Re: [Haskell-cafe] GPL answers from the SFLC (WAS: Re: ANN: hakyll-0.1)
On Thu, Mar 4, 2010 at 18:05, Stephen Tetley stephen.tet...@gmail.com wrote: Hi Tom Hmm, its seems I'm due to eat my hat... To me though, the judgement makes that insistence that using an API is making a derivative work. I can't see how that squares up. That has, AFAIU, been the intention of the GPL all along. See e.g. http://www.fsf.org/licensing/licenses/why-not-lgpl.html It also explains why there has been a discussion in the Linux kernel community about closed source drivers (e.g. nvidia). The LGPL was, AFAIU, written to explicitly allow a shift of license at the API level. Without the insistence you point out, GPL and LGPL would be pretty much the same license. /M -- Magnus Therning(OpenPGP: 0xAB4DFBA4) magnus＠therning．org Jabber: magnus＠therning．org http://therning.org/magnus identi.ca|twitter: magthe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GPL answers from the SFLC (WAS: Re: ANN: hakyll-0.1)
On Fri, Mar 5, 2010 at 12:53 AM, Kevin Jardine kevinjard...@yahoo.com wrote: I'm a Haskell newbie but long time open source developer and I've been following this thread with some interest. The GPL is not just a license - it is a form of social engineering and social contract. The idea if I use the GPL is that I am releasing free and open source software to the community. You are welcome to use it for any purpose but in exchange you must also agree to release any software you create that uses my software as free and open source. That is the difference between GPL and BSD type licenses. The GPL very deliberately creates an obligation. Yes, that can be inconvenient. It is meant to be inconvenient. Actually the GPL reminds me of a Haskell concept that I am struggling with right now - the monad. When I started writing Haskell code I was always trying to mix pure and IO code and I soon learned that once I used the IO monad I was stuck within it. The monad creates an inconvenient obligation and any IO code can only be used within other IO code. There are good reasons for monads (just as, in my view, there are good reasons for the GPL) but using them means that I need to make a lot of changes to the way I write software. Sure. You can put a GPL license on any software: license :: a - GPL a And if you could have used some public domain package 'a' to create some GPL'd software, then you can use the GPL'd 'a' to create that same software. usage :: (a - GPL b) - GPL a - GPL b :-P Luke ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GPL answers from the SFLC (WAS: Re: ANN: hakyll-0.1)
2010/3/5 Magnus Therning mag...@therning.org: On Thu, Mar 4, 2010 at 18:05, Stephen Tetley stephen.tet...@gmail.com wrote: Hi Tom Hmm, its seems I'm due to eat my hat... To me though, the judgement makes that insistence that using an API is making a derivative work. I can't see how that squares up. That has, AFAIU, been the intention of the GPL all along. See e.g. http://www.fsf.org/licensing/licenses/why-not-lgpl.html It also explains why there has been a discussion in the Linux kernel community about closed source drivers (e.g. nvidia). The LGPL was, AFAIU, written to explicitly allow a shift of license at the API level. Without the insistence you point out, GPL and LGPL would be pretty much the same license. I don't see how what you say is related by the link you provide. They say there is an advantage to make a library GPL when there is no alternative so program using the library is required to be GPL too. As an example, they licensed the C library LGPL because they were already other available C library, so making their one GPL licensed could not really drive more programs to be GPL. Indeed the boundary of a library is its API but that hardly translates to say that the GPL covers the API. Cheers, Thu ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GPL answers from the SFLC (WAS: Re: ANN: hakyll-0.1)
On Fri, Mar 5, 2010 at 08:55, minh thu not...@gmail.com wrote: 2010/3/5 Magnus Therning mag...@therning.org: On Thu, Mar 4, 2010 at 18:05, Stephen Tetley stephen.tet...@gmail.com wrote: Hi Tom Hmm, its seems I'm due to eat my hat... To me though, the judgement makes that insistence that using an API is making a derivative work. I can't see how that squares up. That has, AFAIU, been the intention of the GPL all along. See e.g. http://www.fsf.org/licensing/licenses/why-not-lgpl.html It also explains why there has been a discussion in the Linux kernel community about closed source drivers (e.g. nvidia). The LGPL was, AFAIU, written to explicitly allow a shift of license at the API level. Without the insistence you point out, GPL and LGPL would be pretty much the same license. I don't see how what you say is related by the link you provide. They say there is an advantage to make a library GPL when there is no alternative so program using the library is required to be GPL too. As an example, they licensed the C library LGPL because they were already other available C library, so making their one GPL licensed could not really drive more programs to be GPL. Indeed the boundary of a library is its API but that hardly translates to say that the GPL covers the API. Ah, I might have misunderstood the whole thread then. I thought the discussion was about using the API of a GPLd library. While your comment suggests it's actually about re-implementing a GPLd library, making it API compatible, and releasing the re-implementation under another license. In that case wouldn't a project like Harmony (http://en.wikipedia.org/wiki/Harmony_toolkit) be problematic? So would editline's mode for compatibility with readline, right? (GNU TLS would probably not get in trouble for providing an OpenSSL compatibility layer though.) /M -- Magnus Therning(OpenPGP: 0xAB4DFBA4) magnus＠therning．org Jabber: magnus＠therning．org http://therning.org/magnus identi.ca|twitter: magthe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: How do you rewrite your code?
Ertugrul Soeylemez schrieb: As a side note: I have found that many people don't understand the filterM-based solution. That's because many people don't understand the list monad and the power of the monadic interface. So if you work in a group, either don't write code like this or preferably explain monads to your groupmates. Alternatively, keep all versions and compare them in a QuickCheck test-suite. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GPL answers from the SFLC (WAS: Re: ANN: hakyll-0.1)
Hi Magnus The 'Why not LGPL' doesn't cover the particular argument here: using the ordinary GPL for a library makes it available only for free programs. The particular concern we have here is quite specific, considering (--) to be a dependency, can Hackage libraries under BSD3 that depend on libraries under GPL? [1] App -- libBSD3 -- libGPL Any App built has to incorporate the GPL library - so the App has to be GPL. -- No dispute --. Similar BSD3 is a GPL compatible library, so this dependency chain would be legal: [2] App -- libGPL -- libBSD The argument is whether it is legal to distribute (read host on Hackage) BSD3 libs that depend on GPL libs - formulation [1]. -- I'd have thought Harmony would be problematic for different reasons - i.e. coping the API of a copyright work. Best wishes Stephen ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GPL answers from the SFLC (WAS: Re: ANN: hakyll-0.1)
On 5 March 2010 09:38, Stephen Tetley stephen.tet...@gmail.com wrote: Similar BSD3 is a GPL compatible library, so this dependency chain would be legal: [2] App -- libGPL -- libBSD Typo above - should be Similar BSD3 is a GPL compatible __license__, so this dependency chain would be legal: [2] App -- libGPL -- libBSD Apologies all ___ 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
Curt Sampson schrieb: Understanding the general techniques for this sort of thing and seeing where you're likely to need to apply them isn't all that difficult, once you understand the problem. (It's probably much easier if you don't have to work it out all for yourself, as I did. Someone needs to write the how to manage lazyness in Haskell guide.) My attempt in this direction: http://www.haskell.org/haskellwiki/Laziness_is_not_always_good http://www.haskell.org/haskellwiki/Maintaining_laziness ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GPL answers from the SFLC (WAS: Re: ANN: hakyll-0.1)
On Fri, Mar 5, 2010 at 09:38, Stephen Tetley stephen.tet...@gmail.com wrote: Hi Magnus The 'Why not LGPL' doesn't cover the particular argument here: using the ordinary GPL for a library makes it available only for free programs. The particular concern we have here is quite specific, considering (--) to be a dependency, can Hackage libraries under BSD3 that depend on libraries under GPL? [1] App -- libBSD3 -- libGPL Any App built has to incorporate the GPL library - so the App has to be GPL. -- No dispute --. Similar BSD3 is a GPL compatible library, so this dependency chain would be legal: [2] App -- libGPL -- libBSD The argument is whether it is legal to distribute (read host on Hackage) BSD3 libs that depend on GPL libs - formulation [1]. Now I'm even more confused. How is hosting on Hackage an issue in [1]? Both involved licenses are very liberal when it comes to distribution. The only issue I do see is that the author of libBSD3 is actually deluding her/him-self, since the use of libGPL means both libraries are in fact under GPL. I don't see this being anything that anyone involved with Hackage can be held responsible for, the responsibility must fall on the author of libBSD3. In this scenario I don't see Hackage as anything more than a conduit. /M -- Magnus Therning(OpenPGP: 0xAB4DFBA4) magnus＠therning．org Jabber: magnus＠therning．org http://therning.org/magnus identi.ca|twitter: magthe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GPL answers from the SFLC (WAS: Re: ANN: hakyll-0.1)
On 5 March 2010 09:53, Magnus Therning mag...@therning.org wrote: Now I'm even more confused. How is hosting on Hackage an issue in [1]? Hi Magnus The issue arouse when Tom Tobin spotted Hackage was hosting hakyll (libBSD3) that depends in pandoc (libGPL). Hakyll's author is allowed to privately write any code he wants that uses GPL code, Hackage come into it as he published on Hackage. Best wishes Stephen ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GPL answers from the SFLC (WAS: Re: ANN: hakyll-0.1)
On 5 March 2010 09:53, Magnus Therning mag...@therning.org wrote: Now I'm even more confused. How is hosting on Hackage an issue in [1]? The GPL specifically (and only) applies when code is distributed to others outside the originating authors' organisation. Hackage is a means of distributing such code. Because Hackage has received the code from the author, it therefore has the same obligations (under the GPL, or BSD, or whatever) as any other recipient. To be clear, like any recipient, one treats the donor in good faith. That is, one believes the license granted by the author (or upstream distributor) is valid until notified otherwise. It is the author's responsibility to check, not Hackage's. Regards, Malcolm ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GPL answers from the SFLC (WAS: Re: ANN: hakyll-0.1)
On Fri, Mar 5, 2010 at 2:19 AM, Stephen Tetley stephen.tet...@gmail.comwrote: On 5 March 2010 09:53, Magnus Therning mag...@therning.org wrote: Now I'm even more confused. How is hosting on Hackage an issue in [1]? Hi Magnus The issue arouse when Tom Tobin spotted Hackage was hosting hakyll (libBSD3) that depends in pandoc (libGPL). Hakyll's author is allowed to privately write any code he wants that uses GPL code, Hackage come into it as he published on Hackage. Yes the author can privately license code to himself under any license he wants, but when he distributes code based on GPL'd code, it has to be GPL'd. That's why people hate this license, or love this license. For all the freedom it talks about it's awfully restrictive. Dave Best wishes Stephen ___ 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] GPL answers from the SFLC (WAS: Re: ANN: hakyll-0.1)
As always I'm still not a lawyer, so this is not legal advice... but here's how I think it works. If you need to talk to a lawyer to get this cleared up, do it. On Fri, Mar 5, 2010 at 2:30 AM, Malcolm Wallace malcolm.wall...@cs.york.ac.uk wrote: On 5 March 2010 09:53, Magnus Therning mag...@therning.org wrote: Now I'm even more confused. How is hosting on Hackage an issue in [1]? The GPL specifically (and only) applies when code is distributed to others outside the originating authors' organisation. I'm pretty sure it says nothing about organizations. If I threw a flash stick with a binary of a program I wrote over my cubicle wall to say, my coworker, Steve, and I tried to tell him he couldn't have the source to my binary that I created based on a GPL'd program on that stick, he could say I've infringed on his rights under the GPL. Hackage is a means of distributing such code. Because Hackage has received the code from the author, it therefore has the same obligations (under the GPL, or BSD, or whatever) as any other recipient. Hackage has no obligations unless it's an intelligent entity. Hackage does not have to enforce the GPL, the author responsible for the perceived violation of the GPL must resolve it with the person claiming the violation, either by settling it inside or outside of court, by either making their code the GPL, or dealing with someone potentially bringing them in front of a judge. In fact the people running Hackage have now become the same as the person I threw my flash drive over the cube wall to, and have the same rights as Steve. To be clear, like any recipient, one treats the donor in good faith. That is, one believes the license granted by the author (or upstream distributor) is valid until notified otherwise. It is the author's responsibility to check, not Hackage's. EXACTLY :-) Now for a bit of personal reflection that you can ignore if you wish... Wouldn't it be excellent if Google could tell us just how many times innocent mailing lists like haskell-cafe have to put up with confusion over the GPL? Every single open source project I've ever been on has had a mailing list that has had this problem in the last 15 years I've been active in open source communities, and it just keeps rearing it's ugly head. It's really irritating and distracts people who'd rather be sharing their work with one another from doing so, completely thwarting the point of the FSF to begin with. As such I've long since abandoned any love for any form of the GPL, and much prefer licenses like the BSD license. 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] Books for advanced Haskell
On Thu, Mar 4, 2010 at 7:11 PM, Richard O'Keefe o...@cs.otago.ac.nz wrote: I assumed that CBL meant Call By Location Commercial Brewer's License? I think it's about beer! ___ 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] How to put data from a string to a tuple
Hi, Im self learner in Haskell. And im stuck in a small place which I tried searching in google but couldn't find Proper answer I have some values in a string, Im removing them one by one from the string (word by word) and I want to put them in a tuple. Because it contain Integers and Strings. Can someone help me __ Information from ESET NOD32 Antivirus, version of virus signature database 4917 (20100305) __ 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
Re: [Haskell-cafe] How to put data from a string to a tuple
Consider taking this to the haskell-beginners list. On Fri, Mar 5, 2010 at 4:32 AM, Pradeep Wickramanayake prad...@talk.lk wrote: Hi, Im self learner in Haskell. And im stuck in a small place which I tried searching in google but couldn't find Proper answer I have some values in a string, Im removing them one by one from the string (word by word) and I want to put them in a tuple. Because it contain Integers and Strings. Could you be more specific? Paste the code you have already, and be clearer about what you are trying to accomplish. Luke ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] How to obtain unique integers
I'm implementing a variant of Prolog in Haskell (yes, I know others already exist...) and am looking to solve the following issues: (1) I need to translate anonymous variables _ into unique variable names. Data.Unique does not give me a printable identifier. Is there another package that does this? (2) Is there a cabal package similar to the Atom.hs module form ginsu, that associates strings with unique hashes? The alternative of course is to maintain state variables and pass them along to display and parsing functions, but that makes it difficult to make the terms instances of Read/Show without reference to a global variable anyhow. Thanks, Rob ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GPL answers from the SFLC (WAS: Re: ANN: hakyll-0.1)
The GPL specifically (and only) applies when code is distributed to others outside the originating authors' organisation. I'm pretty sure it says nothing about organizations. http://www.gnu.org/licenses/gpl-faq.html#InternalDistribution Is making and using multiple copies within one organization or company “distribution”? No, in that case the organization is just making the copies for itself. As a consequence, a company or other organization can develop a modified version and install that version through its own facilities, without giving the staff permission to release that modified version to outsiders. However, when the organization transfers copies to other organizations or individuals, that is distribution. In particular, providing copies to contractors for use off-site is distribution. Regards, Malcolm___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Real-time garbage collection for Haskell
On 04/03/2010 09:14, Curt Sampson wrote: However: now that Simon's spent a bunch of time experimenting with the runtime's GC settings and found a set that's mitigated much of our problem, other things are pushing their way up my priority list. Between that and an upcoming holiday, I'm probably not going to get back to this for a few weeks. But I'd be happy to discuss my ideas with anybody else who's interested in similar things, even if just to know what would be useful to others. What settings are you using, out of interest? What do you guys think about setting up a separate mailing list for this? I have to admit, I don't follow haskell-cafe much due to the high volume of the list. (Thus my late presence in this thread.) I would be willing to keep much closer track of a low-volume list that dealt with only GC stuff. Please feel free to discuss on glasgow-haskell-users@ which is lower volume. I don't particularly like setting up new mailing lists unless there's likely to be an ongoing need - we have quite a few defunct lists on haskell.org now. I'd even be open to providing hosting for the list, using my little baby mailing list manager written in Haskell (mhailist). It's primitive, but it does handle subscribing, unsubscribing and forwarding of messages. Sure, that would be fine too. Cheers, Simon ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: How to obtain unique integers
Robert Rothenberg rob...@gmail.com wrote: I'm implementing a variant of Prolog in Haskell (yes, I know others already exist...) and am looking to solve the following issues: (1) I need to translate anonymous variables _ into unique variable names. Data.Unique does not give me a printable identifier. Is there another package that does this? (2) Is there a cabal package similar to the Atom.hs module form ginsu, that associates strings with unique hashes? The alternative of course is to maintain state variables and pass them along to display and parsing functions, but that makes it difficult to make the terms instances of Read/Show without reference to a global variable anyhow. Well, you can use hashUnique, but there are no guarantees about collisions. If you need thread safety, the easiest approach is an id generator thread like this: idVar - newEmptyMVar forkIO . mapM (putMVar idVar) $ [0..] let getId = takeMVar idVar If you don't need it, you will need to pass state around, just like with Data.Unique. Greets Ertugrul -- nightmare = unsafePerformIO (getWrongWife = sex) http://blog.ertes.de/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Real-time garbage collection for Haskell
On 05/03/2010 05:03, wren ng thornton wrote: Simon Marlow wrote: So it would be pretty easy to provide something like disableMajorGC, enableMajorGC :: IO () Of course leaving it disabled too long could be bad, but that's your responsibility. It seems like it'd be preferable to have an interface like: withMajorGCDisabled :: IO() - IO() or (for some definition of K): withMajorGCDisabled :: (K - IO()) - IO() Sure, my intention was that you'd build this with the primitives. in order to ensure that it always gets turned back on eventually. Of course, the latter can be created from the former pair. It's just that the former reminds me a bit much of explicit memory management and how difficult it is to balance the free()s... quite! Cheers, Simon ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Books for advanced Haskell
Hi, oh boy it took me a while to find this post again. Perhaps not exactly. I build monads left and right, but that's because I don't understand much else. :-) Before you get all hung up on them, though, I recommend reading The Typeclassopedia,[1], which will introduce you to all of the monad's friends and family. When you say that you use monads to the left and right, do you mean using pre-defined monad instances, or do you construct your own, ie. define something to be an instance of a monad and then write codes using that instance? Günther ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: GPL answers from the SFLC (WAS: Re: ANN: hakyll-0.1)
On Fri, 2010-03-05 at 01:42 -0700, Luke Palmer wrote: On Fri, Mar 5, 2010 at 12:53 AM, Kevin Jardine kevinjard...@yahoo.com wrote: I'm a Haskell newbie but long time open source developer and I've been following this thread with some interest. The GPL is not just a license - it is a form of social engineering and social contract. The idea if I use the GPL is that I am releasing free and open source software to the community. You are welcome to use it for any purpose but in exchange you must also agree to release any software you create that uses my software as free and open source. That is the difference between GPL and BSD type licenses. The GPL very deliberately creates an obligation. Yes, that can be inconvenient. It is meant to be inconvenient. Actually the GPL reminds me of a Haskell concept that I am struggling with right now - the monad. When I started writing Haskell code I was always trying to mix pure and IO code and I soon learned that once I used the IO monad I was stuck within it. The monad creates an inconvenient obligation and any IO code can only be used within other IO code. There are good reasons for monads (just as, in my view, there are good reasons for the GPL) but using them means that I need to make a lot of changes to the way I write software. Hmm. I believe that there are sufficient loopholes in GPL as library to not use it. Personally I follow such rules of thumb (for myself): - BSD3/MIT/... - Small code or BSD3 community - LGPL - Larger libraries - GPL - Programs BTW. What if package have multiply licenses? Cabal seems to not express following situations: - It is dual licensed - Library is LGPL but helper program is GPL - Part of library is on striker license but part of it is for example public domain (so it would be worth to note this) Sure. You can put a GPL license on any software: license :: a - GPL a And if you could have used some public domain package 'a' to create some GPL'd software, then you can use the GPL'd 'a' to create that same software. usage :: (a - GPL b) - GPL a - GPL b :-P Luke Hmm. IMHO it is more similar class Licence l where license :: Package a = a - l a class Licence l = GPLCompatible l where ... instance GPLCompatible GPL instance GPLCompatible LGPL ... liftToGPL :: (GPLCompatible l, Package a) = l a - GPL a Regards signature.asc Description: This is a digitally signed message part ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: GPL answers from the SFLC
Maciej Piechotka uzytkown...@gmail.com writes: BTW. What if package have multiply licenses? Cabal seems to not express following situations: - It is dual licensed - Library is LGPL but helper program is GPL - Part of library is on striker license but part of it is for example public domain (so it would be worth to note this) What seems to happen so far is that the library license is given in the Cabal file (as it has the most amount of code usually). For example, see the license for cpphs [1]; on Hackage it's listed as LGPL whereas the library is LGPL and the program is GPL. [1]: http://haskell.org/cpphs/ -- 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
[Haskell-cafe] Re: New OpenGL package: efficient way to convert datatypes?
Nick Bowler nbow...@elliptictech.com wrote: I meant to say that fromRational . toRational is not appropriate for converting values from one floating point type to another floating point type. It gets even worse: My GPU doesn't know about doubles and its floats aren't IEEE, at all (not that Haskell Doubles are guaranteed to be IEEE iirc) I think the situation calls for a split interface: One to satisfy the numericists / scientific IEEE users, and one to satisfy performance. -- (c) this sig last receiving data processing entity. Inspect headers for copyright history. All rights reserved. Copying, hiring, renting, performance and/or quoting of this signature prohibited. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: GPL answers from the SFLC
Stefan Monnier monn...@iro.umontreal.ca wrote: Note that this is a safety measure for the submitter: If the code is, indeed, released to the public, it is (dual licesed) GPL, anyway, even if that might not have been the intent. No. If the submitter did not explicitly release his code under the GPL, then it is not licensed under the GPL, even if is a derivative of GPL code. Instead, it is a breach of the GPL license and the submitter is exposing himself to a civil suit. ...I think for the majority of non-commercial developers (and even a lot of companies), the net result is the same. -- (c) this sig last receiving data processing entity. Inspect headers for copyright history. All rights reserved. Copying, hiring, renting, performance and/or quoting of this signature prohibited. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Benchmarking and Garbage Collection
Simon Marlow wrote: import Control.Concurrent import Control.Concurrent.CML import Control.Monad main :: IO () main = do let numChoices = 2 cs - replicateM numChoices channel mapM_ forkIO [replicateM_ (10 `div` numChoices) $ sync $ transmit c () | c - cs] replicateM_ 10 $ sync $ choose [receive c (const True) | c - cs] Good grief. Can I get a copy of this program? It might be something simple that we can fix. Just having lots of threads shouldn't be a performance problem per se, we have benchmarks that create millions of threads without any problems. That's all the code you need, along with the cml package from Hackage. Put the above few lines into GoodGrief.hs (the reply has munged the indentation slightly), and do: cabal install cml ghc --make -threaded GoodGrief.hs ./GoodGrief +RTS -s That got me the listed results on GHC 6.12.1 (I did use -threaded but not -N as I was on a single-core machine; I believe the same problem occurs without -threaded). The problem is in the CML library that the above code uses. Neil. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: A few ideas about FRP and arbitrary access in time
I'm not sure I want to follow WWRD all the way. I do want events, for example mouse clicks (for which there doesn't seem to be any logical behavior representation). As you note the pull-based approach does a lot more work in those cases than seems necessary. Events are indispensable for practically all applications, even those that have continuous output, so leaving them out would be no option. I only did so for Elerea to be able to quickly get a working system running, so I can actually experiment with application-side design. But yeah, it can't be used for serious purposes without some support for events. In any case, what I'm discussing in that report is mostly centered on the continuous-time values, so I'm more concerned with what we call behaviors. The question is how to model memory-full operations with point-wise operations. I think it would help if you tried to solve more specific problems first and see what common structure you can factor out from the solutions. It's easy to get into a dead end if you go for the big picture right away. Right. You'll agree that it would be nice to have a general approach? How will that work? That's what I'd like to find out. And I do hope you'll manage to find a useful result. My intuition says, however, that looking for a sensible interface between events and behaviours is more fruitful than trying to unify these two notions. The reason is the difference in TCMs, as noted previously. report. I'd like things to be unified, so maybe playing with the idea of a total function to 'Maybe a' for events is the right direction. I think this was already explored by some FRP incarnations, but I don't recall what came out of it. Yes, that's the Yampa way. The problem is that in this case you'll need an awkward operator to refer to 'the time of last defined point'. But isn't Lucid Synchrone essentially discrete-timed? Also, events shouldn't be semantically constrained to multiples of some basic clock, they are defined over continuous time. Of course, it's more like a possible model for operational semantics (I know you're interested in denotation, but inspiration can come from anywhere). I just thought that clock calculus might be an interesting topic to throw into the hat. Gergely -- http://www.fastmail.fm - Email service worth paying for. Try it for free ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Books for advanced Haskell
2010/3/5 Günther Schmidt gue.schm...@web.de: When you say that you use monads to the left and right, do you mean using pre-defined monad instances, or do you construct your own, ie. define something to be an instance of a monad and then write codes using that instance? Hi Günther One view of Monads (in the context of Haskell) is that they provide effects: - State Monad - state - Maybe monad - partiality (answer or failure) - Error monad - partiality with some answer type for the failure (variation of Maybe) - Environment monad aka Reader - read only access to context - Writer monad - tracing - write only access to context - List monad - non-determinism - Resumption monad - interleaving for (simulating) concurrency Because a monad (in the context of Haskell) is an implementation of the Monad type class and the obligation to satisfy the monad laws, there are quite few 'variations on a theme' monads e.g.: Jerzy Karczmarczuk's time travel State Monad http://users.info.unicaen.fr/~karczma/arpap/revpearl.pdf Ralf Hinze's - partial CPS monad Typed Quote/Antiquote -- paper currently off-line unfortunately The codensity monad - variation on the CPS monad http://www.cs.nott.ac.uk/~gmh/wrapper2.pdf Plus unique but currently rare monads, e.g: Probability http://web.engr.oregonstate.edu/~erwig/papers/PFP_JFP06.pdf These latter monads still represent effects, and one should be able to define them as transformers (I think, I haven't actually tried), but they less common presumably because people have found less need for the effects they provide. There are also monads where I'd struggle to claim any analogous 'effect' (maybe they have one and I don't understand the presentation, or maybe they don't actually have one) - generally these monads don't seem to have escaped from the mathematical world to the Haskell world. E.g. the monad of locales, power locales http://www.cs.bham.ac.uk/~mhe/papers/pinjective.pdf To work with monads in Haskell its not ignoble simple to decide what effect or combination of effects you want and use the relevant monad (for a single effect) or build a transformer (for multiple effects). Best wishes Stephen ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: GPL answers from the SFLC (WAS: Re: ANN: hakyll-0.1)
David Leimbach leim...@gmail.com wrote: Yes the author can privately license code to himself under any license he wants, but when he distributes code based on GPL'd code, it has to be GPL'd. That's why people hate this license, or love this license. For all the freedom it talks about it's awfully restrictive. It has to be lincensed under GPL, but GPL doesn't have to be the only license. Consider, for example, releasing an app that depends on readline (GPL) under GPL/BSD: People may use+distribute it under GPL, they may hack it to remove the readline dependency and use and distribute it under either GPL, BSD, or both, or someone could come along and re-implement readline (guess what has happened) and everybody will be able to choose between GPL, BSD, or both, again. The GPL is viral, but it doesn't (and can't) prevent you from releasing _your_ code under -- additionally -- any bleeding license you wish[1]. It could also be argued that, as BSD explicitely allows re-lincensing, that any grant of a BSD-license implies a dual-license under GPL, as everyone and everybody can just re-license the code as such. BSD also does not claim that the lincensed code is not allowed to be used under GPL, and it does not guarantee FITNESS FOR ANY PURPOSE, which includes, but is not limited to, being distributable under violation of GPL. This, admittedly, isn't a bullet-proof argument. I'd be surpised, though, if any court would see _intent_ of closing up GPL'ed code if you release it under terms _that allow, but not by themselves enforce,_ GPL distribution. However, (apart from IANAL and whether or not above argument holds), not mentioning that your code depends on GPL and thus can't be distributed in violation of it is clearly a mean, aweful breach of the principle of least surprise and is therefore to be fought with any static means we have at our disposal: % cabal sdist foo.cabal: Error: Depends on a GPL library but only mentions BSD3 as license. Either change License: to include GPL or remove the offending dependency. Please, please don't make this a mere warning. It's easy and painless enough to fix and will result in way less confusion about what terms some random piece of hackage code can be used under. [1] I strongly advice dual-licensing any BSD code under the Beer License, regardless of GPL involvement. -- (c) this sig last receiving data processing entity. Inspect headers for copyright history. All rights reserved. Copying, hiring, renting, performance and/or quoting of this signature prohibited. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell platform for GHC 6.12.1?
Does this release include a new Haskell Platform for Snow Leopard as well? Best, On 4 March 2010 18:30, Don Stewart d...@galois.com wrote: bugfact: Using GHC 6.12.1 on Windows currently is hard, since one must compile the latest version of cabal-install, which is a nightmare to do for a typical windows user (install mingw, msys, utils like wget, download correct package from hackage, compile them in correct order, etc etc) What's the status of the Haskell platform for the latest and greatest Glasgow Haskell Compiler? We've just entered the release phase, http://trac.haskell.org/haskell-platform/wiki/ReleaseTimetable And you can expect 2010.2 during ZuriHac. Thanks for checking in! -- Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Ozgur Akgun ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Benchmarking and Garbage Collection
On 05/03/2010 13:45, Neil Brown wrote: Simon Marlow wrote: import Control.Concurrent import Control.Concurrent.CML import Control.Monad main :: IO () main = do let numChoices = 2 cs - replicateM numChoices channel mapM_ forkIO [replicateM_ (10 `div` numChoices) $ sync $ transmit c () | c - cs] replicateM_ 10 $ sync $ choose [receive c (const True) | c - cs] Good grief. Can I get a copy of this program? It might be something simple that we can fix. Just having lots of threads shouldn't be a performance problem per se, we have benchmarks that create millions of threads without any problems. That's all the code you need, along with the cml package from Hackage. Put the above few lines into GoodGrief.hs (the reply has munged the indentation slightly), and do: cabal install cml ghc --make -threaded GoodGrief.hs ./GoodGrief +RTS -s That got me the listed results on GHC 6.12.1 (I did use -threaded but not -N as I was on a single-core machine; I believe the same problem occurs without -threaded). The problem is in the CML library that the above code uses. Yes, I see what the problem is. Removing a thread from the queue attached to an MVar is a O(n) operation, and in this case you have thousands of threads attached to MVars and the system wants to clean them all up before exiting, hence things go O(n^2). Threads only need to be removed from the queue when - they are the target of throwTo from another thread - the system is shutting down, and deleting threads - the thread is unreachable and needs to be woken up to be sent the BlockedIndefinitelyOnMVar exception (this is probably why you sometimes get the 60s GC just after your benchmark has finished, but before shutdown). So as it happens Simon PJ and I were discussing some changes yesterday that will eventually make removing a thread from a queue an O(1) operation. Hopefully 6.14.1 will be better in this regard. Cheers, Simon ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Hackage vs. legacy support in Cabal files
I'd like to support Hackage and GHC 6.8 with one source distribution. The enclosed Cabal file would do the trick if Hackage would simply evaluate the Cabal file using the default flag values. Instead, it chokes on a hack required to support GHC 6.8. The directory containing the autogen files has to be on the source path. if flag(old) Hs-Source-Dirs: src dist/build/autogen else Hs-Source-Dirs: src Is there a way to force Hackage to respect flag values? John cpsa.cabal Description: Binary data ___ 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?
On Fri, Mar 5, 2010 at 4:07 PM, Johan Tibell johan.tib...@gmail.com wrote: I think I would use the module system for namespacing rather than using function prefixes. Like so: import Text.Html as E import qualified Text.Html.Attribute as A E.html ! [A.class_ my-class] (... more combinators ...) (Assuming that ! is used to introduce attributes.) This allows you to use the element names and/or the attribute names unclassified if you so desire. html ! [class_ my-class] (... more combinators ...) Function names in the 'html' library are unpredictable from corresponding element/attribute names... (head, base, a = header, thebase, anchor) I'm of the same opinion. The combinators should match the element/attribute names as far as possible. The rule that I had in mind was that the combinators should have exactly the same name as the corresponding element/tag except when the name collides with a keyword (e.g. class). If the name collides with a keyword we could e.g. always append a _. That's fine. However, I think no one uses unqualified import actually because of conflict with basic functions (head, id, map) and existent of single character functions (a, b, i, p). Anyway, I like the project. Thanks, iquiw ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Anyone up for Google SoC 2010?
Johan Tibell johan.tib...@gmail.com wrote: = A high-performance HTML combinator library using Data.Text = May I add * Conceptual compatiblity with the W3C DOM. The library shoud be designed in a way that allows a thin / automatically generated wrapping layer to support DOM operations, where applicable. ? It is a keep that in mind, not absolute, requirement. -- (c) this sig last receiving data processing entity. Inspect headers for copyright history. All rights reserved. Copying, hiring, renting, performance and/or quoting of this signature prohibited. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: GPL answers from the SFLC
Ivan Lazar Miljenovic ivan.miljeno...@gmail.com wrote:
For example, see the license for cpphs [1]; on Hackage it's listed as
LGPL whereas the library is LGPL and the program is GPL.
Output from GPL programs is licensed under whatever license its input
is licensed under (that is, the GPL doesn't say anything and forbids
additional usage restrictions), I think the most prominent example is
gcc, which you may use to develop closed-source programs.
It's common to see programs under GPL and standard library code that is
included by default under less restrictive licenses: If GHC was GPL,
chances would be high that the RTS, itself, would still be licensed
under BSD or similar. Doing otherwise just invites either forks or a
community that is completely lacking any commercial members, both of
which are usually not intended, at all.
...but that doesn't answer why cpphs is GPL/LGPL (as it does not
inject any standard library code into its output[1]). I think it's the
usual reason: The author generally wants GPL, but doesn't mind if anyone
develops another program that does something the library part can be
used for.
[1] At least in Germany, there's no way in hell you could claim
copyright on injected {-# LINE #-} pragmas (Schaffungshoehe). I
will pity you if that's possible under your legislation
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Re: [Haskell-cafe] Re: New OpenGL package: efficient way to convert datatypes?
On 14:30 Fri 05 Mar , Achim Schneider wrote: Nick Bowler nbow...@elliptictech.com wrote: I meant to say that fromRational . toRational is not appropriate for converting values from one floating point type to another floating point type. It gets even worse: My GPU doesn't know about doubles and its floats aren't IEEE, at all (not that Haskell Doubles are guaranteed to be IEEE iirc) AFAIK, GLDouble is a newtype wrapper around CDouble, though, and doesn't correspond to a GPU-internal type. Even if it did, if we are converting to a type that doesn't support infinities, then is is reasonable for the conversion to not support them, either. I'd want to see a call to error in this case, but perhaps allowing unsafe optimisations (see below). I think the situation calls for a split interface: One to satisfy the numericists / scientific IEEE users, and one to satisfy performance. I think this is a job for the compiler rather than the interface. For example, GCC has -ffinite-math-only, -fno-signed-zeros, etc., which allow the compiler to make assumptions about the program that would not normally be valid. Nevertheless, for the issue at hand (Double=CDouble=GLDouble), there is a conversion interface that should satisfy everyone (both fast and correct): the one that compiles to nothing at all. -- Nick Bowler, Elliptic Technologies (http://www.elliptictech.com/) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Books for advanced Haskell
Stephen Tetley wrote: To work with monads in Haskell its not ignoble simple to decide what effect or combination of effects you want and use the relevant monad (for a single effect) or build a transformer (for multiple effects). ... or use the free term algebra approach outlined in http://apfelmus.nfshost.com/articles/operational-monad.html when the semantics of the effects are a bit tricky to fit into existing transformers. My package operational http://projects.haskell.org/operational/ contains a bunch of examples. Regards, Heinrich Apfelmus -- http://apfelmus.nfshost.com ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] How to put data from a string to a tuple
As luke requested Here is the codes and some more brief explanation. Please help me getItemFile :: IO String getItemFile = do test - readFile input.txt return test im taking a file data to a string it contains string like hello,world,I,am,a,new,developer so I need to put these each to a tuple. Because the content have Integers and Strings sortList2 :: String - String sortList2 (x:xs) | x == ',' = | otherwise = [x] ++ sortList2 xs Im breaking word by word from this above function Now I need to send it to a tuple. Can someone help me how to do it. Is this possible. Using recursion im checking each word till , occurs And taking that string and passing it to the tuple. Can someone please help me to do it. Please ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Anyone up for Google SoC 2010?
On Fri, Mar 5, 2010 at 3:46 PM, Achim Schneider bars...@web.de wrote: Johan Tibell johan.tib...@gmail.com wrote: = A high-performance HTML combinator library using Data.Text = May I add * Conceptual compatiblity with the W3C DOM. The library shoud be designed in a way that allows a thin / automatically generated wrapping layer to support DOM operations, where applicable. ? It is a keep that in mind, not absolute, requirement. I'm not quite sure I understand what you have in mind. Do you mean that given a value of type Html you can e.g. query by ID to find children? Cheers, Johan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] vector stream fusion, inlining and compilation time
This is a general problem when working with RULES-based
optimisations. Here is an example of what happens: suppose we have
foo :: Vector Int - Vector Int
foo xs = map (+1) xs
Now, GHC will generate a nice tight loop for this but if in a
different module, we have something like this:
bar xs = foo (foo xs)
then this won't fuse because (a) foo won't be inlined and (b) even if
GHC did inline here, it would inline the nice tight loop which can't
possibly fuse instead of the original map which can. By slapping an
INLINE pragma on foo, you're telling GHC to (almost) always inline the
function and to use the original definition for inlining, thus giving
it a chance to fuse.
thanks for the insight, roman!
the downside after adding the INLINE pragmas is that now some of my modules
take
_really_ long to compile (up to a couple of minutes); any ideas where i can
start looking to bring the compilation times down again?
Alas, stream fusion (and fusion in general, I guess) requires what I
would call whole loop compilation - you need to inline everything into
loops. That tends to be slow. I don't know what your code looks like
but you could try to control inlining a bit more. For instance, if you
have something like this:
foo ... = ... map f xs ...
where
f x = ...
you could tell GHC not to inline f until fairly late in the game by adding
{-# INLINE [0] f #-}
to the where clause. This helps sometimes.
thanks, i'll check it out.
I'm surprised -Odph doesn't produce faster code than -O2. In any
case, you could try turning these flags on individually (esp.
-fno-method-sharing and the spec-constr flags) to see how they affect
performance and compilation times.
in the end it turned out that i had forgotten another INLINE pragma and in my
crude benchmarks -O2 and -Odph give basically the same results, -O2 being a
little faster. i hope i'll have time next week to do proper benchmarks, and i
also want to try ghc HEAD with the llvm patches.
conv_1 conv_2 conv_3
-Odph 1.004 2.715 1.096
-O2 1.000 2.710 1.097
i'm still curious, though, why my three versions of direct convolution perform
so differently (see attached file). in particular, i somehow expected conv_3 to
be the slowest and conv_2 to perform similar to conv_1. any ideas? i haven't had
a look at the core yet, mainly because i'm lacking the expertise ...
sk
import Data.Vector.Generic (Vector, (!))
import qualified Data.Vector.Generic as V
conv_1, conv_2, conv_3 :: (Num a, Vector v a) = v a - v a - v a
{-# INLINE conv_1 #-}
conv_1 h x = V.generate (l+m) f
where
m = V.length h - 1
l = V.length x
{-# INLINE f #-}
f n = g 0 n (max 0 (n-l+1)) (min n m)
g y n m k = if m = k
then let y' = y + (h ! m) * (x ! (n-m))
in y' `seq` g y' n (m+1) k
else y
{-# INLINE conv_2 #-}
conv_2 h x = V.generate (l+m) f
where
l = V.length x
m = V.length h - 1
{-# INLINE f #-}
f n = let j = max 0 (n-l+1)
k = (min n m) - j + 1
in V.sum (V.zipWith (*) (V.slice j k h) (V.reverse (V.slice (n -
j - k + 1) k x)))
{-# INLINE conv_3 #-}
conv_3 h x = V.generate (l+m-1) f
where
m = V.length h
l = V.length x
p = V.replicate (m-1) 0
x' = p ++ x ++ p
{-# INLINE f #-}
f i = V.sum (V.zipWith (*) (V.reverse h) (V.slice i m x'))
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Re: [Haskell-cafe] Haskell platform for GHC 6.12.1?
Ozgur Akgun ozgurak...@gmail.com writes: Does this release include a new Haskell Platform for Snow Leopard as well? It should, yes. G -- Gregory Collins g...@gregorycollins.net ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Anyone up for Google SoC 2010?
Johan Tibell johan.tib...@gmail.com wrote: On Fri, Mar 5, 2010 at 3:46 PM, Achim Schneider bars...@web.de wrote: Johan Tibell johan.tib...@gmail.com wrote: = A high-performance HTML combinator library using Data.Text = May I add * Conceptual compatiblity with the W3C DOM. The library shoud be designed in a way that allows a thin / automatically generated wrapping layer to support DOM operations, where applicable. ? It is a keep that in mind, not absolute, requirement. I'm not quite sure I understand what you have in mind. Do you mean that given a value of type Html you can e.g. query by ID to find children? The overall idea is that if we chose to write a browser in Haskell, which will come with an ECMAscript implementation in Haskell, it'd be nice if that HTML library could be developed into something that can be used as internal DOM representation (and messed with from the ECMAscript side) without breaking the already existing Haskell interface. Also, web developers that know DOM inside out shouldn't be alienated by Haskell doing things in a way that isn't compatible with their intuition about how DOM/HTML works. That is, the library should show potential to be queryable (with some generics library) with the same semantics as DOM, meaning that the information necessary to do that should be present. ...I don't mean that the library as implemented for the SoC must support such queries, but that e.g. a (to be written) library with the same haskell combinators that spews out an ADT instead of a string should be. -- (c) this sig last receiving data processing entity. Inspect headers for copyright history. All rights reserved. Copying, hiring, renting, performance and/or quoting of this signature prohibited. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to put data from a string to a tuple
Let's first discuss what a tuple is. Here[1] it says, A tuple is a fixed-size collection of values, where each value can have a different type. So they are of fixed-size and they can have values of different types. I am guessing the reason you want to use a tuple os that you want your collection object to be able to handle different types. But what about the fixed size bit? If you want to just have those values in a collection, the easiest thing you can do is putting them into a list. The problem with lists is that the elements in them need to be of same type. If you just want every word, as a string, it is easy. If you want to have _either strings or ints_ within the list, then you need to define a data type which holds either strings or ints, and have a list of this type. Just an example, import Data.Char(isDigit) testString = hello world 13 i am a new 37 developer 82 data StringOrInt = S String | I Int deriving (Eq,Ord,Show) readInt :: String - Int readInt = read toStringOrInt :: String - StringOrInt toStringOrInt x | all isDigit x = I (readInt x) | otherwise = S x test = map toStringOrInt (words testString) -- Output: [S hello,S world,I 13,S i,S am,S a,S new,I 37,S developer,I 82] Note: I changed the separator from commas to spaces, for the sake of easiness and understandablity. Hope this helps in some way. [1] http://book.realworldhaskell.org/read/types-and-functions.html On 5 March 2010 15:52, Pradeep Wickramanayake prad...@talk.lk wrote: As luke requested Here is the codes and some more brief explanation. Please help me getItemFile :: IO String getItemFile = do test - readFile input.txt return test im taking a file data to a string it contains string like “hello,world,I,am,a,new,developer” so I need to put these each to a tuple. Because the content have Integers and Strings sortList2 :: String - String sortList2 (x:xs) | x == ',' = | otherwise = [x] ++ sortList2 xs Im breaking word by word from this above function Now I need to send it to a tuple. Can someone help me how to do it. Is this possible. Using recursion im checking each word till “,” occurs And taking that string and passing it to the tuple. Can someone please help me to do it. Please __ Information from ESET NOD32 Antivirus, version of virus signature database 4918 (20100305) __ 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 -- Ozgur Akgun ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Anyone up for Google SoC 2010?
If it uses only one type for elements and perhaps another for attributes, Uniplate should fit any traversal needs perfectly. E.g., getElementByID: listToMaybe [ e | e - universe doc, elemID e == target_id ] or similar. This is doing essentially a depth-first search, so if this is a common operation, you'd need some further optimisation, but then I'm not convinced raw HTML is a good internal representation anyway. On 5 March 2010 16:20, Achim Schneider bars...@web.de wrote: Johan Tibell johan.tib...@gmail.com wrote: On Fri, Mar 5, 2010 at 3:46 PM, Achim Schneider bars...@web.de wrote: Johan Tibell johan.tib...@gmail.com wrote: = A high-performance HTML combinator library using Data.Text = May I add * Conceptual compatiblity with the W3C DOM. The library shoud be designed in a way that allows a thin / automatically generated wrapping layer to support DOM operations, where applicable. ? It is a keep that in mind, not absolute, requirement. I'm not quite sure I understand what you have in mind. Do you mean that given a value of type Html you can e.g. query by ID to find children? The overall idea is that if we chose to write a browser in Haskell, which will come with an ECMAscript implementation in Haskell, it'd be nice if that HTML library could be developed into something that can be used as internal DOM representation (and messed with from the ECMAscript side) without breaking the already existing Haskell interface. Also, web developers that know DOM inside out shouldn't be alienated by Haskell doing things in a way that isn't compatible with their intuition about how DOM/HTML works. That is, the library should show potential to be queryable (with some generics library) with the same semantics as DOM, meaning that the information necessary to do that should be present. ...I don't mean that the library as implemented for the SoC must support such queries, but that e.g. a (to be written) library with the same haskell combinators that spews out an ADT instead of a string should be. -- (c) this sig last receiving data processing entity. Inspect headers for copyright history. All rights reserved. Copying, hiring, renting, performance and/or quoting of this signature prohibited. ___ 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
Re: [Haskell-cafe] GPL answers from the SFLC (WAS: Re: ANN: hakyll-0.1)
Pending an explicit response from the SFLC, I decided to ask the FSF themselves what they thought of the Hackage/cabal situation. Specifically, I asked this: There is a website, 'Hackage' (http://hackage.haskell.org) that hosts source code packages for Haskell libraries and programs. The site hosts *only* source code, along with (text) descriptions of the packages. Each package hosted by the site is either source code for a library, for a program, or for both. In the package description, a package author specifies what license applies to the source code, the common choices being LGPL, GPL, or BSD3. The package author also specifies what other packages in the repository the package may require to compile successfully. The controversy in the community of users who use Hackage is whether or not it is a violation of the GPL for a package to be uploaded to Hackage specifying (for example) a BSD3 license for the code in the package, but also specifying that another package is a requirement for compilation, where that other package has been uploaded specifying (a version of) the GPL as its license. The opinion of many in the community is that since Hackage hosts only source code, and does not in any way combine packages (any combination of packages is created when a user chooses to download and compile and link the individual packages) there is no problem: there are no 'derived works' combining GPL and non-GPL being distributed on the site. Others believe that having a non-GPL package have as a dependency a GPL package is a problem for both the package author and for Hackage; that this in some way violates the GPL. I don't believe this sort of situation is clearly addressed in your FAQ (at least not to the satisfaction of the Hackage user community). There's a certain amount of fear, uncertainty and doubt being spread about usage of the GPL on Hackage, which it would be great to dispel (or, confirm, as necessary). Someone from the FSF responded as follows: A work which extends or requires a GPL work will generally also need to be released under the GPL, unless the GPL work provides a specific exception for that case. You are already familiar with the FAQ; however, please note http://www.fsf.org/licensing/licenses/gpl-faq.html#OOPLang and http://www.fsf.org/licensing/licenses/gpl-faq.html#MereAggregation . There is no magic to the act of linking, compiling, or a function invocation; these are not defining moments. It is the level of integration and dependency which will define whether one work is a derivative of another. Ultimately, the decision that one work is a derivative of another is a legal one which a court may have to decide for a particular case; a lawyer can give you a legal opinion. However, a good rule of thumb would be: if P is a GPL work, and Q is a work that would not function without P, then Q is probably a derivative of P and should only be conveyed to a third party or the public under a GPL license, in compliance with the license for P. I hope that helps. Thank you for your interest in free software! I am not a lawyer and the above is not legal advice. The opinions expressed above do not constitute an official position of the Free Software Foundation. Luigi Bai FSF Associate Member Volunteer, licens...@gnu.org Of course, given the disclaimer at the bottom, this opinion is officially no better than any of our opinions on the matter. Nevertheless, I would at least believe based on the above that this is what the FSF *wants* the GPL to mean, and, by extension, would assume, barring other evidence that this is what someone who chooses the GPL *wants* it to mean, and in licensing any software that I write that depends on someone else's GPL'd software, I'd respect those desires (without at all suggesting that this has any bearing on how the GPL would actually be interpreted in court). There's still a lot of gray area here -- the mere existence of a dependency doesn't imply that a software package is useless without the dependency, so there are many situations in which P could depend on Q and not be a derivative of Q, because the dependency can be disabled in some way and the software would still function. As an example -- pandoc can be built with or without highlighting-kate, and is useful either way. They're both GPL and by the same author, so there's no issue, but were that not the case it would seem obvious that pandoc isn't derivative of -kate, and thus could (by this reasoning) be released independently under different terms. The same may not be true of the hakyll / pandoc situation which sparked this controversy. Cheers, Rob ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: GPL answers from the SFLC (WAS: Re: ANN: hakyll-0.1)
On Thu, Mar 4, 2010 at 11:34 AM, Tom Tobin korp...@korpios.com wrote: After politely pestering them again, I finally heard back from the Software Freedom Law Center regarding our GPL questions (quoted below). I exchanged several emails to clarify the particular issues; in short, the answers are No, No, N/A, and N/A. The SFLC holds that a library that depends on a GPL'd library must in turn be GPL'd, even if the library is only distributed as source and not in binary form. They offered to draft some sort of explicit response if we'd find it useful. Several people expressed interest in a more explicit and official response from the SFLC, so I'm going to ask them if it would be possible to receive one that the Haskell community could use to help us resolve GPL licensing questions. I'll follow up again once I receive that. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GPL answers from the SFLC (WAS: Re: ANN: hakyll-0.1)
This seems really confusing. It would imply that if I write a library that is designed to talk to some part of the linux kernel API (which is GPL'd) then I'd have to release my library under the GPL. And anything that used my libraries API would need to be GPL'd too, etc... Which would mean that everything run in linux would need to be GPL'd, which is just silly. - Job On Fri, Mar 5, 2010 at 12:22 PM, Robert Greayer robgrea...@gmail.comwrote: Pending an explicit response from the SFLC, I decided to ask the FSF themselves what they thought of the Hackage/cabal situation. Specifically, I asked this: There is a website, 'Hackage' (http://hackage.haskell.org) that hosts source code packages for Haskell libraries and programs. The site hosts *only* source code, along with (text) descriptions of the packages. Each package hosted by the site is either source code for a library, for a program, or for both. In the package description, a package author specifies what license applies to the source code, the common choices being LGPL, GPL, or BSD3. The package author also specifies what other packages in the repository the package may require to compile successfully. The controversy in the community of users who use Hackage is whether or not it is a violation of the GPL for a package to be uploaded to Hackage specifying (for example) a BSD3 license for the code in the package, but also specifying that another package is a requirement for compilation, where that other package has been uploaded specifying (a version of) the GPL as its license. The opinion of many in the community is that since Hackage hosts only source code, and does not in any way combine packages (any combination of packages is created when a user chooses to download and compile and link the individual packages) there is no problem: there are no 'derived works' combining GPL and non-GPL being distributed on the site. Others believe that having a non-GPL package have as a dependency a GPL package is a problem for both the package author and for Hackage; that this in some way violates the GPL. I don't believe this sort of situation is clearly addressed in your FAQ (at least not to the satisfaction of the Hackage user community). There's a certain amount of fear, uncertainty and doubt being spread about usage of the GPL on Hackage, which it would be great to dispel (or, confirm, as necessary). Someone from the FSF responded as follows: A work which extends or requires a GPL work will generally also need to be released under the GPL, unless the GPL work provides a specific exception for that case. You are already familiar with the FAQ; however, please note http://www.fsf.org/licensing/licenses/gpl-faq.html#OOPLang and http://www.fsf.org/licensing/licenses/gpl-faq.html#MereAggregation . There is no magic to the act of linking, compiling, or a function invocation; these are not defining moments. It is the level of integration and dependency which will define whether one work is a derivative of another. Ultimately, the decision that one work is a derivative of another is a legal one which a court may have to decide for a particular case; a lawyer can give you a legal opinion. However, a good rule of thumb would be: if P is a GPL work, and Q is a work that would not function without P, then Q is probably a derivative of P and should only be conveyed to a third party or the public under a GPL license, in compliance with the license for P. I hope that helps. Thank you for your interest in free software! I am not a lawyer and the above is not legal advice. The opinions expressed above do not constitute an official position of the Free Software Foundation. Luigi Bai FSF Associate Member Volunteer, licens...@gnu.org Of course, given the disclaimer at the bottom, this opinion is officially no better than any of our opinions on the matter. Nevertheless, I would at least believe based on the above that this is what the FSF *wants* the GPL to mean, and, by extension, would assume, barring other evidence that this is what someone who chooses the GPL *wants* it to mean, and in licensing any software that I write that depends on someone else's GPL'd software, I'd respect those desires (without at all suggesting that this has any bearing on how the GPL would actually be interpreted in court). There's still a lot of gray area here -- the mere existence of a dependency doesn't imply that a software package is useless without the dependency, so there are many situations in which P could depend on Q and not be a derivative of Q, because the dependency can be disabled in some way and the software would still function. As an example -- pandoc can be built with or without highlighting-kate, and is useful either way. They're both GPL and by the same author, so there's no issue, but were that not the case it would seem obvious
Re: [Haskell-cafe] GPL answers from the SFLC (WAS: Re: ANN: hakyll-0.1)
On Fri, Mar 5, 2010 at 2:59 PM, Job Vranish job.vran...@gmail.com wrote: This seems really confusing. It would imply that if I write a library that is designed to talk to some part of the linux kernel API (which is GPL'd) then I'd have to release my library under the GPL. And anything that used my libraries API would need to be GPL'd too, etc... Which would mean that everything run in linux would need to be GPL'd, which is just silly. Linux license specifically single that case out of the license restrictions. From the COPYING file in linux's source: NOTE! This copyright does *not* cover user programs that use kernel services by normal system calls - this is merely considered normal use of the kernel, and does *not* fall under the heading of derived work. Also note that the GPL below is copyrighted by the Free Software Foundation, but the instance of code that it refers to (the Linux kernel) is copyrighted by me and others who actually wrote it. Also note that the only valid version of the GPL as far as the kernel is concerned is _this_ particular version of the license (ie v2, not v2.2 or v3.x or whatever), unless explicitly otherwise stated. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GPL answers from the SFLC (WAS: Re: ANN: hakyll-0.1)
On Fri, Mar 05, 2010 at 12:29:15PM +, Malcolm Wallace wrote: Background: X is a library distributed under the terms of the GPL. Y is another library which calls external functions in the API of X, and requires X to compile. X and Y have different authors. 1) Can the author of Y legally distribute the *source* of Y under a non-GPL license, such as the 3-clause BSD license or the MIT license? I believe the answer you got from SFLC (no) contradicts what the authors of the GPL say about this case. viz: http://www.gnu.org/licenses/gpl-faq.html#LinkingWithGPL Yes, to my knowledge what the SFLC said is also incorrect. Perhaps they just erred on the side of 'just GPL it'. In any case, I wouldn't want cabal/hackage to worry about such things for random uploaded packages, it can't know if the GPL licenses have special exceptions or whatnot. Unless of course someone where to write a formal combinator language for expressing legal contracts.. :). 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] Re: GPL answers from the SFLC (WAS: Re: ANN: hakyll-0.1)
Hi Kevin, I just wanted to say that's a very nice analogy. Thanks! ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GPL answers from the SFLC (WAS: Re: ANN: hakyll-0.1)
Hi, On Fri, Mar 05, 2010 at 01:16:18AM +0300, Bulat Ziganshin wrote: [...] The SFLC holds that a library that depends on a GPL'd library must in turn be GPL'd, even if the library is only distributed as source and not in binary form. Was this a general statement yes. it's soul of GPL idea, and it's why BG called GPL a virus :) Oh, BSD3 or ISC licensed code is viral as well, but only on the source code level ;-) (if you redistribute the sources, you have to leave the license and the copyright marker intact) Anyway, I really think the SFLC people are telling lies here (or, as someone else wrote in this thread, are telling what they whish the GPL to imply). Applying some common sense tells me: If you write some code (library or program) that depends on some GPL licensed library, you can still redistribute your *source code* under whatever license you want, as long as your source code distribution does not contain copies (original or modified) from the GPL'd stuff it depends on. For binary products created from such a library combo, you have to apply the GPL, which should be fine if *your* code is BSD3 or ISC or something similar. But nobody can force you to apply a specific license to your *source code*, even if the binary (links against/calls functions provided by) a GPL'd library. Oh, and for the discussion about wether APIs may be license-worth, which also popped up in this thread; /* * Copyright (c) 2010 Matthias Kilian k...@outback.escape.de * * All rights reserverd. */ extern int foo(double bar); If you ever dare to write some C function `foo' that takes a double and returns an int, I'll sue you to death ;-) Yes, there are APIs more inventive than that example above, but they're just *interfaces*. There has to be a lot of brain used on some interface to make it a creative work. (Oh, monads jump to mind) Ciao, Kili ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell platform for GHC 6.12.1?
GHC 6.12 changed the format of the internal package database. Only cabal-install 0.8 can read this format properly. Version 0.8 is only available on Hackage, the binaries available are cabal-install 0.6.2. I assume part of the platform release effort is to create new cabal-install binaries. On 4 March 2010 18:41, Andrew Coppin andrewcop...@btinternet.com wrote: Peter Verswyvelen wrote: Using GHC 6.12.1 on Windows currently is hard, since one must compile the latest version of cabal-install, which is a nightmare to do for a typical windows user Out of curiosity, why do you need to compile the latest version of cabal-install? Why can't you use the precompiled one? ___ 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
Re: [Haskell-cafe] How to obtain unique integers
The value-supply package [1] provides means to generate unique values of any kind. It uses IORefs under the hood, but provides a pure interface for it (an infinite tree). Because of this, you need to be a bit careful how you construct your supply when using multiple threads. The same techniques are used in GHC as well (for better or worse.) Note that the IDs you get are essentially non-deterministic -- they rely on evaluation order. I'm not sure why you need these uniques in the Show instances, though. Can't you just store the IDs with your data? [1]: http://hackage.haskell.org/package/value-supply On 5 March 2010 12:14, Robert Rothenberg rob...@gmail.com wrote: I'm implementing a variant of Prolog in Haskell (yes, I know others already exist...) and am looking to solve the following issues: (1) I need to translate anonymous variables _ into unique variable names. Data.Unique does not give me a printable identifier. Is there another package that does this? (2) Is there a cabal package similar to the Atom.hs module form ginsu, that associates strings with unique hashes? The alternative of course is to maintain state variables and pass them along to display and parsing functions, but that makes it difficult to make the terms instances of Read/Show without reference to a global variable anyhow. Thanks, Rob ___ 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] Re: Gut Build System
Matthias Kilian k...@outback.escape.de wrote: On Fri, Mar 05, 2010 at 09:26:08PM +, Simon Marlow wrote: Switching GHC to a completely new build system written completely in Haskell would be the most stupid idea ever. (You know why) You're referring to bootstrapping, I presume? Yes. As it stands, GHC can't be bootstrapped without a GHC, anyway. I'd love to see GHC bootstrapping from C, e.g. via hugs, though. (A man is allowed to dream) I did think about mentioning that. Of course any Haskell build system would have to support cross-compilation or some other bootstrapping method, e.g. generation of a build script. That's a noble goal. But it has to be kept in mind. This may be fairly easy, if the generated script does not have to come with major build-system capabilities: Leaving out most of dependency analysis and support -- at the utmost -- restarting a failed build from the rule whose source file has last recently changed, otherwise compiling in a linear order deduced at script generation time should reduce the problem to serializing the actions generated for a clean build to a shell script. I'm cross-posting this to the cafe and suggest that most if not all of this discussion be done there as most of it doesn't specifically relate to GHC. And there might be volunteers amidst the crowd. That said, I'd very much like to see a make-replacement done in Haskell, there's not only place for a properly-scriptable make, but also sufficient room for general innovation: Omake[1] would be even better if it wasn't scripted in some ad-hoc, impure, incomplete ocaml dialect but in a decently pure functional language; IBB[2] sound like a feature we'd definitely want to have (thanks for the link, Thomas) I'd also like to point to Nix[3] and Cabal[4] for ideas, and I bet most of the dependency analysis could be ripped from the latter. I think we can do vastly better than the whole SCons/CMake/Jam crowd. [1] http://omake.metaprl.org/index.html [2]http://chadaustin.me/2010/03/your-version-control-and-build-systems-dont-scale-introducing-ibb/ [3] http://nixos.org/nix/ [4] You know where. -- (c) this sig last receiving data processing entity. Inspect headers for copyright history. All rights reserved. Copying, hiring, renting, performance and/or quoting of this signature prohibited. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell platform for GHC 6.12.1?
Well the precompiled one provided on doesn't seem to work with GHC 6.12.1, you get an error. So yes, it would be nice to at least update the precompiled version on the website :-) On Thu, Mar 4, 2010 at 7:41 PM, Andrew Coppin andrewcop...@btinternet.com wrote: Peter Verswyvelen wrote: Using GHC 6.12.1 on Windows currently is hard, since one must compile the latest version of cabal-install, which is a nightmare to do for a typical windows user Out of curiosity, why do you need to compile the latest version of cabal-install? Why can't you use the precompiled one? ___ 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: Gut Build System
I'd also like to point to Nix[3] and Cabal[4] for ideas, and I bet most of the dependency analysis could be ripped from the latter. Hrrm, sadly Cabal has no dependency analysis at all - everything must be specified by the author of the .cabal file, both modules and packages. Regards, Malcolm ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Using Haskell's FFI to send ancillary data over Unix domain sockets
For me, this presents a few problems. I don't know where to get the SCM_CREDENTIALS constant, I have no idea what flags to use (does the Network module help with that?), I don't know how to get from a list of file descriptors or a tuple to a Ptr, and perhaps most importantly, I have no idea how to get the lengths of pid_t, uid_t, gid_t, and socklen_t. The basic answer is that you can use tools like hsc2hs, c2hs or greencard. I also wrote this package that may be of help: http://hackage.haskell.org/package/bindings-posix You may want to look at the source code to see how to apply the idea to your needs. Note that this package uses a lot of macros I wrote myself (see package bindings-DSL), so you should not use them if you want to stick with standard tools. Best, Maurício ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell platform for GHC 6.12.1?
Thomas Schilling wrote: GHC 6.12 changed the format of the internal package database. Only cabal-install 0.8 can read this format properly. Version 0.8 is only available on Hackage, the binaries available are cabal-install 0.6.2. I assume part of the platform release effort is to create new cabal-install binaries. Ah, OK. Just so long as there's a reason. :-) Is there a reason why a new precompiled binary can't be put up for download? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell platform for GHC 6.12.1?
Andrew Coppin andrewcop...@btinternet.com writes: Is there a reason why a new precompiled binary can't be put up for download? I would assume because no-one has supplied one (Duncan doesn't use Windows; don't know about the rest of the cabal-install developers). -- 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
Re: [Haskell-cafe] GPL answers from the SFLC (WAS: Re: ANN: hakyll-0.1)
Am Donnerstag, 4. März 2010 18:57:03 schrieb MightyByte: Interesting. It seems to me that the only solution for the BSD-oriented haskell community is to practically boycott GPL'd libraries. From what I understand, this is exactly what the LGPL is for. I've known the basic idea behind the GPL/LGPL distinction for quite awhile, but I didn't realize that mistaking the two had such far-ranging consequences. Since GPL seems to be the big elephant in the room, it seems very easy to make this mistake. At the very least we should try to educate the community about this. To my knowledge, the LGPL only allows *linking* with non-(L)GPL software. But GHC doesn’t just link but performs massive cross-module inlining. So in my opinion, LGPL is not a solution, too. Use BSD3! Best wishes, Wolfgang ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Gut Build System
Malcolm Wallace malcolm.wall...@cs.york.ac.uk wrote: I'd also like to point to Nix[3] and Cabal[4] for ideas, and I bet most of the dependency analysis could be ripped from the latter. Hrrm, sadly Cabal has no dependency analysis at all - everything must be specified by the author of the .cabal file, both modules and packages. ...with analysis I mean figuring out what needs to be done, with that data as the basis. You're right, of course. -- (c) this sig last receiving data processing entity. Inspect headers for copyright history. All rights reserved. Copying, hiring, renting, performance and/or quoting of this signature prohibited. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Gut Build System
malcolm.wallace: I'd also like to point to Nix[3] and Cabal[4] for ideas, and I bet most of the dependency analysis could be ripped from the latter. Hrrm, sadly Cabal has no dependency analysis at all - everything must be specified by the author of the .cabal file, both modules and packages. I could imagine a 'cabal inspect' command that checks the .cabal file against what the repo actually needs might be somewhat useful. -- Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: GPL answers from the SFLC (WAS: Re: ANN: hakyll-0.1)
To my knowledge, the LGPL only allows *linking* with non-(L)GPL software. But GHC doesn't just link but performs massive cross-module inlining. So in my opinion, LGPL is not a solution, too. Use BSD3! But that massive cross-module inlining happens at your computer, where the rights allowed by GPL for private use applies. So, as long as you distribute the GPL/LGPL code separate from your BSD/proprietary code, no restrictions should apply. (I believe this applies even with GPL, as all you'll be using in your code is the API which, as far as I know, can't be copyrighted, like any kind of interface -- even hardware interface. But I can't find a source on that.) Best, Maurício ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: GPL answers from the SFLC (WAS: Re: ANN: hakyll-0.1)
On Sat, 2010-03-06 at 00:28 +0100, Wolfgang Jeltsch wrote: Am Donnerstag, 4. März 2010 18:57:03 schrieb MightyByte: Interesting. It seems to me that the only solution for the BSD-oriented haskell community is to practically boycott GPL'd libraries. From what I understand, this is exactly what the LGPL is for. I've known the basic idea behind the GPL/LGPL distinction for quite awhile, but I didn't realize that mistaking the two had such far-ranging consequences. Since GPL seems to be the big elephant in the room, it seems very easy to make this mistake. At the very least we should try to educate the community about this. To my knowledge, the LGPL only allows *linking* with non-(L)GPL software. But GHC doesn’t just link but performs massive cross-module inlining. So in my opinion, LGPL is not a solution, too. Use BSD3! Best wishes, Wolfgang IANAL but it means you cannot distribute binaries using LGPL library compiled with GHC without providing sources as LGPL explicitly ask that the user have to have capability of relinking against new version of library. I.e.: - If you use other compiler which did not use massive cross-module inlining if is OK to use library. - If you publish sources - on any licence as long as the user can compile them against different version of library - it is OK (it does not have to be open source). It can have any ND licenses etc. you want. - If you prevent in any way the massive cross-module inlining then it is OK as well Regards PS. There is also GPL-with-linking-exception which allows linking etc. but does not require relinking capability. I'd believe that in such case the cross-module inlining is not a problem since it is 'linking' for compiler. signature.asc Description: This is a digitally signed message part ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Real-time garbage collection for Haskell
For settings we are using -N7 -A8m -qg. I don't know if they are really the optimal values but I haven't found a significant improvement on these yet. I tried -qb but that was slow. I tried larger values of A but that didn't seem to make a big difference. Also -N6 didn't make much difference. Specifying H values didn't seem to make much difference. I have to admit I don't fully understand the implications of the values and was just experimenting to see what worked best. Please let me know if there's anything you suggest I should try. That said, we have already got it to a speed where it's working so I'm ok with what we now. On Fri, Mar 5, 2010 at 9:38 PM, Simon Marlow marlo...@gmail.com wrote: What settings are you using, out of interest? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
