January 2002 - Glasgow-haskell-users

Re: State Transformer
by Albert Lai 11 Jan '02

11 Jan '02

Theodore Norvell <theo(a)cs.ubc.ca> writes: > Jorge's question raised a question in my mind. The IOExts > module has many of the same features as the ST module, why > are there two ways to do the same thing? Is the ST module > only there for legacy purposes? My user view is that I appreciate the presence of both. When I write a pure function that can be implemented efficiently in imperative programming, I want the ST monad to support mutable variables. E.g., to implement "f n returns a list of all primes between 2 and n", I want to use a mutable array and hide it. When I write an I/O-bound routine that can be implemented conveniently with state variables, I want the IO monad to support mutable variables. Now my grief is that I cannot write a subprogram with state variables and have it reused in ST and IO. Fortunately I can write a subprogram with mutable arrays and have it reused in ST and IO, so I can write "sort a given array"; but I cannot write "increment a given integer variable". Of course, you can tell me to use mutable arrays of length 1 to simulate mutable variables. Fine!

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Re: FFI
by Ronald Legere 11 Jan '02

11 Jan '02

Mark, I have tried several of the available methods. Greencard works pretty well for most things, but these days I use straight ffi (with CForeign libs that come with ghc) and code it myself. It turned out to be a lot less difficult then I imagined to marshall simple structures and arrays back and forth. CHeers! > From: Mark Conway Wirt <mark(a)ArsConcero.org> > To: glasgow-haskell-users(a)haskell.org > Subject: FFI > __________________________________________________ Do You Yahoo!? Send FREE video emails in Yahoo! Mail! http://promo.yahoo.com/videomail/

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ghc-5.03 release candidate installer available (win32)
by Sigbjorn Finne 10 Jan '02

10 Jan '02

In preparation for a ghc-5.03 snapshot release, a test installer for Win32 platforms is now available: http://www.galois.com/~sof/ghc-503.msi (*) Size: 25.1 Mb. Please let me know if you run into any problems with it. thanks, --sigbjorn btw, Mike Thomas deserves a special mention for very helpful (and quick) feedback on the ghc-5.02.2 RC installer. Feedback that has been used to improve both the 5.02.2 and 5.03 installer setups. * - This installer relies on the Windows Installer runtime to operate. If, after having downloaded the above file, double-clicking on the MSI file doesn't start up the installer, the likely cause is that you don't have the runtime installed on your machine. Redistributables of the runtime can be downloaded from Microsoft: * http://www.microsoft.com/downloads/release.asp?releaseid=32831 (Windows 95,98 and ME version) * http://www.microsoft.com/downloads/release.asp?releaseid=32832 (Windows NT and 2000 version). Try installing the appropriate version before double-clicking again on the GHC installer.

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ghc-5.02.2 release candidate installer available (win32)
by Sigbjorn Finne 09 Jan '02

09 Jan '02

In preparation for the upcoming release of 5.02.2, I've made available a test installer for Win32 platforms, in the hope that any packaging glitches can be caught before it's too late. The installer is available via http://www.galois.com/~sof/ghc-502-2.msi (*) It's big: 21.7 Mb. Please let me know if you run into any problems with it (or not). thanks, --sigbjorn * - This installer relies on the Windows Installer runtime to operate. If, after having downloaded the above file, double-clicking on the MSI file doesn't start up the installer, the likely cause is that you don't have the runtime installed on your machine. Redistributables of the runtime can be downloaded from Microsoft: * http://www.microsoft.com/downloads/release.asp?releaseid=32831 (Windows 95,98 and ME version) * http://www.microsoft.com/downloads/release.asp?releaseid=32832 (Windows NT and 2000 version). Try installing the appropriate version before double-clicking again on the GHC installer.

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Re: GHC Poll: scope in GHCi
by cwitty＠newtonlabs.com 09 Jan '02

09 Jan '02

"Simon Marlow" <simonmar(a)microsoft.com> writes: > Ok, so in general a 'scope' can be constructed by combining: > > 1. the full top-level scope from zero or more *interpreted* modules > 2. the exports of zero or more modules (interpreted or compiled) > 3. any temporary bindings made on the command line I'd like to suggest one more thing that it would be nice to have in scope. I would like every loaded module to be imported "qualified" into the scope. (In fact, I would prefer if this were the default, although I suppose it might be useful to have a way to turn it off.) Carl Witty

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Happy documentation
by George Russell 09 Jan '02

09 Jan '02

Any chance of getting the Happy documentation as HTML in a .tar.gz file? Or do I have to get DocBook running on x86 Linux machine (I normally use Sparc/Solaris) to compile it from source, or do a recursive wget on http://www.haskell.org/happy/doc/html/happy.html?

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GHC Poll: scope in GHCi
by Simon Marlow 09 Jan '02

09 Jan '02

Folks, There's a long-standing problem in GHCi, namely that when you select a compiled module with ':m M' you can only see the exports of M, and even the exports of the Prelude are hidden. Several people have suggested that this should be improved, and I'm just getting around to implementing something more useful. This message is to gather suggestions on what the user interface should look like in a more general setting, from people who use GHCi more than we do :-) Ok, so in general a 'scope' can be constructed by combining: 1. the full top-level scope from zero or more *interpreted* modules 2. the exports of zero or more modules (interpreted or compiled) 3. any temporary bindings made on the command line I'm assuming name clashes are handled in the normal Haskell 98 way, ie. lazilly, so it might actually make sense to combine the top-level scope of more than one module. Whatever user interface we adopt should provide a way to manipulate these sets. Here's one suggestion: :m M1..Mn set sets 1 & 2 from M1..Mn - use list 1 if Mi is interpreted, otherwise list 2. :m +M adds M to set 1 or 2. :m -M removes M from set 1 or 2. Which leaves one remaining case: adding an interpreted module to set 2. Perhaps this could be ':m *M'. Does anyone have any better suggestions? Cheers, Simon

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RE: GHC Poll: scope in GHCi
by Simon Marlow 09 Jan '02

09 Jan '02

> Is there any haskell interpreter done it already? > Hugs and hmake support ":also" command. I don't know > now exactly it works, but quick test showed than > it (sometimes) helps to mix scopes: > > Hi (hmake/nhc98): > ------- begin cut > Prelude> :also Maybe > [Std module... /usr/local/opt/nhc98/include/nhc98/Prelude.hi] > [Std module... /usr/local/opt/nhc98/include/nhc98/Maybe.hi] > Maybe> print "a" > "a" > Maybe> :also IO > [Std module... /usr/local/opt/nhc98/include/nhc98/Prelude.hi] > [Std module... /usr/local/opt/nhc98/include/nhc98/Maybe.hi] > [Std module... /usr/local/opt/nhc98/include/nhc98/IO.hi] > IO> listToMaybe [1] > Just 1 > ------- end cut Hugs's :also is the same as GHC's :add; it causes another module to be loaded without throwing away the existing loaded set, and it changes the scope to the new module. Hi seems to be doing something slightly different, but I can't find any documentation on Hi's :also command. Cheers, Simon

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FORTRAN and HASKELL
by clusterpoli 09 Jan '02

09 Jan '02

Somebody works with together FORTRAN and Haskell. Exists some funcao to transform codigo FORTRAN into codigo HASKELL? Thanks, Allan Bruno __________________________________________________________________________ AcessoBOL, só R$ 9,90! O menor preço do mercado! Assine já! http://www.bol.com.br/acessobol

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RE: Clean 2.0 dynamics
by Simon Peyton-Jones 09 Jan '02

09 Jan '02

I think that "proper" dynamics are one of those things that are easier said than done. Yes, GHC has more of the infrastructure now than it used to have. But I don't think it's a routine matter to come up with a robust design, or to implement that design. But it would certainly be a good and useful project. We don't have any plans here to work on it, though. Simon | -----Original Message----- | From: Krasimir Angelov [mailto:ka2_mail@yahoo.com] | Sent: 09 January 2002 09:00 | To: glasgow-haskell-users(a)haskell.org | Subject: Clean 2.0 dynamics | | | Hi | | Are you known about new Clean 2.0 compiler and your | new features. There is two general extensions in | language: Dinamics and their automatic loading\writing | to files or streams. Clean Dinamics are most similar | to corresponding Haskell Dinamic type. Main difference | is in some language extensions which allow dynamic | types to be dynamicaly unified. See following Clean | function: | | dynApply :: Dynamic Dynamic -> Dynamic | dynApply (f :: a -> b) (x :: a) = dynamic (f x :: b) | dynApply df dx = dynamic ("cannot apply",df,"to",dx) | | In Haskell the only way to define dynApply is with | using of unsafeCoerce# which is type unsafe. Runtime | type unification is useful but not obligatory. I think | that most important thing is automatic loading\writing | of Dynamics. Loading/writing facilities in Clean needs | dynamic linker which can dynamical loading of object | files. As I known in GHC-5.02 we already have such | linker which is part of runtime system. I think that | is'n too difficult to implement this feature in GHC. | Is there any plan to implement this. For functional | programing Dynamics can be same as COM/Corba for OO | programing. While runtime type unification needs some | syntax extensions (As I known using polymorphic types | in pattern type signatures are always implemented | according to rank-N types), dynamic linking needs only | backend changes. | | Krasimir | | __________________________________________________ | Do You Yahoo!? | Send FREE video emails in Yahoo! Mail! | http://promo.yahoo.com/videomail/ | | | _______________________________________________ | Glasgow-haskell-users mailing list | Glasgow-haskell-users(a)haskell.org | http://www.haskell.org/mailman/listinfo/glasgow-| haskell-users |

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