- Haskell-Cafe - Haskell.org

why can't you surround (+) in backticks and have it be infix?
by tphyahoo 08 Jan '07

08 Jan '07

"Issues: In Haskell, any function or constructor can be enclosed in backticks and then used as an infix operator. " from http://www-users.cs.york.ac.uk/~mfn/hacle/issues/node2.html But this seems to be contradicted by... from #haskell -- 09:19 < tphyahoo> > let func = (+) in 1 `func` 2 -- 09:19 < lambdabot> 3 -- 09:20 < tphyahoo> but ...... -- 09:20 < tphyahoo> 1 `(+)` 2 -- 09:20 < tphyahoo> > 1 `(+)` 2 -- 09:20 < lambdabot> Parse error (+) is a function, is it not? Where's the rub? thomas. -- View this message in context: http://www.nabble.com/why-can%27t-you-surround-%28%2B%29-in-backticks-and-h… Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com.

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hsffig build problem
by Jeff Polakow 08 Jan '07

08 Jan '07

Hello, I am trying to install hsffig and I get the following error: bash$ make : : Linking cabal-setup.exe ... Distribution/Simple/Configure.o:fake:(.text+0x74fd): undefined reference to `SHGetFolderPath@20' collect2: ld returned 1 exit status make: *** [cabal-setup] Error 1 I am using ghc6.6 in cygwin on windows XP. Has anyone else encountered and/or overcome this? thanks, Jeff --- This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and destroy this e-mail. Any unauthorized copying, disclosure or distribution of the material in this e-mail is strictly forbidden.

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Re: [Haskell-cafe] no end to the build errors! (wxhaskell, afrp)
by Yang 08 Jan '07

08 Jan '07

thanks, now wxhaskell is installed. (i recommend adding this detail to the docs - i didn't see the message at the end of the make job at all because of the tools i use to automate this process.) now the error i get from wxfruit is: $ ghc --make WXFruit.hs [1 of 1] Compiling WXFruit ( WXFruit.hs, WXFruit.o ) WXFruit.hs:81:31: parse error on input `->' On 1/7/07, Brandon S. Allbery KF8NH allbery-at-ece.cmu.edu |haskell-cafe| <...> wrote: > > On Jan 7, 2007, at 20:54 , Yang wrote: > > > WXFruit.hs:12:17: > > Could not find module `Graphics.UI.WX': > > Hm. Did you install the whole thing? You need to do "make; make > install; make wx; make wx-install" to get all of it --- and > Graphics.UI.WX is in the latter group, IIRC. If you do only the > first part then you only get wxcore, which isn't so useful. > > -- > brandon s. allbery [linux,solaris,freebsd,perl] allbery(a)kf8nh.com > system administrator [openafs,heimdal,too many hats] allbery(a)ece.cmu.edu > electrical and computer engineering, carnegie mellon university KF8NH > > > >

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no end to the build errors! (wxhaskell, afrp)
by Yang 08 Jan '07

08 Jan '07

argh, still more build errors on various fronts. i'm using ghc-6.6 on fedora core 5 unless otherwise noted. thanks in advance for help on any of these. a lot of this is part of my attempt to learn more about and play with a high-level functional gui library (and, of course, for getting a better grasp on what frp and arrows are all about) after realizing that i would never ever be able to get fruit working. i have so far found wxfruit (built on wxhaskell) and FG (built on gtk). i am interested in implementing a similarly 'highly-declarative' ui library built on hscurses.widgets. == wxhaskell-0.9.4 == $ make ... wx/src/Graphics/UI/WX/Types.hs:94:0: Bad interface file: out/wx/imports/Graphics/UI/WXCore/Types.hi Something is amiss; requested module wx:Graphics.UI.WXCore.Types differs from name found in the interface file wxcore:Graphics.UI.WXCore.Types make: *** [out/wx/imports/Graphics/UI/WX/Types.o] Error 1 == afrp-0.4 == after removing all references to packages 'lang' and 'concurrent' and changing all "import IORef" to "import Data.IORef as IORef": ghc -c -fglasgow-exts -O -o AFRPUtilities.o AFRPUtilities.hs AFRPUtilities.hs:169:46: Ambiguous occurrence `>>^' It could refer to either `>>^', defined at AFRPUtilities.hs:106:2 or `>>^', imported from AFRP at AFRPUtilities.hs:90:0-10 AFRPUtilities.hs:178:27: Ambiguous occurrence `>>^' It could refer to either `>>^', defined at AFRPUtilities.hs:106:2 or `>>^', imported from AFRP at AFRPUtilities.hs:90:0-10 AFRPUtilities.hs:184:46: Ambiguous occurrence `>>^' It could refer to either `>>^', defined at AFRPUtilities.hs:106:2 or `>>^', imported from AFRP at AFRPUtilities.hs:90:0-10 AFRPUtilities.hs:246:32: Ambiguous occurrence `^>>' It could refer to either `^>>', defined at AFRPUtilities.hs:103:2 or `^>>', imported from AFRP at AFRPUtilities.hs:90:0-10 AFRPUtilities.hs:247:33: Ambiguous occurrence `^>>' It could refer to either `^>>', defined at AFRPUtilities.hs:103:2 or `^>>', imported from AFRP at AFRPUtilities.hs:90:0-10 AFRPUtilities.hs:304:62: Ambiguous occurrence `>>^' It could refer to either `>>^', defined at AFRPUtilities.hs:106:2 or `>>^', imported from AFRP at AFRPUtilities.hs:90:0-10 == FG == $ ghc --make FG.hs [1 of 1] Compiling FG ( FG.hs, FG.o ) FG.hs:115:31: Module `Graphics.UI.Gtk' does not export `button' FG.hs:115:39: Module `Graphics.UI.Gtk' does not export `visible' when removing those two `hiding` params: [1 of 1] Compiling FG ( FG.hs, FG.o ) FG.hs:562:69: Couldn't match expected type `w' (a rigid variable) against inferred type `Bool' `w' is bound by the polymorphic type `forall w. (ToggleButtonClass w) => w -> IO ()' at FG.hs:562:54-92 Expected type: w -> IO () Inferred type: Bool -> IO () In the first argument of `ToggleButtonP', namely `(toggleButtonSetActive p)' In the expression: ToggleButtonP (toggleButtonSetActive p) FG.hs:587:67: Couldn't match expected type `w' (a rigid variable) against inferred type `Bool' `w' is bound by the polymorphic type `forall w. (CheckButtonClass w) => w -> IO ()' at FG.hs:587:53-90 Expected type: w -> IO () Inferred type: Bool -> IO () In the first argument of `CheckButtonP', namely `(toggleButtonSetActive p)' In the expression: CheckButtonP (toggleButtonSetActive p)

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ANN: Yampa + GADT for ghc 6.6
by Joel Reymont 08 Jan '07

08 Jan '07

Folks, This is a raw version of cabalized Yampa + GADT for ghc 6.6. darcs get http://wagerlabs.com/yampa I would like to change the layout of the directory tree and I think there should be a single Cabal file that builds the source, tests and examples. I'm not sure if this is possible, though, as examples and tests depend on the library itself. Regardless, please send your comments and patches and in the meantime just follow the regular Cabal procedure in src, tests and examples. Thanks, Joel -- http://wagerlabs.com/

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Literate Haskell source files. How do I turn them into something I can read?
by Michael T. Richter 07 Jan '07

07 Jan '07

I'm trying to wrap my mind around the darcs source code as a preliminary to looking into GHC's guts. All of darcs is written as .lhs files which have bizarre mark-up in them which distracts me from the actual Haskell source I'm trying to figure out and get used to. Apparently the GHC compiler can take .lhs files, strip them with "unlit" (a utility which I finally found buried deep in the GHC installation -- off-path) and then compile them normally. The problem I have is that unlit leaves behind instead these huge gaping (and highly distracting) stretches of whitespace while it takes out the markup. Are there any tools which I can use to render .lhs files readable? I'm fine with having them converted into documented source (i.e. source code embedded in documentation) or as pure Haskell source (but without the huge whitespace gaps) -- but I can't figure out how to get either. -- Michael T. Richter Email: ttmrichter(a)gmail.com, mtr1966(a)hotpop.com MSN: ttmrichter(a)hotmail.com, mtr1966(a)hotmail.com; YIM: michael_richter_1966; AIM: YanJiahua1966; ICQ: 241960658; Jabber: mtr1966(a)jabber.cn "I think it is very beautiful for the poor to accept their lot [...]. I think the world is being much helped by the suffering of the poor people." --Mother Theresa

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Why does the wiki search facility not work properly?
by Brian Hulley 07 Jan '07

07 Jan '07

Hi, There is a page on the Haskell Wiki titled "Talk:SantaClausProblem" subtitled "Beautiful concurrency". However typing any of the following into the search box *doesn't* lead to the page: Santa talk:santaclausproblem beautiful beautiful concurrency Talk:Santa In fact to get the page you have to type the *exact* full title in the *exact* case. Luckily I could always refer back to SimonPJ's post to the Haskell mailing list to find the link to the page, but I think this situation is really bad because it means that things on the wiki are more or less just being thrown down a gaping void never to be seen again unless you know which catagories to look in from the main page. Another point is that the word "beautiful" does occur on the page but the page is not included in the list of page text matches. Perhaps the site is not being automatically re-indexed frequently enough? There is also a bunch of check boxes at the bottom of the search results page that doesn't seem to do anything either except cause nothing at all to happen when you click search unless the (Main) box is the only box ticked. Anyway I thought I'd just point this out in case anyone knows how to fix it. Thanks, Brian. -- http://www.metamilk.com

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less than helpful GHC error message
by Nicolas Frisby 07 Jan '07

07 Jan '07

Consider the terminal session at the bottom of this message. The extra "xc" in Test.hs was the result of me missing CTRL during an Emacs command (I'm guessing...). Unfortunately this took 30 minutes to find since I had far more than two modules and the error message doesn't point this out. Sure it's a silly mistake to make, but I'm guessing it's pretty common. I'm running GHC 6.6 on a PPC Mac. I know pragmas are wierd things, but could this error message be improved? Thanks, Nick $ head -n 10000 Main.hs Test.hs ==> Main.hs <== module Main where import Test main = test ==> Test.hs <== xc{-# OPTIONS -fglasgow-exts #-} module Test where test = putStrLn "weee" $ ghc --make Main <no location info>: file name does not match module name `Main'

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build error with happy-1.15 on ghc-6.6
by Yang 07 Jan '07

07 Jan '07

per a previous thread, i addressed the 'package lang not found' issue by changing the following lines to: $ grep -rsn '\blang\b' . | grep Makefile ./happy/src/Makefile:27:SRC_HC_OPTS += #-package lang ./happy/tests/Makefile:62:HC_OPTS += -fglasgow-exts # -package lang however i still get a build error, seemingly from LALR.lhs: /usr/local/bin/ghc -H16m -O -cpp -fglasgow-exts -O -c LALR.lhs -o LALR.o -ohi LALR.hi LALR.lhs:626:34: Not in scope: `bounds' i wasn't able to find 'bounds' defined in any other of the src files. thanks in advance for any help.

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Re: [Haskell-cafe] Seeking advice on a style question
by Steve Schafer 07 Jan '07

07 Jan '07

On Tue, 26 Dec 2006 20:21:45 -0800, you wrote: >How would this example look if you named only multiply-used expressions? >I'd like to see it in a more conventional pointful style with nested >expressions. I'm still wondering whether the awkwardness results from your >writing style or is more inherent. Showing the real variable names may also >help also. This is what it looks like "for real": > process :: Item -> MediaKind -> MediaSize -> Language -> SFO > process item mediaKind mediaSize language = > let pagemaster = loadPagemaster item mediaKind mediaSize; > questions = stripUndisplayedQuestions mediaKind $ > appendEndQuestions item pagemaster $ > coalesceParentedQuestions $ > validateQuestionContent $ > loadQuestions item; > (numberedQuestions,questionCategories) = numberQuestions pagemaster questions; > numberedQuestions' = coalesceNAQuestions numberedQuestions; > (bands,sequenceLayouts) = buildLayout mediaKind language numberedQuestions'; > bands' = resolveCrossReferences bands; > groupedBands = groupBands bands'; > pages = paginate item mediaKind mediaSize pagemaster groupedBands; > pages' = combineRows pages; > sfo = pages' sequenceLayouts; > in sfo These are the function signatures: > loadPagemaster :: Item -> MediaKind -> MediaSize -> Pagemaster > loadQuestions :: Item -> [Question] > validateQuestionContent :: [Question] -> [Question] > coalesceParentedQuestions :: [Question] -> [Question] > appendEndQuestions :: Item -> Pagemaster -> [Question] -> [Question] > stripUndisplayedQuestions :: MediaKind -> [Question] -> [Question] > numberQuestions :: Pagemaster -> [Question] -> ([NumberedQuestion],[QuestionCategory]) > coalesceNAQuestions :: [NumberedQuestion] -> [NumberedQuestion] > buildLayout :: MediaKind -> Language -> [NumberedQuestion] -> ([Band],[SequenceLayout]) > resolveCrossReferences :: [Band] -> [Band] > groupBands :: [Band] -> [[Band]] > paginate :: Item -> MediaKind -> MediaSize -> Pagemaster -> [[Band]] -> [Page] > combineRows :: [Page] -> [Page] > createSFO :: [Page] -> [SequenceLayout] -> SFO MediaKind, MediaSize and Language are simple enumerations; everything else is a complex structure. Steve Schafer Fenestra Technologies Corp. http://www.fenestra.com/

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