- Haskell-Cafe - Haskell.org

ANN: hledger 0.20
by Simon Michael 02 May '13

02 May '13

I'm pleased to announce hledger and hledger-web 0.20! hledger is a command-line tool and haskell library for tracking financial transactions, which are stored in a human-readable plain text format. In addition to reporting, it can also help you record new transactions, or convert CSV data from your bank. Add-on packages include hledger-web (providing a web interface), hledger-irr and hledger-interest. hledger is inspired by and compatible with John Wiegley's Ledger. For more, see http://hledger.org . Install it: # cabal update; cabal install hledger-web For more installation help, see http://hledger.org/MANUAL.html#installing . Or, sponsor a ready-to-run binary for your platform: http://hledger.org/DOWNLOAD.html . Release notes (http://hledger.org/NEWS.html#hledger-0.20) **Bugs fixed:** * balance: a 0.19 regression which showed wrong total balance with `--flat` has been fixed (#94) * register: when `--date2` is used, the register is now sorted by the secondary date * web: some missing static & template files have been added to the package, fixing cabal-dev and hackage builds (#97, #98) * web: some hardcoded static urls have been fixed * Dependencies and code have been updated to support the latest libraries and GHC versions. For now, hledger requires GHC 7.2+ and hledger-web requires GHC 7.4+. **Journal reading:** - DOS-style line-endings are now also supported in journal and rules files. - `!` is now accepted in the status field as well as `*`, like ledger - The *actual date* and *effective date* terminology has changed to *primary date* and *secondary date*. Use `--date2` to select the secondary date for reports. (`--aux-date` or `--effective` are also accepted for ledger and backwards compatibility). - Per-posting dates are supported, using hledger tags or ledger's posting date syntax - Comment and tag handling has been improved **CSV reading:** - CSV conversion rules have a simpler, more flexible [syntax](MANUAL.html#csv-files). Existing rules files will need to be updated manually: - the filename is now `FILE.csv.rules` instead of `FILE.rules` - `FIELD-field N` is now `FIELD %N+1` (or set them all at once with a `fields` rule) - `base-currency` is now `currency` - `base-account` is now `account1` - account-assigning rules: add `if` before the list of regexps, add indented `account2 ` before the account name - parenthesised amounts are parsed as negative **Querying:** - Use `code:` to match the transaction code (check number) field - Use `amt:` followed by `<`, `=` or `>` and a number N to match amounts by magnitude. Eg `amt:<0` or `amt:=100`. This works only with single-commodity amounts (multi-commodity amounts are always matched). - `tag:` can now match (exact, case sensitive) tag values. Eg `tag:TAG=REGEXP`. **add comand:** - Transaction codes and comments (which may contain tags) can now be entered, following a date or amount respectively. (#45) - The current entry may be restarted by entering `<` at any prompt. (#47) - Entries are displayed and confirmed before they are written to the journal. - Default values may be specified for the first entry by providing them as command line arguments. - Miscellaneous UI cleanups **register command:** - The `--related`/`-r` flag shows the other postings in each transaction, like ledger. - The `--width`/`-w` option increases or sets the output width. **web command:** - The web command now also starts a browser, and auto-exits when unused, by default ("local ui mode"). With `--server`, it keeps running and logs requests to the console ("server mode"). - Bootstrap is now used for styling and layout - A favicon is served - The search field is wider - yesod devel is now supported; it uses `$LEDGER_FILE` or `~/.hledger.journal` - the `blaze_html_0_5` build flag has been reversed and renamed to `blaze_html_0_4` **Add-ons:** - The hledger-interest and hledger-irr commands have been released/updated. - hledger-chart and hledger-vty remain unmaintained and deprecated. **Documentation and infrastructure:** - The hledger docs and website have been reorganised and updated - Manuals for past releases are provided as well as the latest dev version - hledger has moved from darcs and darcs hub to git and github (!) - The bug tracker has moved from google code to github - Feature requests and project planning are now managed on trello - A build bot builds against multiple GHC versions on each commit Release contributors: - Sascha Welter commissioned register enhancements (--related and --width) - David Patrick contributed a bounty for add enhancements - Joachim Breitner added support for ! in status field - Xinruo Sun provided hledger-web build fixes - Peter Simons provided hledger-web build fixes, and a build bot - Marko Kocić provided hledger-web fixes

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What is the process for GSOC?
by Dominic Steinitz 01 May '13

01 May '13

How is it decided which Haskell projects get chosen? Do we discuss them here and take a collective view? Thanks, Dominic. PS I should point out I have an interest in the proposal to port charts to use diagrams (http://www.google-melange.com/gsoc/proposal/review/google/gsoc2013/jbracker…) i.e. I'd really like this as a user.

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Re: [Haskell-cafe] Space leak in hexpat-0.20.3/List-0.5.1
by oleg＠okmij.org 01 May '13

01 May '13

Wren Thornton wrote: > So I'm processing a large XML file which is a database of about 170k > entries, each of which is a reasonable enough size on its own, and I only > need streaming access to the database (basically printing out summary data > for each entry). Excellent, sounds like a job for SAX. Indeed a good job for a SAX-like parser. XMLIter is exactly such parser, and it generates event stream quite like that of Expat. Also you application is somewhat similar to the following http://okmij.org/ftp/Haskell/Iteratee/XMLookup.hs So, it superficially seems XMLIter should be up for the task. Can you explain which elements your are counting? BTW, xml_enum already checks for the well-formedness of XML (including the start-end tag balance, and many more criteria). One can assume that the XMLStream corresponds to the well-formed document and only count the desired start tags (or end tags, for that matter).

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GSoC - A Cabal Project
by Martin Ruderer 30 Apr '13

30 Apr '13

Hi, I am proposing a GSoC project on Cabal. It aims to open up the dependency solver for debugging purposes. The details are here: https://gist.github.com/mr-/7995081f89cff38e9443 I would really like to hear what you think about it. Best regards, Martin

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ghc-7 -fPIC error
by Christopher Howard 30 Apr '13

30 Apr '13

Hey guys, this probably isn't the official GHC mailing list, but I've been trying to build and install a new GHC on an old RHEL5 system, as mentioned in my previous Cafe thread. I was able to make some good headway: I installed a ghc-6.8 binary, and then used that to build ghc-6.10 source, and then used that to build ghc-6.12 source. The idea is to keep going until I get to ghc-7.6. However, when I get to 7.0, my builds all eventually die with this error: quote: -------- /usr/bin/ld: rts/dist/build/RtsStartup.dyn_o: relocation R_X86_64_PC32 against `StgRun' can not be used when making a shared object; recompile with -fPIC /usr/bin/ld: final link failed: Bad value collect2: ld returned 1 exit status -------- After this failed the first time, I tried adding -fPIC to SRC_HC_OPTS, GhcStage1HcOpts, and so forth in build.mk. But ultimately I get the same error. I tried skipping a version and building ghc-7.2 instead, but the same error pops up. -- frigidcode.com

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Haskell compilation errors break the complexity encapsulation on DSLs
by Alberto G. Corona 30 Apr '13

30 Apr '13

Hi I ever was worried about the barrier that the complexity of the Haskell errors impose to users of DSLs. Many DSLs look so simple that even someone without knowledge of Haskell can make use of them for some domains. However when the program is compiled then al the monsters of the deep appear in the surface: polymorphisms, undefined instances, type errors reported in a line produced by a type assumption in another, etc. This is a problem for an industrial use of Haskell in the large scale. For obvious reasons. I would like to know 1) which techniques are used to minimize the problem 2) To suggest some kind of extension that would allow for example to add extra information to the error messages by the library developer.. For example, in http://hackage.haskell.org/packages/archive/control-monad-exception/0.10.3.… There is a nice documentation about two kind of errors that are frequent when using that library: *A type error of the form: * * No instance for (UncaughtException MyException) arising from a use of `g' at examples/docatch.hs:21:32-35 Possible fix: add an instance declaration for (UncaughtException MyException) In the expression: g ()* *is the type checker saying: * *"hey, you are trying to run a computation which throws a MyExceptionwithout handling it, and I won't let you" * *Either handle it or declare MyException as an UncaughtException<http://hackage.haskell.org/packages/archive/control-monad-exception/0.10.3.…>. * The question: Is it possible to develop a GHC extension that attach (or prepend) such an explanation to the ghc error? Or any other alternative that carry out the same functionality. -- Alberto.

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Packages in distro mentioned on hackage?
by Magnus Therning 30 Apr '13

30 Apr '13

I've noticed that some packages have a mention of distributions that include it, and which version. How does a distro get to be added like that? /M -- Magnus Therning OpenPGP: 0xAB4DFBA4 email: magnus(a)therning.org jabber: magnus(a)therning.org twitter: magthe http://therning.org/magnus

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Re: [Haskell-cafe] Markdown extension for Haddock as a GSoC project
by Mateusz Kowalczyk 30 Apr '13

30 Apr '13

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 28/04/13 00:08, Joe Nash wrote: > Managed not to send to all: > > I think the reason markdown was the original suggestion was due to > the fact it is a very widespread and popular syntax, and as Johan > commented in the original thread, has to an extent "won". Having a > consistent, standard documentation syntax for Haskell is of course > important, but this project also seeks to standardise the syntax > beyond Haskell. I don't think standardising it beyond Haskell is the goal at all. I think that coming up with Markdown that doesn't repeat the mistakes of all the flavours out there is quite difficult in itself, but coming up with such Markdown AND making it making it flexible enough to be of any use with Haddock as is? I think it might be a little out of scope. Extending Haddock itself and providing a writer (and a new reader) for Pandoc will let you write Markdown if you please and then convert it to (and from) many of the formats supported by Pandoc. > It may be hedging our bets, as a lot could change and markdown > could suddenly fall from fame, but I believe the large variety of > opposing markup languages are failing to gain traction in > comparison and it is indeed a safe bet. While I don't think it will fall from fame overnight, it would be a shame to restrict people to just using Markdown because that's how all the extensions were implemented. > > If the flexibility of having it pandoc compatible is a desired > feature, can this not be achieved through implementing markdown for > haddock as well? Depending on what haddock specific features were > required to be added to the superset, it may require only minimal > changes to an existing markdown reader/writer in pandoc already. It can, but the restriction comment applies here as well. - -- Mateusz K. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (GNU/Linux) iQIcBAEBAgAGBQJRfPllAAoJEM1mucMq2pqXaKAP/20x2549NvfJgib9oitm1Qn8 CCpGRHdSw4xlIh0pHUE1MKyiJrGGgchuUErN2CJBOKXPhn1fgCWFKJyfOhcPbyr7 2Tpb9t++9G9u0JtIb6/UQpgy6RDXQAqOUs78KxRx3DCb3rYuT5TNpr5ynS58T1+9 7eGQXeUQwhCkKZH6EuIF0qTwxPTsMOAT66oRVnaZJFl2+rOBcw8ZmxMsHnk3bX9t VAR+ySwN4FWce6QZwGU43tMwFHoIxsKrmZ3ZydQPfwdQjJjFjCdTaZhtEYS1Hcvu gg0yU5mjO/1frauqjgC/qo4ez/JrJr5aYHrV91o5S2w0Wl7jfUADAIRDLfhAnTe6 shbiPPBPJeY7EAt6JEytHBmlbwZLyE3zrB0GhlhyaKY344Z5k5Woq2u6zInPx5gi rtiWOUbuerBl8autaKwnPa9i+DSmRwMD8esFIyUMyCbPOMj89YirZtxWGD+ol71i cnBXV8DbX9aYfR8c8U3WNeR8FTOvxKYEC8cc3xErsustrwFlDKzlJD41VGHVZvjB qayuRIR/qMy+fy+8UrxzCFQA32gtZ/ZmjfyHWXHhe2DujThmTi95PtgpLHe1Y2Nh hYuGhj6fqzFvSvSJkE2uWlNPVIu7viBcF1bQEZz07OdYuvU+GbA8OK8q3EzCq+l3 l5uWSedwC4cdyNRxigFS =cgRe -----END PGP SIGNATURE-----

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Fwd: [darcs-users] Google Summer of Code
by Guillaume Hoffmann 30 Apr '13

30 Apr '13

---------- Forwarded message ---------- From: Ganesh Sittampalam <ganesh(a)earth.li> Date: 2013/4/25 Subject: [darcs-users] Google Summer of Code To: darcs-users <darcs-users(a)darcs.net> Hi, darcs.net will participating in Google Summer of Code this year, under the umbrella of haskell.org - Google will be allocating 1 or 2 extra slots specifically for Darcs. Time is a little short, as we'd originally thought this arrangement was coming to an end: the student application deadline is 1900UTC on next Friday (May 3rd). Please see http://darcs.net/GSoC for ideas and what to do next if you are interested in participating. The most important thing is to get in touch with us informally asap. Many thanks to Guillaume Hoffmann both for making our initial application to be a separate organisation (which was unfortunately rejected), and then for talking to Google and establishing that our existing arrangement of having a dedicated slot under the haskell.org umbrella could continue. Cheers, Ganesh _______________________________________________ darcs-users mailing list darcs-users(a)darcs.net http://lists.osuosl.org/mailman/listinfo/darcs-users

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Re: [Haskell-cafe] GSoC Push Notifications project - communicating with mobile devices
by Kristopher Micinski 29 Apr '13

29 Apr '13

On Mon, Apr 29, 2013 at 4:46 PM, Marcos Pividori <marcospividori(a)gmail.com> wrote: > Hi, thanks for your response! this really help me. > > * About the code in Spanish: I will replace it for an English version in the > next weeks. As Michael said, I had to write it in Spanish because it was a > project for my university. Sorry, I know it is not clear now. > No worries, I don't think this makes it bad, just harder to read for English speakers > * Kristopher, thanks for your comments and availability. Yes, I am looking > to provide a Haskell API to interface with these different push notification > services. I know that maybe it isn't enough to fill up a summer, so I will > get into account this ideas you gave me. I am thinking about some useful > tools I could provide to people programming for mobile devices. I would also be interested in hearing about what you come up with. I have a lot of experience with mobile hacking, and I'd be glad to help you validate ideas as they come to you, or point you at related material. >>"I would suggest also adding to your schedule writing up a >> Yesod app which has "back and forth" communication with a device, >> seeing what common problems pop up, and then writing an API for >> handling *that* as well. (That may broaden the scope of your project >> enough.)" > > I created this "back and forth" communication for the project I mentioned > before. But, a lot of things could be improved. For example, about > mantaining a state of the connection and being able to manage with a lot of > devices at the same time. (As I implemented this, I think it wont work > really well with a lot of devices). And I could develop a demo app for each > OS (Android, iOS, Windows Phone, etc) to manage this communication. > I 'll continue investigating, every contribution is welcome! The key aspects are to use Haskell to write as little as boilerplate code as possible. Then identify the common elements of the API for each and write a common API. That strikes me as the simple part. I'm not sure if it's sensible or not, but maybe it would be possible to formalize this "back and forth" computation using something similar to session types. Maybe next steps would be to automatically take the types in the program and generate a contract for the JSON sent between the device and server, which might give you some fun experience in type level programming. This is very hand wavy, so I'm not sure if that's realistic or not... Kris

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