minh thu noteed at gmail.com writes:
http://www.haskell.org/haskellwiki/Haddock/FAQ
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Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
Hi
Does GHC specialize map? If it doesn't, then hand crafted version
could be faster.
GHC doesn't specialize map, and a hand-crafted one could be faster -
but you then wouldn't get foldr/build fusion. In general HLint tries
to make the code prettier, but sometimes you will need to deviate
Don Stewart wrote:
marlowsd:
Neal Alexander wrote:
Thomas DuBuisson wrote:
It seems like we could get some priority based scheduling (and still
be slackers) if we allow marked green threads to be strictly
associated with a specific OS thread (forkChildIO?).
I think you want the
Neal Alexander wrote:
Simon Marlow wrote:
Neal Alexander wrote:
Thomas DuBuisson wrote:
It seems like we could get some priority based scheduling (and
still
be slackers) if we allow marked green threads to be strictly
associated with a specific OS thread (forkChildIO?).
I think
Dear Haskellers,
I would like to forward this announcement on behalf of Petr Ročkai
(the current darcs Release Manager).
Darcs 2.2 is scheduled for release in 2009-01-15, only three days from
now! This is the first of our biannual time-based releases. We hope
you'll like it, and to help us
I've found the pico second accuracy useful in working with 'rate
equivalent' real time systems. Systems where the individual timings
(their jitter) is not critical but the long term rate should be
accurate - the extra precision helps with keeping the error
accumulation under control.
Aren't Doubles evil? Integer is a nice type, Haskell
filosofy compliant. Doubles are not CDoubles, IEEE, infinite
precision or anything long term meaninfull. (Warning:
non-expert opinion.)
I've found the pico second accuracy useful in working with 'rate
equivalent' real time systems. Systems
Neil Davies wrote:
I've found the pico second accuracy useful in working with 'rate
equivalent' real time systems. Systems where the individual timings
(their jitter) is not critical but the long term rate should be accurate
- the extra precision helps with keeping the error accumulation under
patients, I wanted to be sure not to save wrong
information. It wouldn't matter if the clock is
saying we are on XVII century, as long as 10 seconds
would never be 10.1.
What are the interval durations you need to measure?
Since they are from equipment, what is the spec?
I read from serial
Hi all,
I'm trying to build the Sdf2Haskell library. However, I've got the following problem:
Making all in generatorlocate: illegal option -- nusage: locate [-0Scims] [-l limit] [-d database] pattern ...default database: `/var/db/locate.database' or $LOCATE_PATHmake Sdf.tbllocate: illegal option
I repeatedly encounter the following versioning problem on Hackage:
There is a package A with version 1.0.
I upload a package B which imports A.
Thus B is bound to A-1.0
Now a new version of A is uploaded, say 1.0.1.
then I upload package C which depends both on A and B.
However C is bound to
On Mon, 12 Jan 2009, ChrisK wrote:
Lennart is right that 1 picosecond accuracy is absurd compared to all
the jitters and drifts in anything but an actual atomic clock in your
room. But since CPUs tick faster than nanosecond the CPUTime needs
better than 1 nanosecond granularity. I agree
On Mon, 12 Jan 2009, Jan Christiansen wrote:
Hi,
Although it seems to be overkill for a single module - How about a
cabalized version on Hackage and a darcs repository? It would simplify
using and updating it.
I am not sure whether this would be a good idea. The original version makes a
Forwarding to Haskell Cafe per Eric's suggestion.
Begin forwarded message:
Date: Sun, 11 Jan 2009 23:01:31 -0600
From: Rob Hoelz r...@hoelzro.net
To: darcs-de...@darcs.net
Subject: [darcs-devel] Inferred type is less polymorphic than
expected and type witnesses
Hello again, Darcs users and
On Mon, 2009-01-12 at 13:21 +0100, Henning Thielemann wrote:
I repeatedly encounter the following versioning problem on Hackage:
There is a package A with version 1.0.
I upload a package B which imports A.
Thus B is bound to A-1.0
Now a new version of A is uploaded, say 1.0.1.
then I upload
Neil Mitchell escribió:
Hi
Does GHC specialize map? If it doesn't, then hand crafted version
could be faster.
GHC doesn't specialize map, and a hand-crafted one could be faster -
but you then wouldn't get foldr/build fusion. In general HLint tries
to make the code prettier, but
On Mon, 2009-01-12 at 01:02 +0100, Lennart Augustsson wrote:
Does GHC specialize map? If it doesn't, then hand crafted version
could be faster.
No because the current definition are recursive and ghc cannot inline
recursive functions.
map :: (a - b) - [a] - [b]
map _ [] = []
map f (x:xs)
On Mon, 12 Jan 2009, Duncan Coutts wrote:
On Mon, 2009-01-12 at 01:02 +0100, Lennart Augustsson wrote:
Does GHC specialize map? If it doesn't, then hand crafted version
could be faster.
No because the current definition are recursive and ghc cannot inline
recursive functions.
map :: (a -
On Sun, 2009-01-11 at 17:43 -0800, Patrick Perry wrote:
The touchForeignPtr is there to keep the garbage collector from
deallocating the memory before we have a chance to read 'e'. My
question is the following:
Is the `seq` on `io` necessary (from a safety standpoint)? Or am I
just
Hi
No because the current definition are recursive and ghc cannot inline
recursive functions.
map :: (a - b) - [a] - [b]
map f = go
where
go [] = []
go (x:xs) = f x : go xs
Then the map can be inlined at the call site and the 'f' inlined into
the body of 'go'.
Maybe HLint
On Mon, 2009-01-12 at 15:06 +0100, Henning Thielemann wrote:
It has to be manually transformed into a version that is not recursive
at the top level:
map :: (a - b) - [a] - [b]
map f = go
where
go [] = []
go (x:xs) = f x : go xs
Then the map can be inlined at the
On Mon, 12 Jan 2009, Neil Mitchell wrote:
Hi
No because the current definition are recursive and ghc cannot inline
recursive functions.
map :: (a - b) - [a] - [b]
map f = go
where
go [] = []
go (x:xs) = f x : go xs
Then the map can be inlined at the call site and the 'f' inlined
On Jan 12, 2009, at 9:01 AM, Duncan Coutts wrote:
No because the current definition are recursive and ghc cannot inline
recursive functions.
map :: (a - b) - [a] - [b]
map _ [] = []
map f (x:xs) = f x : map f xs
It has to be manually transformed into a version that is not recursive
at
Patrick Perry wrote:
I have the following code:
IOVector n e = IOVector !ConjEnum !Int (ForeignPtr e)! (Ptr e)! Int!
newtype Vector n e = IOVector n e
unsafeAtVector :: Vector n e - Int - e
unsafeAtVector (Vector (IOVector c _ f p inc)) i =
let g = if c == Conj then conjugate else id
2009/1/12 Jan-Willem Maessen jmaes...@alum.mit.edu:
On Jan 12, 2009, at 9:01 AM, Duncan Coutts wrote:
No because the current definition are recursive and ghc cannot inline
recursive functions.
Then the map can be inlined at the call site and the 'f' inlined into
the body of 'go'.
Some questions first:
What's the type of this function supposed to be?
What's the type of unsafeCompare?
How is the data type with NilFL and :: defined?
-- ryan
On Mon, Jan 12, 2009 at 5:43 AM, Rob Hoelz r...@hoelzro.net wrote:
Forwarding to Haskell Cafe per Eric's suggestion.
Begin
I should've included these when I forwarded it, but that was pre-coffee
today. =P
class MyEq p where
unsafeCompare :: p C(a b) - p C(c d) - Bool
-- more stuff
data FL a C(x z) where
(::) :: a C(x y) - FL a C(y z) - FL a C(x z)
NilFL :: FL a C(x x)
data (a1 : a2) C(x y) = FORALL(z) (a1
ndmitchell:
Hi
Does GHC specialize map? If it doesn't, then hand crafted version
could be faster.
GHC doesn't specialize map, and a hand-crafted one could be faster -
but you then wouldn't get foldr/build fusion. In general HLint tries
to make the code prettier, but sometimes you will
dons:
ndmitchell:
Hi
Does GHC specialize map? If it doesn't, then hand crafted version
could be faster.
GHC doesn't specialize map, and a hand-crafted one could be faster -
but you then wouldn't get foldr/build fusion. In general HLint tries
to make the code prettier, but
On Mon, Jan 12, 2009 at 6:47 PM, Max Bolingbroke
batterseapo...@hotmail.com wrote:
GHC should indeed be doing so. I'm working (on and off) to work out
some suitable heuristics and put the transformation into ghc -O2.
There are a few wrinkles that still need sorting out, but preliminary
Hi all, I'm trying to build a library whose configuration process requires the data, util, and lang packages. I guess that these are *deprecated* packages, since the library is said to be ghc 6.4.1 compliant.
Which packages should I use instead?
Where can I find such packages (if they are not
On Jan 12, 2009, at 12:47 PM, Max Bolingbroke wrote:
2009/1/12 Jan-Willem Maessen jmaes...@alum.mit.edu:
On Jan 12, 2009, at 9:01 AM, Duncan Coutts wrote:
No because the current definition are recursive and ghc cannot
inline
recursive functions.
Then the map can be inlined at the
rodrigo.bonifacio:
Hi all, I'm trying to build a library whose configuration process requires
the data, util, and lang packages. I guess that these are *deprecated*
packages, since the library is said to be ghc 6.4.1 compliant.
Which packages should I use instead?
Where can
On Mon, 12 Jan 2009 19:43:00 +0100
Bas van Dijk v.dijk@gmail.com wrote:
On Mon, Jan 12, 2009 at 6:47 PM, Max Bolingbroke
batterseapo...@hotmail.com wrote:
GHC should indeed be doing so. I'm working (on and off) to work out
some suitable heuristics and put the transformation into ghc
Thanks for your help, Duncan.
On Jan 12, 2009, at 6:10 AM, Duncan Coutts wrote:
Do the (ForeignPtr e) and the (Ptr e) point to the same thing? They
appear to be related because you dereference p but touch f.
It used to be the ForeignPtr was slower to dereference than a Ptr
and so
caching
On Mon, 12 Jan 2009, Robin Green wrote:
I tend to use Control.Monad.Fix.fix (which actually has nothing to do
with monads, despite the package name)
That's why it is also available from Data.Function now:
http://www.haskell.org/ghc/docs/latest/html/libraries/base/Data-Function.html
On Mon, Jan 12, 2009 at 6:06 PM, Robin Green gree...@greenrd.org wrote:
The fix-style equivalent to your repeat above, would be something like
this:
repeat x = fix $ \me - x ::: me
Interesting.
Your repeat and mine are compiled to the same code:
Data.Stream.repeat :: forall a_aVi.
Please correct me if I'm wrong in any of the reasoning below.
Haskell provides the ability the perform partial application on the
rightmost arguments.
I learned from some pretty smart guys that partial application cannot be
emulated with lambas, because they behave differently operationally, e.g.
Do you have any benchmarks comparing dictionaries against Map ByteString
Int, or Map String Int?
-- Don
wren:
-- bytestring-trie 0.1.4
Another release for efficient finite maps from (byte)strings to
How about using lets?
2009/1/12 Peter Verswyvelen bugf...@gmail.com:
e = trace e
op = (+)
a1 = let f = (op (e 1)) in (f 10, f 100)
a2 = let f = (\x - op (e 1) x) in (f 10, f 100)
a1 and a2 are operationally not the same: a1 will evaluate (e 1) once, a2
a3 = let f = (let y = e 1 in (\x - op
On Mon, Jan 12, 2009 at 8:33 PM, Felipe Lessa felipe.le...@gmail.comwrote:
z1' = let f = (let y1 = e1 1; y2 = e2 2 in (\x - op2 y2 y1 x)) in (f 3, f
4)
oooh! sweet! I didn't think of that. many thanks
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Haskell-Cafe mailing list
Neil Mitchell wrote:
Hi Andrew,
HLint will automatically detect if you should have used a map, a foldr
or a foldl and suggest how to change your code. In the GHC, darcs and
Hoogle code bases there are no obvious map-like functions, which is a
good sign :-)
...What an intriguing
On Sun, 11 Jan 2009, Duncan Coutts wrote:
We really need to upgrade the whole thing. Not an easy job given the
range of stuff being run on there by lots of different people.
Btw. is there a simple way to download all the Wiki content?
___
On Mon, 12 Jan 2009, Andrew Coppin wrote:
Off the top of my head, try this:
convert b 0 = []
convert b n = n `mod` b : convert b (n `div` b)
(Takes a number and yields the radix-B representation of it. Backwards.)
convert b = unfoldr (\n - if n 0 then Just (n `mod` b, n `div` b) else
Apfelmus, Heinrich schrieb:
Ertugrul Soeylemez wrote:
Let me tell you that usually 90% of my code is
monadic and there is really nothing wrong with that. I use especially
State monads and StateT transformers very often, because they are
convenient and are just a clean combinator frontend to
Hi,
I¹ve been reading the Monads aren¹t evil posts with interest I¹m a 2nd
week Haskell newbie and I¹m doing my best to use them where (I hope) it is
appropriate. Typically I¹m writing my code out without using Monads
(normally using list recursion), and then when I get them working, I delve
Ertugrul Soeylemez schrieb:
Apfelmus, Heinrich apfel...@quantentunnel.de wrote:
The insistence on avoiding monads by experienced Haskellers, in
particular on avoiding the IO monad, is motivated by the quest for
elegance.
The IO and other monads make it easy to fall back to imperative
Hi all,
If you are interested in helping out with the haskell platform project
then we invite you to subscribe to the haskell-platform mailing list.
http://projects.haskell.org/cgi-bin/mailman/listinfo/haskell-platform
This mailing list is for discussing practical stuff. We expect to
discuss
2009/1/12 Phil pbeadl...@mail2web.com:
Hi,
I've been reading the Monads aren't evil posts with interest – I'm a 2nd
week Haskell newbie and I'm doing my best to use them where (I hope) it is
appropriate. Typically I'm writing my code out without using Monads
(normally using list recursion),
Here's a minimal bit of code that gives you the error:
data FL p x z where
ConsFL :: p x y - FL p y z - FL p x z
NilFL :: FL p x x
data GTE a1 a2 x z where
GTE :: a1 x y - a2 y z - GTE a1 a2 x z
ccwo (ConsFL x xs) (ConsFL y ys) =
case ccwo xs ys of
GTE nx ny -
Hi all,
I'm going to start a project where I'll have to do some data analysis
(statistics about product orders) based on database entries; it will
mostly be some very basic stuff like grouping by certain rules and
finding averages as well as summing up and such. It will however be
more than
d:
Hi all,
I'm going to start a project where I'll have to do some data analysis
(statistics about product orders) based on database entries; it will
mostly be some very basic stuff like grouping by certain rules and
finding averages as well as summing up and such. It will however be
On Mon, Jan 12, 2009 at 12:57:57PM -0800, Judah Jacobson wrote:
I'm pleased to announce the first release of ghci-haskeline. This
package uses the GHC API to reimplement ghci with the Haskeline
library as a backend. Haskeline is a library for line input in
command-line programs, similar to
Haskeline is designed to remove the readline dependency, because Windows does
not have readline. So rlwrap is useless there.
Andrew Hunter wrote:
On Mon, Jan 12, 2009 at 12:57:57PM -0800, Judah Jacobson wrote:
I'm pleased to announce the first release of ghci-haskeline. This
package uses
* Andrew Hunter ahun...@cs.hmc.edu [2009-01-12 13:41:03-0800]
On Mon, Jan 12, 2009 at 12:57:57PM -0800, Judah Jacobson wrote:
I'm pleased to announce the first release of ghci-haskeline. This
package uses the GHC API to reimplement ghci with the Haskeline
library as a backend. Haskeline
Hi all,
I'm trying to build a library that has the following code:
hasTypeOf (TermRep (dx,_,_)) (x::t) = ((fromDynamic dx)::Maybe t)
When I try to compile with ghc-6.8.3 I got the following error:
../../StrategyLib/models/drift-default//TermRep.hs:63:30: A pattern type signature cannot bind
On Mon, Jan 12, 2009 at 10:11:19PM +, ChrisK wrote:
Haskeline is designed to remove the readline dependency, because Windows
does not have readline. So rlwrap is useless there.
Ah, I hadn't considered Windows support--that makes sense. Thanks,
that answers my questions.
AHH
On Mon, 2009-01-12 at 19:43 +0100, Bas van Dijk wrote:
On Mon, Jan 12, 2009 at 6:47 PM, Max Bolingbroke
batterseapo...@hotmail.com wrote:
GHC should indeed be doing so. I'm working (on and off) to work out
some suitable heuristics and put the transformation into ghc -O2.
There are a few
Tony Finch wrote:
The FreeBSD kernel uses a 64+64 bit fixed point type to represent time,
where the integer part is a normal Unix time_t. The fractional part is
64 bits wide in order to be able to represent multi-GHz frequencies
precisely.
multi-GHz being a euphemism for 18.45*10^9 GHz, over
On Mon, 2009-01-12 at 20:23 +0100, Bas van Dijk wrote:
On Mon, Jan 12, 2009 at 6:06 PM, Robin Green gree...@greenrd.org wrote:
The fix-style equivalent to your repeat above, would be something like
this:
repeat x = fix $ \me - x ::: me
Interesting.
The definition of fix is small and
Gtk2Hs 0.9.13 has an annoying bug on Windows that makes it impossible to run
via GHCi.
So to see if the latest development version works better, I tried to build
it on Windows using GHC 6.10.1, but I failed to do so with both MSYS and
Cygwin.
Does anybody know how to build it on Windows?
Thanks,
On Sun, 2009-01-11 at 10:44 +0100, Apfelmus, Heinrich wrote:
Ertugrul Soeylemez wrote:
Let me tell you that usually 90% of my code is
monadic and there is really nothing wrong with that. I use especially
State monads and StateT transformers very often, because they are
convenient and are
On Mon, Jan 12, 2009 at 2:16 PM, Daniel Kraft d...@domob.eu wrote:
This was probably my fault at that time, because I surely did something
completely wrong for the Haskell style. However, I fear I could run into
problems like that in the new project, too. So I want to ask for your
opinions,
On Tue, 2009-01-13 at 00:09 +0100, Peter Verswyvelen wrote:
Gtk2Hs 0.9.13 has an annoying bug on Windows that makes it impossible
to run via GHCi.
So to see if the latest development version works better, I tried to
build it on Windows using GHC 6.10.1, but I failed to do so with both
On Mon, 12 Jan 2009 21:04:35 +0100 (CET)
Henning Thielemann lemm...@henning-thielemann.de wrote:
On Mon, 12 Jan 2009, Andrew Coppin wrote:
Off the top of my head, try this:
convert b 0 = []
convert b n = n `mod` b : convert b (n `div` b)
(Takes a number and yields the radix-B
I just tried getCPUTime on Windows and it seems to tick really slow, about
10 times per second or so. Actually it changes every 1560010
picoseconds, so about 15600 microseconds, which is indeed the interval at
which Windows updates its tick count.
So anyway a lot of room to go to the
Andrew Coppin wrote:
Günther Schmidt wrote:
Hi Bulat,
I do :), but I was amazed that there was no response to a post with,
what I thought, would be a rather common problem for an application
developer. That post was about writing to an MS-Access database via
HDBC-ODBC, which fails. When
Hi,
I'm trying to write a small module for conveniently writing functions
that can return any of a finite number of types. That is, I'd like to
be able to write something like
foo :: StringOrInt t = String - IO t
This is pretty easy to do if I hard-code the classes as above, but I
run into
Thanks Minh - I've updated my code as you suggested. This looks better than
my first attempt!
Is it possible to clean this up any more? I find:
( (), (Double, Word64) )
a bit odd syntactically, although I understand this is just to fit the type
to the State c'tor so that we don't have to
On Mon, Jan 12, 2009 at 5:56 PM, Stephen Hicks sd...@cornell.edu wrote:
-- This instance definition is broken...
instance (Monad m,Pick (a,b) c) = Pick (m a,m b) (m c) where
pick (ma,mb) = do { a - ma; b - mb; return $ pick (a,b) }
First, and I know these types of comments are generally
On Mon, Jan 12, 2009 at 6:34 PM, Phil pbeadl...@mail2web.com wrote:
-- Monad Implementation
evolveUnderlying :: (Double, Word64) - ( (), (Double, Word64) )
evolveUnderlying (stock, state) = ( (), ( newStock, newState ) )
where
newState = ranq1Increment state
newStock = stock * exp
On Mon, Jan 12, 2009 at 8:34 PM, Phil pbeadl...@mail2web.com wrote:
Thanks Minh - I've updated my code as you suggested. This looks better than
my first attempt!
Is it possible to clean this up any more? I find:
( (), (Double, Word64) )
a bit odd syntactically, although I understand this
Hi all. Under I have some old code that broke under ghc 6.10.1.
Under (6.6.1), 6.8.1 (and I think 6.8.2), this compiles.
import Prelude hiding(catch)
import Control.Concurrent
import Control.Exception(catch,throw,evaluate)
async :: IO a - IO (MVar a)
async ioa = do
mVar - newEmptyMVar
Hi,
a new release of the 'json' package is now available via hackage,
version 0.4.1
http://hackage.haskell.org/cgi-bin/hackage-scripts/package/json
[no claims that it represents rocket science, but a number of downstream
codebases depend on this package for their operation, hence the
Don Stewart wrote:
Do you have any benchmarks comparing dictionaries against Map ByteString
Int, or Map String Int?
I haven't personally run them, but Mark Wotton has compared
[(ByteString,Int)] vs (Map ByteString Int) vs (Trie Int) version 0.1.1
or 0.1.2 and using data from
On Mon, Jan 12, 2009 at 07:14:36PM -0800, Tim Bauer wrote:
Hi all. Under I have some old code that broke under ghc 6.10.1.
Under (6.6.1), 6.8.1 (and I think 6.8.2), this compiles.
import Prelude hiding(catch)
import Control.Concurrent
import Control.Exception(catch,throw,evaluate)
async ::
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