Re: [Haskell-cafe] What is the difference between runhaskell and compile?
Sorry for the wrong information. I made a mistake when did the test. After more testing, I think it is a bug of ghc 7.4.1. Until now, I cannot find a way to make ghc 7.4.1 compiled binary work. On Mon, May 28, 2012 at 11:01 AM, Magicloud Magiclouds magicloud.magiclo...@gmail.com wrote: Alright, with another box of different version of ghc and things. I finally got the cause. Or may I say as simple as Ozgun said, ghc 7.4.1 defaultly uses optimization. ghc-7.4.1 -O0 works. ghc-7.2.2 also works. Thank you all. On Sun, May 27, 2012 at 7:07 PM, Chris Dornan ch...@chrisdornan.com wrote: By configuration of the OpenLDAP client library I mean mostly so that SSL connections will work, but this is all system-level configuration. That GHC establishes connections in interactive mode for you indicates that the problem is not with the LDAP systems, but that something peculiar is going wrong with your GHC installation. Do you have only the one GHC installation on the system; is there any chance that ghc and ghci could be selecting different installations? Is it easy for you to try connecting with GHC-7.0.4? It would be worth a try if you can -- it might be a 7.4.1 oddity but it looks as if it could be some kind of GHC mis-installation. (If trying this with GHC-7.0.4 would be bothersome I would be interested to hear more; which O/S are you using?) Chris -Original Message- From: Magicloud Magiclouds [mailto:magicloud.magiclo...@gmail.com] Sent: 27 May 2012 10:12 To: Chris Dornan Cc: Brandon Allbery; Haskell-Cafe Subject: Re: [Haskell-cafe] What is the difference between runhaskell and compile? Hi, Sorry for the delayed reply. I am using ghc 7.4.1 and LDAP 0.6.6. When you said configuration of the OpenLDAP client library, may I have more information? Since ldap-utils and other client (php, perl, etc) do not have any problem. This might be the only clue to me. On Fri, May 25, 2012 at 4:43 PM, Chris Dornan ch...@chrisdornan.com wrote: I have been using LDAP with GHC without a problem – I get this error often but the problems have been with the configuration of the OpenLDAP client library or the OpenLDAP server. We are all taking about LDAP-0.6.6? Which version of GHC are we talking about? (I don’t think I have tested this on GHC-7.4.1, and maybe the others haven’t either.) Chris From: haskell-cafe-boun...@haskell.org [mailto:haskell-cafe-boun...@haskell.org] On Behalf Of Brandon Allbery Sent: 25 May 2012 04:21 To: Magicloud Magiclouds Cc: Haskell-Cafe Subject: Re: [Haskell-cafe] What is the difference between runhaskell and compile? On Thu, May 24, 2012 at 11:05 PM, Magicloud Magiclouds magicloud.magiclo...@gmail.com wrote: Hi there, The code could not be simpler. Just ldapInit, ldapSimpleBind. I just found that the code works with ghci, too. So to sum up, ghci/runhaskell works, ghc not. A possibility that occurs to me: does it by any chance work with ghc -threaded? Perhaps the issue relates to the different behavior of the threaded runtime (which is used automatically by ghci/runghc). -- brandon s allbery allber...@gmail.com wandering unix systems administrator (available) (412) 475-9364 vm/sms -- 竹密岂妨流水过 山高哪阻野云飞 And for G+, please use magiclouds#gmail.com. -- 竹密岂妨流水过 山高哪阻野云飞 And for G+, please use magiclouds#gmail.com. -- 竹密岂妨流水过 山高哪阻野云飞 And for G+, please use magiclouds#gmail.com. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] What is the difference between runhaskell and compile?
Sorry for the wrong information. I made a mistake when did the test. After more testing, I think it is a bug of ghc 7.4.1. Until now, I cannot find a way to make ghc 7.4.1 compiled binary work. It sounds like this should be looked at further. Somebody should verify try to repeat what you are seeing on 7.4.1. The release candidate for 7.4.2 should also be tried. (I will see if I can get time to do it myself.) Chris ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Building pattern and trying monads
observe $ flip runStateT 10 $ (put 0 mzero) | modify (+3) ((),13) If the only thing you need is backtracking, using LogicT might be a little overkill, using Maybe in the bottom of you monad stack suits just fine: case flip runStateT 10 $ (put 0 mzero) | modify (+3) of Just x - Nothing - 2012/5/27 Roman Cheplyaka r...@ro-che.info * L Corbijn aspergesoe...@gmail.com [2012-05-27 14:21:39+0200] The solution I've in mind depends on the stack being pure. When the monad stack is pure a rule can be applied, returning a maybe value (or having a MaybeT wrapper) and when returning Nothing (failed rule) reverting the stack to it's point before applying the rule. As I'm not quite sure about the design (nor good at software design) I've some questions about this approach. 1. Is there a better approach then using a state monad for building the 'products'? If you need to interleave building your products and analyzing them, State seems a reasonable choice here. 2. My solution with saving/reverting monad-stacks seems quite a hassle/hack, so is it a good approach or is there something better? You can use a backtracking monad here ([] or Logic). The key thing is to put the backtracking monad in the bottom of your stack (everything above it will be restored on mzero). On the other hand, if you want some global effects that should not be restored, you can put corresponding monads below LogicT in the stack. Example: observe $ flip runStateT 10 $ (put 0 mzero) | modify (+3) ((),13) Note that put 0 had no effect here, because it was followed by mzero. -- Roman I. Cheplyaka :: http://ro-che.info/ ___ 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 the difference between runhaskell and compile?
Sorry for the wrong information. I made a mistake when did the test. After more testing, I think it is a bug of ghc 7.4.1. Until now, I cannot find a way to make ghc 7.4.1 compiled binary work. I have set up this test on 7.4.1 and I cannot recreate the problem -- compiling and running an equivalent program (the posted program with local domain, bindDN and bindPW definitions localised and all other let bindings removed) leads to a successful server connection when passed the right password but fails to connect with the wrong password. This was the behaviour you were seeing yourself with 7.2.2 was it not? I can only recommend re-installing 7.4.1 and trying again. Chris ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Building pattern and trying monads
* Yves Parès yves.pa...@gmail.com [2012-05-28 11:28:22+0200] observe $ flip runStateT 10 $ (put 0 mzero) | modify (+3) ((),13) If the only thing you need is backtracking, using LogicT might be a little overkill, using Maybe in the bottom of you monad stack suits just fine: case flip runStateT 10 $ (put 0 mzero) | modify (+3) of Just x - Nothing - Indeed, I didn't realise that Maybe may be (no pun intended) sufficient here! -- Roman I. Cheplyaka :: http://ro-che.info/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Building pattern and trying monads
Actually, I think the backtracking property here stems more from the MonadPlus StateT instance than from the properties of Maybe. (mplus a b runs a and b by passing explicitely the same state to them). 2012/5/28 Roman Cheplyaka r...@ro-che.info * Yves Parès yves.pa...@gmail.com [2012-05-28 11:28:22+0200] observe $ flip runStateT 10 $ (put 0 mzero) | modify (+3) ((),13) If the only thing you need is backtracking, using LogicT might be a little overkill, using Maybe in the bottom of you monad stack suits just fine: case flip runStateT 10 $ (put 0 mzero) | modify (+3) of Just x - Nothing - Indeed, I didn't realise that Maybe may be (no pun intended) sufficient here! -- Roman I. Cheplyaka :: http://ro-che.info/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Estágio com Haskell em SP (Haskell internship at São Paulo, Brazil)
(English message follows after the break.) Olá! Estamos procurando um estagiário para trabalhar conosco em São Paulo capital. Nós somos uma startup apaixonada por Haskell com uma boa participação na comunidade e grandes projetos e desafios! Se você está interessado, basta me mandar um e-mail (felipe.le...@gmail.com) com um link para sua conta do GitHub (ou para projetos em que você já tenha trabalhado). Você não precisa ser experiente em Haskell nem ter nenhum código Haskell publicado, mas isso seria um diferencial =). Como a startup está em stealth mode, não posso divulgar o nome da empresa e por isso estou usando meu e-mail pessoal. Até mais! === Hey! We're looking for an intern to work with us in São Paulo, Brazil. We're a startup passionate about using Haskell with great projects and challenges! If you're interested, just send me an e-mail (felipe.le...@gmail.com) with a link to your GitHub account (or to any projects you've worked at). You don't need to be an experienced Haskeller nor have any published Haskell code, but that would be a plus =). As the startup is in stealth mode, I can't disclose the company's name nor use my work e-mail (that's why I'm using my personal one). Cheers, -- Felipe. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Fundeps and overlapping instances
Gábor Lehel illissius at gmail.com writes: If you're referring to the NewAxioms work Simon linked to ... [snip] ... It seems vaguely similar to a paper on instance chains[2] I saw once. Thanks Gábor for the reference, but I don't think they're very comparable. The instance chains is in context of fundeps and overlaps (as you'd expect from MPJ, since it was him who first introduced fundeps). I know fundeps are 'theoretically' equivalent to type families. But I think the instance chains paper is a good demonstration of why I find fundeps so awkward to follow at the superficial syntax level for type-level programming: - you have to look first to the end of the instance to find the head; - and assume (hope!) that the 'result' is the rightmost typevar; - then backtrack through the list of constraints; - some are only validation limits on the instance; - some are calculating intermediate results (again with their result at right). Instance chains include: - not only resolving overlaps (yes, that's similar to NewAxioms); - but also choosing instances based on type class membership; (often asked for by newbies, but really difficult to implement) - and explicit failure leading to backtracking search (Explicit failure is missing from NewAxioms. I don't mean backtracking, but at least treating certain conditions as no instance match. Oleg's HList work needs that (for example in the Lacks constraint), but has to fudge it by putting a fake instance with a fake constraint.) Does the overall instance chain structure guarantee termination of type inference? I don't follow the algebra enough to be sure. Morris Jones' examples seem to me contrived: they've set up overlapping instances where you could avoid them, and even where they seem harder to follow. Yes, their solution is simpler than the problem they start with; but no, the problem didn't need to be that complex in the first case. (I'm looking especially at the GCD/Subt/Lte example -- I think I could get that to work in Hugs with fundeps and no overlaps.) I'm surprised there isn't a Monad Transformer example: [3] by MPJ uses overlaps for MonadT. And MonadT was (I thought) what gave all the trouble with overlaps and default instances and silently changing behaviour. (There's a brief example in Morris' supporting survey - ref [11] in [2].) Anybody out there can explain further? AntC [2] http://citeseerx.ist.psu.edu/viewdoc/download? doi=10.1.1.170.9113rep=rep1type=pdf [3] Functional Programming with Overloading and Higher-Order Polymorphism Mark P. Jones, 1995 ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] What is the difference between runhaskell and compile?
Interesting. I have this code tested in Debian unstable/stable, CentOS 6.1, all 64 bit, with two different version of libldap2. At first, Debian-s were installed with 7.4.1, CentOS with 7.2.2. Only in CentOS the code connected after compiled. Then I removed 7.4.1 from Debian stable and installed 7.2.2. The code worked. At last, I installed 7.4.1 in CentOS. The code did not work. Could you send the .hi/.o to me, so maybe I could find out the different? Also the exact original source. Thank you. On Mon, May 28, 2012 at 6:27 PM, Chris Dornan ch...@chrisdornan.com wrote: Sorry for the wrong information. I made a mistake when did the test. After more testing, I think it is a bug of ghc 7.4.1. Until now, I cannot find a way to make ghc 7.4.1 compiled binary work. I have set up this test on 7.4.1 and I cannot recreate the problem -- compiling and running an equivalent program (the posted program with local domain, bindDN and bindPW definitions localised and all other let bindings removed) leads to a successful server connection when passed the right password but fails to connect with the wrong password. This was the behaviour you were seeing yourself with 7.2.2 was it not? I can only recommend re-installing 7.4.1 and trying again. Chris -- 竹密岂妨流水过 山高哪阻野云飞 And for G+, please use magiclouds#gmail.com. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
