Re: [Haskell-cafe] bytestring vs. uvector

2009-03-07 Thread Don Stewart
bos: > On Sat, Mar 7, 2009 at 10:23 PM, Alexander Dunlap > wrote: > > Hi all, > > For a while now, we have had Data.ByteString[.Lazy][.Char8] for our > fast strings. Now we also have Data.Text, which does the same for > Unicode. These seem to be the standard for dealing with list

Re: [Haskell-cafe] bytestring vs. uvector

2009-03-07 Thread Austin Seipp
Excerpts from Bryan O'Sullivan's message of Sun Mar 08 00:45:03 -0600 2009: > uvector is, if my memory serves me correctly, a fork of the vector library. > It uses modern stream fusion, but is under active development and is a > little scary. I'm a little unclear on the exact difference between uve

Re: [Haskell-cafe] bytestring vs. uvector

2009-03-07 Thread Austin Seipp
Excerpts from Alexander Dunlap's message of Sun Mar 08 00:23:01 -0600 2009: > For a while now, we have had Data.ByteString[.Lazy][.Char8] for our > fast strings. Now we also have Data.Text, which does the same for > Unicode. These seem to be the standard for dealing with lists of bytes > and charac

Re: [Haskell-cafe] bytestring vs. uvector

2009-03-07 Thread Bryan O'Sullivan
On Sat, Mar 7, 2009 at 10:23 PM, Alexander Dunlap < alexander.dun...@gmail.com> wrote: > Hi all, > > For a while now, we have had Data.ByteString[.Lazy][.Char8] for our > fast strings. Now we also have Data.Text, which does the same for > Unicode. These seem to be the standard for dealing with lis

[Haskell-cafe] bytestring vs. uvector

2009-03-07 Thread Alexander Dunlap
Hi all, For a while now, we have had Data.ByteString[.Lazy][.Char8] for our fast strings. Now we also have Data.Text, which does the same for Unicode. These seem to be the standard for dealing with lists of bytes and characters. Now we also have the storablevector, uvector, and vector packages. T

Re: [Haskell-cafe] I want to write a compiler

2009-03-07 Thread wren ng thornton
Loup Vaillant wrote: -> support algebraic data types and case expressions (unless I can get away with encoding them as functions), Which you always can, data Foo = A a1...an | B b1...bn |... == type Foo :: forall r. (a1->...->an -> r) -> (b1->...->bn -

Re: [Haskell-cafe] Purely Functional Data Structures

2009-03-07 Thread Jeremy Shaw
At Sun, 08 Mar 2009 02:28:43 +0100, G?uenther Schmidt wrote: > > [1 ] > Hi Jeremy, > > I had used HAppS-IxSet before and was very happy with it, it offered > pretty much everything I needed. I switched (back) to SQL once I had hit > a bump in the road that I wasn't able to fix, a stack-overflo

[Haskell-cafe] Re: cabal-install 0.6.2 does not bootstrap with ghc-6.10.1 debian distribution

2009-03-07 Thread Ahn, Ki Yung
Ahn, Ki Yung 쓴 글: > Dear Haskellers and especially who are working on cabal-install > and debian packaging, > > I sometimes clean up .ghc and .cabal in my home directory to start from > scratch because of dependency loopholes (cabal-install does not have > remove option yet, so it's hard to fix wh

[Haskell-cafe] cabal-install 0.6.2 does not bootstrap with ghc-6.10.1 debian distribution

2009-03-07 Thread Ahn, Ki Yung
Dear Haskellers and especially who are working on cabal-install and debian packaging, I sometimes clean up .ghc and .cabal in my home directory to start from scratch because of dependency loopholes (cabal-install does not have remove option yet, so it's hard to fix when such loophole happens). To

Re: [Haskell-cafe] I want to write a compiler

2009-03-07 Thread Austin Seipp
Hi, (Please note this is coming from my own experience working with the LHC haskell compiler, as well as a compiler I'm currently working on in SML. I'm not an authority, but as another greenhorn compiler hacker I thought I might give some advice.) Excerpts from Loup Vaillant's message of Sat Mar

Re: [Haskell-cafe] Purely Functional Data Structures

2009-03-07 Thread G?uenther Schmidt
Hi Jeremy, I had used HAppS-IxSet before and was very happy with it, it offered pretty much everything I needed. I switched (back) to SQL once I had hit a bump in the road that I wasn't able to fix, a stack-overflow that occurred once I ran the code against the largest sample data I had. It o

Re: [Haskell-cafe] I want to write a compiler

2009-03-07 Thread Jeremy Shaw
Hello, This book is pretty good IMO: http://research.microsoft.com/en-us/um/people/simonpj/papers/slpj-book-1987/ It does not cover STG, but it does cover a ton of useful stuff and is very well written. I can say from experience that the spineless-tagless-gmachine paper you referenced does cont

Re: [Haskell-cafe] Purely Functional Data Structures

2009-03-07 Thread Jeremy Shaw
At Sun, 08 Mar 2009 00:13:14 +0100, G?uenther Schmidt wrote: > In SQL I would have the data indexed by several > different columns, if I use maps I'd only have one key, so if I need to > lookup data in the map by a value that is not the key the lookups will > become quite expensive. happstack-i

[Haskell-cafe] Re: I want to write a compiler

2009-03-07 Thread Achim Schneider
Rick R wrote: > http://en.wikibooks.org/wiki/Write_Yourself_a_Scheme_in_48_Hours > Or go for the Real Thing: http://mitpress.mit.edu/sicp/full-text/book/book-Z-H-35.html#%_sec_5.5 (although starting to read the Wizard book with the last section might not be the most easiest thing in the world)

Re: [Haskell-cafe] I want to write a compiler

2009-03-07 Thread Rick R
http://en.wikibooks.org/wiki/Write_Yourself_a_Scheme_in_48_Hours Not sure if this is exactly what you want, but you could certainly fufill all of your requirements using this as a baseline. Instead of evaluating the actual statements in your eval function, you could simply render them to C. As fa

[Haskell-cafe] I want to write a compiler

2009-03-07 Thread Loup Vaillant
This is a homework question. I am mainly looking for guidance or pointers. Source code, even. (Not GHC's, though, it is too complicated for me right now. The AST of STG is fine, but the rest kinda scares me.) Ideally, I would very much like to compile to C. The requirements are easily stated. My

[Haskell-cafe] Haskell Weekly News: Issue 108 - March 7, 2009

2009-03-07 Thread Brent Yorgey
--- Haskell Weekly News http://sequence.complete.org/hwn/20090307 Issue 108 - March 07, 2009 --- Welcome to issue 108 of HWN, a newsletter covering

[Haskell-cafe] Re: a newbies confusion with repositories - darcs or git

2009-03-07 Thread Trent W. Buck
Eric Kow writes: > One of the darcs team members, Thorkil Naur, felt that in my enthusiasm I > was not being sufficiently forthright about darcs's shortcomings. As for me, I tend to start any review with a list of all the problems I have with , on the basis that it's a lot harder to find informe

Re: [Haskell-cafe] Purely Functional Data Structures

2009-03-07 Thread G?uenther Schmidt
Hi Don, damn, that was quick! And thx, I'll look into that. The reading it in wasn't much of a problem, I had been able to use MS-ODBC for that, there's a driver for ODBC files. The problem is more the type of data structure I'd be reading it into. In SQL I would have the data indexed by seve

Re: [Haskell-cafe] Purely Functional Data Structures

2009-03-07 Thread Don Stewart
gue.schmidt: > Hi, > > is the above mentioned book still *the* authority on the subject? > > I bought the book, read about 10 pages and then put it back on the > shelf. Um. > In my app I have to deal with 4 csv files, each between 5 - 10 mb, and > some static data. > > I had put all that data

[Haskell-cafe] Purely Functional Data Structures

2009-03-07 Thread Gü?nther Schmidt
Hi, is the above mentioned book still *the* authority on the subject? I bought the book, read about 10 pages and then put it back on the shelf. Um. In my app I have to deal with 4 csv files, each between 5 - 10 mb, and some static data. I had put all that data into an Sqlite3 database and us

Re: [Haskell-cafe] Naturality condition for inits

2009-03-07 Thread Daniel Fischer
Am Samstag, 7. März 2009 23:18 schrieb R J: > Here's another Bird problem that's stymied me: > > The function "inits" computes the list of initial segments of a list; its > type is inits :: [a] -> [[a]]. What is the appropriate naturality > condition for "inits"? > > The only discussion in the tex

Re: [Haskell-cafe] Naturality condition for inits

2009-03-07 Thread Derek Elkins
On Sat, 2009-03-07 at 22:18 +, R J wrote: > Here's another Bird problem that's stymied me: > > The function "inits" computes the list of initial segments of a list; > its type is inits :: [a] -> [[a]]. What is the appropriate naturality > condition for "inits"? A natural transformation is be

Re: [Haskell-cafe] Converting list comprehensions to combinatory style

2009-03-07 Thread Daniel Fischer
Am Samstag, 7. März 2009 23:06 schrieb R J: > Can anyone help with this problem from Bird: > > a. Convert the following list comprehensions to combinatory style: > >i. [(x, y) | x <- [1..n], odd x, y <- [1..n]] >ii. [(x, y) | x <- [1..n], y <- [1..n], odd x] > > b. Are they equal? > > c.

Re: [Haskell-cafe] do you have to use fix with forkio?

2009-03-07 Thread Martijn van Steenbergen
Derek Elkins wrote: If you are doing something else, use something else. This makes it clear that you -aren't- going to break out (non-exceptionally), i.e. the control flow is more obvious in this code than in the other versions. Oh yes, of course! I wasn't saying forever is bad; in fact I agr

Re: [Haskell-cafe] do you have to use fix with forkio?

2009-03-07 Thread Derek Elkins
On Sat, 2009-03-07 at 23:12 +0100, Martijn van Steenbergen wrote: > Derek Elkins wrote: > > Both are poorish style. > > > > reader <- forkIO $ forever $ do (nr', line) <- readChan; when (nr /= nr') $ > > putStrLn hdl line > > This is fine assuming you always want to re-enter the loop. If you wan

[Haskell-cafe] Naturality condition for inits

2009-03-07 Thread R J
Here's another Bird problem that's stymied me: The function "inits" computes the list of initial segments of a list; its type is inits :: [a] -> [[a]]. What is the appropriate naturality condition for "inits"? The only discussion in the text concerning naturality conditions concerns map, whe

Re: [Haskell-cafe] do you have to use fix with forkio?

2009-03-07 Thread Martijn van Steenbergen
Derek Elkins wrote: Both are poorish style. reader <- forkIO $ forever $ do (nr', line) <- readChan; when (nr /= nr') $ putStrLn hdl line This is fine assuming you always want to re-enter the loop. If you want to loop conditionally (which is most often the case), forever isn't going to work

[Haskell-cafe] Converting list comprehensions to combinatory style

2009-03-07 Thread R J
Can anyone help with this problem from Bird: a. Convert the following list comprehensions to combinatory style: i. [(x, y) | x <- [1..n], odd x, y <- [1..n]] ii. [(x, y) | x <- [1..n], y <- [1..n], odd x] b. Are they equal? c. Compare the costs of evaluating the two expressions. I ga

Re: [Haskell-cafe] Re: Ambiguous type with PolymorphicComponents

2009-03-07 Thread Daniel Fischer
Am Samstag, 7. März 2009 21:48 schrieb Maurí­cio: > >> (...) > > > > When you have > > > > data Test = Test (forall w. (C1 w, C2 w, ..., Cn w) => w) > > > > and > > > > function (Test w) = classmethod w, > > > > there is no way to decide which instance to use, hence the type variable > > is ambigu

[Haskell-cafe] Re: Ambiguous type with PolymorphicComponents

2009-03-07 Thread Maurí­cio
>> (...) When you have data Test = Test (forall w. (C1 w, C2 w, ..., Cn w) => w) and function (Test w) = classmethod w, there is no way to decide which instance to use, hence the type variable is ambiguous. (...) But, then, how can I reach the data inside a polymorphic component? Or, be

Re: [Haskell-cafe] serializing large data structures, stack overflow

2009-03-07 Thread Bulat Ziganshin
Hello friggin, Saturday, March 7, 2009, 10:57:04 PM, you wrote: > dec = B.decodeFile "C:/users/saftarn/desktop/bintest.txt" >>= \a -> >   return $ (a :: M.Map (Int,Int) Int) just a quick style hack: dec = B.decodeFile "C:/users/saftarn/desktop/bintest.txt" :: IO (M.Map (Int,Int) Int) --

Re: [Haskell-cafe] Ambiguous type with PolymorphicComponents

2009-03-07 Thread Daniel Fischer
Am Samstag, 7. März 2009 20:28 schrieb Maurí­cio: > Hi, > > When reading this code in ghci, I get an > ambiguous type at last line: > > > {-# LANGUAGE PolymorphicComponents #-} > {-# LANGUAGE RankNTypes #-} > import Graphics.UI.Gtk > data Test = Test (forall w. WidgetClass w => w) > toAction (Test

Re: [Haskell-cafe] serializing large data structures, stack overflow

2009-03-07 Thread Don Stewart
import Data.Binary and then write a variant of something like how Maps are currently serialised: instance (Ord k, Binary k, Binary e) => Binary (Map.Map k e) where put m = put (Map.size m) >> mapM_ put (Map.toAscList m) get = liftM Map.fromDistinctAscList get So you might w

Re: [Haskell-cafe] serializing large data structures, stack overflow

2009-03-07 Thread Don Stewart
Increase the stack size, or use a different serialiser (they're only a half dozen lines to write), or different data structure? -- Don frigginfriggins: > I'm playing around with Netflix, implementing a simple KNN-algorithm, I will > later try SVD which seems to be the most successful approach. >

[Haskell-cafe] serializing large data structures, stack overflow

2009-03-07 Thread friggin friggin
I'm playing around with Netflix, implementing a simple KNN-algorithm, I will later try SVD which seems to be the most successful approach. Using a database like Postgresqk is to slow so I want to serialize a datastructure containing the ratings. I'm not sure about the representation I will use jus

[Haskell-cafe] Re: a newbies confusion with repositories - darcs or git

2009-03-07 Thread Eric Kow
Hi again, I wanted to echo Iavor's comment that you shouldn't feel 'obliged' to use darcs out of Haskell brand loyalty. Try both systems out and see how they feel. My enthusiasm is really about what I find to be a great and very comfortable workflow. You'll have to see for yourself what suits y

[Haskell-cafe] Ambiguous type with PolymorphicComponents

2009-03-07 Thread Maurí­cio
Hi, When reading this code in ghci, I get an ambiguous type at last line: {-# LANGUAGE PolymorphicComponents #-} {-# LANGUAGE RankNTypes #-} import Graphics.UI.Gtk data Test = Test (forall w. WidgetClass w => w) toAction (Test w) = toWidget w It's interesting that if I replace 'Integral' for

[Haskell-cafe] Re: Zippers

2009-03-07 Thread Heinrich Apfelmus
Cristiano Paris wrote: > Heinrich Apfelmus wrote: >> ... >> Such self-reference is usually called "tying the knot", see also >> >> http://www.haskell.org/haskellwiki/Tying_the_Knot > > I didn't know. Would you call this "Tying the knot" as well? > > http://yi-editor.blogspot.com/2008/12/prototyp

Re: [Haskell-cafe] Mystified by Cabal

2009-03-07 Thread Don Stewart
colin: > I have just attempted Cabal-izing my program (splitting it into a > library and main program as well), and I'm mystified by some problems > I am having. > > First, when I try to build the library I get: > > [co...@susannah game-tree]$ runhaskell Setup build > Preprocessing library game-t

Re: [Haskell-cafe] FRP + physics / status of hpysics

2009-03-07 Thread Roman Cheplyaka
* Peter Verswyvelen [2009-03-07 18:34:10+0100] > On Fri, Mar 6, 2009 at 10:39 PM, Roman Cheplyaka wrote: > > > > The blog > > > seems to be inactive since december 2008; has development ceased? > > > > Sort of. One reason is that DPH does not seem to be ready for hpysics > > yet, another one is

Re: [Haskell-cafe] FRP + physics / status of hpysics

2009-03-07 Thread Felipe Lessa
2009/3/6 Peter Verswyvelen : > Do alternatives exist? Maybe good wrappers (hopefully pure...)  around > existing engines? There's Hipmunk, but it is not pure and not that good ;). But if you don't mess with the global variables (which you normally wouldn't mess anyway) then you can wrap everything

Re: [Haskell-cafe] Mystified by Cabal

2009-03-07 Thread Colin Paul Adams
> "Robin" == Robin Green writes: Robin> The build-depends line needs to go in the Library section, Robin> I think. It doesn't seem to be having any effect in its Robin> current location. Likewise for ghc-options. Thanks everyone - it's working now. -- Colin Adams Preston Lancash

Re: [Haskell-cafe] Mystified by Cabal

2009-03-07 Thread Robin Green
On Sat, 07 Mar 2009 17:30:43 + Colin Paul Adams wrote: > > "Svein" == Svein Ove Aas writes: > > >> Preprocessing library game-tree-1.0.0.0... Building > >> game-tree-1.0.0.0... > >> > >> Data/Tree/Game/Negascout.hs:31:0: Unrecognised pragma [1 of 2] > >> Compiling

Re[2]: [Haskell-cafe] Mystified by Cabal

2009-03-07 Thread Bulat Ziganshin
Hello Colin, Saturday, March 7, 2009, 8:30:43 PM, you wrote: > >> Data/Tree/Game/Tree.hs:1:0:    Failed to load interface for > >> `Prelude':      it is a member of package base-3.0.3.0, which > >> is hidden > build-depends: base >= 4 and which ghc version you are running? :)

Re: [Haskell-cafe] FRP + physics / status of hpysics

2009-03-07 Thread Peter Verswyvelen
On Fri, Mar 6, 2009 at 10:39 PM, Roman Cheplyaka wrote: > > The blog > > seems to be inactive since december 2008; has development ceased? > > Sort of. One reason is that DPH does not seem to be ready for hpysics > yet, another one is that I don't see any potential users around (read: I > just ne

Re: [Haskell-cafe] Mystified by Cabal

2009-03-07 Thread Colin Paul Adams
> "Svein" == Svein Ove Aas writes: >> Preprocessing library game-tree-1.0.0.0... Building >> game-tree-1.0.0.0... >> >> Data/Tree/Game/Negascout.hs:31:0: Unrecognised pragma [1 of 2] >> Compiling Data.Tree.Game.Tree ( Data/Tree/Game/Tree.hs, >> dist/build/Data/Tree/G

Re: [Haskell-cafe] Mystified by Cabal

2009-03-07 Thread Svein Ove Aas
On Sat, Mar 7, 2009 at 6:18 PM, Colin Paul Adams wrote: > I have just attempted Cabal-izing my program (splitting it into a > library and main program as well), and I'm mystified by some problems > I am having. > > First, when I try to build the library I get: > > [co...@susannah game-tree]$ runha

[Haskell-cafe] Mystified by Cabal

2009-03-07 Thread Colin Paul Adams
I have just attempted Cabal-izing my program (splitting it into a library and main program as well), and I'm mystified by some problems I am having. First, when I try to build the library I get: [co...@susannah game-tree]$ runhaskell Setup build Preprocessing library game-tree-1.0.0.0... Building

[Haskell-cafe] Running HUnit tests when pushing to darcs on haskell.org

2009-03-07 Thread Colin Paul Adams
Hello cafe, I've just followed the instructions at http://www.haskell.org/haskellwiki/How_to_write_a_Haskell_program to create my first library project on haskell.org, using darcs. I tried using the darcs setpref test command to execute: runhaskell tests/*.hs (which works locally) but it fail

Re: [Haskell-cafe] Interesting problem from Bird (4.2.13)

2009-03-07 Thread Bas van Dijk
2009/3/4 R J : > Could someone provide an elegant solution to Bird problem 4.2.13? > > Here are the problem and my inelegant solution: > > Problem > --- > > Since concatenation seems such a basic operation on lists, we can try to > construct a data type that captures > concatenation as a primit