Re: [Haskell-cafe] Proof in Haskell
> "Daniel" == Daniel Fischer writes: Daniel> On Tuesday 21 December 2010 19:34:11, Felipe Almeida Lessa wrote: >> > Theorem mirror_mirror : forall A (x : Tree A), mirror (mirror x) = x. >> induction x; simpl; auto. rewrite IHx1; rewrite IHx2; trivial. >> Qed. Daniel> Since mirror (mirror x) = x doesn't hold in Haskell, I take Daniel> it that Coq doesn't allow infinite structures? Why doesn't it hold? -- Colin Adams Preston Lancashire () ascii ribbon campaign - against html e-mail /\ www.asciiribbon.org - against proprietary attachments ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] "Haskell is a scripting language inspired by Python."
> "David" == David Fox writes: David> On Thu, Nov 4, 2010 at 2:41 PM, Albert Y. C. Lai wrote: >> On 10-11-03 10:00 PM, Jonathan Geddes wrote: >> >> It's called "The *Ultimate* Computer Language Guide," and it's on the >>> internets, so it must be correct, right? >> >> The correct conclusion: it's on the internets, so it must be LOL. David> The stuff that is *not* on the internets must be really David> awesome - can anyone give me a link to that? ://nearly.ubiquitous.org -- Colin Adams Preston Lancashire () ascii ribbon campaign - against html e-mail /\ www.asciiribbon.org - against proprietary attachments ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] A rant against the blurb on the Haskell front page
> "Don" == Don Stewart writes: >> Let me explain. >> >> "Haskell is an advanced purely functional programming language." >> >> Good start, if only the "advanced" were replaced with something >> more characteristic, like "lazy", or "statically typed". Which, >> BTW, both do not Don> "lazy" and "statically typed" don't mean much to other Don> people. They are buzz words that mean nothing to many people. And "purely functional programming language"? If they mean anything to many people, it's that the language works (i.e. functions). What language wouldn't work? I think Ben has a strong point here. -- Colin Adams Preston Lancashire () ascii ribbon campaign - against html e-mail /\ www.asciiribbon.org - against proprietary attachments ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Lambda-case / lambda-if
> "Max" == Max Bolingbroke writes: Prelude> (if then "Haskell" else "Cafe") False Max> "Cafe" My reaction is to ask: Can you write this as: (if then else) False "Haskell" "Cafe" ? -- Colin Adams Preston Lancashire () ascii ribbon campaign - against html e-mail /\ www.asciiribbon.org - against proprietary attachments ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ANNOUNCE: AbortT-transformers version 1.0
> "Henning" == Henning Thielemann writes: Henning> On Wed, 8 Sep 2010, Gregory Crosswhite wrote: > ExceptionT is a different matter because it handles "fail" as an >> uncaught error and places no restrictions on the error type, so >> one could implement the same functionality as AbortT by using >> ExceptionalT and requiring the end result be a monadic value of >> type "ExceptionalT e m e", where the exception and result types >> are the same. However, I believe that it is better to have the >> AbortT functionality available as a separate simple library >> specialized for this purpose than to have its functionality >> buried inside a more general library that is really intended to >> be used for a different purpose. Henning> If we get rid of the notion of an exception as being Henning> something bad, and instead consider an exception as being Henning> early exit for whatever reason, I see no problem. E.g. you Henning> may well use an exception to terminate a successful search, Henning> returning the search result as exception value. So where is the exceptional nature? Is a successful conclusion to a search so exceptional? It seems to me that you want to get rid of the notion of an exception as something exceptional, in which case it would be better to give it a different name. -- Colin Adams Preston Lancashire () ascii ribbon campaign - against html e-mail /\ www.asciiribbon.org - against proprietary attachments ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: String vs ByteString
> "Johan" == Johan Tibell writes: Johan> On Tue, Aug 17, 2010 at 1:36 PM, Tako Schotanus wrote: Johan> Yeah, I tried looking it up but I could find the Johan> technical definition for Char, but in the end I found that Johan> "maxBound" was "0x10" making it basically 24 bits :) Johan> I think that's enough to represent all the assigned Unicode Johan> code points. I also think the Unicode consortium (or whatever Johan> it is called) made some statement about the maximum number of Johan> bits they'll ever use. Yes. And UTF-16 is only capable of dealing with codepoints up to this limit. -- Colin Adams Preston Lancashire () ascii ribbon campaign - against html e-mail /\ www.asciiribbon.org - against proprietary attachments ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: String vs ByteString
> "Ivan" == Ivan Lazar Miljenovic writes: > Char is not an encoding, right? Ivan> No, but in GHC at least it corresponds to a Unicode codepoint. I don't think this is right, or shouldn't be right, anyway.. Surely it stands for a character. Unicode codepoints include non-characters such as the surrogate codepoints used by UTF-16 to map non-BMP codepoints to pairs of 16-bit codepoints. I don't think you ought to be able to see a surrogate codepoint as a Char. -- Colin Adams Preston Lancashire () ascii ribbon campaign - against html e-mail /\ www.asciiribbon.org - against proprietary attachments ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: String vs ByteString
> "Ketil" == Ketil Malde writes: Ketil> Johan Tibell writes: >> It's not clear to me that using UTF-16 internally does make >> Data.Text noticeably slower. Ketil> I think that *IF* we are aiming for a single, grand, unified Ketil> text library to Rule Them All, it needs to use UTF-8. Ketil> Alternatively, we can have different libraries with different Ketil> representations for different purposes, where you'll get Ketil> another few percent of juice by switching to the most Ketil> appropriate. Why not instead allow the programmer to decide at the function level which internal encoding to use? -- Colin Adams Preston Lancashire () ascii ribbon campaign - against html e-mail /\ www.asciiribbon.org - against proprietary attachments ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: String vs ByteString
> "Bryan" == Bryan O'Sullivan writes: Bryan> On Sat, Aug 14, 2010 at 10:46 PM, Michael Snoyman wrote: Bryan> When I'm writing a web app, my code is sitting on a Linux Bryan> system where the default encoding is UTF-8, communicating Bryan> with a database speaking UTF-8, receiving request bodies in Bryan> UTF-8 and sending response bodies in UTF-8. So converting all Bryan> of that data to UTF-16, just to be converted right back to Bryan> UTF-8, does seem strange for that purpose. Bryan> Bear in mind that much of the data you're working with can't Bryan> be readily trusted. UTF-8 coming from the filesystem, the Bryan> network, and often the database may not be valid. The cost of Bryan> validating it isn't all that different from the cost of Bryan> converting it to UTF-16. But UTF-16 (apart from being an abomination for creating a hole in the codepoint space and making it impossible to ever etxend it) is slow to process compared with UTF-32 - you can't get the nth character in constant time, so it seems an odd choice to me. -- Colin Adams Preston Lancashire () ascii ribbon campaign - against html e-mail /\ www.asciiribbon.org - against proprietary attachments ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Suggestions For An Intro To Monads Talk.
> "Alexander" == Alexander Solla writes: Alexander> On Aug 3, 2010, at 2:51 PM, aditya siram wrote: > I am looking for suggestions on how to introduce the concept and its >> implications. I'd also like to include a section on why monads >> exist and why we don't really see them outside of Haskell. Alexander> Start with functors (things that attach Alexander> values/functions/functors to values in an algebra). Move Alexander> on to applicative functors (functors that can interpret Alexander> the thing that is getting things attached to it). Move Alexander> on to monads Too late! The audience has already dozed off. Alexander> (applicative functors where you can Alexander> explicitly control the order of Alexander> evaluation/interpretation). -- Colin Adams Preston Lancashire () ascii ribbon campaign - against html e-mail /\ www.asciiribbon.org - against proprietary attachments ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Can we come out of a monad?
> "Kevin" == Kevin Jardine writes: Kevin> The more I learn about monads, however, the less I understand Kevin> them. I've seen plenty of comments suggesting that monads Kevin> are easy to understand, but for me they are not. I used to have the same problem. Then I read: http://ertes.de/articles/monads.html and after that it was very clear. -- Colin Adams Preston Lancashire () ascii ribbon campaign - against html e-mail /\ www.asciiribbon.org - against proprietary attachments ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] DTP10 Call for Participation
> "Conor" == Conor McBride writes: Conor> Remember, Haskell is the world's most popular dependently Conor> typed functional programming language... Could you justify that claim please? -- Colin Adams Preston Lancashire () ascii ribbon campaign - against html e-mail /\ www.asciiribbon.org - against proprietary attachments ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell and the Software design process
> "aditya" == aditya siram writes: aditya> This is awesome! GHC-devs , please mainline the CONTRACT aditya> pragma. I think it needs a LOT more work before it is usable. (I hope I'm wrong, but Dana reckoned it needed about 7 more man-years of work.) Dana sent me a copy of her ghc 6.8 repository (which didn't compile), and I updated (by hand) a 6.11 repository. I was able to get a few test programs to be rejected as not fulfilling their contracts (due to type classes), and a few others to loop at compile time, but I couldn't find any that passed. I was supposed to have a go at debugging the loops, but never got round to it. -- Colin Adams Preston Lancashire () ascii ribbon campaign - against html e-mail /\ www.asciiribbon.org - against proprietary attachments ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Hackage accounts and real names
> "Pekka" == Pekka Enberg writes: Pekka> On Tue, Apr 6, 2010 at 7:32 AM, Ivan Miljenovic Pekka> wrote: >> 5) No-one is convincing anyone else to their point of view, so we >> have a stale mate. Pekka> Can you really legally distribute your software under an open Pekka> source license if you don't use your real name? Well, yes, you can. The FSF has always suggested that you can assign the copyright of your GPL'ed software to them, in some circumstances. Note I'm very much pro the real-name policy in principle, but I don't see how it can be enforced. -- Colin Adams Preston Lancashire () ascii ribbon campaign - against html e-mail /\ www.asciiribbon.org - against proprietary attachments ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] chp-plus doesn't install
> "Neil" == Neil Brown writes: Neil> That did indeed turn out to be the fix. That will teach me to Neil> release a package without remembering to test it on GHC 6.10 Neil> first. I've uploaded chp-plus 1.2.0 to Hackage, which should Neil> fix this issue (among other changes). So: Neil> cabal update && cabal install chp-plus Neil> Should work now. Let me know if you have any other troubles. Yes, I was able to compile and run the first program in the tutorial. Thanks. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] chp-plus doesn't install
I'm getting these errors (ghc 6.10.4 on Linux x86_64): Building chp-plus-1.1.0... [1 of 9] Compiling Control.Concurrent.CHP.Test ( Control/Concurrent/CHP/Test.hs, dist/build/Control/Concurrent/CHP/Test.o ) [2 of 9] Compiling Control.Concurrent.CHP.Console ( Control/Concurrent/CHP/Console.hs, dist/build/Control/Concurrent/CHP/Console.o ) [3 of 9] Compiling Control.Concurrent.CHP.Connect ( Control/Concurrent/CHP/Connect.hs, dist/build/Control/Concurrent/CHP/Connect.o ) Control/Concurrent/CHP/Connect.hs:146:67: Couldn't match expected type `ChanOpts a' against inferred type `ConnectableParam (Chanout a)' In the first argument of `oneToOneChannel'', namely `o' In the second argument of `(<$>)', namely `oneToOneChannel' o' In the first argument of `(>>=)', namely `((writer &&& reader) <$> oneToOneChannel' o)' Control/Concurrent/CHP/Connect.hs:152:67: Couldn't match expected type `ChanOpts a' against inferred type `ConnectableParam (Chanin a)' In the first argument of `oneToOneChannel'', namely `o' In the second argument of `(<$>)', namely `oneToOneChannel' o' In the first argument of `(>>=)', namely `((reader &&& writer) <$> oneToOneChannel' o)' etc. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Internet game servers in Haskell?
Has anyone ever written a server in Haskell for managing live game-playing (any game) across the internet? -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Parallel Pi
> "Ketil" == Ketil Malde writes: Ketil> I think the general consensus was a 10-15% speedup from HT. I used to see 3-core performance from my twin hyper-threaded Xeons, when running C compiles (i.e. 50% speed-up). -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Haskell and XML, need some tips from practioners
> "Günther" == Günther Schmidt writes: Günther> Dear Alistair, after working intensely with XSLT again Günther> (with a break for several years), I wholeheartedly concur. Günther> You guys are right though, through the document function it Günther> would be possible. Günther> So any particular tool-set you could recommend? Saxon is by far the best, if you're happy with a java program. (I can hardly recommend my own. Not through modesty, of which I am not over-endowed, but because I refuse to support it since the W3C abolished the concept of XML as self-describing data.) -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell and XML, need some tips from practioners
> "Günther" == Günther Schmidt writes: Günther> But now I need to amend the attributes of some elements Günther> with looked up values from the outside, the lookup-key is a Günther> particular attribute value of the nodes. This I cannot do Günther> through xslt processing as the information needed is not Günther> within the xml document. You probably can. Via implementing some custom URI resolver, or an extension function, or such like. Depending upon the xslt implementation. Not that I'm discouraging you from doing it in Haskell instead. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: haskelldb in-memory driver?
> "Günther" == Günther Schmidt writes: Günther> Hello Johannes, no, sorry, HaskellDB is only meant for RDBM Günther> back ends, it eventually generates SQL (Strings). I recall that there WAS an experimental in-memory backend. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Stack ADT?
> "Casey" == Casey Hawthorne writes: Casey> You could also implement stacks with mutable data structures, Casey> e.g. STArray, etc. Casey> What do you want to use a stack ADT for? BTW, There is a Myers stack in Edison. Disclaimer - I don't know what a Myers stack is. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: programmatic DB interface?
> "Johannes" == Johannes Waldmann writes: >> That is exactly the problem - it is wrong for CalendarT. Johannes> what do you mean by "it" ... what package should be fixed Johannes> (old-locale, haskelldb-hdbc-postgreqsl, ...)? Because Johannes> obviously something seems broken here. "It" is the use of unzoned times. I sent the following patch to the haskelldb list several months ago. But there has not been a new release since then. Colin> It is just the code to generate the SQL for CREATE TABLE is Colin> presumably faulty. For CalendarTimeT columns it should Colin> generate a time of Colin> timestamp with time zone Colin> as CalendarTime is a zoned timestamp. here's my patch: --- Default.hs~ 2009-02-13 23:06:25.0 + +++ Default.hs 2009-10-01 16:43:34.0 +0100 @@ -92,7 +92,7 @@ IntegerT -> SqlType "bigint" DoubleT -> SqlType "double precision" BoolT -> SqlType "bit" - CalendarTimeT -> SqlType "timestamp" + CalendarTimeT -> SqlType "timestamp with time zone" BStrT a -> SqlType1 "varchar" a -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: programmatic DB interface?
> "Johannes" == Johannes Waldmann writes: Johannes> Michael Snoyman snoyman.com> writes: >> Did you append an empty string in the SELECT statement? Johannes> Magnus says 1. is wrong, but I don't see how the DB server Johannes> could be convinced to send the ...T...Z format. In my Johannes> application, the table definition contains 'timestamp Johannes> without time zone' and I cannot change that. That is exactly the problem - it is wrong for CalendarT. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: programmatic DB interface?
> "Johannes" == Johannes Waldmann writes: Johannes> anyone know what's happening here? I get this when Johannes> executing a query via haskelldb-hdbc-postgresql-0.12 (The Johannes> date is actually in the DB, so it's not a connection Johannes> problem.) Johannes> Convertible: error converting source data SqlString Johannes> "2008-10-29 00:00:00" of type SqlValue to type Johannes> Data.Time.LocalTime.LocalTime.LocalTime: Cannot parse Johannes> using default format string "%Y-%m-%dT%T%Q" I had this sort of problem. I sent a patch on the haskell-db list to use UTC - I believe the release behaviour is incorrect. You might check the list archives, as they have a better memory than I. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] HTML - based GUIs - follow up
> "Günther" == Günther Schmidt writes: Günther> My question is: do formlets only work server based or is it Günther> also possible to use formlet sans happs? Yes (I think) and yes. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Language simplicity
> "Roel" == Roel van Dijk writes: Roel> I think it is time for an Obfuscated Haskell Contest :-) Are you allowed to use obsolete scripts for your identifiers? :-) -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Language simplicity
> "Tom" == Tom Tobin writes: Tom> readability. The ASCII characters are universal and easily Tom> recognized No they are not. My wife is Chinese. When she was learning pinyin as a child, she asked her father for help with some homework. He replied that he didn't understand them. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Language simplicity
> "Andrew" == Andrew Coppin writes: Andrew> It's weird that us Haskell people complain about there Andrew> being only 26 letters in the alphabet Which alphabet? You have plenty of choice in Unicode. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Allowing hyphens in identifiers
> "Daniel" == Daniel Fischer writes: Daniel> Database.Haskell_DB.Sql.Postgre_SQL Actually, I would be semi-happy with Database.Haskell-DB.Sql.Postgre-SQL (obviously we need an option whether to use hypens or underscores. I prefer hyphens.) Daniel> Data.Bits.shiftL Daniel> would that be preferred as Daniel> shiftL Daniel> shift_L Daniel> shift_l I think I prefer shift-left :-) I'd settle for the last. Daniel> Generally, when shall we flatten the hump, 1) always -- Daniel> not 2) unless followed by an uppercase letter 3) when Daniel> followed by a lowercase letter I'm nit sure. i think a more sophisticated rule might be needed. Daniel> feedO'Houlihan? Daniel> IMO, it should clearly go to feed_O'Houlihan Yes, I think so. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Allowing hyphens in identifiers
> "Daniel" == Daniel Fischer writes:
Daniel> As a pre-alpha version:
Daniel>
Daniel> module Main (main) where
Daniel> import Data.Char (isUpper, isLower, toLower)
Daniel> main :: IO () main = interact unCamel
Daniel> unCamel :: String -> String unCamel ('<':cs) = '<' : inTag
Daniel> cs unCamel (a:bs@(b:cs)) | isLower a && isUpper b = a :
Daniel> '_' : toLower b : unCamel cs | otherwise = a : unCamel bs
Daniel> unCamel cs = cs
Daniel> inTag :: String -> String inTag ('>':cs) = '>' : unCamel
Daniel> cs inTag (a:cs) = a : inTag cs inTag [] =
Daniel> []
Daniel> Compile, run with
Daniel> ./unCamel < /path/to/HaddockOutput.html >
Daniel> /path/to/Haddock_output.html
Daniel> (or whatever Windows uses to redirect stdin and stdout)
Daniel> This makes a few not-well-founded assumptions about
Daniel> haddock's output. Try it on a couple of files, report
Daniel> bugs.
I tried it.
I'm not all that happy with the resulting uncameling.
For instance,
Database.HaskellDB.Sql.PostgreSQL
goes to
Database.Haskell_dB.Sql.Postgre_sQL
which is uglier than before.
I.m not sure how I would write this going the other way, using
Richard's hspp pre-processor.
I'd want to write Database.Haskell_DB.Sql.Postgresql, but I'd guess
I'd have to write it as Database.Haskell_DB.Sql.Postgre_s_q_l or just
Database.Haskell_DB.Sql.PostgreSQL :-(
Anyway, I'm having trouble with using Richard hspp. It changes ok_url
to okUrl, but in fact the function concerned is named ok_url in
Network.URL, so the pre-processor would have to be applied as part of
cabal install for all packages.
I don't think it's practical to edit all the .cabal packages as they
come in to say:
ghc-options: -F -pgmF hspp
and cabal install does not recognize this line if I add to to my
~/.cabal/config file.
Duncan, is there a way this can be done?
--
Colin Adams
Preston Lancashire
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Re: [Haskell-cafe] Re: Allowing hyphens in identifiers
> "Ketil" == Ketil Malde writes: >> [1] and quite a high proportion of other natural languages. Ketil> Which makes me wonder - might there be a (natural) language Ketil> bias as well? Sure. Different languages have different orthographical traditions. IMHO a project should adopt the styles of the natural language it uses for comments (assuming that the project leader has mandated a language for comments). The Haskell standard libraries don't do this. There is also the question of whether a programming language should be adaptable to the natural language used in a project (e.g. spelling of keywords). I have tried to advocate that it should, several times in the past. But no-one has ever agreed with me on this. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Allowing hyphens in identifiers
> "Daniel" == Daniel Fischer writes: Daniel> Now, would you be interested in a transformation the other Daniel> way round, so that you can read other people's code in Daniel> your preferred style? I would, applied to the output of haddock, at least. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Re: Allowing hyphens in identifiers
> "Richard" == Richard O'Keefe writes: Richard> The real point is that the revised version, with command Richard> line arguments and all, is still just 52 SLOC. (41 if Richard> you don't count type specifications the compiler could Richard> have inferred or the two import directives.) This looks really good. When I first started writing Haskell seriously, just over a year ago, I wrote with underscores, but the mix of style caused by the standard library names was so disconcerting that IReluctantlySwitchedToHumpyIlliterateStyle (though not for comments, where I stuck to standard English punctuation). So I welcome this chance to switch to natural English style (hyphens). The main that puzzles me at the moment is how to write a cabal file. That is, I can specify the ghc options to invoke the preprocessor in the cabal file, but this supposes the compiled program is available on the system concerned. This won't necessarily be the case if I distribute code written in this style on hackage. So the answer seems to be to release this preprocessor on hackage, and then make it a dependcy. But can a library depend upon an executable program? looking at the Cabal users guide, I can't see anywhere that says it can't. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Allowing hyphens in identifiers
> "Malcolm" == Malcolm Wallace writes: >> there is enough experimentally determined about reading in >> general to be certain that visible gaps between words >> materially improves readability, and internal capital letters >> harm it. Malcolm> Here is a (slightly mischievous) proposal. Malcolm> Allow the Unicode non-breaking space character ( in Malcolm> HTML) as a valid character in a varid or conid. Malcolm> :-) I thought of that one too (seriously). It has the disadvantage that the syntax is ambiguous to the human eye without tool support (e.g. highlighting). On the other hand humans are good at coping with such ambiguity (we do it all the time in spoken language - and delight in puns. And in written language, set is indistinguishable from set, which is indistinguishable from set, which ... - to however many distinct meanings for the word set are currently recognized). -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Logistic regression
Is there any free code anywhere for performing logistic regression? I can't see anything on hackage. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Trouble installing HDBC 2.1.1 with ghc 6.10.4
I'm seeing messages such as: Database/HDBC/SqlValue.hs:610:32: No instance for (Typeable Day) Is this connected with the in-and-out status of the time library in the GHC 6.10.x series? Is there a work-around? -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Pattern Matching
> "Andrew" == Andrew Coppin writes: Andrew> Casey Hawthorne wrote: >> Why in a pattern match like >> >> score (1 3) = 7 >> >> can I not have >> >> sizeMax = 3 >> >> score (1 sizeMax) = 7 >> If I had a dollar for every time I've written something like Andrew> case msg of eVENT_QUIT -> ... eVENT_POST -> ... Andrew> eVENT_RESIZE -> ... Andrew> and spent an hour trying to figure out why the messages Andrew> aren't being processed right... ;-) So why aren't they? -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ANN: hesql
> "Christoph" == Christoph Bauer writes: Christoph> Hello, sure, your program could use a database with Christoph> HDBC. But I'll guess (since you love static typing so Christoph> much) you dislike formulating queries in strings and to Christoph> check the positions of your ?-placeholders and to Christoph> convert your values with fromSql/toSql. You guess right. That's why I use HaskellDB. Why would hesql be an improvement for me? It sounds like several steps backwards? -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell image libraries
> "Jeremy" == Jeremy Shaw writes: Jeremy> There is a partial binding to libgd: Jeremy> http://hackage.haskell.org/packages/archive/gd/3000.4.0/doc/html/Graphics-GD.html Jeremy> http://www.libgd.org/Main_Page Jeremy> But GD itself may not do what you want. I ended up using this myself, but it is an unsatisfactory compromise (no support for TIFF - and many other formats, trashes EXIF information). In my innocence I had imagined that GTK (the GIMP ToolKit) would provide all the image manipulation facilities that the GIMP offers. But no. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell image libraries
> "Max" == Max Rabkin writes: Max> Haskellers, To add image support to fdo-notify, I need an Max> image type. Looking through Hackage, I didn't find any image Max> library with the following features: * Load from a variety of Max> formats (at least PNG and JPG, I'd say) * Efficient per-pixel Max> access, or a way to dump the image into a ByteString as a Max> bitmap (I need to serialise them into the protocol's bitmap Max> format) Preferably, it should be possible to construct images Max> programmatically too. Max> Is there really no such library? It would be nice to have Max> something like a Haskell equivalent of the Python Imaging Max> Library, which is the de facto standard image library in Max> Python and supports just about every type of operation on Max> images you could ask for. I've found nothing either, having searched recently. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to fulfill the "code-reuse" destiny of OOP?
> "Magnus" == Magnus Therning writes: Magnus> It seems I was wrong in my assumption about "data Magnus> inheritance", "implementation inheritance" is just as Magnus> evil. Both are fine. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ANN: haskell-mode 2.5
> "Svein" == Svein Ove Aas writes: Svein> Known bugs: * Occasionally, the haskell-indentation parser Svein> will get stuck on what it considers to be invalid haskell Quite often. Svein> code, and refuse to accept your commands; this includes, Svein> mainly, haskell-newline-and-indent. To avoid annoyance, if Svein> you bind RET to haskell-newline-and-indent, you should bind I don't, but haskell-indentation.el does. Svein> M-RET to plain newline. So perhaps the mode should also do this? here's a patch: -- haskell-indentation.el~ 2009-10-27 19:27:40.0 + +++ haskell-indentation.el 2009-10-27 19:29:43.0 + @@ -67,7 +67,7 @@ (defconst haskell-indentation-mode-map (let ((keymap (make-sparse-keymap))) (define-key keymap [?\r] 'haskell-newline-and-indent) -(define-key keymap [?\M-r] 'newline) +(define-key keymap [?\M-\r] 'newline) (define-key keymap [backspace] 'haskell-indentation-delete-backward-char) (define-key keymap [?\C-d] 'haskell-indentation-delete-char) keymap)) -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] A 3 line program --> Reid, Don, Daniel
> "Brandon" == Brandon S Allbery KF8NH writes: Brandon> That would be the Haskell98 Report: Haskell uses the Brandon> Unicode [11] character set. However, source programs are Brandon> currently biased toward the ASCII character set used in Brandon> earlier versions of Haskell . Brandon> So yes, it's reasonable to "blame" the language (spec). Note also that it mentions the Unicode character set, not a particular Unicode encoding scheme. To me that implies that an implementation must support all 7 encoding schemes, not just UTF-8. At which point you probably want to make use of iconv, so you might as well support all iconv-supported encodings. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Libraries for Commercial Users
> "Magnus" == Magnus Therning writes: Magnus> Again, in my own experience the amount of work to find a Magnus> good developer is about the same, and sometimes stacked in Magnus> favour of using an obscure language. I would be inclined to agree with you. Coming from the other end, as someone who has spent the last 7 years as an Eiffel developer (Haskell is only something I can do in my spare time), I believe that the company I work for has no problem finding good Eiffel developers (or just good developers who can be expected to learn Eiffel quickly). I think the risk is rather on the developer than the company. Suppose the company I work for were to go under in the near future (in the current economic climate, that can't be ruled out). Since they are probably the last company employing any significant number of Eiffel developers, I would probably find it very difficult indeed to find another job as an Eiffel developer, so I would have to look elsewhere, encumbered by a CV that did not show recent work in popular languages. Probably the risk for Haskell developers would be less, since Haskell popularity is rising, rather than falling. But it is certainly a consideration I would have thought (not that I ever thought about it seriously when accepting an Eiffel job - I'm an enthusiast - though now more for Haskell). -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] why cannot i get the value of a IORef variable ?
> "Gregory" == Gregory Crosswhite writes: Gregory> Yes, I was once taught that "Every time you use Gregory> unsafePerformIO, God kills a kitten," so every time I Gregory> consider using it I first ask myself: is this really Gregory> worth an innocent kitten's life? I've changed my mind. Everyone go out and use unsafePerformIO all the time. That way we can get rid of all those mudering kittens, and the dragonflies will live longer. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] why cannot i get the value of a IORef variable ?
zaxis> thank you! In fact i really donot understand zaxis> "unsafePerformIO" very much ! Then all you have to understand is - never use it! -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] What *is* a DSL?
>>>>> "Gregg" == Gregg Reynolds writes: Gregg> On Thu, Oct 8, 2009 at 6:08 AM, Colin Paul Adams Gregg> wrote: > >>>>> "George" == George Pollard writes: >> George> I'd also like to note that the canonical pronunciation of George> DSL ends in "-izzle". >> >> Whose canon? >> >> Interestingly, I have always assumed the canonical >> pronunciation of DSSSL was diesel, as JADE stands for JAmes's >> DSSSL Engine. >> >> I don't see why removing extra S-es should shorten the vowel. >> >> Wht vwl? U mst b Englsh. 2 n Amrcn, DSSSL is "dissel"; all >> short vowels. Certainly I am English, and so is James Clark. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] What *is* a DSL?
> "George" == George Pollard writes: George> I'd also like to note that the canonical pronunciation of George> DSL ends in "-izzle". Whose canon? Interestingly, I have always assumed the canonical pronunciation of DSSSL was diesel, as JADE stands for JAmes's DSSSL Engine. I don't see why removing extra S-es should shorten the vowel. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] dsl and gui toolkit
> "John" == John A De Goes writes: John> This is the right approach to a GUI toolkit. John> Note that personally, I believe the details of the John> presentation should be separate from Haskell, stored in a John> separate file that is machine- friendly, so designers can John> work in concert and in parallel with developers. Like CSS? -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Where do these warnings come from?
>>>>> "Anton" == Anton van Straaten writes:
Anton> Colin Paul Adams wrote:
>> Does anyone recognize which module/function would emit the
>> following warnings?
>>
>> WARNING: nonstandard use of escape in a string literal LINE 11:
>> '# Pandoc\r\n\r\nPandoc is a program for converting ... ^
>> HINT: Use the escape string syntax for escapes, e.g., E'\r\n'.
Anton> PostgreSQL. Perhaps you're trying to save that text in a
Anton> database?
Yes, thanks. I am.
Is it safe to just ignore the warnings, or do I need to run some
function over the strings before saving, and the reverse when restoring?
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[Haskell-cafe] Where do these warnings come from?
Does anyone recognize which module/function would emit the following warnings? WARNING: nonstandard use of escape in a string literal LINE 11: '# Pandoc\r\n\r\nPandoc is a program for converting ... ^ HINT: Use the escape string syntax for escapes, e.g., E'\r\n'. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ANNOUNCE: SourceGraph-0.5.0.0
>>>>> "Ivan" == Ivan Lazar Miljenovic writes:
Ivan> Colin Paul Adams writes: Compare
Ivan> the version in the subject to the version you're trying to
Ivan> install...
You are right. i forgot to do a cabal update first.
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Re: [Haskell-cafe] ANNOUNCE: SourceGraph-0.5.0.0
> "Ivan" == Ivan Lazar Miljenovic writes: Ivan> I'd appreciate it if people could give SourceGraph a whirl Fails to install (Linux x86_64): Data/Graph/Analysis/Utils.hs:207:43: Ambiguous occurrence `dotizeGraph' It could refer to either `Data.Graph.Analysis.Utils.dotizeGraph', defined at Data/Graph/Analysis/Utils.hs:199:0 or `Data.GraphViz.dotizeGraph', imported from Data.GraphViz at Data/Graph/Analysis/Utils.hs:81:0-19 Data/Graph/Analysis/Utils.hs:220:18: Not in scope: data constructor `PointList' cabal: Error: some packages failed to install: Graphalyze-0.5 failed during the building phase. The exception was: exit: ExitFailure 1 SourceGraph-0.3 depends on Graphalyze-0.5 which failed to install. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Comments requested: succ Java
> "Michael" == Michael Snoyman writes: Michael> not be written in pure Haskell, but then again I'm not Michael> sure if there are any fully W3 compliant browsers *not* Michael> written in C++. I'm not sure if there are any fully W3 compliant browsers. How could there be? It would mean consistent W3C recommendations. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Processing EXIF data with Haskell
> "Don" == Don Stewart writes: Don> colin: >> I'm writing web software for a photograph gallery. I want to be >> able to display selective fields from the EXIF data. I thought >> I would be able to use the GD and exif libraries from Hackage >> to do this. However: >> >> Calling Graphics.GD.loadJpegByteString followed by >> Graphics.GD.saveJpegFile does not preserve the EXIF fields of >> the uploaded file, but instead writes some new ones (many fewer >> fields than the original, and nothing of interest). >> >> Graphics.Exif.allTags shows an interesting subset of the >> original EXIF data, but nothing from the version saved by GD. >> >> Can anyone shed any light on any of this? Don> Contact the author, patch the library? I tried the former - no answer yet. Maybe just waiting a little will help. As for the latter, it's just a binding to a C library. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Processing EXIF data with Haskell
I'm writing web software for a photograph gallery. I want to be able to display selective fields from the EXIF data. I thought I would be able to use the GD and exif libraries from Hackage to do this. However: Calling Graphics.GD.loadJpegByteString followed by Graphics.GD.saveJpegFile does not preserve the EXIF fields of the uploaded file, but instead writes some new ones (many fewer fields than the original, and nothing of interest). Graphics.Exif.allTags shows an interesting subset of the original EXIF data, but nothing from the version saved by GD. Can anyone shed any light on any of this? -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] haskelldb + sqlite problem.
>>>>> "Colin" == Colin Paul Adams writes:
>>>>> "Magicloud" == Magicloud Magiclouds
>>>>> writes:
Magicloud> Hi, I am using haskelldb and
Magicloud> haskelldb-hdbc-sqlite3. Well, I finally got the source
Magicloud> compiled and ran, I got this error: App: user error
Magicloud> (SQL error: SqlError {seState = "", seNativeError = 21,
Magicloud> seErrorMsg = "prepare 74: SELECT subject,\n
Magicloud> timestamp\nFROM notes as T1\nORDER BY timestamp DESC:
Magicloud> library routine called out of sequence"}) Any clue what
Magicloud> I should check?
Colin> Did you get this working? If so, what was the problem and
Colin> how did you go about resolving it.
Colin> I have the identical problem. I had the database code
Colin> working fine, but then I added a state monad into the monad
Colin> stack for the program, and now I get this problem. I see
Colin> that John Goerzen suggested it might be a result of reading
Colin> the data lazily. So I tried changing my import statements
Colin> from import Control.Monad.State to import
Colin> Control.Monad.State.Strict
Colin> in case the StateT was indirectly causing the problem, but
Colin> that doesn't make any difference.
As I suspected, the problem is something to do with my putting the
Database.HaskellDB.Database.Database into the state monad, and getting
it from there, rather than passing it around explicitly. So I guess I
have too much laziness in:
ApplicationState db _ <- lift get
How do I force db in this situation?
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Re: [Haskell-cafe] haskelldb + sqlite problem.
> "Magicloud" == Magicloud Magiclouds
> writes:
Magicloud> Hi, I am using haskelldb and
Magicloud> haskelldb-hdbc-sqlite3. Well, I finally got the source
Magicloud> compiled and ran, I got this error: App: user error
Magicloud> (SQL error: SqlError {seState = "", seNativeError = 21,
Magicloud> seErrorMsg = "prepare 74: SELECT subject,\n
Magicloud> timestamp\nFROM notes as T1\nORDER BY timestamp DESC:
Magicloud> library routine called out of sequence"}) Any clue what
Magicloud> I should check?
Did you get this working? If so, what was the problem and how did you
go about resolving it.
I have the identical problem. I had the database code working fine,
but then I added a state monad into the monad stack for the program,
and now I get this problem.
I see that John Goerzen suggested it might be a result of reading the
data lazily.
So I tried changing my import statements from
import Control.Monad.State
to
import Control.Monad.State.Strict
in case the StateT was indirectly causing the problem, but that
doesn't make any difference.
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Re: [Haskell-cafe] happstack-helpers fails to install on Mac OSX
>>>>> "Colin" == Colin Paul Adams writes: >>>>> "Colin" == Colin Paul Adams writes: Colin> I've just installed the Haskell Platform (2009.2.0.2) on Colin> Mac OSX 10.5.6, including GHC 6.10.4. Colin> Then I started added some packahges with cabal install. Colin> But happstack-helpers-0.30 fails with: Colin> Happstack/Helpers/DirBrowse.hs:88:105 Couldn't match Colin> expected type `String' against inferred type `Bool' In the Colin> third argument of `hscolour', namely `False' In the second Colin> argument of `(.)', namely `BrowseHtmlString . (hscolour Colin> defaultColourPrefs False False f)' Colin> Is this a known error, and if so, is there a workaround? Colin> I guess it's the same problem that was reported earlier Colin> this week with hlint and hscolour 1.15. I'll try Colin> installing an earlier version of hscolour. Yes. Installing hscolour 1.14 instead did the trick. Can we have a new version of happstack-helpers that supports hscolour 1.15 please? -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] happstack-helpers fails to install on Mac OSX
>>>>> "Colin" == Colin Paul Adams writes: Colin> I've just installed the Haskell Platform (2009.2.0.2) on Colin> Mac OSX 10.5.6, including GHC 6.10.4. Colin> Then I started added some packahges with cabal install. Colin> But happstack-helpers-0.30 fails with: Colin> Happstack/Helpers/DirBrowse.hs:88:105 Couldn't match Colin> expected type `String' against inferred type `Bool' In the Colin> third argument of `hscolour', namely `False' In the second Colin> argument of `(.)', namely `BrowseHtmlString . (hscolour Colin> defaultColourPrefs False False f)' Colin> Is this a known error, and if so, is there a workaround? I guess it's the same problem that was reported earlier this week with hlint and hscolour 1.15. I'll try installing an earlier version of hscolour. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] happstack-helpers fails to install on Mac OSX
I've just installed the Haskell Platform (2009.2.0.2) on Mac OSX 10.5.6, including GHC 6.10.4. Then I started added some packahges with cabal install. But happstack-helpers-0.30 fails with: Happstack/Helpers/DirBrowse.hs:88:105 Couldn't match expected type `String' against inferred type `Bool' In the third argument of `hscolour', namely `False' In the second argument of `(.)', namely `BrowseHtmlString . (hscolour defaultColourPrefs False False f)' Is this a known error, and if so, is there a workaround? -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Problem with monadic formlets
Chris> Hey everybody, I've just uploaded formlets 0.6.1 to Chris> Hackage, which should fix this bug. Thanks for letting me Chris> know! Yes, it does fix it. Thanks. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Problem with monadic formlets
>>>>> "Colin" == Colin Paul Adams writes: >>>>> "Jeremy" == Jeremy Shaw writes: Colin> apparent data corruprion is occurring. I am suspecting a Colin> bug in the formlets library (I have version 0.6). Colin> So I have created a slightly cut-down (no database Colin> involved) complete working program. Can you see if this Colin> works ok with your version of formlets: I managed to uninstall formlets-0.6 myself, and then installed 0.5 instead. After adding the necessary extra argument to runFormletState (an empty string), the test program works fine. So this seems to be a bug in formlets-0.6. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Uninstall a cabal package?
> "Peter" == Peter Robinson writes: Peter> As far as I know the current stable release of Cabal Peter> doesn't keep track of installed packages, so you can only # Peter> ghc-pkg unregister pkg-id and then manually delete the Peter> files. Thanks. That works. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Uninstall a cabal package?
What is the procedure to uninstall a cabal package? -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Problem with monadic formlets
> "Jeremy" == Jeremy Shaw writes:
Jeremy> Hello, I hacked your code into a runnable example, and it
Jeremy> seems to work for me.
Jeremy> Which looks correct to me. Your code looks fine to me as
Jeremy> well... Perhaps the error is not in the code you pasted,
Jeremy> but somewhere else. I am running on an older, and somewhat
Jeremy> forked version of Formlets, so there could also be a bug
Jeremy> in the new code I guess. Though, that seems unlikely. But
Jeremy> it is worth noting that we are not using the same version
Jeremy> of the formlets library.
I did some debugging in ghci, but was unable to step through the
ensure and check routines, which is where the apparent data corruprion
is occurring. I am suspecting a bug in the formlets library (I have
version 0.6).
So I have created a slightly cut-down (no database involved) complete
working program. Can you see if this works ok with your version of
formlets:
module Main where
import Control.Applicative
import Control.Applicative.Error
import Control.Applicative.State
import Data.List as List
import Text.Formlets
import qualified Text.XHtml.Strict.Formlets as F
import qualified Text.XHtml.Strict as X
import Text.XHtml.Strict ((+++), (<<))
import Happstack.Server
type XForm a = F.XHtmlForm IO a
data Registration = Registration { regUser :: String
, regPass :: String }
deriving Show
handleRegistration :: ServerPartT IO Response
handleRegistration = withForm "register" register showErrorsInline (\u ->
okHtml $ regUser u ++ " is successfully registered")
withForm :: String -> XForm a -> (X.Html -> [String] -> ServerPartT IO
Response) -> (a -> ServerPartT IO Response) -> ServerPartT IO Response
withForm name frm handleErrors handleOk = dir name $ msum
[ methodSP GET $ createForm [] frm >>= okHtml
, withDataFn lookPairs $ \d ->
methodSP POST $ handleOk' $ simple d
]
where
handleOk' d = do
let (extractor, html, _) = runFormState d frm
v <- liftIO extractor
case v of
Failure faults -> do
f <- createForm d frm
handleErrors f faults
Success s -> handleOk s
simple d = List.map (\(k,v) -> (k, Left v)) d
showErrorsInline :: X.Html -> [String] -> ServerPartT IO Response
showErrorsInline renderedForm errors =
okHtml $ X.toHtml (show errors) +++ renderedForm
createForm :: Env -> XForm a -> ServerPartT IO X.Html
createForm env frm = do
let (extractor, xml, endState) = runFormState env frm
xml' <- liftIO xml
return $ X.form X.! [X.method "POST"] << (xml' +++ X.submit "submit" "Submit")
okHtml :: (X.HTML a) => a -> ServerPartT IO Response
okHtml content = ok $ toResponse $ htmlPage $ content
htmlPage :: (X.HTML a) => a -> X.Html
htmlPage content = (X.header << (X.thetitle << "Testing forms"))
+++ (X.body << content)
register :: XForm Registration
register = Registration <$> user <*> passConfirmed
user :: XForm String
user = pure_user `F.checkM` F.ensureM valid error where
valid name = return True
error = "Username already exists in the database!"
pure_user :: XForm String
pure_user = input `F.check` F.ensure valid error where
input = "Username" `label` F.input Nothing
valid = (>= 3) . length
error = "Username must be three characters or longer."
passConfirmed :: XForm String
passConfirmed = fst <$> passwords `F.check` F.ensure equal error where
passwords = (,) <$> pass "Password" <*> pass "Password (confirm)"
equal (a, b) = a == b
error = "The entered passwords do not match!"
pass :: String -> XForm String
pass caption = input `F.check` F.ensure valid error where
input = caption `label` F.password Nothing
valid = (>=6) . length
error = "Password must be six characters or longer."
label :: String -> XForm String -> XForm String
label l = F.plug (\xhtml -> X.p << (X.label << (l ++ ": ") +++ xhtml))
main = simpleHTTP (nullConf {port = 9959}) handleRegistration
--
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[Haskell-cafe] Problem with monadic formlets
I'm trying to validate user input against a database (using HaskellDB, but that doesn't seem to be the problem, as replacing the database monadic code with return True gives the same problem. This is part of my code: register :: Database -> XForm Registration --register db = Registration <$> pure_user <*> passConfirmed register db = Registration <$> (user db) <*> passConfirmed user :: Database -> XForm String user db = pure_user `F.checkM` F.ensureM valid error where valid name = do let q = do t <- table user_table restrict (t!user_name .==. constant name) return t rs <- query db q return $ null rs error = "Username already exists in the database!" pure_user :: XForm String pure_user = input `F.check` F.ensure valid error where input = "Username" `label` F.input Nothing valid = (>= 3) . length error = "Username must be three characters or longer." passConfirmed :: XForm String passConfirmed = fst <$> passwords `F.check` F.ensure equal error where passwords = (,) <$> pass "Password" <*> pass "Password (confirm)" equal (a, b) = a == b error = "The entered passwords do not match!" pass :: String -> XForm String pass caption = input `F.check` F.ensure valid error where input = caption `label` F.password Nothing valid = (>=6) . length error = "Password must be six characters or longer." If I uncomment the commented line, and comment out the line after it (in register), then everything works as expected. However, using it as it is, one of the calls to pass gets the user's name for validation (and consequently either fails if the user name is only 5 characters, or the comparison of the two passwords fail (unless I type the user name as the password). I thought the applicative style meant the effects did not influence one another, but here there is clear contamination. What am i doing wrong? -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Qualified operators
> "Miguel" == Miguel Mitrofanov writes: Miguel> firstArgument Cool.Module.Name.%-& secondArgument Thanks. I think I tried that first, must have have got misled by ghc's other confusing messages. Compiling ok now. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Qualified operators
What's the syntax for using a qualified operator (I have a clash of !)? -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Where does documentation get installed with cabal?
> "Antoine" == Antoine Latter writes: Antoine> On Thu, Aug 20, 2009 at 8:58 AM, Colin Paul Antoine> Adams wrote: >> Hello, >> >> I'm trying to find the API documentation for happstack 0.3 >> (online is for 0.2). >> >> So I did: >> >> cabal install happstack --reinstall --enable-documentation >> >> but I can't find it anywhere within ~/.cabal - where should I >> look? Antoine> Most of hasppstack functionality is not in the Antoine> "happstack" package, it's in the happstack-* packages. So Antoine> installing the happstack package with documentation won't Antoine> really pull in much documentation at all. Thanks. That was what I was missing. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Where does documentation get installed with cabal?
>>>>> "Max" == Max Desyatov writes: Max> Colin Paul Adams writes: >> I'm trying to find the API documentation for happstack 0.3 >> (online is for 0.2). >> >> So I did: >> >> cabal install happstack --reinstall --enable-documentation >> >> but I can't find it anywhere within ~/.cabal - where should I >> look? Max> In most cases it is installed in Max> ~/.cabal/share/doc/happstack*/html. Is there any files at Max> that directory? There are now, but only a very few. And very little contents in them. It's as if the --reinstall were partial. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Where does documentation get installed with cabal?
Hello, I'm trying to find the API documentation for happstack 0.3 (online is for 0.2). So I did: cabal install happstack --reinstall --enable-documentation but I can't find it anywhere within ~/.cabal - where should I look? -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] gbp sign showing as unknown character by GHC
> "Stuart" == Stuart Cook writes: Stuart> On Thu, Aug 20, 2009 at 4:28 PM, Colin Paul Stuart> Adams wrote: >> But how do you get Latin-1 bytes from a Unicode string? This >> would need a transcoding process. Stuart> The first 256 code-points of Unicode coincide with Stuart> Latin-1. Therefore, if you truncate Unicode characters Stuart> down to 8 bits you'll effectively end up with Latin-1 text Stuart> (except that any code points above U+00FF will give Stuart> strange results). Stuart> If your terminal then interprets these bytes as UTF-8 (or Stuart> anything else, really), the result will be gibberish or Stuart> worse. Yes, but surely this will work both ways. The same bytes on input should come back on output, shouldn't they? -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] gbp sign showing as unknown character by GHC
> "Bulat" == Bulat Ziganshin writes: Bulat> Hello Colin, Bulat> Thursday, August 20, 2009, 10:13:28 AM, you wrote: > I don't understand where latin-1 comes into this. String is supposed >> to be a list of Unicode characters. Bulat> but ghc 6.10 i/o used String as list of bytes But how do you get Latin-1 bytes from a Unicode string? This would need a transcoding process. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] gbp sign showing as unknown character by GHC
> "Judah" == Judah Jacobson writes: Judah> On Wed, Aug 19, 2009 at 10:31 AM, Iain Barnett wrote: >> Quick question: I've tested this in a couple of different >> terminals (roxterm and xterm), so I'm fairly sure it's GHC >> that's the problem. Have I missed a setting? GHCi, version >> 6.10.4 Prelude> putStrLn "£" >> � Hugs98 200609-3 Hugs> putStrLn "£" >> £ >> ghc-6.10.4 and earlier don't automatically encode/decode Unicode Judah> characters. So on terminals which don't use the latin-1 Judah> encoding, you need to do the conversion explicitly with a Judah> separate package such as utf8-string, iconv or text-icu. I don't understand where latin-1 comes into this. String is supposed to be a list of Unicode characters. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: ANN: Typeful/Text/HTMLs (for AngloHaskell/for scrap?)
> "Jon" == Jon Fairbairn writes: >> Will it be cabal-ized soon? Jon> That depends on whether anyone wants it done sufficiently Jon> strongly to do it. Then I guess I will - some time in October. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: ANN: Typeful/Text/HTMLs (for AngloHaskell/for scrap?)
> "Jon" == Jon Fairbairn writes: Jon> I wrote: >> You can get the whole thing with >> >> darcs get --partial >> http://homepage.ntlworld.com/jon.fairbairn/Typeful/Text/nHTMLs Jon> but that was a temporary url that I copied and pasted. The Jon> correct one: Jon> darcs get --partial Jon> http://homepage.ntlworld.com/jon.fairbairn/Typeful/Text/HTMLs Did you make any progress on this at Anglo-Haskell? Will it be cabal-ized soon? -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Planning for a website
>>>>> "Gour" == Gour writes: >>>>> "Colin" == Colin Paul Adams writes: Colin> So my major decision is what framework and html-generating Colin> libraries to use. There is such a wide choice on the Colin> Haskell Wiki. But I guess some are more maintained than Colin> others. For instance, WASH attracts me, with it's guarantee Colin> of valid generated pages, but it isn't clear to me that Colin> it's actively maintained (last date I can see on the web Colin> pages is 2006). Gour> Have you thought about Turbinado (http://turbinado.org) ? I didn't like it when I clicked on the link that says: Learn about Turbinado here and got a this page doesn't exist response. Then I looked at the archticeture link, and didn't like the idea of having to generate Haskell data types from relational tables (if i understood it right). I'd much rather be using happstack's macid stuff, especially as I will have only very low usage, so i shouldn't have any scalability problems. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Planning for a website
>>>>> "Jake" == Jake McArthur writes:
Jake> Colin Paul Adams wrote:
>> One problem will be to get GHC ported to DragonFly BSD, but
>> that can wait until I have a test version of the site working
>> on Linux.
Jake> I would love to see this. It's the biggest thing blocking me
Jake> from trying Dragonfly more seriously.
Well it will happen, as I have to use DragonFly, as my website is all
about dragonflies :-)
Someone has already got it working sufficiently to compile xmonad, so
it should just be a matter of digging around the low-level issues.
Jake> You should look into HSP. It also provides those guarantees,
Jake> is maintained, and provides a nice template-style syntax
Jake> which you can use inline with your Haskell code.
Jake> Also check out the Formlets library.
>> HappStack is obviously currently maintained, and since it seems
>> to have a blogging module in development, that is attractive.
Jake> I recommend this.
Thanks.
--
Colin Adams
Preston Lancashire
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[Haskell-cafe] Planning for a website
I'm intending to replace my current website - which uses Drupal, with a hand-written-in-Haskell version this autumn, for a number of reasons (a principal one is the lack of an upgrade path in Drupal). So I'm currently looking into the libraries available to see how much I'll have to write myself. One problem will be to get GHC ported to DragonFly BSD, but that can wait until I have a test version of the site working on Linux. The next major challange is to implement something like Drupal's Image and Image Gallery modules. That doesn't seem to be a great problem, as the exif and GD libraries seem to cover everything I'll need. So my major decision is what framework and html-generating libraries to use. There is such a wide choice on the Haskell Wiki. But I guess some are more maintained than others. For instance, WASH attracts me, with it's guarantee of valid generated pages, but it isn't clear to me that it's actively maintained (last date I can see on the web pages is 2006). HappStack is obviously currently maintained, and since it seems to have a blogging module in development, that is attractive. HASP is maintained too, I think. Has anyone written a comparison of the various libraries, or gone through the same decision process recently? -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Text.Html introduction
http://www.haskell.org/ghc/docs/latest/html/libraries/xhtml/Text-XHtml.html says: "Based on the original Text.Html library by Andy Gill. See http://www.cse.ogi.edu/~andy/html/intro.htm for an introduction to that library. " But that link gives a not-found page. Anyone know where it is know? -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Can't install Haskell Platform on 64-bit Linux
> "Magnus" == Magnus Therning writes: Magnus> Ouch, there only seems to be a version of 6.10.3 in Fedora Magnus> 11, if I read this correctly: Magnus> https://admin.fedoraproject.org/pkgdb/packages/name/ghc Magnus> (I'm not a Fedora user so I might be completely confused Magnus> here :-) Magnus> It looks like the pre-built ghc can't find the installed Magnus> libgmp. I don't think it's a problem with libgmp. I think that's just a cautionary message, based on experience that this is a common error. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Can't install Haskell Platform on 64-bit Linux
> "Magnus" == Magnus Therning writes: Magnus> On Tue, Aug 18, 2009 at 10:25 AM, Colin Paul Magnus> Adams wrote: >> I installed GHC 6.10.4 (as ./configure said it was required) >> from a .bz2 file on the GHC downloads page. I then tried >> ./configure for the platform again, and got: Magnus> What distribution of Linux do you use? Fedora. Magnus> I'd strongly suggest getting it from your distro's repo Magnus> rather than downloading the tar-ball. That way you avoid Magnus> satisfying dependencies manually. It's not available. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Can't install Haskell Platform on 64-bit Linux
I installed GHC 6.10.4 (as ./configure said it was required) from a .bz2 file on the GHC downloads page. I then tried ./configure for the platform again, and got: checking ghc actually works... no configure: error: Your installation of ghc does not appear to work. It cannot compile a simple program (see config.log for the details). If you installed ghc from a generic binary tarball then it is worth checking that you have the 'gmp' C library and header files installed. (On debian-based systems this package is called libgmp3-dev.) Looking in config.log, I see: configure:2287: checking ghc actually works configure:2296: /usr/local/bin/ghc -o conftest conftest.hs /tmp/ghc22651_0/ghc22651_0.s: Assembler messages: /tmp/ghc22651_0/ghc22651_0.s:43:0: Error: suffix or operands invalid for `push' /tmp/ghc22651_0/ghc22651_0.s:89:0: Error: suffix or operands invalid for `push' /tmp/ghc22651_0/ghc22651_0.s:135:0: Error: suffix or operands invalid for `push' configure:2299: $? = 1 configure: failed program was: main = putStr "Hello world!\n" -- this file generated by TRY-COMPILE-GHC end of failed program. configure:2308: result: no configure:2314: error: Your installation of ghc does not appear to work. It cannot compile a simple program (see config.log for the details). If you installed ghc from a generic binary tarball then it is worth checking that you have the 'gmp' C library and header files installed. (On debian-based systems this package is called libgmp3-dev.) Libgmp is installed. I don't know the significance of the assembler error messages. If I type from the command line: ghci I get the Prelude> prompt, so it looks like the installation is OK at first glance. What should I check next? -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Thinking about what's missing in our library coverage
> "Tom" == Tom Tobin writes: >> This can surely be tackled by cabal, as it already has the >> license information. Tom> I don't see this as a real solution; why would a package be It should be done anyway, irrespective of the platform. Tom> added to the platform in the first place if a large Tom> proportion of developers couldn't make use of it? Anyone can make use of it. You may choose not to (or your boss may choose for you), but that doesn't mean you can't. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Thinking about what's missing in our library coverage
> "Tom" == Tom Tobin writes: Tom> As I understand it, Pandoc is entirely under the GPL (not Tom> LGPL). I'd be very wary of accepting a GPL'd library as a I'd be very upset if pandoc weren't blessed. Tom> blessed "standard" library, since it would be completely Tom> unusable for non-GPL projects. This can surely be tackled by cabal, as it already has the license information. So if you were to specify you project has a BSD license, and it requires use of a library licensed under the GPL, then cabal configure should fail with an error message. Just because a library is blessed, doesn't mean you have to use it. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Proposal: TypeDirectedNameResolution
> "Ryan" == Ryan Ingram writes: Ryan> Along those lines, what about being able to elide class Ryan> names when they can be unambiguously determined from the Ryan> functions defined? Ryan> instance _ [] where fmap = map pure x = [x] fs <*> xs = [ f Ryan> x | f <- fs, x <- xs ] return x = [x] m >>= f = concatMap f Ryan> m Ryan> This would define Functor, Applicative, and Monad for []. What happens if I define a class Foo with a method named fmap? If this were in scope then Functor would no longer be defined for []. Could this situation cause a problem? -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to determine if a FilePath is a directory name or regular file?
> "Judah" == Judah Jacobson writes: Judah> On Sun, Jun 21, 2009 at 11:12 PM, Colin Paul Judah> Adams wrote: >> I've been hoogling like bad to try to determine if a function >> like this exists. >> >> getDirectoryContents returns sub-directories as well as file >> names. I want only the latter, so I'm looking for a suitable >> filter. Judah> Use System.Directory.doesDirectoryExist/doesFileExist. Thanks. it seems it's time i went to the optician again. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] How to determine if a FilePath is a directory name or regular file?
I've been hoogling like bad to try to determine if a function like this exists. getDirectoryContents returns sub-directories as well as file names. I want only the latter, so I'm looking for a suitable filter. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Can't install chp (confused by cabal yet again)
I tried a cabal install chp: It complained that base was hidden. So I unpacked the archive, and tried installing using runhaskell Setup configure/build/install. Now I get (from install): Setup: You need to re-run the 'configure' command. The version of Cabal being used has changed (was Cabal-1.6.0.3, now Cabal-1.6.0.2). So I repeated the process and get the same message again. ghc version is 6.10.3 Also: cabal --version cabal-install version 0.6.2 using version 1.6.0.2 of the Cabal library Where does this 1-6.0.3 come from (Ghc HEAD perhaps?)? What can I do about it? -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Can't install happs-tutorial because syb-with-class fails to install
False alarm. It compiles OK with ghc 6.10.3. The failure was with ghc 6.11.20090404. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Can't install happs-tutorial because syb-with-class fails to install
Data/Generics/SYB/WithClass/Derive.hs:187:26: Couldn't match expected type `Pred' against inferred type `Type' Expected type: PredQ Inferred type: TypeQ In the first argument of `map', namely `dataCxt' In the first argument of `(++)', namely `map dataCxt dataCxtTypes' Data/Generics/SYB/WithClass/Derive.hs:198:36: Couldn't match expected type `Pred' against inferred type `Type' Expected type: Q Pred Inferred type: TypeQ In the expression: conT 'Data `appT` typ In the first argument of `map', namely `(\ typ -> conT 'Data `appT` typ)' Data/Generics/SYB/WithClass/Derive.hs:227:38: Couldn't match expected type `Name' against inferred type `TyVarBndr' Expected type: [Name] Inferred type: [TyVarBndr] In the expression: ps In the first argument of `return', namely `(n, ps, map conA cs)' cabal: Error: some packages failed to install: syb-with-class-0.5.1 failed during the building phase. The exception was: exit: ExitFailure 1 -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] List of exports of a module - are there alternatives?
> "Andrew" == Andrew Wagner writes: Andrew> Uh, show me such a module, and I'll show you a module Andrew> that's quite bloated and desperately needs to be Andrew> refactored. How about a module that provides the official Unicode names for each character? -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: ANNOUNCE: Utrecht Haskell Compiler (UHC) -- first release
> "Lennart" == Lennart Augustsson writes: Lennart> Of course, n+k will be missed by Haskell obfuscators. I Lennart> mean, what will we do without (+) + 1 + 1 = (+) ? I think what would be missed would you be having the opportunity to explain to me what it means. But as we still have them, go right ahead (please). -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Link errors in Gtk2Hs are more general than I thought.
> "Jeff" == Jeff Wheeler writes: Jeff> I installed Gtk2Hs on a similar machine earlier tonight, Jeff> with much success, even with Yi. Jeff> I did not use MacPorts, and instead followed the Jeff> instructions on the HaskellWiki [1] under "Using the GTK+ OS Jeff> X Framework" (including compiling pkg-config from src). I'm Jeff> not sure how having attempted the installation through Jeff> MacPorts may have littered your system, unfortunately. A lot I think (I tried the Framework install once, and spent a LOT of time cleaning up, and the same when I reverted macports). -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Completely confused by cabal
>>>>> "Duncan" == Duncan Coutts writes: Duncan> On Sun, 2009-03-22 at 11:51 +, Colin Paul Adams wrote: >> >>>>> "Achim" == Achim Schneider writes: >> Achim> Colin Paul Adams wrote: > >> So why doesn't it find packages then, when they are installed? >> >> Achim> I've got no idea, what exactly are you trying to do, and Achim> how? >> >> I'm trying to re-compile ghc 6.11 and it doesn't find parsec. Duncan> The ghc build system is fairly self contained. I'm not Duncan> sure if it cares if your bootstrapping compiler has parsec Duncan> or not. If the ghc build system is looking for the parsec Duncan> modules then I very much doubt it is going to be looking Duncan> in any parsec package that your bootstrapping compiler Duncan> might have registered (either globally or per-user). It'll Duncan> be looking for the sources that it comes bundled with. Duncan> A quick look in my ghc source tree reveals: Duncan> ghc/utils/ext-core/Language/Core/ParsecParser.hs Duncan> ghc/libraries/parsec/Text/ParserCombinators/Parsec.hs Duncan> The first one, utils/ext-core is importing parsec. Is that Duncan> what you're trying to build? The parsec package is an No. I assumed that would be built anyway. Duncan> extralib so wouldn't be present unless you did ./darcs-all Duncan> --extra get Duncan> If you can't get the ghc build going try asking on the ghc Duncan> users mailing list. Give as much detail as you can about Duncan> what you did so people can give you more helpful advice. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Completely confused by cabal
>>>>> "Andrea" == Andrea Vezzosi writes: Andrea> On Sun, Mar 22, 2009 at 12:51 PM, Colin Paul Adams Andrea> wrote: >>>>>>> "Achim" == Achim Schneider writes: >> >> Achim> Colin Paul Adams wrote: >> >> So why doesn't it find packages then, when they are >> installed? >> Achim> I've got no idea, what exactly are >> you trying to do, and Achim> how? >> >> I'm trying to re-compile ghc 6.11 and it doesn't find parsec. Andrea> when cabal is invoked by root, like in su -c "cabal ..." Andrea> or su -c "runghc Setup ...", it won't see the user Andrea> packagedb, but there's rarely a reason to do so. Usually Andrea> only the install phase needs to be done as root, while Andrea> building and configuring can be done as user. For ghc Andrea> you'd want to run ./configure and make as user and make Andrea> install as root. For normal packages, if you want to Andrea> install them system wide, you'd use something like cabal Andrea> install --global --root-cmd=sudo foo OK. I did: cabal install parsec --global --root-cmd=sudo and now when I try to make ghc I get: verify/SimplIface.lhs:16:7: Could not find module `Text.ParserCombinators.Parsec.Language': it is a member of the hidden package `parsec-2.1.0.1' Use -v to see a list of the files searched for. so I've managed to get parsec installed. Now I think I have to add it to a .cabal file somewhere. verify is a directory I added as a sub-directory of compiler, so i tried adding the following line to compiler/ghc.cabal: Build-Depends: parsec >= 2 && < 3 but it made no difference. -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Completely confused by cabal
>>>>> "Achim" == Achim Schneider writes:
Achim> Colin Paul Adams wrote:
>> So why doesn't it find packages then, when they are installed?
>>
Achim> I've got no idea, what exactly are you trying to do, and
Achim> how?
I'm trying to re-compile ghc 6.11 and it doesn't find parsec.
--
Colin Adams
Preston Lancashire
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Re: [Haskell-cafe] Re: Completely confused by cabal
So why doesn't it find packages then, when they are installed? -- Colin Adams Preston Lancashire ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
