Re: [GHC] #2953: deriving Functor, Foldable, Traversable
#2953: deriving Functor, Foldable, Traversable --+- Reporter: twanvl| Owner: twanvl Type: feature request | Status: new Priority: normal| Milestone: Component: Compiler |Version: 6.11 Severity: normal| Resolution: Keywords:| Testcase: Os: Unknown/Multiple | Architecture: Unknown/Multiple --+- Comment (by twanvl): Deriving Foldable and Traversable instances is now also possible. The code is very similar, so I abstracted it a bit. The patch is still too large to attach, it can be found at [http://twan.home.fmf.nl/files/deriving-functor3.patch.gz]. -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/2953#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
Re: [GHC] #2953: deriving Functor, Foldable, Traversable
#2953: deriving Functor, Foldable, Traversable --+- Reporter: twanvl| Owner: igloo Type: feature request | Status: new Priority: normal| Milestone: Component: Compiler |Version: 6.11 Severity: normal| Resolution: Keywords:| Testcase: Os: Unknown/Multiple | Architecture: Unknown/Multiple --+- Changes (by twanvl): * owner: twanvl = igloo -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/2953#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
Re: [GHC] #1377: GHCi debugger tasks
#1377: GHCi debugger tasks -+-- Reporter: simonmar |Owner: Type: task | Status: new Priority: normal|Milestone: 6.10 branch Component: GHCi | Version: 6.7 Severity: normal| Resolution: Keywords:| Difficulty: Unknown Testcase:| Os: Unknown/Multiple Architecture: Unknown/Multiple | -+-- Changes (by mnislaih): * cc: mnisl...@gmail.com (added) -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/1377#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
Re: Build difficulties with HEAD
Worked for me this time. Thanks! On Wed, Jan 14, 2009 at 2:29 PM, Ian Lynagh ig...@earth.li wrote: On Sun, Jan 11, 2009 at 09:42:22AM -0800, Conal Elliott wrote: Thanks, Ian. That tweak helped. Now make succeeds, but sudo make install dies, as shown below. - Conal /home/conal/downloads/ghc-6.11.20090109/utils/ghc-pkg/dist-install/build/ghc-pkg/ghc-pkg --global-conf /usr/local/lib/ghc-6.11.20090109/package.conf update - --force ghc-pkg: /usr/local/lib/ghc-6.11.20090109/package.conf: openFile: does not exist (No such file or directory) Now fixed. Thanks Ian ___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
Re: [GHC] #2962: Reduce space usage of genericLength for common Num instances
#2962: Reduce space usage of genericLength for common Num instances --+- Reporter: thorkilnaur | Owner: thorkilnaur Type: bug | Status: new Priority: normal| Milestone: Component: libraries/base|Version: 6.11 Severity: normal| Resolution: Keywords:| Testcase: Os: Unknown/Multiple | Architecture: Unknown/Multiple --+- Changes (by thorkilnaur): * owner: = thorkilnaur * summary: Fix space leak in genericLength = Reduce space usage of genericLength for common Num instances Comment: Thank you very much. I will look into this. Best regards Thorkil -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/2962#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
Questions regarding uvector 0.1.0.3
I've been looking at uvector and had some questions (hopefully this is the right mailing list for this, if not, sorry, and please direct me properly). First, is there any design thing deeper than just supporting things like the unit and pair arrays for layering UArr on top of the underlying BUArr? Second, the STG code and the native and via-C assembler generated by ghc 6.8.2 with -O2 for test :: UArr Int - Int - Int test = indexU where indexU :: UA e = UArr e - Int - e indexU arr n = indexS (streamU arr) n is a loop that simultaneously increments the offset while decrementing the index until it reaches the desired position. If I understand correctly, this indexU definition was used instead of just bring indexU from UArr into scope in order to cancel any possible unstreamU in arr, and this is a big part of the whole streamU/unstreamU magic. It replaces what would other require N^2 rules to avoid a bunch of temporaries with one. I wonder if a rule code be added to change any outstanding indexS (streamU arr) n into an UArr indexU after streamU/unstreamU fusion? Such rules for each of these type of functions (i.e., ones that aren't of the form = unstreamU . ...) would also not be N^2 and would eliminate temporary streams. Thanks! -Tyson PS: Nice code by the way. : ) signature.asc Description: This is a digitally signed message part. ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
[Haskell] How to define gunfold on List?
Hi, Does some one know how to define gunfold on recursive data struction like List? The ghc doc only give the example for non-recursive data like below. data T a b = C1 a b | C2 deriving (Typeable, Data) GHC will generate an instance that is equivalent to instance (Data a, Data b) = Data (T a b) where gfoldl k z (C1 a b) = z C1 `k` a `k` b gfoldl k z C2 = z C2 gunfold k z c = case constrIndex c of 1 - k (k (z C1)) 2 - z C2 toConstr (C1 _ _) = con_C1 toConstr C2 = con_C2 dataTypeOf _ = ty_T con_C1 = mkConstr ty_T C1 [] Prefix con_C2 = mkConstr ty_T C2 [] Prefix ty_T = mkDataType Module.T [con_C1, con_C2] ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
Re: [Haskell] How to define gunfold on List?
Hi there, There's no difference. See http://hackage.haskell.org/packages/archive/base/4.0.0.0/doc/html/src/Data-Data.html#line-1034 You can also see many other instances there. Cheers, Pedro On Sun, Jan 18, 2009 at 10:50, haihualin haihua...@163.com wrote: Hi, Does some one know how to define gunfold on recursive data struction like List? The ghc doc only give the example for non-recursive data like below. data T a b = C1 a b | C2 deriving (Typeable, Data) GHC will generate an instance that is equivalent to instance (Data a, Data b) = Data (T a b) where gfoldl k z (C1 a b) = z C1 `k` a `k` b gfoldl k z C2 = z C2 gunfold k z c = case constrIndex c of 1 - k (k (z C1)) 2 - z C2 toConstr (C1 _ _) = con_C1 toConstr C2 = con_C2 dataTypeOf _ = ty_T con_C1 = mkConstr ty_T C1 [] Prefix con_C2 = mkConstr ty_T C2 [] Prefix ty_T = mkDataType Module.T [con_C1, con_C2] ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
[Haskell] ICLP 2009: Call for workshop proposals
*** CALL FOR WORKSHOP PROPOSALS *** ICLP 2009 25th International Conference on Logic Programming Pasadena, California, USA July 14-17, 2009 URL: http://www.ist.unomaha.edu/iclp2009/ ICLP 2009, the 25th International Conference on Logic Programming, will be held in Pasadena (USA), from July 14 to 17, 2009. Workshops co-located with international conferences are one of the best venue for the presentation and discussion of preliminary work, novel ideas, and new open problems to a wide and interested audience. Co-located workshops also provide an opportunity for presenting specialized topics and opportunities for intensive discussions and project collaboration. The topics of the workshops co-located with ICLP 2009 can cover any areas related to logic programming, (e.g., theory, implementation, environments, language issues, alternative paradigms, applications),including cross-disciplinary areas. However, any workshop proposal will be considered. The format of the workshop will be decided by the workshop organizers, but ample time must be allowed for general discussion. Workshops can vary in length, but the optimal duration will be half a day or a full day. Workshop Proposal: == Those interested in organizing a workshop at ICLP 2009 are invited to submit a workshop proposal. Proposals should be in English and about two pages in length. They should contain: * The title of the workshop. * A brief technical description of the topics covered by the workshop. * A discussion of the timeliness and relevance of the workshop. * A list of some related workshops held in the last years. * The (preliminary) required number of half-days allotted to the workshop and an estimate of the number of expected attendees. * The names, affiliation, and contact details (email, web page, phone, fax) of the workshop organizer(s) together with a designated contact person. * The previous experience of the workshop organizing committee in workshop/conference organization. Proposals are expected in ASCII or PDF format. All proposals should be submitted to the Workshop Chair (Manuel Carro) by email by February 9th, 2009. Reviewing Process: == Each submitted proposal is reviewed by the Workshops Chair and the Conference Program Chairs. Proposals that appear well-organized and that fit the goals and scope of ICLP will be selected. The decision will be notified by email to the responsible organizer by February 23rd, 2009. The definitive length of the workshop will be planned according to the number of submissions received by the different workshops. For every accepted workshop, the ICLP local organizers will prepare a meeting place and arrange the distribution of the workshop proceedings, whose preparation is however in charge to the workshop organizers. The workshop registration fees will be handled together with the conference fees. Workshop Organizers' Tasks: === * Producing a Call for Papers for the workshop and posting it on the net and/or other means. Please provide a web page URL which can be linked into the ICLP 2009 home page by March 9th, 2009. * Providing a brief description of the workshop for the conference program. * Reviewing/accepting submitted papers. * Scheduling workshop activities in collaboration with the local organizers and the workshop chair. * Sending workshop program and workshop proceedings in pdf format to the workshop chair for distribution at the conference. * The use of the Computing Research Repository (CoRR) for the workshop proceedingsis strongly suggested. See http://www.logicprogramming.org/ for guidelines. We encourage reading these instructions in advance so that you can ask paper authors to prepare accordingly the final versions of their papers. Location: = All workshops will take place in Pasadena at the site of the main conference. See the ICLP 2009 web site for location details. Important Dates: February 9, 2009: Proposal submission deadline. February 23, 2009: Notification. March 9, 2009: Deadline to receive the CFP and URL for the web page of the workshop June 1, 2009: Deadline for preliminary proceedings. July 14-17, 2009: ICLP 2009 workshops. Workshop Chair: === Manuel Carro [mcarro AT fi dot upm dot es] (www.clip.dia.fi.upm.es/~mcarro) ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
[Haskell] ANNOUNCE: Turbinado V0.4
Turbinado (http://www.turbinado.com) is an easy to use Model-View-Controller-ish web framework for Haskell. The source for the framework can be found at: http://github.com/alsonkemp/turbinado The source for the website turbinado.org can be found at: http://github.com/alsonkemp/turbinado-website (see the /App directory for the code for www.turbinado.org) Release 0.4 contains: * A dramatically improved ORM (or Type-Relation Mapper) which handles foreign keys. Still PostgreSQL only at this point. * All dependencies in tmp/dependencies to ease building the application. * In code documentation (not complete, but starting). * Documentation (see http://turbinado.org/Architecture). Release 0.5 will focus on: * Ease of installation! * Moving to GHC 6.10 (whenever Debian shifts). Diego Eche provided a port from plugins to ghc-api. * Additional functionality (e.g. sessions, authentication, etc). * Tutorials. ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
Re: [Haskell] ANNOUNCE: Turbinado V0.4
-- From: Alson Kemp al...@alsonkemp.com Sent: Sunday, January 18, 2009 6:06 PM To: haskell@haskell.org Subject: [Haskell] ANNOUNCE: Turbinado V0.4 Turbinado (http://www.turbinado.com) is an easy to use Model-View-Controller-ish web framework for Haskell. You mean http://www.turbinado.org ? :-) ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
[Haskell] Re: ANNOUNCE: Turbinado V0.4
Turbinado (http://www.turbinado.com) is an easy to use Oops. That should be !! http://www.turbinado.org. !! - Alson ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
[Haskell] Re: HaskellWiki Update
On Sat, 17 Jan 2009 20:47:39 -0800, Ashley Yakeley ash...@semantic.org wrote: There has been a lot of spam on HaskellWiki. Since anonymous edits have been switched off, a spammer tactic has been to create hundreds of accounts to evade individual account blocks. To combat this, I have 1. deleted all user accounts that have made no edits; 2. switched off account creation; 3. blocked at least some of the remaining spam accounts. This is obviously not ideal, as there is now no way for new users to edit the wiki. I will investigate appropriate ways to allow account creation. Instead of switching off all new account creation, perhaps you could shut off account creation/access for just those domains for which spammers have been creating accounts? -- Benjamin L. Russell -- Benjamin L. Russell / DekuDekuplex at Yahoo dot com http://dekudekuplex.wordpress.com/ Translator/Interpreter / Mobile: +011 81 80-3603-6725 Furuike ya, kawazu tobikomu mizu no oto. -- Matsuo Basho^ ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
[Haskell] ANN: curl-1.3.4
Hi, a new version 'curl', a complete Haskell binding to the libcurl API, is now available and have been uploaded to Hackage: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/curl Git repo at git://code.galois.com/curl.git Appended is the list of changes since the previous release. Most notable is the overloading of representation of response buffers (and headers), allowing for the use of ByteStrings. Speedups might be had as a result... enjoy --sigbjorn Version 1.3.4: released 2009-01-18; changes from 1.3.3 * Overloaded Network.Curl operations over response representation of payloads and headers. Controlled via CurlBuffer and CurlHeader classes. New actions: - curlGetString_, curlGetResponse_, perform_with_response_, do_curl_, curlHead_ * Provided ByteString instances (strict and lazy) * No modification in calling interface to existing exports, so backwards compatible. * Added Show instance for Network.Curl.Opts.CurlOption * curl_version_string, curl_version_number now gives you access to version info of underlying lib you _compiled_ the package with. * Sync'ed wrt libcurl-7.19.2, so bunch of new options added to Network.Curl.Opts. Use version functions to determine if they are supported though. ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
Re: [Haskell-cafe] Comments from OCaml Hacker Brian Hurt
On Sun, 18 Jan 2009 08:51:10 +0100 david48 dav.vire+hask...@gmail.com wrote: On Sat, Jan 17, 2009 at 11:19 PM, Dan Piponi dpip...@gmail.com wrote: On Sat, Jan 17, 2009 at 1:47 AM, david48 dav.vire+hask...@gmail.com wrote: why would I need to write a running count this way instead of, for example, a non monadic fold, which would probably result in clearer and faster code? Maybe my post here will answer some questions like that: http://sigfpe.blogspot.com/2009/01/haskell-monoids-and-their-uses.html Just wow. Very very nice post. one to keep in the wikis. Thank you *very* much, Dan, for writing this. Seconded. And I hope, Dan, that you will find time at some point to write about those other things you said at the end that you didn't have time to write about! -- Robin ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Functors [Comments from OCaml Hacker Brian Hurt]
Andrew Coppin wrote: instance (Monad m) = Functor m where fmap f ma = do a - ma; return (f a) While that's quite interesting from a mathematical point of view, how is this useful for programming purposes? Surely, you agree that liftM is useful? Because that's the same thing. Regards, apfelmus -- http://apfelmus.nfshost.com ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Comments from OCaml Hacker Brian Hurt
John Lato wrote: Here is the current complete documentation for Data.Monoid 'mappend', which happens to be a good example of which I speak: An associative operation That could mean anything. There are lots of associative operations. Yes. In combination with the definition of mempty (the identity for mappend) that's exactly what a monoid is. I'm not (just) being flippant. This particular example actually highlights the limitations of type classes. There are, in fact, too many monoids. Too many to be able to define it based only on the carrier, i.e. the type that mempty belongs to and that mappend operates over. For example every (semi-)ring has at least two of them[1]. For more complicated mathematical structures there can be even more than that. This isn't to say that we should get rid of Monoid, just that using it can be... troublesome. But this has been mentioned already on a few other recent threads. The notion of appending only really applies to the free monoid on a set A, aka strings of elements drawn from A. It bears highlighting that I said strings (in the mathematical sense) and not (linked) lists. The concatenation involved is mathematical juxtaposition, and the empty element is the empty string (which is subtly different than the empty list which is also used to terminate the datatype's recursion). These monoids are called free because they make no requirements on the underlying set, no requirements other than the monoid laws. All other monoids use some sort of structure in the underlying set in order to simplify expressions (e.g. 1+1 == 2, whereas a+a == aa). Because the free monoid doesn't simplify anything, all it does is append. [1] For example, Natural numbers: (Nat,+,0) (Nat,*,1) Boolean algebra: (Bool,or,False) (Bool,and,True) Bit-vector algebra: (Bits,bitOr,0) (Bits,bitAnd,-1) Any lattice L: (L,join,Bottom) (L,meet,Top) Any total ordering O: (O,max,NegativeInfinity) (O,min,Infinity) Any set universe U: (Power(U),union,EmptySet) (Power(U),intersection,U) ...let alone getting into fun things like the log-semiring, polynomials with natural coefficients, and so on. -- Live well, ~wren ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Comments from OCaml Hacker Brian Hurt
Paul Moore wrote: Apfelmus, Heinrich wrote: How to learn? The options are, in order of decreasing effectiveness university course teacher in person book irc mailing list online tutorial haskell wiki haddock documentation Reason by analogy from known/similar areas. I think the point here is that for Haskell, this is more possible for mathematicians than for programmers. And that's an imbalance that may need to be addressed (depending on who you want to encourage to learn). But I agree that reasoning by analogy is not a very good way of learning. And I think it's been established that the real issue here is the documentation - complete explanations and better discoverability[1] are needed. Yes, agreed. However, I would say that the word documentation does not apply anymore, it's more subject of study. What I want to say is that to some extend, Haskell is not only similar to mathematics, it /is/ mathematics, so programmers have to learn mathematics. Traditionally, this is done in university courses or with books, I'm not sure whether learning mathematics via internet tutorials on the computer screen works. Regards, apfelmus -- http://apfelmus.nfshost.com ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Slow Text.JSON parser
On Sun, Jan 18, 2009 at 6:07 AM, Sigbjorn Finne sigbjorn.fi...@gmail.com wrote: Maybe. Handling the common cases reasonably well is probably worth doing first (+profiling) before opting for a heartlung transplant.. To wit, I've trivially improved the handling of string and integer lits in version 0.4.3 (just released.) It cuts down the running times by a factor of 2-3 on larger inputs -- Indeed, I have just tried version 0.4.3 and my previous test which took about 3 seconds to run is now running in about one second. Very nice improvement. Thanks for all your work Sigbjorn. Cheers, Levi ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Functors [Comments from OCaml Hacker Brian Hurt]
Heinrich Apfelmus wrote: Andrew Coppin wrote: instance (Monad m) = Functor m where fmap f ma = do a - ma; return (f a) While that's quite interesting from a mathematical point of view, how is this useful for programming purposes? Surely, you agree that liftM is useful? Because that's the same thing. Then why not just use liftM? (That way, you know what it does...) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Functors [Comments from OCaml Hacker Brian Hurt]
Andrew Coppin wrote: Heinrich Apfelmus wrote: Andrew Coppin wrote: instance (Monad m) = Functor m where fmap f ma = do a - ma; return (f a) While that's quite interesting from a mathematical point of view, how is this useful for programming purposes? Surely, you agree that liftM is useful? Because that's the same thing. Then why not just use liftM? (That way, you know what it does...) liftM (*1) [1..10] = [2,4,6,8,10,12,14,16,18,20] Regards, apfelmus -- http://apfelmus.nfshost.com ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Comments from OCaml Hacker Brian Hurt
Ertugrul Soeylemez wrote: Andrew Coppin andrewcop...@btinternet.com wrote: I would suggest that ExistentiallyQuantifiedTypeVariables would be an improvement [...] That must be a joke. Typing the long extension names in LANGUAGE pragmas over and over again is tiring and annoying enough already. We really don't need even longer names, and your improvement fills up almost half of the width of an 80 characters terminal. Which is why I personally prefer HiddenTypeVariables. (This has the advantage of using only pronouncible English words, which means you can use it when speaking out loud.) But, as I say, nobody is going to rename anything, so it's moot. I can't await the next Haskell standard, where at last all those extensions are builtin. This frightens me. At the moment, I understand how Haskell 98 works. There are lots of extensions out there, but I don't have to care about that because I don't use them. If I read somebody else's code and it contains a LANGUAGE pragma, I can immediately tell that the code won't be comprehendable, so I don't need to waste time trying to read it. But once Haskell' becomes standard, none of this holds any more. Haskell' code will use obscure lanuage features without warning, and unless I somehow learn every extension in the set, I'll never be able to read Haskell again! (One presumes that they won't add any extensions which actually *break* backwards compatibility, so hopefully I can still pretend these troublesome extensions don't exist when writing my own code...) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Functors [Comments from OCaml Hacker Brian Hurt]
Jonathan Cast wrote: On Sat, 2009-01-17 at 12:04 +, Andrew Coppin wrote: instance (Monad m) = Functor m where fmap f ma = do a - ma; return (f a) While that's quite interesting from a mathematical point of view, how is this useful for programming purposes? Good Lord. fmap (as above) is *at least* useful enough to be in the standard library! (Control.Monad.liftM). Given that liftM exists, why is having an identical implementation for fmap useful? The example that leaps out at me is that (=) is identical to concatMap within the list monad. But using lists as a monad is a generally useful thing to do, and being able to substitute arbitrary monads has obvious utility. I'm not seeing how being able to treat something that isn't a container as if it was a container is useful. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Functors [Comments from OCaml Hacker Brian Hurt]
On Sun, Jan 18, 2009 at 3:23 AM, Andrew Coppin andrewcop...@btinternet.com wrote: Given that liftM exists, why is having an identical implementation for fmap useful? For many structures, it's easier to define (=) in terms of fmap and join. For these objects, often the generic implementation of liftM is far less efficient than fmap. That is to say, given a monad T and these functions: returnT :: a - T a fmapT :: (a - b) - T a - T b joinT :: T (T a) - T a We can create Haskell instances as follows instance Functor T where fmap = fmapT instance Monad T where return = returnT m = f = joinT (fmap f m) Then, liftM f m = m = \x - return (f x) = joinT (fmapT (\x - return (f x)) m) Now, we know (by the monad functor laws) that this is equivalent to (fmap f m), but it's a lot harder for the compiler to spot that. The list monad is a great example; I'd expect that using fmap (== map) in the list monad is significantly more efficient than liftM which constructs a singleton list for each element of the input and concatenates them all together. -- ryan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Optimistic evaluation
Hi folks. I just read a rather interesting paper about a fork of GHC that performs optimistic evaluation. This shows big wins in some cases. The authors claim to have implemented this in a fork of GHC and promised that it would be integrated into the production compiler in the near future. Curios, I investigated the GHC wiki... Well, let's see now. The front page has links to out release plans for 6.8.3 and what will be in 6.10. The latter page, http://hackage.haskell.org/trac/ghc/wiki/Status/Releases mentions that a beta has just been released... and seems oblivious to the fact that 6.10.1 is production now. Clearly, any hopes I might have had of getting a handle on the current status of GHC from this wiki were dashed somewhat. ;-) Does anybody have any suggestions for a more reliable way of figuring out what the current activities and plans for GHC are? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Comments from OCaml Hacker Brian Hurt
On Sat, Jan 17, 2009 at 09:12:32PM -0500, a...@spamcop.net wrote: And FWIW, I agree with everyone who has commented that the documentation is inadequate. It'd be nice if there was some way to contribute better documentation without needing checkin access to the libraries. There is. The current state of the docs may be viewed at http://www.haskell.org/ghc/dist/current/docs/libraries/ Anyone can check out the darcs repos for the libraries, and post suggested improvements to the documentation to librar...@haskell.org (though you have to subscribe). It doesn't even have to be a patch. Sure, it could be smoother, but there's hardly a flood of contributions. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: Re[2]: [Haskell-cafe] Comments from OCaml Hacker Brian Hurt
On Sat, 2009-01-17 at 13:36 -0800, David Leimbach wrote: On Sat, Jan 17, 2009 at 9:16 AM, david48 dav.vire+hask...@gmail.com wrote: On Sat, Jan 17, 2009 at 4:08 PM, David Leimbach leim...@gmail.com wrote: So you're saying it should be better documented in Haskell what a Monoid is. Did you say you searched for C++ class why not Haskell Monoid then? The first correct google hit that didn't think I meant Monads, takes you straight to the GHC documentation for Data.Monoid. Read my first post on the thread, that's exactly what I did ( and then complained that the doc for Data.Monoid was close to useless ) Sorry missed it! This is an exceptionally long thread! :-) I agree Data.Monoid's docs don't give you much to work with. Do you think they look better now: http://www.haskell.org/ghc/dist/current/docs/libraries/base/Data-Monoid.html Any other improvements you'd make? Duncan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] real haskell difficulties (at least for me)
Interesting and thoughtful, thanks. I think we need to file these ideas in the hackage trac. They've been floating about for a while but we need to get them properly recorded. On Sun, 2009-01-18 at 01:06 -0500, wren ng thornton wrote: Minimally these aggregated reports should indicate the package and version, the problem, the Haskell compiler and its version, as well as the OS. Since some packages have many dependencies or make heavy use of the FFI, CPP, or have architecture dependent differences, it would be nice to be able to set per-package preferences to get additional information like OS version, dependency versions, CPU info, build logs, etc. The information we would collect for anonymous reports would be just: package: HTTP-4000.0.2 os: linux arch: x86_64 compiler: ghc-6.10.1 client: cabal-install-0.6.1 flags: -old-base dependencies: array-0.2.0.0 base-3.0.3.0 bytestring-0.9.1.5 mtl-1.1.0.2 network-2.2.0.1 parsec-2.1.0.1 install-outcome: InstallOk docs-outcome: NotTried tests-outcome: NotTried This is all machine readable of course so we can aggregate information from 1000s of reports. Since it can be hard to set up sandboxes for every configuration, it'd also be nice if clients could opt in to send contact email as well, if they're willing to back-and-forth with the developer to fix things in the event of bugs. Non-anonymous reports with build logs will have to be associated with registered accounts. I expect that would provide a way to get in touch with some testers. Some of the testers of course will just be automated build clients. Second, and this would take more work, I would like it if the Haddock documentation for packages could be given a wiki-like and/or reddit-like interface so that people could make comments about what is unclear or needs better documentation as well as offering spelling/grammar/punctuation suggestions[2]. Viewers should be able to set preferences for whether they want to see the real/current documentation, or whether they want to see the commented/modified version (hiding things below a certain depth or rank for reddit-like). We had a thread on this the other day with similar ideas. Duncan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: Re[2]: [Haskell-cafe] ANN: HTTPbis / HTTP-4000.x package available
On Sat, 2009-01-17 at 20:34 -1000, Tim Newsham wrote: Speaking of proxies, I've been looking into how to find the right proxy to use on Windows systems. Turns out that to do it properly you need a JavaScript interpreter! Yes, really. Uhh.. What!? That's not right. I think you mean it should not be right! :-) Of course it's possible to specify a list of proxies in Windows and that info is kept in the registry. It's also common in corporate networks to use proxy auto-configuration. The client gets told the URL of the these (.pac) files and the client downloads it to work out what proxy to use. You'll notice a space to specify an auto-configuration URL (.pac file) in the proxy setting dialog of any web browser. Proxy auto-configuration files are JavaScript. It uses more or less the full JavaScript language (ECMA these days), though with a small subset of the standard library. Web browsers are ok because they've got a JavaScript interpreter. The MS WinHTTP library uses the Windows scripting host service. The open source pacparser C library links to the Mozilla SpiderMonkey JavaScript engine. Apparently we have Netscape to thank for this mess. Duncan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Comments from OCaml Hacker Brian Hurt
Andrew Coppin wrote: I can't await the next Haskell standard, where at last all those extensions are builtin. This frightens me. The example he had had the uses keyword, so I assume it's built in in the same way Perl pragma are built in. So you can happily ignore code when you see uses at the top of the file. ;) Although I could be wrong. Cheers, Cory ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ANNOUNCE: Coadjute 0.0.1, generic build tool
Matti Niemenmaa schrieb: Announcing the release of Coadjute, version 0.0.1! Web site: http://iki.fi/matti.niemenmaa/coadjute/ Hackage: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Coadjute Coadjute is a generic build tool, intended as an easier to use and more portable replacement for make. It’s not tailored toward any particular language, and is not meant to replace tools which target a specific environment (such as ghc --make or Cabal, taking Haskell as an example). I've been sitting on this for a couple of months now and figured I might as well push it out since it seems to be in relative working order. I've used it on my web site since July and it hasn't resulted in data loss yet. How does it compare to http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hake ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Comments from OCaml Hacker Brian Hurt
- Original Message From: Andrew Coppin andrewcop...@btinternet.com Which is why I personally prefer HiddenTypeVariables. (This has the advantage of using only pronouncible English words, which means you can use it when speaking out loud.) Existential - English, easy to pronounce Quantify - English, easy to pronounce I know I've been seeing those backwards E's and upside down A's in not-so-advanced Maths courses for a long time (since high school, I'm sure) and I certainly encountered them before 'Boolean'. If you could do a geometry proof in high school, you have the Maths background need to understand the ideas. (How they apply to types is another story, but the words shouldn't be scary.) I can't await the next Haskell standard, where at last all those extensions are builtin. This frightens me. At the moment, I understand how Haskell 98 works. There are lots of extensions out there, but I don't have to care about that because I don't use them. If I read somebody else's code and it contains a LANGUAGE pragma, I can immediately tell that the code won't be comprehendable, so I don't need to waste time trying to read it. But once Haskell' becomes standard, none of this holds any more. Haskell' code will use obscure lanuage features without warning, and unless I somehow learn every extension in the set, I'll never be able to read Haskell again! (One presumes that they won't add any extensions which actually *break* backwards compatibility, so hopefully I can still pretend these troublesome extensions don't exist when writing my own code...) Some of the most useful libraries (e.g. parsec, generics) use these type system extensions (higher rank polymorphism, existentials). It would be great if these could be considered 'standard Haskell'. ___ 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] Re: ANN: leapseconds-announced-2009
On Sun, Jan 18, 2009 at 00:37, Ashley Yakeley ash...@semantic.org wrote: On Sun, 2009-01-18 at 00:34 -0500, Bjorn Buckwalter wrote: Thanks for the pointer. My source is the Earth Orientation Parameter (EOP) data at http://www.celestrak.com/SpaceData/; specifically I autogenerate the module from http://www.celestrak.com/SpaceData/eop19620101.txt. Probably looks more complicated than necessary but I'm parsing the file anyway for other purposes. With tz, though, you could discover the table at run-time and so be more likely to be up to date. Ah yes. However, just like time this library does not attempt to solve that particular problem. The purpose of leapseconds-announced is to be dead easy to use (no IO and treading of the LeapSecondTable to the usage point), at the cost of longevity. Of course, as I pointed out in the announcement this trade-off isn't suitable for all applications. -Bjorn ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Comments from OCaml Hacker Brian Hurt
Andrew Coppin andrewcop...@btinternet.com wrote: Ertugrul Soeylemez wrote: Andrew Coppin andrewcop...@btinternet.com wrote: I would suggest that ExistentiallyQuantifiedTypeVariables would be an improvement [...] That must be a joke. Typing the long extension names in LANGUAGE pragmas over and over again is tiring and annoying enough already. We really don't need even longer names, and your improvement fills up almost half of the width of an 80 characters terminal. Which is why I personally prefer HiddenTypeVariables. (This has the advantage of using only pronouncible English words, which means you can use it when speaking out loud.) But, as I say, nobody is going to rename anything, so it's moot. Well, yes, unfortunately, unless someone proposes extension renamings together with a long paper about the psychological implications and advantages of using shorter names. I can't await the next Haskell standard, where at last all those extensions are builtin. This frightens me. At the moment, I understand how Haskell 98 works. There are lots of extensions out there, but I don't have to care about that because I don't use them. If I read somebody else's code and it contains a LANGUAGE pragma, I can immediately tell that the code won't be comprehendable, so I don't need to waste time trying to read it. But once Haskell' becomes standard, none of this holds any more. Haskell' code will use obscure lanuage features without warning, and unless I somehow learn every extension in the set, I'll never be able to read Haskell again! (One presumes that they won't add any extensions which actually *break* backwards compatibility, so hopefully I can still pretend these troublesome extensions don't exist when writing my own code...) I think, the list of accepted extensions is well chosen. And don't worry, the extensions I'm talking about mainly, are easy to comprehend and very useful, for example multi-parameter type classes and rank-n types. Greets, Ertugrul. -- nightmare = unsafePerformIO (getWrongWife = sex) http://blog.ertes.de/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] runghc Setup.hs doitall
Is there some sort of bundle that you can use to install cabal-install easily? Because it looks to me like I'd have to spend the better part of an evening manually downloading and installing the gazillion of dependencies it has, which is far too much work when I just wanted to spend ten minutes playing with some package... -- From: Daniel Fischer daniel.is.fisc...@web.de Sent: Saturday, January 17, 2009 10:35 PM To: Alberto G. Corona agocor...@gmail.com; haskell-cafe@haskell.org Subject: Re: [Haskell-cafe] runghc Setup.hs doitall Am Samstag, 17. Januar 2009 23:20 schrieb Alberto G. Corona: Hi guys: I don´t know how difficult really is, but it seens that it could be done because all the necessary elements are there (except perhaps the mapping package name-hackage url): Why hasn´t been done yet Is unknown to me. It would be very useful and a big save of time to have a cabal commad chech-dependencies-and-install-them-by-downloading-them-from-hackage-then- configure-build-and-install-this-package?. The unix installers do is t from binaries and are obsolete, so I have to do it manually with cabal everytime when i download a new compiler version from haskell.org. Cheers Alberto. Use cabal-install: cabal update cabal install foo checks for dependencies, downloads and builds them automatically (if possible). ___ 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] runghc Setup.hs doitall
On Sun, 2009-01-18 at 16:22 +, Sebastian Sylvan wrote: Is there some sort of bundle that you can use to install cabal-install easily? Because it looks to me like I'd have to spend the better part of an evening manually downloading and installing the gazillion of dependencies it has, which is far too much work when I just wanted to spend ten minutes playing with some package... There's a bootstrap.sh file in root of the cabal-install that can do this automatically. In my experience, it usually fails because of missing dependencies like zlib-dev on my own system, but those are easy to fix, at which point I can rerun the bootstrap script. Jeff Wheeler ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] runghc Setup.hs doitall
2009/1/18 Sebastian Sylvan sebastian.syl...@gmail.com: Is there some sort of bundle that you can use to install cabal-install easily? Newer versions contain a bootstrap.sh script that works just fine for me. Cheers, Peter ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] runghc Setup.hs doitall
Doesn't work on windows. -- From: Jeff Wheeler j...@nokrev.com Sent: Sunday, January 18, 2009 4:27 PM To: haskell-cafe@haskell.org Subject: Re: [Haskell-cafe] runghc Setup.hs doitall On Sun, 2009-01-18 at 16:22 +, Sebastian Sylvan wrote: Is there some sort of bundle that you can use to install cabal-install easily? Because it looks to me like I'd have to spend the better part of an evening manually downloading and installing the gazillion of dependencies it has, which is far too much work when I just wanted to spend ten minutes playing with some package... There's a bootstrap.sh file in root of the cabal-install that can do this automatically. In my experience, it usually fails because of missing dependencies like zlib-dev on my own system, but those are easy to fix, at which point I can rerun the bootstrap script. Jeff Wheeler ___ 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
Improved documentation for Bool (Was: [Haskell-cafe] Comments from OCaml Hacker Brian Hurt)
On Sun, 18 Jan 2009, Ross Paterson wrote: Anyone can check out the darcs repos for the libraries, and post suggested improvements to the documentation to librar...@haskell.org (though you have to subscribe). It doesn't even have to be a patch. Sure, it could be smoother, but there's hardly a flood of contributions. I noticed the Bool datatype isn't well documented. Since Bool is not a common English word, I figured it could use some haddock to help clarify it for newcomers. -- |The Bool datatype is named after George Boole (1815-1864). -- The Bool type is the coproduct of the terminal object with itself. -- As a coproduct, it comes with two maps i : 1 - 1+1 and j : 1 - 1+1 -- such that for any Y and maps u: 1 - Y and v: 1 - Y, there is a unique -- map (u+v): 1+1 - Y such that (u+v) . i = u, and (u+v) . j = v -- as shown in the diagram below. -- -- 1 -- u -- Y -- ^ ^^ -- |/ | -- i u + v v -- | /| -- 1+1 - j -- 1 -- -- In Haskell we call we define 'False' to be i(*) and 'True' to be j(*) -- where *:1. -- Furthermore, if Y is any type, and we are given a:Y and b:Y, then we -- can define u(*) = a and v(*) = b. -- From the above there is a unique map (u + v) : 1+1 - Y, -- or in other words, (u+v) : Bool - Y. -- Haskell has a built in syntax for this map: -- @if z then a else b@ equals (u+v)(z). -- -- From the commuting triangle in the diagram we see that -- (u+v)(i(*)) = u(*). -- Translated into Haskell notation, this law reads -- @if True then a else b = a...@. -- Similarly from the other commuting triangle we see that -- (u+v)(j(*)) = v(*), which means -- @if False then a else b = b@ -- Russell O'Connor http://r6.ca/ ``All talk about `theft,''' the general counsel of the American Graphophone Company wrote, ``is the merest claptrap, for there exists no property in ideas musical, literary or artistic, except as defined by statute.'' ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] runghc Setup.hs doitall
Am Sonntag, 18. Januar 2009 17:22 schrieb Sebastian Sylvan: Is there some sort of bundle that you can use to install cabal-install easily? Because it looks to me like I'd have to spend the better part of an evening manually downloading and installing the gazillion of dependencies it has, which is far too much work when I just wanted to spend ten minutes playing with some package... Wait, 'gazillion of dependencies'? If you have the extralibs bundle built, there are only three dependencies to take care of - a recent Cabal library - HTTP - zlib Of course, downloading and building them manually may take half an hour or so, but it's time well spent, cabal-install makes playing around for ten minutes with some other package so much easier. And of course, as has already been mentioned, there's now a bootstrap.sh included which takes care of the above dependencies for you. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: Improved documentation for Bool (Was: [Haskell-cafe] Comments from OCaml Hacker Brian Hurt)
rocon...@theorem.ca wrote: On Sun, 18 Jan 2009, Ross Paterson wrote: Anyone can check out the darcs repos for the libraries, and post suggested improvements to the documentation to librar...@haskell.org (though you have to subscribe). It doesn't even have to be a patch. Sure, it could be smoother, but there's hardly a flood of contributions. I noticed the Bool datatype isn't well documented. Since Bool is not a common English word, I figured it could use some haddock to help clarify it for newcomers. -- |The Bool datatype is named after George Boole (1815-1864). -- The Bool type is the coproduct of the terminal object with itself. -- As a coproduct, it comes with two maps i : 1 - 1+1 and j : 1 - 1+1 -- such that for any Y and maps u: 1 - Y and v: 1 - Y, there is a unique -- map (u+v): 1+1 - Y such that (u+v) . i = u, and (u+v) . j = v -- as shown in the diagram below. -- -- 1 -- u -- Y -- ^ ^^ -- |/ | -- i u + v v -- | /| -- 1+1 - j -- 1 -- -- In Haskell we call we define 'False' to be i(*) and 'True' to be j(*) -- where *:1. -- Furthermore, if Y is any type, and we are given a:Y and b:Y, then we -- can define u(*) = a and v(*) = b. -- From the above there is a unique map (u + v) : 1+1 - Y, -- or in other words, (u+v) : Bool - Y. -- Haskell has a built in syntax for this map: -- @if z then a else b@ equals (u+v)(z). -- -- From the commuting triangle in the diagram we see that -- (u+v)(i(*)) = u(*). -- Translated into Haskell notation, this law reads -- @if True then a else b = a...@. -- Similarly from the other commuting triangle we see that -- (u+v)(j(*)) = v(*), which means -- @if False then a else b = b@ I'm going to go ahead and assume this was a joke and crack up... The sad part is I didn't actually find this difficult to read... Cory lost touch with the real world Knapp ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: Improved documentation for Bool (Was: [Haskell-cafe] Comments from OCaml Hacker Brian Hurt)
Am Sonntag, 18. Januar 2009 17:48 schrieb rocon...@theorem.ca: On Sun, 18 Jan 2009, Ross Paterson wrote: Anyone can check out the darcs repos for the libraries, and post suggested improvements to the documentation to librar...@haskell.org (though you have to subscribe). It doesn't even have to be a patch. Sure, it could be smoother, but there's hardly a flood of contributions. I noticed the Bool datatype isn't well documented. Since Bool is not a common English word, I figured it could use some haddock to help clarify it for newcomers. Thanks. Really helpful. A few minor typos, though. -- |The Bool datatype is named after George Boole (1815-1864). -- The Bool type is the coproduct of the terminal object with itself. -- As a coproduct, it comes with two maps i : 1 - 1+1 and j : 1 - 1+1 -- such that for any Y and maps u: 1 - Y and v: 1 - Y, there is a unique -- map (u+v): 1+1 - Y such that (u+v) . i = u, and (u+v) . j = v -- as shown in the diagram below. -- -- 1 -- u -- Y -- ^ ^^ -- |/ | -- i u + v v -- | /| -- 1+1 - j -- 1 You have the arrows i and j pointing in the wrong direction. -- -- In Haskell we call we define 'False' to be i(*) and 'True' to be j(*) Delete we call. -- where *:1. -- Furthermore, if Y is any type, and we are given a:Y and b:Y, then we -- can define u(*) = a and v(*) = b. -- From the above there is a unique map (u + v) : 1+1 - Y, -- or in other words, (u+v) : Bool - Y. -- Haskell has a built in syntax for this map: -- @if z then a else b@ equals (u+v)(z). -- -- From the commuting triangle in the diagram we see that -- (u+v)(i(*)) = u(*). -- Translated into Haskell notation, this law reads -- @if True then a else b = a...@. -- Similarly from the other commuting triangle we see that -- (u+v)(j(*)) = v(*), which means -- @if False then a else b = b@ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] runghc Setup.hs doitall
On Sun, Jan 18, 2009 at 8:22 AM, Sebastian Sylvan sebastian.syl...@gmail.com wrote: Is there some sort of bundle that you can use to install cabal-install easily? Because it looks to me like I'd have to spend the better part of an evening manually downloading and installing the gazillion of dependencies it has, which is far too much work when I just wanted to spend ten minutes playing with some package... You typically need HTTP and zlib. Perhaps cabal-install could have it's own minimal implementations to be standalone? However I don't find needing to cabal build and install 2 packages to be so difficult. And once you have cabal-install, you've got it ;-) It should be able to update itself. Maybe adding cabal-install to the ghc packaging solves all the problems, then they just need zlib and http in the main distribution. Dave -- From: Daniel Fischer daniel.is.fisc...@web.de Sent: Saturday, January 17, 2009 10:35 PM To: Alberto G. Corona agocor...@gmail.com; haskell-cafe@haskell.org Subject: Re: [Haskell-cafe] runghc Setup.hs doitall Am Samstag, 17. Januar 2009 23:20 schrieb Alberto G. Corona: Hi guys: I don´t know how difficult really is, but it seens that it could be done because all the necessary elements are there (except perhaps the mapping package name-hackage url): Why hasn´t been done yet Is unknown to me. It would be very useful and a big save of time to have a cabal commad chech-dependencies-and-install-them-by-downloading-them-from-hackage-then- configure-build-and-install-this-package?. The unix installers do is t from binaries and are obsolete, so I have to do it manually with cabal everytime when i download a new compiler version from haskell.org. Cheers Alberto. Use cabal-install: cabal update cabal install foo checks for dependencies, downloads and builds them automatically (if possible). ___ 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 mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: Improved documentation for Bool (Was: [Haskell-cafe] Comments from OCaml Hacker Brian Hurt)
2009/1/18 Daniel Fischer daniel.is.fisc...@web.de: Am Sonntag, 18. Januar 2009 17:48 schrieb rocon...@theorem.ca: On Sun, 18 Jan 2009, Ross Paterson wrote: Anyone can check out the darcs repos for the libraries, and post suggested improvements to the documentation to librar...@haskell.org (though you have to subscribe). It doesn't even have to be a patch. Sure, it could be smoother, but there's hardly a flood of contributions. I noticed the Bool datatype isn't well documented. Since Bool is not a common English word, I figured it could use some haddock to help clarify it for newcomers. Thanks. Really helpful. A few minor typos, though. -- |The Bool datatype is named after George Boole (1815-1864). -- The Bool type is the coproduct of the terminal object with itself. -- As a coproduct, it comes with two maps i : 1 - 1+1 and j : 1 - 1+1 -- such that for any Y and maps u: 1 - Y and v: 1 - Y, there is a unique -- map (u+v): 1+1 - Y such that (u+v) . i = u, and (u+v) . j = v -- as shown in the diagram below. -- -- 1 -- u -- Y -- ^ ^^ -- |/ | -- i u + v v -- | /| -- 1+1 - j -- 1 You have the arrows i and j pointing in the wrong direction. -- -- In Haskell we call we define 'False' to be i(*) and 'True' to be j(*) Delete we call. -- where *:1. -- Furthermore, if Y is any type, and we are given a:Y and b:Y, then we -- can define u(*) = a and v(*) = b. -- From the above there is a unique map (u + v) : 1+1 - Y, -- or in other words, (u+v) : Bool - Y. -- Haskell has a built in syntax for this map: -- @if z then a else b@ equals (u+v)(z). Also, equals (a+b)(z) should be here. -- -- From the commuting triangle in the diagram we see that -- (u+v)(i(*)) = u(*). -- Translated into Haskell notation, this law reads -- @if True then a else b = a...@. -- Similarly from the other commuting triangle we see that -- (u+v)(j(*)) = v(*), which means -- @if False then a else b = b@ ___ 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: Improved documentation for Bool (Was: [Haskell-cafe] Comments from OCaml Hacker Brian Hurt)
On Sun, Jan 18, 2009 at 5:48 PM, rocon...@theorem.ca wrote:
I noticed the Bool datatype isn't well documented. Since Bool is not a
common English word, I figured it could use some haddock to help clarify it
for newcomers.
-- |The Bool datatype is named after George Boole (1815-1864).
-- The Bool type is the coproduct of the terminal object with itself.
Russell, this does seem like it might be very helpful, but it might be
useful to include a note about what category you are working in.
People may sometimes naively assume that one is working in the
category of Haskell/Hugs/GHC data types and Haskell functions, in
which there are no terminal -- or initial -- objects ('undefined' and
'const undefined' are distinct maps between any two objects X and Y),
or else in the similar category without lifted bottoms, in which the
empty type is terminal and the unit type isn't ('undefined' and 'const
()' are both maps from any object X to the unit type). These niceties
will not confuse the advanced reader, but it may help the beginner if
you are more explicit.
- Benja
P.S. :-)
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Re: [Haskell-cafe] Functors [Comments from OCaml Hacker Brian Hurt]
On Sun, Jan 18, 2009 at 3:23 AM, Andrew Coppin andrewcop...@btinternet.comwrote: Jonathan Cast wrote: On Sat, 2009-01-17 at 12:04 +, Andrew Coppin wrote: instance (Monad m) = Functor m where fmap f ma = do a - ma; return (f a) While that's quite interesting from a mathematical point of view, how is this useful for programming purposes? Good Lord. fmap (as above) is *at least* useful enough to be in the standard library! (Control.Monad.liftM). Given that liftM exists, why is having an identical implementation for fmap useful? Because liftM works on Monads and fmap works on Functors? I believe you can make data that are Functors but are not Monads. The example that leaps out at me is that (=) is identical to concatMap within the list monad. But using lists as a monad is a generally useful thing to do, and being able to substitute arbitrary monads has obvious utility. I'm not seeing how being able to treat something that isn't a container as if it was a container is useful. ___ 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: Improved documentation for Bool (Was: [Haskell-cafe] Comments from OCaml Hacker Brian Hurt)
This is a great effort, but the root of the problem isn't just poor
documentation, but an insistence on some obscure name. How about
renaming Bool to YesOrNoDataVariable? I think this would help novice
programmers a great deal.
It would also make the documentation flow much more naturally:
The Bool type is the coproduct of the terminal object with itself.
--huh?
The YesOrNoDataVariable is the coproduct of the terminal object with
itself.
--Oh! Of course!
--S
On Jan 18, 2009, at 12:17 PM, Benja Fallenstein wrote:
On Sun, Jan 18, 2009 at 5:48 PM, rocon...@theorem.ca wrote:
I noticed the Bool datatype isn't well documented. Since Bool is
not a
common English word, I figured it could use some haddock to help
clarify it
for newcomers.
-- |The Bool datatype is named after George Boole (1815-1864).
-- The Bool type is the coproduct of the terminal object with itself.
Russell, this does seem like it might be very helpful, but it might be
useful to include a note about what category you are working in.
People may sometimes naively assume that one is working in the
category of Haskell/Hugs/GHC data types and Haskell functions, in
which there are no terminal -- or initial -- objects ('undefined' and
'const undefined' are distinct maps between any two objects X and Y),
or else in the similar category without lifted bottoms, in which the
empty type is terminal and the unit type isn't ('undefined' and 'const
()' are both maps from any object X to the unit type). These niceties
will not confuse the advanced reader, but it may help the beginner if
you are more explicit.
- Benja
P.S. :-)
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Re: [Haskell-cafe] ANN: hledger 0.3 released
I was interested in actually using this for real, but unfortunately it seems like you have a dependency on the unix package. Would it be possible to use something portable (specifically to windows) instead? From: Simon Michael Sent: Saturday, January 17, 2009 11:42 PM To: hled...@googlegroups.com ; haskell-cafe@haskell.org Subject: [Haskell-cafe] ANN: hledger 0.3 released I'm pleased to announce another hledger release. Happy new year, all! hledger is a partial haskell clone of John Wiegley's ledger text-based accounting tool. It generates transaction balance reports from a plain text ledger file, and demonstrates a functional implementation of ledger. For more information, see hledger's home page: http://joyful.com/hledger News for 0.3 Fixes: * count timelog sessions on the day they end, like ledger, for now * when options are repeated, use the last instead of the first * builds with ghc 6.10 as well as 6.8 * runs much faster than 0.2:: $ bench hledger-0.2 hledger ledger || hledger-0.2 | hledger | ledger ==++=+=+=== -f 2008.ledger -s balance ||2.59 |0.26 | 0.11 -f 1entries.ledger -s balance || 566.68 |2.72 | 0.96 Features: * a simple ui for interactive report browsing: hledger ui * accept smart dates everywhere (MMDD, Y/M/D, Y, M/D, D, jan, today, last week etc.) * --period/-p flag accepting period expressions like in 2008, weekly from last month.. * -W/-M/-Y convenience flags to summarise register weekly, monthly, yearly * --depth and -E flags also affect summarised register reports (including depth=0) * --display/-d flag supporting date predicates (like d[DATE], d=[DATE]) * !include directive to include additional ledger files * !account directive to set a default parent account * Added support for reading historical prices from files * timelog and ledger entries can be intermixed in one file * modifier and periodic entries can appear anywhere (but are still ignored) * help and readme improvements Contributors: * Simon Michael * Nick Ingolia * Tim Docker * Corey O'Connor the vty team Stats: * Known errors: 1 * Tests: 58 * Lines of non-test code: 2123 Installation hledger requires GHC. It is known to build with 6.8 and 6.10. If you have cabal-install, do:: cabal update cabal install hledger Otherwise, unpack the latest tarball from http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hledger and do:: runhaskell Setup.hs configure runhaskell Setup.hs build sudo runhaskell Setup.hs install This will complain about any missing libraries, which you can download and install manually from hackage.haskell.org. (The Build-Depends: in hledger.cabal has the full package list.) To get the latest development code do:: darcs get http://joyful.com/repos/hledger ___ 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] Functors [Comments from OCaml Hacker Brian Hurt]
On Sun, 2009-01-18 at 11:23 +, Andrew Coppin wrote: Jonathan Cast wrote: On Sat, 2009-01-17 at 12:04 +, Andrew Coppin wrote: instance (Monad m) = Functor m where fmap f ma = do a - ma; return (f a) While that's quite interesting from a mathematical point of view, how is this useful for programming purposes? Good Lord. fmap (as above) is *at least* useful enough to be in the standard library! (Control.Monad.liftM). Given that liftM exists, why is having an identical implementation for fmap useful? What? jcc ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Functors [Comments from OCaml Hacker Brian Hurt]
On Sun, 2009-01-18 at 11:11 +, Andrew Coppin wrote: Heinrich Apfelmus wrote: Andrew Coppin wrote: instance (Monad m) = Functor m where fmap f ma = do a - ma; return (f a) While that's quite interesting from a mathematical point of view, how is this useful for programming purposes? Surely, you agree that liftM is useful? Because that's the same thing. Then why not just use liftM? (That way, you know what it does...) I'd be willing to say *you* don't `know what it does', if you haven't figured out that it's an acceptable implementation of fmap first. jcc ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: ANN: hledger 0.3 released
On 1/18/09 9:39 AM, Sebastian Sylvan wrote: I was interested in actually using this for real, but unfortunately it seems like you have a dependency on the unix package. Would it be possible to use something portable (specifically to windows) instead? Darn, thanks for the heads up. I guess we need to make the vty requirement (and ui command) optional. (I thought vty was cross-platform. :/) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Optimistic evaluation
andrewcoppin: Hi folks. I just read a rather interesting paper about a fork of GHC that performs optimistic evaluation. This shows big wins in some cases. The authors claim to have implemented this in a fork of GHC and promised that it would be integrated into the production compiler in the near future. Curios, I investigated the GHC wiki... Well, let's see now. The front page has links to out release plans for 6.8.3 and what will be in 6.10. The latter page, http://hackage.haskell.org/trac/ghc/wiki/Status/Releases mentions that a beta has just been released... and seems oblivious to the fact that 6.10.1 is production now. Clearly, any hopes I might have had of getting a handle on the current status of GHC from this wiki were dashed somewhat. ;-) Does anybody have any suggestions for a more reliable way of figuring out what the current activities and plans for GHC are? I'm assuming you're talking about the 'eager evaluation' papers? (There were a few). I think the verdict was that the runtime machinery was too complex for the performance gain. -- Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: ANN: hledger 0.3 released
Yeah looks like it depends on unix. Also, looks like the terminfo package isn't cross-platform either. Perhaps we need a better tool to mark packages which are platform-specific, so people don't accidentally use them, especially if they're a few levels away in the dependency graph. -- From: Simon Michael si...@joyful.com Sent: Sunday, January 18, 2009 6:08 PM To: Sebastian Sylvan sebastian.syl...@gmail.com Cc: hled...@googlegroups.com; haskell-cafe@haskell.org Subject: Re: ANN: hledger 0.3 released On 1/18/09 9:39 AM, Sebastian Sylvan wrote: I was interested in actually using this for real, but unfortunately it seems like you have a dependency on the unix package. Would it be possible to use something portable (specifically to windows) instead? Darn, thanks for the heads up. I guess we need to make the vty requirement (and ui command) optional. (I thought vty was cross-platform. :/) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] runghc Setup.hs doitall
On Sun, 2009-01-18 at 16:48 +, Sebastian Sylvan wrote: Doesn't work on windows. http://haskell.org/~duncan/cabal/cabal.exe It's not the latest version but you can use it to self-update. I'll post a more recent build after the next release. I might also put it in a slightly more discoverable place ;-) Duncan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] runghc Setup.hs doitall
On Sun, 2009-01-18 at 10:27 -0600, Jeff Wheeler wrote: On Sun, 2009-01-18 at 16:22 +, Sebastian Sylvan wrote: Is there some sort of bundle that you can use to install cabal-install easily? Because it looks to me like I'd have to spend the better part of an evening manually downloading and installing the gazillion of dependencies it has, which is far too much work when I just wanted to spend ten minutes playing with some package... There's a bootstrap.sh file in root of the cabal-install that can do this automatically. I've also improved the bootstrap.sh script for unix users. Feedback as to whether it still works on everyone's unix flavor would be much appreciated. http://darcs.haskell.org/cabal-install/bootstrap.sh It's slightly smarter about not re-installing things that are already installed. It should have rather better error handling too. In fact I've heard reports that this new one even works on Windows, though only for the people with MSYS of course. In my experience, it usually fails because of missing dependencies like zlib-dev on my own system, but those are easy to fix, at which point I can rerun the bootstrap script. Patches accepted. Duncan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] runghc Setup.hs doitall
On Sun, 2009-01-18 at 17:58 +0100, Daniel Fischer wrote: Am Sonntag, 18. Januar 2009 17:22 schrieb Sebastian Sylvan: Is there some sort of bundle that you can use to install cabal-install easily? Because it looks to me like I'd have to spend the better part of an evening manually downloading and installing the gazillion of dependencies it has, which is far too much work when I just wanted to spend ten minutes playing with some package... Wait, 'gazillion of dependencies'? If you have the extralibs bundle built, there are only three dependencies to take care of - a recent Cabal library - HTTP - zlib I think the problem is that hackage is misleading. It looks from the hackage page like there are a gazillion dependencies when in fact as you say there are only 2 that are not included with the latest ghc. The solution some have suggested would be for hackage to only list dependencies that are not in some core set. Duncan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] runghc Setup.hs doitall
On Sun, 2009-01-18 at 18:24 +, Duncan Coutts wrote: In my experience, it usually fails because of missing dependencies like zlib-dev on my own system, but those are easy to fix, at which point I can rerun the bootstrap script. Patches accepted. Without digressing too much, I don't think much can be done here. I would not (and should not) expect the bootstrap.sh file to use apt to get the missing dependencies as I had to do. I don't think there's any general solution to this, beyond better error handling (which apparently you just improved). Jeff Wheeler ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Improved documentation for Bool (Was: Comments from OCaml Hacker Brian Hurt)
Sterling Clover wrote: This is a great effort, but the root of the problem isn't just poor documentation, but an insistence on some obscure name. How about renaming Bool to YesOrNoDataVariable? I think this would help novice programmers a great deal. It would also make the documentation flow much more naturally: The Bool type is the coproduct of the terminal object with itself. --huh? The YesOrNoDataVariable is the coproduct of the terminal object with itself. --Oh! Of course! I'm sorry, but I don't get neither Bool nor YesOrNoDataVariable, it's too confusing for newcomers. Can we please name it to TerminalObjectCoSquared that's much more intuitive. Also, the wikipedia page http://en.wikipedia.org/wiki/YesOrNoDataVariable is extremely unhelpful. Not that the wikipedia page for Bool which links to http://en.wikipedia.org/wiki/Boolean_datatype is any better. The introduction goes to great lengths to note that For instance the ISO SQL:1999 standard defined a Boolean data type for SQL which could hold three possible values: true, false, unknown (SQL null is treated as equivalent to the unknown truth value, but only for the Boolean data type) What is SQL, do they mean the SesQuiLinear forms that I'm familiar with? But what does it have to do with TerminalObjectCoSquared? I'm confused. Regards, apfelmus -- http://apfelmus.nfshost.com ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] runghc Setup.hs doitall
duncan.coutts:
On Sun, 2009-01-18 at 17:58 +0100, Daniel Fischer wrote:
Am Sonntag, 18. Januar 2009 17:22 schrieb Sebastian Sylvan:
Is there some sort of bundle that you can use to install cabal-install
easily? Because it looks to me like I'd have to spend the better part of
an
evening manually downloading and installing the gazillion of dependencies
it has, which is far too much work when I just wanted to spend ten minutes
playing with some package...
Wait, 'gazillion of dependencies'? If you have the extralibs bundle built,
there are only three dependencies to take care of
- a recent Cabal library
- HTTP
- zlib
I think the problem is that hackage is misleading. It looks from the
hackage page like there are a gazillion dependencies when in fact as you
say there are only 2 that are not included with the latest ghc.
The solution some have suggested would be for hackage to only list
dependencies that are not in some core set.
Hmm. That's interesting. As we do in the distro tools, for example,
makedepends=('ghc=6.10.1' 'haskell-http4000' 'haskell-zlib')
http://repos.archlinux.org/viewvc.cgi/community/devel/cabal-install/PKGBUILD?revision=1.1root=communitypathrev=CURRENT
So the distro packaging tools already have the 'implicit set' of things
we know are on the system if ghc is on it too.
-- Don
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Re: [Haskell-cafe] runghc Setup.hs doitall
On a similar note, would it not be nice if cabal install understood about platforms and could tell you straight away that a package won't install under e.g. windows, rather then spending ages trying and then failing because a package tries to run a unix command? I always get a bit annoyed trying to do anything in windows with Haskell libraries, at the very least I'd like it to be clear from the start that something won't work (if it's by design) so I don't waste time trying. Ideally the hackage website would even allow you to filter packages by the OS you're using and would remove packages that won't build on that OS (by recursively checking dependencies too). -- From: Duncan Coutts duncan.cou...@worc.ox.ac.uk Sent: Sunday, January 18, 2009 6:20 PM To: Sebastian Sylvan sebastian.syl...@gmail.com Cc: Jeff Wheeler j...@nokrev.com; haskell-cafe@haskell.org Subject: Re: [Haskell-cafe] runghc Setup.hs doitall On Sun, 2009-01-18 at 16:48 +, Sebastian Sylvan wrote: Doesn't work on windows. http://haskell.org/~duncan/cabal/cabal.exe It's not the latest version but you can use it to self-update. I'll post a more recent build after the next release. I might also put it in a slightly more discoverable place ;-) Duncan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Comments from OCaml Hacker Brian Hurt
ross: On Sat, Jan 17, 2009 at 09:12:32PM -0500, a...@spamcop.net wrote: And FWIW, I agree with everyone who has commented that the documentation is inadequate. It'd be nice if there was some way to contribute better documentation without needing checkin access to the libraries. There is. The current state of the docs may be viewed at http://www.haskell.org/ghc/dist/current/docs/libraries/ Anyone can check out the darcs repos for the libraries, and post suggested improvements to the documentation to librar...@haskell.org (though you have to subscribe). It doesn't even have to be a patch. Sure, it could be smoother, but there's hardly a flood of contributions. I imagine if we set up a wiki-like system where the entire hackage docs could be edited, as well as viewed, we would end up with a flood. A modification to haddock perhaps, that sends edits to generated docs to libraries@ ? -- Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: ANNOUNCE: Coadjute 0.0.1, generic build tool
Henning Thielemann wrote: Matti Niemenmaa schrieb: Announcing the release of Coadjute, version 0.0.1! Web site: http://iki.fi/matti.niemenmaa/coadjute/ Hackage: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Coadjute snip How does it compare to http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hake Short answer: the question that comes to mind is how does hake compare to make? Coadjute seems to be more capable, in general, but then I don't know pretty much anything about hake. Somewhat longer answer: Coadjute is better in that: 1. hake's documentation is rather sparse. I have no idea what most functions do, or even what exactly the main program does. 2. hake doesn't seem to do parallel builds, but I'm not sure because of point 1. 3. Coadjute keeps track of command line arguments (see docs for details): for me this is really a killer feature, I don't know of anything else which does this. 4. hake always uses timestamps, Coadjute can use MD5 hashes as well. 5. Coadjute can have arbitrary path specifications, hake's rules seem to be based on file extensions only, thus applying only to the current directory. Peter Miller's Recursive Make Considered Harmful comes to mind: http://miller.emu.id.au/pmiller/books/rmch/ hake is better in that: 1. Its syntax is more concise. 2. It looks like it'd be easier to pick up for make users. 3. It seems to have some built-in support for more complex operations than Coadjute, e.g. the 'ruleSS' function. (Coadjute can still do this, just not as concisely. See point 1.) With the disclaimer that all I know about hake comes from its Hackage page and home page, which don't really tell me very much. I can't get any information out of the hake binary either: it doesn't respond to --help or similar. Much longer answer: I figured I'd convert the example there to Coadjute and see what happens. Result, with some inline comments: import Coadjute import System.FilePath (replaceExtension) import System.FilePath.Glob (globDir, compile) import System.Process (rawSystem) main = do -- assuming that hake's rules apply to the current directory only... ([sfx1, sfx2, c, cc, foo],_) - globDir (map compile [*.sfx1,*.sfx2,*.c,*.cc,foo*]) . coadjute $ do -- Coadjute doesn't offer arbitrary source/target pairing -- currently: it wants you to derive your targets from your -- sources somehow instead of just specifying them directly ruleM' greeting (\_ _ - run linker [-o,greeting,hello.o,good-bye.o]) (sourceToDatum (\_ - ( [good-bye.o] , [greeting,greeting.log] )) [hello.o]) rule' .sfx1 to .o (buildO compiler1) (sourceToDatum' (chExt o) sfx1) rule' .sfx2 to .o (buildO compiler2) (sourceToDatum' (chExt o) sfx2) -- Things like make clean don't really map well to Coadjute -- currently... -- -- Not only can it not be specified nicely, but the rule is always -- applied unless we have it create some kind of dummy file rule' clean (\_ _ - do run rm [-f, hello.o, good-bye.o , greeting, greeting.log] run touch [DUMMY]) (sourceToDatum' (const DUMMY) []) rule' .c to .o (\(s:_) _ - run gcc [-c, s]) (sourceToDatum' (chExt o) c) rule' .cc to .o (\(s:_) _ - run g++ [-c, s]) (sourceToDatum' (chExt O) cc) -- No equivalent to hake's ruleSS: deal with C/C++ dichotomy -- yourself rule' C++ .o to binaries (buildO g++) (sourceToDatum' (chExt ) $ map (chExt o) cc) rule' C .o to binaries (buildO gcc) (sourceToDatum' (chExt ) $ map (chExt o) c) ruleM' Not sure what this is (\[s] (t:_) - do gen - readFile s writeFile t $ unlines $ [ #!/bin/sh, echo This is script ] ++ lines gen) (sourceToDatum' (\s - [replaceExtension s gen, Hakefile]) foo) where chExt = flip replaceExtension run cmd args = rawSystem cmd args return () buildO compiler [s] t = run compiler [s,-o,t] I really don't know what that last rule (the one generated with the 'base' function in hake) is supposed to do. With no documentation I have absolutely no idea: my conversion above is my best guess, but I doubt I got it right. In any case, seems there are some things which hake's interface can do that Coadjute's can't: 1. Arbitrary source/target pairing. This was really a d'oh moment for me and is trivial to fix. I think I'll even remove the current sourceToDatum functions and just provide a primitive with which you can map, fold, whatever.
Re: [Haskell-cafe] runghc Setup.hs doitall
On Sun, 2009-01-18 at 12:28 -0600, Jeff Wheeler wrote: On Sun, 2009-01-18 at 18:24 +, Duncan Coutts wrote: In my experience, it usually fails because of missing dependencies like zlib-dev on my own system, but those are easy to fix, at which point I can rerun the bootstrap script. Patches accepted. Without digressing too much, I don't think much can be done here. I would not (and should not) expect the bootstrap.sh file to use apt to get the missing dependencies as I had to do. I don't think there's any general solution to this, beyond better error handling (which apparently you just improved). It'll still fall over when it fails to find the zlib C lib. That's a slightly more general issue: Check for required C libraries during configure http://hackage.haskell.org/trac/hackage/ticket/262 Again, patches gratefully accepted :-) Duncan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] runghc Setup.hs doitall
On Sun, 2009-01-18 at 18:35 +, Sebastian Sylvan wrote: On a similar note, would it not be nice if cabal install understood about platforms and could tell you straight away that a package won't install under e.g. windows, rather then spending ages trying and then failing because a package tries to run a unix command? We're pretty near to that. It does understand platforms. What we lack is in the information that it does not work. We can get it in two ways. One is if we cannot find sh.exe then we know straight away that all configure based packages will not work. We should be able to do similar things for packages that need C libs headers etc that we cannot find. We should only need manual additional info for a few packages. The tickets in this context are: http://hackage.haskell.org/trac/hackage/ticket/342 http://hackage.haskell.org/trac/hackage/ticket/400 I always get a bit annoyed trying to do anything in windows with Haskell libraries, at the very least I'd like it to be clear from the start that something won't work (if it's by design) so I don't waste time trying. Ideally the hackage website would even allow you to filter packages by the OS you're using and would remove packages that won't build on that OS (by recursively checking dependencies too). Yes, we should be able to use the same info on hackage as in cabal-install. So, as usual the limiting factor is the number of people hacking on the infrastructure. Time to get involved! :-) Duncan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: ANN: hledger 0.3 released
I've pushed a patch which should omit the vty dependency and ui command on windows. Sebastian, could you darcs get the latest code from http://joyful.com/repos/hledger and see if cabal configure and build works for you on windows ? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: Improved documentation for Bool (Was: [Haskell-cafe] Comments from OCaml Hacker Brian Hurt)
That's a great start, but coproduct is still pretty scary. Why not refer
to it as OneOrTheOtherButNotBothDataConstructor?
-Nathan Bloomfield
On Sun, Jan 18, 2009 at 11:32 AM, Sterling Clover s.clo...@gmail.comwrote:
This is a great effort, but the root of the problem isn't just poor
documentation, but an insistence on some obscure name. How about renaming
Bool to YesOrNoDataVariable? I think this would help novice programmers a
great deal.
It would also make the documentation flow much more naturally:
The Bool type is the coproduct of the terminal object with itself.
--huh?
The YesOrNoDataVariable is the coproduct of the terminal object with
itself.
--Oh! Of course!
--S
On Jan 18, 2009, at 12:17 PM, Benja Fallenstein wrote:
On Sun, Jan 18, 2009 at 5:48 PM, rocon...@theorem.ca wrote:
I noticed the Bool datatype isn't well documented. Since Bool is not a
common English word, I figured it could use some haddock to help clarify
it
for newcomers.
-- |The Bool datatype is named after George Boole (1815-1864).
-- The Bool type is the coproduct of the terminal object with itself.
Russell, this does seem like it might be very helpful, but it might be
useful to include a note about what category you are working in.
People may sometimes naively assume that one is working in the
category of Haskell/Hugs/GHC data types and Haskell functions, in
which there are no terminal -- or initial -- objects ('undefined' and
'const undefined' are distinct maps between any two objects X and Y),
or else in the similar category without lifted bottoms, in which the
empty type is terminal and the unit type isn't ('undefined' and 'const
()' are both maps from any object X to the unit type). These niceties
will not confuse the advanced reader, but it may help the beginner if
you are more explicit.
- Benja
P.S. :-)
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[Haskell-cafe] Stupid question, re: overloaded type classes
So, I'm working with this simplistic S-expression library of my own design (yes, I know, reinventing the wheel). Basically, I have the type: data Sexp = List of [ Sexp ] | Atom of String with the associated parsers and printers which really aren't relevent to the question at hand. Then, I want to define the type class of types I can convert to and from s-expressions, like: class Sexpable a where toSexp :: a - Sexp fromSexp :: Sexp - Maybe a here, fromSexp can return Nothing is the s-expression isn't the right form to be parsed into a whatever. Now, here's the problem. I want to define a bunch of default instances, and two in particular I want to define are: instance Sexpable String where toSexp s = Atom s fromSexp (Atom s) = Just s fromSexp _ = Nothing instance Sexpable a = Sexpable [ a ] where toSexp lst = List $ map toSexp lst fromSexp (List lst) = mapM fromSexp lst fromSexp _ = Nothing Note that I am not implementing Sexpable Char anywhere, so the only valid transform for [Char] should be the String one. But this still causes a compiler error due to the overloaded instances on [Char]. There are two solutions to this that I already know of. One is to play games with newtype, which I don't like because it simply adds complexity in my case and doesn't help anything else. The second possibility is to compile with -fallow-incoherent-instances, which I'm slightly afraid of because I'm not sure what (if any) possible errors adding this option might allow. So my question is twofold: 1) what errors might be allowed if I add -fallow-incoherent-instances, and 2) is there some third choice that avoids both solutions I already know about? Thanks. Brian ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: Improved documentation for Bool (Was: [Haskell-cafe] Comments from OCaml Hacker Brian Hurt)
On Sun, 2009-01-18 at 18:17 +0100, Benja Fallenstein wrote: On Sun, Jan 18, 2009 at 5:48 PM, rocon...@theorem.ca wrote: I noticed the Bool datatype isn't well documented. Since Bool is not a common English word, I figured it could use some haddock to help clarify it for newcomers. -- |The Bool datatype is named after George Boole (1815-1864). -- The Bool type is the coproduct of the terminal object with itself. Russell, this does seem like it might be very helpful, but it might be useful to include a note about what category you are working in. People may sometimes naively assume that one is working in the category of Haskell/Hugs/GHC data types and Haskell functions, in which there are no terminal -- or initial -- objects The naive way of making a Haskell category doesn't even work. Taking objects to be Haskell types, all Haskell functions as arrows, arrow equality being observational equality, and (.) and id to be the composition and identity, you fail to even have a category. Proof of this is left as an (easy) exercise for the reader. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: ANNOUNCE: Coadjute 0.0.1, generic build tool
Matti Niemenmaa schrieb: Anyway, hake looks interesting but it's not a replacement for Coadjute; and neither is Coadjute for hake. To be completely honest I'm not sure what use case hake is meant to solve: how does it improve over plain make? It seems to be programmable, and thus may better cope with LaTeX, where the simple 'make' philosophy fails. 'latex' must be called repeatedly, interleaved with 'bibtex' and 'mkindex'. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Stupid question, re: overloaded type classes
On Sun, Jan 18, 2009 at 11:23 AM, Brian Hurt bh...@spnz.org wrote: instance Sexpable String where instance Sexpable a = Sexpable [ a ] where Note that I am not implementing Sexpable Char anywhere, so the only valid transform for [Char] should be the String one. But this still causes a compiler error due to the overloaded instances on [Char]. So my question is twofold: 1) what errors might be allowed if I add -fallow-incoherent-instances, and 2) is there some third choice that avoids both solutions I already know about? 1) Incoherent instances end up being used in code like this: blah :: Sexpable a = a - Sexp blah x = toSexp [x] In this case, assuming an instance for Sexpable Char, this code may or may not use the wrong instance, depending on what happens with inlining: blah 'x' which passes the dictionary for Sexpable Char and then probably uses the instance Sexpable a = Sexpable [a] (with a = Char), instead of Sexpable String. As long as there are no instances for Sexpable Char anywhere, incoherent instances won't cause an error in this case. That said, you can't guarantee that someone won't go and add an instance for Char. 2) A third choice is to do what Show does, which is kind of a hack but solves this specific problem: class Sexpable a where toSexp :: a - Sexp fromSexp :: Sexp - Maybe a toSexpList :: [a] - Sexp fromSexpList :: Sexp - Maybe [a] toSexpList = List . map toSexp fromSexpList (List lst) = mapM fromSexp lst fromSexpList _ = Nothing instance Sexpable a = Sexpable [a] where toSexp = toSexpList -- from Sexpable a, not [a] fromSexp = fromSexpList This requires Sexpable Char, though, to give you the right place to put the instance. But it seems easy enough to include those; is there a reason you explicitly don't want an instance for Char? instance Sexpable Char where toSexp c = toSexpList [c] fromSexp l = do [c] - fromSexp l return c toSexpList s = Atom s fromSexpList (Atom s) = Just s fromSexpList _ = Nothing I think that a design for typeclasses that eliminates the need for the showList hack would be quite welcome. -- ryan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Stupid question, re: overloaded type classes
On Sun, Jan 18, 2009 at 12:43 PM, sam lee skyn...@gmail.com wrote: The following code compiles fine on my ghci This seems like a bug, you didn't enable overlapping instances and these two instances clearly overlap: instance Sexpable String where instance Sexpable a = Sexpable [ a ] where since String is a synonym for [Char]. Although maybe overlapping doesn't get checked until you use the instance? Try adding this line: test = toSexp hello -- ryan -- ryan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] meeep
apologies for the old-digest copy spam. . Louis Wasserman wasserman.lo...@gmail.com ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Anybody in Savannah?
Hi, I arrived in Savannah yesterday (to attend PADL), and have spent the most part of the day drifting aimlessly around. Thrilling as that may be, I thought perhaps there might be other members of the Haskell community around, and that perhaps we could arrange to meet informally for coffee, beer, dinner? -k -- If I haven't seen further, it is by standing in the footprints of giants ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Anybody in Savannah?
ketil: Hi, I arrived in Savannah yesterday (to attend PADL), and have spent the most part of the day drifting aimlessly around. Thrilling as that may be, I thought perhaps there might be other members of the Haskell community around, and that perhaps we could arrange to meet informally for coffee, beer, dinner? Some Galwegians will be at POPL and related events. http://www.galois.com/blog/2009/01/18/galois-at-popl/ Say hi to them :) -- Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Comments from OCaml Hacker Brian Hurt
2009/1/18 Don Stewart d...@galois.com: ross: On Sat, Jan 17, 2009 at 09:12:32PM -0500, a...@spamcop.net wrote: And FWIW, I agree with everyone who has commented that the documentation is inadequate. It'd be nice if there was some way to contribute better documentation without needing checkin access to the libraries. There is. The current state of the docs may be viewed at http://www.haskell.org/ghc/dist/current/docs/libraries/ Anyone can check out the darcs repos for the libraries, and post suggested improvements to the documentation to librar...@haskell.org (though you have to subscribe). It doesn't even have to be a patch. Sure, it could be smoother, but there's hardly a flood of contributions. I imagine if we set up a wiki-like system where the entire hackage docs could be edited, as well as viewed, we would end up with a flood. A modification to haddock perhaps, that sends edits to generated docs to libraries@ ? This has come up many times lately. I've created a ticket for it: http://trac.haskell.org/haddock/ticket/72 If anyone has suggestions for design or implementation of a system like this, don't hesitate to post to this ticket! David ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Comments from OCaml Hacker Brian Hurt
david.waern: 2009/1/18 Don Stewart d...@galois.com: ross: On Sat, Jan 17, 2009 at 09:12:32PM -0500, a...@spamcop.net wrote: And FWIW, I agree with everyone who has commented that the documentation is inadequate. It'd be nice if there was some way to contribute better documentation without needing checkin access to the libraries. There is. The current state of the docs may be viewed at http://www.haskell.org/ghc/dist/current/docs/libraries/ Anyone can check out the darcs repos for the libraries, and post suggested improvements to the documentation to librar...@haskell.org (though you have to subscribe). It doesn't even have to be a patch. Sure, it could be smoother, but there's hardly a flood of contributions. I imagine if we set up a wiki-like system where the entire hackage docs could be edited, as well as viewed, we would end up with a flood. A modification to haddock perhaps, that sends edits to generated docs to libraries@ ? This has come up many times lately. I've created a ticket for it: http://trac.haskell.org/haddock/ticket/72 If anyone has suggestions for design or implementation of a system like this, don't hesitate to post to this ticket! Added to the entry on the proposals tracker, http://www.reddit.com/r/haskell_proposals/ If nothing else, this would make a good SoC project. -- Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Anybody in Savannah?
Hi, I arrived in Savannah yesterday (to attend PADL), and have spent the most part of the day drifting aimlessly around. Thrilling as that may be, I thought perhaps there might be other members of the Haskell community around, I will be, in about three hours. Plans for tonight: sleeping :-) But maybe see you tomorrow? Janis ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] real haskell difficulties (at least for me)
2009/1/18 Duncan Coutts duncan.cou...@worc.ox.ac.uk: Second, and this would take more work, I would like it if the Haddock documentation for packages could be given a wiki-like and/or reddit-like interface so that people could make comments about what is unclear or needs better documentation as well as offering spelling/grammar/punctuation suggestions[2]. Viewers should be able to set preferences for whether they want to see the real/current documentation, or whether they want to see the commented/modified version (hiding things below a certain depth or rank for reddit-like). We had a thread on this the other day with similar ideas. It might not count as a summary, since I'm not sure I've read all of the discussion, but I added a ticket describing this type of system here: http://trac.haskell.org/haddock/ticket/72 If something is missing, please add it, and feel free to post more thoughts. David ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Anybody in Savannah?
vo...@tcs.inf.tu-dresden.de writes: I will be, in about three hours. Plans for tonight: sleeping :-) Boring! But maybe see you tomorrow? Sure! I got some replies, so hopefully my evening won't be entirely solitary. For anybody else who didn't have time to respond, I'll stroll down in the lobby of the conference hotel as of now, and hang around for the next hour or so. Feel free to meet up. -k -- If I haven't seen further, it is by standing in the footprints of giants ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Different return type?
Hi,
Possibly a silly question but is it possible to have a function that has a
different return type based on it's first argument?
For instance
data Person = Person { name :: String, ... }
data Business = Business { business_number :: Int, ...}
key person = name person
key business = business_number business
Thanks
-John
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Re: [Haskell-cafe] Stupid question, re: overloaded type classes
On Sun, 18 Jan 2009, Ryan Ingram wrote: 2) A third choice is to do what Show does, which is kind of a hack but solves this specific problem: Thanks. I like this solution much better than the two I proposed. Brian ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Different return type?
Am Montag, 19. Januar 2009 02:44 schrieb John Ky:
Hi,
Possibly a silly question but is it possible to have a function that has a
different return type based on it's first argument?
For instance
data Person = Person { name :: String, ... }
data Business = Business { business_number :: Int, ...}
key person = name person
key business = business_number business
Thanks
-John
Well, you could use
{-# LANGUAGE MultiParamTypeClasses, FunctionalDependencies,
TypeSynonymInstances #-}
module Key where
data Person = Person { name :: String }
data Business = Business { business_number :: Int}
class Key a b | a - b where
key :: a - b
instance Key Person String where
key = name
instance Key Business Int where
key = business_number
or with type families:
{-# LANGUAGE TypeFamilies #-}
class Key2 a where
type Res a
key2 :: a - Res a
instance Key2 Person where
type Res Person = String
key2 = name
instance Key2 Business where
type Res Business = Int
key2 = business_number
but apart from that and parametrically polymorphic functions (of type a - [a]
or the like), I don't think it's possible, it would need dependent types.
HTH,
Daniel
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Re: [Haskell-cafe] Re: ANNOUNCE: Coadjute 0.0.1, generic build tool
On 2009 Jan 18, at 13:47, Matti Niemenmaa wrote: 3. Coadjute keeps track of command line arguments (see docs for details): for me this is really a killer feature, I don't know of anything else which does this. It's been done many times before; it never seems to catch on. My personal favorite was Shape (http://user.cs.tu-berlin.de/~shape/) which I used for a few local projects in the late 80s. SCons is perhaps the most popular tool in this class (and itself a Pythonization of the original Perl Cons; maybe it's time for HCons?), followed by Apache's Ant (I don't think that actually caches command lines or binaries though), then Jam and successors. -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon universityKF8NH ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Different return type?
Hi Daniel,
When would I use either? What are the trade-offs?
Thanks
-John
On Mon, Jan 19, 2009 at 1:13 PM, Daniel Fischer daniel.is.fisc...@web.dewrote:
Am Montag, 19. Januar 2009 02:44 schrieb John Ky:
Hi,
Possibly a silly question but is it possible to have a function that has
a
different return type based on it's first argument?
For instance
data Person = Person { name :: String, ... }
data Business = Business { business_number :: Int, ...}
key person = name person
key business = business_number business
Thanks
-John
Well, you could use
{-# LANGUAGE MultiParamTypeClasses, FunctionalDependencies,
TypeSynonymInstances #-}
module Key where
data Person = Person { name :: String }
data Business = Business { business_number :: Int}
class Key a b | a - b where
key :: a - b
instance Key Person String where
key = name
instance Key Business Int where
key = business_number
or with type families:
{-# LANGUAGE TypeFamilies #-}
class Key2 a where
type Res a
key2 :: a - Res a
instance Key2 Person where
type Res Person = String
key2 = name
instance Key2 Business where
type Res Business = Int
key2 = business_number
but apart from that and parametrically polymorphic functions (of type a -
[a]
or the like), I don't think it's possible, it would need dependent types.
HTH,
Daniel
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