Re: [Haskell-cafe] CFG specification and analysis directly in Haskell
Anton Tayanovskyy wrote: John Meacham's frisby library [1] did something similar, though the technique is not as well-known as it should be. Looks like an excellent library, thank you! Note that you don't need to give explicit names to your rules anymore, the monad can do that for you. I was using the names for a Show instance. I am assuming there is no syntax sugar to recover the name of the variable used in a binder as a String. Ah, good point. There is no referentially transparent way to recover the name of a variable. Best regards, Heinrich Apfelmus -- http://apfelmus.nfshost.com ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] haskell i18n best practices
Paulo Pocinho poci...@gmail.com wrote: I don't know if this is a bad habit, but I had already separated the dialogue text in the code with variables holding the respective strings. At this time, I thought there could be some other way than gettext. Then I figured how to import localisation data, that the program loads, from external files. The data type is basically a tuple with variable-names associated with strings. This is bit like the file-embed package [3]. Still uncomfortable with i18n, I learned about the article I18N in Haskell in yesod blog [4]. I'd like to hear more about it. What is considered the best practice for localisation? I can't help you with best practice for Haskell, and I don't think there is any. Gettext is probably the easiest approach, because it integrates nicely with the rest of the environment. It automatically uses the usual LANG and LC_* variables, which are used in Unix-like systems. An even simpler (but not necessarily easier) approach is to hard-code the languages in a Map and just look up the string you need. In this case you have to code the integration yourself. It somewhat sounds like you are targetting the Windows platform anyway. Personally I'd likely prefer Gettext for its integration and all the existing translation tools. In either case, the best practice is not to work with variables, but with a default language. You write your text strings in your default language (usually English), but wrap them in a certain function call. The function will try to look up a translated message for the current language. This makes both programming and translating easier. This is how I imagine it works (or should work): main :: IO () main = do tr - getTranslator putStrLn (tr This is a test.) The 'tr' function is called just '_' in other languages, but you can't use the underscore in Haskell. A translater (person) would use a program to search your entire source code for those translatable strings, then they would use a translation program, which shows an English string and asks them to enter the translated string over and over, until all strings are translated. Greets, Ertugrul -- nightmare = unsafePerformIO (getWrongWife = sex) http://ertes.de/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Indentation problem using Happy
I'm trying to use Happy for the first time, and I'm having trouble with this
very simple example:
= BEGIN: PolyParser.y =
{
module Main where
import Char ( isAlpha, isDigit, isSpace )
}
%name calc
%tokentype { Token }
%error { parseError }
%token
id { TokenId $$ }
',' { TokenCOMMA }
wombat { TokenWombat $$ }
%%
Poly: id ',' wombat
{
parseError :: [Token] - a
parseError _ = error Parse error
data Poly = Poly Int String deriving Show
data Token
= TokenId Int
| TokenCOMMA
| TokenWombat String deriving Show
lexer :: String - [Token]
lexer [] = []
lexer (c:cs)
| isSpace c = lexer cs
| isAlpha c = lexVar (c:cs)
| isDigit c = lexNum (c:cs)
lexer (',':cs) = TokenCOMMA : lexer cs
lexNum cs = TokenInt (read num) : lexer rest
where (num,rest) = span isDigit cs
lexVar cs =
case span isAlpha cs of
(wombat,rest) - TokenWombat wombat : lexer rest
(id,rest) - TokenId id : lexer rest
main = getContents = print . calc . lexer
}
= END: PolyParser.y =
The resulting PolyParser.hs has an indentation problem (second-to-last line,
below), so it won't compile.
happyReduce_1 = happySpecReduce_3 4 happyReduction_1
happyReduction_1 _
_
_
= HappyAbsSyn4
(parseError :: [Token] - a
parseError _ = error Parse error
Thank you in advance to anyone who can tell me where I've gone wrong.
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Re: [Haskell-cafe] haskell i18n best practices
On Thu, Sep 29, 2011 at 7:54 PM, Paulo Pocinho poci...@gmail.com wrote: Still uncomfortable with i18n, I learned about the article I18N in Haskell in yesod blog [4]. I'd like to hear more about it. Yesod's approach is pretty nice [1]. The idea is to have a data type with all your messages, like data Message = Hello | WhatsYourName | MyNameIs String | Ihave_apples Int GoodBye For each of your supported languages, you provide a rendering function (they may be in separate source files) render_en_US :: Message - String render_en_US Hello = Hello! render_en_US WhatsYourName = What's your name? render_en_US (MyNameIs name) = My name is ++ name ++ . render_en_US (Ihave_apples 0) = I don't have any apples. render_en_US (Ihave_apples 1) = I have one apple. render_en_US (Ihave_apples n) = I have ++ n ++ apples. render_en_US GoodBye = Good bye! render_pt_BR :: Message - String render_pt_BR Hello = Olá! render_pt_BR WhatsYourName = Como você se chama? render_pt_BR (MyNameIs name) = Eu me chamo ++ name ++ . render_pt_BR (Ihave_apples 0) = Não tenho nenhuma maçã. render_pt_BR (Ihave_apples 1) = Tenho uma maçã. render_pt_BR (Ihave_apples 2) = Tenho uma maçã. render_pt_BR (Ihave_apples n) = Tenho ++ show n ++ maçãs. render_pt_BR GoodBye = Tchau! Given those functions, you can construct something like type Lang = String render :: [Lang] - Message - String render (pt :_) = render_pt_BR render (pt_BR:_) = render_pt_BR render (en :_) = render_en_US render (en_US:_) = render_en_US render (_:xs) = render xs render _ = render_en_US So 'r = render [fr, pt]' will do the right thing. You just need to pass this 'r' around in your code. Using is easy and clear: putStrLn $ r Hello putStrLn $ r WhatsYourName name - getLine putStrLn $ r MyNameIs Alice putStrLn $ r (Ihave_apples $ length name `mod` 4) putStrLn $ r GoodBye This approach is nice for several reasons: - Builtin support for complicated messages. Making something like Ihave_apples in gettext would be hard. Each language has its own rules, and you need to encode all of them in your code. On this example, my render_pt_BR recognizes and treats differently the 2 apples case. If you didn't think about it when you wrote your code (using gettext), you'd need to change your code for pt_BR. - Fast processing. render as I've coded above looks at the language list just once. After that, it's just GHC's pattern matching. - Fast startup. No need to look for strings on the hard drive. - Flexible. You may try several extensions, depending on your needs (a) Using a type class (like Yesod) if you don't want one big data type. (b) Using Text instead of String. Or even Builder. The biggest drawback is lack of tool support and lack of translators' expertise. gettext has a lot of inertia and is used everywhere on a FLOSS system. But as Ertugrul Soeylemez said, if you're targeting Windows, _not_ using gettext should be an advantage (less pain while create installers). HTH, [1] http://hackage.haskell.org/packages/archive/yesod-core/0.9.2/doc/html/Yesod-Message.html -- Felipe. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Type family instances in Haddock?
Would it be useful/worthwhile to have type/data family instances show up in Haddock just as type class instances do? Regards, Sean ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] CAL or Frege as a Haskell replacement on JVM?
Hello, since there is no Haskell compiler/interpreter for JVM yet (considering LambdaVM outdated), then the question for kind of Haskell replacement on this platform is either CAL[1] or Frege[2]. I'd like to ask here those who have used either of those languages for your experience with it/them, what's more similar to Haskell (at least from your point of view) and what you like more as a Haskell replacement on JVM. Thanks! Karel [1]: http://openquark.org/Welcome.html [2]: http://code.google.com/p/frege/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Programming with arrows, exercises
2011/9/30 John Lask jvl...@hotmail.com: On 30/09/2011 7:15 AM, Sergey Mironov wrote: Hello. I am reading Programming with Arrows by John Hughes (very helpful and interesting!), the book has an exercises requiring a module called Circuits for checking the answer. There should be things like class ArrowCircuit and various functions related to digital logic circuits simulation. Does anybody know where can I find one? Thanks, Sergey ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe This was in the old arrows library I have attached a copy, it will probably need modification to compile. You should be able to use the examples with the current arrows library with a few mods. Yes, looks quite old. Unfotinately, it doesn't match the book.. I found that module I was looking for is in Appendix! Should I be more attentive.. Anyway, thank you! ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Handy abbreviations for using SciTE with Haskell
I often use SciTE for editing Haskell code. I wanted an easy way to type symbols such as ∀ (instead of forall), so I created a properties file that allows me to do that. I haven't seen anything similar online (I Googled first), so I made the code available online. You can find the file and instructions here: http://www.haskell.org/haskellwiki/Tips_for_using_SciTE_with_Haskell ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] module - package
Hello. How can I find which installed package a specified module belongs to? ghci or cabal or ghc-pkg? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] module - package
On Friday 30 September 2011, 21:04:48, Roman Beslik wrote: Hello. How can I find which installed package a specified module belongs to? ghci or cabal or ghc-pkg? $ ghc-pkg find-module Foo.Bar.Baz ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] haskell i18n best practices
On Thu, Sep 29, 2011 at 3:54 PM, Paulo Pocinho poci...@gmail.com wrote: Hello list. I've been trying to figure a nice method to provide localisation. An The grammatical framework excels at translation and localization -- it probably has the highest learning curve of the options; but it will generate the best / most accurate text depending on the target language: * http://www.grammaticalframework.org At first brush, it may seem like extreme overkill; but it is able to handle many, many infuriating corner cases (eg: properly forming discontinuous constituents, updating case / tense and number to agree with potentially variable quantities and genders, addressing the absence of yes and no in some languages, etc...) The language processing bits are expressed in a PMCFG grammar, which uses a syntax similar to haskell. The PMCFG compiles to a PGF file that can be loaded and used by a haskell module that implements the runtime, so it doesn't change your run-time requirements (if you already rely on haskell, there are also runtime implementations in javascript, java, c and python). --Rogan application is deployed using a conventional installer. The end-user is not required to have the Haskell runtimes, compiler or platform. The application should bundle ready to use translation data. What I am after is simple; an intuitive way that an interested translator, with little knowledge of Haskell, can look at and create valid translation data. This is what I've been looking at lately. The first thing I noticed was the GNU gettext implementation for Haskell. The wiki page [1] has a nice explanation by Aufheben. The hgettext package is found here [2]. I don't know if this is a bad habit, but I had already separated the dialogue text in the code with variables holding the respective strings. At this time, I thought there could be some other way than gettext. Then I figured how to import localisation data, that the program loads, from external files. The data type is basically a tuple with variable-names associated with strings. This is bit like the file-embed package [3]. Still uncomfortable with i18n, I learned about the article I18N in Haskell in yesod blog [4]. I'd like to hear more about it. What is considered the best practice for localisation? -- [1] http://www.haskell.org/haskellwiki/Internationalization_of_Haskell_programs [2] http://hackage.haskell.org/packages/archive/hgettext/ [3] http://hackage.haskell.org/package/file-embed [4] http://www.yesodweb.com/blog/2011/01/i18n-in-haskell ___ 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] haskell i18n best practices
On Fri, Sep 30, 2011 at 5:44 PM, Rogan Creswick cresw...@gmail.com wrote: The grammatical framework excels at translation and localization -- it probably has the highest learning curve of the options; but it will generate the best / most accurate text depending on the target language: * http://www.grammaticalframework.org At first brush, it may seem like extreme overkill; but it is able to handle many, many infuriating corner cases (eg: properly forming discontinuous constituents, updating case / tense and number to agree with potentially variable quantities and genders, addressing the absence of yes and no in some languages, etc...) The language processing bits are expressed in a PMCFG grammar, which uses a syntax similar to haskell. The PMCFG compiles to a PGF file that can be loaded and used by a haskell module that implements the runtime, so it doesn't change your run-time requirements (if you already rely on haskell, there are also runtime implementations in javascript, java, c and python). I've seen GF before, but I can't actually see how one would use it for localization. Are there any simple examples? Cheers, =) -- Felipe. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] [Haskell] mapM with Traversables
You can use Data.Sequence.fromList to go [a] - Seq a, though. So given f :: Monad m = a - m b you have import Data.Traversable as T import Data.Sequence as S g :: Monad m = [a] - m (S.Seq b) g = T.mapM f . S.fromList - ryan On Wed, Sep 28, 2011 at 6:20 PM, Marc Ziegert co...@gmx.de wrote: Hi Thomas, this should be on the haskell-cafe or haskell-beginners mailing list. Haskell@... is mainly for announcements. You have: f :: Monad m = a - m b Data.Traversable.mapM :: (Monad m, Traversable t) = (a - m b) - t a - m (t b) So, if you define g with g a = do Data.Traversable.mapM f a or in short g = Data.Traversable.mapM f , then the type will be g :: (Monad m, Traversable t) = t a - m (t b) instead of g :: [a] - m (Seq b) . Try using ghci to find these things out. It helps to get not confused with the types. Besides the missing Monad context, g misses a generic way to convert between different Traversables, which does not exist. You can only convert from any Traversable (imagine a Tree) toList; not all Traversables have a fromList function. For conversion, you might want to use Foldable and Monoid, fold to untangle and mappend to recombine; but any specific fromList function will surely be more efficient. Regards - Marc Original-Nachricht Datum: Wed, 28 Sep 2011 17:27:58 -0600 Von: thomas burt thedwa...@gmail.com An: hask...@haskell.org Betreff: [Haskell] mapM with Traversables Hi - I have a function, f :: Monad m = a - m b, as well as a list of a's. I'd like to produce a sequence (Data.Sequence) of b's, given the a's: g :: [a] - m (Seq b) g a = do Data.Traversable.mapM f a -- type error! I see that Data.Traversable.mapM f a doesn't work... is this like asking the compiler to infer the cons/append operation from the type signature of g? Do I need to write my own function that explicitly calls the append functions from Data.Sequence or can I do something else that would work for any g :: Traversable t, Traversable u = t a - m (u b) given f :: a - m b? Thanks for any comments! Thomas ___ 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] haskell i18n best practices
On Fri, Sep 30, 2011 at 2:09 PM, Felipe Almeida Lessa felipe.le...@gmail.com wrote: On Fri, Sep 30, 2011 at 5:44 PM, Rogan Creswick cresw...@gmail.com wrote: The grammatical framework excels at translation and localization -- it probably has the highest learning curve of the options; but it will generate the best / most accurate text depending on the target language: * http://www.grammaticalframework.org At first brush, it may seem like extreme overkill; but it is able to handle many, many infuriating corner cases (eg: properly forming discontinuous constituents, updating case / tense and number to agree with potentially variable quantities and genders, addressing the absence of yes and no in some languages, etc...) The language processing bits are expressed in a PMCFG grammar, which uses a syntax similar to haskell. The PMCFG compiles to a PGF file that can be loaded and used by a haskell module that implements the runtime, so it doesn't change your run-time requirements (if you already rely on haskell, there are also runtime implementations in javascript, java, c and python). I've seen GF before, but I can't actually see how one would use it for localization. Are there any simple examples? Here's a *very* simple example I just threw together, based on the Foods grammar (so it's quite contrived), but hopefully it's sufficient for the moment: https://github.com/creswick/gfI8N Updating it to use the Phrasebook example would make it much more interesting... I think there are numbers in there, and iirc, it uses the actual resource grammars, which is what you really want for a real system. Usage details in the README.md, and I've commented the important function in the haskell source. The rest of the magic is in the (also ugly) Setup.hs. You will also need to manually install gf, I believe, even if you use cabal-dev, due to some annoyingly complex (but solveable) build-order and PATH complications. --Rogan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Static linking for machines that don't have Haskell
Hi All, I am trying to run a Haskell program compiled on my Ubuntu box on a server box that does not have GHC installed and where I dont have root privileges. I run into several missing libraries, in particular libgmp, libffi and libuuid (the later two are needed by my program). How I can statically link my program such that I can run it on this server? I have a tried static linking as follows: * ghc -static -optl-static -optl-pthread --make -o p main.hs* This gives me several warnings of the form: */usr/lib/haskell-packages/ghc6/lib/network-2.2.1.7/ghc-6.12.3/libHSnetwork-2.2.1.7.a(BSD.o): In function `sw4B_info':* *(.text+0x584c): warning: Using 'getservbyport' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking* And sure enough the generated executable segfaults on the server which has a different glibc version. Is there some way to static link all the other libraries needed except glibc? I have looked around for an example of this but to no avail and the output of the -v switch seemed a bit overwhelming. Or is there some other way to go about doing this? thanks in advance, Roshan ps. including these, in case they maybe of some use: My machine: *$ ldd p* * linux-vdso.so.1 = (0x7fff3000)* * libncurses.so.5 = /lib/libncurses.so.5 (0x7fbdbbf4f000)* * libuuid.so.1 = /lib/x86_64-linux-gnu/libuuid.so.1 (0x7fbdbbd4a000)* * librt.so.1 = /lib/x86_64-linux-gnu/librt.so.1 (0x7fbdbbb41000)* * libutil.so.1 = /lib/x86_64-linux-gnu/libutil.so.1 (0x7fbdbb93e000)* * libdl.so.2 = /lib/x86_64-linux-gnu/libdl.so.2 (0x7fbdbb73a000)* * libpthread.so.0 = /lib/x86_64-linux-gnu/libpthread.so.0 (0x7fbdbb51b000)* * libgmp.so.3 = /usr/lib/libgmp.so.3 (0x7fbdbb2be000)* * libffi.so.5 = /usr/lib/libffi.so.5 (0x7fbdbb0b6000)* * libm.so.6 = /lib/x86_64-linux-gnu/libm.so.6 (0x7fbdbae3)* * libc.so.6 = /lib/x86_64-linux-gnu/libc.so.6 (0x7fbdbaa9c000)* * /lib64/ld-linux-x86-64.so.2 (0x7fbdbc1b5000)* Server: *$ ldd p* *./p: /lib64/libuuid.so.1: no version information available (required by ./p)* *linux-vdso.so.1 = (0x7fffc51fd000)* *libncurses.so.5 = /usr/lib64/libncurses.so.5 (0x0037bce0)* *libuuid.so.1 = /lib64/libuuid.so.1 (0x0037b720)* *librt.so.1 = /lib64/librt.so.1 (0x0037b5a0)* *libutil.so.1 = /lib64/libutil.so.1 (0x0037bda0)* *libdl.so.2 = /lib64/libdl.so.2 (0x0037b4a0)* *libpthread.so.0 = /lib64/libpthread.so.0 (0x0037b520)* *libgmp.so.3 = not found* *libffi.so.5 = not found* *libm.so.6 = /lib64/libm.so.6 (0x0037b4e0)* *libc.so.6 = /lib64/libc.so.6 (0x0037b460)* */lib64/ld-linux-x86-64.so.2 (0x0037b420)* * * ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
