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Building ghc-7.6.3 under cygwin

haskell-cafe - Sat, 01/18/2014 - 1:11pm
Trying to build 7.6.3-x86_64-unknown-linux under cygwin. $ ./configure checking for path to top of build tree... ./configure: line 2121: utils/ghc-pwd/dist-install/build/tmp/ghc-pwd: cannot execute binary file configure: error: cannot determine current directory Not sure it is a libgmp issue, because linking doesn't help: $ ln -s /usr/lib/libgmp.dll.a /usr/lib/libgmp.so.3 Any ideas what is going on and how to fix this? _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe< at >haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
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Hashtables: 'Basic' hashtables performance quirks on Win64

libraries list - Sat, 01/18/2014 - 11:38am
Having built Agda on 64-bit GHC 7.6.3 on Windows I've stumbled on Agda being unbearable slow (I tried it on Penryn and Sandy Bridge computers). The culprit turned out to be Agda uses 'BasicHashTable' in src/full/Agda/TypeChecking/Serialise.hs (line 98). Switching either to Cuckoo or Linear immediately cures the problem. The problem does not manifest itself on 32-bit Windows build or any Linux build. Also 'Basic' hashtable perform better than Cuckoo and Linear in standard benchmarks on Win64. And at the same time in Agda scenario it's performance degrades by a *couple of orders of magnitude*! Thus, *all* things are important here: 64-bit, Windows, Agda use case. I wonder what stands behind this behaviour? What are specifics of 'Basic' hashtable implementation and how to fix this or should this be fixed at all? Regards, Kyra
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Conal Elliott's home page

del.icio.us/haskell - Sat, 01/18/2014 - 7:12am
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bitbucket.org

del.icio.us/haskell - Sat, 01/18/2014 - 6:47am
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bitbucket.org

del.icio.us/haskell - Sat, 01/18/2014 - 6:47am
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github.com

del.icio.us/haskell - Sat, 01/18/2014 - 6:28am
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github.com

del.icio.us/haskell - Sat, 01/18/2014 - 6:28am
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github.com

del.icio.us/haskell - Sat, 01/18/2014 - 6:28am
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github.com

del.icio.us/haskell - Sat, 01/18/2014 - 6:28am
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Philip Wadler: My friends wonder why any intelligent Scot would vote Yes

Planet Haskell - Sat, 01/18/2014 - 5:56am
David Donnison on Bella Caledonia presents a concise argument for independence that puts, far better than I could, my own views.
They asked me about many of the dilemmas we have been pondering in Scotland in the aftermath of our white paper – and most of them could not understand why any intelligent Scot would be voting for independence. It was an afternoon that compelled me to clarify my own thinking.
What matters most, I said, is not how an independent Scotland will fare. Independence will of course bring teething troubles of many kinds; but the Scots, if they choose to break away, will make their way in the world pretty successfully. What matters most, I said, is what you are doing in England; what kind of country you want to make of the UK; and whether we in Scotland want to be part of it.
...
The Scottish ‘political class’ assume that proposals for new policies should help to create a fairer and more equal society where there will be greater social justice. They assume that proposals for solving social problems should be prepared in active consultation with the kinds of people who experience these problems. Of course they do not always live up to these aspirations; but our political class assume that they will be generally accepted by Scottish governments, whoever wins our next elections. They are not contentious. None of that can be said of England.
I could give various examples of the impact of these divergent cultures, but one will have to do. When our first minister was taking questions at the press conference launching the independence white paper, a correspondent from the Daily Telegraph said (roughly speaking – I took no note): ‘Your plans for Scotland’s future are splendid. But in a country with high rates of unemployment and high proportions of pensioners, how can you pay for all this?’ To which Salmond replied: ‘That would indeed be difficult if nothing changes. But an independent Scotland will attract more young workers’. To which the Telegraph man – thinking he had a killer question – said: ‘You mean more immigrants?’. ‘Yes,’ said Salmond. ‘They make an important and creative contribution to our society and we need more of them.’ Could any serious English politician have said this? And if it had been said, would it have passed unnoticed, as it did in Scotland?
...
We shall all have to make our best guesses at England’s political trends when the referendum comes – eight months before the next Westminster election which may give us a few pointers. But if staying in the UK seems likely to mean living in a country that leaves the European Union (Miliband, if he wins the election, has not yet promised a referendum on that, but neither has he refused one); if it is to be a country that continues to impose increasingly punitive and humiliating sanctions on its poorest citizens who live on social security benefits (Labour spokespersons on this subject seem determined to show they will match the Tories’ brutalities); if the Human Rights Act is to be repealed (as our present home secretary promises); if the UK continues to have the most centralised government in the Western world (strangling local governments and killing off civic leadership); if ‘green’ policies are to have low priority; and if our armed forces are to remain mercenary outriders to American foreign policy; then I would rather get out, whatever the hazards of independence.
It’s a white paper, agreed by the main political parties, on the future plans and priorities, not of Scotland but of the rest of the UK, that I need. I guess I’ll have to place my bet without waiting for that.Spotted via @cstross and @andrewdrucker.
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www.etnassoft.com

del.icio.us/haskell - Sat, 01/18/2014 - 5:08am
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www.etnassoft.com

del.icio.us/haskell - Sat, 01/18/2014 - 5:08am
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language-puppet: The stm-firehose package

Planet Haskell - Sat, 01/18/2014 - 4:55am

I recently needed a specific kind of publish-subscribe primitive, where the publisher must not block, and that should not leak memory. It is published as the stm-firehose package.

It exposes an STM interface (built upon TBMQueue), but also higher level helpers. My use case is to be able to tap on a message stream at will, and observe some of the messages as they flow through the infrastructure. The clients will join and leave at any time, possibly from a low bandwidth connection. This means that they might not be able to cope with the traffic, but this should not adversely affect the publisher or other clients.

To cover common use cases, two helpers are exposed in the Data.Conduit.Network.Firehose module :

  • firehoseApp: creates a WAI application that lets firehose clients connect through a web interface.
  • firehoseConduit: spawns a WARP server waiting for clients to connect, and returns a Conduit that will make all messages traversing it available to clients.

Finally, a specialized version of firehoseConduit, called firehose, has been included in the Data.Conduit.Firehose module of the hslogstash package, in the name of fireHose. This version is specialized for querying logstash messages, and yes, the naming of the function and module could have been better.

It might have been a better idea to just create a TCP server for the helper functions, instead of a more complex HTTP server, but this would have required writing a custom protocol for handling the client “preferences” in the kind of messages they would like to see. As it stands, the user of the helper functions can pass a filtering function that can adjust its behavior based on the client HTTP request. This is exploited in the logstash-specific helper function by letting the client specify the list of message types he would like to see in the URL.

As a side note, there have been quite a few improvement and bug fixes in language-puppet since last time I blogged about it. There still are a few issues to close before releasing a new version.

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Open researcher position at Create-Net Italy

haskell-cafe - Sat, 01/18/2014 - 4:03am
Dear Haskell-cafe, CREATE-NET, a research center located in Trento, Italy, is hiring one researcher on distributed system management. The responsibility of the candidate will be to contribute to the research topic of Energy Efficiency in the Cloud with particular focus on making cloud-running applications energy-aware. The techniques used will include Constraint Programming and Functional Programming to some extent. We offer competitive compensation and a stimulating work environment in the research and innovation sector. The scenic landscape of Italian Alps doesn't hurt either. If you are interested, please submit your application to careers< at >create-net.org (with me in copy). Details on the open position and ideal profile may be found on http://www.create-net.org/it/node/3197 Don't hesitate to contact me for more details! Cheers, Corentin Dupont CREATE-NET www.create-net.org www.corentindupont.info _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe< at >haskell.org http://
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www.slideshare.net

del.icio.us/haskell - Sat, 01/18/2014 - 1:57am
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