Re: [Haskell-cafe] GHCi Loop Detection
Thanks. On Sat, Jun 2, 2012 at 12:57 PM, Michal Terepeta michal.terep...@gmail.comwrote: On 01.06 11:06, John Van Enk wrote: Hi Cafe, Is there a reason that the GHCi interpreter doesn't detect and report infinite loops in statements like this (like compiled programs do) even though no CPU time appears to be used? My (admittedly weak) searching for an answer didn't turn much up. let s | not $ null s = [] in s GHCi v7.0.4 on OSX Thanks, John Hi John, I think this is a known problem in GHCi: http://hackage.haskell.org/trac/ghc/ticket/2786 Regards, Michal ___ 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] GHCi Loop Detection
Hi Cafe, Is there a reason that the GHCi interpreter doesn't detect and report infinite loops in statements like this (like compiled programs do) even though no CPU time appears to be used? My (admittedly weak) searching for an answer didn't turn much up. let s | not $ null s = [] in s GHCi v7.0.4 on OSX Thanks, John ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ANNOUNCE: hspec-0.1.0 (Behavior Driven Development for Haskell)
I second the request to publish this to hackage. On Tue, Feb 15, 2011 at 1:02 PM, Simon Michael si...@joyful.com wrote: On 2/11/11 8:42 PM, trysta...@comcast.net wrote: Any advice, comments, or questions are welcome. Hi Trystan.. it looks great. I like the rubyish brevity and readability. Please do publish on hackage. What should we read to find out more about this style of tests, http://rspec.info ? When you get a chance, some examples using quickcheck properties would be interesting. I suppose it could also be made to accept hunit tests ? I currently use test-framework partly for it's nice concurrent test runner. I assume hspec tests currently run in sequence ? Any thoughts on how this fits in with the existing haskell test tools, when to use it ? Thanks for working on it. -Simon ___ 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] Re: [Haskelldb-users] ANNOUNCE: HaskellDB 2.0: Scrap your SQL strings
Hooray for collaboration! I think this emphasizes the need for some sort of social aspect on Hackage... On Mon, Oct 11, 2010 at 10:58 AM, Justin Bailey jgbai...@gmail.com wrote: On Mon, Oct 11, 2010 at 7:56 AM, Christopher Done chrisd...@googlemail.com wrote: Hey that's cool, I hadn't seen that. This'll reduce my code significantly, especially mkFieldWithName. Cheers! I'm not sure if it supports the parameterization of records that you detailed in your post - let me know how it works for you. Patches always welcome as well :) Justin ___ 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] ANNOUNCE: Utrecht Haskell Compiler (UHC), version 1.1.0
Can UHC self-host yet? How does the runtime compare to GHC's? I suppose I could just go look... :) On Wed, Sep 22, 2010 at 10:30 AM, Atze Dijkstra a...@cs.uu.nl wrote: Utrecht Haskell Compiler -- second release 1.1.0 The UHC team is happy to announce the second public release of the Utrecht Haskell Compiler (UHC). UHC supports almost allmost all Haskell98 and Haskell2010 features plus some experimental extensions. The compiler runs on MacOSX, Windows (cygwin), and various Unix flavors. This second release has the following highlights relative to the previous first release: * Supports most of the Haskell2010 features. * Generic deriving [1]. * UHC knows about packages, and Cabal version 1.9.3 and later have basic support for UHC, so that Cabal can be used to build UHC packages. * For the default backend libraries are provided until including package haskell98. * The runtime system is no longer dependent on Boehm garbage collector, but uses UHCs own, a swap space collector allowing parameterization with backend specifics. * More programs from the nofib test suite compile and run. * Many smaller and larger problems fixed. For more info see http://www.cs.uu.nl/wiki/UHC Getting started Download -- UHC is available for download as source distribution via the UHC home page: http://www.cs.uu.nl/wiki/UHC Here you will also find instructions to get started and the specifics of what UHC can and cannot do. Status of the implementation Over the past year much effort by many people has been put into improving UHC, in particular to make it compile and run more library modules and test programs. Although the UHC project is very much work in progress overall reliability has improved, bugs have been fixed, and some Hackage packages compile. Warning --- Although we think that the compiler is stable enough to compile substantial Haskell programs, we do not recommend yet to use it for any serious development work in Haskell. We ourselves use the GHC as a development platform! We think however that it provides a great platform for experimenting with language implementations, language extensions, etc. Mailing lists - For UHC users and developers respectively: http://mail.cs.uu.nl/mailman/listinfo/uhc-users http://mail.cs.uu.nl/mailman/listinfo/uhc-developers Bug reporting - Please report bugs at: http://code.google.com/p/uhc/issues/list The UHC Team [1] Jose Pedro Magalhaes, Atze Dijkstra, Johan Jeuring, and Andres Loeh. A generic deriving mechanism for Haskell. http://dreixel.net/research/pdf/gdmh_draft.pdf (see Section 7.1 for the discussion on constrained datatypes) - Atze - Atze Dijkstra, Department of Information and Computing Sciences. /|\ Utrecht University, PO Box 80089, 3508 TB Utrecht, Netherlands. / | \ Tel.: +31-30-2534118/1454 | WWW : http://www.cs.uu.nl/~atze . /--| \ Fax : +31-30-2513971 | Email: a...@cs.uu.nl / |___\ ___ 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] Changing my Profile
On the bottom of this page, enter your e-mail address: http://www.haskell.org/mailman/listinfo/haskell-cafe http://www.haskell.org/mailman/listinfo/haskell-cafeThis is also provided in the footer of these list e-mails. On Mon, Aug 23, 2010 at 1:35 PM, David Webster dwwebste...@gmail.comwrote: Is there any way to change my profile or signup options so that I don't get CC'ed on every posting to Haskell-Cafe? David ___ 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] lambdacats
I happened to download them all (i think all) a while ago to torment my coworkers: http://sw17ch.com/dump/lambdacats.zip Enjoy. On Fri, Aug 6, 2010 at 12:12 AM, Tony Morris tonymor...@gmail.com wrote: Hello, does anyone happen to have the lambdacats page cached? The domain ( arcanux.org) and server have disappeared and the wayback machine doesn't have the images. -- Tony Morris http://tmorris.net/ ___ 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] real-time audio processing [Was: can Haskell do everyting as we want?]
It's not an EDSL (though I'm a huge fan of the concept) because we wan't to pitch the language to programmers who currently use C/Ada. As much as I love EDSL's, they are particularly hard to sell to entrenched engineers without substantial effort or mandate. Dangling a few neat features on top of a comfortable tool set hopefully will stimulate some curiosity and help sell Haskell/EDSL's in the future... On Fri, Aug 6, 2010 at 11:34 AM, C K Kashyap ckkash...@gmail.com wrote: Hey John, The language you are working on - is it a EDSL in Haskell? If not, had you considered such an option? On Thu, Aug 5, 2010 at 8:11 PM, Job Vranish job.vran...@gmail.com wrote: Yeah Atom is pretty slick, though unfortunately it's not quite powerful enough for much of the stuff that we do. John Van Enk and I are actually working on a language that's similar to C (and compiles to C), but has polymorphism, type inference and other goodies. The goal is to make working on embedded systems a bit less painful, while still being able to do anything that C can do (like run on an 8 bit micro). Hopfully, if things go as planned, we'll have a working beta out by the end of the month :) - Job On Wed, Aug 4, 2010 at 5:58 PM, Don Stewart d...@galois.com wrote: job.vranish: + 1 This is probably the biggest obstacle to using Haskell where I work. (Aviation industry, software for flight management systems for airplanes) We often need to perform some computations with hard deadlines, say every 20ms, with very little jitter. Major GC's spoil the fun; It's quite easy to have a major GC take longer than 20ms, and currently they are not pauseable (nor is it trivial to make them so). It would be very nice to have some annotation/DSL/compiler-flag that would let me run a small block of mostly regular haskell code under hard, real-time constraints. Hmm, it looks like the HASP project is working on some of this, though I'm not sure how portable their work is back to GHC: http://hasp.cs.pdx.edu/ Or look at EDSLs, like Atom: http://hackage.haskell.org/package/atom ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Regards, Kashyap ___ 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] finding out which gcc is hard-coded into a ghc?
If you're on Windows, I believe you can find the gcc.exe at the following location: C:\Program Files\Haskell Platform\2009.2.0.2\gcc.exe See this link for how to pick which C compiler to use: http://www.haskell.org/ghc/docs/6.12.2/html/users_guide/options-phases.html#replacing-phases 2010/8/6 Günther Schmidt gue.schm...@web.de Hello, how can I find out which gcc a ghc is hard-coded to use and is it possible to override it? Günther ___ 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] lambdacats
I apologize if I missed any. :( On Fri, Aug 6, 2010 at 3:03 PM, Henning Thielemann schlepp...@henning-thielemann.de wrote: Sean Leather schrieb: On Fri, Aug 6, 2010 at 12:12 AM, Tony Morris wrote: Hello, does anyone happen to have the lambdacats page cached? The domain (arcanux.org http://arcanux.org) and server have disappeared and the wayback machine doesn't have the images. On Fri, Aug 6, 2010 at 18:43, John Van Enk wrote: I happened to download them all (i think all) a while ago to torment my coworkers: http://sw17ch.com/dump/lambdacats.zip And from that to this: http://spl.smugmug.com/Humor/Lambdacats/13227630_eKt46 I remember the first lambdacat said something like why can't u curry this funkshun. I don't see it in this list. :-( ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ANNOUNCE: DSTM 0.1.1
Is there a Git/Darcs dev repo hiding anywhere we could submit patches to? On Tue, Aug 3, 2010 at 4:35 AM, Frank Kupke f...@informatik.uni-kiel.dewrote: Hi, DSTM is an implementation of a robust distributed Software Transactional Memory (STM) library for Haskell. Many real-life applications are distributed by nature. Concurrent applications may profit from robustness added by re-implementation as distributed applications. DSTM extends the STM abstraction to distributed systems and presents an implementation efficient enough to be used in soft real-time applications. Further, the implemented library is robust in itself, offering the application developer a high abstraction level to realize robustness, hence, significantly simplifying this, in general, complex task. The DSTM package consists of the DSTM library, a name server application, and three sample distributed programs using the library. Provided are a simple Dining Philosophers, a Chat, and a soft real-time Bomberman game application. Distributed communication is transparent to the application programmer. The application designer uses a very simple name server mechanism to set up the system. The DSTM library includes the management of unavailable process nodes and provides the application with abstract error information thus facilitating the implementation of robust distributed application programs. For usage please look into the documentation file: DSTMManual.pdf. The package including the documentation can be found on:http://hackage.haskell.org/package/DSTM-0.1.1 Best regards, Frank Kupke ___ 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] Re: Mining Twitter data in Haskell and Clojure
Would it be possible to use an IntMap instead of your OrdMap? Perhaps zip your users with [0..] and key off the integer? As a side note, I threw this package onto Hackage a while ago and may suit your needs if you decide to move to something like IntMap: http://hackage.haskell.org/package/EnumMap It does have a performance hit over an IntMap, but I'm not entirely sure how large it is. /jve On Mon, Jun 14, 2010 at 10:27 AM, braver delivera...@gmail.com wrote: I've supplied a profile report there. Since I load the graphs in memory and then walk them a lot, the time seems expected. It allocates a lot, though. The main graph type is type Graph = M.Map User AdjList type AdjList = M.Map Day Reps type User = B.ByteString type Day = Int type Reps = M.Map User Int and I walk it with M.foldWithKey. Folks said it's not strict enough, hence I tried to seq the step function, but to no avail so far. ___ 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] Re: Haskell.org re-design
Hot. On Wed, Apr 7, 2010 at 2:35 PM, Thomas Schilling nomin...@googlemail.comwrote: http://i.imgur.com/kFqP3.png Didn't know about CSS's rgba to describe transparency. Very useful. On 7 April 2010 18:19, Gregory Crosswhite gcr...@phys.washington.edu wrote: Ooo, I really like this revision; it is a major improvement in your design! I particularly like the picture you chose for the top, and the new way that you have laid out all of the boxes and made the bottom right box a different shade so that it is easier to distinguish it as a different column. Also, I concur with your use of the inverted pyramid model, even if it comes at the expense of a little redundancy. My only quibble is that I don't like the fact that the summary text at the top has a font background color, so that there are in essence several boxes around the text of different sizes and with space in between the lines. I recognize that the purpose of the font background was to help the text contrast with the picture behind it, but it would be nicer if there were a better solution, such as by putting a box around all of the text and then filling that with color (so there aren't boxes of different sizes containing the text and empty spaces between the lines), or by putting a translucent box around the text so that we can still see the background but it's faded a bit so that the text still shows up. Cheers, Greg On Apr 7, 2010, at 9:53 AM, Thomas Schilling wrote: Yup, I have to agree. The Ruby web site certainly is the best web site for a programming language that I've come across, but it's certainly not amazing. I like the python documentation design, but their home page is a bit dull. Anyway, here's another variation, this time with more colour: http://i.imgur.com/Lj3xM.png The image is about 80k (while the website alone is 10k) so I hope there won't be any bandwidth issues. Regarding the particular contents: (a) I won't post another version for every tiny wibble. You know, you can actually post text via email (yes, really!) so if anyone has improvements for how the sections should look like, post the suggested alternative contents on this list. (b) A little redundancy is no problem at all. I try to follow the inverted pyramid model: put all the important information at the top, and add more details below. If that leads to a small amount of duplication so be it. (c) As mentioned before, we don't want a perfect home page, we simply want a better one. Incremental improvements can be made later on. (d) Who actually *can* update the homepage? Ian, Ross, Malcolm, Simon M? (e) I don't have an iPhone, *Droid, or iPad, so I'd need some help testing on any of those. (f) The design is not fixed width, and most sizes are specified in terms of font size or percentages. I merely added a max-width restriction so that it still looks decent on maximised screens. I tried to remove it, but that just doesn't look good anymore. On 7 April 2010 14:19, Daniel Fischer daniel.is.fisc...@web.de wrote: Am Mittwoch 07 April 2010 04:09:17 schrieb Gregory Crosswhite: While I think that (d) is a valid concern, it is also important not to let the perfect be the enemy of the good. If we agree that the proposed web site layout is sufficiently better than the current one and is good enough aesthetically, then I think we should go ahead and switch to the new layout and *then* start thinking about how we could make it Good plan. *completely amazing* like the Ruby web site, www.ruby-lang.org ? Sure, that looks pretty good, but completely amazing? because if we demand completely amazing for our *first* try then I fear that all that will happen is that nothing will change because the bar will have been set too high. Cheers, Greg ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Push the envelope. Watch it bend. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Push the envelope. Watch it bend. ___ 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] Why does Haskell not infer most general type?
I don't believe that the monomorphism restriction has anything to do with this. Removing it does not generalize the type. On Tue, Apr 6, 2010 at 4:46 PM, Brandon S. Allbery KF8NH allb...@ece.cmu.edu wrote: On Apr 6, 2010, at 15:56 , Job Vranish wrote: Is haskell supposed to always infer the most general type (barring extensions)? Look up the monomorphism restriction. -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu 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 mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Are there any female Haskellers?
http://en.wikipedia.org/wiki/Grace_Hopper http://en.wikipedia.org/wiki/Grace_HopperA heck of a lady. On Sat, Mar 27, 2010 at 12:51 PM, Andrew Coppin andrewcop...@btinternet.com wrote: Ozgur Akgun wrote: Nevertheless, I guess you're right. There are very few females in most of the CS topics, and haskell is no different. This is my experience too. Although note that apparently the world's very first computer programmer was apparently a woman... ___ 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] ANN: powerpc-0.0.1
Serguey, I'm working on a similar project. What's the chance you have your source code in the open? /jve On Thu, Mar 11, 2010 at 7:30 AM, Serguey Zefirov sergu...@gmail.com wrote: 2010/3/10 Tom Hawkins tomahawk...@gmail.com: On Wed, Mar 10, 2010 at 8:07 AM, Warren Henning warren.henn...@gmail.com wrote: Wow. Quite ambitious. Was this inspired by work at your current employer like with Atom and some of the other stuff you've released? Yes, we had an immediate need to debug some machine code. I looked around, but all the emulators I found (PSIM, et al.) were too complicated. I'm also intrigued by the emphasis on software verification at the object code level for aerospace (DO-178). I figure better tools in this area may open the door to using advanced design methods like Atom for avionics. Of course it's unlikely this project will reach that level of maturity, but you never know. We wrote the debugger and simulator for AVR line of microcontroller cores. We used a DSEL to describe inner workings of commands and now try to apply it to ARM ISA. The Haskell code is heavy on the use of type-level computations and, especially, assiciated types. ___ 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] ANN: powerpc-0.0.1
Serguey, The system I'm writing has a type in place for the AVR instruction set. I'm working on writing an assembler/disassembler for it as well. It might make sense, if your employer deems it worthwhile to release the code, to collaborate. /jve On Thu, Mar 11, 2010 at 11:35 AM, Serguey Zefirov sergu...@gmail.comwrote: 2010/3/11 John Van Enk vane...@gmail.com: Serguey, I'm working on a similar project. What's the chance you have your source code in the open? /jve I'll ask. But chances are pretty small. I'll think about reimplementing command description from scratch. On Thu, Mar 11, 2010 at 7:30 AM, Serguey Zefirov sergu...@gmail.com wrote: 2010/3/10 Tom Hawkins tomahawk...@gmail.com: On Wed, Mar 10, 2010 at 8:07 AM, Warren Henning warren.henn...@gmail.com wrote: Wow. Quite ambitious. Was this inspired by work at your current employer like with Atom and some of the other stuff you've released? Yes, we had an immediate need to debug some machine code. I looked around, but all the emulators I found (PSIM, et al.) were too complicated. I'm also intrigued by the emphasis on software verification at the object code level for aerospace (DO-178). I figure better tools in this area may open the door to using advanced design methods like Atom for avionics. Of course it's unlikely this project will reach that level of maturity, but you never know. We wrote the debugger and simulator for AVR line of microcontroller cores. We used a DSEL to describe inner workings of commands and now try to apply it to ARM ISA. The Haskell code is heavy on the use of type-level computations and, especially, assiciated types. ___ 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] How to break strings and put to a tuple
These are beginning to look like homework questions... On Thu, Mar 4, 2010 at 11:38 AM, Pradeep Wickramanayake prad...@talk.lkwrote: Hi, sortList2 :: String - String sortList2 (x:xs) | x == ',' = | otherwise = [x] ++ sortList2 xs im breaking a one specific string and putting them to each word. But I need to put them to a tuple. Can someone help me with the code Please. __ Information from ESET NOD32 Antivirus, version of virus signature database 4915 (20100304) __ The message was checked by ESET NOD32 Antivirus. http://www.eset.com ___ 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] Evolving Faster Haskell Programs (now with LLVM!)
What's the chance you have generational graphs for the rest of your examples like you do with the first? I'd be interested to see those. On Mon, Mar 1, 2010 at 3:02 AM, Don Stewart d...@galois.com wrote: http://donsbot.wordpress.com/2010/03/01/evolving-faster-haskell-programs-now-with-llvm/ … In which I use genetic algorithms to search for optimal LLVM optimizer passes to make Haskell programs faster … LLVM + GHC is a lot of fun. -- Don ___ 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] Real-time garbage collection for Haskell
The whole concept of lazy evaluation seems to run counter to the idea of real-time systems. Hi Thomas, Lazy evaluation is okay since it has deterministic characteristics. We can predict what will happen quite accurately (heck, we can model it in simpler cases). It might take a while to get people comfortable with the concept, but it wouldn't be a show stopper (actually, some people would benefit greatly from lazy evaluation and referential transparency). The GC throws a wrench in a system which would otherwise make it past certification with enough effort. If we can write a GC that can be modeled, we'd have an excellent case for using Haskell in aerospace. /jve On Mon, Mar 1, 2010 at 2:37 PM, Thomas Schilling nomin...@googlemail.comwrote: On 1 March 2010 16:27, Job Vranish job.vran...@gmail.com wrote: My current area of work is on realtime embedded software programming for avionics systems. We do most of our coding in Ada but I've been dreaming of using haskell instaed. Do you really think this is realistic? Garbage collector aside, Haskell's execution model is very difficult to predict, which I would suspect is crucial for even soft real-time systems. The whole concept of lazy evaluation seems to run counter to the idea of real-time systems. Lazy evaluation essentially says do as little as possible *now* at the expense of having to do it all later. For a real-time system you want almost the opposite; you want to make sure that you complete all the required work in the current time slice. A possible workaround would be to sprinkle lots of 'rnf's around your code to make sure you don't build up a thunk or two that will delay you later. And if you do this, aren't you essentially programming in a strict functional language (like SML or O'Caml)? By careful profiling you and auditing you can probably rule out most of the potential bad cases, so it can be acceptable for a soft real-time system (Galois did something like this, I believe). But for avionics systems you probably want to more assurances than that, don't you? -- Push the envelope. Watch it bend. ___ 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] Real-time garbage collection for Haskell
Simon, Would a more predictable GC or a faster GC be better in your case? (Of course, both would be nice.) /jve On Mon, Mar 1, 2010 at 9:33 PM, Simon Cranshaw simon.crans...@gmail.comwrote: On Sun, Feb 28, 2010 at 6:06 PM, Pavel Perikov peri...@gmail.com wrote: Did you really seen 100ms pauses?! I never did extensive research on this but my numbers are rather in microseconds range (below 1ms). What causes such a long garbage collection? Lots of allocated and long-living objects? I am using an automated options trading system written in Haskell. I'm more on the business side than the technical side of the issues so I'm not clear on all the details. I can confirm that without tweaking the RTS settings we were seeing over 100ms GC pauses. I've mainly been trying to minimise our overall response time and we were able to improve this by increasing the allocation area with -A. I think this brought GC well under 100ms. We are still working on analysis of this. I can also confirm, as others seem to have found, that under 6.12 the parallel GC seemed to make things much worse. I am always turning it off with -qg. If there is a project to improve performance of the GC I could be interested to contribute. Simon Cranshaw ___ 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] ANN: atom-1.0.0
Hmm... that's my outdated blog post. I've been meaning to add an updated version. I'll try and get to that soon. On Sat, Feb 13, 2010 at 7:30 PM, Yves Parès limestr...@gmail.com wrote: I've been interested in using Atom since I saw this: http://blog.sw17ch.com/wordpress/?p=84 However those samples are very outdated, do you have newer ones? Tom Hawkins-2 wrote: Atom is a Haskell DSL for designing hard realtime embedded software. The 1.0 release is meant to indicate some level of stability; most of the core has been unchanged for quite some time. That said, there are a few interesting changes in 1.0. First the var' family of variable declarations (bool', word8', double', etc.) are no longer part of the Atom monad. For example: bool' :: Name - V Bool This cleaned up quite a bit of code in our production design. This also made the randomization in Atom's unit testing framework monadless as well. The other significant change with 1.0 is all state variables are now packed into a hierarchical C structure that matches the hierarchy of the Atom design. Not only does this make the generated C a bit more legible, it is now possible to interface external C code directly to Atom's state variables and arrays. Prior to this change, all interfacing had to be done through var' declarations and action calls -- too often a messy process. To further aid interfacing to external code, Atom now generates a header file that exposes both the iterative function and the hierarchical state structure. -Tom http://hackage.haskell.org/package/atom ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe - Yves Parès Live long and prosper -- View this message in context: http://old.nabble.com/ANN%3A-atom-1.0.0-tp27574165p27579930.html Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com. ___ 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] Re: How many Haskell Engineer I/II/IIIs are there?
I _think_ that the abstract points out that reference-counted garbage collection can be done deterministically. Haskell could some day be an excellent replacement for C/Ada in safety critical markets, but some serious changes to the RTS (most having to do with memory allocation, garbage collection, and multi-threading) would have to be made. If the GC becomes deterministic, then a much better case can be made for using the language on a plane or in medical devices. /jve On Fri, Feb 12, 2010 at 10:29 AM, Simon Marlow marlo...@gmail.com wrote: On 11/02/2010 17:01, John Van Enk wrote: Here's the paper: http://comjnl.oxfordjournals.org/cgi/content/abstract/33/5/466 Can you say a bit about why that GC fits your needs? Must it be that particular algorithm? I don't seem to be able to find the paper online. Replacing GHC's RTS is no mean feat, as you're probably aware. There are a large number of dependencies between the compiler, the RTS, and the low-level libraries. I expect rather than thinking about replacing the RTS it would be more profitable to look at what kinds of things you need the RTS to do that it currently does not. I'm aware that some people need a GC with shorter pause times. We'll probably put that on the roadmap at some point. Cheers, Simon ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: How many Haskell Engineer I/II/IIIs are there?
I need to be able to swap out the RTS. The place I want to stick Haskell absolutely needs its own custom RTS, and currently, I don't think it's all that easy or clean to do that. Am I wrong? Are there resources describing how to do this already? /jve On Thu, Feb 11, 2010 at 10:12 AM, Michael Lesniak mlesn...@uni-kassel.dewrote: Hello, elegance of Haskell. Whether Haskell becomes an easy choice for commercial work or remains a boutique language depends on how easy it is to build today's applications. Do you (or anyone reading this thread) know of some kind of wishlist of missing features and/or libraries? Would be nice to see what's still missing. - Michael ___ 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] Re: How many Haskell Engineer I/II/IIIs are there?
I'm not specifically interested in raw hardware, but I am interested in, say, making the garbage collection deterministic and altering the scheduler to fit some other needs. I'll try and find a link to the paper describing the GC i want to implement On Thu, Feb 11, 2010 at 11:10 AM, Ivan Panachev ivan.panac...@gmail.comwrote: On Thu, Feb 11, 2010 at 6:30 PM, John Van Enk vane...@gmail.com wrote: I need to be able to swap out the RTS. The place I want to stick Haskell absolutely needs its own custom RTS, and currently, I don't think it's all that easy or clean to do that. Am I wrong? Are there resources describing how to do this already? Could you be a bit more precise about your RTS needs? For example, if you want to run Haskell on raw hardware you might be interested with House project, http://programatica.cs.pdx.edu/House/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: How many Haskell Engineer I/II/IIIs are there?
Here's the paper: http://comjnl.oxfordjournals.org/cgi/content/abstract/33/5/466 On Thu, Feb 11, 2010 at 11:45 AM, John Van Enk vane...@gmail.com wrote: I'm not specifically interested in raw hardware, but I am interested in, say, making the garbage collection deterministic and altering the scheduler to fit some other needs. I'll try and find a link to the paper describing the GC i want to implement On Thu, Feb 11, 2010 at 11:10 AM, Ivan Panachev ivan.panac...@gmail.comwrote: On Thu, Feb 11, 2010 at 6:30 PM, John Van Enk vane...@gmail.com wrote: I need to be able to swap out the RTS. The place I want to stick Haskell absolutely needs its own custom RTS, and currently, I don't think it's all that easy or clean to do that. Am I wrong? Are there resources describing how to do this already? Could you be a bit more precise about your RTS needs? For example, if you want to run Haskell on raw hardware you might be interested with House project, http://programatica.cs.pdx.edu/House/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: How many Haskell Engineer I/II/IIIs are there?
Well, my point here is that if we want to see GHC branch into other fields (mine being safety critical), and actually see the code generated by GHC be what's really running (rather than once-removed in the form of an EDSL), some changes will have to be made. Being able to experiment with GHC's RTS and possibly being able to write your own (should the project require it) would go a long way to helping me make the case for GHC in safety critical. Perhaps I'd be better off looking at UHC/LHC/JHC as a starting place. /jve On Thu, Feb 11, 2010 at 12:13 PM, Jason Dusek jason.du...@gmail.com wrote: Is JHC not suitable in this case? It won't compile all of Haskell but it does some to be doing the right things as regards a pluggable RTS. I think it's fair to say at this point that GHC can compile all the Haskell we want and that new Haskell pieces will come to GHC before anything else gets them. So going with a totally new system, front-to-back, is not really desirable when all you want is a new RTS; however, I don't think GHC was designed to be a Haskell compiler superserver. -- Jason Dusek ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: How many Haskell Engineer I/II/IIIs are there?
I'd suggested this in an earlier SoC thread. 2010/2/11 Matthias Görgens matthias.goerg...@googlemail.com Implementing an alternative RTS for GHC seems like a viable Google Summer of Code project to me. What do you think? ___ 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] Re: How many Haskell Engineer I/II/IIIs are there?
I'll definitely take a closer look. On Thu, Feb 11, 2010 at 1:09 PM, John Meacham j...@repetae.net wrote: On Thu, Feb 11, 2010 at 06:57:48PM +0100, Henning Thielemann wrote: John Van Enk schrieb: I need to be able to swap out the RTS. The place I want to stick Haskell absolutely needs its own custom RTS, and currently, I don't think it's all that easy or clean to do that. Am I wrong? Are there resources describing how to do this already? As far as I know JHC is intended to work without an RTS. It is more that the RTS is generated as a part of the normal code generation process, this is done by implementing as much as possible in haskell itself, jhc has a very rich set of unboxed primitives, making it as expressible as c-- for the most part, for the bits of C I do need, I try to make them conditionally compilable, so parts that arn't used will not be included. all in all, the overhead is ~= 1k or so. A side effect is that jhc is very lightly coupled to any particular RTS, so experimenting with alternate ones is pretty straigtforward. John -- John Meacham - ⑆repetae.net⑆john⑈ - http://notanumber.net/ ___ 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] Re: How many Haskell Engineer I/II/IIIs are there?
Perhaps just defining the interface and demonstrating that different RTS's are swappable would be enough? 2010/2/11 Alp Mestanogullari a...@mestan.fr It seems quite big for a 3 months project made by a student, though. 2010/2/11 Matthias Görgens matthias.goerg...@googlemail.com Implementing an alternative RTS for GHC seems like a viable Google Summer of Code project to me. What do you think? -- Alp Mestanogullari http://alpmestan.wordpress.com/ http://alp.developpez.com/ ___ 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] How many Haskell Engineer I/II/IIIs are there?
Not using it yet, but there's been a large amount of interest and willingness to work with it from management. We're contractors, so it depends on us finding some one who will allow us to use the language or asks for it explicitly. On Wed, Feb 10, 2010 at 10:59 AM, Jason Dusek jason.du...@gmail.com wrote: Although I'm fond of Haskell, in practice I am not a Haskell programmer -- I'm paid for Ruby and Bourne shell programming. Many of the jobs posted on this list end up being jobs for people who appreciate Haskell but will work in C# or O'Caml or some-such. I wonder how many people actually write Haskell, principally or exclusively, at work? -- Jason Dusek ___ 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] How many Haskell Engineer I/II/IIIs are there?
consider presenting at CUFP this year Any word on when this will be? On Wed, Feb 10, 2010 at 3:50 PM, Don Stewart d...@galois.com wrote: v.dijk.bas: On Wed, Feb 10, 2010 at 4:59 PM, Jason Dusek jason.du...@gmail.com wrote: I wonder how many people actually write Haskell, principally or exclusively, at work? Roel and I use Haskell at work. We develop embedded software in Haskell (not real-time) that controls a scientific instrument. We will probably write something more detailed about this project some time from now. This is a great thread. Perhaps more users could add their details to http://haskell.org/haskellwiki/Haskell_in_industry and consider presenting at CUFP this year. http://cufp.galois.com (new website to be launched soon!) -- Don ___ 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] Anyone up for Google SoC 2010?
I'll just toss this idea out there: I want to be able to pick a runtime to compile against. Some Ada compilers allow me to specify a runtime to use with a --RTS flag. This, of course, also means we'd need to write more runtime variants. I dropped this on the haskell_proposals reddit for safe keeping/evaluation: http://www.reddit.com/r/haskell_proposals/comments/azjah/pluggable_rts_for_ghc_pickyourownruntime/ /jve On Sun, Jan 31, 2010 at 6:04 AM, Malcolm Wallace malcolm.wall...@cs.york.ac.uk wrote: Google has announced that the Summer of Code programme will be running again this year. If haskell.org people would like to take part again this year, then we need volunteers: First, * suggestions for suitable projects (in the past this was organised using a reddit) * an administrator to co-ordinate the application to Google (I have done it for the last three years but am very willing to hand on to someone else) Google will accept applications from organisations in the period 8th - 12th March 2010, approx 1900UTC. If haskell.org is accepted again, students can apply between 29th March - 9th April. More volunteers will be required: * to review student applications and choose which to accept * to supervise the accepted students Both of these roles are called mentor in the Google system. Putting together a good team of mentors before applying as an organisation is helpful towards us being accepted into the programme. Regards, Malcolm ___ 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] Haskell on Ideone!
Seems a little dangerous: http://ideone.com/XL6uLnLo On Thu, Jan 21, 2010 at 8:25 PM, Gwern Branwen gwe...@gmail.com wrote: On Thu, Jan 21, 2010 at 8:02 PM, Sphere Research Labs cont...@sphere-research.com wrote: Hi, test Haskell on ideone.com, see the example: http://ideone.com/bbloQ9r0 regards, Ideone Team Besides specifying standard in, what does Ideone do beyond codepad.org? (eg. http://codepad.org/Guukn3Ho) How are you guys doing the sandboxing - just the usual chroot with rlimits? Also, the site's visual appearance is somewhat broken under firefox 3.5.7; see screenshot. -- gwern ___ 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] Force -threaded from a library
Hi List, Is it possible to prevent a library from being used unless -threaded is enabled? I have a specific case where lots-of-nasty shows up if the library is linked against an executable built without -threaded. I suppose this is GHC specific. /jve ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] what is *hack*?
http://hackage.haskell.org/package/hack 2010/1/13 Günther Schmidt gue.schm...@web.de Hi, References to a Hack. module came in the responses to my posts on HTML-GUIs. What is Hack then? Günther ___ 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] what is *hack*?
This may help more: http://wiki.github.com/nfjinjing/hack The Hack project is based off of a project known as Rack for ruby. I'm fairly sure the documentation you can find on Rack will help you understand what Hack does. 2010/1/13 Günther Schmidt gue.schm...@web.de Hi John, thanks, I should have mentioned that I had found it on hackage, I just don't understand what it *is* or what it's supposed to be for. Günther Am 13.01.10 14:46, schrieb John Van Enk: http://hackage.haskell.org/package/hack 2010/1/13 Günther Schmidt gue.schm...@web.de Hi, References to a Hack. module came in the responses to my posts on HTML-GUIs. What is Hack then? Günther ___ 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] ANNOUNCE: tuntap-0.0.1
Hi All, As some of you have requested, I've extracted the code from my (under work) VPN which talks to the TUN/TAP device under Linux (/dev/net/tun). Some things to note: 1) I've only tested this under Linux. 2) The help-win.c file under cbits HAS allowed similar code to talk to the TUN/TAP driver used by the OpenVPN project, but I haven't implemented this functionality yet. 3) The help-bsd.c file under cbits HAS allowed Mac/BSD flavors to talk to a TUN/TAP driver, but I've never tested this and haven't implemented this functionality yet. I don't have a whole lot there right now, but keep a lookout for more releases with some examples and better docs (as I get around to it). For a very verbose example, you can look at how I use the Network.TUNTAP module in this project: http://github.com/sw17ch/Scurry, specifically http://github.com/sw17ch/Scurry/blob/master/src/Scurry/TAPTask.hs. Hackage: http://hackage.haskell.org/package/tuntap GitHub: http://github.com/sw17ch/tuntap John Van Enk PS: Thanks to Matthew Isleb and Job Vranish for their help on the C code used. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Re: Data.Ring -- Pre-announce
For those interested, the version of data-clist without Empty is here: http://github.com/sw17ch/data-clist/tree/noEmpty http://github.com/sw17ch/data-clist/tree/noEmpty On Tue, Jan 5, 2010 at 2:53 AM, Luke Palmer lrpal...@gmail.com wrote: On Mon, Jan 4, 2010 at 1:13 PM, Maciej Piechotka uzytkown...@gmail.com wrote: However then we lost the monoid (ok. I haven't send patch but please accept[1]) along with alternative/monad plus - which is much more popular, standard and useful then Copointed/Comonad. This point is a self-fulfilling prophecy. We don't have very much experience working with copointeds and comonads, but I don't think that makes them useless, just unfamiliar. One must never confuse what is natural with what is habitual. -- Mahatma Gandhi Luke ___ 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] Re: Data.Ring -- Pre-announce
I've heard this a few times and am slowly becoming convinced of it. I'll try my current use without the Empty and see how it goes. Given that I've heard this from several places, I'll probably drop Empty. On Mon, Jan 4, 2010 at 9:17 AM, Luke Palmer lrpal...@gmail.com wrote: On Mon, Jan 4, 2010 at 6:51 AM, Maciej Piechotka uzytkown...@gmail.com wrote: About comonad - not exactly as every comonad is copointed and the only possible way is extract Empty = _|_ I think this module could be cleaned up by disallowing empty lists. You have this nice semantic property that every clist has a focus, but when you add empty you have to add unless it's empty. focus returns a Maybe, isEmpty is necessary. I mean, it could be that your use case requires empty clists and would be uglier without empty, but think about it. I find in Haskell that simplicity breeds simplicity; i.e. I'm willing to wager that whatever algorithm you are using clist for will actually be cleaner if you got rid of empty and modify the algorithm accordingly. We shall see though... Luke ___ 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] A question on DSL's
To start with, can you clarify that you are looking for an Embedded DSL (sometimes called Light Weight DSL)? A _proper_ DSL has its own interpreter/compiler where an EDSL/LwDSL leverages the compiler of a host language (in this case, Haskell). Assuming you're referring to an EDSL, I'll respond. :) I don't think the second option is ever used. Modifying the compiler backend doesn't seem to make a lot of sense to me. I'm not aware of any circumstance where this has been done. Your first option is closer. Generally, when emitting some sort of target code from a large EDSL, you'll have two stages. Your first takes the embedded syntax of your EDSL and converts it to an Abstract Syntax Tree. Your second stage accepts the AST as input and emits target code. Take Tom Hawkins' Atom EDSL as an example. When we write Atom code, we're building up an AST. After the AST is built up, the compile function converts the AST to C code. For smaller EDSLs, it's more than possible to have the functions themselves emit the code we're after (rather than relying on an AST and compile function). Is this what you're looking for? /jve On Mon, Jan 4, 2010 at 12:14 PM, CK Kashyap ck_kash...@yahoo.com wrote: Hi, I am not sure if I'm using DSL in the right context here but I am referring to those solutions that allow us to write code in Haskell and generate a target code source code of another language or even object code for that matter. I am aware of two ways of achieving this - 1. Implement functions that emit the target code - that is, when the Haskell code is compiled and run, the target code is emitted 2. Modify the Haskell compiler's back end to emit the code - that is when the Haskell code is compiled the target code is emitted I am not sure if there are more ways (hybrid perhaps) ... My question is, when would I chose one approach over the other? Regards, Kashyap ___ 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] Timing in atom -- how consistent?
Hi Jason, Regarding timing, the version of blink_atom.c below does not contain this, but my later versions used the hardware timers to control the blink rate. One can setup the interrupt vector for a hardware timer to call your outermost atom function at whatever resolution you want. As long as the timer allows enough time between expirations for any of the task groups to finish, it will run in hard real time. Hope this helps. John Van Enk On Thu, Dec 31, 2009 at 10:43 PM, Jason Dusek jason.du...@gmail.com wrote: I'm working with Atom to program an ATtiny25. I am curious about how consistent the timings actually are. Consider John Van Enk' example of blinking a LED on an Arduino: http://code.sw17ch.com/blog/atom/blink_atom.c We see that sometimes `setLED' is executed and sometimes not. When `__clock' is incremented, it will be incremented sometimes sooner, sometimes later. Also, I am a little puzzled by the `__coverage` variable. What does it do? As for my project/motivation -- I'm just trying to blink a little LED on much less robust/rich kit -- the Trippy RGB Waves kit from Lady Ada. I am (gratuitously) exploring ways to program it with Haskell. -- Jason Dusek ___ 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] Timing in atom -- how consistent?
I remembered that I have some of this stuff on github. Here's the example C file that sets up the timers on an Ardunio board. http://github.com/sw17ch/atom-arduino-experiments/blob/master/Blink/blink.c Notice that the main function does nothing. All the work is done by blink_atom() which is called out of the ISR (Interrupt Service Routine). On Fri, Jan 1, 2010 at 10:48 AM, John Van Enk vane...@gmail.com wrote: Hi Jason, Regarding timing, the version of blink_atom.c below does not contain this, but my later versions used the hardware timers to control the blink rate. One can setup the interrupt vector for a hardware timer to call your outermost atom function at whatever resolution you want. As long as the timer allows enough time between expirations for any of the task groups to finish, it will run in hard real time. Hope this helps. John Van Enk On Thu, Dec 31, 2009 at 10:43 PM, Jason Dusek jason.du...@gmail.comwrote: I'm working with Atom to program an ATtiny25. I am curious about how consistent the timings actually are. Consider John Van Enk' example of blinking a LED on an Arduino: http://code.sw17ch.com/blog/atom/blink_atom.c We see that sometimes `setLED' is executed and sometimes not. When `__clock' is incremented, it will be incremented sometimes sooner, sometimes later. Also, I am a little puzzled by the `__coverage` variable. What does it do? As for my project/motivation -- I'm just trying to blink a little LED on much less robust/rich kit -- the Trippy RGB Waves kit from Lady Ada. I am (gratuitously) exploring ways to program it with Haskell. -- Jason Dusek ___ 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] Timing in atom -- how consistent?
Yes, exactly. On Fri, Jan 1, 2010 at 3:02 PM, Jason Dusek jason.du...@gmail.com wrote: Wait, no -- I missed something. As long as the outermost Atom routine is run every `n' µs by a hardware clock, the counter (`__global_clock') will contain an accurate count of how many `n' µs intervals have passed in our application. -- Jason Dusek ___ 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] Data.Ring -- Pre-announce
Hi List, I recently needed a ring structure (circular list with bi-directional access) and didn't see anything obvious on Hackage. I threw something together fairly quickly and would like some feedback before tossing it on Hackage. I'd really appreciate if some one would: 1. make sure the code looks goodish (127 lines with full docs) 2. make sure my tests look saneish If I hear nothing, I'll assume wild support and push to Hackage. Code: http://github.com/sw17ch/data-ring/blob/master/src/Data/Ring.hs Tests: http://github.com/sw17ch/data-ring/blob/master/tests/quickcheck.hs Package Root: http://github.com/sw17ch/data-ring Thanks ahead of time, John Van Enk ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Data.Ring -- Pre-announce
Hi Luke, Thanks for the feedback. I had some follow up comments. On Thu, Dec 31, 2009 at 5:50 AM, Luke Palmer lrpal...@gmail.com wrote: Code looks okay. It suffers from the same persistence/amortization problem as the classical functional queue; if you happen to shift from one of the edge cases (eg. prev when the left is empty), you will get degenerate time complexity, reversing that right list over and over. See discussion at Simple and efficient purely functional queues and deques, by Chris Okasaki; probably can adapt that solution to yours. More of an academic interest, I doubt anyone will care about those cases. Yes. I agree and did see it. I'm reading the paper and may implement some of the stuff he talks about. Ring is a comonad, so you can make it an instance of one if you want to have some fun :-P I plan on adding as many instances as I know and make sense to me. :) It seems weird that you would put the focus in the middle in fromList. Overly strict. Why not just put it at the first element? (Also easier to reason about) It actually uses the first element as the focus, not the middle. I would consider considering a ring where *both* left and right were infinite to be valid, but not when only one of them is infinite (when they both are infinite, you will never get to reverse). This would be neat, perhaps someday. I don't think this works well with my current API. :( Thanks again. :) /jve ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Data.Ring -- Pre-announce
Hi Daniel, Some follow up on your comments: On Thu, Dec 31, 2009 at 5:54 AM, Daniel Fischer daniel.is.fisc...@web.dewrote: Am Donnerstag 31 Dezember 2009 10:59:54 schrieb John Van Enk: Hi List, I recently needed a ring structure (circular list with bi-directional access) and didn't see anything obvious on Hackage. I threw something together fairly quickly and would like some feedback before tossing it on Hackage. I'd really appreciate if some one would: 1. make sure the code looks goodish (127 lines with full docs) I think 'left' and 'right' aren't the optimal names. But I can't think of something clearly better either. The same applies to 'remove'. Please, flip the arguments in 'insert'. While ring `insert` el or insert ring el may seem more natural (or not) and that argument order is nicer for foldl', consistency with the argument order of Data.List.insert, Data.Set.insert and Data.Map.insert seems far more important to me. Done. 2. make sure my tests look saneish Sort of. The code is so short and clear that testing it at all may hint at paranoia. Jokes aside, prop_balance is a consequence of prop_list (toList . balance . fromList === toList . fromList . toList . fromList; toList . fromList === id == toList . fromList . toList . fromList === id). prop_isEmpty :: [Int] - Bool prop_isEmpty [] = True == (isEmpty . fromList $ []) prop_isEmpty l = False == (isEmpty . fromList $ l) prop_isEmpty [] = isEmpty . fromList $ [] prop_isEmpty l = not . isEmpty . fromList $ l or prop_isEmpty l = null l == isEmpty (fromList l) Agreed. I actually dislike all the tests... this is actually the first package I've used QuickCheck to test with. I'm most likely going to redo the test set shortly. I'll take this advice. Thanks again. /jve ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Data.Ring -- Pre-announce
Hi Heinrich, Some comments: On Thu, Dec 31, 2009 at 6:27 AM, Heinrich Apfelmus apfel...@quantentunnel.de wrote: Since the name Ring is already taken by an ubiquitous mathematical structure, and thus already in hackage for example as Algebra.Ring in the numeric-prelude , I suggest to call the data structure Necklace instead. I think I like Ring more than Necklace or Tom's suggestion of Circular. I chose Ring simply because that's what I was searching for when I wanted the data structure. The package will be named data-ring, so that should hopefully be enough to clue in the user that it's not dealing with the mathematical concept. While we're at it, I'd also perform the following name changes: -- new focus = element to the left of the current focus prev - left -- new focus = element to the right of the current focus next - right left - elementsLeft right - elementsRight The problem with prev and next is that they are relative to a default direction and everybody would have to remember whether that was to the left or right. Since a necklace is inherently symmetric, I suggest to avoid imposing such a default direction. Done. I actually had it this way first, but had the hard problem of conceptualizing left/prev right/next. I added some comments to the documentation describing the metaphor using a rotating table so that left/right make sense. Furthermore, I think the documentation is lacking a few key points, first and foremost the explanation of what exactly a Ring (Necklace) is. While you can assume that people should know what a stack or queue is, this cannot be said for this little known data structure. I hope I've addressed this in the extended documentation. Second, there is the off by one issue. Does insert put elements left or right of the focus? I've replaced insert/remove with insertL/R and removeL/R. The docs better explain their behavior. Third, I think the quickcheck tests are not very effective; instead of always converting to and from lists and testing how the operations behave, I suggest to focus on intrinsic laws, like for example (prev . next) x == x focus . insert a x == Just a and so on. (You do need one or two tests involving toList and fromList , but no more.) Yes. The tests are junk. I'm replacing them. :) Also, you should make an instance Arbitrary a = Arbitrary (Necklace a) to replace the [Int] arguments that are just a proxy for an actual necklace. (Not to mention that thanks to parametric polymorphism, it is sufficient to test everything on the lists [1..n]) Working on this now. Last but not least, what about asymptotic complexity? While your operations are usually O(1), sometimes they are O(n). You provide a function balance to deal with the latter case, but the API is much more usable if you guarantee O(1) no matter what; please dispense with balance and friends. I'll see what I can do. I'm addressing complexity after everything else looks okay. I don't like balance or pack and am hoping to drop all of them from the API. You can implement O(1) operations by using two queues instead of two lists as left and right part. Alternatively, you can adapt the rotation scheme for purely functional queues to your data structure and internally balance whenever one of the lists becomes for example 3x larger than the other one. See also chapter 3.4.2 of Chris Okasaki. Purely Functional Data Structures. (thesis) http://www.cs.cmu.edu/~rwh/theses/okasaki.pdfhttp://www.cs.cmu.edu/%7Erwh/theses/okasaki.pdf (Not sure if 3 is a good size factor; this can be determined with the amortized cost/step graph c(a) = let b = a/(1+a)-1/2 in (b+1)/b where a is the size factor.) This bothers me only because checking the length means I need to run down the spine of the list. Perhaps I can convince my self to keep a memo of the respective lengths. Thanks for your feedback! /jve ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Data.Ring -- Pre-announce
I've decided to settle on Data.CircularList. The renamed git repository is here: http://github.com/sw17ch/data-clist On Thu, Dec 31, 2009 at 3:29 PM, Twan van Laarhoven twa...@gmail.comwrote: John Van Enk wrote: Hi Heinrich, I think I like Ring more than Necklace or Tom's suggestion of Circular. I chose Ring simply because that's what I was searching for when I wanted the data structure. The package will be named data-ring, so that should hopefully be enough to clue in the user that it's not dealing with the mathematical concept. The mathematical concept would likely also go in Data, unfortunately. See for example Data.Monoid. If someone does at a Ring class sometime, it is very likely to go into Data.Ring, which would lead to conflicts. In fact it already exists, see the monoids package [1] I would prefer the name RingList or CircularList. As long as you put the word ring in the package description users will still find it when searching on hackage. [1] http://hackage.haskell.org/packages/archive/monoids/0.1.25/doc/html/Data-Ring.html Twan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Announce: data-clist-0.0.3 -- A RingBuffer/CircularList/Ring data type
Hi all, data-clist-0.0.3 is up on hackage: http://hackage.haskell.org/package/data-clist-0.0.3 Any feedback is appreciated. The docs are getting there, but not quite complete. Enjoy! /jve ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Memory-aware Haskell?
This is a problem with partitioned operating systems used in avionics. The airplane computers require certain partitions to exist between programs in both time and space. The space guarantees are most easily enforced by eliminating any dynamic memory allocation once the operating system enters a 'normal mode'. This means that all memory needs to be allocated on the stack and ahead of time. This reduces the calculation of the upper memory bound to checking what the largest possible stack a process could grow to is. Of course, calculating this maximum stack is difficult in its own right. Unfortunately, nothing I've just discussed seems to port well to Haskell (I could be wrong!). Given this, I think you're looking at a very hard problem (but one I'd be incredibly interested in discovering a solution for!). /jve On Thu, Dec 24, 2009 at 5:38 PM, Roman Cheplyaka r...@ro-che.info wrote: Imagine some system with hard memory bound (e.g. 64M of physical memory, no swap). I don't want some accidental laziness (maybe even not in my code, but in some used package) to crash my program. So, let's think what we can do at runtime. Suppose RTS takes the parameter -- upper limit of consumed memory. When it sees that memory consumption is close to upper bound, it can: 1. force garbage collection 2. apply some heuristics to find and reduce some chunks which will benefit from reduction in terms of size 3. if nothing helps, throw an exeption. It can be caught in IO and memory-aware program can make apropriate decision -- e.g. abort opening a large file and gracefully warn the user. (And there still is a problem of foreign code whose memory consumption we know nothing about...) What do you think? -- Roman I. Cheplyaka :: http://ro-che.info/ Don't let school get in the way of your education. - Mark Twain ___ 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] ANN: Hemkay, the 100% Haskell MOD player
It's been well over a year. I'll see what I can do when I get some free(er) time. 2009/12/14 Patai Gergely patai_gerg...@fastmail.fm The more of these I see, the more guilt I feel over the condition of the portaudio module. There's a good chance that the performance issue you're seeing is a bad implementation of the portaudio library. Do you have any specific problems you ran into with portaudio? I'd love to revisit at some point... Well, when I tried to push whole blocks instead of individual samples, it seemed to miss some of these writes. It might do the same even now, but it wouldn't be noticeable with a sample missing here and there anyway. The interface for writeStream is not very fortunate. It forces me to pack samples into lists no matter what, even if the interleaved list is actually easier to produce. So it should probably provide alternative interfaces for interleaved lists (which would actually be possible right away if writeStream didn't ignore its third argument altogether), and maybe an array interface as well. I don't know if the callback interface works better, maybe that's also worth a shot. Ultimately, it would be probably best if it gave the programmer a higher abstraction, where it is passed a potentially infinite list of samples, and takes care of all the buffering duties. Also, this could be made to play nice with stream fusion in order to get the maximum performance out of it. Gergely -- http://www.fastmail.fm - One of many happy users: http://www.fastmail.fm/docs/quotes.html ___ 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] Re: Why?
If anything, I'd flip those two... On the backend, things are anything but pure but it helps us reason about the program on the front end. Laziness also isn't nearly as prevalent on the backend as it is on the front end. Even though we can reason about things using purity and laziness on the front, the compiler often times makes an identical situation that runs a lot faster using strictness and mutation on the back. /jve On Thu, Dec 10, 2009 at 11:09 AM, John D. Earle johndea...@cox.net wrote: Laziness is on the logic front end and purity is on the execution back end. ___ 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] Rebox Package or To Hackage or not to Hackage
Hi List, I've recently had a situation where I used the same pattern quite a bit while reducing and evaluating an AST. I quickly wrapped the operation in a package and stuck it on github. http://github.com/sw17ch/rebox/blob/master/src/Data/Rebox.hs I'm wondering two things: 1) Does any one recognize the pattern I'm using here as something with a different name? 2) Is this worth sticking on Hackage? It's trivial, but we have plenty of trivial concepts on Hackage (and it's not a bad thing). Any feedback would be great. /jve ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: ANNOUNCE: PortAudio Windows Tutorial and Binaries
Very cool. On Sun, Dec 6, 2009 at 7:29 PM, M Xyz functionallyharmoni...@yahoo.comwrote: I got a lot of great help this weekend from Haskell-Cafe, thanks. Now that I have portaudio up and running I put up a tutorial and a 103 kb download of all the windows binaries and files. I hope this helps people exploring digital audio with Haskell. http://www.subreddits.org/misc/haskell/portaudio.html ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Low Level Audio - Writing bytes to the sound card?
Hi, portaudio is my embarrassing fault, but it does work most of the time. (Community, some one remind me to revisit this package after Christmas.) Are you running in Windows? Linux? If Linux, which flavor? /jve On Fri, Dec 4, 2009 at 1:51 PM, M Xyz functionallyharmoni...@yahoo.comwrote: What is the most minimal (preferably platform independent) library available for writing bytes to the sound card? I see 60 wonderful libraries on Hackage, but I really just need the Haskell equivalent of an audio.write(byte[]) method. What sound api are these 60 libraries using? I think the portaudio library is the only contender but when I try to install it I get: cabal install portaudio Resolving dependencies... Downloading portaudio-0.0.1... Configuring portaudio-0.0.1... cabal: Missing dependency on a foreign library: * Missing C library: portaudio This problem can usually be solved by installing the system package that provides this library (you may need the -dev version). If the library is already installed but in a non-standard location then you can use the flags --extra-include-dirs= and --extra-lib-dirs= to specify where it is. cabal: Error: some packages failed to install: portaudio-0.0.1 failed during the configure step. The exception was: exit: ExitFailure 1 ___ 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] Low Level Audio - Writing bytes to the sound card?
You'll have to install the portaudio C libraries and header files before continuing. I never actually tested the package on XP, if you get it to work, I'd love to hear your experience. /jve On Fri, Dec 4, 2009 at 2:20 PM, M Xyz functionallyharmoni...@yahoo.comwrote: Hi, portaudio is my embarrassing fault, but it does work most of the time. (Community, some one remind me to revisit this package after Christmas.) Are you running in Windows? Linux? If Linux, which flavor? /jve I'm using Haskell on XP but I dual boot with Ubuntu 9 and I'd prefer not to break compatibility. I'm new to this, was I supposed to install portaudio for my OS before downloading the Haskell package? Are there other similar simple sound apis? On Fri, Dec 4, 2009 at 1:51 PM, M Xyz functionallyharmoni...@yahoo.comhttp://mc/compose?to=functionallyharmoni...@yahoo.com wrote: What is the most minimal (preferably platform independent) library available for writing bytes to the sound card? I see 60 wonderful libraries on Hackage, but I really just need the Haskell equivalent of an audio.write(byte[]) method. What sound api are these 60 libraries using? I think the portaudio library is the only contender but when I try to install it I get: cabal install portaudio Resolving dependencies... Downloading portaudio-0.0.1... Configuring portaudio-0.0.1... cabal: Missing dependency on a foreign library: * Missing C library: portaudio This problem can usually be solved by installing the system package that provides this library (you may need the -dev version). If the library is already installed but in a non-standard location then you can use the flags --extra-include-dirs= and --extra-lib-dirs= to specify where it is. cabal: Error: some packages failed to install: portaudio-0.0.1 failed during the configure step. The exception was: exit: ExitFailure 1 ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://mc/compose?to=haskell-c...@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] Finding HP
I'm all for making HP the default as long as we find a way to make some of the larger packages (I'm thinking gtk2hs) either ship with HP in Windows or install correctly with HP. On Thu, Dec 3, 2009 at 11:46 AM, Joe Fredette jfred...@gmail.com wrote: I think it makes sense, the HP is supposed to set up the entire environment needed for typical haskell development (at least, that is my understanding). As such, what's the point in making downloading haskell mean downloading a single _peice_ of haskell (GHC) only to have to download _everything else anyway_ (cabal-et-al, various standard libraries, etc). Perhaps we could put it to some kind of community vote. /Joe On Dec 3, 2009, at 11:43 AM, Don Stewart wrote: vandijk.roel: On Wed, Dec 2, 2009 at 11:44 PM, Gregory Crosswhite gcr...@phys.washington.edu wrote: On a more serious note, Download Haskell /= Download Haskell Platform, so if I were glancing down the sidebar looking for a link to download the Haskell Platform then the first link wouldn't have registered for me. And putting a X has been released link! in the news does not count as a prominent download link. If I wanted to know something *about* the *Haskell Platform* I would click the link The Haskell Platform under the section About. So it is actually mentioned 3 times on the front page. What could be improved are the 2 download links: Download Haskell and Download GHC. It would perhaps be better to have one nice big Download button that takes you to a separate download page. Having a single download link that only points to the Haskell Platform would be a bit of a policy shift. Is the community ready to accept that users looking for Haskell should be given the HP binaries? If so, I can change it to have a single Download button. Though it might be preferable to do that after the next release (the first non-beta release). -- Don ___ 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] Is Haskell a Fanatic?
The burden of proof is on you to demonstrate that it _is_. On Thu, Dec 3, 2009 at 12:09 PM, John D. Earle johndea...@cox.net wrote: See [Haskell-cafe] Optimization with Strings ? for background. Don Stewart wrote, the guarantees of purity the type system provides are extremely useful for verification purposes. My response to this is in theory. This is what caught my attention initially, but the language lacks polish and does not appear to be going in a direction where it shows signs where it will self-correct. It may even be beyond repair. I care about others and I don't want people to be misled. I am already well aware of the numbers. They do not impress me. I have written on this already. I have given Haskell the benefit of the doubt and said, What's wrong with being uncompromising? There is something wrong with it, if it has taken you off the path of truth. This is not uncompromising. This is something else. It is called fanaticism and this is the opinion that I have come to after due consideration. If you are going to argue your case, be constructive. Tell me how the type system is not flawed and how the Haskell language is rigorous. What proof do you have of this? Explain to me how Haskell has been merely uncompromising in its pursuit of perfection and did not manage to step over the threshold into fanaticism. Please remain on topic and on point. ___ 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] Is Haskell a Fanatic?
*flawed, that is On Thu, Dec 3, 2009 at 12:13 PM, John Van Enk vane...@gmail.com wrote: The burden of proof is on you to demonstrate that it _is_. On Thu, Dec 3, 2009 at 12:09 PM, John D. Earle johndea...@cox.net wrote: See [Haskell-cafe] Optimization with Strings ? for background. Don Stewart wrote, the guarantees of purity the type system provides are extremely useful for verification purposes. My response to this is in theory. This is what caught my attention initially, but the language lacks polish and does not appear to be going in a direction where it shows signs where it will self-correct. It may even be beyond repair. I care about others and I don't want people to be misled. I am already well aware of the numbers. They do not impress me. I have written on this already. I have given Haskell the benefit of the doubt and said, What's wrong with being uncompromising? There is something wrong with it, if it has taken you off the path of truth. This is not uncompromising. This is something else. It is called fanaticism and this is the opinion that I have come to after due consideration. If you are going to argue your case, be constructive. Tell me how the type system is not flawed and how the Haskell language is rigorous. What proof do you have of this? Explain to me how Haskell has been merely uncompromising in its pursuit of perfection and did not manage to step over the threshold into fanaticism. Please remain on topic and on point. ___ 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] IORefs and weak pointers
Is the IORef or the value in the IORef your key? 2009/11/2 Patai Gergely patai_gerg...@fastmail.fm Hello all, I wanted to create a weak pointer with an IORef as the key and something else as the value, but I saw no way to do it through the API provided. After some experimentation I came up with the following abomination for a solution: myWeakRef (IORef (STRef r)) v f = IO $ \s - case mkWeak# r v f s of (# s', w #) - (# s', Weak w #) This works perfectly when the code is compiled both with and without optimisations, but ghci chokes on it with an internal error. So my question is if I can expect this to work at least this much in the long run, or is it a hopelessly fragile hack? Gergely -- http://www.fastmail.fm - Same, same, but different... ___ 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] ANN: mecha-0.0.0
Is this on hackage yet, or should we just consult the mecha link on your home page? On Wed, Oct 21, 2009 at 11:42 PM, Tom Hawkins tomahawk...@gmail.com wrote: A few months ago, I started toying with a few alternative pump designs to power our hydraulic hybrids. After not being able to secure a ProE license, I searched for a free solid modeler to sketch out a few ideas. To my surprise, their are practically no open source 3D CAD packages available. So I created Mecha, DSL for constructive solid modeling. Mecha's geometry is based on octrees, which makes it easy to perform set operations on solids, as well as volumetric calculations such as center-of-mass, moments of inertia, and of course, total volume. Drawbacks of octrees include consuming a lot of memory and the loss of some surface information. To address the later, Mecha carries forward surface points and normals to the leaf nodes of the octree to assist in rendering, such that solids don't look like they're made from a bunch of LEGOS. Note this is a very early release. The only thing Mecha can do at the moment is draw a pretty blue ball -- well it can also zoom and pan on a pretty blue ball (mouse wheel). Establishing a primitive API and building a primitive library must be finished before Mecha an do anything useful. Any comments and suggestions are welcome. http://tomahawkins.org/ ___ 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] Make two windows work together
Are you using GTK? OpenGL? Haskell? There's absolutely no context here... On Tue, Oct 20, 2009 at 11:02 AM, xu zhang douy...@gmail.com wrote: Hi there, I am trying to make a sub-window of one window and make them work together. I mean, if I zoom or transform some content in one of the window, the other one works in the same way. What I have done so far is just open a new window which have the same drawing view as the original one, but when I try to change some content in one window, the other one does not work at the same time. They are separate. Can anyone give me some hint on how to make them work at the same time not separate anymore? Thank you so much! ___ 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] Need help with ghc static compile for cgi using mysql
I've run Haskell stuff on VPS hosts like Linode or SliceHost. $20/month is a lot better than $60. On Thu, Oct 15, 2009 at 12:32 PM, Austin King sh...@ozten.com wrote: For now, I've given up on cheap hosting (via statically compiled CGI). I've created a GHC 6.10.4, cabal-install, Ubuntu 9.04 ec2 instance + MySQL and it works well. Running this plus EBS and Elastic IP will run a little over $60 a month. Ouch. The work going into Haskell Platform is amazing, but... Haskell needs a better commodity hosting story, to allow for casual, fun web hacking. For the record, I tried nearlyfreespeech.net and dreamhost. I wasn't able to install ghc and cabal due to: * FreeBSD GHC support (old version) * FreeBSD library support (no HDBC) * Linux - Missing 'dev' libraries like zlib and not having root access ___ 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] On DSLs - one last time
To me, the D and S come in when I'm deciding what to support. The domain represents the set of primitive operations I want to support. The specific says that I don't support anything other than those operations. Consider a language for laying out boolean logic circuits: we want to implement only AND, OR, and XOR, and NOT. The domain is boolean logic. We can't reason directly about trees or rainbows with this language, so it's specific. Our set of primitive operations would probably consist of: 1) Create input 2) Perform one of AND, OR, or XOR on two inputs (or proceeding inputs from previous operations) 3) Apply a NOT to an operation. With this basic set of operations, one can build up a graph of gates which can then be executed directly, converted to some other intermediate form, or plotted in graphical form. This is actually the focus domain of a small EDSL I'm working on for demonstrative purposes. The following is a link to the github repository and a direct link to one of the examples. http://github.com/sw17ch/gator http://github.com/sw17ch/gator/blob/master/examples/4bitAdder.hs The example linked is a 4 bit adder (8 inputs, 4 outputs) that will dump GraphViz 'dot' code. This simple EDSL currently only allows you to construct graphviz, but the intermediate Logic type could be transformed to just about anything having to do with boolean logic or executed in place. I hope some of this made sense. /jve 2009/10/8 Günther Schmidt gue.schm...@web.de Hi all, I'd like to summarize my impressions on the DSL issue, gathered from the responses to my posts. It is absolutely amazing, various people have shown here that it is possible to design languages within haskell that are almost or just as powerful and safe as haskell itself. It is probably even possible to create an EDSL within an EDSL within haskell. Amazing! Uhm... ... but in that case I really wonder why I should not use Haskell directly then. Because out of the EDSL I can clearly see the E and I can see the L but having slight problems figuring out where the D and the S come in. In short, yes it's great that you can create a language within Haskell so powerful that it's gone full circle and is general purpose again, but what good is that? The efforts I've seen here where efforts to create a rich and powerful syntax, but aren't we supposed to focus on expressing semantics specific to a problem in a DSL rather? I'm not trying to put the efforts and achievements of the people who have done such amazing work down, but what exactly is it that I missed? Günther ___ 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] Re: What *is* a DSL?
On Wed, Oct 7, 2009 at 2:52 PM, Ben Franksen But isn't one of the advantages of an _E_DSL that we can use the host language (Haskell) as a meta or macro language for the DSL? Substantially so. I've used brief examples where the EDSL syntax is basically the data declaration (perhaps with some operators overloading constructors) to demonstrate Haskell's fitness as a host language for EDSLs. This is also a credit to the expressiveness of Haskell's data declarations. /jve ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Cabal - how do I remove a package?
you want: ghc-pkg unregister [package name] and ghc-pkg list /jve On Tue, Oct 6, 2009 at 3:52 PM, Paul Moore p.f.mo...@gmail.com wrote: As it says in the subject, how do I remove a package that I installed (with the --user flag) via cabal? Come to that, how do I list the packages I've installed via cabal? cabal list --installed includes all the GHC standard library (which I didn't install) and it doesn't seem to support a --user flag to list per-user installed packages. FWIW, I'm on Windows 7. Thanks, Paul. ___ 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] Cabal - how do I remove a package?
Are you actually trying to remove the bits from the hard drive, or is that something to fix a different problem you're having. If it's a different problem, perhaps you could ask that as well? On Tue, Oct 6, 2009 at 4:04 PM, Paul Moore p.f.mo...@gmail.com wrote: 2009/10/6 John Van Enk vane...@gmail.com: you want: ghc-pkg unregister [package name] and ghc-pkg list Thanks. I wouldn't have found that by myself. Unfortunately, having issued ghc-pkg unregister mersenne-random-1.0 I still see the code present: dir C:\Users\Gustav\AppData\Roaming\cabal\mersenne-random-1.0\ghc-6.10.4 Volume in drive C is OS Serial number is 8442:99ea Directory of C:\Users\Gustav\AppData\Roaming\cabal\mersenne-random-1.0\ghc-6.10.4\* 05/10/2009 21:06 DIR. 05/10/2009 21:06 DIR.. 05/10/2009 21:06 DIRinclude 05/10/2009 21:06 DIRSystem 05/10/2009 21:06 44,350 HSmersenne-random-1.0.o 05/10/2009 21:06 66,762 libHSmersenne-random-1.0.a Looks like ghc-pkg unregister just does precisely that - unregisters the package but doesn't remove it. Can I even persuage cabal/ghc-pkg to list all the files and directories created by the install so I can remove them by hand? Paul. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Market Place for Haskell development teams?
Sorry boss, but we're just not going to be able to meet that deadline, because, well, a language extension we were using was dropped from the language, and the syntax for some core operators was changed. Not only is our code broken, but many of the libraries we were using are broken. Don't worry, though, we're 'agile', so our unit tests will tell us when our code is working again. Big business demands stability. And yet they use IE... how many projects have I had to spend substantial time fixing because Microsoft releases a new IE... ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] c2hs, size_t, and CSize -- argh!
Hello List, I'm running into a problem with c2hs and how it parses the C typedef 'size_t'. On 32bit systems, this ends up being parsed as a CUInt. On 64bit systems, this ends up as a CULong. This gets especially sticky with function pointers. In order to make bindings with c2hs that work across the different word sizes, I have to write an indirection layer in C that defines wrappers for functions or re-defines typedef's for function pointers to include 'unsigned long' instead of 'size_t'. I see there is a ticket open for this: http://hackage.haskell.org/trac/c2hs/ticket/20 Has any one else run into this issue? Is there a good workaround that doesn't involve writing a C function/typedef for each collision? /jve ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] c2hs, size_t, and CSize -- argh!
Hi Duncan,
Yes, I forgot to leave out that I'd like to see 'size_t' mapped to CSize.
As a (dirty) workaround, one can use 'castPtr' as the marshaler when dealing
with pointers to 'size_t'. I'm a little more concerned about FunPtr's
(though 'castPtr' still makes the issue go away).
Here's my specific case dealing with function pointers:
In 64bit world, it looks like this:
type ReadableCallback = Ptr () - Ptr CUChar - *Ptr CULong* - IO CUInt
{#fun gcry_ac_io_init_readable_callback {
id `ACIO',
id `FunPtr ReadableCallback',
id `Ptr ()'
} - `()'#}
In 32bit world, it looks like this:
type ReadableCallback = Ptr () - Ptr CUChar - *Ptr CUInt* - IO CUInt
{#fun gcry_ac_io_init_readable_callback {
id `ACIO',
id `FunPtr ReadableCallback',
id `Ptr ()'
} - `()'#}
I'd really like it if I could use 'Ptr CSize' (which corresponds to the
'size_t * ptr' in the C code).
My current workaround (which doesn't use a cast in Haskell) is to redefine
the function pointer type in a C header file to use 'unsigned long' instead
of 'size_t', but this gets cludgy in a hurry. If c2hs could translate to
CSize directly, I could pass a pointer to CSize.
Is it really such a problem to make the conversion? My assumption is that
CSize would match 'size_t' for the specific architecture.
Thanks for your comment.
/jve
On Thu, Oct 1, 2009 at 12:37 PM, Duncan Coutts duncan.cou...@googlemail.com
wrote:
On Thu, 2009-10-01 at 10:20 -0400, John Van Enk wrote:
Hello List,
I'm running into a problem with c2hs and how it parses the C typedef
'size_t'. On 32bit systems, this ends up being parsed as a CUInt. On
64bit systems, this ends up as a CULong. This gets especially sticky
with function pointers.
Right. Of course that's because on those different platforms size_t
really is a typedef for unsigned int or unsigned long.
I see there is a ticket open for this:
http://hackage.haskell.org/trac/c2hs/ticket/20
Has any one else run into this issue? Is there a good workaround that
doesn't involve writing a C function/typedef for each collision?
So what you would want, presumably, is to map the size_t typedef to
the Haskell type Foreign.C.Types.CSize, rather than what c2hs discovers
as the actual raw type of size_t. Then you're making the promise that
unsigned long, or unsigned int really really does match
Foreign.C.Types.CSize.
Currently c2hs has no support for remapping basic types like that.
As for a workaround, just use fromIntegral to convert to CSize. You know
this is always possible because you know CSize matches CUInt or CULong
on the appropriate platforms.
$ cat foo.h
#include stddef.h
size_t foo(void);
$ cat foo.c
#include foo.h
size_t foo(void) { return 42; }
$ cat foo.chs
import Foreign.C.Types
foo :: IO CSize
foo = fmap fromIntegral {# call foo as bar #}
$ gcc -c foo.c
$ c2hs foo.h foo.chs
$ ghci foo.hs -fffi foo.o
Main foo
42
Duncan
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Re: [Haskell-cafe] c2hs, size_t, and CSize -- argh!
Ohhh, if you're dealing with pointers to CSize then it's easy, c2hs
supports that directly. See the c2hs user guide section on the pointer
hook.
{# pointer *size_t as CSizePtr - CSize #}
I seriously should have thought of that. I have #pointer's everywhere, but I
didn't think to do it with that. Thanks.
/jve
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Re: [Haskell-cafe] Status of GHC as a Cross Compiler
Thanks. I'd heard rumors about a year ago that 6.12 might have a cross compiler. I just wanted to check. :) On Wed, Sep 23, 2009 at 4:41 PM, Duncan Coutts duncan.cou...@worc.ox.ac.ukwrote: On Wed, 2009-09-23 at 14:50 -0400, John Van Enk wrote: Hi, This may be more appropriate for a different list, but I'm having a hard time figuring out whether or not we're getting a cross compiler in 6.12 or not. Can some one point me to the correct place in Traq to find this information? We're getting slightly closer but it's not even nearly there yet. You might have read about the changes in the native code generator towards building all backends on each platform. However there are a lot of other changes needed especially in the build system to make a full cross-compiler. I know some people have worked on this for ARM but there's nothing integrated yet. Duncan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Status of GHC as a Cross Compiler
Hi, This may be more appropriate for a different list, but I'm having a hard time figuring out whether or not we're getting a cross compiler in 6.12 or not. Can some one point me to the correct place in Traq to find this information? /jve ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ANNOUNCE: hssqlppp, sql parser and type checker, pre-alpha
Second the hackage suggestion. `cabal unpack [package name]` is a really nice way to grab sources. On Mon, Sep 14, 2009 at 1:59 PM, Don Stewart d...@galois.com wrote: jakewheatmail: Hello all, I've started on a SQL parser and type checker, which I'm currently planning on evolving into a lint-type program for PL/pgSQL, called HsSqlPpp. It currently parses a subset of PostGreSQL SQL and PL/pgSQL, can type check some select, insert, update, delete and create statements, and is pretty rough all round at the moment. It uses Parsec and UUAGC, comes with a small HUnit test suite, and has a Cabal file. The code is on Launchpad here: https://launchpad.net/hssqlppp You can get a snapshot here: http://launchpad.net/hssqlppp/prealpha/secondtypechecking/+download/hssqlppp-140909-rev276.zip More information in the readme: http://bazaar.launchpad.net/~jakewheat/hssqlppp/trunk/annotate/head%3A/READMEhttp://bazaar.launchpad.net/%7Ejakewheat/hssqlppp/trunk/annotate/head%3A/README and brief the usage guide gives you an idea of what you can do with it right now: http://bazaar.launchpad.net/~jakewheat/hssqlppp/trunk/annotate/head%3A/usagehttp://bazaar.launchpad.net/%7Ejakewheat/hssqlppp/trunk/annotate/head%3A/usage I'm pretty new to Haskell, parsing, attribute grammars and type checking - any comments, advice, criticism welcome. Will you be releasing it on Hackage? Bonus: if you do, it can be cabal-installed :) -- Don ___ 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] Announce: EnumMap-0.0.1
I'll hunt down those changes and push something new to hackage. :) On Mon, Sep 14, 2009 at 12:27 PM, Felipe Lessa felipe.le...@gmail.comwrote: On Wed, Aug 12, 2009 at 01:03:55PM -0400, John Van Enk wrote: EnumMap silently passes this responsibility to the user, without even a note in the documentation. Like I've said, I made no modifications to the documentation other than replacing IntMap with EnumMap. Should the community show more interest in the EnumMap, such a change will show up in the docs. I'm showing interest in EnumMap :). I have some IntMap's that provide no type safety about what is inserted and EnumMap solves that problem as nicely as possible. Right now I don't really care about the doumentation problems, but I would like to see the SPECIALIZE and INLINE improvements, when will there be a new version? Thanks a lot! -- Felipe. ___ 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] Announce: EnumMap-0.0.1
http://hackage.haskell.org/package/EnumMap Changes pushed. Job Vranish added the SPECIALIZE pragmas, and I believe he has more data concerning how much this helps. Note, the git repo is here: http://github.com/sw17ch/EnumMap /jve On Mon, Sep 14, 2009 at 12:27 PM, Felipe Lessa felipe.le...@gmail.comwrote: On Wed, Aug 12, 2009 at 01:03:55PM -0400, John Van Enk wrote: EnumMap silently passes this responsibility to the user, without even a note in the documentation. Like I've said, I made no modifications to the documentation other than replacing IntMap with EnumMap. Should the community show more interest in the EnumMap, such a change will show up in the docs. I'm showing interest in EnumMap :). I have some IntMap's that provide no type safety about what is inserted and EnumMap solves that problem as nicely as possible. Right now I don't really care about the doumentation problems, but I would like to see the SPECIALIZE and INLINE improvements, when will there be a new version? Thanks a lot! -- Felipe. ___ 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] Cabal install on Windows 7
Might it make sense to try and get the concept of global and user working in Windows? (It may already, but I noticed that the default seems to be global.) I don't know what technical challenges there are, but the ApplicationData directory (or AppData, or whatever) seems like a good place to stick user cabal packages. /jve On Tue, Sep 8, 2009 at 9:31 AM, Peter Verswyvelen bugf...@gmail.com wrote: I tried the cabal install command on Windows 7, and I had to run it with administrative privileges, otherwise I got access denied (it failed to create the Haskell folder in C:\Program Files) Not sure if this is also the case on Vista. Is this the intended behavior? ___ 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] ANN: jail-0.0.1 - Jailed IO monad
Neat! On Thu, Aug 27, 2009 at 10:09 AM, Sebastiaan Visser sfvis...@cs.uu.nlwrote: Hi all, I am very pleased to announce the first release of the jail[1,2] package. A jailed IO monad that can restrict filesystem access for your code. This package will soon be an integral part of the Salvia web server. (a new and improved Salvia will be released soon) Basic documentation of the jail package is included below. Any comments, suggestions, audits, etc. are welcome! Gr, -- Sebastiaan Visser [1] Source repo: http://github.com/sebastiaanvisser/jail/ [2] Hackage: http://hackage.haskell.org/package/jail Like all of us know, the IO monad from the System.IO module is a wild beast allowing all forms of insecure computations that can read, or even worse, alter the real world. Writing to sockets, deleting files or even launching missiles, its possibilities are endless. This library provides a special IO module that wraps all file and handle based IO operations from the System.IO module, but provides a possibility to run them in an restricted environment. When running a jailed IO computation a file path can be specified all IO operations will be checked against. Accessing files outside this directory is not allowed and results in a runtime error. Additionally, when running a jailed IO computation a whitelist of file handles can be specified that are accessible as well. For example, running some code with the permission to access all files within (and only within) my home directory and allowing to access the standard output and standard error can be enforced like this: Jail.run (Just /home/sebas) [stdout, stderr] yourUntrustworthyComputation Only allowing the code to access the standard input and nothing else can be enforced like this: Jail.run Nothing [stdin] yourEvenMoreUntrustworthyComputation Because the jailed IO environment keeps track of all file handles and checks that are opened by its own operations, smuggling in evil file handles from the fierce and dangerous outside world will be punished by border patrol. Only handles from the whitelist or handles securely opened by functions like openFile will be accepted. Because of the opaque IO constructor and the restricted set of exported operations this module is not easily fooled. I would almost dare to say this module is conceptually safe and code with the jailed IO type can blindly be trusted. Except, yes unfortunately except, unsafePerformIO ruins it all. I would almost suggest adding a flag to the compiler to enforce the absence ofunsafeRuinMyTypeSafety-alike functions in order to be able to create systems in which code can be trusted by its type alone. Nonetheless, this module is one step forward in trusting your own programs. Some real http://tinyurl.com/paranoidpeople prefer writing there software in one of the most insecure programming languages and perform security audits by hand, I'd rather have my compiler do the job. (Anyone who wants to audit this library is more than welcome!) ___ 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] Killing a thread blocking on a foreign call
Hi List, I'm trying to kill a thread (during program cleanup) that is almost always going to be perma-blocking on a foreign call (read). It seems that there's no facility to do this built into Haskell at this point, or is there? /jve ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announce: EnumMap-0.0.1
On Wed, Aug 12, 2009 at 2:09 AM, Ketil Maldeke...@malde.org wrote: Felipe Lessa felipe.le...@gmail.com writes: There are some funky Enum instances around: IMO it's implicit that keys overwrite eachother whenever their 'fromEnum' is equal, however that may be spoken in the docs. I couldn't find anything explicit in the documentation. I'd suggest a clear note at the top, dismissing the (IMO natural) notion that EnumMap k v behaves like Map k v (which was true for IntMap and Map Int, I believe). I haven't updated any of the documentation from IntMap over s/IntMap/EnumMap/g. And perhaps also note that you will get exceptions for values outside the Enum range. I'd think that part is obvious. It strikes me that using Bits instead of Enum might be more likely to be what people want in many cases - but perhaps that would be too slow? Also that Enum really should map to Integer, but again, that's a speed issue.¹ I think Enum is a little more natural--perhaps I'm wrong. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announce: EnumMap-0.0.1
On Wed, Aug 12, 2009 at 11:34 AM, David Menendezd...@zednenem.com wrote: On Wed, Aug 12, 2009 at 9:16 AM, John Van Enkvane...@gmail.com wrote: On Wed, Aug 12, 2009 at 2:09 AM, Ketil Maldeke...@malde.org wrote: And perhaps also note that you will get exceptions for values outside the Enum range. I'd think that part is obvious. That depends on what outside the Enum range means. You'll get an exception if you somehow get an Int key in the map which doesn't correspond to any value in the enum... We should be protected by the type system against unmatched Int's in the map as long as you have sane Enum instances. ... but you don't get an exception if you try to pass in, say, a large Integer. Prelude fromEnum (2^32) 0 In essence, you're using Enum as a hash function, but not making any provision for hash collisions. Unless I'm mistaken, the Enum typeclass _is_ a hash function who's keyspace is the range of Int that doesn't make any provisions for collisions. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announce: EnumMap-0.0.1
EnumMap silently passes this responsibility to the user, without even a note in the documentation. Like I've said, I made no modifications to the documentation other than replacing IntMap with EnumMap. Should the community show more interest in the EnumMap, such a change will show up in the docs. On Wed, Aug 12, 2009 at 12:58 PM, David Menendezd...@zednenem.com wrote: On Wed, Aug 12, 2009 at 12:07 PM, John Van Enkvane...@gmail.com wrote: On Wed, Aug 12, 2009 at 11:34 AM, David Menendezd...@zednenem.com wrote: On Wed, Aug 12, 2009 at 9:16 AM, John Van Enkvane...@gmail.com wrote: On Wed, Aug 12, 2009 at 2:09 AM, Ketil Maldeke...@malde.org wrote: And perhaps also note that you will get exceptions for values outside the Enum range. I'd think that part is obvious. That depends on what outside the Enum range means. You'll get an exception if you somehow get an Int key in the map which doesn't correspond to any value in the enum... We should be protected by the type system against unmatched Int's in the map as long as you have sane Enum instances. One would hope so. ... but you don't get an exception if you try to pass in, say, a large Integer. Prelude fromEnum (2^32) 0 In essence, you're using Enum as a hash function, but not making any provision for hash collisions. Unless I'm mistaken, the Enum typeclass _is_ a hash function who's keyspace is the range of Int that doesn't make any provisions for collisions. Hash functions traditionally map integers to integers, so I would describe fromEnum as like a hash function, but that's not important. And yes, hash functions collide, which is why hash tables employ various methods for distinguishing keys that hash to the same values. EnumMap silently passes this responsibility to the user, without even a note in the documentation. -- Dave Menendez d...@zednenem.com http://www.eyrie.org/~zednenem/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announce: EnumMap-0.0.1
It strikes me that using Bits instead of Enum might be more likely to be what people want in many cases It wouldn't hurt for you (or someone) to implement this. I'm sure it would be useful. On Wed, Aug 12, 2009 at 2:09 AM, Ketil Maldeke...@malde.org wrote: Felipe Lessa felipe.le...@gmail.com writes: There are some funky Enum instances around: IMO it's implicit that keys overwrite eachother whenever their 'fromEnum' is equal, however that may be spoken in the docs. I couldn't find anything explicit in the documentation. I'd suggest a clear note at the top, dismissing the (IMO natural) notion that EnumMap k v behaves like Map k v (which was true for IntMap and Map Int, I believe). And perhaps also note that you will get exceptions for values outside the Enum range. It strikes me that using Bits instead of Enum might be more likely to be what people want in many cases - but perhaps that would be too slow? Also that Enum really should map to Integer, but again, that's a speed issue.¹ One could also question the sanity of using e.g. floating point values as keys, but Map supports this, so who am I to judge. (Also, a minor documentation niggle is that Haskell only guarantees 30 bits for an Int, it's GHC that uses Ints of 32 and 64 bits. One could argue that it is the report that should be fixed here, unless one can imagine a program that depends on correct modulo arithmetic with an unknown quotient.) -k ¹ This of course migth give the careless reader of the Report the impression that the Haskell community values speed over correctness, and thus that we actually are aiming for popularity and mainstream recognition after all. -- If I haven't seen further, it is by standing in the footprints of giants ___ 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] unsafeDestructiveAssign?
unsafeHorribleThings I think we have a name for this new feature. I can see how something like this would be useful to some areas. There are many cases (graphs!) where it's just easier to build up structures destructively, seal them, and return them to happyPureFunTimesLand. Even if GHC does do just as good of a job as performing the unsafe button pushing our selves, it would be an interesting exercise. On Tue, Aug 11, 2009 at 12:14 PM, Max Desyatovexplicitc...@googlemail.com wrote: Job Vranish jvran...@gmail.com writes: Does anybody know if there is some unsafe IO function that would let me do destructive assignment? Something like: a = 5 main = do veryUnsafeAndYouShouldNeverEveryCallThisFunction_DestructiveAssign a 8 print a 8 Aren't StateT or IORefs the exact thing you are looking for? I'm also looking for a way to make actual copies of data. so I could do something like this: a = Node 5 [Node 2 [], Node 5 [a]] main = do b - makeCopy a veryUnsafeAndYouShouldNeverEveryCallThisFunction_DestructiveAssign b (Node 0 []) -- 'a' is unchanged It would be even more fantastic, if the copy function was lazy. I think the traverse function might actually make a copy, but I would be happier with something more general (doesn't require membership in traversable), and more explicit (was actually designed for making real copies). Same thing, IORefs could help you. Anyway, I can't imagine any case where veryUnsafeAndYouShouldNeverEveryCallThisFunction_DestructiveAssign could be useful with its imperative semantics as you've described. The point is that Haskell is pure language and I use it because of this feature (not only because of this, to be exact). I don't want to use any library code that brokes pure semantics and launches nuclear bombs behind the IO monad. GHC is smart enough these days to do all optimised destructive assignments, copies and all that imperative stuff and there are plenty of other ways to get a performance boost without unsafeHorribleThings. ___ 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] Announce: EnumMap-0.0.1
For the sake of testing both options, here's a branch with the wrapper code instead of the replacement/integrated code: http://github.com/sw17ch/EnumMap/tree/wrapper On Sat, Aug 8, 2009 at 4:41 PM, Henning Thielemannlemm...@henning-thielemann.de wrote: On Sat, 8 Aug 2009, John Van Enk wrote: Hi List, I've uploaded a first version of EnumMap to hackage. EnumMap is a generalization of IntMap that constrains the key to Enum rather than forcing it to be Int. I have no idea what impact this has on performance, but it still passes all the tests that ship with IntMap. (My guess is that performance will be similar/identical unless I've missed something.) Could that be implemented as wrapper around IntMap? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announce: EnumMap-0.0.1
I've been trying to implement EnumMap as a wrapper for IntMap. Here's the first problem I ran into: IntMap.insertWithKey :: (Key - a - a - a) - Key - a - IntMap a - IntMap a I'd like to translate this to something like: EnumMap.insertWithKey :: Enum k = (Key k - a - a - a) - Key k - a - EnumMap k a - EnumMap k a My initial thought was just to make it a normal wrapper: EnumMap.insertWithKey f k v m = IntMap.insertWithKey f (unKey k) v (unEnumMap m) The obvious problem here is the type of `f' expected by the wrapper function and the internal function. Either we force the wrapper to take a function that takes an Int as the first parameter, or we rewrite the logic of insertWithKey to allow us to use the proper (Key k) type. I don't see an obvious way around this--am I missing something? On Sat, Aug 8, 2009 at 4:41 PM, Henning Thielemannlemm...@henning-thielemann.de wrote: On Sat, 8 Aug 2009, John Van Enk wrote: Hi List, I've uploaded a first version of EnumMap to hackage. EnumMap is a generalization of IntMap that constrains the key to Enum rather than forcing it to be Int. I have no idea what impact this has on performance, but it still passes all the tests that ship with IntMap. (My guess is that performance will be similar/identical unless I've missed something.) Could that be implemented as wrapper around IntMap? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announce: EnumMap-0.0.1
Allow me to answer my own question: EnumMap.insertWithKey f k v m = IntMap.insertWithKey (f . Key . toEnum) (unKey k) v (unEnumMap m) On Mon, Aug 10, 2009 at 2:32 PM, John Van Enkvane...@gmail.com wrote: I've been trying to implement EnumMap as a wrapper for IntMap. Here's the first problem I ran into: IntMap.insertWithKey :: (Key - a - a - a) - Key - a - IntMap a - IntMap a I'd like to translate this to something like: EnumMap.insertWithKey :: Enum k = (Key k - a - a - a) - Key k - a - EnumMap k a - EnumMap k a My initial thought was just to make it a normal wrapper: EnumMap.insertWithKey f k v m = IntMap.insertWithKey f (unKey k) v (unEnumMap m) The obvious problem here is the type of `f' expected by the wrapper function and the internal function. Either we force the wrapper to take a function that takes an Int as the first parameter, or we rewrite the logic of insertWithKey to allow us to use the proper (Key k) type. I don't see an obvious way around this--am I missing something? On Sat, Aug 8, 2009 at 4:41 PM, Henning Thielemannlemm...@henning-thielemann.de wrote: On Sat, 8 Aug 2009, John Van Enk wrote: Hi List, I've uploaded a first version of EnumMap to hackage. EnumMap is a generalization of IntMap that constrains the key to Enum rather than forcing it to be Int. I have no idea what impact this has on performance, but it still passes all the tests that ship with IntMap. (My guess is that performance will be similar/identical unless I've missed something.) Could that be implemented as wrapper around IntMap? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announce: EnumMap-0.0.1
http://github.com/sw17ch/EnumMap/tree/master
Perhaps you could patch what I have? :)
On Sun, Aug 9, 2009 at 12:08 AM, Thomas
DuBuissonthomas.dubuis...@gmail.com wrote:
Inflating the number of elements in the test, I see:
IntMap
inserts: 5.3 seconds
lookups: 2.0 seconds
EnumMap
inserts: 6.1 sec (15% slower)
lookups: 2.5 sec (25% slower)
EnumMap with SPECIALIZE of:
{-# SPECIALIZE join :: Prefix - EnumMap Int a - Prefix - EnumMap
Int a - EnumMap Int a #-}
{-# SPECIALIZE lookup :: Int - EnumMap Int a - Maybe a #-}
{-# SPECIALIZE lookupN :: Nat - EnumMap Int a - Maybe a #-}
{-# SPECIALIZE insert :: Int - a - EnumMap Int a - EnumMap Int a #-}
inserts: 5.3 seconds (dead on)
lookups: 2.6 seconds (owch!)
Additionally specializing the functions used in lookup{,N} doesn't
help. I tried inlining (via INLINE) a couple things but that only
made performance notably worse.
Thomas
On Sat, Aug 8, 2009 at 8:29 PM, John Van Enkvane...@gmail.com wrote:
How bad is the lookup compared to normal?
On Sat, Aug 8, 2009 at 9:02 PM, Thomas
DuBuissonthomas.dubuis...@gmail.com wrote:
On Sat, Aug 8, 2009 at 5:30 PM, Felipe Lessafelipe.le...@gmail.com wrote:
On Sat, Aug 08, 2009 at 04:14:15PM -0700, Thomas DuBuisson wrote:
There exists a small but measurable performance hit for at least one
test case (using Int as keys, obviously). Perhaps the bias would be
the other way if we were comparing EnumMap to an IntMap wrapped with
to/from Enum.
Perhaps some SPECIALIZE pragmas would help here.
Actually I tried that by adding SPECIALIZE to insert, insertN and
lookup. it seemed to make the insert benchmark competitive but not
lookup.
Thomas
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[Haskell-cafe] Announce: EnumMap-0.0.1
Hi List, I've uploaded a first version of EnumMap to hackage. EnumMap is a generalization of IntMap that constrains the key to Enum rather than forcing it to be Int. I have no idea what impact this has on performance, but it still passes all the tests that ship with IntMap. (My guess is that performance will be similar/identical unless I've missed something.) If this package competes in speed (especially with an Int key) with IntMap, I'd expect this could be merged into the containers package as an IntMap replacement. The source comments/copyright/license hasn't been changed since this is a derivative work of the original IntMap package. http://hackage.haskell.org/package/EnumMap Comments/benchmarks/criticism is appreciated. Merging this in with containers eventually would be more appreciated. :) John Van Enk ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announce: EnumMap-0.0.1
That's originally how I was thinking about doing it, but I think that requires one to re-implement all the functions available in Data.IntMap as simple wrappers that do the toEnum/fromEnum conversion. I think making it into its own module is a little cleaner. The conversion from EnumMap to IntMap is substantially cleaner than from IntMap to EnumMap: type IntMap v = EnumMap Int v /jve On Sat, Aug 8, 2009 at 4:41 PM, Henning Thielemannlemm...@henning-thielemann.de wrote: On Sat, 8 Aug 2009, John Van Enk wrote: Hi List, I've uploaded a first version of EnumMap to hackage. EnumMap is a generalization of IntMap that constrains the key to Enum rather than forcing it to be Int. I have no idea what impact this has on performance, but it still passes all the tests that ship with IntMap. (My guess is that performance will be similar/identical unless I've missed something.) Could that be implemented as wrapper around IntMap? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announce: EnumMap-0.0.1
What if we say that Enum a generalization, rather than a wrapper, of Int? If the benchmarks are even, is there a reason to use the more specific structure rather than the general one? I don't know if Enum being more complex outweighs the benefits of it being more general (if the EnumMap matches IntMap for speed). Thoughts? On Sat, Aug 8, 2009 at 6:11 PM, Henning Thielemannlemm...@henning-thielemann.de wrote: On Sat, 8 Aug 2009, John Van Enk wrote: That's originally how I was thinking about doing it, but I think that requires one to re-implement all the functions available in Data.IntMap as simple wrappers that do the toEnum/fromEnum conversion. I think making it into its own module is a little cleaner. The conversion from EnumMap to IntMap is substantially cleaner than from IntMap to EnumMap: type IntMap v = EnumMap Int v Can you implement EnumMap in terms of the Enum methods, without many conversions to Int? I mean, if you often convert to Int and back then you could achieve the same on top of IntMap. Generally I prefer the strategy from simple to complex. I consider Enum to be a wrapper around Int. http://haskell.org/haskellwiki/Simple_to_complex ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Announce: EnumMap-0.0.1
How bad is the lookup compared to normal? On Sat, Aug 8, 2009 at 9:02 PM, Thomas DuBuissonthomas.dubuis...@gmail.com wrote: On Sat, Aug 8, 2009 at 5:30 PM, Felipe Lessafelipe.le...@gmail.com wrote: On Sat, Aug 08, 2009 at 04:14:15PM -0700, Thomas DuBuisson wrote: There exists a small but measurable performance hit for at least one test case (using Int as keys, obviously). Perhaps the bias would be the other way if we were comparing EnumMap to an IntMap wrapped with to/from Enum. Perhaps some SPECIALIZE pragmas would help here. Actually I tried that by adding SPECIALIZE to insert, insertN and lookup. it seemed to make the insert benchmark competitive but not lookup. Thomas ___ 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] Haskell on a VPS
Has any one used a service similar to (or equivelant to) Slicehost or Linode to run Haskell network applications? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell on a VPS
No, I just want to know if there are any gotchas in the typical VPS setups that for some strange reason wouldn't like Haskell binaries. I couldn't think of any, but I miss details some times. Thanks. On Thu, Jul 23, 2009 at 11:08 AM, Jeremy Shawjer...@n-heptane.com wrote: At Thu, 23 Jul 2009 10:53:40 -0400, John Van Enk wrote: Has any one used a service similar to (or equivelant to) Slicehost or Linode to run Haskell network applications? I have run happstack applications on vpslink and rimuhosting VPSes. (I build everything as .debs and then just install the .debs on the server. But that has nothing to do with the fact that I am using Haskell or a VPS, it's just how I roll...) Is there some reason you think running a Haskell network application would be different than any other network application when it comes to a VPS? - jeremy ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell on a VPS
Yeah, it crossed my mind, but since my application only uses 3MB of memory in Linux, I think I'll be ok. :) On Thu, Jul 23, 2009 at 11:38 AM, Anton van Straatenan...@appsolutions.com wrote: John Van Enk wrote: No, I just want to know if there are any gotchas in the typical VPS setups that for some strange reason wouldn't like Haskell binaries. I couldn't think of any, but I miss details some times. One detail you should check is that the VPS has enough memory for the Haskell applications you intend to run. RAM tends to be the most constraining factor on cheaper VPSes, and Haskell apps aren't always the most lightweight users of RAM. (At least, mine aren't.) Anton ___ 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] Haskell on a VPS
It's a synchronization node for my VPN application written in Haskell. All it has to do is catch UDP packets, and keep a teeny tiny amount of state. I just don't have the resources to host that my self in a reliable way. On Thu, Jul 23, 2009 at 11:44 AM, Anton van Straatenan...@appsolutions.com wrote: 3MB? You're going to host Hello World on a VPS? ;) John Van Enk wrote: Yeah, it crossed my mind, but since my application only uses 3MB of memory in Linux, I think I'll be ok. :) On Thu, Jul 23, 2009 at 11:38 AM, Anton van Straatenan...@appsolutions.com wrote: John Van Enk wrote: No, I just want to know if there are any gotchas in the typical VPS setups that for some strange reason wouldn't like Haskell binaries. I couldn't think of any, but I miss details some times. One detail you should check is that the VPS has enough memory for the Haskell applications you intend to run. RAM tends to be the most constraining factor on cheaper VPSes, and Haskell apps aren't always the most lightweight users of RAM. (At least, mine aren't.) Anton ___ 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] FFI to double constants, printf
You probably want something like printf(%.10Lg,d);. Here's a shot C
example and its output:
#include stdio.h
int main(int argc, char * argv[])
{
long double d = 0.123456789;
printf(%.30Lf\n, d);
printf(%.20Lg\n, d);
printf(%.20Le\n, d);
}
/*
0.1234567887336054491370
0.123456788734
1.234567887336e-01
*/
On Fri, Jul 17, 2009 at 6:41 PM, Mauríciobriqueabra...@yahoo.com wrote:
When we printf doubles from C (like when using hsc2hs to bind to a
constant) we can get something that's not valid Haskell. See these
2 examples:
3.40282347e+38F
inf
Do you know some way to printf a double using printf (or any other
standard function) that's always going to give me valid Haskell
text, even in special cases?
Thanks,
Maurício
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Re: [Haskell-cafe] Atom resources
Are you starting a new Wiki? I'd absolutely love to have that resource. On Thu, Jul 16, 2009 at 8:14 PM, Thomas DuBuissonthomas.dubuis...@gmail.com wrote: The wiki [1] where Atom [2] once lived has been gone for some time now. The only resources I know for Atom are a couple blog posts, the haddock docs, and the Atom source on patchtag. Is anyone aware of other resources? Tom [1] http://funhdl.org/wiki/doku.php [2] http://hackage.haskell.org/package/atom ___ 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] Haskell Platform + gtk2hs
List, Has any one managed to install gtk2hs on a Windows box running the Haskell Platform? I've had no luck; it seems the gtk2hs installer is unable to find the GHC installation. /jve ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
