- Haskell-Cafe - Haskell.org

Cabal: wrapping namespace of a package into top-level module
by max ulidtko 24 May '11

24 May '11

Hi haskell-cafe. I have a package which builds with cabal pretty fine, but there is namespace issue which disturbs me. The problem is that the package exports (to the toplevel namespace!) some modules with fairly general names, like Tests, Basics, Applications. This is probably an oversight of the original package author, and the namespace shouldn't be organised like this... but it is. And I'm looking for a way to avoid potential namespace troubles should I install the package, other than going and reforming the namespace tree myself. What I was thinking about was some cabal option to "wrap" package's namespace into a toplevel module, say "PackageName", so that module Tests could be imported by usual code with `import PackageName.Tests`. Is that possible with cabal? Things are further complicated by the numerous intra-library imports. While the "outside" code refers to a module with PackageName.ModuleName, it would be very desirable that "inside" code used just straight ModuleName. ------ Regards, max ulidtko

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Re: [Haskell-cafe] ANNOUNCE: HaNS-2.1.0.0
by Don Stewart 24 May '11

24 May '11

Yay! The Hackage URL is: http://hackage.haskell.org/package/hans Cheers, Don On Tue, May 24, 2011 at 11:39 AM, Trevor Elliott <trevor(a)galois.com> wrote: > Galois, Inc. is pleased to announce the release of HaNS, the Haskell > Network Stack. HaNS is a lightweight, pure Haskell network stack that > can be used for Haskell networking in the context of the HaLVM, or with > a Linux tap device. Currently, HaNS supports 802.3, IPv4, ARP, DHCP > (partially), ICMP, UDP, and TCP. > > On Hackage: http://hackage.haskell.org/package/HaNS > Git repo: http://code.galois.com/cgi-bin/gitweb > > The TCP component is a port of Peng Li and Stephan Zdancewic's Haskell > TCP library, which in turn was translated from Norrish et al's HOL4 TCP > specification. > > What might you use HaNS for? Developing new and interesting networking > protocols, at any layer of the network stack, or your own variants of > existing protocols. HaNS allows HaLVM nodes to support networking, > meaning you can run experimental network services directly on top of the > HaLVM (without any pesky OS getting in the way). There are probably lots > of other cool applications of HaNS we haven't though of yet. > > HaNS is released under a BSD license, and should be considered > experimental at this stage. > > If you have any questions please contact the HaLVM team at > > halvm-devel(a)community.galois.com. > > -- Trevor Elliott (for the HaLVM team) > > P.S. If you're building with the HaLVM, make sure to add -fhalvm to your > cabal install invocation. > > > = References = > > HaLVM: http://halvm.org > Haskell TCP: http://hackage.haskell.org/package/tcp > > > _______________________________________________ > Libraries mailing list > Libraries(a)haskell.org > http://www.haskell.org/mailman/listinfo/libraries > >

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ANNOUNCE: HaNS-2.1.0.0
by Trevor Elliott 24 May '11

24 May '11

Galois, Inc. is pleased to announce the release of HaNS, the Haskell Network Stack. HaNS is a lightweight, pure Haskell network stack that can be used for Haskell networking in the context of the HaLVM, or with a Linux tap device. Currently, HaNS supports 802.3, IPv4, ARP, DHCP (partially), ICMP, UDP, and TCP. On Hackage: http://hackage.haskell.org/package/HaNS Git repo: http://code.galois.com/cgi-bin/gitweb The TCP component is a port of Peng Li and Stephan Zdancewic's Haskell TCP library, which in turn was translated from Norrish et al's HOL4 TCP specification. What might you use HaNS for? Developing new and interesting networking protocols, at any layer of the network stack, or your own variants of existing protocols. HaNS allows HaLVM nodes to support networking, meaning you can run experimental network services directly on top of the HaLVM (without any pesky OS getting in the way). There are probably lots of other cool applications of HaNS we haven't though of yet. HaNS is released under a BSD license, and should be considered experimental at this stage. If you have any questions please contact the HaLVM team at halvm-devel(a)community.galois.com. -- Trevor Elliott (for the HaLVM team) P.S. If you're building with the HaLVM, make sure to add -fhalvm to your cabal install invocation. = References = HaLVM: http://halvm.org Haskell TCP: http://hackage.haskell.org/package/tcp

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Hackage internal server error
by Niklas Broberg 24 May '11

24 May '11

nibro@nibro-laptop:~/src/haskell-src-exts$ cabal sdist Building source dist for haskell-src-exts-1.11.1... Preprocessing library haskell-src-exts-1.11.1... Source tarball created: dist/haskell-src-exts-1.11.1.tar.gz nibro@nibro-laptop:~/src/haskell-src-exts$ cabal upload dist/haskell-src-exts-1.11.1.tar.gz Hackage username: NiklasBroberg Hackage password: Uploading dist/haskell-src-exts-1.11.1.tar.gz... Error: dist/haskell-src-exts-1.11.1.tar.gz: 500 Internal Server Error 500 Internal Server Error <stdin>: hWaitForInput: invalid argument (Invalid or incomplete multibyte or wide character) nibro@nibro-laptop:~/src/haskell-src-exts$ Hackage's fault, cabal's fault, or (*gasp*) mine? Cheers, /Niklas

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Cabal: disabling -fvia-C
by Jacek Generowicz 24 May '11

24 May '11

I hope you will pardon another *ignorant* question. 'cabal install lambdabot' fails on Ubuntu Natty. According to the following exchange and bug report http://comments.gmane.org/gmane.comp.lang.haskell.cafe/88735 http://hackage.haskell.org/trac/ghc/ticket/5050 the workaround is not to use -fvia-C. I have found an {-# OPTION -fvia-C #-} deep inside the lambdabot code in Plugin/Pl/Common.hs. How can I tell cabal install to ignore this? Is there some command line option for doing so, or do I have to edit the source code and somehow persuade cabal to use my hacked version ?

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GHC 7, Platform 2011.2 vs OS X 10.5, Ubuntu 11.04
by Jacek Generowicz 24 May '11

24 May '11

[TL;DR: there's a concrete question at the bottom.] Once again I find myself in the pleasant situation where the slings and arrows of life in general are slightly less intense, and I manage to find a few spare minutes and some free brain cycles to dedicate to Haskell. Why not try GHC 7.0.3? (after all, GHC 7 has been out for a good few months, so the teething troubles should have passed by now), and there's a lovely new Haskell Platform 2011.2.0.1 to go with it, so, maybe this time, I'll actually be able to use some of the libraries that I tried and failed to install during my last period of Haskell study. The two computers I have available for playing with Haskell run OS X Leopard (10.5), and Ubuntu Natty (11.04). First up OS X: It seems that GHC 7 (and consequently Platform 2011.2) require OS X 10.6. OK, let's forget that one. Next up: Ubuntu. There's a Linux Link on the Haskell Platform Page. Ooooh, there's an Ubuntu link. Ooooh! there's even a package for Natty, great! Version 2010.1.0.0.1 WTF? Where's the 2011.2 package? There isn't one. OOoooKaaaayyyy. Any workarounds. Well, we can install from source, apparently. But we need GHC 7.0.3 first. Fine. Done. Now let's install the platorm. [Does obvious thing, compilation fails.] Hmm, let's follow the "Complete instructions for installing from source" http://www.vex.net/~trebla/haskell/haskell-platform.xhtml just in case I did something stupid. [Follows instructions: failure.] OK, maybe something somewhere is causing some confusion with previously installed versions of GHC, Cabal, whatever. [Performs Haskell pogrom on system: removes all traces of anything Haskell related. Follows "Complete instructions [...]" WORD ... FOR ... WORD. Failure]. Aaaaaaaaaaaaaaaaaaaargh ! I can't take it any more. I just want to write some Haskell, and every time I want to venture beyond the safe confines of the Prelude I get bogged down in installation hell. Next time I have some spare time, I will be more reluctant to risk having that time stolen by the Haskell infrastructure installation process. So, after this tale of agony, here are two concrete questions: a) Am I right in concluding that GHC 7.0.3 will not run on OS X 10.5 (without unreasonable effort)? b) On Ubuntu Natty I installed the generic linux GHC 7.0.3 binary. Downloaded Haskell Platform 2011.2.0.1 source distribution. ./ configure worked happily. make fails as follows. Building transformers-0.2.2.0 "/usr/local/haskell-platform-2011.2.0.1/bin/ghc" "--make" "Setup" "-o" "Setup" "-package" "Cabal-1.10.1.0" <command line>: cannot satisfy -package Cabal-1.10.1.0: Cabal-1.10.1.0-1fb2094e19492373b1a39284193e7984 is unusable due to missing or recursive dependencies: process-1.0.1.5-55dfaccf3a91c4cb8f6284a0bafef198 Could anybody help me get past this problem?

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SIGSEGV in yieldCapability ()
by Johannes Waldmann 24 May '11

24 May '11

Hi. What would be the reason for Program received signal SIGSEGV, Segmentation fault. 0x00000000006071de in yieldCapability () (gdb) where #0 0x00000000006071de in yieldCapability () #1 0x000000000060bc6b in schedule () #2 0x0000000000609294 in real_main () #3 0x000000000060938d in hs_main () #4 0x00007ffff6b07eff in __libc_start_main () from /lib/x86_64-linux-gnu/libc.so.6 #5 0x000000000040a589 in _start () this happens in a program compiled with ghc-7.0.3 (and also, with ghc-6.12.3), running with +RTS -N on i7-920, ubuntu 11 (kernel 2.6.38-8) Could this simply mean "heap exhausted"? Thanks - J.W.

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Bytestring package: Int and Int64
by Daniel Díaz 24 May '11

24 May '11

Hi, cafe, I just feel curiosity. In the bytestring package, Data.ByteString module, functions like length, index, and others with Int in its type signature, have Int64 in the analogous Data.ByteString.Lazy version. What is the reason? -- Daniel Díaz

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Cabal: top level dependency base -any
by Jacek Generowicz 24 May '11

24 May '11

Hi, Could anyone shed light on the meaning of this error message? cabal: cannot configure xmonad-0.9.1 It requires base ==3.* For the dependency on base ==3.* there are these packages: base-3.0.3.1 and base-3.0.3.2. However none of them are available. base-3.0.3.1 was excluded because of the top level dependency base -any base-3.0.3.2 was excluded because of the top level dependency base -any My guess is that "-any" would mean either that any version is acceptable (in which case should always work, including this time) or that "-any" means that any version is unacceptable, in which case it would never work, which is daft. So clearly I don't understand what it is trying to say. Any hints? Is this documented anywhere? Thanks.

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Imports in complex Setup.hs -- should we encourage/require PackageImports?
by John Millikin 24 May '11

24 May '11

Several libraries (notably Pandoc and Gtk2hs) have very complex Setup.hs scripts, which import several external libraries. In my experience, these imports are very fragile, because Cabal does not enforce package visibility in Setup.hs. For example, a Setup.hs that imports Control.Monad.Trans will break if "monads-tf" is installed, and one that imports System.FilePath will break if "system-filepath" is installed. My typical solution when this happens is to manually tweak the GHC package database before installing, but this is annoying and does not help other users. Based on a ticket in Cabal's Trac < http://hackage.haskell.org/trac/hackage/ticket/326 >, custom Setup.hs scripts are discouraged by the Cabal developers. I assume this means there will not be much development effort put towards an integrated solution (such as using -hide-all-packages and build-depends: when compiling Setup.hs). A possible solution is to ask developers with complex Setup.hs requirements to use the PackageImports language extension when importing external libraries. However, this places a burden on such developers, and I don't know if it's portable to non-GHC compilers. It would also need an analysis of currently published Hackage packages to see which have such scripts. Any ideas/comments? Has anyone by chance found a good solution to this?

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