- Haskell-Cafe - Haskell.org

high probability of installation problems and quality of the glorious implementation
by FFT 06 Apr '09

06 Apr '09

I'm still learning Haskell and also evaluating whether I want to use the language in my work. It seems like a fascinating language so far (although I don't know if laziness will be a detriment later for me eventually), but I'm a bit worried about the overall quality of its GHC implementation. For example, I tried installing GHC-6.10.2 on my Ubuntu 8.04 machine (probably the most mainstream Linux these days). 1st attempt: binary => failed "the impossible happened, report bug" (I think it's already in bugzilla for an even earlier version) 2nd attempt: source and docs => followed README, but "make" failed while building docs 3rd attempt: source only, no docs => make install succeeded, but ghci now seems to have its "readline" screwed up (no editing, can't quit even with Ctrl-C or Ctrl-D), while Ubuntu-bundled 6.8.* ghci works fine in this regard. If these kinds of issues are common only during installation, I can live with that, but if GHC is flaky overall, having to deal with this may cancel out whatever productivity advantages Haskell provides. If the quality of the installation procedures is different from the compiler itself, can you explain why?

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minor typo in "The Haskell 98 Report"
by Benjamin L.Russell 06 Apr '09

06 Apr '09

Today, as I was reading through "The Haskell 98 Report" (see http://www.haskell.org/onlinereport/) I came across a minor typo, but it seems that the only way to fix such typos is to report them on one of the Haskell mailing lists; viz.: >The original committees ceased to exist when the original Haskell 98 Reports were published, so every change was instead proposed to the entire Haskell mailing list. Therefore, please allow me to report this typo, though minor, here, as follows: The Haskell 98 Report - Preface (see http://www.haskell.org/onlinereport/preface-jfp.html) under the heading "Haskell 98: language and libraries," fourth paragraph, second line: >If these program were to be portable, a set of libraries would have to be standardised too. should be as follows: >If these programs were to be portable, a set of libraries would have to be standardised too. (I.e., the word "program" should be plural.) Is this the proper place to report any forthcoming similar typos? -- Benjamin L. Russell -- Benjamin L. Russell / DekuDekuplex at Yahoo dot com http://dekudekuplex.wordpress.com/ Translator/Interpreter / Mobile: +011 81 80-3603-6725 "Furuike ya, kawazu tobikomu mizu no oto." -- Matsuo Basho^

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Re: [Haskell] [OT] Plural forms of the word "octopus" [Was: Re: Marketing Haskell]
by ajb＠spamcop.net 06 Apr '09

06 Apr '09

[Shifted to haskell-cafe.] G'day all. Quoting "Benjamin L.Russell" <DekuDekuplex(a)Yahoo.com>: > According to the Merriam-Webster Online Dictionary, it is "topoi" (see > http://www.merriam-webster.com/dictionary/topos) Topoi form a certain class of category. You can study topous, you can prove theorems about topois and you can discover properties of topon. (That last one is an omega, so it's pronounced more like "top-own".) > Where did you find "octoposi?" In my ancient copy of Liddell and Scott. Here's the online entry: http://tinyurl.com/ck8gst Cheers, Andrew Bromage

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Linking hmatrix without LAPACK
by Duane Johnson 06 Apr '09

06 Apr '09

I'm curious if there is a quick fix to this. I installed GLS and hmatrix, and it runs wonderfully together in ghci. When I run ghc -- make, however, I run into the following link dependency: Linking SilkwormGame ... Undefined symbols: "_dgemm_", referenced from: _multiplyR in libHShmatrix-0.5.0.1.a(lapack-aux.o) "_dgesv_", referenced from: _linearSolveR_l in libHShmatrix-0.5.0.1.a(lapack-aux.o) ... etc Is there a way to tell ghc to not link these? Or am I making a poor assumption that if my code runs in ghci, it does not need LAPACK? Thanks, Duane Johnson

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cabal build on mac os 10.5.6 , can't find gmp
by brian 06 Apr '09

06 Apr '09

Hi, Cabal won't build zlib because it can't find libgmp. It's there, in /sw/lib (fink installation). I've modified the bootstrap script and added -L/sw/lib to the ghc options. This is a mystery in itself because ghc is itself a fink package and should know where gmp is, so that's already a bad sign. I can get to the build step with the additional -L option but then ./ Setup fails again because it can't find gmp. Help .... ? Thanks, Brian

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haskelldb, how to escape table names
by Günther Schmidt 06 Apr '09

06 Apr '09

Hi, how can I "escape" table and column names, from something like: kh-internes-kennz to this: [kh-internes-kennz] ? Günther

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Combining sequences
by michael rice 06 Apr '09

06 Apr '09

Is there a simple way to combine two sequences that are in ascending order into a single sequence that's also in ascending order? An example would be the squares [1,4,9,16,25..] combined with the cubes [1,8,27,64,125..] to form [1,1,4,8,9,16,25,27..]. Michael

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Reverting to any old version using Darcs
by Peter Verswyvelen 06 Apr '09

06 Apr '09

Rumor goes that this is very difficult to do with Darcs. Is this correct?

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Confused about readline/editline
by Martijn van Steenbergen 05 Apr '09

05 Apr '09

Hello café, I'm trying to write an executable that depends on Yogurt-0.3, readline (indirectly) and hint. However, including hint in the build-depends field causes cabal to link the executable against editline instead of readline. Here is a small test case: File: Test.cabal > Name: Test > Version: 0 > > Build-Type: Simple > Cabal-Version: >= 1.2 > > Executable test > Main-Is: Test.hs > Build-Depends: base, Yogurt, hint > GHC-Options: -threaded File: Test.hs > module Main where > > import Network.Yogurt > > main:: IO () > main = do > connect "eclipse.cs.pdx.edu" 7680 (return ()) The example doesn't use any functions from hint, but simply mentioning it in the cabal file causes this behaviour. What's going on? How can I fix or work around this? I am able to reproduce this behaviour in two configurations: * Leopard Intel; cabal-install version 0.6.2, using version 1.6.0.1 of the Cabal library; GHC 6.10.1 * Ubuntu; cabal-install version 0.6.2, using version 1.6.0.3 of the Cabal library; GHC 6.10.2 Thank you very much in advance, Martijn.

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Hackage not updating package list
by Johan Tibell 05 Apr '09

05 Apr '09

Hi, I just uploaded network-2.2.1. It appears on Hackage [1] but a `cabal update` followed by `cabal install network-2.2.1` results in: Resolving dependencies... cabal: There is no available version of network that satisfies ==2.2.1 The upload took a very long time and it seemed to time out at some point. My guess is that Hackage got itself into an inconsistent state. Could someone who has access to the Hackage server check what happened? 1. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/network-2.2.1 Cheers, Johan

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