Re: [Haskell-cafe] One-element tuple
Can you please elaborate why this inconsistency is annoying and what's the use of OneTuple? Genuine question, thanks. On Fri, Aug 16, 2013 at 5:35 AM, AntC anthony_clay...@clear.net.nz wrote: There's an annoying inconsistency: (CustId 47, CustName Fred, Gender Male) -- threeple (CustId 47, CustName Fred)-- twople -- (CustId 47)-- oneple not! () -- nople (That is, it's annoying if you're trying to make typeclass instances for extensible/contractable tuples. Yes, I know I could use HLists.) I'm not happy with either approach I've tried: data Oneple a = Oneple a -- (or newtype) (Oneple $ CustId 47) -- too verbose type Oneple a = [a] [CustId 47] -- at least looks bracket-y What do you do? AntC ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Sincerely yours, -- Daniil ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Errors in non-monadic code
On Mon, Aug 19, 2013 at 9:48 PM, jabolo...@google.com wrote: Hi, Hello! What is the proper way to implement a non-monadic function that checks whether a given value is correct and gives a proper error message otherwise ? What is the recommended option ? I am not sure, what do you mean by non-monadic. Both (Either String) and Maybe are monads. You can pick up whatever option you like, depending on which option, in your opinion, suits you better for your specific case. There is also a helpful errors [1] package that provide convenient means of converting between the results of the two approaches. Control.Error.Util.hush :: Either a b - Maybe b Control.Error.Util.note :: a - Maybe b - Either a b * Either String a check val | valid val = Right val | otherwise = Left errorMsg * Maybe String check val | valid val = Nothing | otherwise = Just errorMsg Cheers, Jose ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe [1] http://hackage.haskell.org/package/errors -- Sincerely yours, -- Daniil ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] ANN: restricted-workers-0.1
Introducing: restricted-workers library, version 0.1.0. This library provides an abstract interface for running various kinds of workers under resource restrictions. It is being developed as part of the interactive-diagrams project and you can read more about the origins of the library in my GSoC report: http://parenz.wordpress.com/2013/07/15/interactive-diagrams-gsoc-progress-report/ The library provides a convenient way of running worker processes, saving data obtained by the workers at start-up, a simple pool abstraction and a configurable security and resource limitations. Right now there are several kinds of security restrictions that could be applied to the worker process: - RLimits - chroot jail - custom process euid - cgroups - process niceness - SELinux security context You can read more about the library on the wiki: https://github.com/co-dan/interactive-diagrams/wiki/Restricted-Workers The library has been uploaded to hackage and you can install it using cabal-install. -- Thanks -- Daniil Frumin ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Dual-licensing the package on Hackage
I second this. Also, I would like to point out that the product you get from Hackage (the source code) will be licensed under the GPL. Nobody can get the commercial version of the product from Hackage, as one has to contact you (the owner) directly or in some other manner. I guess that is what Thu is trying to say. On Tue, Jul 30, 2013 at 3:03 PM, Vo Minh Thu not...@gmail.com wrote: No. If I provide a library to you stating you can use it under the term of the GPL3, this does not prevent me from providing it to someone else under a different license (provided I have the rights to do so, for instance because I am the copyright owner). So as far as you're concerned (and this is the case with Hackage in this dicussion), the library is provided under the terms of the GPL. There is no point saying but if you pay me I can provide it under some other terms. 2013/7/30 Jan Stolarek jan.stola...@p.lodz.pl: I'd say OtherLicense because: data License = GPL3 is different from data License = Commercial | GPL3 I hope this analogy to Haskell data types is convincing :) Janek - Oryginalna wiadomość - Od: David Sorokin david.soro...@gmail.com Do: Vo Minh Thu not...@gmail.com DW: Haskell Cafe haskell-cafe@haskell.org Wysłane: wtorek, 30 lipiec 2013 11:46:00 Temat: Re: [Haskell-cafe] Dual-licensing the package on Hackage I am inclined to use value OtherLicense but state in the description that the package is available either under GPL or a commercial license. The latter must be requested to me. Then there would be no required additional steps to use the package under GPL. Only the LICENSE file must be appropriate. Probably, I will need two files LICENSE and LICENSE-GPLv3. In the former I will have add my copyright and write in a simple form that the license is dual and everyone is free to use the library under GPLv3 (which is the main use case) according the terms provided in the corresponded second file. Thanks, David On 30.07.2013 13:57, Vo Minh Thu wrote: Unless you want to provide multiple open source licenses, I don't see the point: Anybody that needs a commercial license (and has some money) will simply ask for such a commercial license when seeing that the code is available under GPL. Another reason it is pointless is that you will certainly not want to list all the commercial licenses you have used/will use with different clients (there are virtually infinite commercial licenses that you can invent as needs arise: per seat, per core, per year, and so on depending on the clients/projects). I.e. you don't need to state upfront that commercial licences exist (although I understand that you think it is better to advertise your willingness to provide such commercial license, but a comment is enough, the fact is that license is not provided through Hackage). 2013/7/30 Krzysztof Skrzętnicki gte...@gmail.com: Perhaps it would be best if .cabal allowed to have more than one license listed. Another solution would be to use custom field, for example: License: GPL x-Other-License: Commercial, see License-Commercial.txt All best, Krzysztof Skrzętnicki On Tue, Jul 30, 2013 at 11:44 AM, David Sorokin david.soro...@gmail.com wrote: Thanks Thu, I agree with you. Just I don't know what to write in the license field of the .cabal file: GPL or OtherLicense. The both choices seem correct to me and misleading at the same time. Cheers, David 30.07.2013, в 12:53, Vo Minh Thu написал(а): 2013/7/30 David Sorokin david.soro...@gmail.com: Hi, Cafe! Probably, it was asked before but I could not find an answer with help of Google. I have a library which is hosted on Hackage. The library is licensed under BSD3. It is a very specialized library for a small target group. Now I'm going to relicense it and release a new version already under the dual-license: GPLv3 and commercial. In most cases GPL will be sufficient as this is not a library in common sense. Can I specify the GPL license in the .cabal file, or should I write OtherLicense? I'm going to add the information about dual-licensing in the description section of the .cabal file, though. Although you can indeed license your software under different licences, in the case of your question it doesn't seem to be a concern with Hackage: The license displayed on Hackage is the one for the corresponding .cabal file (or at least I think it is). So you issue your new version with the changed license, the new version is available with the new license, the old versions are still available with the old license. Everything is fine. Now about the dual licensing. It seems it is again not a problem with Hackage: you are not granting through Hackage such a commercial license. I guess you provide it upon request (for some money). I.e. when I download your library from Hackage, I receive it under the terms of the BSD (or GPL) license you have chosen, not under a commercial
Re: [Haskell-cafe] What have happened to haskell.org?
The web site is migrating. IRC says: Topic for #haskell: haskell.org in the middle of migration; expect turbulence; use www.haskell.org On Mon, Jul 15, 2013 at 6:19 PM, Kirill Zaborsky qri...@gmail.com wrote: On URL http://haskell.org/ I get starting Apache page and 404 on http://haskell.org/hoogle/ URL with starting www - http://www.haskell.org/ seems to be working but http://www.haskell.org/hoogle/ responds with some ELF file. Kind regards, Kirill Zaborsky ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Sincerely yours, -- Daniil -- Sincerely yours, -- Daniil ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Hoogle problems?
The web site is migrating. IRC says: Topic for #haskell: haskell.org in the middle of migration; expect turbulence; use www.haskell.org On Mon, Jul 15, 2013 at 5:35 PM, Andrew Butterfield andrew.butterfi...@scss.tcd.ie wrote: I've just tried using Hoogle, but either get a 404 not found (http://haskell.org/hoogle/) or else I find I get a ELF 64-bit LSB executable being downloaded If I search using Google and click on the first link (shown as www.haskell.org/hoogle/ I get the following (spaces deliberately added to make it less dangerous) https://www.goo gle.com/url?sa=trct=jq=esrc=ssou rce=webcd=1cad=rjaved=0CC8QFjAAurl=http%3A%2F%2Fwww.haskell.org%2Fhoogle%2Fei=y_njUdZAhY 7sBsGpgNAKusg=AFQjCNFljq5Oyb4LT7VF-I5MUotq512AQgsig2 =SVRE_6nF3bhho7-NKqEaCwbvm=bv.487 05608,d.ZGU Using Mac OS X 10.6, Chrome and Safari Is it me, or is there a wider problem ? Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Lero@TCD, Head of Foundations Methods Research Group Director of Teaching and Learning - Undergraduate, School of Computer Science and Statistics, Room G.39, O'Reilly Institute, Trinity College, University of Dublin http://www.scss.tcd.ie/Andrew.Butterfield/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Sincerely yours, -- Daniil ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] [GSoC] Interactive-diagrams GSoC progress report
Hello everyone, I am participating in Haskell.org's Google Summer of Code, working on the interactive-diagrams [1] project. The mid-term evaluations are approaching and I am doing some writeup on the work I did so far: http://parenz.wordpress.com/2013/07/15/interactive-diagrams-gsoc-progress-report/ A beta-version of the site is also available to the public: http://paste.hskll.org Please note that this is not a final product and you may experience cryptic error messages, some downtime. The security is pretty tight though :) Any suggestions/comments are welcome. [1] https://google-melange.appspot.com/gsoc/proposal/review/google/gsoc2013/difrumin/1 -- Sincerely yours, -- Daniil Frumin ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Problems with GHC API and error handling
OK, thanks to Luite Stegeman I've found the solution and I think I'll
post it here in case someone else stumbles upon the same problem.
The solution is the following: you have to change 'log_action'
parameter in dynFlags. For example, one can do this:
---
initGhc = do
..
ref - liftIO $ newIORef
dfs - getSessionDynFlags
setSessionDynFlags $ dfs { hscTarget = HscInterpreted
, ghcLink = LinkInMemory
, log_action = logHandler ref}
logHandler :: IORef String - LogAction
logHandler ref dflags severity srcSpan style msg =
case severity of
SevError - modifyIORef' ref (++ printDoc)
SevFatal - modifyIORef' ref (++ printDoc)
_ - return ()
where cntx = initSDocContext dflags style
locMsg = mkLocMessage severity srcSpan msg
printDoc = show (runSDoc locMsg cntx)
-- LogAction == DynFlags - Severity - SrcSpan - PprStyle - MsgDoc - IO ()
---
On Sat, Jun 15, 2013 at 1:26 PM, Daniel F difru...@gmail.com wrote:
Hello, everyone.
I am in need of setting up custom exception handlers when using GHC
API to compile modules. Right now I have the following piece of code:
* Main.hs:
--
import GHC
import GHC.Paths
import MonadUtils
import Exception
import Panic
import Unsafe.Coerce
import System.IO.Unsafe
handleException :: (ExceptionMonad m, MonadIO m)
= m a - m (Either String a)
handleException m =
ghandle (\(ex :: SomeException) - return (Left (show ex))) $
handleGhcException (\ge - return (Left (showGhcException ge ))) $
flip gfinally (liftIO restoreHandlers) $
m = return . Right
initGhc :: Ghc ()
initGhc = do
dfs - getSessionDynFlags
setSessionDynFlags $ dfs { hscTarget = HscInterpreted
, ghcLink = LinkInMemory }
return ()
test :: IO (Either String Int)
test = handleException $ runGhc (Just libdir) $ do
initGhc
setTargets = sequence [ guessTarget ./test/file1.hs Nothing ]
graph - depanal [] False
loaded - load LoadAllTargets
-- when (failed loaded) $ throw LoadingException
setContext (map (IIModule . moduleName . ms_mod) graph)
let expr = main
ty - exprType expr -- throws exception if doesn't typecheck
output ty
res - unsafePerformIO . unsafeCoerce $ compileExpr expr
return res
--
* file1.hs:
module Main where
main = do
return x
The problem is when I run the 'test' function above I receive the
following output:
h test
test/file1.hs:4:10: Not in scope: `x'
Left Cannot add module Main to context: not a home module
it :: Either String Int
So, if I understand this correctly, my exception handler does indeed
catch an exception correctly,
however, I still receive some output which I want to be captured.
Is there a way to do this?
--
Sincerely yours,
-- Daniil Frumin
--
Sincerely yours,
-- Daniil
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[Haskell-cafe] Problems with GHC API and error handling
Hello, everyone.
I am in need of setting up custom exception handlers when using GHC
API to compile modules. Right now I have the following piece of code:
* Main.hs:
--
import GHC
import GHC.Paths
import MonadUtils
import Exception
import Panic
import Unsafe.Coerce
import System.IO.Unsafe
handleException :: (ExceptionMonad m, MonadIO m)
= m a - m (Either String a)
handleException m =
ghandle (\(ex :: SomeException) - return (Left (show ex))) $
handleGhcException (\ge - return (Left (showGhcException ge ))) $
flip gfinally (liftIO restoreHandlers) $
m = return . Right
initGhc :: Ghc ()
initGhc = do
dfs - getSessionDynFlags
setSessionDynFlags $ dfs { hscTarget = HscInterpreted
, ghcLink = LinkInMemory }
return ()
test :: IO (Either String Int)
test = handleException $ runGhc (Just libdir) $ do
initGhc
setTargets = sequence [ guessTarget ./test/file1.hs Nothing ]
graph - depanal [] False
loaded - load LoadAllTargets
-- when (failed loaded) $ throw LoadingException
setContext (map (IIModule . moduleName . ms_mod) graph)
let expr = main
ty - exprType expr -- throws exception if doesn't typecheck
output ty
res - unsafePerformIO . unsafeCoerce $ compileExpr expr
return res
--
* file1.hs:
module Main where
main = do
return x
The problem is when I run the 'test' function above I receive the
following output:
h test
test/file1.hs:4:10: Not in scope: `x'
Left Cannot add module Main to context: not a home module
it :: Either String Int
So, if I understand this correctly, my exception handler does indeed
catch an exception correctly,
however, I still receive some output which I want to be captured.
Is there a way to do this?
--
Sincerely yours,
-- Daniil Frumin
___
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