Re: [Haskell-cafe] GPL License of H-Matrix and prelude numeric
Chris Smith cdsm...@gmail.com writes: I disagree, I've always interpreted the license to cover the text in that particular package. There seems to be a difference in focus here that's confusing to me. When I write a library, my primary concern is generally with helping others use that library I'm not saying it's a bad idea to echo the licensing of dependencies, say for a library that wraps an underlying C-library. But there could be valid reasons for not doing it. As a result, if I were to write a package that depends on someone else's GPLed library, I don't see it being anywhere near worth the conceptual weight to apply a different license to the source code in the current package; since ultimately, the terms of the GPL are going to apply to anyone who builds a program with the library anyway. What if the library depends on proprietary code? Maybe you want to make the code available for educational purposes, or porting to non-proprietary alternatives? What if you write a database access library which links against various backends - just because one of the backends has restriction (GPL, say), you may want to use a liberal license so that people can still use it in their proprietary project with (say) BSD-licensed back ends. At any rate we need a different way to deal with this, since the license for the resulting binary can vary depending on build flags, different binaries from the same package can end up having different licensing, The other (somewhat obvious, in my mind) possibility is to consider this a poor use of build flags Well, I disagree - it's nice to be able to ./configure --without-readline (or whatever) precisely to avoid licensing conditions that are unacceptable to your project. The alternative is more duplication of code. I suppose this is another reason to specify upper bounds on dependencies. :) In this case, it's a matter of legal compatibility rather than technical compatibility, but it amounts to the same thing. For most of us, technical compatibility is what's relevant, since we typically download from Hackage and build everything from scratch, we don't often redistribute binaries. Linux distributions will have to audit packages a bit more carefully. That certainly seems like overkill. First of all, as mentioned above, it's confusing and unnecessary to package things in such a way that different licenses will apply to different pieces or build options. We have lots of itty bitty packages with a variety of licenses, so I'm not sure this is so easy for non-trivial projects. Furthermore, the example above could be greatly shortened by just saying GPL. I'd be wary of automatically interpreting licensing issues for users. Better to just provide the information, and let them decide whether they have redistribution rights or not. -k -- 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
Re: [Haskell-cafe] Problem about exception
It seems that the problem is to follow a protocol, reporting protocol errors (unexpected responses) and permitting recovery if the `supervisor' decided that the error can be fixed by re-reading from the server. This problem -- specifically, communicating with a supervisor `out-of-band' and recovery -- is a good use case for delimited continuations. The following code implements the scenario in Magicloud's message. http://okmij.org/ftp/continuations/CCmonad/ProtocolRecovery.hs Actually, the code is interactive, letting the use play a good or a bad server. One can see for themselves the effect of expected or unexpected responses. The title comments show the examples of good or bad interactions. Here is a sample transcript of several interactions. ProtocolRecovery main Client Connected sending: Req_hello Enter response, as a number 1..4 1 sending: Req_who_are_you Enter response, as a number 1..4 2 Client Dis-connected ProtocolRecovery main Client Connected sending: Req_hello Enter response, as a number 1..4 1 sending: Req_who_are_you Enter response, as a number 1..4 3 Exception: Err_bad_resp Res_debug DEBUG Enter response, as a number 1..4 3 Exception: Err_bad_resp Res_debug DEBUG Enter response, as a number 1..4 2 Client Dis-connected *ProtocolRecovery main Client Connected sending: Req_hello Enter response, as a number 1..4 1 sending: Req_who_are_you Enter response, as a number 1..4 4 Exception: Err_bad_resp Res_disconnect Aborting Client Dis-connected *ProtocolRecovery main Client Connected sending: Req_hello Enter response, as a number 1..4 1 sending: Req_who_are_you Enter response, as a number 1..4 1 Exception: Err_bad_resp Res_hello Really bad response! Client Dis-connected ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Problem about exception
Thank you. I am looking into it. On Thu, Jan 27, 2011 at 5:05 PM, o...@okmij.org wrote: It seems that the problem is to follow a protocol, reporting protocol errors (unexpected responses) and permitting recovery if the `supervisor' decided that the error can be fixed by re-reading from the server. This problem -- specifically, communicating with a supervisor `out-of-band' and recovery -- is a good use case for delimited continuations. The following code implements the scenario in Magicloud's message. http://okmij.org/ftp/continuations/CCmonad/ProtocolRecovery.hs Actually, the code is interactive, letting the use play a good or a bad server. One can see for themselves the effect of expected or unexpected responses. The title comments show the examples of good or bad interactions. Here is a sample transcript of several interactions. ProtocolRecovery main Client Connected sending: Req_hello Enter response, as a number 1..4 1 sending: Req_who_are_you Enter response, as a number 1..4 2 Client Dis-connected ProtocolRecovery main Client Connected sending: Req_hello Enter response, as a number 1..4 1 sending: Req_who_are_you Enter response, as a number 1..4 3 Exception: Err_bad_resp Res_debug DEBUG Enter response, as a number 1..4 3 Exception: Err_bad_resp Res_debug DEBUG Enter response, as a number 1..4 2 Client Dis-connected *ProtocolRecovery main Client Connected sending: Req_hello Enter response, as a number 1..4 1 sending: Req_who_are_you Enter response, as a number 1..4 4 Exception: Err_bad_resp Res_disconnect Aborting Client Dis-connected *ProtocolRecovery main Client Connected sending: Req_hello Enter response, as a number 1..4 1 sending: Req_who_are_you Enter response, as a number 1..4 1 Exception: Err_bad_resp Res_hello Really bad response! Client Dis-connected -- 竹密岂妨流水过 山高哪阻野云飞 ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Haskell for children? Any experience?
So I find myself being asked to plan Haskell programming classes for one hour, once a week, from September through May this coming school year. The students will be ages 11 to 13. I'm wondering if anyone has experience in anything similar that they might share with me. I'm trying to decide if this is feasible, or it I should try to do something different. To be honest, as much as I love Haskell, I tried to push the idea of learning a different language; perhaps Python. So far, the kids will have none of it! This year, I've been teaching a once-a-week exploratory mathematics sort of thing, and we've made heavy use of GHCi... and they now insist on learning Haskell. (By the way, GHCi is truly amazing for exploratory mathematics. We really ought to promote the idea of Haskell for elementary / junior-high level math teachers! It's so easy to just try stuff; and there are so many patterns you can just discover and then say Huh, why do you think that happens? Can you write it down precisely? ...) -- Chris Smith ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell for children? Any experience?
Ye gods! A B D [1] language for kids? At least give them a fighting chance [2] at becoming future developers. Haskell's immutability is good for mathematics but doing anything else takes a great deal of up-front patience and perseverance, two very rare qualities in that demographic if my own childhood is any indication. BTW I want to be wrong so if you do succeed with this I will feast on crow with gusto. -deech [1] http://c2.com/cgi/wiki?BondageAndDisciplineLanguage [2] http://scratch.mit.edu/ On Thu, Jan 27, 2011 at 9:04 AM, Chris Smith cdsm...@gmail.com wrote: So I find myself being asked to plan Haskell programming classes for one hour, once a week, from September through May this coming school year. The students will be ages 11 to 13. I'm wondering if anyone has experience in anything similar that they might share with me. I'm trying to decide if this is feasible, or it I should try to do something different. To be honest, as much as I love Haskell, I tried to push the idea of learning a different language; perhaps Python. So far, the kids will have none of it! This year, I've been teaching a once-a-week exploratory mathematics sort of thing, and we've made heavy use of GHCi... and they now insist on learning Haskell. (By the way, GHCi is truly amazing for exploratory mathematics. We really ought to promote the idea of Haskell for elementary / junior-high level math teachers! It's so easy to just try stuff; and there are so many patterns you can just discover and then say Huh, why do you think that happens? Can you write it down precisely? ...) -- Chris Smith ___ 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 for children? Any experience?
Hi, I'm also curious about this. Is a pure programming style like Haskell's less or more natural than an imperative mutable-state based one to kids without experience. I intuitively expect that for kids with a high-school background in mathematics would find the first more natural, but this is not based on any teaching experience. Does anyone have real-life experience with this or know of any related literature? Thanks Dominique 2011/1/27 Vo Minh Thu not...@gmail.com: Hi, You said Haskell's immutability is good for mathematics but doing anything else takes a great deal of up-front patience and perseverance[...] I guess it is true for imperative programmers... but are you saying that about kids that just know how to use a calculator? Cheers, Thu 2011/1/27 aditya siram aditya.si...@gmail.com: Ye gods! A B D [1] language for kids? At least give them a fighting chance [2] at becoming future developers. Haskell's immutability is good for mathematics but doing anything else takes a great deal of up-front patience and perseverance, two very rare qualities in that demographic if my own childhood is any indication. BTW I want to be wrong so if you do succeed with this I will feast on crow with gusto. -deech [1] http://c2.com/cgi/wiki?BondageAndDisciplineLanguage [2] http://scratch.mit.edu/ On Thu, Jan 27, 2011 at 9:04 AM, Chris Smith cdsm...@gmail.com wrote: So I find myself being asked to plan Haskell programming classes for one hour, once a week, from September through May this coming school year. The students will be ages 11 to 13. I'm wondering if anyone has experience in anything similar that they might share with me. I'm trying to decide if this is feasible, or it I should try to do something different. To be honest, as much as I love Haskell, I tried to push the idea of learning a different language; perhaps Python. So far, the kids will have none of it! This year, I've been teaching a once-a-week exploratory mathematics sort of thing, and we've made heavy use of GHCi... and they now insist on learning Haskell. (By the way, GHCi is truly amazing for exploratory mathematics. We really ought to promote the idea of Haskell for elementary / junior-high level math teachers! It's so easy to just try stuff; and there are so many patterns you can just discover and then say Huh, why do you think that happens? Can you write it down precisely? ...) -- Chris Smith ___ 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 ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell for children? Any experience?
On Thu, 2011-01-27 at 15:26 +, Stephen Tetley wrote: John Peterson had some nice work using Haskore and Fran for elementary teaching on the old Haskell.org website. Google's cache says the old URL was here but its now vanished: www.haskell.org/edsl/campy/campy-2003-music.ppt That sounds great! If you do have an existing copy of the slides, I'd like to see them. Especially the idea of using music for programming with a nice embedded DSL / combinator library would be amazing. -- Chris ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell for children? Any experience?
On Thu, 27 Jan 2011 16:26:01 +0100, Stephen Tetley stephen.tet...@gmail.com wrote: On 27 January 2011 15:04, Chris Smith cdsm...@gmail.com wrote: [SNIP] I'm wondering if anyone has experience in anything similar that they might share with me. I'm trying to decide if this is feasible, or it I should try to do something different. Hi Chris John Peterson had some nice work using Haskore and Fran for elementary teaching on the old Haskell.org website. Google's cache says the old URL was here but its now vanished: www.haskell.org/edsl/campy/campy-2003-music.ppt I've copies of the slides somewhere but the landing page had extra notes and examples. I can send you the slides off-list if you want them. The old server is still up till the end of this month (four days to go!); the URL of the landing page is: http://oldhaskell.cs.yale.edu/edsl/ Regards, Henk-Jan van Tuyl -- http://Van.Tuyl.eu/ http://members.chello.nl/hjgtuyl/tourdemonad.html -- ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell for children? Any experience?
Ye gods! A B D [1] language for kids? At least give them a fighting chance [2] at becoming future developers. Haskell's immutability is good for mathematics but doing anything else takes a great deal of up-front patience and perseverance, two very rare qualities in that demographic if my own childhood is any indication. Begone, disbeliever! And listen to the gospel of Matthias Felleisen preaching the truth: http://vimeo.com/6631514 (presentation from ICFP 2009) The paper is A Functional I/O System - or, Fun for Freshman Kids: http://www.ccs.neu.edu/scheme/pubs/icfp09-fffk.pdf Alas, it's about Scheme, but I am sure it would be both interesting and useful regardless. Cheers, /Niklas ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Building a shared library with FFI on x86_64
I have a project that involves building a shared library containing code generated by GHC and exposed using the foreign function interface to other C programs that link against it. I'm able to build a functioning library without issue on 32bit x86 systems using GHC 6.8.2 and 6.12.3. When I try to build on a 64bit x86 system I get a relocation error that advises I include -fPIC. Including -fPIC does not help though. I'm wondering if I'm either doing something wrong or if this could be a problem with GHC. I've created and attached a small example that illustrates this issue. When building on 64bit x86 with GHC 7.0.1 and -fPIC and -dynamic I get the following error. (Similar with GHC 6.12.3) /usr/bin/ld: CLibrary.o: relocation R_X86_64_PC32 against `CLibrary_testFunctionCWrapper_srt' can not be used when making a shared object; recompile with -fPIC /usr/bin/ld: final link failed: Bad value When building on 64bit x86 with GHC 7.0.1 and -fPIC and without -dynamic I get the following error (Similar with GHC 6.12.3 and 6.8.2) /usr/bin/ld: /home/CIRG/ew/local/lib/ghc-7.0.1/base-4.3.0.0/libHSbase-4.3.0.0.a(Base__1.o): relocation R_X86_64_32S against `a local symbol' can not be used when making a shared object; recompile with -fPIC /home/CIRG/ew/local/lib/ghc-7.0.1/base-4.3.0.0/libHSbase-4.3.0.0.a: could not read symbols: Bad value When building on 32bit x86 with GHC 6.12.3 I get no error regardless of -fPIC or -dynamic. When building on 32bit x86 with GHC 6.8.2 I get no error regardless of -fPIC and without -dynamic. Any advice would be appreciated! Thanks. module CLibrary where import Foreign.C.Types import Foreign.C.String import Foreign.Marshal.Alloc import Foreign.Marshal.Array import Foreign.Ptr import Foreign.Storable foreign export ccall testFunction testFunctionCWrapper :: CString - IO (Ptr CString) testFunctionCWrapper :: CString - IO (Ptr CString) testFunctionCWrapper cs = do input - peekCString cs output1 - newCString hello world output2 - newCString input newArray [output1, output2] LIB=test.so OPTIONS=-fPIC -XForeignFunctionInterface -no-hs-main -optl -shared -rdynamic #OPTIONS=-dynamic -fPIC -XForeignFunctionInterface -no-hs-main -optl -shared -rdynamic GHC=ghc #GHC=/home/CIRG/ew/local/bin/ghc all: $(GHC) $(OPTIONS) --make CLibrary -o $(LIB) clean: rm -rf *.hi *.o CLibrary_stub.c CLibrary_stub.h pretty: clean rm -rf *~ $(LIB) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Call for Copy: Monad.Reader Issue 18
Whether you're an established academic or have only just started learning Haskell, if you have something to say, please consider writing an article for The Monad.Reader! The submission deadline for Issue 18 will be: **Friday, April 1, 2011** This will be a normal issue -- but don't forget to also submit your Haskell poems and short stories by February 18 for inclusion in the special poetry and fiction edition [1]! The Monad.Reader The Monad.Reader is a electronic magazine about all things Haskell. It is less formal than journal, but somehow more enduring than a wiki-page. There have been a wide variety of articles: exciting code fragments, intriguing puzzles, book reviews, tutorials, and even half-baked research ideas. Submission Details ~~ Get in touch with me if you intend to submit something -- the sooner you let me know what you're up to, the better. Please submit articles for the next issue to me by e-mail (byorgey at cis.upenn.edu). Articles should be written according to the guidelines available from http://themonadreader.wordpress.com/contributing/ Please submit your article in PDF, together with any source files you used. The sources will be released together with the magazine under a BSD license. If you would like to submit an article, but have trouble with LaTeX please let me know and we'll work something out. [1] http://themonadreader.wordpress.com/2011/01/19/call-for-copy-special-poetry-and-fiction-edition/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Building a shared library with FFI on x86_64
Thanks to http://www.well-typed.com/blog/30 I was able to figure out what I was doing wrong. Replacing -optl -shared with just -shared and using -dynamic allows linking to complete. :D On 2011-01-27 11:59 AM, Eric Webster wrote: I have a project that involves building a shared library containing code generated by GHC and exposed using the foreign function interface to other C programs that link against it. I'm able to build a functioning library without issue on 32bit x86 systems using GHC 6.8.2 and 6.12.3. When I try to build on a 64bit x86 system I get a relocation error that advises I include -fPIC. Including -fPIC does not help though. I'm wondering if I'm either doing something wrong or if this could be a problem with GHC. I've created and attached a small example that illustrates this issue. When building on 64bit x86 with GHC 7.0.1 and -fPIC and -dynamic I get the following error. (Similar with GHC 6.12.3) /usr/bin/ld: CLibrary.o: relocation R_X86_64_PC32 against `CLibrary_testFunctionCWrapper_srt' can not be used when making a shared object; recompile with -fPIC /usr/bin/ld: final link failed: Bad value When building on 64bit x86 with GHC 7.0.1 and -fPIC and without -dynamic I get the following error (Similar with GHC 6.12.3 and 6.8.2) /usr/bin/ld: /home/CIRG/ew/local/lib/ghc-7.0.1/base-4.3.0.0/libHSbase-4.3.0.0.a(Base__1.o): relocation R_X86_64_32S against `a local symbol' can not be used when making a shared object; recompile with -fPIC /home/CIRG/ew/local/lib/ghc-7.0.1/base-4.3.0.0/libHSbase-4.3.0.0.a: could not read symbols: Bad value When building on 32bit x86 with GHC 6.12.3 I get no error regardless of -fPIC or -dynamic. When building on 32bit x86 with GHC 6.8.2 I get no error regardless of -fPIC and without -dynamic. Any advice would be appreciated! Thanks. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] A few days to go before the old server goes down
L.S., Only four days until the old Haskell.org server disappears; I found the following missing: http://www.haskell.org/yale/ http://darcs.haskell.org/hfuse/ http://haskell.org/gtk2hs/ http://haskell.org/FranTk http://www.haskell.org/yampa/ http://www.haskell.org/visualhaskell/ http://haskell.org/~kolmodin http://haskell.org/graphics/ http://www.haskell.org/libraries/ http://haskell.org/hdirect/ http://haskell.org/haskore/ http://darcs.haskell.org/wxhaskell/ http://www.haskell.org/all_about_monads http://www.haskell.org/edsl/ http://www.haskell.org/jcp/ http://darcs.haskell.org/yaht http://cvs.haskell.org/darcs/ http://haskell.org/ObjectIO http://www.haskell.org/sitewiki/ http://darcs.haskell.org/~lemmih/ It would also be a shame if useful information would be lost, so copy the pages before it is too late! (The Wayback Machine has no recent copies, or even none at all for some pages.) If they have moved, it would be useful to know whereto, as several HaskellWiki pages have to be updated. Regards, Henk-Jan van Tuyl -- http://Van.Tuyl.eu/ http://members.chello.nl/hjgtuyl/tourdemonad.html -- ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell for children? Any experience?
On Thu, 2011-01-27 at 16:40 +0100, klondike wrote: Two days ago I was referred to this project: http://wizbang.sourceforge.net/WizBang/WizBang.html The language is quite imperative but to me looks as a child friendly programming language due to its low complexity. Thanks for this and other related suggestions. Really, though, I'm not looking to find a new language; and almost surely not one like WizBang. I do want to keep things light, interesting, and fun... a DSL inside of Haskell might be interesting. But the absolute last message I want to send is that I don't think they are ready for a real language. Not after they've already played with Haskell and GHCi for mathematics! -- Chris Smith ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] tricky recursive type instance method
On Thu, Jan 27, 2011 at 9:35 PM, Frank Kuehnel vince...@mac.com wrote: Hi folks, how do I make this work: I want a division algebra over a field k, and I want to define the conjugation of complex numbers, i.e. conj (C 1 2) but also the conjugation of tensors of complex numbers conj (C (C 1 2) (C 1 4)) ghci load that stuff butt barfs on a simple conj (C 1 2) with instance Real a = DAlgebra a a -- Defined at Clifford.hs:20:10-31 instance (Real r, Num a, DAlgebra a r) = DAlgebra (Complex a) r here's the code: -- for a normed division algebra we need a norm and conjugation! class DAlgebra a k | a - k where -- need functional dependence because conj doesn't refer to k conj :: a - a abs2 :: a - k -- real numbers are a division algebra instance Real a = DAlgebra a a where conj = id abs2 x = x*x -- Complex numbers form a normed commutative division algebra data Complex a = C a a deriving (Eq,Show) instance Num a = Num (Complex a) where fromInteger a = C (fromInteger a) 0 (C a b)+(C a' b') = C (a+a') (b+b') (C a b)-(C a' b') = C (a-a') (b-b') (C a b)*(C a' b') = C (a*a'-b*b') (a*b'+b*a') instance (Real r, Num a, DAlgebra a r) = DAlgebra (Complex a) r where conj (C a b) = C a (conj (-b)) abs2 (C a b) = (abs2 a) + (abs2 b) What error are you getting in GHCi? It wasn't immediately clear from your email, but maybe I missed it. It looks like you have overlapping instances between `DAlgebra a a` and `DAlgebra (Complex a) r`, so if that's what you want you'll need to making sure you have the OverlappingInstances extension turned on. You might run in to other issues further on. Antoine Thanks for you help! ___ 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 for children? Any experience?
On Thu, 2011-01-27 at 09:28 -0600, aditya siram wrote: Ye gods! A B D [1] language for kids? I do share those concerns. Like I said in the original post, my initial reaction was to push for something like Python. But the kids are very clear; if I'm at all willing, they want to learn Haskell! And honestly, I'd like to try it too, *if* I can do my due diligence research, and pay attention to others who might have tried and learned some lessons along the way! At least give them a fighting chance [2] at becoming future developers. [2] http://scratch.mit.edu/ Thanks for that suggestion; unfortunately, much like the WizBang suggestion, Scratch is going to come across as if, for some reason, after happily using GHCi for math, I now don't trust them with a real programming language. I can guarantee you they won't be interested in programming by dragging around brightly colored things that look like puzzle pieces on the screen; and I can't imagine keeping it up for the whole year even if they were interested. -- Chris ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Cabal proxy configuration
Please explain this a bit. Where are the configuration files for cabal install.
I tried to enter the line in the terminal and it apparently it accepted i.e
gave no error but then running cabal update results in this error
No action for prompting/generating user+password credentials provided (use:
setAuthorityGen); returning Nothing
cabal: Failed to download index 'ErrorMisc Unsucessful HTTP code: (4,0,7)'
This is the first time I am using cabal so I am almost completely blank for it.
Thanks
Azeem
Date: Fri, 28 Jan 2011 15:26:08 +1000
Subject: Re: [Haskell-cafe] Cabal proxy configuration
From: ivan.miljeno...@gmail.com
To: aze...@live.com
CC: haskell-cafe@haskell.org
On 28 January 2011 15:13, Azeem -ul-Hasan aze...@live.com wrote:
My university requires the students to use internet through an authenticated
http proxy. How do I configure cabal for that? I am using Ubuntu. Please be
detailed about it.
Do you mean Cabal or cabal-install?
Assuming the latter:
export http_proxy=http://${username}:${password}@${proxy_address}
--
Ivan Lazar Miljenovic
ivan.miljeno...@gmail.com
IvanMiljenovic.wordpress.com
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Re: [Haskell-cafe] Cabal proxy configuration
On 28 January 2011 16:00, Azeem -ul-Hasan aze...@live.com wrote: Please explain this a bit. Where are the configuration files for cabal install. cabal-install is configured in ~/.cabal/config However, as far as I'm aware it uses normal http connections and doesn't require any particular configuration for proxies: it just uses the system settings. For example: http://serverfault.com/questions/132640/ubuntu-set-system-proxy-from-command-line -- Ivan Lazar Miljenovic ivan.miljeno...@gmail.com IvanMiljenovic.wordpress.com ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
