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[Haskell][ANN] vabal - the cabal companion
by Francesco Magliocca 28 Dec '18

28 Dec '18

Hello, I'm please to announce that vabal 1.2.0 has been released on Hackage: http://hackage.haskell.org/package/vabal vabal is a software that helps you determine the ghc version needed to compile a cabal package. It reads the cabal file and extracts the constraints imposed on the base package. Then it uses ghcup ( https://github.com/haskell/ghcup ) to obtain a compiler version compatible with the constraints (possibly downloading it from the official ghc mirror) and can be combined with cabal to build the project using the obtained ghc compiler. In this way you can treat the `base` package dependency as any other package dependency and don't have to manually deal with different ghc versions anymore. vabal is meant to be used in collaboration with cabal. It leverages cabal's ability to work with multiple ghc versions, and tries to be the least intrusive possible, so that you can keep using your usual workflow, but won't have to worry about `base` package dependency issues, anymore. You can get started here: https://github.com/Franciman/vabal#quick-start For details please refer to: https://github.com/Franciman/vabal#vabal---the-cabal-companion Ideas, suggestions, opinions and pull requests are very welcome! A big thank you goes to all the contributors that helped me with code, suggestions and ideas: https://github.com/Franciman/vabal#contributors

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Find out which part of code are causing parallelism?
by ducis 28 Dec '18

28 Dec '18

Hi all, I am working on parallelising some program, however I just found out that without inserting any parallism manually the program is already parallelised, presumably by some of the libraries referenced, as long as I enable -threaded and +RTS -N8. Unfortunately this parallism are actually slowing down my program, probably due to being of too fine granularity. For example, with +RTS -N8 I have 47.03user 38.06system 0:21.68elapsed 392%CPU While with +RTS -N1 I have 16.57user 0.45system 0:17.02elapsed 100%CPU In .prof file I can't find whether a function fired a spark or how much 'system' time a function used. Nor can I find any names of functions/modules browsing through eventlog with ghc-events. Is there a way to find out which functions/modules are causing any parallelism at all? I am also trailing the post with the imports I used in case anyone immediately recognises parallelism by default in the package. import Control.DeepSeq import GHC.Generics (Generic, Generic1) import Text.Parsec import Data.List import Data.Vector.Unboxed(fromList, (!)) import qualified Data.Vector as V import qualified Data.Map as M import qualified Data.Set as S import Data.Char import Control.Applicative((*>),(<*)) import Test.QuickCheck.Monadic import Test.QuickCheck import Control.Monad import Text.Regex import Control.Applicative ((<$>), (<$), (<|>)) import GHC.Read (readLitChar) import Data.Char(isPrint) import Text.ParserCombinators.ReadP import Text.Show.Pretty import Data.Functor import Data.Maybe import System.Environment(getArgs) import Text.Read(readMaybe) import Text.Printf import Data.Dynamic import Debug.Trace import Data.Ratio import qualified Data.DList as D import Control.Monad.Trans.Writer.Strict import Control.Monad.Trans.Class import Data.Typeable(Typeable) import qualified Data.HashMap.Lazy as H Best, ducis

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Re: [Haskell-cafe] trace output statements
by Ian Denhardt 27 Dec '18

27 Dec '18

(Adding the list back to Cc; you forgot to hit reply all) Quoting Damien Mattei (2018-12-25 16:57:04) > i get in trouble understanding what fmap was doing, fmap (for IO) just applies a function to the result of the action, so: fmap f action is equivalent to: do result <- action return (f result) > and why the same thing to do in main and in a function had so > different implementations... I suspect the modified version of the program has some differences that aren't strictly necessary just to factor out the relevant bits into their own definition; this *shouldn't* be major surgery. Hard for me to point out without having the two full examples handy. Quoting Damien Mattei (2018-12-25 16:57:04) > yes, i understand with your python example, it's like read on a web > page, IO are not a "cake" but IO are "a recipe for the cake"... > functions are pure in haskell, so they can not have side effects... > what put me some trouble is an answer 2 weeks ago, someone gave me > hints that lead to this solution for getDB: > getBD :: Connection -> String -> IO Float > getBD conn name = trace "Entering getBD" noBDfp > � where qry_head_BD_Sidonie = "select `N° BD` from Coordonnées where > Nom = ?" :: Query > � � � � � � � bd_rows :: IO [Only Text] > � � � � � � � bd_rows = query conn qry_head_BD_Sidonie (Only > (name::String)) > � � � � � � � noBDtxt :: IO Text > � � � � � � � noBDtxt = trace "assigning noBDtxt" (fmap (fromOnly . > Prelude.head) bd_rows) > � � � � � � � noBDstr :: IO String > � � � � � � � noBDstr = trace "assigning noBDstr" (fmap Text.unpack > noBDtxt) > � � � � � � � noBDfp :: IO Float > � � � � � � � noBDfp = fmap read noBDstr > which was code different from the code in main,i get in trouble > understanding what fmap was doing , and why the same thing to do in > main and in a function had so different implementations... > > On Tue, Dec 25, 2018 at 10:19 PM Ian Denhardt <[1]ian@zenhack.net> > wrote: > > The correct type annotation for getDB3 should be: > � � getDB3 :: Connection -> String -> IO Float > Note the IO at the end. Functions in Haskell are just pure > computation; > they can't have side effects -- so a function returning a Float > can't > possibly talk to a database. > Instead, The type `IO a` represents a description of an action to > perform.� It's still just a value -- calling getDB3 doesn't *do* > anything. You can stitch these together using do-notation or > functions > like >>=, and when the program is run the action defined by 'main' > is > performed. > --- > An analogy: you could imagine instead of IO we could give up, and > write > code that computes a program in some other (imperative) programming > language) that we then hand off to an interpreter. For example, we > could > compute a python program that counts from 1 to 99 like so: > � � printNum :: Int -> String > � � printNum n = "print('" ++ show n ++ "')\n" > � � pythonProgram = concatMap printNum [1..99] > So we've defined a variable fullProgram that is a string with the > source > code to a python program like: > � � print('1') > � � print('2') > � � print('3') > � � ... > � � print('99') > ..but we haven't actually run it. To do that we'd have to pass the > string off to the python interpreter. > This is a good way to think about what IO is -- main is like our > pythonProgram above, in that it is a description of actions to > perform, > but *evaluating* it doesn't have any side effects -- it just > computes > the description. When you run a Haskell program, this is like taking > the description defined by Main and passing it off to an > interpreter. > --- > So your definition of getDB3 is a description of actions to perform > to > get a float from the database, but your type declaration says it's a > function that computes a float (without having to perform any > "actions"). > This is a critical distinction that exists in Haskell but not most > other > languages. > Hope this helps, > -Ian > Quoting Damien Mattei (2018-12-25 15:07:35) > >� � yes i use do notation, but for example i have code that works > in main > >� � and not in a function! > >� � i print the code perheaps someone could help me: > >� � first the function, so you have the import list too: > >� � import Database.MySQL.Simple > >� � import Database.MySQL.Simple.QueryResults > >� � import Database.MySQL.Simple.Result > >� � import Database.MySQL.Simple.QueryParams > >� � import Database.MySQL.Simple.Param > >� � import Control.Monad > >� � import Data.Text as Text > >� � --import Data.Int as Int > >� � --import Data.List > >� � import Debug.Trace > >� � import Data.Maybe as Maybe > >� � -- this function will return th N°BD from Sidonie for a > given name > >� � -- note: names have been standardized between Sidonie and WDS > >� � getBD3 :: Connection -> String -> Float > >� � getBD3 conn name = do > >� � � � � � � � � � � � �� let > qry_head_BD_Sidonie = "select `N° BD` from > >� � Coordonnées where Nom = ?" :: Query > >� � � � � � � � � � � � �� (bd_rows :: > [Only Text]) <- query conn > >� � qry_head_BD_Sidonie (Only (name::String)) > >� � � � � � � � � � � � �� let noBDtxt = > fromOnly (Prelude.head bd_rows) :: > >� � Text > >� � � � � � � � � � � � �� let noBDstr = > Text.unpack noBDtxt :: String > >� � � � � � � � � � � � �� let noBDfp = > read $ noBDstr :: Float > >� � � � � � � � � � � � �� return noBDfp > >� � with this function i have this error: > >� � Prelude> :load UpdateSidonie > >� � [1 of 1] Compiling Main� � � � � � � � � > � � �� ( UpdateSidonie.hs, > >� � interpreted ) > >� � UpdateSidonie.hs:54:13: error: > >� � � � �� Couldn't match expected type �Float� > with actual type �IO > >� � Float� > >� � � � �� In a stmt of a 'do' block: > >� � � � � � � � �� (bd_rows :: [Only Text]) <- > query > >� � � � � � � � � � � � � � � � � > � � � � � � � � � � � � � � � � � > � � � � > >� � � �� conn qry_head_BD_Sidonie (Only (name :: String)) > >� � � � � � �� In the expression: > >� � � � � � � � �� do let qry_head_BD_Sidonie = > ... > >� � � � � � � � � � � �� (bd_rows :: [Only > Text]) <- query > >� � � � � � � � � � � � � � � � � > � � � � � � � � � � � � � � � � � > � � � � > >� � � � � � �� conn qry_head_BD_Sidonie (Only (name :: > String)) > >� � � � � � � � � � � �� let noBDtxt = ... > >� � � � � � � � � � � �� let noBDstr = ... > >� � � � � � � � � � � �� .... > >� � � � � � �� In an equation for �getBD3�: > >� � � � � � � � � � �� getBD3 conn name > >� � � � � � � � � � � � �� = do let > qry_head_BD_Sidonie = ... > >� � � � � � � � � � � � � � � � � > �� (bd_rows :: [Only Text]) <- query > >� � � � � � � � � � � � � � � � � > � � � � � � � � � � � � � � � � � > � � � � > >� � � � � � � � � � � � �� conn > qry_head_BD_Sidonie (Only (name :: String)) > >� � � � � � � � � � � � � � � � � > �� let noBDtxt = ... > >� � � � � � � � � � � � � � � � � > �� .... > >� � � �� | > >� � 54 |� � � � � � � � � � � �� > (bd_rows :: [Only Text]) <- query conn > >� � qry_head_BD_Sidonie (Only (name::String)) > >� � � �� |� � � � � � � � � � � � > >� � > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > ^^^ > >� � ^^^^^^^^^ > >� � Failed, no modules loaded. > >� � i do not understand the error complaining that i return an IO > >� � float,because i'm sure it's a float in noBDfp > >� � if i put the same lines of code in the main it works !!! : > >� � main :: IO () > >� � main = > >� � �� do > >� � � � �� conn <- connect defaultConnectInfo > >� � � � � � �� { connectHost = "moita", > >� � � � � � � � �� connectUser = "mattei", > >� � � � � � � � �� connectPassword = "sidonie2", > >� � � � � � � � �� connectDatabase = "sidonie" } > >� � � let qry_head_BD_Sidonie = "select `N° BD` from > Coordonnées where > >� � Nom = ?" :: Query > >� � � (bd_rows :: [Only Text]) <- query conn > qry_head_BD_Sidonie (Only > >� � (name::String)) > >� � putStr "bd_rows =" > >� � putStrLn $ show bd_rows > >� � � � �� let noBDtxt = fromOnly (Prelude.head bd_rows) > :: Text > >� � � � �� let noBDstr = Text.unpack noBDtxt :: String > >� � � � �� let noBDfp = read $ noBDstr :: Float > >� � � � �� putStr "noBDfp =" > >� � � � �� (putStrLn (show noBDfp)) > >� � � close conn > >� � it works i have output like this: > >� � *Main> main > >� � bd_rows =[Only {fromOnly = "-04.3982"}] > >� � noBDtxt ="-04.3982" > >� � noBDfp =-4.3982 > >� � noBDfp + 1 = -3.3982 > >� � i'm well getting a float in noBDfp , i even can add 1 to it > :-) ( cool > >� � haskell...) > >� � but i'm just wanting to that in the function getDB3 but it > does not > >� � compile... > >� � ?????? > >� � Damien > > > >� � On Sun, Dec 23, 2018 at 4:54 PM Tom Ellis > >� � <[1][2]tom-lists-haskell-cafe-2017@jaguarpaw.co.uk> wrote: > > > >� � � I think forgetting about monads and just using do-notation > will help > >� � � you. > >� � � On Sun, Dec 23, 2018 at 04:44:57PM +0100, Damien Mattei > wrote: > >� � � > i think learning Monads from scratch again will help me > >� � � > > >� � � > On Sun, Dec 23, 2018 at 4:11 PM Tom Ellis < > >� � � > [2][3]tom-lists-haskell-cafe-2017@jaguarpaw.co.uk> > wrote: > >� � � > > >� � � > > Yes, exactly! > >� � � > > > >� � � > > On Sun, Dec 23, 2018 at 02:08:57PM +0100, Damien > Mattei wrote: > >� � � > > > lazyness....? > >� � � > > > > >� � � > > > On Sun, Dec 23, 2018 at 8:40 AM Tom Ellis < > >� � � > > > [3][4]tom-lists-haskell-cafe-2017@jaguarpaw.co.uk> > wrote: > >� � � > > > > >� � � > > > > On Sat, Dec 22, 2018 at 09:52:18AM +0100, Damien > Mattei > >� � � wrote: > >� � � > > > > > i have inserted trace statement that output > variable > >� � � > > > > > ... i have strange behavior of output: > >� � � > > > > > >� � � > > > > Let's take a simpler example.�� Do you > understand why the > >� � � trace > >� � � > > statments > >� � � > > > > from this small program appear in the order that > they do?� > >� � � (And for > >� � � > > what > >� � � > > > > it's worth I really think you'll be better off > writing > >� � � programs using > >� � � > > do > >� � � > > > > notation). > >� � � > > > > > >� � � > > > > > >� � � > > > > % cat test.hs > >� � � > > > > import Debug.Trace > >� � � > > > > > >� � � > > > > result = > >� � � > > > >�� let a = trace "evaluating a" 2 > >� � � > > > >�� b = trace "evaluating b" 10 > >� � � > > > >�� c = trace "evaluating c" (a + > b) > >� � � > > > >�� in c > >� � � > > > > ~% ghci -e result test.hs > >� � � > > > > evaluating c > >� � � > > > > evaluating b > >� � � > > > > evaluating a > >� � � > > > > 12 > >� � � > > _______________________________________________ > >� � � > > Haskell-Cafe mailing list > >� � � > > To (un)subscribe, modify options or view archives go > to: > >� � � > > > [4][5]http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe > >� � � > > Only members subscribed via the mailman list are > allowed to > >� � � post. > >� � � > _______________________________________________ > >� � � > Haskell-Cafe mailing list > >� � � > To (un)subscribe, modify options or view archives go to: > >� � � > > [5][6]http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe > >� � � > Only members subscribed via the mailman list are allowed > to post. > >� � � _______________________________________________ > >� � � Haskell-Cafe mailing list > >� � � To (un)subscribe, modify options or view archives go to: > >� � � > [6][7]http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe > >� � � Only members subscribed via the mailman list are allowed > to post. > > > > Verweise > > > >� � 1. mailto:[8]tom-lists-haskell-cafe-2017@jaguarpaw.co.uk > >� � 2. mailto:[9]tom-lists-haskell-cafe-2017@jaguarpaw.co.uk > >� � 3. mailto:[10]tom-lists-haskell-cafe-2017@jaguarpaw.co.uk > >� � 4. > [11]http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe > >� � 5. > [12]http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe > >� � 6. > [13]http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe > > Verweise > > 1. mailto:ian@zenhack.net > 2. mailto:tom-lists-haskell-cafe-2017@jaguarpaw.co.uk > 3. mailto:tom-lists-haskell-cafe-2017@jaguarpaw.co.uk > 4. mailto:tom-lists-haskell-cafe-2017@jaguarpaw.co.uk > 5. http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe > 6. http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe > 7. http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe > 8. mailto:tom-lists-haskell-cafe-2017@jaguarpaw.co.uk > 9. mailto:tom-lists-haskell-cafe-2017@jaguarpaw.co.uk > 10. mailto:tom-lists-haskell-cafe-2017@jaguarpaw.co.uk > 11. http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe > 12. http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe > 13. http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe

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Poor performance when using hsc2hs to cross-compile
by Vanessa McHale 26 Dec '18

26 Dec '18

Hi all, I've been trying to cross-compile X11 for ARM. Unfortunately, the build runs in the preprocessor phase for a very very long time when preprocessing Graphics/X11/Types.hsc Upon passing -v to hsc2hs I saw many steps like checking XK_abrevebelowdot `GreaterOrEqual` Unsigned 17039360 executing: /usr/bin/arm-linux-gnueabihf-gcc -c /home/vanessa/git-builds/junk/X11-1.9/dist-newstyle/build/arm-linux/ghc-8.6.3/X11-1.9/build/Graphics/X11/ExtraTypes/XorgDefault_hsc_test37988.c -o /home/vanessa/git-builds/junk/X11-1.9/dist-newstyle/build/arm-linux/ghc-8.6.3/X11-1.9/build/Graphics/X11/ExtraTypes/XorgDefault_hsc_test37988.o -marm -fno-stack-protector '-fuse-ld=gold' -Wl,-z,noexecstack '-D__GLASGOW_HASKELL__=806' '-Dlinux_BUILD_OS=1' '-Dx86_64_BUILD_ARCH=1' '-Dlinux_HOST_OS=1' '-Darm_HOST_ARCH=1' -Iinclude -I/home/vanessa/git-builds/junk/X11-1.9/dist-newstyle/build/arm-linux/ghc-8.6.3/X11-1.9/build/include -I/home/vanessa/git-builds/junk/X11-1.9/dist-newstyle/build/arm-linux/ghc-8.6.3/X11-1.9/build/autogen -I/home/vanessa/git-builds/junk/X11-1.9/dist-newstyle/build/arm-linux/ghc-8.6.3/X11-1.9/build/global-autogen -include /home/vanessa/git-builds/junk/X11-1.9/dist-newstyle/build/arm-linux/ghc-8.6.3/X11-1.9/build/autogen/cabal_macros.h -I/usr/local/lib/arm-linux-gnueabihf-ghc-8.6.3/base-4.12.0.0/include -I/usr/local/lib/arm-linux-gnueabihf-ghc-8.6.3/integer-gmp-1.0.2.0/include -I/usr/local/lib/arm-linux-gnueabihf-ghc-8.6.3/include result: False which I assume are necessary or at least progressing... Is there any way to speed this up? Is it a bug of some sort in hsc2hs or X11? Is there any hope in reporting upstream to the appropriate project (and what is the appropriate project in this case?)? Cheers, Vanessa

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ZuriHac 2019 registration now open
by Jasper Van der Jeugt 26 Dec '18

26 Dec '18

Hello Friends of Haskell, We are happy to announce that registration for ZuriHac 2019 is now open. Participation is free but limited to 450 attendees. You can register at: https://zfoh.ch/zurihac2019/#registration This year, we've taken dogfooding a step further and rolled our own open source registration system in Haskell, so please let me know if you experience any issues. ZuriHac 2019 will take place from Friday the 14th to Sunday the 16th of June 2019. It will be hosted at the Hochschule Rapperswil on the shores of beautiful Lake Zurich. This will mark the 8th anniversary of ZuriHac since our beginnings in 2010. The Zurich Haskell Hackathon is a free, international, grassroots, and collaborative coding festival. Our goal is to connect Haskellers, expand the community, learn things from each other, and to work on Haskell libraries, tools, and infrastructure. This year, we will enjoy keynotes from: - Simon Peyton Jones - Susan Potter - Richard Eisenberg - Ryan Trinkle More keynote speakers will be announced. The event is open to any experience level, from beginners to gurus. We want to make a special effort to ensure that the event is welcoming and accessible to people completely new to Haskell. That is why we are super excited that, Julie Moronuki, co-author of Haskell Programming from first principles [1] and Joy of Haskell [2], has kindly agreed to teach a beginners course in one of the classrooms we have available. Additionally, there will be mentors that you can approach during the whole event with any Haskell-related questions. This is a great opportunity to meet your fellow Haskellers in real life, find new contributors for your project, improve existing libraries and tools or even start new ones! You can find all of this information and more on our website: https://zfoh.ch/zurihac2019 We would also like to thank our sponsors Digital Asset [3], DFINITY [4] and HSR [5] for their strong commitment to the Haskell community and for supporting this great event! Looking forward to seeing you there, The Zurich Friends of Haskell association. [1]: https://www.goodreads.com/book/show/25587599-haskell-programming [2]: https://joyofhaskell.com/ [3]: https://digitalasset.com/careers.html [4]: https://dfinity.org/jobs [5]: https://www.hsr.ch/

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Taking over maintainership of syb
by Sergey Vinokurov 25 Dec '18

25 Dec '18

I'd like to become maintainer of the syb package (http://hackage.haskell.org/package/syb) The current maintainer, José Pedro Magalhães, would like to step down and is looking for anyone interested in picking up the package (https://github.com/dreixel/syb/pull/19) Best regards, Sergey

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trace output statements
by Damien Mattei 25 Dec '18

25 Dec '18

i have this function: -- this function will return th N°BD from Sidonie for a given name -- note: names have been standardized between Sidonie and WDS getBD :: Connection -> String -> IO Float getBD conn name = trace "Entering getBD" noBDfp where qry_head = "select `N° BD` from Coordonnées where Nom = ?" :: Query bd_rows :: IO [Only Text] bd_rows = query conn qry_head (Only (name::String)) -- noBDtxt :: [Text] -- noBDtxt = fromOnly (Prelude.head bd_rows) -- noBDtxt :: IO [Text] -- lg = fmap Prelude.length bd_rows -- lg2 = fmap show lg noBDtxt :: IO Text -- noBDtxt = trace "lg " (fmap (fromOnly . Prelude.head) bd_rows) noBDtxt = trace "assigning noBDtxt" (fmap (fromOnly . Prelude.head) bd_rows) -- noBDstr :: String -- noBDstr = Text.unpack noBDtxt noBDstr :: IO String noBDstr = trace "assigning noBDstr" (fmap Text.unpack noBDtxt) -- noBDfp = read $ noBDstr :: Float noBDfp :: IO Float noBDfp = fmap read noBDstr call by : let lstBD = Prelude.map (\elem -> getBD conn (Text.unpack (fst elem))) rows it works ok, in fact at some point it fails due to NULL sql value not again handle correctly , i have inserted trace statement that output variable, i understand it's not really good becaus it breaks the purity of haskell function, perheaps for this reason i have strange behavior of output: ... Entering getBD assigning noBDstr assigning noBDtxt Entering getBD assigning noBDstr assigning noBDtxt Entering getBD assigning noBDstr assigning noBDtxt *** Exception: UnexpectedNull {errSQLType = "VarString", errHaskellType = "Text", errFieldName = "N\194\176 BD", errMessage = "unexpected null in table Coordonn\195\169es of database sidonie"} *Main> you will notice noBDstr seems to be assigned before noBDtxt, but in the code i have the statements in this order: noBDtxt = trace "assigning noBDtxt" (fmap (fromOnly . Prelude.head) bd_rows) noBDstr :: IO String noBDstr = trace "assigning noBDstr" (fmap Text.unpack noBDtxt) i just want to understand wht's happening, this is not critical for code as it works... any idea? Damien

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Re: [Haskell-cafe] Places to write and publish projects that 'explain ideas'
by Doug McIlroy 25 Dec '18

25 Dec '18

The project (or an appropriate-sized coherent piece thereof) seems like a good fit for the "programming pearls" department in the Journal of Functional Programming Doug McIlroy

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Re: [Haskell-cafe] Places to write and publish projects that "explain ideas"?
by Siddharth Bhat 25 Dec '18

25 Dec '18

Regarding (1), as far as I'm aware, the requirements are flexible, but the general requirement is "published a paper at a good venue, either journal or conference". This implementation was a hobby project of mine, but I was hoping to be able to justify spending more time on it by finding a venue to publish it at. As for (2), it's mostly expository. The techniques that I am interesting in showing off have no known "simple" implementations as far as I'm aware -- scalar evolution, polyhedral compilation, some kinds of inter-procedural analyses, SSA, etc. do not have simple implementations. Indeed, the goal is to show how to write *optmising* compilers. Most compilers books teach one how to write *a compiler, *while there's a second course usually on compiler optimisation. I don't know of readable, clean implementations of, say, the SSA construction algorithm, or the scalar evolution analysis. Regarding nanopass: I think it makes a lot of sense as a philosophy as a way to architect compilers. However, there are a lot of nice haskell-isms to write compilers which are scattered throughout the literature, as far as I can tell: Hoopl, trees that grow, much of Matt might's work on abstracting abstract interpreters, Scrap-your-boilerplate style techniques, equality saturation, etc. which are all fantastic, but I've never seen them under the same umbrella. So that's a sketch of the general story I want to tell :) Thanks. ~Siddharth On Tue, Dec 25, 2018 at 7:30 PM Richard O'Keefe <raoknz(a)gmail.com> wrote: > > Question 1: what does your department require? The first person to > consult > is your supervisor. Helping students figure out where to publish is > definitely > part of a supervisor's job (speaking as a former supervisor of PhD > students). > > Question 2: what is the TOPIC of your publication? Since you are merely > (!) > demonstrating known techniques on a toy language, does it really count as > work on compilers? Is it software engineering? Is it computer science > education? Is the aim to develop something more maintainable? What is the > quality metric by which your work should be judged? > > Observation: if you haven't already read the "Nanopass" paper, > https://www.cs.indiana.edu/~dyb/pubs/nano-jfp.pdf , > you should do so now. http://nanopass.org/ is the associated web site. > There is also a mailing list, > https://groups.google.com/forum/#!forum/nanopass-framework > I think your aims are sufficiently close to theirs for you to have > interesting things to say to each other, despite you using Haskell and > them having used Scheme. > > >

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Places to write and publish projects that "explain ideas"?
by Siddharth Bhat 25 Dec '18

25 Dec '18

Hello all, I have somewhat of an unorthodox problem. I've been writing on and off, a series on implementing compilers "beautifully" in haskell, called tiny-optimising-compiler <http://github.com/bollu/tiny-optimising-compiler>. They're literate haskell files, with the aim of explaining the really elegant ideas that exist in compilers literature - data flow analysis, abstract interpretation, SSA, continuations, scalar evolution, and some more slightly out-there / research-y things, like polyhedral compilation, equality saturation. However, I'm also a research student at my university, and am expected to publish before I graduate. I was looking for possible places to publish a project such as this, whose selling point would be "explains things elegantly, and possibly rewords standard things to nice looking haskell". Are there places where one could conceivably publish about such a project? If not, I forsee myself not being able to finish this project for a while longer, and that would make me sad. Thanks, and a merry christmas to all, ~Siddharth

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