jeremy Shaw 30 Jun '02

30 Jun '02

Hello, I have a question regarding named fields and existential data types. I want to extend this example from the User's guide to use named fields: data Foo = forall a. MkFoo a (a->Bool) | Nil foo = MkFoo 'g' isUpper I tried: data Foo2 = forall a. MkFoo2 { val2 :: a , func2 :: a -> Bool } But the compiler said: Can't combine named fields with locally-quantified type variables In the declaration of data constructor MkFoo2 In the data type declaration for `Foo2' Then I tried: data Foo3 = MkFoo3 { val3 :: forall a. a , func3 :: forall a. (a -> Bool) } foo3 = MkFoo3 'g' isUpper And the compiler said: Inferred type is less polymorphic than expected Quantified type variable `a' is unified with `Char' Signature type: forall a. a Type to generalise: Char When checking an expression type signature In the first argument of `MkFoo3', namely 'g' In the definition of `foo3': MkFoo3 'g' isUpper Am I doing something wrong, or can GHC just not do what I want yet? >From what I gathered looking through the mailing list, existential types are still a bit hacked up? Thanks! Jeremy Shaw.

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