[Haskell-cafe] GHC Out of memory
I get an out-of-memory error about two thirds of the way through building qtHaskell. If I start again, the remaining modules are compiled successfully, although GHC's memory usage creeps up to about 1.5Gb by the time it's finished. Is there a memory leak? (Compiling on Win64 with 4Gb RAM.) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Cabal-install is broken
On Mon, Nov 22, 2010 at 4:16 PM, Permjacov Evgeniy wrote: > current cabal-install (0.8.2) cannot be compiled with ghc-7.0.1 set of > boot libraries. It requires cabal 1.8.* wich fails to compile. Does > anyone worked this out ? On some of my development environments I've been using the development version of cabal-install. On others, I stick to the Haskell Platform, which does not yet support GHC 7. It's a real pain to get cabal-install going on GHC 7, as you need to install all of the dependencies of cabal-install by hand. The next release of the platform is in January, with an RC is December[1]. Antoine [1] http://trac.haskell.org/haskell-platform/wiki/ReleaseTimetable ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Cabal-install is broken
current cabal-install (0.8.2) cannot be compiled with ghc-7.0.1 set of boot libraries. It requires cabal 1.8.* wich fails to compile. Does anyone worked this out ? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Re: Reply-To: Header in Mailinglists
On Sun, 2010-11-21 at 08:24 +, Malcolm Wallace wrote: > > If the mailing list replaced Reply-To header it would required > > additional effort for responders instead of just pressing reply-to- > > all. > > If the list were to add a "Reply-To:" header, but only in the case > where one was not already present, that would seem to me to be ideal. > (None of the internet polemics against Reply-To that I have seen, have > considered this modest suggestion.) > Except... I don't use Reply-To because it defaults to sender so it will still be breaking the RFC - in most cases (as most people don't set the Reply-To header). Regards signature.asc Description: This is a digitally signed message part ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Build problems with HDBC-mysql on the Mac
Dear cafe, Following the instructions at http://matt.freels.name/2010/hdbc-mysql-os-x.html I successfully installed HDBC-mysql on my Mac! However when doing a "cabal install" in a local package which depends on HDBC-mysql, cabal proceeds to reinstall HDBC-mysql (is this a bug? see my other email from a few moments ago), this time unsuccessfully because it is using the unpatched cached version downloaded from hackage. This breaks my installation: ghc-pkg list colors the package red. Now comes the weird part. :-) I try to reinstall HDBC-mysql with my unpacked, patched version. It fixes my installation of HDBC-again, even though it exits prematurely with some errors! I've included the output at the end of this email. I wonder: Where do these errors suddenly come from? The first time the installation went without trouble. How come it fixes my installation even though it reports errors? Thank you in advance, Martijn. Output of "cabal install --extra-lib-dirs=/usr/local/lib:" in a local version of HDBC-mysql, patched according to http://matt.freels.name/2010/hdbc-mysql-os-x.html: Resolving dependencies... [1 of 1] Compiling Main ( Setup.lhs, dist/setup/Main.o ) Setup.lhs:8:0: Warning: In the use of `findProgramOnPath' (imported from Distribution.Simple.Program): Deprecated: "use findProgramLocation instead" Linking ./dist/setup/setup ... Configuring HDBC-mysql-0.6.3... Preprocessing library HDBC-mysql-0.6.3... Connection.hsc:23:19: error: mysql.h: No such file or directory Connection.hsc: In function ‘main’: Connection.hsc:166: error: ‘MYSQL_FIELD’ undeclared (first use in this function) Connection.hsc:166: error: (Each undeclared identifier is reported only once Connection.hsc:166: error: for each function it appears in.) Connection.hsc:170: error: expected specifier-qualifier-list before ‘MYSQL_FIELD’ Connection.hsc:170: error: expected ‘;’ before ‘)’ token Connection.hsc:170: error: expected statement before ‘)’ token Connection.hsc:171: error: expected specifier-qualifier-list before ‘MYSQL_FIELD’ Connection.hsc:171: error: expected ‘;’ before ‘)’ token Connection.hsc:171: error: expected statement before ‘)’ token Connection.hsc:172: error: expected specifier-qualifier-list before ‘MYSQL_FIELD’ Connection.hsc:172: error: expected ‘;’ before ‘)’ token Connection.hsc:172: error: expected statement before ‘)’ token Connection.hsc:173: error: expected specifier-qualifier-list before ‘MYSQL_FIELD’ Connection.hsc:173: error: expected ‘;’ before ‘)’ token Connection.hsc:173: error: expected statement before ‘)’ token Connection.hsc:174: error: expected specifier-qualifier-list before ‘MYSQL_FIELD’ Connection.hsc:174: error: expected ‘;’ before ‘)’ token Connection.hsc:174: error: expected statement before ‘)’ token Connection.hsc:175: error: expected specifier-qualifier-list before ‘MYSQL_FIELD’ Connection.hsc:175: error: expected ‘;’ before ‘)’ token Connection.hsc:175: error: expected statement before ‘)’ token Connection.hsc:203: error: ‘MYSQL_BIND’ undeclared (first use in this function) Connection.hsc:210: error: expected specifier-qualifier-list before ‘MYSQL_BIND’ Connection.hsc:210: error: expected ‘;’ before ‘)’ token Connection.hsc:210: error: expected statement before ‘)’ token Connection.hsc:211: error: expected specifier-qualifier-list before ‘MYSQL_BIND’ Connection.hsc:211: error: expected ‘;’ before ‘)’ token Connection.hsc:211: error: expected statement before ‘)’ token Connection.hsc:212: error: expected specifier-qualifier-list before ‘MYSQL_BIND’ Connection.hsc:212: error: expected ‘;’ before ‘)’ token Connection.hsc:212: error: expected statement before ‘)’ token Connection.hsc:213: error: expected specifier-qualifier-list before ‘MYSQL_BIND’ Connection.hsc:213: error: expected ‘;’ before ‘)’ token Connection.hsc:213: error: expected statement before ‘)’ token Connection.hsc:214: error: expected specifier-qualifier-list before ‘MYSQL_BIND’ Connection.hsc:214: error: expected ‘;’ before ‘)’ token Connection.hsc:214: error: expected statement before ‘)’ token Connection.hsc:215: error: expected specifier-qualifier-list before ‘MYSQL_BIND’ Connection.hsc:215: error: expected ‘;’ before ‘)’ token Connection.hsc:215: error: expected statement before ‘)’ token Connection.hsc:216: error: expected specifier-qualifier-list before ‘MYSQL_BIND’ Connection.hsc:216: error: expected ‘;’ before ‘)’ token Connection.hsc:216: error: expected statement before ‘)’ token Connection.hsc:228: error: ‘MYSQL_TIME’ undeclared (first use in this function) Connection.hsc:232: error: expected specifier-qualifier-list before ‘MYSQL_TIME’ Connection.hsc:232: error: expected ‘;’ before ‘)’ token Connection.hsc:232: error: expected statement before ‘)’ token Connection.hsc:233: error: expected specifier-qualifier-list before ‘MYSQL_TIME’ Connection.hsc:233: error: expected ‘;’ before ‘)’ token Connection.hsc:233: error:
Re: [Haskell-cafe] Wondering if this could be done.
Haskell does not play as well with overloading as one would do it in C++; every name used must be fully qualified. Indeed, if we try something like Indeed, if we try something like data A = A Int deriving (Show, Eq) test = A 3 unA (A i) = i class Group a where (+) :: a -> a -> a instance Group A where (+) x y = A $ unA x + unA y we will get Ambiguous occurrence `+' It could refer to either `Main.+', defined at .hs:7:1 or `Prelude.+', imported from Prelude Failed, modules loaded: none. Haskell has its own brand of 'overloading': type classes. Every (+) sign used assumes that the operands are of the Num typeclass in particular. In order to define (+) on something else you will need to instance the Num typeclass over your A type. I am not sure what you mean by "the stuff defined in class Num is meanless to A." Strictly speaking nothing needs to be defined in a typeclass declaration other than the required type signatures. To instance the Num typeclass with A, though, assuming that A constructors take something that works with Num, you would do something similar to what Miguel posted: data A = A Int deriving (Show, Eq) test = A 3 unA (A i) = i instance Num A where (+) x y = A $ (unA x) + (unA y) (-) x y = A $ (unA x) - (unA y) (*) x y = A $ (unA x) * (unA y) abs x = A $ (unA $ abs x) signum y = A $ (unA $ signum y) fromInteger i = A (fromInteger i) Look at fromInteger, which must take Integer as as argument. That may be inconvenient for you. The Awesome Prelude, referenced in Chris's post, is a way of defining less specific version of basic types like Bool so that you have more choices in defining things like fromInteger in the Num typeclass (which must take an Integer; it is 'sad' if that Integer refers to a grounded, specific type). Still, if not every one of the Num operations make sense for your A type, you can leave them blank and get a warning. On Sun, Nov 21, 2010 at 10:48 PM, Magicloud Magiclouds < magicloud.magiclo...@gmail.com> wrote: > Hi, > For example, I have a data A defined. Then I want to add (+) and (-) > operators to it, as a sugar (compared to addA/minusA). But * or other > stuff defined in class Num is meanless to A. So I just do: > (+) :: A -> A -> A > (+) a b = > A (elem1 a + elem1 b) (elem2 a + elem2 b) -- I got errors here, for > the (+) is ambiguous. > > So, just wondering, does this way work in Haskell? > -- > 竹密岂妨流水过 > 山高哪阻野云飞 > ___ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Derived type definition
Sure, it's possible with TypeFamilies. The following compiles OK:
{-# LANGUAGE TypeFamilies #-}
module TypeCalc where
data Rec a r = Rec a r
data RecNil = RecNil
data Wrapper a = Wrapper a
class TypeList t where
type Wrapped t
i :: t -> Wrapped t
instance TypeList RecNil where
type Wrapped RecNil = RecNil
i RecNil = RecNil
instance TypeList r => TypeList (Rec a r) where
type Wrapped (Rec a r) = Rec (Wrapper a) (Wrapped r)
i (Rec a r) = Rec (Wrapper a) (i r)
type TTest = Rec Int (Rec String RecNil)
type TTestWrapped = Rec (Wrapper Int) (Rec (Wrapper String) RecNil)
a :: TTest
a = Rec 1 (Rec "a" RecNil)
f :: TTestWrapped -> (Int, String)
f (Rec (Wrapper n) (Rec (Wrapper s) RecNil)) = (n, s)
r = f (i a) -- so, "i a" is of the type TTestWrapped.
On 22 Nov 2010, at 23:43, kg wrote:
> Hi,
>
> I've tried to simplify as much as possible my problem. Finally, I think I can
> resume it like that:
>
> Suppose these following data types :
> data Rec a r = Rec a r
> data RecNil = RecNil
> data Wrapper a = Wrapper a
>
> Then, we can build the following type:
> type TTest = Rec Int (Rec String RecNil)
> or this type:
> type TTestWrapped = Rec (Wrapper Int) (Rec (Wrapper String) RecNil)
>
> Is it possible to build TTestWrapped from TTest ?
>
>
> Thx in advance,
> Antoine.
>
> ___
> Haskell-Cafe mailing list
> Haskell-Cafe@haskell.org
> http://www.haskell.org/mailman/listinfo/haskell-cafe
>
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Why does cabal unnecessarily reinstall dependencies?
On 23 November 2010 08:26, Martijn van Steenbergen wrote: > Hello cafe, > > When I want to locally install my own package through "cabal install" it > tries to reinstall dependencies convertible-1.0.9.1, HDBC-2.2.6.1 and > HDBC-mysql-0.6.3 even though they are already installed (and work fine). Why > does it do this? 1) Does "ghc-pkg check" complain about them? If so, it will rebuild them. 2) Do you mean it rebuilds the same version or a different/older version? 3) Did you build those packages with any compile-time flags, constraints, etc.? If so, I believe cabal-install defaults to wanting to rebuild them with the default settings. I believe that if you want to stop cabal-install from rebuilding non-broken packages, that unpacking what you want to install and then running "cabal install" within that directory (as opposed to doing "cabal install foo") is meant to work. -- Ivan Lazar Miljenovic ivan.miljeno...@gmail.com IvanMiljenovic.wordpress.com ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Why does cabal unnecessarily reinstall dependencies?
Hello cafe, When I want to locally install my own package through "cabal install" it tries to reinstall dependencies convertible-1.0.9.1, HDBC-2.2.6.1 and HDBC-mysql-0.6.3 even though they are already installed (and work fine). Why does it do this? cabal-install version 0.8.2 using version 1.8.0.2 of the Cabal library Mac OS Leopard Thanks, Martijn. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] looking for tagsoup-parsec examples
On Mon, Nov 22, 2010 at 02:20:22PM -0200, José Romildo Malaquias wrote: > > I am looking for some examples of code using Text.HTML.TagSoup.Parsec, > from the tagsoup-parsec package. In an attempt to learn how to use tagsoup together with parsec in order to do web scrapping, I rewrote the application that displays the Haskell.org hit count, explained in the "Drinking TagSoup by Example" tutorial [1]. The source code is attached. First I tried to use tagsoup-parsec [2], but it was not too helpful. Therefore I wrote a few parser combinators myself (inspired by tagsoup-parsec, and the "TagSoup, meet Parsec!" blog post [3]. I am posting the program here so that other Haskell programmers can comment on it. I would like also to do some suggestions to the author of tagsoup-parsec: a) export more functions, like tagEater, which may be needed in order to define new parsers or parser combinators; I needed them, but they were no usable because they are not exported; b) add more basic parsers and parser combinators (at least the ones I have defined in my program). c) add some examples d) use parsec version 3 [1] http://community.haskell.org/~ndm/darcs/tagsoup/tagsoup.htm [2] http://hackage.haskell.org/package/tagsoup-parsec [3] http://therning.org/magnus/archives/367 Regards, Romildo module Main (main) where import Text.Parsec hiding (satisfy) import Text.HTML.TagSoup (parseTags, Tag(TagText), (~==)) import Text.HTML.Download (openURL) import Data.Char (isDigit) import Data.List (findIndex) main = do src <- openURL "http://www.haskell.org/haskellwiki/Haskell"; let x = tagParse counter (parseTags src) putStrLn $ "haskell.org has been hit " ++ show x ++ " times" counter = do skipTo (tag "") count 2 (skipTo (tag "")) s <- tagText "" let ss = words s case findIndex (== "times.") ss of Just i -> let num = ss !! (i - 1) in return (read (filter isDigit num) :: Int) Nothing -> parserZero -- -- tag parser library -- tagParse p ts = either ( error . show ) id $ parse p "tagsoup" ts tagEater matcher = tokenPrim show (\pos t ts -> incSourceLine pos 1) matcher anyTag = tagEater Just satisfy f = tagEater (\t -> if f t then Just t else Nothing) tag t = satisfy (~== t) show t tagText str = do TagText x <- tag (TagText str) return x skipTo p = try p <|> (anyTag >> skipTo p) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Derived type definition
Hi, I've tried to simplify as much as possible my problem. Finally, I think I can resume it like that: Suppose these following data types : data Rec a r = Rec a r data RecNil = RecNil data Wrapper a = Wrapper a Then, we can build the following type: type TTest = Rec Int (Rec String RecNil) or this type: type TTestWrapped = Rec (Wrapper Int) (Rec (Wrapper String) RecNil) Is it possible to build TTestWrapped from TTest ? Thx in advance, Antoine. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] looking for tagsoup-parsec examples
Hello. I am looking for some examples of code using Text.HTML.TagSoup.Parsec, from the tagsoup-parsec package. Romildo ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Re: Reply-To: Header in Mailinglists
On 2010-11-21 08:24 +, Malcolm Wallace wrote: > If the list were to add a "Reply-To:" header, but only in the case > where one was not already present, that would seem to me to be ideal. > (None of the internet polemics against Reply-To that I have seen, have > considered this modest suggestion.) This still breaks the reply-to-author feature. > In the past, I have carefully used the Reply-To header to direct > responses to a particular mailing list of many (e.g. when cross- > posting an announcement). Yet because there is a culture of "Reply- > To: is bad", and most MUAs do not have a "ReplyToList" option, most > respondents end up pushing "Reply to all", which ignores my setting of > "Reply-To:", and spams more people than necessary. MUAs will honour the Reply-To header when using the reply-to-all function: the problem is that Reply-To does not mean what you think it means. The header indicates where *you* want to receive replies. So the reply-to-all function will reply to *you* (by using the value in Reply-To), and to everyone else by copying the To and Cc lists. There is another header, Mail-Followup-To, which tells MUAs to also drop the To and CC lists. I know several posters to this very list use it. However, it needs to be used with care because it can fragment cross- list discussions and/or prevent non-subscribers from receiving messages. -- Nick Bowler, Elliptic Technologies (http://www.elliptictech.com/) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GUI Designer
On 18 November 2010 20:28, c8h10n4o2 wrote: > > Or how to use XRC files with wxHaskell? > There are sample files in the wxHaskell distribution. If you can wait a day or two I will have a step-by-step blog article, but it's not quite finished yet. Regards Jeremy > -- > View this message in context: > http://haskell.1045720.n5.nabble.com/GUI-Designer-tp3271441p3271441.html > Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com. > ___ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Berlin Haskell Meeting
The next haskell meeting in Berlin will be this wednesday: Date: Wednesday, November 24th Time: from 20:00 Location: c-base, Rungestrasse 20, 10179 Berlin Hope to see you there, Sönke ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GUI Designer
On 18.11.10 21:28, c8h10n4o2 wrote: > There's a tutorial on how to use qtDesigner with qtHaskell ? sorry, i don't know of any tutorial, but there are some examples in the `examples' directory of the source distribution (e.g. tetrix.hs). basically you load the ui file, retrieve named widgets and attach signal handlers in haskell. signals and slots of compatible types can also be connected directly in Designer. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Wondering if this could be done.
Sure, you can define your own type class like that: import Prelude hiding ((+), (-)) -- usual (+) and (-) shouldn't be here... import qualified Prelude as P -- but they still are accessible with a prefix class Group a where (+) :: a -> a -> a (-) :: a -> a -> a instance Group Integer where (+) = (P.+) (-) = (P.-) instance Group A where (+) a b = A (elem1 a + elem1 b) (elem2 a + elem2 b) -- works for elem1 and elem2 being of class Group - say, Integer's (-) a b = ... 22.11.2010 9:48, Magicloud Magiclouds пишет: Hi, For example, I have a data A defined. Then I want to add (+) and (-) operators to it, as a sugar (compared to addA/minusA). But * or other stuff defined in class Num is meanless to A. So I just do: (+) :: A -> A -> A (+) a b = A (elem1 a + elem1 b) (elem2 a + elem2 b) -- I got errors here, for the (+) is ambiguous. So, just wondering, does this way work in Haskell? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
