Re: [Haskell-cafe] German names for kinds and sorts
Am 12.11.2011 17:05 schrieb Robert Clausecker: Hi all! I want to write my Facharbeit (kind of an essay you have to write on a specific topic you can choose yourself for highschool graduation) about the type-system of Haskell. It is required in our school to write this document in German language. Most time, it is not really difficult to find an appropriate term for concepts of Haskell, like types (Typen) or type classes (Typklassen). But I really don't know how to call kinds and sorts in German. Any ideas? Yours, Robert Clausecker Hi, there was a thread on the translation of the word "kind" [1] some years ago, have a look at this. I'm not exactly sure what a sort is so I can't help with that. Maybe just "Sorte"? Best wishes, Matthias [1] http://www.mail-archive.com/haskell@haskell.org/msg16752.html ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Problem with System.Timeout in Windows
Am 05.08.2010 07:35 schrieb Adolfo Builes: Hi All: I have been trying to use System.timeout in windows, but for some reason it doesn't work, a concrete example is: import Network.HTTP import System.Timeout main = do rsp <- timeout 1000 $ simpleHTTP $ getRequest "http://10.1.2.3"; case rsp of Just rsp -> print $ show rsp Nothing -> error "Nothing" In this case I would expect to receive "Nothing" after 10 seconds, but it ignores the timeout function. Hi Adolfo, the same behaviour for me with GHC 6.10.4 on Windows XP. If I set the timeout value to 0, I get *** Exception: Nothing immediately. Any other value results in *** Exception: connect: failed (Connection timed out (WSAETIMEDOUT)) after about 20 seconds. I don't know where the problem is, but I have similar problems with the threadDelay function. There must be something broken somewhere for some windows systems. Regards, Matthias ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Sockets get bound to wrong port on Windows
Am 03.06.2010 08:05 schrieb Ketil Malde:
Antoine Latter writes:
*Main> PortNum
47138
The PortNum constructor should rarely be used directly
So, shouldn't the constructor be hidden, and exported from an .Internal
module?
- it contains the port number in network-order. You should try:
Or perhaps even better, the type could be:
data PortNum = PortNum { msb, lsb :: Word8 }
so that we avoid this kind of confusion?
-k
Hi,
since this is really not obvious, I'd second to hide the constructor or
at least a note should be added to the docs how to use PortNumber correctly.
Regards,
Matthias
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Re: [Haskell-cafe] Re: Sockets get bound to wrong port on Windows
Am 03.06.2010 07:34 schrieb Bardur Arantsson: On 2010-06-03 05:10, Matthias Reisner wrote: Hi, there's something wrong with port numbers in the Network.Socket module of package network. Printing values gives: *Main> PortNum 47138 *Main> PortNum 47138 Try (fromIntegral ) :: PortNumber (Yes, it's weird.) Cheers, Bardur ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe Hi Bardur, indeed, this is weird. Thanks for the hint! Regards, Matthias ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Sockets get bound to wrong port on Windows
Am 03.06.2010 05:20 schrieb Ivan Miljenovic: So I thought it's just an error in the show instance of PortNumber, which shows the bytes flipped. But if I use the following code snippet sock <- socket AF_INET Datagram 0 bindSocket sock $ SockAddrInet (PortNum ) iNADDR_ANY to bind a socket to port , netstat and TCPView reveal that the socket is actually bound to the wrong port 47138. I'm using network-2.2.1.7 on Windows XP. Is that a bug or am I doing something wrong here? Tried testing this as well; not sure how to test if the binding worked but "netstat --numeric-ports" didn't contain or 47138. Hi Ivan, here's a complete program to reproduce the error: module Main (main) where import Network.Socket main :: IO () main = withSocketsDo $ do sock <- socket AF_INET Datagram 0 bindSocket sock $ SockAddrInet (PortNum ) iNADDR_ANY recvFrom sock 65535 return () The output of netstat/TCPView after starting the program is: MinSocketBind.exe:2724UDPPC1:47138*:* By the way, I'm using GHC 6.10.4, which I think shouldn't make a difference. Matthias ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Sockets get bound to wrong port on Windows
Hi, there's something wrong with port numbers in the Network.Socket module of package network. Printing values gives: *Main> PortNum 47138 *Main> PortNum 47138 So I thought it's just an error in the show instance of PortNumber, which shows the bytes flipped. But if I use the following code snippet sock <- socket AF_INET Datagram 0 bindSocket sock $ SockAddrInet (PortNum ) iNADDR_ANY to bind a socket to port , netstat and TCPView reveal that the socket is actually bound to the wrong port 47138. I'm using network-2.2.1.7 on Windows XP. Is that a bug or am I doing something wrong here? Regards, Matthias ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ANNOUNCE: Bravo-0.1.0
Am 12.03.2010 05:37 schrieb Matthias Reisner: Hi Michael Am 12.03.2010 01:33 schrieb Michael Snoyman: I'll need to look into the library a bit more to get a better idea, but it seems like Bravo could work for my needs. One thing that concerns me is your comment that it allows embedding of Haskell expressions. In general, I try to keep a strict separation between login and presentation: can you explain exactly what type of expressions can be embedded? This is really one disadvantage of the current Bravo version I'm worrying about too. At the moment you can insert arbitrary Haskell expressions, so no one prevents the template writer from inserting expressions like `unsafePerformIO launchAtomicMissile >> return ""'. Some kind of security mechanism will definitely be included in future releases, but I'm not sure in what way at the moment. I thought about passing a list of permitted function names to the template creation function and then failing with an error if any other functions are used. Today I thought about a security mechanism for Bravo and came to the simple solution: There actually is no need for it! If you don't trust your template writers, just do the following: Create a new module and import all functions you permit to be used in your templates (or hide functions from the Prelude). Call the template creation functions within this module and export all created data structures. Perhaps different templates may access different sets of permitted functions, so just create a module for each of these sets. Meanwhile I created the wiki page for Bravo and added an example that illustrates the problem (see http://www.haskell.org/haskellwiki/Bravo#Security_concerns). Finally, I can't seem to get it to compile on 6.12. Any chance of getting a version out that supports it? The problem seems to be haskell-src-meta, that doesn't like template-haskell-2.4, and on the other side I can't get build template-haskell < 2.4 with GHC-6.12. So I will contact Matt Morrow, the maintainer of haskell-src-meta, and see if he can fix it. Matt didn't reply yet, but there already is a patched haskell-src-meta version available at http://moonpatio.com/repos/haskell-src-meta_NEW_TH. I updated Bravo to be compatible with this version. Regards, Matthias ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Alternative dependencies in Cabal file
Thanks, I missed that the flags are set dynamically if a dependency cannot be satisfied. Am 17.03.2010 13:23 schrieb Daniel Fischer: Am Mittwoch 17 März 2010 12:11:53 schrieb Matthias Reisner: Hi, for a package I need to ensure the user uses a certain package configuration. So how would I rewrite the following pseudo-cabal description? Build-Depends: packageA < X, packageB < Y or packageA >= X && < X', packageB >= Y && < Y' or packageA >= X', packageB >= Y' Build-Depends: ... common dependencies ... where neither A nor B is the base package. Maybe I have to use if/else blocks, but I don't know what conditions to use then. Read http://www.haskell.org/ghc/docs/latest/html/Cabal/authors.html for a general description of what you can do, I'd try something like in http://hackage.haskell.org/packages/archive/cabal-install/0.8.0/cabal- install.cabal flag oldAB description: ancient packages A and B default: False flag newAB description: shiny new A and B Library blubb build-depends: common, libraries if flag(newAB) build-depends: packageA >= X', packageB >= Y' else if flag(oldAB) build-depends: packageA < X, packageB < Y else build-depends: packageA >= X && < X', packageB >= Y && < Y' If I remember correctly, that tries first to build against the new A and B, that failing, it sets flag newAB to false and tries again, first with the not-so-ancient A and B, hopefully (but I'm not sure about the order in which flags are toggled if the defaults don't give a successful install plan). Regards, Matthias ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Alternative dependencies in Cabal file
Hi, for a package I need to ensure the user uses a certain package configuration. So how would I rewrite the following pseudo-cabal description? Build-Depends: packageA < X, packageB < Y or packageA >= X && < X', packageB >= Y && < Y' or packageA >= X', packageB >= Y' Build-Depends: ... common dependencies ... where neither A nor B is the base package. Maybe I have to use if/else blocks, but I don't know what conditions to use then. Regards, Matthias ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ANNOUNCE: Bravo-0.1.0
Hi Michael Am 12.03.2010 01:33 schrieb Michael Snoyman: I'll need to look into the library a bit more to get a better idea, but it seems like Bravo could work for my needs. One thing that concerns me is your comment that it allows embedding of Haskell expressions. In general, I try to keep a strict separation between login and presentation: can you explain exactly what type of expressions can be embedded? This is really one disadvantage of the current Bravo version I'm worrying about too. At the moment you can insert arbitrary Haskell expressions, so no one prevents the template writer from inserting expressions like `unsafePerformIO launchAtomicMissile >> return ""'. Some kind of security mechanism will definitely be included in future releases, but I'm not sure in what way at the moment. I thought about passing a list of permitted function names to the template creation function and then failing with an error if any other functions are used. Also, while looking through the example, it looks like the library is making some automatic translations, like firstName -> userFirstName and user -> users. I've found these kinds of mappings to be brittle in the past; can you explain how this is done (or if I'm simply missing something obvious)? Bravo creates a data type per template, where the default naming scheme for the data type/constructor name is "name" -> "TplName". For each template variable a record field is created; for a template "temp" and a variable "var" the name will be "tempVar". Have a look at the `mkTemplatesWithOptions' and `mkTemplatesFromFileWithOptions' functions, that allow you to customize this naming scheme. Finally, I can't seem to get it to compile on 6.12. Any chance of getting a version out that supports it? The problem seems to be haskell-src-meta, that doesn't like template-haskell-2.4, and on the other side I can't get build template-haskell < 2.4 with GHC-6.12. So I will contact Matt Morrow, the maintainer of haskell-src-meta, and see if he can fix it. Regards, Matthias Thanks, Michael On Wed, Mar 10, 2010 at 8:46 PM, Matthias Reisner < matthias.reis...@googlemail.com> wrote: Hello, I'm pleased to announce the first release of Bravo, a static text template generation library, on Hackage: http://hackage.haskell.org/package/Bravo. Bravo is a text template library that provides parsing and generation of templates at compile time. Templates can be read from strings or files and for each a new record data type is created, allowing convenient access to all template variables in a type-safe manner. Since all templates are processed at compile time, no extra file access or error handling at runtime is necessary. Bravo is inspired by the PHP template engine Smarty and the Haskell template library chunks. Compared to chunks, Bravo provides additional features like conditional template evaluation, embedding of Haskell expressions and customized data type generation. I'm going to add further information to the HaskellWiki page ( http://www.haskell.org/haskellwiki/Bravo) later. Bravo is still highly experimental and not well-tested, so bug reports and additional feedback are very welcome. I'd also like to hear if you feel the package dependencies are to restrictive. Regards, Matthias Reisner ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: ANNOUNCE: Bravo-0.1.0
Am 11.03.2010 23:38 schrieb Simon Michael: Thank you, how does it compare to HStringTemplate ? Hi Simon, I never worked with HStringTemplate, so as far as I can tell after having a glance at the HStringTemplate API and the wiki page, the main difference is that Bravo parses the templates at compile time, while HStringTemplate does at runtime. Besides that, HStringTemplate provides several methods for rendering different data types in different styles. This can also be accomplished in Bravo by writing the appropriate rendering function in your Haskell code and using it in the template. Regards, Matthias ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: [Haskell] ANNOUNCE: Bravo-0.1.0
Hi Marc, I'm sorry, the current Bravo version does not support caching of evaluated templates. Maybe this will be a feature of later releases. Matthias Am 11.03.2010 10:02 schrieb Marc Weber: Hi Matthias, Bravo is inspired by the PHP template engine Smarty and the Haskell Smarty is also about caching. Can you say whether your library support kind of caching as well? Marc Weber ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] ANNOUNCE: Bravo-0.1.0
Hello, I'm pleased to announce the first release of Bravo, a static text template generation library, on Hackage: http://hackage.haskell.org/package/Bravo. Bravo is a text template library that provides parsing and generation of templates at compile time. Templates can be read from strings or files and for each a new record data type is created, allowing convenient access to all template variables in a type-safe manner. Since all templates are processed at compile time, no extra file access or error handling at runtime is necessary. Bravo is inspired by the PHP template engine Smarty and the Haskell template library chunks. Compared to chunks, Bravo provides additional features like conditional template evaluation, embedding of Haskell expressions and customized data type generation. I'm going to add further information to the HaskellWiki page (http://www.haskell.org/haskellwiki/Bravo) later. Bravo is still highly experimental and not well-tested, so bug reports and additional feedback are very welcome. I'd also like to hear if you feel the package dependencies are to restrictive. Regards, Matthias Reisner ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
