- Haskell-Cafe - Haskell.org

unregisterised plan9 port
by * 21 Mar '11

21 Mar '11

Hi there. I am trying to get an unregisterised build of ghc 7.0.2 working and am having problems turning mangling off. When I build the compiler with GhcUnregisterized = YES GhcWithNativeCodeGen = NO SplitObjs = NO BeConservative = YES The 'evil mangler' is still used. When I disable it at the command line with -fno-asm-mangling the FB_ macro is still put into the generated C. I just want to turn everything related to this dreaded "evil mangler" off, and still produce working executables. Are there things that I could set in the build.mk file to do this, or is it more involved? I have read some things in the mailing list and the bug tracker that (to my ignorant and slightly confused ears) seem to suggest that this unregisterised is problematic or depreciated or something. If this is the case I would be perfectly happy using an older version of the compiler, and would be grateful if someone could point me to a specific older version number where this stuff builds with less hassel. I don't care how out of date it is. In case you are wondering, I am attempting to get an unregisterised port of ghc working in plan9, an operating system that has yet to be blessed with a haskell implementation (hugs doesn't count :P) Plan 9 has a gcc port, an older one, but it should be fine.

2 1

Re: [Haskell-cafe] Mime / Mail library
by John Lato 21 Mar '11

21 Mar '11

> From: Christopher Done <chrisdone(a)googlemail.com> > > On 20 March 2011 15:05, Pieter Laeremans <pieter(a)laeremans.org> wrote: > > > Hi all, > > > > The MIME package that can be found on hackage, uses String as input. > > Would i be considered better if there would be a version based on Text, > or > > ByteString ? > > > > I think the solution to this problem is a generic `string' package which > just provides a few classes. The MIME library would export an interface > that > only deals with instances of these classes, and whether you're using Text, > String, ByteString/Lazy/Char8, ropes, whatever, it's not the library > writer's concern or assumptions to make. > > We already have: > > http://hackage.haskell.org/packages/archive/string-combinators/0.6/doc/html… > < > http://hackage.haskell.org/packages/archive/string-combinators/0.6/doc/html… > > > Which works on Monoid and IsString, but there needs to be a class like "can > be read/outputted via IO" and one for read/show/serialize, both of which > are > important for speed. > > Anyone already done work on this? The Data.ByteString modules could export > some instances. It's fair enough that people who need fine-grained speed > use > the concrete types and all their special-purposes functions, but in the > general having to choose arbitrarily (often defaulting to String) is a > burden. Can't we standardize on a default set of String classes to use? > > I suppose I could try reducing Data.ByteString's function set into a set of > essential core methods, seeing as the ByteString modules are a very good > spec of what's required for a String type to be completely usable. > Data.ListLike (http://hackage.haskell.org/package/ListLike) provides this via the "StringLike" class (and StringLikeIO). There are built-in instances for Strings and ByteStrings, with orphan Text instances in http://hackage.haskell.org/package/listlike-instances. Probably the StringLike class could be extended to provide more (high-performance) methods, but I don't have a good idea of what's necessary. Suggestions are welcome! John L.

1 0

ANN: unix-bytestring: Unix/Posix-specific functions for ByteStrings.
by wren ng thornton 20 Mar '11

20 Mar '11

-------------------------------------------- -- unix-bytestring 0.3.2 -------------------------------------------- The unix-bytestring package offers a full selection of Unix/Posix-specific functions for reading and writing ByteStrings to Fds. -------------------------------------------- -- The Story Behind It All -------------------------------------------- A while back I needed a ByteString-based version of the System.Posix.IO String-based API. I coded up the new versions and submitted a patch to the unix package for adding them in[1]. But apparently, noone's much pleased with the System.Posix.IO API! In the ensuing discussion folks brought up their specific complaints and offered suggestions. So now, the couple of functions have become enough to release as its own package--- with the hope that one day it'll be rolled into the unix package. That's where you come in. The current API is more than good enough for anything I've needed, so I need your feedback on what you want from a ByteString-based Unix/Posix I/O library. I've looked through Roel van Dijk's reverse dependency analysis[2] to find the folks currently using the unix package. The maintainers of the following packages may be particularly interested in unix-bytestring: * HFuse * iteratee * iteratee-mtl * liboleg HFuse has complained about the lack of bindings for pread(2) and pwrite(2), which are included in unix-bytestring. The only standing complaint I haven't addressed is one expressed in the iteratee, iteratee-mtl, and liboleg packages which would prefer a return type of (Either Errno _) instead of throwing exceptions. [1] http://article.gmane.org/gmane.comp.lang.haskell.libraries/15390 [2] http://bifunctor.homelinux.net/~roel/cgi-bin/hackage-scripts/package/unix -------------------------------------------- -- Links -------------------------------------------- Homepage: http://code.haskell.org/~wren/ Hackage: http://hackage.haskell.org/package/unix-bytestring Darcs: http://community.haskell.org/~wren/unix-bytestring Haddock (Darcs version): http://community.haskell.org/~wren/unix-bytestring/dist/doc/html/unix-bytes… -- Live well, ~wren

1 0

Re: [Haskell-cafe] How to use roots package?
by Artyom Kazak 20 Mar '11

20 Mar '11

Oh. I have taken a wrong approach to the problem. I have written Newton method with cutting precision if it's more than N digits, and it finds an answer practically in no time. But still, it's very good, thank you!

1 0

Downloading Haskell repos from GitHub
by Gwern Branwen 20 Mar '11

20 Mar '11

Along the lines of http://blog.patch-tag.com/2010/03/13/mirroring-patch-tag/ for downloading all patch-tag.com repositories, I've begun to wonder how to download all Github repositories since more and more people seem to be using it. Nothing in http://develop.github.com/ seems especially useful for grabbing the git:// URLs of all repos by language - just by user. The only real list of repos by language seems to be gotten at via http://github.com/languages/Haskell/updated or http://github.com/languages/Haskell/created . (You might think http://github.com/languages/Haskell would be good, but no, it's just a few random repos by interest and not a full listing.) I looked at the HTML, and it looks possible to use tagsoup to get all 98 pages and then parse the entries to get the HTTP URLs of the repos, and then turn *that* into git:// URLs suitable for shelling out to 'git clone', but I can't help but wonder if maybe there's a better approach someone more familiar with Github would know. -- gwern

2 4

Gtk2hs multiple column TreeView with ListStore issue
by Кирилл Березин 20 Mar '11

20 Mar '11

I cannot force GTK to render data in TreeView with ListStore model with multiple columns through Haskell. I have the following code addTextColumn view name = do col <- treeViewColumnNew rend <- cellRendererTextNew treeViewColumnSetTitle col name treeViewColumnPackStart col rend True treeViewColumnSetExpand col True treeViewAppendColumn view col prepareTreeView view = do addTextColumn view "column1" addTextColumn view "column2" --adding data here Then I try to add some data, and there are problems. I tried these: --variant 1 (data TRow = TRow {one::String, two::String} model <- listStoreNew ([] :: [TRow]) listStoreAppend model $ TRow { one = "Foo", two = "Boo" } treeViewSetModel view model --variant 2 model <- listStoreNew ([] :: [[String]]) listStoreAppend model ["foo","boo"] treeViewSetModel view model --variant 3 model <- listStoreNew ([] :: [(String, String)]) listStoreAppend model ("foo", "boo") treeViewSetModel view model But in all cases I see the table with column header and one blank row inserted. Any help will be appreciated.

2 2

Defining subtraction for naturals
by wren ng thornton 19 Mar '11

19 Mar '11

Another question on particulars. When dealing with natural numbers, we run into the problem of defining subtraction. There are a few reasonable definitions: (1) If the result would drop below zero then throw an overflow error; (2) Use saturating subtraction, i.e. if the result would drop below zero then return zero; (3) Use type hackery to disallow performing subtraction when the result would drop below zero, e.g. by requiring a proof that the left argument is not less than the right. Dependently typed languages tend to use the second definition because it gives a pure total function (unlike the first) and because it's less obnoxious to use than the third. In Haskell the third would be even more obnoxious. So my question is, mathematically speaking, is there any reason to prefer the second option over the first or third? Purity aside, I mean; do the natural numbers with saturating subtraction form any interesting mathematical object, or is it just what we're stuck with? In a similar vein. Given a finite set (e.g., the natural numbers with some finite upper bound) and assuming we've already decided not to use modular arithmetic, is there any mathematical reason to prefer saturating addition and/or multiplication instead of throwing an overflow error? -- Live well, ~wren

8 10

Re: [Haskell-cafe] Trac login problem
by Jason Dagit 19 Mar '11

19 Mar '11

I've experienced very similar problems several times on both the ghc and cabal trac instances. I think resetting your password is (or was) breaking accounts. Now I just stick to guest login accounts on all the haskell.org trac instances. Ideally, all the trac instances, haskell wiki and etc, used a common identity system such as openid so we wouldn't need so many accounts. On Mar 19, 2011 11:28 AM, "Mihai Maruseac" <mihai.maruseac(a)gmail.com> wrote: Hi, I have a problem while trying to login to Haskell Trac instance. Entering the username and password that I know are valid gives me a login error. Trying to recover the password with the mail address that I use gives another error saying that there is no combination between the username and the mail. And, when trying to recreate the account if correctly complains that there is a valid username already. Can someone, please, look into it? Thanks, -- Mihai _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe(a)haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

1 0

Trac login problem
by Mihai Maruseac 19 Mar '11

19 Mar '11

Hi, I have a problem while trying to login to Haskell Trac instance. Entering the username and password that I know are valid gives me a login error. Trying to recover the password with the mail address that I use gives another error saying that there is no combination between the username and the mail. And, when trying to recreate the account if correctly complains that there is a valid username already. Can someone, please, look into it? Thanks, -- Mihai

1 0

[haskell-gsoc] Haskell.org Google Summer of Code 2011
by Edward Kmett 19 Mar '11

19 Mar '11

It is that time of year again. The Google Summer of Code is upon us! *Sign Up Information* If you are a student and want to sign up to make $5,000 for hacking on the code you love over the summer or are willing to help out as a mentor, now is the time to act. Please sign up by adding your name to the list at: http://hackage.haskell.org/trac/summer-of-code/wiki/People2011 Our main wiki entry for the Summer of Code 2010 is now online: http://hackage.haskell.org/trac/summer-of-code/wiki/Soc2011 If you are interested in applying as a student, here are some guidelines: http://hackage.haskell.org/trac/summer-of-code/wiki/StudApply2011 The official deadline for student applications with Google is April 8th, but if you are interested please add your name to the People2010 page above, as soon as possible. *Interested in helping out, but not sure how? * There are a number of ideas that we've been collecting for projects available through the trac http://hackage.haskell.org/trac/summer-of-code/report/1 and which have been collecting over time in a reddit: http://www.reddit.com/r/haskell_proposals/top/ <http://www.reddit.com/r/haskell_proposals/top/>Unfortunately, reddit doesn't let you comment on topics after they become archived, and most of the topics in the haskell_proposals reddit have been. While the reddit is a great place to discuss proposals, we had to choose one mechanism to supply Google with our ideas officially, so please submit proposals <http://hackage.haskell.org/trac/summer-of-code/newticket> to the trac once you have hashed out something you like to work on, or which would be an appropriately beneficial project for a summer worth of work. *Helping Out Darcs * Haskell.org <http://haskell.org/> is going to continue to act as an umbrella organization covering darcs <http://darcs.net/> for the Summer of Code once more. If you are interested in helping them out, they also have a page full of project ideas as well: http://wiki.darcs.net/GoogleSummerOfCode Again, please submit proposals<http://hackage.haskell.org/trac/summer-of-code/newticket> as tickets to the trac if you can think of something you'd like to work on. *More Information* Here are a bunch of relevant links that may be able to answer your questions: Google's Summer of Code Homepage <http://socghop.appspot.com/> Google's Summer of Code 2011 FAQ<http://socghop.appspot.com/document/show/gsoc_program/google/gsoc2011/faqs> Google's Summer of Code 2011 Timeline<http://socghop.appspot.com/document/show/gsoc_program/google/gsoc2011/timel…> Google's Summer of Code Wiki Knowledge Base<http://code.google.com/p/google-summer-of-code/wiki/WikiStart> Of course, you can always feel free to email me <ekmett(a)gmail.com> or inquire on irc.freenode.net #haskell-soc or with the darcs folks over on #darcs for more information. If you don't have an IRC client, you can get there from: http://webchat.freenode.net Thank you all very much and we look forward to another successful Summer of Code! -Edward Kmett

1 0