Re: [Haskell-cafe] Why does sleep not work?
I can confirm this behaviour, on: Linux 2.6.27-11-generic #1 SMP i686 GNU/Linux Difference in the RTS between non-working and working: (RTS way, rts_thr) (RTS way, rts) - George signature.asc Description: This is a digitally signed message part ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haddock Markup
Am Dienstag, 10. Februar 2009 02:56 schrieben Sie: On 10 Feb 2009, at 1:19 am, Wolfgang Jeltsch wrote: This is only true if your destination format is PDF, DVI or PS. For a webpage, you’ll need MathML in the end and TeX is not so good in producing MathML, I suppose. Hmm. I find designed-for-HTML documentation horrible. I did *not* want to argue pro “designed-for-HTML”. I wanted to argue contra “designed-for-PDF” and pro “designed-for-any-output-format”. Best wishes, Wolfgang ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell and Java interaction
Am Montag, 9. Februar 2009 22:58 schrieb Robert Greayer: I'm sure this isn't the solution you are looking for, but when I had to do something similar (integrate an Eclipse plugin to Haskell code) the simplest approach I found was to simply invoke the Haskell in a separate process, binding the stdin/stdout of the Haskell process to Java output/input streams. Perhaps low-tech, but has worked well for me. For communication between Haskell software and Eclipse, there is also Cohatoe (http://eclipsefp.sourceforge.net/cohatoe/index.html). Interally, it works similar to what you described, as far as I know. Best wishes, Wolfgang ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Painting logs to get a coloured tree
Hi, Am Montag, den 09.02.2009, 16:41 -0700 schrieb Luke Palmer: 2009/2/9 Joachim Breitner m...@joachim-breitner.de Now while this works, and while ST is still somewhat pure, I'm wondering if there is no better way of expressing This piece of information came from the point in a data structure, so something else can be put here easily. You might want to look into zippers: http://haskell.org/haskellwiki/Zipper I thought about Zippers, but I understand that they improve _navigating_ in a Tree-like structure, or to refrence _one_ position in a tree. But if I would deconstruct my tree to the list of _all_ locations, with type Loc a = (Tree a, Cxt a) and then run my algorithm that returns [(Loc a, Info)], it’s still not clear to me how I can combine all of these locations to get back my original Tree, annotated with the Info returned. Thanks nevertheless, Joachim -- Joachim nomeata Breitner mail: m...@joachim-breitner.de | ICQ# 74513189 | GPG-Key: 4743206C JID: nome...@joachim-breitner.de | http://www.joachim-breitner.de/ Debian Developer: nome...@debian.org signature.asc Description: Dies ist ein digital signierter Nachrichtenteil ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Painting logs to get a coloured tree
2009/2/10 Joachim Breitner m...@joachim-breitner.de: Hi, Am Montag, den 09.02.2009, 16:41 -0700 schrieb Luke Palmer: 2009/2/9 Joachim Breitner m...@joachim-breitner.de Now while this works, and while ST is still somewhat pure, I'm wondering if there is no better way of expressing This piece of information came from the point in a data structure, so something else can be put here easily. You might want to look into zippers: http://haskell.org/haskellwiki/Zipper I thought about Zippers, but I understand that they improve _navigating_ in a Tree-like structure, or to refrence _one_ position in a tree. But if I would deconstruct my tree to the list of _all_ locations, with type Loc a = (Tree a, Cxt a) and then run my algorithm that returns [(Loc a, Info)], it's still not clear to me how I can combine all of these locations to get back my original Tree, annotated with the Info returned. I guess I just repeat your last praragraph of your original mail but it seems to me you can mapAccump some 'names' on the tree, process an association list (or an IntMap) of the (name,log) then map the three again using the result. In spirits, it's the same thing than the STRef solution but it seems cleaner to me. Cheers, Thu ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Painting logs to get a coloured tree
2009/2/10 minh thu not...@gmail.com: 2009/2/10 Joachim Breitner m...@joachim-breitner.de: Hi, Am Montag, den 09.02.2009, 16:41 -0700 schrieb Luke Palmer: 2009/2/9 Joachim Breitner m...@joachim-breitner.de Now while this works, and while ST is still somewhat pure, I'm wondering if there is no better way of expressing This piece of information came from the point in a data structure, so something else can be put here easily. You might want to look into zippers: http://haskell.org/haskellwiki/Zipper I thought about Zippers, but I understand that they improve _navigating_ in a Tree-like structure, or to refrence _one_ position in a tree. But if I would deconstruct my tree to the list of _all_ locations, with type Loc a = (Tree a, Cxt a) and then run my algorithm that returns [(Loc a, Info)], it's still not clear to me how I can combine all of these locations to get back my original Tree, annotated with the Info returned. I guess I just repeat your last praragraph of your original mail but it seems to me you can mapAccump some 'names' on the tree, process an association list (or an IntMap) of the (name,log) then map the three again using the result. In spirits, it's the same thing than the STRef solution but it seems cleaner to me. I forgot to mention you can try to tie the knot too, using the result of the processing in the first mapping (and then you don't need the second one)... ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Painting logs to get a coloured tree
If I understand you correctly, the problem is to annotate an already constructed tree with arbitrary pieces of new data -- hopefully without reconstructing the tree. Perhaps the approach used in the FLOLAC type-checkers would be helpful. The `tree' was an expression in lambda-calculus to type check. The new annotations are the reconstructed types, of each node in the tree (of each sub-expression). I wanted to annotate each sub-expression with its reconstructed type -- without re-defining the data type of expressions or rebuilding the tree. The expression should stay as it was, I merely want to associate, after the fact, additional pieces of data with each node. I also wanted the code to be pure and avoid STRefs let alone StableNames and any IO. Here are the files in question: http://okmij.org/ftp/Computation/FLOLAC/TEvalNC.hs http://okmij.org/ftp/Computation/FLOLAC/TEvalNR.hs TEvalNC.hs is the ordinary type checker for the simply-typed lambda calculus with constants and the fix-point. The type reconstructor (aka, non-standard, abstract evaluator) has this type teval :: TEnv - Term - Typ Given the type environment and a term, it returns its inferred type (or reports an error). The file TEvalNR.hs returns not only the reconstructed type of the term but also the types of all the subterms. The latter data are returned in a `virtual' typed AST -- virtual because the original AST is not modified and the inferred types are attached to AST nodes, well, virtually. Generally speaking, after a simple modification teval could be made total: it would return reconstructed types of the subterms even if the entire term is ill-typed. That modification was one of the exercises. The intention was to model OCaml -- which, given a special flag, can dump the inferred types of all sub-expressions, even if the overall type checking failed. In Emacs and vi, one can highlight an expression or variable and see its inferred type. If the type checking failed, one can still explore what the type checker did manage to infer. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Painting logs to get a coloured tree
Hi, Am Dienstag, den 10.02.2009, 10:05 +0100 schrieb minh thu: I forgot to mention you can try to tie the knot too, using the result of the processing in the first mapping (and then you don't need the second one)... could you elaborate who to tie that particular knot? I unfortunately, I don’t see it. Thanks, Joachim -- Joachim nomeata Breitner mail: m...@joachim-breitner.de | ICQ# 74513189 | GPG-Key: 4743206C JID: nome...@joachim-breitner.de | http://www.joachim-breitner.de/ Debian Developer: nome...@debian.org signature.asc Description: Dies ist ein digital signierter Nachrichtenteil ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Painting logs to get a coloured tree
Joachim Breitner wrote: Assume you have a tree (and you can think of a real tree here), defined by something like this: data Tree a = Bud | Branch a Double Tree Tree -- | ` Lenght of this branch -- ` General storage field for additional information Now, I have a nice algorithm that calulates something for each branch, but it only works on lists of branches, so I have to cut them apart first, remembering their position in space, and then work on these, well, logs. data Point = Point Double Double data Log = Log Point Point type Info = ... noInfo :: Info cutTreeApart :: Tree a - [(Log, a)] someAlgorithm :: [(Log,a)] - [(a, Info)] Conveniently, the algorithm allows me to tag the logs with something, to be able to keep track at least somewhat of the logs. [...] Some ideas where numbering the Nodes and then using this number as the tag on the log, but this is not much different from using STRefs, it seems. Yes, tagging the logs with their position in the tree isn't really different from using STRefs. There are many options for representing positions (depth/breath first numbers; paths like [L,R,L,...] etc.) but in the end, it boils down to the same thing. Here's an example with with numbers annotate tree = thread tree (\(x:xs) - (x,xs)) . map snd . sort (comparing fst) . someAlgorithm . cutTreeApart . thread tree (\n - (n, succ n)) $ (0 :: Int) where thread tree f x = evalState (mapM (const $ State f) tree) x However, I would be surprised if someAlgorithm could not be formulated directly on the tree or at least satisfies a few invariants like for example map fst . someAlgorithm = map snd Also, how does cutTreeApart arrange the list? The idea is that most of the tree structure survives in the list and can be reconstructed. Regards, apfelmus -- http://apfelmus.nfshost.com ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haddock Markup
Wolfgang Jeltsch schrieb: This reminds me of an idea which I had some time ago. The idea is to write all your documentation in Template Haskell, possibly using quasiquoting to support Haddock-like syntax. Then you could write math as ordinary Haskell expressions and embed these expressions into your documentation expressions. This would make the documentation language very extensible since you could always write your own extensions in the form of some Haskell code fragments or libraries. If Template Haskell is capable of such processing that we be great since we wouldn't need to develop a new tool, but can concentrate on writing the transformations to TeX, MathML and so on. And if someone wants to include chemical formulas he may write appropriate transformations himself, upload them to Hackage, and cabal will be able to install them when needed. Everything becomes scalable, extensible, flexible and everything becomes great. Even versioning conflicts will become possible for documentation generation. :-) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Darcs 2.2.0 diff on Windows
When using this inside the Windows command prompt (CMD.EXE) I get darcs: diff: runInteractiveProcess: does not exist (No such file or directory) It works fine under MSYS. Also when using --diff-command to launch a GUI diff tool, Darcs does not seem to copy any changes the GUI tool did to the new-program. Is this intended behavior? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Haddock Markup
Heinrich Apfelmus schrieb:
Henning Thielemann wrote:
I want for long to write math formulas in a paper in Haskell. Actually,
lhs2TeX can do such transformations but it is quite limited in handling
of parentheses and does not support more complicated transformations
(transforming prefix notation in infix notation or vice versa with
minimal parentheses).
I would like to write
sumFor [0..n] (\i - i^2)
(with sumFor xs f = sum $ map f xs)
which is rendered as
\sum_{i=0}^{n} i^2
or
integrate 1000 (a,b) (\t - f t)
to be rendered as
\int_a^b f(t) \dif t
Neat idea! Can't you do implement this as a DSL?
sumFor x xs f =
\sum_{ ++ x ++ = ++ head xs ++ }^{ ++ last xs ++ }
++ f x
My original idea was to use the formulas in papers both for typesetting
and for unit testing. Thus, when you state that a function fulfills a
law, that it can be automatically tested by QuickCheck, that this at
least true for some instances.
The same would be useful for Haddock documentation. I remember that
someone proposed to permit Haddock to expose the implementation of some
functions as examples or as unit-tests/laws. Now we could extend this
idea to allow Haddock not only to expose the implementation of
functions, but also to tell Haddock how to render its implementation.
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[Haskell-cafe] Additonal types for Foreign.C.Types
Hi, After reading an ISO draft for standard C, I found a few types that could be usefull when binding to libraries (these are from stdint.h): int8_t, uint8_t, int16_t, uint16_t, int32_t, uint32_t, int64_t, uint64_t What about if they were included in the next version of GHC Foreign.C.Types module? For instance, as: CInt8, CUInt8, CInt16 etc. Some libraries (e.g. sqlite) define function parameters that are supposed to always have a given size (e.g., sqlite defines sqlite3_int64). In order to have a portable binding to those libraries, it would be nice to have types in Haskell that also offer that guarantee. There are also a few other nice types, although I'm not sure they belong to standard modules. If they did, however, they could make life easier for those people writing higher level Haskell modules after standard C functions: complex, float complex, double complex (from complex.h) are used in functions like ccos, csin, cexp, csqrt etc. struct lconv (from locale.h) struct tm (from time.h) From wchar.h and wctype.h: mbstate_t, wint_t, wctrans_t, wctype_t. Do you think I could open a ticket for GHC proposing that? Best, Maurício ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell Fest
Just be careful. The judge uses lazy evaluation, so if you get arrested you might spend 20 years in the holding pen. On the bright side, you can pay for stuff whenever you feel like it. 2009/2/9 Lyle Kopnicky li...@qseep.net Looks like a lot of fun! http://www.haskellchamber.com/page6.html ___ 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] evaluation semantics of bind
forwarded: Yes! if no state is passed, the optimization makes sense and the term is not executed, like any lazy evaluation. For example, I used the debugger (that is, without optimizations) to verify it with the Maybe monad: op x= x+x print $ Just (op 1) = \y- return (Just 2) does not evaluate op 1 but print $ Just (op 1) = \y- return y does execute it. The trace of the first: [1 of 1] Compiling Main ( test.hs, interpreted ) Ok, modules loaded: Main. *Main :set stop :list *Main :step main Stopped at test.hs:4:6-43 _result :: IO () = _ 3 4 main= print $ Just (op 1) = \y- return 2 ^^ 5 [test.hs:4:6-43] *Main :step Stopped at test.hs:4:14-43 _result :: Maybe Integer = _ 3 4 main= print $ Just (op 1) = \y- return 2 ^^ 5 [test.hs:4:14-43] *Main :step Stopped at test.hs:4:14-24 _result :: Maybe Integer = _ 3 4 main= print $ Just (op 1) = \y- return 2 ^^^ 5 [test.hs:4:14-24] *Main :step Stopped at test.hs:4:35-43 _result :: Maybe Integer = _ 3 4 main= print $ Just (op 1) = \y- return 2 ^ 5 [test.hs:4:35-43] *Main :step Just 2 But in the second case op is executed: *Main :step main Stopped at test.hs:4:6-43 _result :: IO () = _ 3 4 main= print $ Just (op 1) = \y- return y ^^ 5 [test.hs:4:6-43] *Main :step Stopped at test.hs:4:14-43 _result :: Maybe Integer = _ 3 4 main= print $ Just (op 1) = \y- return y ^^ 5 [test.hs:4:14-43] *Main :step Stopped at test.hs:4:14-24 _result :: Maybe Integer = _ 3 4 main= print $ Just (op 1) = \y- return y ^^^ 5 [test.hs:4:14-24] *Main :step Stopped at test.hs:4:35-43 _result :: Maybe Integer = _ y :: Integer = _ 3 4 main= print $ Just (op 1) = \y- return y ^ 5 [test.hs:4:35-43] *Main :step Just Stopped at test.hs:4:20-23 _result :: Integer = _ 3 4 main= print $ Just (op 1) = \y- return y 5 [test.hs:4:20-23] *Main :step Stopped at test.hs:6:0-8 _result :: Integer = _ 5 6 op x= x+x ^ 7 [test.hs:6:0-8] *Main :step Stopped at test.hs:6:6-8 _result :: Integer = _ x :: Integer = _ 5 6 op x= x+x ^^^ 7 [test.hs:6:6-8] *Main :step Just 2 2009/2/5 Gregg Reynolds d...@mobileink.com- Ocultar texto citado - On Thu, Feb 5, 2009 at 9:27 AM, Bulat Ziganshin bulat.zigans...@gmail.com wrote: Hello Gregg, Thursday, February 5, 2009, 6:20:06 PM, you wrote: An optimizer can see that the result of the first getChar is discarded and replace the entire expression with one getChar without changing the formal semantics. this is prohibited by using pseudo-value of type RealWorld which is passed through entire action stream. actually, order of execution is controlled by dependencies on this values http://haskell.org/haskellwiki/IO_inside Thanks. I actually read that a few weeks ago and forgot all about it. So the gist is that type IO has special magic semantics. Formal, but hidden. Which means monad semantics are built in to the language, at least for that type. The Haskell Report doesn't seem to say anything about this, which seems odd. But then for non-IO monads, the optimization would be allowed, no? Of course; only the IO monad has external world behavior. Thanks, gregg ___ 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] evaluation semantics of bind
On Mon, Feb 9, 2009 at 10:17 PM, Richard O'Keefe o...@cs.otago.ac.nz wrote: On 10 Feb 2009, at 5:07 pm, Gregg Reynolds wrote: Thanks. I see the error of my ways. So, IO expressions must be evaluated if they are in the chain leading to main. We need some standard terminology to distinguish between *evaluating* an expression and *performing* the result of an expression of type IO something. Indeed. Wrote a blog article about this proposing a semiotic approach: http://syntax.wikidot.com/blog:4 An IO expression that is passed to a function at a strict position must be evaluated whether the result is performed or not. An IO expression whose result will be performed must be evaluated before that performance can take place. Is the result of evaluation a thunk/suspension/closer? (Dash it, this really is getting us into White Knight land.) What's White Knight land? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Painting logs to get a coloured tree
2009/2/10 Joachim Breitner m...@joachim-breitner.de: Hi, Am Dienstag, den 10.02.2009, 10:05 +0100 schrieb minh thu: I forgot to mention you can try to tie the knot too, using the result of the processing in the first mapping (and then you don't need the second one)... could you elaborate who to tie that particular knot? I unfortunately, I don't see it. Thanks, Joachim I can post some code later but here is the idea. You conceptually label the tree with Int's. If you go through the tree visiting the node in a specific order, you don't have to actually label it since the label of a node is just its position in the parcour. The goal is to map the tree with some data drawn from an association-list. Again, a straight-forward association is just a plain list indexed by Int's. Thus, when visiting the nodes of the tree, if you have the above-mentionned list, you can use that information when doing the mapping, replacing the data in the node by the data in the list (where the index used for the list is the 'label' of the node). The list is the result of going to the tree too, thus tying the knot. To construct it, you simply make some kind of mapAccum, using [] as the starting value and : (cons) to accumulate the data. To understand this intuitiveley, just note that a three can be flattened into a list. Thus if you want to process the 'association-list' which is represented by a plain list, just zipWith it [0..]. Cheers, Thu ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] evaluation semantics of bind
The result of an evaluation is always in WHNF (weak head normal form). So if it's a function, it's been evaluated to \ x - ..., but no evaluation under lambda. Similarely, if it's a data type it has been evaluated so the outermost form is a constructor, but no evaluation inside the constructor. The terms thunk/suspension/closure usually refer to implementation rather than semantics. But in terms of an implementation, the answer is no. After evaluation you will have none of those as the outmost thing. -- Lennart 2009/2/10 Gregg Reynolds d...@mobileink.com: Is the result of evaluation a thunk/suspension/closer? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: How outdated is Hugs?
John Goerzen wrote: Just to close -- I will point out that ghci doesn't work on many platforms that Hugs does (though ghc does). Hugs is the only interpreter on some of these platforms. I didn't see anyone follow up to this so I'll just mention that nowadays GHCi works wherever GHC works, since 6.10.1. Actually I think most platforms worked with 6.8.1, but 6.10.1 added libffi which meant that GHCi also gets working FFI support on any platform supported by libffi, which is most of them. Cheers, Simon ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: [Haskell] Google Summer of Code 2009
What I would like to see is H.264 video codec in Haskell. H.264/MPEG-4 is getting very popular nowadays and it would be great to have encoder and decoder in haskell. Can use x264 (encoder) and ffmpeg (en/de coder) as a base to start with. Jamie ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Painting logs to get a coloured tree
2009/2/10 minh thu not...@gmail.com: 2009/2/10 Joachim Breitner m...@joachim-breitner.de: Hi, Am Dienstag, den 10.02.2009, 10:05 +0100 schrieb minh thu: I forgot to mention you can try to tie the knot too, using the result of the processing in the first mapping (and then you don't need the second one)... could you elaborate who to tie that particular knot? I unfortunately, I don't see it. Thanks, Joachim I can post some code later but here is the idea. You conceptually label the tree with Int's. If you go through the tree visiting the node in a specific order, you don't have to actually label it since the label of a node is just its position in the parcour. The goal is to map the tree with some data drawn from an association-list. Again, a straight-forward association is just a plain list indexed by Int's. Thus, when visiting the nodes of the tree, if you have the above-mentionned list, you can use that information when doing the mapping, replacing the data in the node by the data in the list (where the index used for the list is the 'label' of the node). The list is the result of going to the tree too, thus tying the knot. To construct it, you simply make some kind of mapAccum, using [] as the starting value and : (cons) to accumulate the data. To understand this intuitiveley, just note that a three can be flattened into a list. Thus if you want to process the 'association-list' which is represented by a plain list, just zipWith it [0..]. So here some code, notice the process function which work on a list of data (drawn from the tree). As said above, it can make use of a [0..] list if the 'tags' or 'names' are needed for processing. Is it applicable to your problem ? -- module Log where data Tree a = Bud | Branch a (Tree a) (Tree a) -- no length here deriving Show mapAcc f acc Bud = (acc, Bud) mapAcc f acc (Branch a l r) = (acc2, Branch a' l' r') where (acc0,a') = f acc a (acc1,l') = mapAcc f acc0 l (acc2,r') = mapAcc f acc1 r tree0 = Bud tree1 = Branch a Bud Bud tree2 = Branch r (Branch s Bud Bud) Bud tree3 = Branch x (Branch y tree1 tree2) Bud process :: [String] - [String] process l = zipWith (\a b - a ++ show b) l [0..] tie tree = tree' where ((acc,q),tree') = mapAcc (\(acc,p) a - ((acc + 1,a:p),r !! acc)) (0,[]) tree r = process (reverse q) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: [Haskell] Google Summer of Code 2009
SNMP would be really cool. So far the best implementation of SNMP I've had the pleasure to work with is part of the Erlang OTP distribution, and being able to compete with Erlang on that level would be really nice. On Tue, Feb 10, 2009 at 7:18 AM, Jamie hask...@datakids.org wrote: What I would like to see is H.264 video codec in Haskell. H.264/MPEG-4 is getting very popular nowadays and it would be great to have encoder and decoder in haskell. Can use x264 (encoder) and ffmpeg (en/de coder) as a base to start with. Jamie ___ 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
[Haskell-cafe] Re: [Haskell] Google Summer of Code 2009
Malcolm.Wallace: Gentle Haskellers, The Google Summer of Code will be running again this year. Once again, haskell.org has the opportunity to bid to become a mentoring organisation. (Although, as always, there is no guarantee of acceptance.) If you have ideas for student projects that you think would benefit the Haskell community, now is the time to start discussing them on mailing lists of your choice. We especially encourage students to communicate with the wider community: if you keep your ideas private, you have a much worse chance of acceptance than if you develop ideas in collaboration with those who will be your customers, end-users, or fellow-developers. This is the open-source world! And I'll just note that since December we've been running a proposal submission site here, where you can vote and comment on ideas, http://www.reddit.com/r/haskell_proposals/top/ A great place to suggest ideas! -- Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Additonal types for Foreign.C.Types
I think you can use Data.Word and Data.Int types for this, that is. Data.Word.Word16 == uint16_t, Data.Word.Word32 == uint32_t, etc. Data.Int.Int16 = int16_t, Data.Int.Int32 = int32_t, etc. There are Foreign.Storable.Storable instances for those. -Ross On Feb 10, 2009, at 6:32 AM, Maurí cio wrote: Hi, After reading an ISO draft for standard C, I found a few types that could be usefull when binding to libraries (these are from stdint.h): int8_t, uint8_t, int16_t, uint16_t, int32_t, uint32_t, int64_t, uint64_t What about if they were included in the next version of GHC Foreign.C.Types module? For instance, as: CInt8, CUInt8, CInt16 etc. Some libraries (e.g. sqlite) define function parameters that are supposed to always have a given size (e.g., sqlite defines sqlite3_int64). In order to have a portable binding to those libraries, it would be nice to have types in Haskell that also offer that guarantee. There are also a few other nice types, although I'm not sure they belong to standard modules. If they did, however, they could make life easier for those people writing higher level Haskell modules after standard C functions: complex, float complex, double complex (from complex.h) are used in functions like ccos, csin, cexp, csqrt etc. struct lconv (from locale.h) struct tm (from time.h) From wchar.h and wctype.h: mbstate_t, wint_t, wctrans_t, wctype_t. Do you think I could open a ticket for GHC proposing that? Best, Maurício ___ 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] The Haskell re-branding exercise
On 7 feb 2009, at 22:40, Don Stewart wrote: bulat.ziganshin: Hello Don, Saturday, February 7, 2009, 8:20:23 PM, you wrote: We need a voting site set up. There was some progress prior to the end of the year. Updates welcome! i think that there are a lot of free voting/survey services available. the last one i went through was LimeSurvey available for any SF project and on separate site too http://apps.sourceforge.net/trac/sitedocs/wiki/Hosted%20Apps https://www.limeservice.com/ Before the new year's break, the progress we made towards deciding on a voting process was, http://groups.google.com/group/fa.haskell/msg/5d0ad1a681b044c7 Eelco implemented a demo condorcet voting system in HAppS. He then asked for help with some decisions: * Limit voting, if so how? Email confirmation, IP based, vote once, once per day? * Maybe don't show the results until the contest is over? Eelco, can we do simple email-based confirm to encourage people to vote only once, and can we keep the results closed until the vote process is over? Yes, sure. I'll try to make some time to finish the implementation, hopefully early next week. In the mean time, if somebody wants to go ahead and implement it (and maybe your own favorite feature as well), feel free to fork from http://github.com/eelco/voting The idea is that you only need to change the HTML to change the things that are voted upon. It might be nice(r) to use JavaScript to load those things. If you want to hack on it and have some questions please email me directly if you want a prompt response ;) -- Regards, Eelco Lempsink PGP.sig Description: This is a digitally signed message part ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Asking the GHC garbage collector to run
Hi all, Is it possible to ask the GHC garbage collector to run ? Something like a collectAllGarbage :: IO() call. Greetings, Mads Lindstrøm ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Asking the GHC garbage collector to run
mads_lindstroem: Hi all, Is it possible to ask the GHC garbage collector to run ? Something like a collectAllGarbage :: IO() call. System.Mem.performGC iirc, Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Why does sleep not work?
The POSIX sleep function is defined as: sleep() makes the current process sleep until seconds seconds have elapsed or a signal arrives which is not ignored. Sounds like a signal is arriving that is interrupting the sleep. -Corey O'Connor 2009/2/9 John Ky newho...@gmail.com: Hi Peter, Source code: import System.IO import System.Posix main = do putStrLn Waiting for 5 seconds. sleep 5 -- doesn't sleep at all putStrLn Done. OS: Mac OS X 10.5 Compile command: ghc --threaded testsleep.hs If I remove --threaded, then it does sleep. Thanks, -John On Tue, Feb 10, 2009 at 8:59 AM, Peter Verswyvelen bugf...@gmail.com wrote: Hi John, Which sleep are you using? From which module? Can you show the full source with import statements? Cheers, Peter 2009/2/9 John Ky newho...@gmail.com Hi Haskell Cafe, I wrote very short program to sleep for 5 seconds compiled with the -threaded option in ghc on the Mac OS X 1.5. I am finding that using the sleep function doesn't sleep at all, whereas using threadDelay does: main = do putStrLn Waiting for 5 seconds. threadDelay 500 -- works putStrLn Done. main = do putStrLn Waiting for 5 seconds. sleep 5 -- doesn't sleep at all putStrLn Done. Anybody know what's happening? Thanks -John ___ 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 ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Painting logs to get a coloured tree
Hi, Am Dienstag, den 10.02.2009, 11:59 +0100 schrieb Heinrich Apfelmus: However, I would be surprised if someAlgorithm could not be formulated directly on the tree or at least satisfies a few invariants like for example map fst . someAlgorithm = map snd Also, how does cutTreeApart arrange the list? The idea is that most of the tree structure survives in the list and can be reconstructed. Probably not. My algorithm calculates the amount of light that shines through the branches, and the amount of light cought by the branches (seeing branches as approximations for leaves here :-)). The algorithm works by taking the list of branches (represented by their start and end point), projects them along the direction of light, creates a list of start and endpoints, sorts them (to be able to sweep the line somewhat efficiently) and adds the projections of all intersections of branches. Then it iterates through the intervals on this line, gets the list of branches that are hit by this interval, sorts them by hights and adds, from top to bottom, the appropriate, decreasing portion of the light that comes in this interval. In this process, the branches are sorted around quite a bit, and I assume it would be hard to preserve the structure. If you want to see code (not sure though if you really want to see that code :-)), it’s in http://git.nomeata.de/?p=L-seed.git;a=blob;f=src/Lseed/Geometry.hs Lines 74-142. Greetings, Joachim -- Joachim Breitner e-Mail: m...@joachim-breitner.de Homepage: http://www.joachim-breitner.de ICQ#: 74513189 Jabber-ID: nome...@joachim-breitner.de signature.asc Description: Dies ist ein digital signierter Nachrichtenteil ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Changing version numbering schemes for HackageDB packages?
I released a new version of data-spacepart that resolved some of the issues with the previous release. One issue I had was the previous release used the version numbering scheme I use at work: [date].[release] Which does not appear to work as well as the traditional X.Y.Z release numbering scheme with Cabal. As part of the new release I changed the version numbering scheme. An *obviously* bad idea if I thought it through. Any [date].[release] style version number is greater than a X.Y.Z version number until X gets rather large. So what to do? Continue using the [date].[release] version numbering scheme? Or is there a way to coax HackageDB to ignore the old release? EG: The new release is: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/data-spacepart-0.1.1 The old release is: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/data-spacepart-20090126.0 The latest release according to HackageDB is: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/data-spacepart Which points to the old release. Cheers, -Corey O'Connor ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Painting logs to get a coloured tree
Hi, Am Dienstag, den 10.02.2009, 16:36 +0100 schrieb minh thu: So here some code, notice the process function which work on a list of data (drawn from the tree). As said above, it can make use of a [0..] list if the 'tags' or 'names' are needed for processing. Is it applicable to your problem ? -- module Log where data Tree a = Bud | Branch a (Tree a) (Tree a) -- no length here deriving Show mapAcc f acc Bud = (acc, Bud) mapAcc f acc (Branch a l r) = (acc2, Branch a' l' r') where (acc0,a') = f acc a (acc1,l') = mapAcc f acc0 l (acc2,r') = mapAcc f acc1 r tree0 = Bud tree1 = Branch a Bud Bud tree2 = Branch r (Branch s Bud Bud) Bud tree3 = Branch x (Branch y tree1 tree2) Bud process :: [String] - [String] process l = zipWith (\a b - a ++ show b) l [0..] tie tree = tree' where ((acc,q),tree') = mapAcc (\(acc,p) a - ((acc + 1,a:p),r !! acc)) (0,[]) tree r = process (reverse q) thanks for your work. It doesn’t fit directly (if the process operation reorders the elements of the list, it fails). But if I first number them, and later sort them again, or use lookup instead of !!, it would work. But the knot-tying (and thus the single traversal of the tree) is a very neat idea. Greetings, Joachim -- Joachim Breitner e-Mail: m...@joachim-breitner.de Homepage: http://www.joachim-breitner.de ICQ#: 74513189 Jabber-ID: nome...@joachim-breitner.de signature.asc Description: Dies ist ein digital signierter Nachrichtenteil ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Why does sleep not work?
Not to say the issue shouldn't be tracked down, but shouldn't a more portable function be used anyway? untested example: maxBoundMicroSecInSec =(maxBound `div` 10^6) threadDelaySec :: Int - IO () threadDelaySec s | s maxBoundMicroSecInSec = threadDelay (maxBoundMicroSecInSec * 10^6) threadDelaySec (s - maxBoundMicroSecInSec) | otherwise = threadDelay (s * 10^6) On Tue, Feb 10, 2009 at 5:57 PM, Corey O'Connor coreyocon...@gmail.com wrote: The POSIX sleep function is defined as: sleep() makes the current process sleep until seconds seconds have elapsed or a signal arrives which is not ignored. Sounds like a signal is arriving that is interrupting the sleep. -Corey O'Connor 2009/2/9 John Ky newho...@gmail.com: Hi Peter, Source code: import System.IO import System.Posix main = do putStrLn Waiting for 5 seconds. sleep 5 -- doesn't sleep at all putStrLn Done. OS: Mac OS X 10.5 Compile command: ghc --threaded testsleep.hs If I remove --threaded, then it does sleep. Thanks, -John On Tue, Feb 10, 2009 at 8:59 AM, Peter Verswyvelen bugf...@gmail.com wrote: Hi John, Which sleep are you using? From which module? Can you show the full source with import statements? Cheers, Peter 2009/2/9 John Ky newho...@gmail.com Hi Haskell Cafe, I wrote very short program to sleep for 5 seconds compiled with the -threaded option in ghc on the Mac OS X 1.5. I am finding that using the sleep function doesn't sleep at all, whereas using threadDelay does: main = do putStrLn Waiting for 5 seconds. threadDelay 500 -- works putStrLn Done. main = do putStrLn Waiting for 5 seconds. sleep 5 -- doesn't sleep at all putStrLn Done. Anybody know what's happening? Thanks -John ___ 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 ___ 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: Additonal types for Foreign.C.Types
The FFI spec says (at http://www.cse.unsw.edu.au/~chak/haskell/ffi/ffi/ffise3.html#x6-120003.2) : The argument types at[i] produced by fatype must be marshallable foreign types; that is, each ati is either (1) a basic foreign type or (2) a type synonym or renamed datatype of a marshallable foreign type. Moreover, the result type rt produced by frtype must be a marshallable foreign result type; that is, it is either a marshallable foreign type, the type (), or a type matching Prelude.IO t, where t is a marshallable foreign type or (). Earlier it defines the basic foreign types: The following types constitute the set of basic foreign types: * Char, Int, Double, Float, and Bool as exported by the Haskell 98 Prelude as well as * Int8, Int16, Int32, Int64, Word8, Word16, Word32, Word64, Ptr a, FunPtr a, and StablePtr a, for any type a, as exported by Foreign (Section 5.1). So, that list of types, or any type synonym. -Ross On Feb 10, 2009, at 3:56 PM, Maurí cio wrote: Yes, I can. Thanks. Just forget my idea, with this I can provide all those types in a library. I'm confused. When is it possible to use a type as a parameter to a foreign function call? My first guess was that I had to provide an instance for class Storable, but after I tried writing a complex-like type that way GHC told me my type was unaceptable. So I thought only types allowed by the compiler (including forall a. Ptr a) could be used that way. What is the rule? I've read all of FFI report and found nothing. Did I miss something? How can I make a type of mine acceptable? Why are Data.Int acceptable, and how could I know that? Thanks, Maurício I think you can use Data.Word and Data.Int types for this, that is. (...) After reading an ISO draft for standard C, I found a few types that could be usefull when binding to libraries (these are from stdint.h): int8_t, uint8_t, int16_t, uint16_t, int32_t, uint32_t, int64_t, uint64_t (...) ___ 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] Changing version numbering schemes for HackageDB packages?
* Corey O'Connor coreyocon...@gmail.com [2009-02-10 10:21:54-0800] I released a new version of data-spacepart that resolved some of the issues with the previous release. One issue I had was the previous release used the version numbering scheme I use at work: [date].[release] Which does not appear to work as well as the traditional X.Y.Z release numbering scheme with Cabal. As part of the new release I changed the version numbering scheme. An *obviously* bad idea if I thought it through. Any [date].[release] style version number is greater than a X.Y.Z version number until X gets rather large. So what to do? Continue using the [date].[release] version numbering scheme? Or is there a way to coax HackageDB to ignore the old release? From haxr changelog: Sun Feb 11 11:43:15 EET 2007 bj...@bringert.net * Changed haxr version number to 3000.0.0 to avoid ordering problems with old date-based version numbers. -- Roman I. Cheplyaka :: http://ro-che.info/ Don't let school get in the way of your education. - Mark Twain ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: [Haskell] Google Summer of Code 2009
On Tuesday 10 February 2009 07:18:00 am Jamie wrote: What I would like to see is H.264 video codec in Haskell. H.264/MPEG-4 is getting very popular nowadays and it would be great to have encoder and decoder in haskell. Can use x264 (encoder) and ffmpeg (en/de coder) as a base to start with. Jamie GSoC is run out of the US, where software patents would prevent a student from taking this task. -- Conrad Meyer kon...@tylerc.org ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: How outdated is Hugs?
On Tuesday 10 February 2009 06:41:54 am Simon Marlow wrote: John Goerzen wrote: Just to close -- I will point out that ghci doesn't work on many platforms that Hugs does (though ghc does). Hugs is the only interpreter on some of these platforms. I didn't see anyone follow up to this so I'll just mention that nowadays GHCi works wherever GHC works, since 6.10.1. Actually I think most platforms worked with 6.8.1, but 6.10.1 added libffi which meant that GHCi also gets working FFI support on any platform supported by libffi, which is most of them. Cheers, Simon Counterexample: GHC 6.10.1 works on linux/ppc, GHCi 6.10.1 does not. (6.8.3 worked, though.) Regards, -- Conrad Meyer kon...@tylerc.org ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Why does sleep not work?
John Ky ha scritto:
Hi Haskell Cafe,
I wrote very short program to sleep for 5 seconds compiled with the
-threaded option in ghc on the Mac OS X 1.5.
I am finding that using the sleep function doesn't sleep at all, whereas
using threadDelay does:
[...]
main = do
putStrLn Waiting for 5 seconds.
sleep 5 -- doesn't sleep at all
putStrLn Done.
Anybody know what's happening?
Here is a syscal trace, on Linux:
http://hpaste.org/fastcgi/hpaste.fcgi/view?id=1332#a1332
The interesting part:
write(1, Waiting for 5 seconds.\n..., 23) = 23
rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0
rt_sigaction(SIGCHLD, NULL, {SIG_DFL}, 8) = 0
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
nanosleep({5, 0}, 0xbf85f5cc) = ? ERESTART_RESTARTBLOCK (To be
restarted)
--- SIGVTALRM (Virtual timer expired) @ 0 (0) ---
sigreturn() = ? (mask now [])
write(1, 5\n..., 2) = 2
So, it seems nanosleep get interruped by a signal.
Manlio Perillo
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[Haskell-cafe] Re: Additonal types for Foreign.C.Types
The FFI spec says (at http://www.cse.unsw.edu.au/~chak/haskell/ffi/ffi/ffise3.html#x6-120003.2): There I see: --- Foreign types are produced according to the following grammar: ftype -- frtype | fatype - ftype frtype -- fatype | () fatype -- qtycon atype[1] ... atype[k] (k 0) --- I can't understand the qtycon atype[1]... line. I did search haskell 98 report syntax reference, and saw how qtycon and tycon are defined, but I could not understand how they are used here. Thanks for your help, Maurício ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Why does sleep not work?
On Tue, 2009-02-10 at 09:57 -0800, Corey O'Connor wrote: The POSIX sleep function is defined as: sleep() makes the current process sleep until seconds seconds have elapsed or a signal arrives which is not ignored. Sounds like a signal is arriving that is interrupting the sleep. -Corey O'Connor I tested this when testing the original code; sleep reports that the signal received is 5 (SIGTRAP). However, the following code does not work: import System.Posix main = do putStrLn Waiting for 5 seconds. print sigTRAP blockSignals $ addSignal sigTRAP emptySignalSet signal - sleep 5 print signal putStrLn Done. This, on the other (strange) hand, does: import System.Posix main = do putStrLn Waiting for 5 seconds. blockSignals fullSignalSet signal - sleep 5 print signal putStrLn Done. - George signature.asc Description: This is a digitally signed message part ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: Additonal types for Foreign.C.Types
fatype is the function argument type. atype[i] are type arguments. qtycon is a qualified (e.g. possibly with module prefix) type constructor, e.g. Just So, for example if you have: foreign import ccall string.h strlen cstrlen :: Ptr CChar - IO CSize fatype - ftype :: ftype fatype :: fatype qtycon Ptr atype1 CChar fatype :: frtype qtycon IO atype1 CSize (I struggled a bit with finding a good way to communicate the productions chosen, so bear with me) Make sense? -Ross On Feb 10, 2009, at 6:13 PM, Maurí cio wrote: The FFI spec says (at http://www.cse.unsw.edu.au/~chak/haskell/ffi/ffi/ffise3.html#x6-120003.2) : There I see: --- Foreign types are produced according to the following grammar: ftype -- frtype | fatype - ftype frtype -- fatype | () fatype -- qtycon atype[1] ... atype[k] (k 0) --- I can't understand the qtycon atype[1]... line. I did search haskell 98 report syntax reference, and saw how qtycon and tycon are defined, but I could not understand how they are used here. Thanks for your help, Maurício ___ 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] Why does sleep not work?
On Wed, 2009-02-11 at 00:05 +0100, Manlio Perillo wrote:
John Ky ha scritto:
Hi Haskell Cafe,
I wrote very short program to sleep for 5 seconds compiled with the
-threaded option in ghc on the Mac OS X 1.5.
I am finding that using the sleep function doesn't sleep at all, whereas
using threadDelay does:
[...]
main = do
putStrLn Waiting for 5 seconds.
sleep 5 -- doesn't sleep at all
putStrLn Done.
Anybody know what's happening?
Here is a syscal trace, on Linux:
http://hpaste.org/fastcgi/hpaste.fcgi/view?id=1332#a1332
The interesting part:
write(1, Waiting for 5 seconds.\n..., 23) = 23
rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0
rt_sigaction(SIGCHLD, NULL, {SIG_DFL}, 8) = 0
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
nanosleep({5, 0}, 0xbf85f5cc) = ? ERESTART_RESTARTBLOCK (To be
restarted)
--- SIGVTALRM (Virtual timer expired) @ 0 (0) ---
sigreturn() = ? (mask now [])
write(1, 5\n..., 2) = 2
So, it seems nanosleep get interruped by a signal.
This works:
import System.Posix
main = do
putStrLn Waiting for 5 seconds.
blockSignals $ addSignal sigVTALRM emptySignalSet
sleep 5
putStrLn Done.
So (see my earlier email) `sleep` is lying about what interrupts it :)
- George
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Re: [Haskell-cafe] Why does sleep not work?
2009/2/10 George Pollard por...@porg.es: import System.Posix main = do putStrLn Waiting for 5 seconds. blockSignals $ addSignal sigVTALRM emptySignalSet sleep 5 putStrLn Done. Huh! Does the GHC runtime uses this signal? Perhaps for scheduling? Cheers, -Corey O'Connor ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] ANN: Bug fix to regex-tdfa, new version 0.97.3
To Haskell and Libraries and Haskell-Cafe, Whilst improving regex-tdfa I have run across new bugs. Some patterns were getting compiled wrong and others were affected by an execution bug. As this package has actual users, I wanted to make sure they get these fixes immediately. Three Cheers For QuickCheck! The new version is 0.97.3 at http://hackage.haskell.org/cgi-bin/hackage-scripts/package/regex-tdfa And this version passes all the unit tests I have, including coverage for the new bugs. This is no warranty that regex-tdfa is bug free, since I made that same claim last release. For instance: I suspect 0.97.3 may be buggy if used in the optional left-associative mode. The new improved version of regex-tdfa is still a long way off. Cheers, Chris Kuklewicz ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Why does sleep not work?
Also attached is a diff for strace between non-threaded and threaded.
execve(./sleep, [./sleep], [/* 38 vars */]) = 0
execve(./sleep, [./sleep], [/* 38 vars */]) = 0
brk(0) = 0x83c2000 | brk(0)
= 0x8ff
access(/etc/ld.so.nohwcap, F_OK) = -1 ENOENT (No such
access(/etc/ld.so.nohwcap, F_OK) = -1 ENOENT (No such
mmap2(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONY | mmap2(NULL,
8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONY
access(/etc/ld.so.preload, R_OK) = -1 ENOENT (No such
access(/etc/ld.so.preload, R_OK) = -1 ENOENT (No such
open(/etc/ld.so.cache, O_RDONLY) = 3
open(/etc/ld.so.cache, O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=68273, ...}) = 0 fstat64(3,
{st_mode=S_IFREG|0644, st_size=68273, ...}) = 0
mmap2(NULL, 68273, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb801b000 | mmap2(NULL,
68273, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb7f8d000
close(3)= 0 close(3)
= 0
access(/etc/ld.so.nohwcap, F_OK) = -1 ENOENT (No such
access(/etc/ld.so.nohwcap, F_OK) = -1 ENOENT (No such
open(/lib/tls/i686/cmov/libutil.so.1, O_RDONLY) = 3
open(/lib/tls/i686/cmov/libutil.so.1, O_RDONLY) = 3
read(3, \177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\340\ read(3,
\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\340\
fstat64(3, {st_mode=S_IFREG|0644, st_size=9688, ...}) = 0 fstat64(3,
{st_mode=S_IFREG|0644, st_size=9688, ...}) = 0
mmap2(NULL, 12424, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYW | mmap2(NULL,
12424, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYW
mmap2(0xb8019000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP |
mmap2(0xb7f8b000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP
close(3)= 0 close(3)
= 0
access(/etc/ld.so.nohwcap, F_OK) = -1 ENOENT (No such
access(/etc/ld.so.nohwcap, F_OK) = -1 ENOENT (No such
open(/lib/tls/i686/cmov/libdl.so.2, O_RDONLY) = 3
open(/lib/tls/i686/cmov/libdl.so.2, O_RDONLY) = 3
read(3, \177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0 \n\0 read(3,
\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0 \n\0
fstat64(3, {st_mode=S_IFREG|0644, st_size=9676, ...}) = 0 fstat64(3,
{st_mode=S_IFREG|0644, st_size=9676, ...}) = 0
mmap2(NULL, 12408, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYW | mmap2(NULL,
12408, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYW
mmap2(0xb8015000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP |
mmap2(0xb7f87000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP
close(3)= 0 close(3)
= 0
access(/etc/ld.so.nohwcap, F_OK) = -1 ENOENT (No such
access(/etc/ld.so.nohwcap, F_OK) = -1 ENOENT (No such
open(/lib/tls/i686/cmov/libm.so.6, O_RDONLY) = 3
open(/lib/tls/i686/cmov/libm.so.6, O_RDONLY) = 3
read(3, \177elf\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\...@4\0\ read(3,
\177elf\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\...@4\0\
fstat64(3, {st_mode=S_IFREG|0644, st_size=149332, ...}) = 0 fstat64(3,
{st_mode=S_IFREG|0644, st_size=149332, ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONY | mmap2(NULL,
4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONY
mmap2(NULL, 151680, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENY | mmap2(NULL,
151680, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENY
mmap2(0xb801, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP |
mmap2(0xb7f82000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP
close(3)= 0 close(3)
= 0
access(/etc/ld.so.nohwcap, F_OK) = -1 ENOENT (No such
access(/etc/ld.so.nohwcap, F_OK) = -1 ENOENT (No such
open(/usr/lib/libgmp.so.3, O_RDONLY) = 3
open(/usr/lib/libgmp.so.3, O_RDONLY) = 3
read(3, \177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\200\ read(3,
\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\200\
fstat64(3, {st_mode=S_IFREG|0644, st_size=284176, ...}) = 0 fstat64(3,
{st_mode=S_IFREG|0644, st_size=284176, ...}) = 0
mmap2(NULL, 287052, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENY | mmap2(NULL,
287052, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENY
mmap2(0xb7fea000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP |
mmap2(0xb7f5c000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP
close(3)= 0 close(3)
= 0
access(/etc/ld.so.nohwcap, F_OK) = -1 ENOENT (No such
access(/etc/ld.so.nohwcap, F_OK) = -1 ENOENT (No such
open(/lib/tls/i686/cmov/librt.so.1, O_RDONLY) = 3
open(/lib/tls/i686/cmov/librt.so.1, O_RDONLY) = 3
read(3, \177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0`\31\ read(3,
Re: [Haskell-cafe] Why does sleep not work?
Corey O'Connor ha scritto: 2009/2/10 George Pollard por...@porg.es: import System.Posix main = do putStrLn Waiting for 5 seconds. blockSignals $ addSignal sigVTALRM emptySignalSet sleep 5 putStrLn Done. Huh! Does the GHC runtime uses this signal? Perhaps for scheduling? Right. It is used for scheduling, as far as I understand. So blocking it is a bad idea (unless you block it in a thread other than the main thread, IMO). Cheers, -Corey O'Connor Regards Manlio ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: [Haskell] Google Summer of Code 2009
I would love a mentor to help me with a Haskell binding to libnova. This is part of a larger project I have in mind, but the libnova binding seems like the first step. I don't expect this to be picked as an official GSoC, but this seemed like a good time to look for a mentor for this project. Michael Litchard On Tue, Feb 10, 2009 at 6:26 AM, Malcolm Wallace malcolm.wall...@cs.york.ac.uk wrote: Gentle Haskellers, The Google Summer of Code will be running again this year. Once again, haskell.org has the opportunity to bid to become a mentoring organisation. (Although, as always, there is no guarantee of acceptance.) If you have ideas for student projects that you think would benefit the Haskell community, now is the time to start discussing them on mailing lists of your choice. We especially encourage students to communicate with the wider community: if you keep your ideas private, you have a much worse chance of acceptance than if you develop ideas in collaboration with those who will be your customers, end-users, or fellow-developers. This is the open-source world! The timeline is that Haskell.org will apply for GSoC membership between 9-13 March, and if we are successful, students can submit applications between 23 March - 3 April. If you wish to help publicise GSoC amongst students, there are official posters/fliers available (not specific to haskell.org): http://code.google.com/p/google-summer-of-code/wiki/GsocFlyers Regards, Malcolm ___ Haskell mailing list hask...@haskell.org http://www.haskell.org/mailman/listinfo/haskell ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] evaluation semantics of bind
On 11 Feb 2009, at 2:22 am, Gregg Reynolds wrote:
Is the result of evaluation a thunk/suspension/closer?
As T. S. Eliot wrote,
Teach us to care and not to care
Teach us to sit still.
There are some things it is better not to care about
and this is one of them.
(Dash it, this really is getting us into White Knight land.)
What's White Knight land?
From Alice in Wonderland.
``You are sad,'' the Knight said in an anxious tone:
``let me sing you a song to comfort you.''
``Is it very long?'' Alice asked,
for she had heard a good deal of poetry that day.
``It's long,'' said the Knight,
``but it's very, {\it very} beautiful.
Everybody that hears me sing it---either
it brings tears to their eyes, or else---''
``Or else what?'' said Alice,
for the Knight had made a sudden pause.
``Or else it doesn't, you know.
The name of the song is called {\it `Haddocks' Eyes.'\/}{}''
``Oh, that's the name of the song, is it?''
Alice said, trying to feel interested.
``No, you don't understand,'' the Knight said,
looking a little vexed.
``That's what the name is {\it called}.
The name really {\it is `The Aged Aged Man.'\/}{}''
``Then I ought to have said, `That's what the {\it song}
is called?'' Alice corrected herself.
``No, you oughtn't: that's quite another thing!
The {\it song} is called {\it `Ways and Means'\/}:
but that's only what it's {\it called}, you know.''
``Well, what {\it is} the song, then?'' said Alice,
who was by this time completely bewildered.
``I was coming to that,'' the Knight said.
``The song really {\it is `A-sitting On a Gate'\/}:
and the tune's my own invention.''
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Re: [Haskell-cafe] Why does sleep not work?
George Pollard ha scritto: [...] So, it seems nanosleep get interruped by a signal. This works: import System.Posix main = do putStrLn Waiting for 5 seconds. blockSignals $ addSignal sigVTALRM emptySignalSet sleep 5 putStrLn Done. So (see my earlier email) `sleep` is lying about what interrupts it :) - George A possibly better solution is: sleep' :: Int - IO Int sleep' n = do n' - sleep n if n' == 0 then return 0 else sleep' n' From the trace, I see that nanosleep is being called 17 times here. Another solution is to set RTS flag: ./bug_sleep +RTS -V0 -RTS What strange is that the timer is created in non threaded RTS, too, but sleep is interrupted only with the threaded RTS. This may be caused by an incorrect execution of a foreign function marked safe. Regards Manlio ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Monad explanation
Richard O'Keefe wrote: Gregg Reynolds wrote: Sure, you can treat a morphism as an object, but only by moving to a higher (or different) level of abstraction. False as a generalisation about mathematics. False about functional programming languages, the very essence of which is treating functions (morphisms) as values (objects) exactly like any other values. That doesn't erase the difference between object and morphism. There is no intrinsic difference between objects and morphisms. It's what you DO with something that makes it an object or a morphism (or both). This is way confusing. Composer (Haskell program) writes score (computes getChar). Performer (Haskell environment) sings score (performs Gamaliel). Sound happens (a character is read). +1. The only difference between objects and morphisms is in the decision by some supreme entity (human reader, Haskell runtime) to treat them differently. There is nothing different between them other than our decisions to treat them differently. As for the concrete example about 3, I define: let 3 = \f x - f(f(f x)) which is as valid as any other definition. Oh noes, you say, it's a function and therefore a morphism. And certainly it is. However, it's perfectly fine to treat that as a value and define a real function like addition: let m + n = \f x - m f (n f x) When people see something like 1 + 2 + 3 they choose to think of 1, 2, and 3 as objects and choose to think of (+) and (+) as morphisms, but who cares? Any datum can be encoded as a function, the execution of which enacts the existence of the object the function denotes. And, in functional languages, functions can be passed around and clubbed over the head just like every other value. And therein lies the rub: the execution of which enacts the existence of the object the function denotes. The only thing that distinguishes objects and morphisms is the decision by some supreme entity to treat them that way. Just as you once said that values don't concatenate, so neither do functions apply. The application of functions can only be observed by some evaluator for the structure generated by application. Application itself has no semantics, it just builds ASTs and uninterpreted terms; only our choice to evaluate ASTs and terms gives them meaning. -- Live well, ~wren ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ANN: convertible (first release)
Hello,
it is a real code snippet, but I failed to include the necessary pragma (which
is:
{-# OPTIONS_GHC -fglasgow-exts #-}
or
{-# OPTIONS_GHC -XMagicHash #-}
at the beginning of the file).
the # suffix is for unboxed types:
http://www.haskell.org/ghc/docs/latest/html/users_guide/primitives.html
http://www.haskell.org/ghc/docs/latest/html/users_guide/syntax-extns.html#magic-hash
Greetings,
Daniel
On Wednesday 11 February 2009 00:19:56 Dylan Tisdall wrote:
Maybe I'm just a noob falling for someone's joke here, but I can't
make that sample, or anything else I tried with # on the end of
names, to compile with ghci. In the example below, I get a parse error
at the line defining d2f. Is this a real code snippet?
Cheers,
Dylan
On Feb 10, 2009, at 2:46 AM, Daniel Schüssler wrote:
Hi,
On Wednesday 28 January 2009 04:30:07 John Goerzen wrote:
On Tue, Jan 27, 2009 at 09:41:30PM -0500, wren ng thornton wrote:
I once again point out that realToFrac is *wrong* for converting
from
Float or Double.
realToFrac (1/0::Float) ::Double
3.402823669209385e38
Yes, I understand what you are saying and agree with you. But there
is nothing better in the standard library
don't know whether you consider GHC as standard library, but if you
do...:
import GHC.Types
import GHC.Prim
-- | Double to Float
d2f (D# d) = F# (double2Float# d)
-- | Float to Double
f2d (F# f) = D# (float2Double# f)
ghci f2d (1/0)
Infinity
it :: Double
:)
--
Daniel
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[Haskell-cafe] Re: Additonal types for Foreign.C.Types
Sure it does! Thanks. (...)So, for example if you have: foreign import ccall string.h strlen cstrlen :: Ptr CChar - IO CSize fatype - ftype :: ftype fatype :: fatype qtycon Ptr atype1 CChar fatype :: frtype qtycon IO atype1 CSize (I struggled a bit with finding a good way to communicate the productions chosen, so bear with me) Make sense? The FFI spec says (at http://www.cse.unsw.edu.au/~chak/haskell/ffi/ffi/ffise3.html#x6-120003.2): There I see: --- (...) I can't understand the qtycon atype[1]... line. (...) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Painting logs to get a coloured tree
minh thu wrote: Joachim Breitner: I thought about Zippers, but I understand that they improve _navigating_ in a Tree-like structure, or to refrence _one_ position in a tree. But if I would deconstruct my tree to the list of _all_ locations, with type Loc a = (Tree a, Cxt a) and then run my algorithm that returns [(Loc a, Info)], it's still not clear to me how I can combine all of these locations to get back my original Tree, annotated with the Info returned. I guess I just repeat your last praragraph of your original mail but it seems to me you can mapAccump some 'names' on the tree, process an association list (or an IntMap) of the (name,log) then map the three again using the result. In spirits, it's the same thing than the STRef solution but it seems cleaner to me. It might also be worth looking at Okasaki's algorithm for (breadth-first) numbering of nodes in a tree[1]. Assuming your tree doesn't have interesting invariants to maintain, a similar/inverse algorithm could be used to unfold a list of logs back into a tree. As minh thu says, the numbering seems like it only needs to be conceptual rather than actual. In which case you should be able to fuse the code that traverses the tree to produce logs and the code that traverses the logs to produce a tree (aka a hylomorphism, if you're familiar). The knot-tying step should only be necessary if constructing the tree from logs requires more information than whatever's local to the log itself. Of course, if global information is necessary then you probably _do_ need to actually label the tree. At least it's cleaner than STRefs since you don't need mutability. [1] http://www.eecs.usma.edu/webs/people/okasaki/pubs.html#icfp00 -- Live well, ~wren ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] evaluation semantics of bind
Alberto G. Corona wrote: forwarded: Yes! if no state is passed, the optimization makes sense and the term is not executed, like any lazy evaluation. For example, I used the debugger (that is, without optimizations) to verify it with the Maybe monad: op x= x+x print $ Just (op 1) = \y- return (Just 2) does not evaluate op 1 Presumably you mean?: print $ Just (op 1) = \y- return 2 but print $ Just (op 1) = \y- return y does execute it. Dashing off towards the White Knight, we should be careful what is said here. If we take only the expression Just (op 1) = \y- return y then evaluating it yields Just (op 1). That is, it only evaluates to WHNF and does not evaluate what's inside. It is only once this value is subsequently handed off to print or some other function, that it may become evaluated. Similarly with the first example as originally written. It so happens that bind is non-strict for the field in Just, so we can discard the op 1. However, according to the semantics we do not evaluate Just 2 either; we only need to evaluate the return which will produce Just and pass the operand down. (Regardless of the fact that the value yielded by applying Just to 2 is Just 2. Expressions and their denotations are different.) -- Live well, ~wren ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: [Haskell] Google Summer of Code 2009
On Tue, 10 Feb 2009, Conrad Meyer wrote: On Tuesday 10 February 2009 07:18:00 am Jamie wrote: What I would like to see is H.264 video codec in Haskell. H.264/MPEG-4 is getting very popular nowadays and it would be great to have encoder and decoder in haskell. Can use x264 (encoder) and ffmpeg (en/de coder) as a base to start with. Jamie GSoC is run out of the US, where software patents would prevent a student from taking this task. via http://www.videolan.org/developers/x264.html x264 is a free library for encoding H264/AVC video streams. The code is written from scratch by Laurent Aimar, Loren Merritt, Eric Petit (OS X), Min Chen (vfw/asm), Justin Clay (vfw), Måns Rullgård, Radek Czyz, Christian Heine (asm), Alex Izvorski, and Alex Wright. It is released under the terms of the GPL license. Seems like it is ok to write H.264 in Haskell and released via GPL license? There is theora.org but H.264 would be ideal. Ditto for H.263. Conrad Meyer kon...@tylerc.org Jamie___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: [Haskell] Google Summer of Code 2009
2009/2/10 Jamie hask...@datakids.org: On Tue, 10 Feb 2009, Conrad Meyer wrote: On Tuesday 10 February 2009 07:18:00 am Jamie wrote: What I would like to see is H.264 video codec in Haskell. H.264/MPEG-4 is getting very popular nowadays and it would be great to have encoder and decoder in haskell. Can use x264 (encoder) and ffmpeg (en/de coder) as a base to start with. Jamie GSoC is run out of the US, where software patents would prevent a student from taking this task. via http://www.videolan.org/developers/x264.html x264 is a free library for encoding H264/AVC video streams. The code is written from scratch by Laurent Aimar, Loren Merritt, Eric Petit (OS X), Min Chen (vfw/asm), Justin Clay (vfw), Måns Rullgård, Radek Czyz, Christian Heine (asm), Alex Izvorski, and Alex Wright. It is released under the terms of the GPL license. Seems like it is ok to write H.264 in Haskell and released via GPL license? There is theora.org but H.264 would be ideal. Ditto for H.263. Conrad Meyer kon...@tylerc.org Jamie Software patent issues are entirely orthogonal to the copyright issues of who wrote what under which license. That's why software patents suck so very hard. See https://secure.wikimedia.org/wikipedia/en/wiki/Software_patent#Free_and_open_source_software https://secure.wikimedia.org/wikipedia/en/wiki/Software_patents_and_free_software -- gwern signature.asc Description: OpenPGP digital signature ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: [Haskell] Google Summer of Code 2009
(The following is a quasi essay/list of past Summer of Code projects;
my hope is to guide thinking about what Summer of Code projects would
be good to pick, and more specifically what should be avoided.
If you're in a hurry, my conclusions are at the bottom.
The whole thing is written in Markdown; for best results pass it
through Pandoc or view it via your friendly local Gitit wiki.)
# Summer of Code
As part of Google's [Summer of
code](http://en.wikipedia.org/wiki/Google_Summer_of_Code)[](http://code.google.com/soc/)
program, Google sponsors 5-10 [projects for
Haskell](http://hackage.haskell.org/trac/summer-of-code/).
The Haskell Summer of Codes have often produced excellent results, but
how excellent is excellent? Are there any features or commonalities
between successful projects or unsuccessful ones?
(This questions are particularly important as SoC 2009 isn't too far
away; yet we don't have even a general sense of where we are.)
## Example retrospective: Debian
An energetic blogger Debian developer has produced
[a](http://www.milliways.fr/2009/01/20/debian-2008-where-now-1/)
[three](http://www.milliways.fr/2009/01/28/debian-2008-where-now-2/)
[part](http://www.milliways.fr/2009/02/02/debian-2008-where-now-3/)
series on the many Debian-related Summer of Code projects.
The results are interesting: some projects were a failure and the
relevant student drifted away and had little to do with Debian again;
and some were great successes. I don't discern any particular lessons
there, except perhaps one against hubris or filling unclear needs.
Let's see whether that holds true of Haskell.
### Haskell retrospective
Haskell wasn't part of the first Summer of Code in 2005, but it was
accepted for 2006. We start there.
2006
The 2006 [homepage](http://hackage.haskell.org/trac/summer-of-code/wiki/SoC2006)
lists the following projects:
- Fast Mutable Collection Types for Haskell
Caio Marcelo de Oliveira Filho, mentored by Audrey Tang
This ultimately resulted in the
[HsJudy](http://hackage.haskell.org/cgi-bin/hackage-scripts/package/HsJudy)
library ('fast mutable collection' here meaning 'array'; see the
[application](http://darcs.haskell.org/judy/SOC_APP.txt)). HsJudy was
apparently used in Pugs at one time, but no more. Thus, I judge this
to have been **unsuccessful**.
- Port Haddock to use GHC
David Waern, mentored by Simon Marlow
**Successful**. Haddock has used the GHC API ever since.[^complaints]
- A model for client-side scripts with HSP
Joel Björnson, mentored by Niklas Broberg
Was initially unsuccessful, but seems to've been picked up again.
So I give this a tentative **successful**
- GHCi based debugger for Haskell
José Iborra López, mentored by David Himmelstrup
**Successful**. The GHCi debugger was accepted into GHC HEAD, and
by now is in production use,
- HaskellNet
Jun Mukai, mentored by Shae Erisson
**Unsuccessful**. HaskellNet is dead, and nothing of it has
propagated elsewhere. (I'm not entirely sure what happened with the
HaskellNet code - I know of
[two](http://darcs.haskell.org/SoC/haskellnet/)
[repos](http://stuff.mit.edu/afs/sipb/project/suez/src/haskell/haskellnet/),
but that's about it.) Shae tells me that this poor uptake is probably
due to a lack of advertising, and not any actual defect in the
HaskellNet code.
- Language.C - a C parser written in Haskell
Marc van Woerkom, mentored by Manuel Chakravarty
**Failure**. According to [Don Stewart's
outline](http://www.haskell.org/pipermail/haskell-cafe/2007-February/022509.html)
of the 2006 SoC, this project was not completed.
- Implement a better type checker for Yhc
Leon P Smith, mentored by Malcolm Wallace
**Failure**. See Language.C
- Thin out cabal-get and integrate in GHC
Paolo Martini, mentored by Isaac Jones
**Successful**. Code is in Cabal, which we all know and love.
- Unicode ByteString, Data.Rope, Parsec for generic strings
Spencer Janssen, mentored by Don Stewart
**Successful**. (Again, per Don.)
4 successful; 2 unsuccessful; and 2 failures.
2007
The [2007 homepage](http://hackage.haskell.org/trac/summer-of-code/wiki/SoC2007)
- Darcs conflict handling
Jason Dagit, mentored by David Roundy
**Successful**. The work was successful in almost completely
getting rid of the exponential conflict bug, and has been in the
regular releases of Darcs 2.x for some time now.
- Automated building of packages and generation of Haddock documentation
Sascha Böhme, mentored by Ross Paterson
**Successful**. The auto build and doc generation are
long-standing and very useful parts of Hackage.
- Rewrite the typechecker for YHC and nhc98
Mathieu Boespflug, mentored by Malcolm Wallace
Unknown.
- Cabal Configurations
Thomas Schilling, mentored by Michael Isaac Jones
**Successful**. Cabal configurations have been around for a while
and are very useful for enabling/disabling things
- Update
[Haskell-cafe] Gtk2HS 0.10.0 Released
Hi everyone, Oh, dear... it seems I've forgotten how to spell cafe, and sent this message to haskell-c...@haskell.org the first time around. I resent it to all the lists again (just to make sure everyone interested receives it), so I apologize for any duplicated messages you might have received. In any case... I'd like to release the announcement of Gtk2HS 0.10.0. A lot of new stuff has gone into this release, including: - Support for GHC 6.10 - Bindings to GIO and GtkSourceView-2.0 - Full switch to the new model-view implementation using a Haskell model - Support for many more model-based widgets such as IconView and an updated binding for ComboBox - Full Drag-and-Drop support - Better support for Attributes in Pango - Replaced Event for EventM monad, thereby improving efficiency and convenience - Functions for interaction between Cairo and Pixbuf drawing - Lots of bug fixes, code cleanups, and portability improvements With this release, the bindings to GnomeVFS and GtkSourceView-1.0 have been deprecated. The TreeList modules have been deprecated from the Gtk+ bindings. Source and Win32 binaries are available at: https://sourceforge.net/project/showfiles.php?group_id=49207package_id=42440release_id=659598 Thanks to everyone who submitted bug fixes and features this time around! Thanks, Peter Gavin Gtk2HS Release Manager ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] GMP on Mac OS X linked statically by default
Was there a reason for this? If so, it'd be nice if the package that was build explained why... otherwise it feels kind of arbitrary, and would be nice if there was documentation available to make it link dynamically in case someone didn't want to LGPL their program. Anyone know the steps to make it link dynamically? Dave ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: [Gtk2hs-users] Gtk2HS 0.10.0 Released
Wonderful! Who maintains the mac-ports port of it? I'm itching to get hieroglyph working on the Mac. On Tue, Feb 10, 2009 at 11:40 PM, Peter Gavin pga...@gmail.com wrote: Hi everyone, Oh, dear... it seems I've forgotten how to spell cafe, and sent this message to haskell-c...@haskell.org the first time around. I resent it to all the lists again (just to make sure everyone interested receives it), so I apologize for any duplicated messages you might have received. In any case... I'd like to release the announcement of Gtk2HS 0.10.0. A lot of new stuff has gone into this release, including: - Support for GHC 6.10 - Bindings to GIO and GtkSourceView-2.0 - Full switch to the new model-view implementation using a Haskell model - Support for many more model-based widgets such as IconView and an updated binding for ComboBox - Full Drag-and-Drop support - Better support for Attributes in Pango - Replaced Event for EventM monad, thereby improving efficiency and convenience - Functions for interaction between Cairo and Pixbuf drawing - Lots of bug fixes, code cleanups, and portability improvements With this release, the bindings to GnomeVFS and GtkSourceView-1.0 have been deprecated. The TreeList modules have been deprecated from the Gtk+ bindings. Source and Win32 binaries are available at: https://sourceforge.net/project/showfiles.php?group_id=49207package_id=42440release_id=659598 Thanks to everyone who submitted bug fixes and features this time around! Thanks, Peter Gavin Gtk2HS Release Manager -- Create and Deploy Rich Internet Apps outside the browser with Adobe(R)AIR(TM) software. With Adobe AIR, Ajax developers can use existing skills and code to build responsive, highly engaging applications that combine the power of local resources and data with the reach of the web. Download the Adobe AIR SDK and Ajax docs to start building applications today-http://p.sf.net/sfu/adobe-com ___ Gtk2hs-users mailing list gtk2hs-us...@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/gtk2hs-users ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: [Haskell] Google Summer of Code 2009
On Tue, Feb 10, 2009 at 6:26 AM, Malcolm Wallace malcolm.wall...@cs.york.ac.uk wrote: Gentle Haskellers, The Google Summer of Code will be running again this year. Once again, haskell.org has the opportunity to bid to become a mentoring organisation. (Although, as always, there is no guarantee of acceptance.) If you have ideas for student projects that you think would benefit the Haskell community, now is the time to start discussing them on mailing lists of your choice. 1. Binding for FireBird RDBMS. 2. Library for manipulate ODF. 3. Binding to OOo UNO. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] GMP on Mac OS X linked statically by default
leimy2k: Was there a reason for this? If so, it'd be nice if the package that was build explained why... otherwise it feels kind of arbitrary, and would be nice if there was documentation available to make it link dynamically in case someone didn't want to LGPL their program. Anyone know the steps to make it link dynamically? Here's how we do it on Windows. The Mac should be far easier, http://haskell.forkio.com/gmpwindows -- Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Gtk2HS 0.10.0 Released
Well done! Our flagship GUI bindings... Go team! -- Don pgavin: Hi everyone, Oh, dear... it seems I've forgotten how to spell cafe, and sent this message to haskell-c...@haskell.org the first time around. I resent it to all the lists again (just to make sure everyone interested receives it), so I apologize for any duplicated messages you might have received. In any case... I'd like to release the announcement of Gtk2HS 0.10.0. A lot of new stuff has gone into this release, including: - Support for GHC 6.10 - Bindings to GIO and GtkSourceView-2.0 - Full switch to the new model-view implementation using a Haskell model - Support for many more model-based widgets such as IconView and an updated binding for ComboBox - Full Drag-and-Drop support - Better support for Attributes in Pango - Replaced Event for EventM monad, thereby improving efficiency and convenience - Functions for interaction between Cairo and Pixbuf drawing - Lots of bug fixes, code cleanups, and portability improvements With this release, the bindings to GnomeVFS and GtkSourceView-1.0 have been deprecated. The TreeList modules have been deprecated from the Gtk+ bindings. Source and Win32 binaries are available at: https://sourceforge.net/project/showfiles.php?group_id=49207package_id=42440release_id=659598 Thanks to everyone who submitted bug fixes and features this time around! Thanks, Peter Gavin Gtk2HS Release Manager ___ 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
