- Libraries - Haskell.org

wither the Platform
by Mark Lentczner 29 Mar '15

29 Mar '15

I'm wondering how we are all feeling about the platform these days.... I notice that in the new Haskell pages, the Platform is definitely not the recommended way to go: The main download pages suggests the compiler and base libraries as the first option - and the text for the Platform (second option) pretty much steers folks away from it. Of the per-OS download pages, only the Windows version even mentions it. Does this mean that we don't want to consider continuing with it? It is a lot of community effort to put out a Platform release - we shouldn't do it if we don't really want it. That said, I note that the other ways to "officially get" Haskell look, to my eye, very ad hoc. Many of the options involve multiple steps, and exactly what one is getting isn't clear. It hardly looks like there is now an "official, correct" way to setup Haskell. The Platform arose in an era before sandboxes and before curated library sets like Stackage and LTS. Last time we set direction was several years ago. These new features and development have clearly changed the landscape for use to reconsider what to do. I don't think the status quo for the Platform is now viable - mostly as evidenced by waning interest in maintaining it. I offer several ways we could proceed: *1) Abandon the Platform.* GHC is release in source and binary form. Other package various installers, with more or less things, for various OSes. *2) Slim the Platform.* Pare it back to GHC + base + a smaller set of "essential" libs + tools. Keeps a consistent build layout and installation mechanism for Haskell. *3) Re-conceive the Platform.* Take a very minimal install approach, coupled with close integration with a curated library set that makes it easy to have a rich canonical, stable environment. This was the core idea around my "GPS Haskell" thoughts from last September - but there would be much to work out in this direction. Thoughts? — Mark

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GHC 7.10.1 bindist for OS X + Haskell Platform 2015.2.0.0 Alpha 2
by Mark Lentczner 28 Mar '15

28 Mar '15

I have built the 7.10.1 bindist for OS X. It is currently sitting on my server at: ghc-7.10.1-x86_64-apple-darwin.tar.bz2 <http://www.ozonehouse.com/mark/platform/ghc-7.10.1-x86_64-apple-darwin.tar.…> \O/ I have built an Alpha 2 of Haskell Platform 2015.2.0.0 for OS X <http://www.ozonehouse.com/mark/platform/Haskell%20Platform%202015.2.0.0%20a…>. It is based on the above bindist. I should have an ubuntu version of the Platform built by tomorrow. \O/ - Mark *sha256 sums:* c6eb8d573538eba27dfb2d9acf52a1beaaa512208261528b91e8d1775d133eee ghc-7.10.1-x86_64-apple-darwin.tar.bz2 0cb351281fcf5ef34c54b455a3643d0ff078299a53b2c39d911dbda4aac2d233 Haskell Platform 2015.2.0.0 alpha 2 64bit.pkg

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Re: HP 2015.2.0.0 and GHC 7.10
by Mark Lentczner 28 Mar '15

28 Mar '15

*Hey you....* yes you... Platform committee member, or Platform library maintainer, Platform packager... that's right, you: GHC 7.10 is about to be released. Wouldn't it rock if we came out with a Platform within days? Or on the same day? I know, I know, our process is long and full of discussion, and hard, and slow.... let's smash that, eh? How'z'bout it? OKAY? Good! Your task is: - look over the the source file at GitHub <https://github.com/haskell/haskell-platform/blob/pre-release/hptool/src/Rel…> that defines the release - see if the version of your stuff looks right - yeah, I bumped it all to latest, major or minor version change - so APIs probably broke from last HP - look near the end where there is a bunch of stuff I kinda just added to get it all to compile - read the notes about those things in the first message of this thread (copied below) - weigh in - short and sweet - if you have an opinion - if you have a spare Mac - download it and try it! <http://www.ozonehouse.com/mark/platform/> Crazy, right? I know... but, can we do this? — Mark On Sun, Mar 22, 2015 at 10:13 PM, Mark Lentczner <mark.lentczner(a)gmail.com> wrote: > I've gone ahead and built a very provisional, alpha version of 2015.2.0.0 > using GHC 7.10 RC3. > > I bumped all the GHC libs to the versions in 7.10, and bumped all the > Platform libs to the latest versions I could find on Hackage. There were a > few issues: > > - *old-locale and old-time* - no longer part of GHC, but > cabal-install, cgi & HTTP need them - and they are part of the platform - > so included now as added packages. Not sure this is a great idea, since > they are now very deprecated... but until cabal-install, cgi, & HTTP > update, not sure what else to do. > - *tf-random* - is now required by alex and QuickCheck - seems a shame > to add this, as now we're going to have two random packages > - *network-uri *- was split out of network, and needed by > cabal-install, cgi, & HTTP. I suppose we should include it, as it was > functionality and API that was part of the platform > - *exceptions* & *multipart* - needed by cgi - is exceptions now > subsumed by something in transformers? and... multipart? maybe time to drop > cgi? We didn't have it last time anyway as it wouldn't compile! > - *scientific* - needed by attoparsec - debated in detail last time > ... and we're still here! > > The Platform is significantly larger now: On OS X it has gone from 316M to > 499M! Most of this is due to new OpenGL libs which are now huge (went from > 98M to 239M!) GHC itself grew by 109M (to almost 1G), so that the whole > installed magilla is 1.5G! Even the compressed installer is now 250M! > > If you want to poke at it, the source is in the pre-release branch at > GitHub <https://github.com/haskell/haskell-platform/tree/pre-release>, > and the OS X builds are at my usual platform staging area: > > Index of /mark/platform <http://www.ozonehouse.com/mark/platform/> > > > Remember, it already includes GHC, so no need to download the GHC binary > for OS X that is there, too. > > I'll try to get a generic linux build up soonish... but my VM now runs out > of memory trying to build OpenGL - and adding more only makes my machine > thrash to death! > > - Mark > >

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Re: [Haskell-cafe] ListT considered harmful
by Chris Wong 27 Mar '15

27 Mar '15

On Fri, Mar 27, 2015 at 5:07 PM, Michael Snoyman <michael(a)snoyman.com> wrote: > I'm in favor of deprecation, but opposed to removing any time soon due to > backwards compatibility concerns. I agree. Given that we just deprecated ErrorT (which is both more popular, and does follow the monad laws) I think there is good reason to phase out transformers' ListT as well. I've attached a patch that adds the relevant pragma. I'm not familiar with darcs so excuse me if it's messed up :) libraries list and/or Ross Paterson, do you have anything to say about this issue? > On Fri, Mar 27, 2015 at 7:03 AM Fumiaki Kinoshita <fumiexcel(a)gmail.com> > wrote: >> >> It is well known that ListT m in transformers is not a monad unless the >> underlying monad is commutative. The fact that ListT is not a monad >> transformer is sufficient to remove it from the package, and several >> packages already defined their own ListT. >> >> Oughtn't we deprecate ListT or replace it by a correct one? >> _______________________________________________ >> Haskell-Cafe mailing list >> Haskell-Cafe(a)haskell.org >> http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe > > > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe(a)haskell.org > http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe > -- Chris Wong https://lambda.xyz

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ansi-wl-pprint
by Edward Kmett 26 Mar '15

26 Mar '15

ansi-wl-pprint sits underneath a large chunk of our infrastructure: test-framework, criterion, trifecta, etc. Transitively through those dependencies it affects a very large percentage of the Haskell packages we have today, because you can't build almost anybody's testing and benchmarking frameworks without it. We recently had to push out an non-maintainer update for GHC 7.10-rc3 compatibility, and due to NMU update guidelines meant we had to wait 2 weeks before we could do anything. This pretty much ensured that the entire 7.10-rc3 release cycle went by with very very few people able to run their test suites, and little testing was able to be performed in the allotted window. Fortunately, Neil managed to find a rather large regression on his own during this time: http://neilmitchell.blogspot.com/2015/03/finding-ghc-bug.html That said, given that we found issues with linear caused by the changes to Typeable, once we fixed the test suite, this gives me pause. I'm pretty sure nobody downstream of linear tried to run their test suites on rc3. I'd like to not find ourselves in that situation again. We have a policy of considering requests for maintainership transfer after ~6 months of inactivity. Max has been inactive for over a year. I'd like to invoke that today, and formally request to take over maintainership of ansi-wl-pprint. All of the visible activity on https://github.com/batterseapower in the last year or so is on java projects. We've already adopted test-framework. In the event Max returns to active status in the Haskell community, I'd happily relinquish control. Thank you for your consideration, -Edward

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quick report using GHC 7.10 RC3
by Mark Lentczner 26 Mar '15

26 Mar '15

I built up a provisional HP 2015.2.0.0 based on GHC 7.10 RC3, and then when testing it, built my medium-ish project Plush with it all. This is my first brush with 7.10 and the new base libs, Applicative, FTP and all. For the most part, it all worked, but here are some observations: *1. Cabal-1.22.1.2 isn't on Hackage* Boot strapping HP now needs to bootstrap cabal-install in order to be able to build with 7.10. My fancy-pants build system for HP doesn't do that (yet), so I did it by hand. Only hitch: Cabal 1.22.1.2 isn't on hackage, so I had to build with 1.22.1.1 - so the bootstrap wasn't perfect, but good enough to work. *2. Still need old-local and old-time* Because....wait for it... cabal-install needs them! So do cgi and HTTP packages. *3. Slower compilation* The platform used to take about 20min. to compile. Now it takes a full hour. Did GHC really slow down that much? The newer OpenGL and OpenGLRaw packages are significantly larger and slower, and that might account for about half the extra time... but still GHC seems much slower. *4. GHC is a disk monster* Now weighing in at 900+MB! That is 100MB over 7.8! *5. Warnings Galore* Of course most of the packages compile with tons of warnings. I mean tons! Looking at my own packages, since I usually compile -Wall, I will need tons of work to remove these. The saddness is that if I want my package to continue to work on 7.8 I'll have to put in tons of CPP statements. *6. Bit by additions to the Prelude* In particular, Word, since I had a data type named that. (It was in a grammar for the shell, and since Data.Word was no where near this, I claim it was a reasonable choice of name.) I had to add tons of import Prelude hiding (Word) statements. Adding common words as new exports from the Prelude is a real pain! *7. Cabal incompatible API change* In particular, the api that a custom Setup.hs uses. Distribution.Simple.UserHooks changed the type of a hook. It should not, it should have added another to do what it wanted. The poblem is you can't use CPP in Setup.hs. And so now anyone using the testHook hook is in a pickle: Your Setup.hs can't work in both 7.10 and 7.8! *8. Haddock messaging* What has gotten into Haddock? There is so much terminal output now - I just have to ignore it all. It spews more than the compiler does. *9. Library divergence* We have random... and now we'll have to have tf-random, too, because alex and QuickCheck both need it. So now we'll have two random libraries. Couldn't we have folded tf-random into random? On a similar front, we've got attoparsec, pulling in scientific. Couldn't that have gone somewhere? I realize that the trend is for many small minimal libs... but for the core that is going to all be there always anyway - and more closed set works better I think. Summary: 1, 2 & 8 are minor, 3 & 4 are sad. 5 ~ 7 will make the job of anyone who wants their code to work with even one prior major GHC rev. hard, and ugly. 9 is what makes me worry most... — Mark

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Generalize filterM to Applicative
by David Feuer 25 Mar '15

25 Mar '15

Currently, filterM :: (Monad m) => (a -> m Bool) -> [a] -> m [a] filterM p = foldr go (return []) where go x r = do flg <- p x ys <- r return (if flg then x:ys else ys) We could change this to filterM :: (Applicative f) => (a -> f Bool) -> [a] -> f [a] filterM p = foldr go (pure []) where go x r = f <$> p x <*> r where f flg ys = if flg then x:ys else ys

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TLS Support
by Dominic Steinitz 25 Mar '15

25 Mar '15

I don’t often venture an opinion here but I would be very much *against* using OpenSSL given the number of vulnerabilities it continues to experience. There’s http://www.mitls.org/wsgi/home which has been formally verified and our own https://hackage.haskell.org/package/tls. Dominic Steinitz dominic(a)steinitz.org http://idontgetoutmuch.wordpress.com On 25 Mar 2015, at 09:08, libraries-request(a)haskell.org wrote: > Also, to this day we don't have any TLS library support in the platform, > which also is subject to debate of which crypto-library to use (and > there's also the question whether to use OpenSSL via FFI or a native TLS > reimpl). So the platform-included `HTTP` package is not even able to > access `https://` URLs which is quite sad, as this also holds back > `cabal-install`'s ability to access `https://`-only repositories.

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Re: Cabal and simultaneous installations of the same package
by Michael Snoyman 25 Mar '15

25 Mar '15

I replied on the GSoC proposal itself, but since it was cross-posted to the mailing list, I'll include my comments here too: I've reviewed this proposal, and I think it outlines a step in a good direction. As I've discussed with Duncan in the past, my biggest concern around a system like this is the complexity of the UI for a developer; having to juggle different environments just to get basic work done could be a significant hurdle. As long as attention is paid to ensuring no "UI regression" for simple cases, I think this is worth pursuing. On Tue, Mar 24, 2015 at 7:17 PM Vishal Agrawal 1<vishal4556(a)gmail.com> wrote: > I am already planning to do a GSoC project based on it with a slightly > larger aim. You can find my work in progress proposal at > https://gist.github.com/fugyk/37510958b52589737274. Also I have written a > patch to make cabal non-destructive at > https://github.com/fugyk/cabal/commit/45ec5edbaada1fd063c67d6109e69efa0e732…. > Can you review the proposal and give me suggestions. >

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Fixing Fix
by David Feuer 24 Mar '15

24 Mar '15

There are a good number of different packages that define either newtype Fix f = Fix (f (Fix f)) or something equivalent except for naming. Most of the name variation is in the name of the data constructor and/or record selector. This does not look like an ideal situation to me. Most problematically, the only way to convert one to another is with unsafeCoerce. I think it would be rather nice to choose one canonical place for this definition, and let everyone else use it. Ideally, it would be nice to use some GHC pattern magic and such to paper over the differences between the data constructor names, but I don't know if that's possible or not. David Feuer

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