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ANN: iyql - interactive yql
by Diego Souza 09 Sep '10

09 Sep '10

Hi All, I'm pleased to announce iyql, an interactive CLI for YQL [ http://developer.yahoo.com/yql/console] This version provides the first release, which allows you perform all queries supported by YQL [with the sole exception of parenthesis in WHERE clause]. Among other things, completion and history are implemented [=haskeline] along with support for queries that requires OAuth authentication. Plans for next releases: * Implement a decent error handling: currently any unexpected exception aborts the program; * Support parenthesis in WHERE clause; * More local functions; Please let me know about any issues or suggestions! Regards, -- ~dsouza yahoo!im: paravinicius gpg key fingerprint: 71B8 CE21 3A6E F894 5B1B 9ECE F88E 067F E891 651E gpg pub key: http://bitforest.org/~dsouza/pub/gpg-pubkey.txt<http://bitforest.org/%7Edsouza/pub/gpg-pubkey.txt> authorized_keys: http://bitforest.org/~dsouza/pub/authorized_keys.txt<http://bitforest.org/%7Edsouza/pub/authorized_keys.txt>

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Re: [Haskell-cafe] Re: Re: [Haskell] ANNOUNCE: reference 0.1
by Maciej Piechotka 08 Sep '10

08 Sep '10

On Wed, 2010-09-08 at 09:53 +0200, Alberto G. Corona wrote: > Ah, ok. I though that your intention was to restrict the class > definition for the IO monad . Goood. > > > Maybe in the long term, it make sense to include this type class in > some monad related package such is mtl, since references are part of > many user monads. I think also that some default instances can be > defined for transformed monads. > Yes - they can. In fact: instance (MonadTrans t, Monad (t m), Reference r m) => Reference r (t m) where newRef = lift . newRef readRef = lift . readRef writeRef r = lift . writeRef r instance (MonadIO m, Reference r IO) => Reference r m where newRef = liftIO . newRef readRef = liftIO . readRef writeRef r = liftIO . writeRef r > > It is pleasant for me to read and write something like > > > x <- readRef rx > > > rather than > > > x<- readMyMonadRef sx > > > Such generalizatiopns may be also good for extracting more common > patterns among different monads. Actually the primary need was to create mutable single-linked list for iteratee-parsec. I didn't wanted to restrict myself to ST or IO so I choose to add class for them. Regards

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ANNOUNCE: grammar-combinators 0.1 (initial release): A parsing library of context-free grammar combinators
by Dominique Devriese 08 Sep '10

08 Sep '10

The grammar-combinators library is a parsing library employing a novel grammar representation with explicit recursion. The library features much of the power of a parser generator like Happy or ANTLR, but with the library approach and most of the benefits of a parser combinator library. Grammars and grammar algorithms are defined in a functional style. The library currently has the following features: * Grammar specified completely in Haskell using an elegant syntax * Grammar algorithms implemented in a functional style (no fresh identifiers), with elegant and meaningful types. * Multi-backend: use the same grammar with a Packrat, Parsec or UUParse parser * Grammar transformations: use left-recursive grammars directly thanks to a powerful grammar transformation library, featuring the left-corner left-recursion removal transform, a uniform version of the classic Paull left-recursion removal, and various smaller transformations (dead-branch removal, dead non-terminal removal, consecutive epsilon combination, selective unfolding etc.). * Grammar utility functions: printing of grammars, FIRST-set calculation, reachability analysis of non-terminals, etc. * Compile-time transformations (using Template Haskell), given a suitable definition of the grammar. This is currently limited to a certain set of transformations. The library is currently not intended for mainstream use. Its API is relatively stable, but performance needs to be looked at further. We are submitting a paper about the ideas behind this library to PADL 2011. A draft is linked on the project's website. More information: * Project website: http://projects.haskell.org/grammar-combinators/ * Tutorial: http://projects.haskell.org/grammar-combinators/tutorial.html * Hackage: http://hackage.haskell.org/package/grammar-combinators All comments welcome! Dominique PS. The documentation on hackage currently doesn't build because of (seemingly) a Hackage dependency problem during the build [1]. Compiling and generating the documentation locally should work fine. A version of the docs is available on the project's webpage as a temporary replacement [2]. Footnotes: [1] http://www.haskell.org/pipermail/libraries/2010-September/014168.html [2] http://projects.haskell.org/grammar-combinators/docs/index.html

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ANNOUNCE: reference 0.1
by Maciej Piechotka 07 Sep '10

07 Sep '10

Reference is class which generalizes references and monads they exists in. It means that IORef, STRef and others can be accessed by common interface. Currently it is of form: class Reference r m where 1. There was a proposal to rename the class to MonadRef or MonadReference. IMHO it would imply m -> r functional dependency and therefore disallow the instances for both MVar IO and IORef IO 2. Should the functional dependencies or type famillies be introduced? Personally I don't think so as I would like to allow all of the following: - IORef IO - MVar IO - IORef (ContT IO) - MVar (ContT IO) Any feedback mostly welcome. Regards PS. Darcs repository will be available soon

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TLDI 2011: 2nd Call For Papers
by Stephanie Weirich 07 Sep '10

07 Sep '10

TLDI 2011 2nd CALL FOR PAPERS The Sixth ACM SIGPLAN Workshop on Types in Language Design and Implementation Austin, Texas, USA Tuesday, January 25, 2011 (Co-located with POPL 2011) http://www.mpi-sws.org/~dreyer/tldi2011/ Submission Deadline: October 11, 2010 The role of types and proofs in all aspects of language design, compiler construction, and software development has expanded greatly in recent years. Type systems, type-based analyses and type-theoretic deductive systems have been central to advances in compilation techniques for modern programming languages, verification of safety and security properties of programs, program transformation and optimization, and many other areas. The ACM SIGPLAN Workshop on Types in Language Design and Implementation brings researchers together to share new ideas and results concerning all aspects of types and programming, and is now an annual event. TLDI 2011 is the sixth workshop in the series and will be co-located with POPL in Austin, Texas in January 2011. Submissions for TLDI 2011 are invited on all interactions of types with language design, implementation, and programming methodology. This includes both practical applications and theoretical aspects. TLDI 2011 specifically encourages papers from a broad field of programming language and compiler researchers, including those working on object-oriented or dynamic languages, systems programming, mobile-code or security, as well as traditional fully-static type systems. Topics of interest include: * Typed intermediate languages and type-directed compilation * Type-based language support for safety and security * Types for interoperability * Type systems for system programming languages * Type-based program analysis, transformation, and optimization * Dependent types and type-based proof assistants * Types for security protocols, concurrency, and distributed computing * Type inference and type reconstruction * Type-based specifications of data structures and program invariants * Type-based memory management * Proof-carrying code and certifying compilation * Types and objects This is not meant to be an exhaustive list; papers on novel utilizations of type information are welcome. Authors concerned about the suitability of a topic are encouraged to inquire via electronic mail to the program chair prior to submission. Submission Guidelines: Authors should submit a full paper of no more than 12 pages (including bibliography and appendices) by Monday, October 11, 2010. The submission deadline and length limitations are firm. Submissions that do not meet these guidelines will not be considered. All submissions should be in standard ACM SIGPLAN conference format: two columns, nine-point font on a ten-point baseline. Detailed formatting guidelines are available on the SIGPLAN Author Information page, along with a LaTeX class file and template. Papers must be submitted electronically via the workshop website (http://www.mpi-sws.org/~dreyer/tldi2011/) in Adobe Portable Document Format (PDF) and must be formatted for US Letter size (8.5"x11") paper. Authors for whom this is a hardship should contact the program chair before the deadline. Submitted papers must adhere to the SIGPLAN Republication Policy. Submissions should contain original research not published or submitted for publication elsewhere. Publication: As in previous years, accepted papers will be published by the ACM and appear in the ACM digital library. A printed proceedings will be available at the workshop. Important Dates: - Submission deadline: October 11, 2010 (Monday), 21:00 Samoa-Apia Time - Notification: November 8, 2010 (Monday) - Final versions due: November 22, 2010 (Monday) - Workshop: January 25, 2011 (Tuesday) General Chair: Stephanie Weirich University of Pennsylvania sweirich at cis dot upenn dot edu Program Chair: Derek Dreyer Max Planck Institute for Software Systems (MPI-SWS) dreyer at mpi-sws dot org Program Committee: Thorsten Altenkirch (University of Nottingham) Fritz Henglein (University of Copenhagen) Michael Hicks (University of Maryland, College Park) Limin Jia (Carnegie Mellon University) Mark Jones (Portland State University) Neel Krishnaswami (Microsoft Research, Cambridge) Paul-André Melliès (CNRS & Université Paris Diderot) Aleks Nanevski (IMDEA Software, Madrid) Benjamin Pierce (University of Pennsylvania) Tachio Terauchi (Tohoku University) Sam Tobin-Hochstadt (Northeastern University) Steering Committee: Amal Ahmed (Indiana University) Nick Benton (Microsoft Research, Cambridge) Derek Dreyer (MPI-SWS) Robert Harper (Carnegie Mellon University, chair) Andrew Kennedy (Microsoft Research, Cambridge) Francois Pottier (INRIA Rocquencourt) Zhong Shao (Yale University) Stephanie Weirich (University of Pennsylvania)

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ANN: hledger 0.12.1
by Simon Michael 06 Sep '10

06 Sep '10

I'm pleased to announce hledger 0.12.1, with a new web interface and bugfixes. Thanks to Ben Boeckel and David Patrick for their help this time around. Installation docs, linux/mac/windows binaries and more are at http://hledger.org and http://hackage.haskell.org/package/ hledger . Release notes: 2010/9/6 hledger 0.12.1 * web: new, better web ui; accounts are now a permanent sidebar; add form uses auto-completing combo fields * installing: fix a build error with parsec 3 (#22) * installing: require exactly matching hledger-lib version for more robust builds * installing: explicit data-object dependency to ensure hledger and hledger-lib use the same time version * installing: explicit hamlet dependency for more robust building * installing: build threaded and with warnings * installing: drop -fweb610 flag * installing: add gtk2hs-buildtools dependency needed to build with -fchart * installing: require cabal 1.6 or greater * add -D/--daily flag * register: with --depth, clip account names or aggregate postings rather than excluding them * fix !include with deeply nested directories (#21) * fix obscured date parse errors with parsec 3 * handle unicode better in errors * fix a ghc 6.12.3 error when running interpreted Stats: 50 days and 90 commits since last release, now at 5741 lines of code with 136 tests and 41% unit test coverage. Goals for the next release are: 1. implement a plugin mechanism, probably by searching for hledger-* named binaries in $PATH at startup and handing over control. This should make packaging easier and more scalable. 2. move web/vty/chart features into their own packages. 3. developer docs 4. a public project ledger tracking expenses/income/resources Problem reports and all help are welcome; additional bugfix releases will appear on hackage if needed. Best, -Simon

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Re: ANNOUNCE: countable-0.1
by Maciej Piechotka 06 Sep '10

06 Sep '10

On Mon, 2010-09-06 at 03:54 -0700, Ashley Yakeley wrote: > countable: Countable, Searchable, Finite, Empty classes. > > class Countable, for countable types > class AtLeastOneCountable, for countable types that have at least one > value > class InfiniteCountable, for infinite countable types > class Searchable, for types that can be searched over > class Finite, for finite types > class Empty, for empty types > data Nothing, an empty type > > Also includes these orphan instances: > > instance (Searchable a,Eq b) => Eq (a -> b) > instance (Finite a) => Foldable ((->) a) > instance (Finite a) => Traversable ((->) a) > instance (Show a,Finite a,Show b) => Show (a -> b) > > It turns out Searchable includes some infinite types. Specifically, > countable implements this: > > instance (Countable c,Searchable s) => Searchable (c -> s) > > using the algorithm described here: > > http://math.andrej.com/2007/09/28/seemingly-impossible-functional-programs/ > > I would welcome improvements. > > http://hackage.haskell.org/package/countable-0.1 > cabal install countable > darcs get http://code.haskell.org/countable/ > > See also this thread: > http://thread.gmane.org/gmane.comp.lang.haskell.cafe/73275 > Hmm. 1. Code formatting is very C#-like. At least for me it is hard to read the code that way (it IS matter of preference however) 2. countMaybeNext seems to need documentation. If I understand it correctly: countMaybeNext Nothing = 'minimalValue' countMaybeNext (Just x) = x + 1 Wouldn't be split it to: countNext :: a -> Maybe a initial :: Maybe a 3. Regards

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ANNOUNCE: LibZip 0.1, BSD library to read and write zip archives
by Sergey Astanin 06 Sep '10

06 Sep '10

Dear Haskellers, I am glad to announce that LibZip, a major remake of Haskell bindings to libzip library, is now available [1]. As far as I know, LibZip the only non-GPL library for Haskell to manipulate zip archives (zip-archive library is GPLv2, LibZip is BSD). LibZip is also reasonably fast with large on-disk archives (more about it in the blog post, see a link below [2]). New LibZip covers almost all features of the corresponding C library: * creating, reading, updating, renaming, and deleting files in zip archives * reading and writing file and archive comments * support of various data sources: from a buffer, from a file, from another archive and from a pure function With respect to the old LibZip 0.0, there is a new monadic interface [3], more tests, examples and documentation. Users of LibZip 0.0 may still use the old API by importing Codec.Archive.LibZip.LegacyZeroZero instead of Codec.Archive.LibZip. However, the old API is deprecated and will not be supported in the future. Links: [1] Hackage page: http://hackage.haskell.org/package/LibZip [2] Blog post: http://nix-tips.blogspot.com/2010/09/libzip-01-read-and-write-zip-archives.… [3] Documentation: http://sovety.org.ru/doc/LibZip/Codec-Archive-LibZip.html Best regards, Sergey Astanin

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AngloHaskell 2010 - Final Reminder + Wi-Fi Sign-Up
by Derek Wright 06 Sep '10

06 Sep '10

AngloHaskell 2010 is this week! AngloHaskell 2010 - 5th Annual Haskell Meeting in England Friday September 10th and Saturday September 11th, 2010 Microsoft Research, Cambridge, UK http://www.haskell.org/haskellwiki/AngloHaskell/2010 AngloHaskell is a free gathering of all people Haskell-related from beginners to seasoned hackers, both academic and industrial. AngloHaskell 2010 is generously hosted by Microsoft Research. As a result no charge is made for attending or speaking. Friday will be a day of talks and discussion at MSR followed by a more informal day of activities on Saturday somewhere else in Cambridge. AngloHaskell welcomes talks on all Haskell related subjects. From short comments (Functional Grit) to full presentations, all are welcome. Please add your name and the title of your talk to the wiki page (or email me and I will add it for you). If you want to attend please add your name to the wiki page, or let me know by email. Even if you can't attend you can add you name to the "Not this year, but hopefully next!" section. Wi-Fi accounts (at Microsoft Research on Friday) are available on request. The sign-up deadline is Wednesday 8th September so please sign-up on the wiki page or email me (with Full Name, Institution, Country of Residence and Email Address). Organisational discussions are on held on the #anglohaskell channel on the Freenode IRC network, feel free to drop in with questions or comments.

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Re: ANNOUNCE: countable-1.0
by Nicolas Pouillard 06 Sep '10

06 Sep '10

On Mon, 06 Sep 2010 03:46:18 -0700, Ashley Yakeley <ashley(a)semantic.org> wrote: > countable: Countable, Searchable, Finite, Empty classes. > > class Countable, for countable types > class AtLeastOneCountable, for countable types that have at least one > value > class InfiniteCountable, for infinite countable types > class Searchable, for types that can be searched over > class Finite, for finite types > class Empty, for empty types > data Nothing, an empty type > > Also includes these orphan instances: > > instance (Searchable a,Eq b) => Eq (a -> b) > instance (Finite a) => Foldable ((->) a) > instance (Finite a) => Traversable ((->) a) > instance (Show a,Finite a,Show b) => Show (a -> b) Could you put these instances in a dedicated module? In the same vein I would like to have a newtype wrapper over functions were intention is to be used extensionally. Nice package BTW! -- Nicolas Pouillard http://nicolaspouillard.fr

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