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ANN: hledger 0.26
by Simon Michael 14 Jul '15

14 Jul '15

I'm pleased to announce hledger and hledger-web 0.26! This release restores non-regular-expression account aliases as the default, and brings miscellaneous bugfixes and cleanups and some performance work. Also the website and documentation have been improved, and now include many more examples. Full release notes: http://hledger.org/release-notes#hledger-0.26 . Release contributors: Simon Michael, Imuli, Carlos Lopez-Camey, Kyle Marek-Spartz, Rick Lupton, Simon Hengel. About: hledger (http://hledger.org) is a command-line tool and haskell library for tracking financial transactions, which are stored in a human-readable plain text format. It can also read CSV or timelog files, and output CSV. It provides useful reports, and can also help you record new transactions interactively. Add-on commands include hledger-web (a web interface), hledger-irr (for calculating internal rate of return) and hledger-interest (for generating interest transactions). hledger is inspired by and largely compatible with Ledger, and can be used with some Ledger files. Installation: $ cabal update [$ cabal sandbox init] $ cabal install hledger[-web]-0.26 or: install stack (https://github.com/commercialhaskell/stack/wiki/Downloads <https://github.com/commercialhaskell/stack/wiki/Downloads>) $ stack --resolver nightly-2015-07-13 install hledger [hledger-web] or: $ git clone https://github.com/simonmichael/hledger.git $ cd hledger $ git checkout hledger-0.26 $ stack install or see http://hledger.org/download for more options. Best! -Simon

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In " returnIO x = IO $ \ s -> (# s, x #)" what are the # symbols?
by Jeffrey Brown 14 Jul '15

14 Jul '15

That appears here: http://hackage.haskell.org/package/base-4.8.0.0/docs/src/GHC-Base.html#line…

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On Windows after I install the new cabal-install then when I do a cabal update it says there is a new ...
by KC 14 Jul '15

14 Jul '15

On Windows after I install the new cabal-install then when I do a cabal update it says there is a new cabal-install available. Yet cabal-install installed without any errors. Why do I get this message? -- -- Sent from an expensive device which will be obsolete in a few months! :D Casey

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Best way to return Bool based on a successful pattern match?
by Nikolay Amiantov 14 Jul '15

14 Jul '15

Hi Cafe, Every now and then I'm in a need to check if a value satisfies pattern with a Bool result. So far I know several ways to do this: 1. Use lens: `has _Left` 2. Make a function: `isLeft (Left _) = True; isLeft _ = False` 3. (When you need a lambda) Use LambdaCase: `\case Left _ -> True; _ -> False` Usually I go for (1) because I use lens extensively anyway, but for one-time usage all the extra machinery seems too much. I don't like (2) when I don't have a library defining that for me, and also (3) -- they seem inelegant. Is there any syntactic trick that I'm missing that makes it look nicer? -- Nikolay.

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To all users of FGL
by Ivan Lazar Miljenovic 13 Jul '15

13 Jul '15

As you may now, for the past few months I've been (finally!) cleaning up FGL, adding tests, etc. One of the issues that has arisen with this is that the behaviour of the delLEdge [1] function is not well specified when dealing with multiple edges. Specifically, the documentation states that the purpose is to "Remove *an* LEdge from the Graph." (emphasis added)... but the behaviour when dealing with multiple edges is to remove *all* such edges from the graph. The current version on GitHub is to instead just delete a single such labelled edge, with a new function "delAllLEdge" that replicates the current behaviour. Before releasing this change, however, I wanted to make sure that I wouldn't break people's code if they rely upon this functionality; I did try and search through GitHub to see who - if anyone - is using this function, but primarily found various copies of fgl embedded into other people's repositories. As such, please check your code and let me know if this change in behaviour might affect you (if this is the case, I might let delLEdge keep the current behaviour and have a new function delete just one edge). [1]: http://hackage.haskell.org/package/fgl-5.5.1.0/docs/Data-Graph-Inductive-Gr… -- Ivan Lazar Miljenovic Ivan.Miljenovic(a)gmail.com http://IvanMiljenovic.wordpress.com

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Re: [Haskell-cafe] Announcing libravatar @ hackage
by fr33domlover 13 Jul '15

13 Jul '15

Forgot the link, just in case: http://hackage.haskell.org/package/libravatar On 2015-07-12 fr33domlover <fr33domlover(a)riseup.net> wrote: > Hello! > > Libravatar - http://libravatar.org - is a free-as-in-freedom and decentralized > avatar (profile image delivery service, a replacement of the centralized and > proprietary grava7ar. > > There has been a Haskell library for grava7ar for some time, but not for > Libravatar. I just finished writing one, and did a bit of testing which had > good results. > > More testing and feedback etc. very very welcome! I also enourage you all to > *integrate libravatar into your desktop/web applications and websites*! > Support openness, decentralization and freedom by using Libravatar. > > > > --- > fr33domlover <http://www.rel4tion.org/people/fr33domlover> > GPG key ID: 63E5E57D (size: 4096) > GPG key fingerprint: 6FEE C222 7323 EF85 A49D 5487 5252 C5C8 63E5 E57D --- fr33domlover <http://www.rel4tion.org/people/fr33domlover> GPG key ID: 63E5E57D (size: 4096) GPG key fingerprint: 6FEE C222 7323 EF85 A49D 5487 5252 C5C8 63E5 E57D

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Announcing libravatar @ hackage
by fr33domlover 13 Jul '15

13 Jul '15

Hello! Libravatar - http://libravatar.org - is a free-as-in-freedom and decentralized avatar (profile image delivery service, a replacement of the centralized and proprietary grava7ar. There has been a Haskell library for grava7ar for some time, but not for Libravatar. I just finished writing one, and did a bit of testing which had good results. More testing and feedback etc. very very welcome! I also enourage you all to *integrate libravatar into your desktop/web applications and websites*! Support openness, decentralization and freedom by using Libravatar. --- fr33domlover <http://www.rel4tion.org/people/fr33domlover> GPG key ID: 63E5E57D (size: 4096) GPG key fingerprint: 6FEE C222 7323 EF85 A49D 5487 5252 C5C8 63E5 E57D

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idea: <package>-latest URLs for Hackage
by Ömer Sinan Ağacan 12 Jul '15

12 Jul '15

It's very convenient to have a persistent URL linked to latest version. GHC user manual has this(https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/) and you can create a bookmark with that URL and it stays up-to-date, it appears in first place in Google queries etc. I'm wondering why not implement this for Hackage too? For example, hackage.haskell.org/package/base-latest, hackage.haskell.org/package/base-latest/docs/<module-name>.html etc. Any ideas?

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Fwd: SQL database schema diff tool
by Sergey Mironov 12 Jul '15

12 Jul '15

---------- Forwarded message ---------- From: Sergey Mironov <grrwlf(a)gmail.com> Date: 2015-07-11 22:17 GMT+03:00 Subject: Re: [Haskell-cafe] SQL database schema diff tool To: David Kraeutmann <kane(a)kane.cx> Thanks for the answer, I've looked at simple-migrations application. Unfortunately, it doesn't look like the solution for me. Term 'migration' in PostgreSQL seems to mean 'movement of data from one server to another using the same schema', but I need to move the data from one schema to another as safely as possible having the definitions of both schemas. Regards, Sergey 2015-07-11 21:05 GMT+03:00 David Kraeutmann <kane(a)kane.cx>: > You could try https://github.com/ameingast/postgresql-simple-migration, but I haven't used it myself. "schema migration" seems to be what you want. > On 7/11/2015 7:54 PM, Sergey Mironov wrote: >> Hi, list! I wish I have a tool which would compare two database >> sachemas, where each schema is represented as a list of 'CREATE smth' >> instructions. The result of such a comparison would be a list of >> 'ALTER smth' instructions. This instruction set would change the >> database from first state to second, if the transition is possible >> without data losses. The 'hard' mode - to prepare the transition for >> any inputs, with minimal data losses. >> >> The database of interest is PostgreSQL. Does such a tool exist? If >> not, which package do I better use to build the AST of initial >> schemas? >> >> The example schema is in attach. >> Thanks in advance, >> Sergey >> >> >> >> _______________________________________________ >> Haskell-Cafe mailing list >> Haskell-Cafe(a)haskell.org >> http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe >> > >

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SQL database schema diff tool
by Sergey Mironov 12 Jul '15

12 Jul '15

Hi, list! I wish I have a tool which would compare two database sachemas, where each schema is represented as a list of 'CREATE smth' instructions. The result of such a comparison would be a list of 'ALTER smth' instructions. This instruction set would change the database from first state to second, if the transition is possible without data losses. The 'hard' mode - to prepare the transition for any inputs, with minimal data losses. The database of interest is PostgreSQL. Does such a tool exist? If not, which package do I better use to build the AST of initial schemas? The example schema is in attach. Thanks in advance, Sergey

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