* Jonathan Cast wrote:
On 30 Jan 2008, at 7:19 PM, Anton van Straaten wrote:
quickCheck $ x - cos (x + 2*pi) == cos x
Falsifiable, after 2 tests:
-1.0
Test.QuickCheck.quickCheck $ \x - abs (cos x - cos (x + 2*pi)) 0.1
OK, passed 100 tests.
aaltman wrote:
My issues:
1. Are Haskell monads useful in a truly categorical sense?
2. Is Haskell's functor class misnamed?
3. Haskell arrows and Haskell monads have a misleading relationship
1.+2. The stumbling block is probably that Hask has exponentials and
polymorphism. Hence, all
Am 31.01.2008 um 01:23 schrieb [EMAIL PROTECTED]:
3. I believe the documentation stating that Haskell arrows are a
generalization of Haskell monads, but arrows are a categorical
thing too and in that context bear a much more distant relationship
to monads. Does a Haskell arrow have Hask
Bayley, Alistair wrote:
More than one person has posted previously about the flaws and traps of lazy IO. A common
position seems to be don't do lazy IO.
Still, when I was browsing the Haskell' wiki a few days ago, I couldn't
find any proposal to remove lazy I/O or move it into some special
Stephan Friedrichs wrote:
I just uploaded a generalised heap (min-, max- and custom-heaps)
implementation:
http://hackage.haskell.org/cgi-bin/hackage-scripts/package/heap-0.1
Feedback would be appreciated :)
Feedback: I think the HeapPolicy thing is too non-standard. The
canonical way
It seems that algorithms on graphs can be implemented particularly
efficient in low-level languages with pointers and in-place updates. E.g.
topological sort needs only linear time, provided that dereferencing
pointers requires constant time. I could simulate pointer dereferencings
and pointer
Hi,
The EDSL implementation (system design) I'm working on would really
benefit from an implementation of fixed-sized vectors.
I thought this would be a generally desired ADT but it turned out I
wasn't able to find an implementation.
I was thinking about using datatype algebra plus GADTs to
On Thu, 31 Jan 2008, Alfonso Acosta wrote:
The EDSL implementation (system design) I'm working on would really
benefit from an implementation of fixed-sized vectors.
I thought this would be a generally desired ADT but it turned out I
wasn't able to find an implementation.
I was thinking
Wasn't there a Linux file system (possibly a FUSE user-space one) that
worked on writable CDs? IIRC it worked by marking the previous copy of
the file as erased, and writing a new copy.
On Wed, 2008-01-30 at 23:05 -0500, [EMAIL PROTECTED]
wrote:
PS: I would love to see an immutable filesystem
Dear Community.
I have recently read Joel Koerwer's posting how to evaluate a function
of type (a-a-...-a-a), taking the arguments from a list
(http://haskell.org/pipermail/haskell-cafe/2006-October/018658.html).
Therefore, he introduced a function multApply:
multApply :: (a-a-...-a-a) -
Am Donnerstag, 31. Januar 2008 12:02 schrieb Alfonso Acosta:
Hi,
The EDSL implementation (system design) I'm working on would really
benefit from an implementation of fixed-sized vectors.
I thought this would be a generally desired ADT but it turned out I
wasn't able to find an
On Jan 31, 2008 3:03 PM, Wolfgang Jeltsch [EMAIL PROTECTED] wrote:
Hello Fons,
interestingly, it occured to me yesterday that the graphics part of Grapefruit
would benefit from fixed sized vectors. I think we should implement some
small Cabal package which just provides this and upload it to
Hello,
I wondered, why not take an n-tuple of arguments s.t.
multApply' :: (a1-a2-...-an-o) - (a1,(a2,(...(an,o)...))) - o
I'm not sure what you're trying to do here. Why is there an o in the
argument? Also, do you really mean the number of arguments expected to
match the number of
On Jan 31, 2008 5:07 AM, Gary Bickford [EMAIL PROTECTED] wrote:
Wasn't there a Linux file system (possibly a FUSE user-space one) that
worked on writable CDs? IIRC it worked by marking the previous copy of
the file as erased, and writing a new copy.
Probably you're thinking of layering a
Derek Elkins wrote:
On Wed, 2008-01-30 at 22:19 -0500, Anton van Straaten wrote:
...
We discover a function called, say, cos, probably by guessing it's
name, run a very small number of simple tests on it, see the answers we
expect, and decide that it's the function we want. Does anyone want
On Thu, 31 Jan 2008, Anton van Straaten wrote:
Derek Elkins wrote:
Arguably, this
-is- more defensible on a safety/correctness grounds than reading the
documentation. Documentation can be out of date or wrong or right but
the implementation is wrong. So it comes down to a matter of
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of
Jean-Philippe Bernardy
* homepage: http://haskell.org/haskellwiki/Yi
Took a quick look around and saw this:
* GTK frontend works in Win32
So Yi works on Windows? hs-plugins was broken for Windows for a while,
so I'm
I wondered, why not take an n-tuple of arguments s.t.
multApply' :: (a1-a2-...-an-o) - (a1,(a2,(...(an,o)...))) -
o
I'm not sure what you're trying to do here. Why is there an o in the
argument? Also, do you really mean the number of arguments expected to
match the number of
FIRST CALL FOR PAPERS
Second Workshop on
Programming Languages for Mechanized Mathematics
(PLMMS 2008)
http://events.cs.bham.ac.uk/cicm08/workshops/plmms/
As part of CICM /
Henning Thielemann wrote:
On Thu, 31 Jan 2008, Anton van Straaten wrote:
Derek Elkins wrote:
Arguably, this
-is- more defensible on a safety/correctness grounds than reading the
documentation. Documentation can be out of date or wrong or right but
the implementation is wrong. So it comes
Adam Langley agl at imperialviolet.org writes:
On Jan 31, 2008 5:07 AM, Gary Bickford garyb at fxt.com wrote:
Wasn't there a Linux file system (possibly a FUSE user-space one) that
worked on writable CDs? IIRC it worked by marking the previous copy of
the file as erased, and writing a
On Thu, 2008-01-31 at 15:23 +, Bayley, Alistair wrote:
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of
Jean-Philippe Bernardy
* homepage: http://haskell.org/haskellwiki/Yi
Took a quick look around and saw this:
* GTK frontend works in Win32
So Yi works on
On Thu, 31 Jan 2008, Alfonso Acosta wrote:
On Jan 31, 2008 3:03 PM, Wolfgang Jeltsch [EMAIL PROTECTED] wrote:
Hello Fons,
interestingly, it occured to me yesterday that the graphics part of
Grapefruit
would benefit from fixed sized vectors. I think we should implement some
small
On 31 Jan 2008, at 1:23 AM, Reinier Lamers wrote:
Bayley, Alistair wrote:
More than one person has posted previously about the flaws and
traps of lazy IO. A common position seems to be don't do lazy IO.
Still, when I was browsing the Haskell' wiki a few days ago, I
couldn't find any
From: Thomas Schilling [mailto:[EMAIL PROTECTED]
So Yi works on Windows? hs-plugins was broken for Windows
for a while,
so I'm wondering if this has been fixed too. Does Yi use
hs-plugins, or
does it go straight down to ghc? (looking at the yi.cabal
file seems to
indicate no
On 2008-01-22, David Roundy [EMAIL PROTECTED] wrote:
We are happy to announce the third prerelease version of darcs 2! Darcs 2
David,
I'm very happy to see this, and will be trying it out today!
I have one concern though, and it's a big one. On your DarcsTwo page,
it says:
Darcs get is now
On Thu, Jan 31, 2008 at 09:47:06AM -0600, John Goerzen wrote:
On 2008-01-22, David Roundy [EMAIL PROTECTED] wrote:
We are happy to announce the third prerelease version of darcs 2! Darcs 2
I'm very happy to see this, and will be trying it out today!
Great! I do recommend that you try the
I remember that type-level arithmetic is already implemented somewhere,
certainly more than once, but certainly seldom in a nicely packaged form.
erm, here
http://www.haskell.org/haskellwiki/Type_arithmetic
Yep, there seem to be a few implementations around (decimal, binary,
peano) but
Is YI also an IDE for creating Haskell code? I guess it's not, it's just a
text editor right?
I mean, if it talks to GHC directly, it could neatly take over some tricks used
in Visual Haskell (on the fly type inference, good completion, etc), only much
much easier (without the COM layer,
Hello Henning,
Thursday, January 31, 2008, 5:49:23 PM, you wrote:
I remember that type-level arithmetic is already implemented somewhere,
certainly more than once, but certainly seldom in a nicely packaged form.
one more:
darcs get --partial --tag '0.1'
winds up having a write cache, which is mutable in practice. The
interesting thing is that the block's location is the cryptographic
hash of its contents, which leads to all sorts of neat properties (as
well as requiring immutability).
That's interesting. When I developed a version control
Even though you cannot dive into this matter now, maybe when you get
time you can update your blog with an explicit embedding of Haskell
monads and arrows in your Thrist construction. Concrete examples will
help me (and probably others) more quickly see the novelty, increased
generality, and
Look at
http://sneezy.cs.nott.ac.uk/fun/feb-07/jeremy-slides.pdf
and
http://article.gmane.org/gmane.comp.lang.haskell.cafe/27062
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On Thu, 2008-01-31 at 09:46 -0500, Anton van Straaten wrote:
Derek Elkins wrote:
On Wed, 2008-01-30 at 22:19 -0500, Anton van Straaten wrote:
...
We discover a function called, say, cos, probably by guessing it's
name, run a very small number of simple tests on it, see the answers we
On Jan 31, 2008 5:47 PM, Bulat Ziganshin [EMAIL PROTECTED] wrote:
one more:
darcs get --partial --tag '0.1' http://www.eecs.tufts.edu/~rdocki01/typenats/
Thanks for the link, I had already checked this library, but using a
binary representation has the same problem as using peano numbers,
error
Hello Peter,
Thursday, January 31, 2008, 8:01:36 PM, you wrote:
files with different content generating the same hash)... My
intuition told me that the odds of two cryptographic hashes (on
meaningful content) colliding was much less than the earth being
destroyed by an asteroid... But this
Depending on which hash you use you can get upwards of document
hask keys won't collide before the heat-death of the universe.
There is of course a lot more to it than that. Google around
about hashing, cryptography, and cryptographic hash functions.
There are many good websites that will go
On 1/31/08, Peter Verswyvelen [EMAIL PROTECTED] wrote:
winds up having a write cache, which is mutable in practice. The
interesting thing is that the block's location is the cryptographic
hash of its contents, which leads to all sorts of neat properties (as
well as requiring immutability).
On Jan 31, 2008, at 9:15 AM, David Roundy wrote:
On Thu, Jan 31, 2008 at 09:47:06AM -0600, John Goerzen wrote:
I have one concern though, and it's a big one. On your DarcsTwo
page,
it says:
Darcs get is now much faster, and always operates in a lazy
fashion, meaning that patches are
On Thu, Jan 31, 2008 at 11:51:10AM -0700, zooko wrote:
I would suggest that strict get should be the default and lazy is a
command-line option.
Okay. I'm convinced, and am pushing a patch to do this.
--
David Roundy
Department of Physics
Oregon State University
On 2008.01.31 16:27:05 -, Bayley, Alistair [EMAIL PROTECTED] scribbled
0.7K characters:
From: Thomas Schilling [mailto:[EMAIL PROTECTED]
So Yi works on Windows? hs-plugins was broken for Windows
for a while,
so I'm wondering if this has been fixed too. Does Yi use
hs-plugins,
On Jan 31, 2008, at 5:39 AM, Henning Thielemann wrote:
It seems that algorithms on graphs can be implemented particularly
efficient in low-level languages with pointers and in-place updates.
E.g.
topological sort needs only linear time, provided that dereferencing
pointers requires
droundy:
On Thu, Jan 31, 2008 at 11:51:10AM -0700, zooko wrote:
I would suggest that strict get should be the default and lazy is a
command-line option.
Okay. I'm convinced, and am pushing a patch to do this.
Great!
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On 2008-01-31, David Roundy [EMAIL PROTECTED] wrote:
way to pull down everything that could possibly be needed? But from
the way the wiki page is sounded, it doesn't sound that way.
Running darcs check, darcs changes -s or darcs changes foobar for
instance would ensure that you've got a
Am Donnerstag, 31. Januar 2008 18:30 schrieb Dominic Steinitz:
Look at
http://sneezy.cs.nott.ac.uk/fun/feb-07/jeremy-slides.pdf
This is essentially what I had in mind. While Oleg’s implementation needs
a “thrusted core”, the GADT solution doesn’t.
It would be interesting to combine GADTs
Am Donnerstag, 31. Januar 2008 15:15 schrieben Sie:
[…]
I think we should base our implementation on Oleg's (for which we need
his permission).
Do you know whether Oleg has released his code under an open source license?
If he had, we wouldn’t need his permission. I’m not sure whether we
Is it possible to automatically derive instances of
Prettyhttp://haskell.org/ghc/docs/latest/html/libraries/haskell-src/Language-Haskell-Pretty.html?
If no, what do most do when it comes to pretty-printing large data types?
Thanks,
Greg
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Haskell-Cafe
Am 31.01.2008 um 18:13 schrieb Dan Weston:
Even though you cannot dive into this matter now, maybe when you
get time you can update your blog with an explicit embedding of
Haskell monads and arrows in your Thrist construction. Concrete
examples will help me (and probably others) more
Hmmm, not sure what you asking for. If you have a monad instance Set a
that has Eq a attached, this
already would do what you want, no? An example would help me to
understand...
Sorry, I meant uppercase (and got the constraint wrong anyway). I meant
that Ord a = Set a was a monad (lowercase
Has anyone written anything on the use of FP (e.g. point free style) in linear
algebra problems?
--
Dr Jon D Harrop, Flying Frog Consultancy Ltd.
http://www.ffconsultancy.com/products/?e
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Hello Ryan,
I hope, it’s okay to forward your message to the list:
Date: Freitag, 1. Februar 2008 01:41
From: Ryan Ingram [EMAIL PROTECTED]
To: Wolfgang Jeltsch [EMAIL PROTECTED]
This representation is not exactly the same when you include _|_.
For example:
data None -- only _|_ /
On Thu, Jan 31, 2008 at 7:11 PM, Jon Harrop [EMAIL PROTECTED] wrote:
Has anyone written anything on the use of FP (e.g. point free style) in
linear
algebra problems?
I'm not sure how relevant this is to you, but John Backus wrote
foundationally on it and related topics.
On Thu, Jan 31, 2008 at 03:00:15PM -0800, Greg Fitzgerald wrote:
Is it possible to automatically derive instances of
Prettyhttp://haskell.org/ghc/docs/latest/html/libraries/haskell-src/Language-Haskell-Pretty.html?
If no, what do most do when it comes to pretty-printing large data types?
It
Wolfgang Jeltsch wrote:
Well, the representation (D1,D2,D9) might be considered more readable. It has
the disadvantage of a fixed maximum size for the numbers. Which takes me to
a point I had already considered some time ago: Wouldn’t it be good if we had
just a type
data Pair val1
You could solve it this way:
data PairL a b = PairL a !b
where (a,b,c) is syntactic sugar for
PairL a (PairL b (PairL c ()))
There are still potential efficiency issues, although this could be
worked out in the compiler; right now it's a single operation to get
from a tuple to any member,
Hello,
Today on #haskell, resiak was asking about a clean way to write the
function which allocates an array of CStrings using withCString and
withArray0 to produce a new with* style function. I came up with the
following:
nest :: [(r - a) - a] - ([r] - a) - a
nest xs = runCont (sequence (map
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