Clojure has a commute operator whose semantics seem appropriate to your
concerns:
http://clojure.org/refs
http://richhickey.github.com/clojure/clojure.core-api.html#clojure.core/commute
Commute in haskell would be roughly :: TVar a - (a - a) - STM a.
The TVar touched by commute does not get
2010/9/29 Tom Hawkins tomahawk...@gmail.com:
On Tue, Sep 28, 2010 at 9:20 PM, Shakthi Kannan shakthim...@gmail.com wrote:
If you are still at it, you can have a look at Chalmers Lava [1], or
Kansas Lava [2].
Feldspar [3] project targets DSP though.
These are examples light embedded DSLs,
Am 29.09.2010 05:35, schrieb Peter Schmitz:
[...]
Error parsing file: ...\sampleTaggedContent.txt (line 4, column 1):
unexpected end of input
expecting
The input was:
[...]
-- Parsers:
taggedContent = do
optionalWhiteSpace
aTag
many tagOrContent
aTag
many tagOrContent
Don Stewart:
tomahawkins:
A few years ago I attempted to build a Haskell hardware compiler
(Haskell - Verilog) based on the Yhc frontent. At the time I was
trying to overcome several problems [1] with implementing a hardware
description language as a light eDSL, which convinced me a
Hi Tom,
You wrote that you are interested in the programming experience with relaxed
atomicity. What you are asking for are the ideas behind Twilight STM, written
in these papers:
http://proglang.informatik.uni-freiburg.de/projects/syncstm/techreport2010twilight.pdf
(brief summary of the
On 28 sep 2010, at 17:33, Ozgur Akgun wrote:
How do you define relationships between data types?
Well, why is it any different from other fields? From one of your examples
[1], I'd expect you to have a list of questions in the Quiz data type, and if
necessary, a quiz field in the Question
If you are really interested in embedded realtime code you may want to have a
look at the timber language[1] or bit-c[2]. Another very interesting project
is this[3] developing a new Haskell like language called Habit for systems
programming.
There are also some great papers about systems
Am 29.09.2010 09:54, schrieb Christian Maeder:
Am 29.09.2010 05:35, schrieb Peter Schmitz:
[...]
Error parsing file: ...\sampleTaggedContent.txt (line 4, column 1):
unexpected end of input
expecting
The input was:
[...]
-- Parsers:
taggedContent = do
optionalWhiteSpace
aTag
OK, I am rephrasing it a bit then :)
I definitely don't think this would be trivial to implement. However, I'd
expect a decent solution to this problem, not to have special combinators to
describe relations between data types, but let the user model their data
using plain haskell data types, and
I think this approach is not possible without involving some fairly
ugly unsafeInterleaveIO/unsafePerformIO calls. A simple example using
a common web programming example: support I have a multi-user blog
site, where each user can have multiple entries. I would model this
using standard Haskell
Ryan Ingram wrote:
I saw the winner was announced. Is there a highscore table? We were
in the top 5, I want to see how well we did.
Only the winners were announced at the conference - no highscore
table. The organisers may put more detail on the contest website
perhaps?
Regards,
Am 29.09.2010 11:55, schrieb Christian Maeder:
Am 29.09.2010 09:54, schrieb Christian Maeder:
Am 29.09.2010 05:35, schrieb Peter Schmitz:
[...]
Error parsing file: ...\sampleTaggedContent.txt (line 4, column 1):
unexpected end of input
expecting
The input was:
[...]
-- Parsers:
On 28 September 2010 21:12, Jeremy Shaw jer...@n-heptane.com wrote:
Not sure what that means. But I am only willing to maintain so many
wiki pages. So far at least three have come up in this thread.
Why?
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lhae[1] is a spreadsheet program. It features a simple formula language
and some basic statistical methods, like descriptive statistics and pivot
tables.
0.0.2 - 0.0.3:
---
Improvements:
- Right click menu at columns/row headers and cells
- Insert rows/columns between exisiting
A new graphics library:
http://hackage.haskell.org/package/collada-output
Most of the graphics libraries on hackage use OpenGL to visualize 3d
objects.
With this library you now have the choice to use an external tool for
visualization and enjoy the flexibility of
a standard format for 3d
I still cannot seem to get a GUI working under Windows.
For Haskell GUI's is Ubuntu easier to setup.
If so, we're losing people if Haskell GUI's are so hard to get working
under Windows.
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I have a question about Parsec. The following program
import Control.Applicative ((*),(*))
import Text.Parsec
import Text.Parsec.Char
block p = char '{' * p * char '}'
parser = block (many digit)
main = parseTest parser {123a}
gives the output
parse error at (line 1, column 5):
I need the trick to get from
ByteString - [GHC.Word.Word8]
and Hayoo is not helping.
Super simple I expected. I haven't even tried to compile it yet.
I am just trying to read in the bytes and encode with base64:
import Codec.Binary.Base64
import Data.ByteString
import
On Wed, Sep 29, 2010 at 11:03 AM, Roderick Ford develo...@live.com wrote:
I need the trick to get from
ByteString - [GHC.Word.Word8]
and Hayoo is not helping.
Super simple I expected. I haven't even tried to compile it yet.
I am just trying to read in the bytes and encode with base64:
By and large hayoo is the alta-vista of Haskell search - it has a huge
database but isn't well organized or good at prioritizing. Use Hoogle
when doing type-based searches for functions in the typical GHC load.
http://haskell.org/hoogle/?hoogle=%3A%3A+ByteString+-%3E+[Word8]
Also, what's with
The idea was to go from
Prelude :t Data.ByteString.readFile
Data.ByteString.readFile
:: FilePath - IO Data.ByteString.Internal.ByteString
to here
Prelude :t Codec.Binary.Base64.encode
Codec.Binary.Base64.encode :: [GHC.Word.Word8] - String
unless there is another/easier way
In addition to hoogle I suggest you check out hackage too. I think
you'll be particularly interested in base64-bytestring:
http://hackage.haskell.org/package/base64-bytestring
Cheers,
Thomas
On Wed, Sep 29, 2010 at 9:41 AM, Roderick Ford develo...@live.com wrote:
The idea was to go from
YES!! Thank you so much.
And thanks to Thomas also for the suggestion of using Data.ByteString.Base64
... as the alternative method.
Cheers,
Roderick
Date: Wed, 29 Sep 2010 11:11:01 -0500
Subject: Re: [Haskell-cafe] can't find in hayoo
From: aslat...@gmail.com
To:
Ben Franksen wrote:
import Control.Applicative ((*),(*))
import Text.Parsec
import Text.Parsec.Char
block p = char '{' * p * char '}'
parser = block (many digit)
main = parseTest parser {123a}
gives the output
parse error at (line 1, column 5):
unexpected a
expecting }
Note
Hi,
on planet.debian.org, there is some ill-tempered discussion about the
seemingly bad relationship between the Ruby community and Debian
maintainers. The following blog post summarizes the issues quite well
and calmly:
http://gwolf.org/blog/ruby-dissonance-debian-again
With the Haskell
On Wednesday 29 September 2010 19:10:22, Ben Franksen wrote:
Note the last line mentions only '}'. I would rather like to see
expecting } or digit
since the parser could very well accept another digit here.
parsec2 did that, I don't know whether that change is intentional or
There are issues, yes, and you may need the MinGW tool chain to get the GUI
packages to build and install properly, but it does work. I have blogged
about some of my experiences, both good and bad, at
http://jpmoresmau.blogspot.com/. What GUI tool specifically do you want to
use?
JP
On Wed, Sep
On 29 September 2010 17:01, cas...@istar.ca wrote:
I still cannot seem to get a GUI working under Windows.
For Haskell GUI's is Ubuntu easier to setup.
If so, we're losing people if Haskell GUI's are so hard to get working under
Windows.
We're losing people! Charge!
I think the problem is
Hi,
I have the following code:
{-# LANGUAGE TypeSynonymInstances #-}
data Vect k b = V [(k,b)]
-- vector space over field k with basis b
-- for example, V [(5, E 1), (7, E 2)] would represent the vector 5 e1 + 7 e2
data Monomial v = M [(v,Int)]
-- monomials over variables v
-- for example, M
Maybe -XLiberalTypeSynonyms is an option:
http://www.haskell.org/ghc/docs/6.12.2/html/users_guide/data-type-extensions.html#type-synonyms
On 29 September 2010 20:08, DavidA polyom...@f2s.com wrote:
Hi,
I have the following code:
{-# LANGUAGE TypeSynonymInstances #-}
data Vect k b = V
On Wed, 29 Sep 2010 20:08:07 +0200, you wrote:
I think the problem is lack of Windows developers interested in GUIs,
and that Windows is not so POSIXy-development-friendly as Linux or OS
X. But mostly lack of people interested in that area, I think.
There are lots of Windows developers
I imagine that getting Haskell GUI libraries set and playing nice with
the native GTK libs is a pain on Windows.
That said, I know that Haskell has very nice Lua bindings and Lua has
pretty mature GTK bindings. Has anyone tried developing their UI in
Lua with Haskell doing all the heavy lifting?
On 29 September 2010 20:33, Steve Schafer st...@fenestra.com wrote:
There are lots of Windows developers interested in GUIs. [..]
The issue isn't that there aren't a lot of Windows developers who have
an interest in Haskell+GUI development.
Yeah, what do you think I meant? We're talking about
On Wed, Sep 29, 2010 at 11:08 AM, DavidA polyom...@f2s.com wrote:
Hi,
I have the following code:
{-# LANGUAGE TypeSynonymInstances #-}
data Vect k b = V [(k,b)]
-- vector space over field k with basis b
-- for example, V [(5, E 1), (7, E 2)] would represent the vector 5 e1 + 7 e2
data
On 29 September 2010 20:48, Ryan Ingram ryani.s...@gmail.com wrote:
But it doesn't let you partially apply the type synonym.
On the other hand, if you did this:
newtype Compose f g a = O { unO :: f (g a) }
type Poly k = Compose (Vect k) Monomial
instance Monad (Poly k) where ...
would
On Wednesday 29 September 2010 2:52:21 pm Christopher Done wrote:
LiberalTypeSynonyms lets you partially apply type synonyms.
Not in general. LiberalTypeSynonyms only allows synonyms to be partially
applied when expansions of other type synonyms will eventually cause them to
become fully
On Wed, 29 Sep 2010 20:44:22 +0200, you wrote:
Yeah, but not liking wrestling with libraries isn't peculiar to
Haskell developers. There just needs to be enough people that the
probability of there being a person who will bother to wrestle with it
is high enough. Hence, the issue is lack of
S. Doaitse Swierstra schrieb:
Avoiding repeated additions:
movingAverage :: Int - [Float] - [Float]
movingAverage n l = runSums (sum . take n $l) l (drop n l)
where n' = fromIntegral n
runSums sum (h:hs) (t:ts) = sum / n' : runSums (sum-h+t) hs ts
runSums _
On 29/09/2010 02:18 PM, Henning Thielemann wrote:
Andrew Coppin wrote:
Tastes do indeed vary. To me, both of these are incorrect, and the
correct way is
data Foo a b =
Fooa |
Bar b |
Foobar a b
deriving (Eq, Ord)
The truth is: Given the separator style
Daniel Fischer wrote:
On Wednesday 29 September 2010 19:10:22, Ben Franksen wrote:
Note the last line mentions only '}'. I would rather like to see
expecting } or digit
since the parser could very well accept another digit here.
parsec2 did that, I don't know whether that change
On 29 sep 2010, at 00:58, o...@cs.otago.ac.nz wrote:
Avoiding repeated additions:
movingAverage :: Int - [Float] - [Float]
movingAverage n l = runSums (sum . take n $l) l (drop n l)
where n' = fromIntegral n
runSums sum (h:hs) (t:ts) = sum / n' : runSums (sum-h+t) hs ts
On 29/09/2010 07:33 PM, Steve Schafer wrote:
The issue isn't that there aren't a lot of Windows developers who have
an interest in Haskell+GUI development. The issue is that nearly every
Windows developer who looks into Haskell+GUI says, This stuff sucks,
and walks away, because they're
Hi Tom,
The Utrecht Haskell Compiler (UHC) is internally organized as a set of
compilers, for which you can configure the aspects you want. It is relatively
easy to extract such a particular combination and use it as a starting point.
Or you might install UHC itself and use the installed
Ryan Ingram ryani.spam at gmail.com writes:
Haskell doesn't have true type functions; what you are really saying is
instance Monad (\v - Vect k (Monomial v))
Yes, that is exactly what I am trying to say. And since I'm not allowed to say
it like that, I was trying to say it using a type
On Wednesday 29 September 2010 23:02:02, Andrew Coppin wrote:
So anyway, that's the problem. The solution is...
Two obvious solutions.
- stop using Windows and migrate to an OS where stuff works pretty much out
of the box (not going to happen a lot)
- start helping to make things work on
On Wednesday 29 September 2010 23:15:14, DavidA wrote:
Ryan Ingram ryani.spam at gmail.com writes:
Haskell doesn't have true type functions; what you are really saying
is
instance Monad (\v - Vect k (Monomial v))
Yes, that is exactly what I am trying to say. And since I'm not allowed
It's hard. Here's a simple example:
type Foo f = f Int
class C (f :: (* - *) - *) where
thingy :: f [] - f IO
-- Should this ever typecheck? I would say no; there's no way to
unify f [] with [Int].
callThingy :: [Int] - IO Int
callThingy = thingy
-- but what if you say this?
instance C
On Wed, Sep 29, 2010 at 11:15 PM, DavidA polyom...@f2s.com wrote:
Ryan Ingram ryani.spam at gmail.com writes:
Haskell doesn't have true type functions; what you are really saying is
instance Monad (\v - Vect k (Monomial v))
Yes, that is exactly what I am trying to say. And since I'm not
Andrew Coppin wrote:
On 29/09/2010 07:33 PM, Steve Schafer wrote:
The issue isn't that there aren't a lot of Windows developers who have
an interest in Haskell+GUI development. The issue is that nearly every
Windows developer who looks into Haskell+GUI says, This stuff sucks,
and walks
These were enough to get me started:
http://www.haskell.org/haskellwiki/Opengl
http://haskell.forkio.com/com-examples
http://darcs.haskell.org/packages/Win32/examples/
Roderick
Date: Wed, 29 Sep 2010 11:01:50 -0400
From: cas...@istar.ca
To: haskell-cafe@haskell.org
The organisers may put more detail on the contest website perhaps?
Will do, after I get home from ICFP. - Best, Johannes.
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When I change the cabal file to say
preference: base = 4
I still get, you are using base 3.0 which is deprecated.
When I change the overall cabal profile, the error message still comes up.
It seems like some other part of the install process is controlling
the base version, besides the *.cabal
On Thursday 30 September 2010 00:56:56, cas...@istar.ca wrote:
When I change the cabal file to say
preference: base = 4
In the .cabal file of a package, that would belong in the build-depends.
I still get, you are using base 3.0 which is deprecated.
When I change the overall cabal profile,
On Wed, Sep 29, 2010 at 3:56 PM, cas...@istar.ca wrote:
When I change the cabal file to say
preference: base = 4
I still get, you are using base 3.0 which is deprecated.
When I change the overall cabal profile, the error message still comes up.
It seems like some other part of the install
Antoine and Christian:
Many thanks for your help on this thread.
(I am still digesting it; much appreciated; will post when I get it working.)
-- Peter
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On 09/29/2010 02:15 PM, DavidA wrote:
instance Monad (\v - Vect k (Monomial v))
Yes, that is exactly what I am trying to say. And since I'm not allowed to say
it like that, I was trying to say it using a type synonym parameterised over v
instead.
Why not:
instance Monad ((-) Vect k
On 09/29/2010 09:13 PM, Alexander Solla wrote:
On 09/29/2010 02:15 PM, DavidA wrote:
instance Monad (\v - Vect k (Monomial v))
Yes, that is exactly what I am trying to say. And since I'm not
allowed to say
it like that, I was trying to say it using a type synonym
parameterised over v
David,
Ryan Ingram wrote:
Haskell doesn't have true type functions; what you are really saying
is
instance Monad (\v - Vect k (Monomial v))
Daniel Fischer wrote:
I think there was a theoretical reason why that isn't allowed (making type
inference undecidable? I don't remember, I don't
Hi,
I was going over the Error Handling chapter in RWH and tried out this sample -
Prelude :m Control.Exception
Prelude Control.Exception let x=5 `div` 0
Prelude Control.Exception let y=5 `div` 1
Prelude Control.Exception handle (\_ - putStrLn Text) (print x)
interactive:1:0:
Ambiguous type
On 30 September 2010 15:23, C K Kashyap ckkash...@gmail.com wrote:
Hi,
I was going over the Error Handling chapter in RWH and tried out this sample -
Prelude :m Control.Exception
Prelude Control.Exception let x=5 `div` 0
Prelude Control.Exception let y=5 `div` 1
Prelude Control.Exception
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