July 2005 - template-haskell

record accessor names
by Rene de Visser 25 Jul '05

25 Jul '05

Hello, Am I correct in thinking that with reify that I can not find the names of the read/write accessors rel1 and rel2 from the following? data SmallDB = SmallDB { rel1 :: Set.Set String , rel2 :: Set.Set Integer } deriving Show I thought about quoting the above and splicing it in, but as you can't quote and splice back into the same module and due to type dependencies this could result in a mess of recursive modules. I also though of generating the above from a union type. i.e. using data SmallDB = DBREL1 String | DBREL2 Integer to generate the above. Then I would know the names of the accessors. However I think it is not possible to have type dependencies based on data constuctors? Actually, is this what GADT's allow one to do? Does template haskell support GADT's`? i.e. with reify and syntax structure wise? Rene.

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reify: how to show the result.
by Rene de Visser 19 Jul '05

19 Jul '05

I guess this is easy, but I am not managing it. I have data SmallDB = SmallDB { rel1 :: Set.Set String , rel2 :: Set.Set Integer } deriving Show and wish to see the results of reify 'SmallDB which I need to evaluate this at compile time. test212 data_con = do; (DataConI _ typ _ _) <- runQ (reify data_con); print typ test214 data_con = do; string <- runIO $ test212 data_con; return string Which I now need to splice in test213 = $(test214 'SmallDB) so that I can run test213 to see the result. How do I write test214 so that it has the correct result type? What does report do? Can I use it to print out the result? Why does the Info type not support the type class show? Rene.

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Early registration: GPCE'05 -- Generative Programming and Component Engineering
by Eelco Visser 15 Jul '05

15 Jul '05

CALL for EARLY REGISTRATION (deadline July 29) ---------------------------------------------------------------------- 4th International Conference on Generative Programming and Component Engineering (GPCE'05) Sep 29 - Oct 1, 2005, Tallinn (Estonia) http://www.gpce.org/05 Sponsored by ACM SIGPLAN, in cooperation with ACM SIGSOFT co-located with ICFP'05 and TFP'05 ---------------------------------------------------------------------- Please consult http://www.gpce.org/05 for the UP-TO-DATE and DETAILED programme http://www.cs.ioc.ee/tfp-icfp-gpce05/ for the ON-LINE REGISTRATION, hotel and travel information ---------------------------------------------------------------------- IMPORTANT DATES * Jul 29, 2005: EARLY REGISTRATION DEADLINE (and hotel discount rates) * Sep 02, 2005: Late registration deadline * Sep 27-28, 2005: GPCE workshops and tutorials * Sep 29 - Oct 1, 2005: GPCE papers and demos ---------------------------------------------------------------------- SCOPE. Generative and component approaches have the potential to revolutionize software development in a similar way as automation and components revolutionized manufacturing. Generative Programming (developing programs that synthesize other programs), Component Engineering (raising the level of modularization and analysis in application design), and Domain-Specific Languages (elevating program specifications to compact domain-specific notations that are easier to write and maintain) are key technologies for automating program development. GPCE arose as a joint conference, merging the conference on Generative and Component-Based Software Engineering (GCSE) and the workshop on Semantics, Applications, and Implementation of Program Generation (SAIG). The goal of GPCE is to provide a meeting place for researchers and practitioners interested in cutting edge approaches to software development. We aim to foster further cross-fertilization between the software engineering research community and the programming languages community, in addition to supporting the original research goals of both the GCSE and the SAIG communities. ---------------------------------------------------------------------- 3 INVITED SPEAKERS: * Oscar Nierstrasz: Object-oriented Reengineering Patterns * Oege de Moor: The AspectBench Compiler for AspectJ * Bernd Fischer: Certifiable Program Generation 25 TECHNICAL PAPERS 2 DEMONSTRATIONS: * Developing Dynamic and Adaptable Applications with CAM/DAOP: a Virtual Office Application * Metamodeling made easy - MetaEdit+ 2 TUTORIALS T1: Multi-stage Programming in MetaOCaml (Presenters: W.Taha, C.Calcagno) T2: Implementing Domain-Specific Modelling Languages and Generators (Presenters: R.Pohjonen and J-P.Tolvanen) 3 WORKSHOPS W1: Seventh Young Researchers Workshop (Organizers: D.R.Dechow, D.Foetsch, S.Kiebusch, S.Perugini, M.J.Rutherford, D.Shestakov) W2: Second MetaOCaml Workshop (Organizers: K.Swadi, W.Taha) W3: Graph and Model Transformations Workshop (Organizers: G.Karsai, G.Taentzer) ---------------------------------------------------------------------- PROGRAM COMMITTEE Chairs: * Robert Glück (U. of Copenhagen) * Michael Lowry (NASA) Members: * Don Batory (U. of Texas, USA) * Ira Baxter (Semantic Designs) * Cristiano Calcagno (Imperial College) * Prem Devanbu (U. of California at Davis) * Ulrich Eisenecker (U. of Leipzig) * Tom Ellman (Vassar College) * Robert Filman (NASA) * Zhenjiang Hu (U. of Tokyo) * Patricia Johann (Rutgers U.) * John Launchbury (Galois) * Anne-Françoise Le Meur (U. of Sci. and Tech. Lille) * Hong Mei (Peking U.) * Nicolas Rouquette (NASA) * William Scherlis (CMU) * Yannis Smaragdakis (Georgia Inst. of Tech.) * Walid Taha (Rice U.) * Todd Veldhuizen (Chalmers U. of Tech.) ORGANIZING COMMITTEE General Chair * Eugenio Moggi (Genova U.) Publicity Chair: * Eelco Visser (U. Utrecht) Workshops and Tutorials Chairs * Jeff Gray (U. of Alabama at Birmingham) * Andrew Malton (Waterloo U.) Local Arrangements Chair * Tarmo Uustalu (Inst. of Cybernetics, Tallinn) ----------------------------------------------------------------------

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FW: [Template-haskell] Records and generating splices
by Rene de Visser 12 Jul '05

12 Jul '05

>From: "Rene de Visser" <rene_de_visser(a)hotmail.com> >test9 = [d| add_rel1 value = $(exp) value |] where > exp = [| (\value -> modify (\db -> $(updater) db (Set.insert >value (rel1 db)))) |] where > updater = [|(\db value -> db{rel1 = value}) |] > --updater = LamE [VarP db_2,VarP value_3] (RecUpdE (VarE db_2) >[(DataBase.rel1,VarE value_3)]) where > db_2 = mkName "db_2" ; value_3 = mkName "value_3" Ok, I've found the error, that needs to be updater = lamE [varP db_2,varP value_3] (recUpdE (varE db_2) [fieldExp 'DataBase.rel1 (varE value_3)]) Rene.

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FW: [Template-haskell] Records and generating splices
by Rene de Visser 11 Jul '05

11 Jul '05

>From: "Rene de Visser" <rene_de_visser(a)hotmail.com> >test = [| add_rel1 value = modify (\db -> db{ rel1 = Set.insert value (rel1 >db)}) |] >{-# OPTIONS -fglasgow-exts #-} >module DataBase where > >import Control.Monad.State >import qualified Data.Set as Set >-- Does this really need to be extensible??? >-- Entries need to be based on sets, or something similar... >data SmallDB = SmallDB { rel1 :: Set.Set String > , rel2 :: Set.Set Integer } deriving Show > >emptyDB = SmallDB Set.empty Set.empty > >add_rel1 :: (MonadState SmallDB m) => String -> m () >add_rel1 value = modify (\db -> db{ rel1 = Set.insert value (rel1 db)}) > >add_rel2 :: (MonadState SmallDB m) => Integer -> m () >add_rel2 value = modify (\db -> db{ rel2 = Set.insert value (rel2 db)}) > So I've made a tiny bit of progress. I have: test9 = [d| add_rel1 value = $(exp) value |] where exp = [| (\value -> modify (\db -> $(updater) db (Set.insert value (rel1 db)))) |] where updater = [|(\db value -> db{rel1 = value}) |] --updater = LamE [VarP db_2,VarP value_3] (RecUpdE (VarE db_2) [(DataBase.rel1,VarE value_3)]) where db_2 = mkName "db_2" ; value_3 = mkName "value_3" However if I replace updater by its expansion, I get a type error. Why? It looks like an expansion of a quasi quote is not identical to the quasi quote? Rene.

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RE: [Template-haskell] Profiling with Template Haskell, again
by Simon Marlow 11 Jul '05

11 Jul '05

Also, you need to compile each module in the program twice: once unprofiled, for running TH splices, and once profiled for the final executable. We'd probably need some new flags to GHC to handle this. The TH linker needs to know to link in the unprofiled object files, but the compilation manager needs to generate profiled object files, so we need two separate object suffices. We already have -osuf, so perhaps we need -th-osuf (and hence -th-hisuf). But that's not all. You could get into trouble if the .hi files differed between the profiled and unprofiled versions of modules, because GHC assumes they're the same. I haven't thought through exactly what could go wrong if they're different, but we're definitely on shaky ground here. Compiling without optimisation will probably be necessary, but then that degrades the usefulness of profiling. Cheers, Simon On 11 July 2005 12:44, Simon Peyton-Jones wrote: > Here's a Template Haskell problem. When compiling with -prof, you > want to link with *profiled* libraries for the final executable, but > with *ordinary, unprofiled* libraries for the TH libs that are linked > with GHC itself. > > There is nothing truly hard about implementing this, but it's fiddly. > This message has been sitting in my mailbox for more than two months, > so I'm plainly not getting to it. To unblock, would anyone like to > volunteer to have a go? I can tell you where to look. > > Simon > >> -----Original Message----- >> From: template-haskell-bounces(a)haskell.org > [mailto:template-haskell-bounces@haskell.org] On >> Behalf Of Andre Pang >> Sent: 25 April 2005 15:42 >> To: <template-haskell(a)haskell.org> <template-haskell(a)haskell.org> >> Cc: Sean Seefried >> Subject: [Template-haskell] Profiling with Template Haskell, again >> >> Hi all, >> >> I've run into the same problem as Sean Seefried, namely that I'd like >> to profile executables built with Template Haskell: >> >> > http://www.haskell.org/pipermail/template-haskell/2003-July/000135.html >> >> (Specifically, profiling the final executable, not the splicing.) >> >> I guess this is just a simple message to say that there's someone >> else asking for profiling support with TH now, in the hopes that >> it'll bump up its priority on the ever-growing to-do list :). >> >> Thanks, >> >> >> -- >> % Andre Pang : trust.in.love.to.save <http://www.algorithm.com.au/> >> >> _______________________________________________ >> template-haskell mailing list >> template-haskell(a)haskell.org >> http://www.haskell.org/mailman/listinfo/template-haskell > _______________________________________________ > template-haskell mailing list > template-haskell(a)haskell.org > http://www.haskell.org/mailman/listinfo/template-haskell

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RE: [Template-haskell] Avoiding linking final executable to TH
by Simon Peyton-Jones 11 Jul '05

11 Jul '05

Einar raises another TH-linking question: how to avoid linking the TH libraries (which are needed at compile time) into the runtime executable. The difficulty is that GHC doesn't know for sure that you aren't going to need the libraries at runtime too. If you do a batch link step ghc -o foo This.o That.o Main.o -package mylib does that work ok? Is the problem only with --make? I'm reluctant to have two kinds of imports. Other ideas welcome. Better still, someone willing to take up the cudgels. Again, once the specification is clear, we can offer guidance. Simon | -----Original Message----- | From: template-haskell-bounces(a)haskell.org [mailto:template-haskell-bounces@haskell.org] On | Behalf Of Einar Karttunen | Sent: 04 July 2005 09:48 | To: template-haskell(a)haskell.org | Subject: [Template-haskell] Avoiding linking final executable to TH | | Hello | | Are there currently any plans to avoid linking the final executable with | TH? As far as I understand currently the situation is as follows: | | Module M uses TH code defined in MTH. | Module MTH imports TH modules and thus needs to be linked with template-haskell. | | The simplest way to deal with this could be to use a special | compile-time import construct between M and MTH - so that MTH would | not need to be linked with M (and thus template-haskell would not be | needed either). | | Are there any plans regarding something like this or an another solution? | | - Einar Karttunen | _______________________________________________ | template-haskell mailing list | template-haskell(a)haskell.org | http://www.haskell.org/mailman/listinfo/template-haskell

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RE: [Template-haskell] Profiling with Template Haskell, again
by Simon Peyton-Jones 11 Jul '05

11 Jul '05

Here's a Template Haskell problem. When compiling with -prof, you want to link with *profiled* libraries for the final executable, but with *ordinary, unprofiled* libraries for the TH libs that are linked with GHC itself. There is nothing truly hard about implementing this, but it's fiddly. This message has been sitting in my mailbox for more than two months, so I'm plainly not getting to it. To unblock, would anyone like to volunteer to have a go? I can tell you where to look. Simon | -----Original Message----- | From: template-haskell-bounces(a)haskell.org [mailto:template-haskell-bounces@haskell.org] On | Behalf Of Andre Pang | Sent: 25 April 2005 15:42 | To: <template-haskell(a)haskell.org> <template-haskell(a)haskell.org> | Cc: Sean Seefried | Subject: [Template-haskell] Profiling with Template Haskell, again | | Hi all, | | I've run into the same problem as Sean Seefried, namely that I'd like | to profile executables built with Template Haskell: | | http://www.haskell.org/pipermail/template-haskell/2003-July/000135.html | | (Specifically, profiling the final executable, not the splicing.) | | I guess this is just a simple message to say that there's someone else | asking for profiling support with TH now, in the hopes that it'll bump | up its priority on the ever-growing to-do list :). | | Thanks, | | | -- | % Andre Pang : trust.in.love.to.save <http://www.algorithm.com.au/> | | _______________________________________________ | template-haskell mailing list | template-haskell(a)haskell.org | http://www.haskell.org/mailman/listinfo/template-haskell

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is this (.csv) a good task for template-haskell?
by Lloyd Allison 11 Jul '05

11 Jul '05

I'd like to write some Haskell programs to manipulate comma-separated variable, .csv, files from a spreadsheet. The obvious way to start which, for perverse(?) reasons, I do not want to follow is to create a union type e.g. data CSVelement = I int | S string | ... or similar. All the elements of a given column will be of the same type e.g. bool, int, float, string, or a-selection-of-names (e.g. {Lab, Con, LibDem}). (and some columns with missing values). e.g. "Homer",42,67.8,Lab "Paris",,5.5,Con ... I'd like to write some code that 1. takes a quick look at the file, counts the columns, works out the type of each column (including creating data T1 = Lab|Con|LibDem, and using `Maybe' for missing values), 2. creates a tuple-type for a row, e.g. (String, Maybe Int, Float, T1), and adds that type to Reads, Show (and some other stuff), and 3. then gets on with processing the data. Is template-Haskell a good choice for this task and, if so, what is the quickest way to get started? (Or has it been done?) -Lloyd -- Lloyd ALLISON, CSSE, Monash University, Victoria, Australia 3800. web: http://www.csse.monash.edu.au/~lloyd/ tel: +61 3 9905 5205

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RE: [Template-haskell] Splicing bindings
by Simon Peyton-Jones 11 Jul '05

11 Jul '05

Sadly no. Ideally one would like to be able to splice in *any* syntactic construct, but at present implementing each requires separate work in the implementation, and it's especially tricky if the construct can bind things (such as declarations, patterns, and do-statements). Again, you can do it "by steam" using the lower-level constructors... it's just more clumsy. Simon | -----Original Message----- | From: template-haskell-bounces(a)haskell.org [mailto:template-haskell-bounces@haskell.org] On | Behalf Of Mike Gunter | Sent: 13 June 2005 06:24 | To: template-haskell(a)haskell.org | Subject: [Template-haskell] Splicing bindings | | | Is there a way to splice in a | | nm <- m | | binding? I.e., I'd like something along the lines of | mdo | ... | $(defNm nm m) | ... | ... nm ... | ... | | which would expand to | | mdo | ... | nm <- name "nm" m | ... | ... nm ... | ... | | . Is this possible? | | thanks, | mike | _______________________________________________ | template-haskell mailing list | template-haskell(a)haskell.org | http://www.haskell.org/mailman/listinfo/template-haskell

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