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Today's Topics:
1. svgcairo/ghc vis cabal install error.. (madhub)
2. Re: Fwd: GHC 7.10 Prelude: we need your opinion (Darren Grant)
----------------------------------------------------------------------
Message: 1
Date: Tue, 10 Feb 2015 22:57:53 -0500
From: madhub <[email protected]>
To: [email protected], [email protected]
Subject: [Haskell-beginners] svgcairo/ghc vis cabal install error..
Message-ID: <[email protected]>
Content-Type: text/plain; charset="utf-8"
Hi !,
I tried installing svgcairo ( for installing ghc vis ). I am getting following
error. Could you please help me out install ghc vis.
Thanks in advance
Madhu
? environment details.
I am on mac yosomite with gcc provided by OS X. Following is the gcc ?version
22:54:34:~$ gcc --version
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr
--with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 6.0 (clang-600.0.56) (based on LLVM 3.5svn)
Target: x86_64-apple-darwin14.1.0
Thread model: posix
export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig:/opt/X11/lib/pkgconfig
export LDFLAGS=-L/usr/local/lib
export CFLAGS=-I/usr/local/include
export LIBS=-L/usr/local/lib
svgcairo error
===============
Configuring svgcairo-0.13.0.1...
Building svgcairo-0.13.0.1...
Preprocessing library svgcairo-0.13.0.1...
gtk2hsC2hs: Error in C header file.
/usr/include/sys/qos.h:124: (column 34) [FATAL]
>>> Syntax error!
The symbol `__attribute__' does not fit here.
cabal: Error: some packages failed to install:
svgcairo-0.13.0.1 failed during the building phase. The exception was:
ExitFailure 1
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Message: 2
Date: Tue, 10 Feb 2015 21:25:30 -0800
From: Darren Grant <[email protected]>
To: The Haskell-Beginners Mailing List - Discussion of primarily
beginner-level topics related to Haskell <[email protected]>
Subject: Re: [Haskell-beginners] Fwd: GHC 7.10 Prelude: we need your
opinion
Message-ID:
<ca+9vpfekugjlkgfnweyeblrsfrd6yuupys-1doz8b_ndmj+...@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"
Julian,
You're not alone. The lack of a general fold was a stumbling block for me
as well. I'd rather not propagate the special cases any further than
absolutely necessary when a solution is known. It's easier to point to
outdated material and explain how the situation was improved rather than
continue to propagate mistakes in literature.
Cheers,
Darren
On Tue, Feb 10, 2015 at 2:15 PM, Julian Birch <[email protected]>
wrote:
> Ironically, as a beginner, I supported FTP. As a beginner, I don't need to
> worry about legacy compatibility, but I do worry about cognitive overload.
> And actually, for someone coming from almost any other language, having a
> non-general fold is a speedbump for me.
>
> As for sequence in its full generality, I don't know if I completely grasp
> it, but the basic idea of swapping two typeclasses around I found the first
> time I hoogled for something that did exactly that.
>
> J
>
> On 10 February 2015 at 16:46, Kim-Ee Yeoh <[email protected]> wrote:
>
>> Simon PJ missed out the haskell-beginners list, but I encourage you to
>> fill out the survey below as well.
>>
>> Now you may ask, "Well, I'm still learning haskell and I don't know
>> enough."
>>
>> But consider that by being on this list and by haskelling whatever you
>> may consider as utterly insignificant, you're still waaaaaaaay ahead than
>> those who have yet to reach haskell at all.
>>
>> Your opinion counts.
>>
>> Because those _after_ you will help provide jobs by creating haskell
>> projects, just like you.
>>
>> But unlike them, you get to influence the haskell of tomorrow that will
>> be their first encounter, whether that would be a haskell that's friendlier
>> or more @#$%^& than what it is today.
>>
>> The survey link is here:
>> *http://goo.gl/forms/XP1W2JdfpX <http://goo.gl/forms/XP1W2JdfpX>*
>>
>> Summaries (each quite long) are here:
>>
>> ? Overall summary:
>> https://ghc.haskell.org/trac/ghc/wiki/Prelude710
>> <https://www.google.com/url?q=https%3A%2F%2Fghc.haskell.org%2Ftrac%2Fghc%2Fwiki%2FPrelude710&sa=D&sntz=1&usg=AFQjCNE1p5w-YCXC7ixebvwObayuV7Ut4w>
>>
>> ? Details of Plan List:
>> https://ghc.haskell.org/trac/ghc/wiki/Prelude710/List
>> <https://www.google.com/url?q=https%3A%2F%2Fghc.haskell.org%2Ftrac%2Fghc%2Fwiki%2FPrelude710%2FList&sa=D&sntz=1&usg=AFQjCNHaufeSwtIsvZwdVXwP9F9G45zLSA>
>> ? Details of Plan FTP:
>> https://ghc.haskell.org/trac/ghc/wiki/Prelude710/FTP
>> <https://www.google.com/url?q=https%3A%2F%2Fghc.haskell.org%2Ftrac%2Fghc%2Fwiki%2FPrelude710%2FFTP&sa=D&sntz=1&usg=AFQjCNHbhNyIwAbcOd3JfikIhD6S7rc-vw>
>>
>> Fwiw, I voted to delay FTP. In fact, here's what I wrote:
>>
>> "FTP is rushed and potentially unstable. I don't think we understand all
>> about Traversable that we think we do, which might mean another big Prelude
>> overhaul in the future.
>>
>> Actually, FTP doesn't even belong in 7.12 per se. It belongs in a new
>> Haskell language standard and if that coincides with GHC 7.12, great. If
>> not, it can wait for GHC 8.x and up."
>>
>> Because I've been keeping tabs on FTP I wrote my opinion without perusing
>> the summaries, but on doing so later, I stumbled upon the following points
>> that happen to reflect my exact observations, points that are relevant to
>> learning haskell and growing the haskell community:
>>
>> https://ghc.haskell.org/trac/ghc/wiki/Prelude710/List
>>
>>
>> - The existing corpus of books, tutorials, syllabi, and the like
>> usually have a significant portion of the text dedicated to these very
>> Prelude functions - and they would all need significant revision.
>>
>>
>> - Teaching beginners what sequence means in its full generality is
>> going to be a challenge.
>>
>>
>> - While teaching beginners who end up on #haskell IRC might be
>> possible, this is likely to increase the "bounce" rate, people who see
>> Haskell, play around, and run away scared. I think Haskell probably has a
>> higher bounce rate than most other languages, making it worse would be
>> bad.
>>
>>
>> Whether you agree or disagree with the above, now's the time to make
>> yourself heard. The survey closes Feb 21.
>>
>> p.s. Needless to say, feel free to discuss FTP on this list should your
>> opinion need a sounding board and a bit of time (not too long!) to firm up.
>>
>> -- Kim-Ee
>>
>> ---------- Forwarded message ----------
>> From: Simon Peyton Jones <[email protected]>
>> Date: Tue, Feb 10, 2015 at 10:50 PM
>> Subject: GHC 7.10 Prelude: we need your opinion
>> To: "[email protected]" <[email protected]>, "Haskell Cafe (
>> [email protected])" <[email protected]>, GHC users <
>> [email protected]>, "[email protected]" <
>> [email protected]>
>>
>>
>> Haskell Friends
>>
>> *This email asks for your help in deciding how to proceed with some
>> Prelude changes in GHC 7.10. Please read on, but all the info is also at
>> the survey link, here: http://goo.gl/forms/XP1W2JdfpX
>> <http://goo.gl/forms/XP1W2JdfpX>. Deadline is 21 Feb.*
>>
>>
>>
>> The ?Core Libraries Committee (CLC) is responsible for developing the
>> core libraries that ship with GHC. This is an important but painstaking
>> task, and we owe the CLC a big vote of thanks for taking it on.
>>
>> For over a year the CLC has been working on integrating the *Foldable
>> and Traversable classes* (shipped in base in GHC 7.8) into the core
>> libraries, and into the Prelude in particular. Detailed planning for GHC
>> 7.10 started in the autumn of 2014, and the CLC went ahead with this
>> integration.
>>
>> Then we had a failure of communication. As these changes affect the
>> Prelude, which is in scope for all users of Haskell, these changes should
>> be held to a higher bar than the regular libraries@ review process.
>> However, the Foldable/Traversable changes were not particularly well
>> signposted. Many people have only recently woken up to them, and some have
>> objected (both in principle and detail).
>>
>> This is an extremely unfortunate situation. On the one hand we are at RC2
>> for GHC 7.10, so library authors have invested effort in updating their
>> libraries to the new Prelude. On the other, altering the Prelude is in
>> effect altering the language, something we take pretty seriously. We should
>> have had this debate back in 2014, but here we are, and it is unproductive
>> to argue about whose fault it is. We all share responsibility.
>>
>> We need to decide what to do now. A small group of us met by Skype and
>> we've decided to do this:
>>
>> ? Push back GHC 7.10's release by at least a month, to late
>> March. This delay also gives us breathing space to address an unrelated
>> show-stopping bug, Trac #9858.
>>
>> ? Invite input from the Haskell community on which of two
>> approaches to adopt (this survey <http://goo.gl/forms/XP1W2JdfpX>). The
>> main questions revolve around impact on the Haskell ecosystem (commercial
>> applications, teaching, libraries, etc etc), so we want to ask your opinion
>> rather than guess it.
>>
>> ? Ask Simon Marlow and Simon Peyton Jones to decide which
>> approach to follow for GHC 7.10.
>>
>> Wiki pages have been created summarizing these two primary alternatives,
>> including many more points and counter-points and technical details:
>>
>> ? Overall summary:
>> https://ghc.haskell.org/trac/ghc/wiki/Prelude710
>> <https://www.google.com/url?q=https%3A%2F%2Fghc.haskell.org%2Ftrac%2Fghc%2Fwiki%2FPrelude710&sa=D&sntz=1&usg=AFQjCNE1p5w-YCXC7ixebvwObayuV7Ut4w>
>>
>> ? Details of Plan List:
>> https://ghc.haskell.org/trac/ghc/wiki/Prelude710/List
>> <https://www.google.com/url?q=https%3A%2F%2Fghc.haskell.org%2Ftrac%2Fghc%2Fwiki%2FPrelude710%2FList&sa=D&sntz=1&usg=AFQjCNHaufeSwtIsvZwdVXwP9F9G45zLSA>
>>
>> ? Details of Plan FTP:
>> https://ghc.haskell.org/trac/ghc/wiki/Prelude710/FTP
>> <https://www.google.com/url?q=https%3A%2F%2Fghc.haskell.org%2Ftrac%2Fghc%2Fwiki%2FPrelude710%2FFTP&sa=D&sntz=1&usg=AFQjCNHbhNyIwAbcOd3JfikIhD6S7rc-vw>
>>
>> This survey invites your input on which plan we should follow. Would you
>> please
>>
>> ? Read the details of the alternative plans on the three wiki
>> pages above
>>
>> ? Add your response to the survey
>> <http://goo.gl/forms/XP1W2JdfpX>
>>
>> Please do read the background. Well-informed responses will help. Thank
>> you!
>>
>> *DEADLINE: 21 February 2015*
>>
>> Simon PJ
>>
>> _______________________________________________
>> ghc-devs mailing list
>> [email protected]
>> http://www.haskell.org/mailman/listinfo/ghc-devs
>>
>>
>>
>> _______________________________________________
>> Beginners mailing list
>> [email protected]
>> http://www.haskell.org/mailman/listinfo/beginners
>>
>>
>
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