- Hugs-Users - Haskell.org

Can't find Preclude
by Forest Liu 16 Sep '06

16 Sep '06

I am a totally new user to haskell and hugs. I am working on Mac OS X 10.4.7(intel), and compile the hugs src myself(configure, make, make install), and than generate the hugs under /usr/local/bin and /usr/local/lib/hugs normally. When I launch hugs, it does not display "reading Preclude.hs" or like as the book describes. When I am running some simple programs from the book "Haskell: The Craft of Functional Programming", the error occurs to say cannot find 'ord', 'chr', or 'fromInt' and so on what I think should be defined in Preclude. But 'max' and 'min' goes correctly. I try to 'import Preclude' at the start line in the program, it says cannot find module Preclude. And I tried other packages, also cannot be found. Generally, I can't find where to load Preclude.hs manually or automately at startup. -- Sincerely, Forest Liu(��S)

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Re: [Haskell] xml-rpc in hugs
by Ross Paterson 08 Sep '06

08 Sep '06

[redirecting to hugs-users] On Fri, Sep 08, 2006 at 03:30:11PM +0500, David Tolpin wrote: > I'm trying to use xmlrpc module with hugs. The problems are not really > related to this particulare module, so the question is here. > > A module generated from the DTD for XML-RPC by HaXml contains import in > the following form: > > import Prelude (all, maybe, (++)) > > or something like that to avoid name conflicts with types of the same name > defined in the module. In Hugs it leads to (:) not being imported into the > module. Is there a way to import just (:) from the Prelude? Is there a way > to import all but some symbols from some module? Is (:) a data constructor? The (:) thing is a documented bug in Hugs: it should be special, but Hugs incorrectly treats it like a user-defined data constructor name. To make it also work with Hugs, you have to use the alternative form import Prelude hiding (various, conflicting, names)

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[noob] Typing error with nested list and tuple pattern?
by Peter Arrenbrecht 07 Sep '06

07 Sep '06

Hi all I am baffled by the following error message from Hugs 98 (Version May 2006): ERROR file:.\cube.hs:11 - Type error in explicitly typed binding *** Term : [(i,v) : ps] *** Type : [[(a,b)]] *** Does not match : [(Int,Double)] when attempting to compile the following declaration (line numbers in brackets): [10] test :: [(Int, Double)] -> Int [11] test [(i,v):ps] = i Is this a bug? If not, how do I write the pattern properly? Thanks, Peter Arrenbrecht -- View this message in context: http://www.nabble.com/-noob--Typing-error-with-nested-list-and-tuple-patter… Sent from the Haskell - Hugs-Users forum at Nabble.com.

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Pattern match failure leads to lots of output
by Neil Mitchell 02 Sep '06

02 Sep '06

Hi, Sometimes I get a pattern match error, with output such as: pattern match failure: uniqueHite_v9935 (instEq_v280 (instEq_v20 instEq_v11) (instEq_v20 instEq_v11)) (map head [[]] ++ (map_v810 (map (uniqueHite_v9931 (instOrd_v21 instOrd_v12))) (mapMaybe (uncurry equalGiven) (map_v810 (IFunc_Func "map~1" [0] (IExpr_Case (IExpr_Var 0) [("[]",IExpr_Make "[]" []),(":",IExpr_Make ":" [IExpr_Apply (IExpr_Lambda [1] IExpr_Unknown) [IExpr_Sel (IExpr_Var 0) "hd"],IExpr_Call "map~2" [IExpr_Sel (IExpr_Var 0) "tl"]])]) [],) (_SEL (,) (select_v1958 (foldr (select (groupSetExtract_v7750 (Make.Eq (instEq_v20_v1493 instEq_v11) (Eq_v481 (Make.Eq (instEq_v20_v1493 instEq_v11) (Eq_v481 (Make.Eq (instEq_v20_v1493 instEq_v11) (Eq_v481 (Make.Eq (instEq_v20_v1493 instEq_v11) (Eq_v481 (Make.Eq (instEq_v20_v1493 instEq_v11) (Eq_v481 (Make.Eq (instEq_v20_v1493 instEq_v11) (Eq_v481 (Make.Eq (instEq_v20_v1493 instEq_v11) (Eq ... Where the output goes on forever. This is unfortunate, because having sped up the screen printing of WinHugs quite considerably, now its a race to hit the stop button before this stuff has taken up the whole screen buffer (100Kb) and pushed the name of the function causing the error off the top. I guess the cause of this error is dictionary transformations resulting in a nested dictionary? Is there any way to stop this happening? Is it a known bug - it happens reasonably regularly to me. Thanks Neil

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[Fwd: Re: [Hugs-users] FW: [hugs-users-owner@haskell.org: Hugs & SOEGraphics]]
by Paul Hudak 26 Aug '06

26 Aug '06

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FW: [hugs-users-owner@haskell.org: Hugs & SOEGraphics]
by Simon Marlow 23 Aug '06

23 Aug '06

Dear Hugs Folk, Could someone reply to Bjorn's message below? Cheers, Simon -----Original Message----- From: mailman-bounces(a)haskell.org [mailto:mailman-bounces@haskell.org] On Behalf Of Bjorn Lisper Sent: 22 August 2006 12:44 To: hugs-users-owner(a)haskell.org Subject: [hugs-users-owner(a)haskell.org: Hugs & SOEGraphics] Hi, I sent a mail to hugs-users(a)haskell.org and I got the following automated reply. If this mailing list is indeed closed, then please remove the text at http://cvs.haskell.org/Hugs/pages/downloading.htm which says "To ask a question about using Hugs, please send a message to hugs-users(a)haskell.org". I simply followed the advice there. Please then also advise me how to obtain an answer to my simple question below. Best regards, Björn ------- Start of forwarded message ------- X-Sieve: CMU Sieve 2.2 Subject: Hugs & SOEGraphics From: hugs-users-owner(a)haskell.org To: lisper(a)it.kth.se Content-Type: multipart/mixed; boundary="===============1537646779==" Date: Tue, 22 Aug 2006 02:57:13 -0400 Precedence: bulk X-BeenThere: hugs-users(a)haskell.org X-Mailman-Version: 2.1.5 List-Id: The Hugs Users Mailing List <hugs-users.haskell.org> X-List-Administrivia: yes Sender: hugs-users-bounces(a)haskell.org X-Virus-Scanned: by amavisd-new at kth.se X-Spam-Status: No, hits=-5.2 tagged_above=-200.0 required=5.0 tests=BAYES_00, KTH_MAILMAN_HEADER_1, KTH_MAILMAN_HEADER_2, NO_REAL_NAME X-Spam-Level: You are not allowed to post to this mailing list, and your message has been automatically rejected. If you think that your messages are being rejected in error, contact the mailing list owner at hugs-users-owner(a)haskell.org. X-Original-To: hugs-users(a)haskell.org Date: Tue, 22 Aug 2006 09:08:59 +0200 (MEST) From: Bjorn Lisper <lisper(a)it.kth.se> To: hugs-users(a)haskell.org Subject: Hugs & SOEGraphics X-Virus-Scanned: by amavisd-new at kth.se Hi, My course in functional programming is just about to start. I use Paul Hudak's textbook "The Haskell School of Expression", and the SOE software. Does this software work with the latest version of Hugs (May 2006), or do we have to use the version that is provided via the SOE download page? (That version has some problems: for instance, winhugs does not work properly, so it would be nice if we could use the fresh Hugs version in the course.) Best regards, Björn Lisper Dept. of Computer Science and Electronics Mälardalen University P.O. Box 883 SE-721 23 Västerås Sweden Phone: +46-21-151709, Mobile: +46-70-6729577, Fax: +46-21-101460 (Phone KTH: +46-8-7904126) Email: bjorn.lisper(a)mdh.se WWW: http://www.idt.mdh.se/~blr/ -=- MIME -=- --===============1537646779== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit You are not allowed to post to this mailing list, and your message has been automatically rejected. If you think that your messages are being rejected in error, contact the mailing list owner at hugs-users-owner(a)haskell.org. --===============1537646779== Content-Type: message/rfc822 MIME-Version: 1.0 Return-Path: <lisper(a)it.kth.se> X-Original-To: hugs-users(a)haskell.org Delivered-To: hugs-users(a)haskell.org Received: from mx2.kth.se (mx2.kth.se [130.237.48.98]) by www.haskell.org (Postfix) with ESMTP id 739A0324141 for <hugs-users(a)haskell.org>; Tue, 22 Aug 2006 02:57:12 -0400 (EDT) Received: from localhost (localhost.localdomain [127.0.0.1]) by mx2.kth.se (Postfix) with ESMTP id 6FBD7141F51 for <hugs-users(a)haskell.org>; Tue, 22 Aug 2006 09:09:00 +0200 (CEST) Received: from mx2.kth.se ([127.0.0.1]) by localhost (mx2.kth.se [127.0.0.1]) (amavisd-new, port 10024) with LMTP id 30910-01-9 for <hugs-users(a)haskell.org>; Tue, 22 Aug 2006 09:08:59 +0200 (CEST) Received: from ripper.it.kth.se (ripper.it.kth.se [130.237.212.25]) by mx2.kth.se (Postfix) with ESMTP id 60B54142065 for <hugs-users(a)haskell.org>; Tue, 22 Aug 2006 09:08:59 +0200 (CEST) Received: (from lisper@localhost) by ripper.it.kth.se (8.12.10+Sun/8.12.11/Submit) id k7M78xh6020953; Tue, 22 Aug 2006 09:08:59 +0200 (MEST) Date: Tue, 22 Aug 2006 09:08:59 +0200 (MEST) Message-Id: <200608220708.k7M78xh6020953(a)ripper.it.kth.se> From: Bjorn Lisper <lisper(a)it.kth.se> To: hugs-users(a)haskell.org Subject: Hugs & SOEGraphics X-Virus-Scanned: by amavisd-new at kth.se Hi, My course in functional programming is just about to start. I use Paul Hudak's textbook "The Haskell School of Expression", and the SOE software. Does this software work with the latest version of Hugs (May 2006), or do we have to use the version that is provided via the SOE download page? (That version has some problems: for instance, winhugs does not work properly, so it would be nice if we could use the fresh Hugs version in the course.) Best regards, Björn Lisper Dept. of Computer Science and Electronics Mälardalen University P.O. Box 883 SE-721 23 Västerås Sweden Phone: +46-21-151709, Mobile: +46-70-6729577, Fax: +46-21-101460 (Phone KTH: +46-8-7904126) Email: bjorn.lisper(a)mdh.se WWW: http://www.idt.mdh.se/~blr/ --===============1537646779==-- ------- End of forwarded message -------

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Excerpt from "Yet another Haskell Tutorial"
by aldirithms＠gmx.net 07 Aug '06

07 Aug '06

Hello, (and sorry for the preceding accidental empty message), I'd like to ask a question concerning a following passage in "Yet another Haskell Tutorial" that ushers in the topic of monads: <<After all, suppose you have a function that reads a string from the keyboard. Ifyou call this function twice, and the user types something the first time and something else the second time, then you no longer have a function, since it would return two different values.>> How do I have to interpret this? I cannot make sense of it for I do not see where the definition of a function that I know is violated. I view it that way: The string is just a kind of argument to the string-reading function and that different strings (i.e. different arguments) yield different return values is a commonplace phenomenon with functions, isn't it? How do I have to alter this (over?)simple interpretation to see the point the author wants to make? Thank you very much in advance. Christian -- Echte DSL-Flatrate dauerhaft für 0,- Euro*. Nur noch kurze Zeit! "Feel free" mit GMX DSL: http://www.gmx.net/de/go/dsl

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Typing the plus operator
by aldirithms＠gmx.net 06 Aug '06

06 Aug '06

Hello Hugs Users, do you know why Hugs> :t 1 1 :: Num a => a and therefore Hugs> 1 :: Num a => a 1 is possible under Hugs, whereas Hugs> :t (+) (+) :: Num a => a -> a -> a and (not?) therefore Hugs> (+) :: Num a => a -> a -> a ERROR - Cannot find "show" function for: *** Expression : (+) *** Of type : Integer -> Integer -> Integer yields the error message shown? Thank you very much, Christian, Haskell beginner -- "Feel free" – 10 GB Mailbox, 100 FreeSMS/Monat ... Jetzt GMX TopMail testen: http://www.gmx.net/de/go/topmail

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Excerpt from"Yet another Haskell Tutorial"
by aldirithms＠gmx.net 05 Aug '06

05 Aug '06

-- Der GMX SmartSurfer hilft bis zu 70% Ihrer Onlinekosten zu sparen! Ideal für Modem und ISDN: http://www.gmx.net/de/go/smartsurfer

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natural numbers
by aldirithms＠gmx.net 03 Aug '06

03 Aug '06

Hello, thanks a lot for the expeditious replies to my trifling question. Here is another one: Can you tell me why the following does not function? I mean the last part for converting number into the new data type. If this is not a quick fix, please ignore it. As an utter beginner, I cannot estimate the significance of my questions. data Nat = Zero | Succ Nat natToInt Zero = 0 natToInt (Succ n) = (natToInt n) + 1 number n = case n of 0 -> Zero _ -> Succ(number(n-1)) Thank you very much. -- "Feel free" – 10 GB Mailbox, 100 FreeSMS/Monat ... Jetzt GMX TopMail testen: http://www.gmx.net/de/go/topmail

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