[Haskell-cafe] Haskell Weekly News: Issue 190
Welcome to issue 190 of the HWN, a newsletter covering developments in the Haskell community. This release covers the week of July 3 to 9, 2011. You can find the HTML version of this issue at: http://contemplatecode.blogspot.com/2011/07/haskell-weekly-news-issue-190.html Announcements Karel Gardas announced that he, Stephen Blackheath, and David Terei are "working together on ARM registerised port of GHC. The port is using LLVM as a code generator and in kind of working already." Testing is much appreciated! [1] http://goo.gl/TVvGD Matthias Fischmann inveted people to the HacPhi satellite in Berlin on July 29-31. See the post for details. Admission is free, but there is limited space, so don't wait too long! [2] http://goo.gl/XqdvI Quotes of the Week * chrisdone: [on hpaste as motivational tool] When I added hlint I was like 'hey Neil, check this', and he was all 'Oh noes! I must fix all the bugs!' * *amacleod started excising GOTOs from his BASIC code when he was 10. *roconnor started excising GOTOs from his Pascal code when he was 11. *luite used goto's in his C code last year. * AlanPerlis: One can't proceed from the informal to the formal by formal means. * Axman6: well, if C++ is anything to go by, the next Haskell will have lambdas and easy concurrency! * Cale: Constructing a definition from a type is formally the same thing as constructing a proof from a theorem. (Just with different logical systems in place :) * xplat: im in ur Sierpinski space, classifyin' ur subobjects * cmccann: in ContT, flow controls you * [Kron] What is the meaning of life? D: [joe6] learning agda? * camccann: Applying readFile to a file path doesn't return a String value any more than putting a steak next to a meat grinder magically turns them into a hamburger. * blackdog: the type system makes you strong, makes you hard. Top Reddit Stories * GHC on ARM Domain: ghcarm.wordpress.com, Score: 35, Comments: 4 On Reddit: [3] http://goo.gl/idJ7s Original: [4] http://goo.gl/D5zjE * The Monad.Reader Issue 18 Domain: themonadreader.wordpress.com, Score: 32, Comments: 3 On Reddit: [5] http://goo.gl/XA67w Original: [6] http://goo.gl/tzVX2 * Haskell vs. ML in the context of "Worse is Better" Domain: news.ycombinator.com, Score: 31, Comments: 25 On Reddit: [7] http://goo.gl/LpTbP Original: [8] http://goo.gl/bNU4w * Do (side) effects really need a total order? Domain: pchiusano.blogspot.com, Score: 31, Comments: 8 On Reddit: [9] http://goo.gl/jfxWl Original: [10] http://goo.gl/5tmUZ * Call for GUI examples - Any small GUI applications that you would like to see implemented with Functional Reactive Programming? Domain: apfelmus.nfshost.com, Score: 30, Comments: 13 On Reddit: [11] http://goo.gl/MMZJb Original: [12] http://goo.gl/X7IXP * Impredicative Polymorphism - A Use Case Domain: augustss.blogspot.com, Score: 23, Comments: 6 On Reddit: [13] http://goo.gl/QCwpt Original: [14] http://goo.gl/owsJT * Yesod :: Testimonials from a developer and designer Domain: yesodweb.com, Score: 19, Comments: 9 On Reddit: [15] http://goo.gl/5HOKo Original: [16] http://goo.gl/Zad2d * Parallelizing a nonogram solver Domain: jaspervdj.be, Score: 14, Comments: 2 On Reddit: [17] http://goo.gl/5LFlF Original: [18] http://goo.gl/BUbUA * A Haskell newbie's guide to Snap, Part 2 Domain: learnmeahaskell.blogspot.com, Score: 13, Comments: 0 On Reddit: [19] http://goo.gl/KTW50 Original: [20] http://goo.gl/rF1B1 * Losing my mind: Is Rhask (R language+Haskell) a real entity? Domain: self.haskell, Score: 11, Comments: 8 On Reddit: [21] http://goo.gl/O95KN Original: [22] http://goo.gl/O95KN Top StackOverflow Questions * How to gain control of a 5GB heap in Haskell? votes: 27, answers: 1 Read on SO: [23] http://goo.gl/OdZIG * Using higher-order Haskell types in C# votes: 16, answers: 2 Read on SO: [24] http://goo.gl/qzvok * Why applicative functors in Haskell and functional programming votes: 16, answers: 6 Read on SO: [25] http://goo.gl/72kE7 * Is there OS written in Haskell? votes: 16, answers: 3 Read on SO: [26] http://goo.gl/PgOeO * A good way to avoid “sharing”? votes: 15, answers: 1 Read on SO: [27] http://goo.gl/9GLzu * Hard Time Learning Haskell [migrated] votes: 13, answers: 0 Read on SO: [28] http://goo.gl/hhonY * Creating a Haskell REPL within a Haskell application votes: 11, answers: 1 Read on SO: [29] http://goo.gl/jZU7I About the Haskell Weekly News To help create new editions of this newsletter, please send stories to dstc...@gmail.com. Until next time, Daniel Santa Cruz References 1. http://permalink.gman
Re: [Haskell-cafe] [iteratee] empty chunk as special case of input
Sorry for the followup, but I forgot about one other important reason (probably the real reason) for the nullC case in bindIteratee. Note what happens in the regular case: the iteratee is run, and if it's in a completed state, the result is passed to the bound function (in the "m_done" line), which is then also run. Examine what happens if the inner iteratee is also complete: > const . flip onDone stream which would be more clearly written as > \b _str -> onDone b stream so in this case the leftover stream result from the first iteratee (stream) is used as the result of the second iteratee, and the leftover stream from the second iteratee (_str) is discarded. This doesn't seem right; what should happen is that the two streams should be appended somehow. It works because at this stage an iteratee won't have been enumerated over (by the current stream at least), so it can't have any leftover data, just a null chunk. But bindIteratee explicitly checks for the null chunk case also so that's not a problem. If the iteratee was enumerated over by another stream and therefore does have leftover data, then since that data isn't part of the current stream it's rightfully discarded anyway. This is why your function produced an unexpected result; it's in a completed state without having been enumerated over, but also has leftover data, which bindIteratee ignores. Now that I've thought about it, I'm not convinced this is always correct; in particular I suspect it for being responsible for a slightly convoluted implementation of enumFromCallbackCatch. I'll have to expend more brain cells on it, I think. John L. On Thu, Jul 14, 2011 at 1:15 AM, John Lato wrote: > Hi Sergey, > > iteratee (the package) uses a null chunk to signify that no further > stream data is available within the iteratee, that is, at some point > the stream has been entirely consumed. Therefore, if any of the > composed iteratees haven't run to completion, they need to get more > data from an enumerator. Thus 'bindIteratee' has the nullC guard in > the definition as an optimization; there's no need to send the null > chunk to bound iteratees because in most cases they won't be able to > do anything with it. > > I've recently considered removing this, but at present when I take it > out some unit tests fail and I haven't had time to explore further. > Since this would have other benefits I would like to do so provided it > doesn't strongly impact performance. Rather than simply removing the > case I could add a null case to the Stream type, but that could cause > some extra work for users. > > Also, one rule for writing iteratees is that they shouldn't put > elements into the stream. Doing so may cause various transformers to > behave incorrectly. If you want to modify a stream rather than simply > consuming elements, the correct approach is to create an enumeratee > (stream transformer). > > John L. > > On Wed, Jul 13, 2011 at 11:00 PM, Sergey Mironov wrote: >> Hi community, hi John. I find myself reading bindIteratee[1] function >> for a several days.. there is something that keeps me away from >> completely understanding of the concept. The most noticeble thing is >> \nullC\ guard in the definition. To demonstate the consequences of >> this solution, let me define an iterator like >> >> myI = Iteratee $ \onDone _ -> onDone 'a' (Chunk "xyz") >> >> It is a bit unusial, since myI substitutes real stream with a fake one >> (xyz). Now lets define two actions producing different results in >> unusual manner: >> >> printI i = enumPure1Chunk ['a'..'g'] i >>= run >>= print >> >> i1 = (return 'b' >> myI >> I.head) -- myI substitutes the stream, >> last /I.head/ produces 'x', OK >> i2 = (I.head >> myI >> I.head) -- produces 'b'! I expected another >> 'x' here but myI's stream was ignored by >>= >> >> Well, I understand that this is probably an expected behaviour, but >> what is it for? Why we can't handle null input like non-null? Iterator >> may just stay in it's current state in that case. >> >> Thanks in advance >> Sergey >> >> -- >> [1] - bindIteratee (basically, >>=) code from Data.Iteratee.Base.hs >> >> bindIteratee :: (Monad m, Nullable s) >> => Iteratee s m a >> -> (a -> Iteratee s m b) >> -> Iteratee s m b >> bindIteratee = self >> where >> self m f = Iteratee $ \onDone onCont -> >> let m_done a (Chunk s) >> | nullC s = runIter (f a) onDone onCont >> m_done a stream = runIter (f a) (const . flip onDone >> stream) f_cont >> where f_cont k Nothing = runIter (k stream) onDone onCont >> f_cont k e = onCont k e >> in runIter m m_done (onCont . (flip self f .)) >> > ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] [iteratee] empty chunk as special case of input
Hi Sergey, iteratee (the package) uses a null chunk to signify that no further stream data is available within the iteratee, that is, at some point the stream has been entirely consumed. Therefore, if any of the composed iteratees haven't run to completion, they need to get more data from an enumerator. Thus 'bindIteratee' has the nullC guard in the definition as an optimization; there's no need to send the null chunk to bound iteratees because in most cases they won't be able to do anything with it. I've recently considered removing this, but at present when I take it out some unit tests fail and I haven't had time to explore further. Since this would have other benefits I would like to do so provided it doesn't strongly impact performance. Rather than simply removing the case I could add a null case to the Stream type, but that could cause some extra work for users. Also, one rule for writing iteratees is that they shouldn't put elements into the stream. Doing so may cause various transformers to behave incorrectly. If you want to modify a stream rather than simply consuming elements, the correct approach is to create an enumeratee (stream transformer). John L. On Wed, Jul 13, 2011 at 11:00 PM, Sergey Mironov wrote: > Hi community, hi John. I find myself reading bindIteratee[1] function > for a several days.. there is something that keeps me away from > completely understanding of the concept. The most noticeble thing is > \nullC\ guard in the definition. To demonstate the consequences of > this solution, let me define an iterator like > > myI = Iteratee $ \onDone _ -> onDone 'a' (Chunk "xyz") > > It is a bit unusial, since myI substitutes real stream with a fake one > (xyz). Now lets define two actions producing different results in > unusual manner: > > printI i = enumPure1Chunk ['a'..'g'] i >>= run >>= print > > i1 = (return 'b' >> myI >> I.head) -- myI substitutes the stream, > last /I.head/ produces 'x', OK > i2 = (I.head >> myI >> I.head) -- produces 'b'! I expected another > 'x' here but myI's stream was ignored by >>= > > Well, I understand that this is probably an expected behaviour, but > what is it for? Why we can't handle null input like non-null? Iterator > may just stay in it's current state in that case. > > Thanks in advance > Sergey > > -- > [1] - bindIteratee (basically, >>=) code from Data.Iteratee.Base.hs > > bindIteratee :: (Monad m, Nullable s) > => Iteratee s m a > -> (a -> Iteratee s m b) > -> Iteratee s m b > bindIteratee = self > where > self m f = Iteratee $ \onDone onCont -> > let m_done a (Chunk s) > | nullC s = runIter (f a) onDone onCont > m_done a stream = runIter (f a) (const . flip onDone > stream) f_cont > where f_cont k Nothing = runIter (k stream) onDone onCont > f_cont k e = onCont k e > in runIter m m_done (onCont . (flip self f .)) > ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ANN: fix-imports-0.1.2
On Wed, Jul 13, 2011 at 3:05 PM, Markus Läll wrote: > One thing that to look out for though is that it first checks for > modules from the current directory down -- so running it in somewhere > you happen to have ghc sources too, will have all that come with it > imported from there (and lines like "import path.to.ghc.DataMaybe > (fromJust)" added). But this probably happens only when testing the > program in the root of your home directory... Yeah, currently the most annoying thing is when it guesses wrong. It's set up to work with my project, but you can tweak the search heuristic easily enough by editing findLocalModule. I'll have it skip non-capitalized directories, but a better solution is to not edit modules in your home directory :) > (The reason I'm not using it regularly is that I haven't figured out a > good way to use it, when developing with Notepad++ over sftp in > another environment) Well, if anyone makes bindings for other editors, feel free to send a patch. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ANN: fix-imports-0.1.2
I have used it a little and it worked quite nicely. One thing that to look out for though is that it first checks for modules from the current directory down -- so running it in somewhere you happen to have ghc sources too, will have all that come with it imported from there (and lines like "import path.to.ghc.DataMaybe (fromJust)" added). But this probably happens only when testing the program in the root of your home directory... (The reason I'm not using it regularly is that I haven't figured out a good way to use it, when developing with Notepad++ over sftp in another environment) -- Markus Läll ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] [iteratee] empty chunk as special case of input
Hi community, hi John. I find myself reading bindIteratee[1] function for a several days.. there is something that keeps me away from completely understanding of the concept. The most noticeble thing is \nullC\ guard in the definition. To demonstate the consequences of this solution, let me define an iterator like myI = Iteratee $ \onDone _ -> onDone 'a' (Chunk "xyz") It is a bit unusial, since myI substitutes real stream with a fake one (xyz). Now lets define two actions producing different results in unusual manner: printI i = enumPure1Chunk ['a'..'g'] i >>= run >>= print i1 = (return 'b' >> myI >> I.head) -- myI substitutes the stream, last /I.head/ produces 'x', OK i2 = (I.head >> myI >> I.head) -- produces 'b'! I expected another 'x' here but myI's stream was ignored by >>= Well, I understand that this is probably an expected behaviour, but what is it for? Why we can't handle null input like non-null? Iterator may just stay in it's current state in that case. Thanks in advance Sergey -- [1] - bindIteratee (basically, >>=) code from Data.Iteratee.Base.hs bindIteratee :: (Monad m, Nullable s) => Iteratee s m a -> (a -> Iteratee s m b) -> Iteratee s m b bindIteratee = self where self m f = Iteratee $ \onDone onCont -> let m_done a (Chunk s) | nullC s = runIter (f a) onDone onCont m_done a stream = runIter (f a) (const . flip onDone stream) f_cont where f_cont k Nothing = runIter (k stream) onDone onCont f_cont k e = onCont k e in runIter m m_done (onCont . (flip self f .)) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Paid work available in functional web programming
Christopher Done wrote: I also find it hard to understand the type system in a non-superficial level because the related paper was very hard to grok. I'll only claim it's a fairly breezy read for people familiar with dependent type theory, which admittedly is not a huge crowd, even as a proportion of the Haskell community. More accessible documentation of that aspect is on my to-do list. I'm more or less waiting to start it until I get this current commercial project staffed properly. I know it _is_ possible to learn the interesting type system features well enough with just the existing documentation, because one programmer on the project, who has no CS research background, has managed to do it without much apparent trouble. I tried to get it running a while ago and could not get it to compile. You couldn't get the compiler to compile? No one has reported problems recently, so I suspect everything would Just Work today, if you're using Linux or OS X (and possibly in other cases). I would also like to see how it handles non-web stuff as inevitably IME web applications involve more than merely reading and writing to a database. I have no near-term plans to build an Ur implementation that handles non-web applications. There is an FFI, though. Yves_Pares wrote: It'd also be interesting to know what you missed in Haskell web development so that you needed to build a new language inspired from it. The key piece is precisely the basis of my paper "Ur: Statically-Typed Metaprogramming with Type-Level Record Computation." Haskell is missing the features that I think are critical for pleasant type-level computation, in particular of the variety that I use in the examples detailed in the paper. I'll leave the rest of my argument to be read out of the paper by those with enough background to do so. Folks without that background might at least read the case studies part of the paper and consider how such things might be implemented in Haskell, with equivalent or stronger static guarantees. Ertugrul Soeylemez wrote: Christopher Done wrote: > > I write to mention briefly that I'm looking for people interested in > > writing Ur/Web programs for pay. Ur/Web is a DSL for building > > modern web applications, and I believe it is truly a secret weapon > > for that domain, and one that should appeal to many Haskell fans. I > > have one customer now for whom I'm leading a project to develop a > > particular web application, and I'd like to have more. The current > > project would benefit from more programming help, and I would also > > like to develop a network of people interested in future projects. > > I would like to see a real application in Ur/Web. There are many > simple examples. I don't and wouldn't want to develop like that, > writing raw HTML and SQL seems going backwards despite the incredible > advances in consistency and correctness that Ur/Web offers. I agree about the HTML part, but not so much about the SQL part. Personally I went back from all the nice abstractions to writing raw SQL, because I realized that this is the only way to really exploit the power of my database system (PostgreSQL) [1]. I agree. I find that SQL is the most natural language for expressing data reading and writing, at least for the web applications I write. The need to go through a less declarative interface (e.g., classic ORMs) would be a bug, not a feature, for me. (Though the online Ur/Web demos include type-safe ORM implemented as a library completely within the language!) As far as HTML templating goes, templates are easy to implement as functions within Ur. I understand that people unfamiliar with the language will want to see code examples before accepting this, but unfortunately I have none now. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ANN: fix-imports-0.1.2
On Wed, Jul 13, 2011 at 12:08 PM, Henning Thielemann wrote: > I also spend some time on managing imports. I'll try this program. However, > usually I have a mix of qualified and unqualified imports, since some > libraries are designed for unqualified imports. You can still use unqualified imports, it just won't manage those for you. Automatically managing unqualified imports is solvable but harder. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ANN: fix-imports-0.1.2
On 12.07.2011 09:59, Evan Laforge wrote: I meant more in the "Before: ... After: ..." sense ;-) (i.e. visually being able to tell what your program does, rather than just a description). Oh, ok, I guess I can do that too: Before: module M where import ZZ.Out.Of.Order import qualified No.Longer.Needed as Needed -- x = Needed.y -- just removed this y = New.something -- just added this After: module M where import qualified Heavily.Nested.New as New import ZZ.Out.Of.Order -- x = Needed.y -- just removed this y = New.something -- just added this I also spend some time on managing imports. I'll try this program. However, usually I have a mix of qualified and unqualified imports, since some libraries are designed for unqualified imports. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Paid work available in functional web programming
Christopher Done wrote: > > I write to mention briefly that I'm looking for people interested in > > writing Ur/Web programs for pay. Ur/Web is a DSL for building > > modern web applications, and I believe it is truly a secret weapon > > for that domain, and one that should appeal to many Haskell fans. I > > have one customer now for whom I'm leading a project to develop a > > particular web application, and I'd like to have more. The current > > project would benefit from more programming help, and I would also > > like to develop a network of people interested in future projects. > > I would like to see a real application in Ur/Web. There are many > simple examples. I don't and wouldn't want to develop like that, > writing raw HTML and SQL seems going backwards despite the incredible > advances in consistency and correctness that Ur/Web offers. I agree about the HTML part, but not so much about the SQL part. Personally I went back from all the nice abstractions to writing raw SQL, because I realized that this is the only way to really exploit the power of my database system (PostgreSQL) [1]. [1] http://coder.mx/journal/yesod-persistent-vs-sql > I also find it hard to understand the type system in a non-superficial > level because the related paper was very hard to grok. I tried to get > it running a while ago and could not get it to compile. I would also > like to see how it handles non-web stuff as inevitably IME web > applications involve more than merely reading and writing to a > database. > > I like the idea, please keep us posted about it. I like the continuation part about it. If there were a web framework in Haskell similar to the continuation-based framework in Racket or Ur/Web, I would most certainly switch to it (from Yesod), given that it's mature enough. Greets, Ertugrul -- nightmare = unsafePerformIO (getWrongWife >>= sex) http://ertes.de/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Splitting Hackage Packages and re-exporting entire modules (with same module name)
On Wed, Jul 13, 2011 at 10:31 AM, Bertram Felgenhauer
wrote:
> Antoine Latter wrote:
>> If you give the module a new name in the new package then the old
>> module can re-export all of the symbols in the new module.
>>
>> In GHC I don't think there is a way for two packages to export the
>> same module and have them be recognized as the same thing, as far as I
>> know.
>
> Right, but you don't have to rename the module if you use the
> PackageImports extension. (Incidentally, this used by the haskell2010
> ibrary, which is implemented in terms of base)
>
> http://haskell.org/ghc/docs/latest/html/users_guide/syntax-extns.html#package-imports
>
> So the following should work, assuming 'original' is a package exporting
> the Foo.Bar module.
>
> {-# LANGUAGE PackageImports #-}
> module Foo.Bar (module Original) where
>
> import "original" Foo.Bar as Original
>
> Best regards,
>
> Bertram
>
The downside to this approach is that anyone trying to use the module
in GHCi (or use the module in a non-Cabal setting) will need to
manually hide one of the packages.
Does anyone know if there is a way to make Cabal auto-hide a package
after install without too much trickery? That might be more than you
want to do.
Antoine
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>
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Re: [Haskell-cafe] Paid work available in functional web programming
I also think it would be really good to have some documentation that explains the type system and how to do neat things with it in terms that a reasonably competent haskell / ML programmer could understand. I played around with Ur/Web about a year ago and was able to make a simple application, and use some C libraries (the C FFI is really easy to use), but realized that I wasn't able to do much of anything beyond mimicking the demos in various ways, mainly because the documentation was so sparse (when I didn't know how to do something, I just tried to do what I would expect it to do if it were haskell, which worked a surprising amount of the time, but wasn't the most enjoyable experience). Looking at, for example, page 19 of the reference manual [1], which is supposed to explain how expressions are typed (which I would assume would give input into how the type system worked), I, probably like Chris, couldn't make much sense of it. Now I don't have a PhD in type theory, or even a masters degree, but if your intended audience includes people like me, the documentation definitely needs work! Now perhaps understanding those tables isn't actually important to using the language, but from looking through the manual / available documentation, there seems to be the really basic cookbook style stuff, that you can copy and paste and modify, as long as you are careful, then the source code itself, from which more can be gleaned, and then this type of type theory. Because of this (or until there is real documentation explaining some of the novel things about this language), I think Ur/Web is going to remain a cool thing that barely anyone can do anything with. Something to be linked in reddit or stack overflow posts, but not actually used! It seems like documentation of the really basic stuff is there, and the really advanced stuff (which is great, don't get me wrong), but the stuff in the middle is missing! Which is too bad, because it seems like it is doing some really exciting things. 1. http://www.impredicative.com/ur/manual.pdf On Jul 13, 2011, at 11:10 AM, Christopher Done wrote: > On 13 July 2011 15:28, Adam Chlipala wrote: >> I write to mention briefly that I'm looking for people interested in writing >> Ur/Web programs for pay. Ur/Web is a DSL for building modern web >> applications, and I believe it is truly a secret weapon for that domain, and >> one that should appeal to many Haskell fans. I have one customer now for >> whom I'm leading a project to develop a particular web application, and I'd >> like to have more. The current project would benefit from more programming >> help, and I would also like to develop a network of people interested in >> future projects. >> >> More information on Ur/Web can be found here: >>http://www.impredicative.com/ur/ > > I would like to see a real application in Ur/Web. There are many > simple examples. I don't and wouldn't want to develop like that, > writing raw HTML and SQL seems going backwards despite the incredible > advances in consistency and correctness that Ur/Web offers. I also > find it hard to understand the type system in a non-superficial level > because the related paper was very hard to grok. I tried to get it > running a while ago and could not get it to compile. I would also like > to see how it handles non-web stuff as inevitably IME web applications > involve more than merely reading and writing to a database. > > I like the idea, please keep us posted about it. > > ___ > 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] Splitting Hackage Packages and re-exporting entire modules (with same module name)
Antoine Latter wrote:
> If you give the module a new name in the new package then the old
> module can re-export all of the symbols in the new module.
>
> In GHC I don't think there is a way for two packages to export the
> same module and have them be recognized as the same thing, as far as I
> know.
Right, but you don't have to rename the module if you use the
PackageImports extension. (Incidentally, this used by the haskell2010
ibrary, which is implemented in terms of base)
http://haskell.org/ghc/docs/latest/html/users_guide/syntax-extns.html#package-imports
So the following should work, assuming 'original' is a package exporting
the Foo.Bar module.
{-# LANGUAGE PackageImports #-}
module Foo.Bar (module Original) where
import "original" Foo.Bar as Original
Best regards,
Bertram
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Re: [Haskell-cafe] Paid work available in functional web programming
It'd also be interesting to know what you missed in Haskell web development so that you needed to build a new language inspired from it. 2011/7/13 Christopher Done > On 13 July 2011 15:28, Adam Chlipala wrote: > > I write to mention briefly that I'm looking for people interested in > writing > > Ur/Web programs for pay. Ur/Web is a DSL for building modern web > > applications, and I believe it is truly a secret weapon for that domain, > and > > one that should appeal to many Haskell fans. I have one customer now for > > whom I'm leading a project to develop a particular web application, and > I'd > > like to have more. The current project would benefit from more > programming > > help, and I would also like to develop a network of people interested in > > future projects. > > > > More information on Ur/Web can be found here: > >http://www.impredicative.com/ur/ > > I would like to see a real application in Ur/Web. There are many > simple examples. I don't and wouldn't want to develop like that, > writing raw HTML and SQL seems going backwards despite the incredible > advances in consistency and correctness that Ur/Web offers. I also > find it hard to understand the type system in a non-superficial level > because the related paper was very hard to grok. I tried to get it > running a while ago and could not get it to compile. I would also like > to see how it handles non-web stuff as inevitably IME web applications > involve more than merely reading and writing to a database. > > I like the idea, please keep us posted about it. > > ___ > 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] Paid work available in functional web programming
On 13 July 2011 15:28, Adam Chlipala wrote: > I write to mention briefly that I'm looking for people interested in writing > Ur/Web programs for pay. Ur/Web is a DSL for building modern web > applications, and I believe it is truly a secret weapon for that domain, and > one that should appeal to many Haskell fans. I have one customer now for > whom I'm leading a project to develop a particular web application, and I'd > like to have more. The current project would benefit from more programming > help, and I would also like to develop a network of people interested in > future projects. > > More information on Ur/Web can be found here: > http://www.impredicative.com/ur/ I would like to see a real application in Ur/Web. There are many simple examples. I don't and wouldn't want to develop like that, writing raw HTML and SQL seems going backwards despite the incredible advances in consistency and correctness that Ur/Web offers. I also find it hard to understand the type system in a non-superficial level because the related paper was very hard to grok. I tried to get it running a while ago and could not get it to compile. I would also like to see how it handles non-web stuff as inevitably IME web applications involve more than merely reading and writing to a database. I like the idea, please keep us posted about it. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Seeking Don Stewart
Hi everyone, I'm working for Standard Chartered, based in New York (currently though, I'm in Singapore). You can reach me on this email. Cheers, Don On Wed, Jul 13, 2011 at 5:09 PM, wren ng thornton wrote: > Hello all, > > Sorry for the spam. I'm trying to get ahold of Don Stewart, but it looks > like there's some hiccup at Galois. When I mail him I get: > > : host mail.galois.com[69.30.63.196] said: 550 5.1.1 > ... User unknown (in reply to RCPT TO command) > > Does anyone know what's up, or if there's another (non-emergency) way to > get in touch with him? > > -- > Live well, > ~wren > > > > ___ > 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] Paid work available in functional web programming
First, I apologize in advance if this post is deemed off-topic. It's about Ur/Web, a statically typed, pure functional programming languages that is much influenced by Haskell. For instance, Ur/Web includes monadic IO and type classes. I write to mention briefly that I'm looking for people interested in writing Ur/Web programs for pay. Ur/Web is a DSL for building modern web applications, and I believe it is truly a secret weapon for that domain, and one that should appeal to many Haskell fans. I have one customer now for whom I'm leading a project to develop a particular web application, and I'd like to have more. The current project would benefit from more programming help, and I would also like to develop a network of people interested in future projects. More information on Ur/Web can be found here: http://www.impredicative.com/ur/ So, are you interested in being paid at least market rates to develop real web applications in a cool Haskell-like language, thus helping to push functional programming further into the real world? Might you have any leads for possible customers for this kind of work, possibly including start-ups that want to do in-house development using a cool language with close support from the language creator (which happens to be me!)? I would love to receive reply e-mails with positive answers to either question! ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Baffling Hackage build log
> This seems to be a general problem with the Hackage server as other > packages uploaded after yours have failed to build with similar > errors... It seems one batch of builds was broken due to some failure in downloading the package index. I've re-run it. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Seeking Don Stewart
wren ng thornton wrote: > Hello all, > > Sorry for the spam. I'm trying to get ahold of Don Stewart, but it looks > like there's some hiccup at Galois. When I mail him I get: > > : host mail.galois.com[69.30.63.196] said: 550 5.1.1 > ... User unknown (in reply to RCPT TO command) Don recently left Galois and is now working for a bank in NYC. Find him on google+. Erik -- -- Erik de Castro Lopo http://www.mega-nerd.com/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Seeking Don Stewart
Don isn't working at Galois anymore. I guess his new email address is simple to find but I gave it to Wren privately. But I guess the sloth signal works fine too. Cheers, Thu 2011/7/13 Yves Parès : > It's mine too! > Who!? Who said that? Links! I want links! (And names) > > 2011/7/13 Michael Snoyman >> >> Just post something on Stack Overflow, throw in a line about how >> inefficient Haskell is compared with Java. It's like his bat signal. >> >> Michael >> >> On Wed, Jul 13, 2011 at 12:09 PM, wren ng thornton >> wrote: >> > Hello all, >> > >> > Sorry for the spam. I'm trying to get ahold of Don Stewart, but it looks >> > like there's some hiccup at Galois. When I mail him I get: >> > >> > : host mail.galois.com[69.30.63.196] said: 550 5.1.1 >> > ... User unknown (in reply to RCPT TO command) >> > >> > Does anyone know what's up, or if there's another (non-emergency) way to >> > get in touch with him? >> > >> > -- >> > Live well, >> > ~wren >> > >> > >> > >> > ___ >> > 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] Seeking Don Stewart
It's mine too! Who!? Who said that? Links! I want links! (And names) 2011/7/13 Michael Snoyman > Just post something on Stack Overflow, throw in a line about how > inefficient Haskell is compared with Java. It's like his bat signal. > > Michael > > On Wed, Jul 13, 2011 at 12:09 PM, wren ng thornton > wrote: > > Hello all, > > > > Sorry for the spam. I'm trying to get ahold of Don Stewart, but it looks > > like there's some hiccup at Galois. When I mail him I get: > > > > : host mail.galois.com[69.30.63.196] said: 550 5.1.1 > > ... User unknown (in reply to RCPT TO command) > > > > Does anyone know what's up, or if there's another (non-emergency) way to > > get in touch with him? > > > > -- > > Live well, > > ~wren > > > > > > > > ___ > > 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] Seeking Don Stewart
Just post something on Stack Overflow, throw in a line about how inefficient Haskell is compared with Java. It's like his bat signal. Michael On Wed, Jul 13, 2011 at 12:09 PM, wren ng thornton wrote: > Hello all, > > Sorry for the spam. I'm trying to get ahold of Don Stewart, but it looks > like there's some hiccup at Galois. When I mail him I get: > > : host mail.galois.com[69.30.63.196] said: 550 5.1.1 > ... User unknown (in reply to RCPT TO command) > > Does anyone know what's up, or if there's another (non-emergency) way to > get in touch with him? > > -- > Live well, > ~wren > > > > ___ > 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] Seeking Don Stewart
Hello all, Sorry for the spam. I'm trying to get ahold of Don Stewart, but it looks like there's some hiccup at Galois. When I mail him I get: : host mail.galois.com[69.30.63.196] said: 550 5.1.1 ... User unknown (in reply to RCPT TO command) Does anyone know what's up, or if there's another (non-emergency) way to get in touch with him? -- Live well, ~wren ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
