Mark P Jones wrote:
Martin Sulzmann wrote:
We're also looking for (practical) examples of multi-range
functional dependencies
class C a b c | c - a b
Notice that there are multiple (two) parameters in the range of the FD.
It's tempting to convert the above to
class C a b c | c - a, c - b
Hello Alexis,
Thursday, April 17, 2008, 9:21:16 AM, you wrote:
i'm having some trouble 'getting' functional dependencies in the Haskell
ghc 6.8 manual contains good introduction into FDs
--
Best regards,
Bulatmailto:[EMAIL PROTECTED]
Martin Sulzmann wrote:
Mark P Jones wrote:
In fact, the two sets of dependencies that you have given here are
provably equivalent, so it would be decidedly odd to have a type
improvement system that distinguishes between them.
Based on the FD-CHR formulation, for the single-range FD
On Thu, Apr 17, 2008 at 03:21:16PM +1000, Alexis Hazell wrote:
Hi all,
i'm having some trouble 'getting' functional dependencies in the Haskell
context (although my understanding of them in the context of relational
database theory isn't that great either). Could someone please point me
to
On 16/04/2008, at 22:15, Graham Fawcett wrote:
Hi folks, I'm a newbie, so please forgive any terminological mistakes.
I've been using Shim in Emacs with great success, but there's one
issue I've encountered, and I don't know if it's configuration problem
or something fundamental. Consider a
hackageDB has a substantial sample of code these days, which is handy
for questions like this.
Thanks, Ross. These examples are perfect!
Cheers,
Tom
--
Tom Schrijvers
Department of Computer Science
K.U. Leuven
Celestijnenlaan 200A
B-3001 Heverlee
Belgium
tel: +32 16 327544
e-mail: [EMAIL
Not so long ago, I had difficulties to understand functional dependecies.
Due to the (sometimes well-grounded) prejudgement of considering
research papers as an unfriendly and obscure source of information, I
stupidly ruled out reading Mark P Jones original paper. Then I learned
I was totally
Sittampalam, Ganesh wrote:
Martin Sulzmann wrote:
Mark P Jones wrote:
In fact, the two sets of dependencies that you have given here are
provably equivalent, so it would be decidedly odd to have a type
improvement system that distinguishes between them.
Based on the
Hi folks,
Over at
http://hackage.haskell.org/packages/archive/MissingH/1.0.1.2/logs/failure/ghc-6.8
the build has failed in the Hackage step with this output:
src/Data/BinPacking.hs:78:32:
parse error on input `-- ^ The sizes of bins'
haddock: Failed to check module: Data.BinPacking
That
On Thu, Apr 17, 2008 at 06:45:40AM -0500, John Goerzen wrote:
My local haddock, 0.8, parses this file fine. Is Hackage running and older
version? Could it be upgraded? Or is there something else going on here?
No, it's running haddock 2.1.0, which understands all the GHC
extensions, but is
Hello!
I'm trying to rewrite some FD classes to use associated types instead. The Port
class is for type structures whose leaves have the same type:
class Port p
where
type Leaf p
type Struct p
toList :: p - [Leaf p]
fromList :: [Leaf p] - p
(Leaf p) gives
Why not instead transform single-range FDs into multi-range ones where
possible?
That's a perfectly reasonable assumption and would establish the logical
property that
a - b /\ a - c iff a - b /\ c
for FDs (by definition).
But what about programmers who'd like that
C [x] y z
Sittampalam, Ganesh wrote:
Why not instead transform single-range FDs into multi-range ones where
possible?
That's a perfectly reasonable assumption and would establish the logical
property that
a - b /\ a - c iff a - b /\ c
for FDs (by definition).
On Thu, Apr 17, 2008 at 4:26 AM, pepe [EMAIL PROTECTED] wrote:
On 16/04/2008, at 22:15, Graham Fawcett wrote:
I'd like to be able to tell Shim that 'App' is the root of my project,
and to locate modules from that root. Is this possible?
Shim already does this. All it requires is that
On Thu April 17 2008 7:01:18 am Ross Paterson wrote:
On Thu, Apr 17, 2008 at 06:45:40AM -0500, John Goerzen wrote:
My local haddock, 0.8, parses this file fine. Is Hackage running and
older version? Could it be upgraded? Or is there something else going
on here?
No, it's running
class C a b c | a - b, a - c
instance C a b b = C [a] [b] [b]
Suppose we encounter the constraint C [x] y z
interesting example. splitting improvement into two rules
seems to lose the (b1=b2) constraint that spans both:
[O]
C [x] y z = y=[b1].
C [x] y z = z=[b2].
my first thought was
Graham Fawcett wrote:
I notice in the source for GHC.Handle that certain functions (e.g.
fdToHandle_stat) are in the export list, but are not actually exported
(at least, it seems you cannot import them). What mechanism causes
these functions to be hidden, and are they still accessible in some
I'd like to be able to tell Shim that 'App' is the root of my project,
and to locate modules from that root. Is this possible?
If adding the cabal file does'nt work contact me and we'll try to
reslove this issue. Are you willing to test new versions/ extensions?
Are you already using ghc-6.8 ?
Fraser Wilson wrote:
Good question. I often need to export a name to other modules within the
hierarchy, but without making them visible outside it. I've solved this
problem by giving them funky names and adding a comment, but is there a more
structured way to do this? A quick google hasn't
On Thu, Apr 17, 2008 at 10:38 AM, Bertram Felgenhauer
[EMAIL PROTECTED] wrote:
Graham Fawcett wrote:
I notice in the source for GHC.Handle that certain functions (e.g.
fdToHandle_stat) are in the export list, but are not actually exported
(at least, it seems you cannot import them).
On Thu, Apr 17, 2008 at 10:41 AM, Marc Weber [EMAIL PROTECTED] wrote:
I'd like to be able to tell Shim that 'App' is the root of my project,
and to locate modules from that root. Is this possible?
If adding the cabal file does'nt work contact me and we'll try to
reslove this issue.
It
On Wed, Apr 16, 2008 at 2:33 PM, Bertram Felgenhauer
[EMAIL PROTECTED] wrote:
No. Data.Graph.Inductive.Query.Dominators is just buggy.
[...]
Here's a quick fix:
Thanks! This fixes my problem.
Have you submitted a bug and your patch to the appropriate tracker?
If not, would someone point me
a little more experimentation leaves me confused. consider
[4]
class C a b c | a - b -- , a - c
instance C a b b = C [a] [b] [b]
Hugs:
:t undefined :: C [x] y z = (x,y,z)
undefined :: C [a] [b] c = (a,[b],c)
GHCi:
:t undefined :: C [x] y z = (x,y,z)
undefined :: C [x]
Well Isaac...I became now a little bit smarter then yesterday!!!
I show you the example that I found and on which I´m working with.
File: foo.hs
module Foo where
foreign export ccall foo :: Int - IO Int
foo :: Int - IO Int
foo n = return (length (f n))
f :: Int - [Int]
f 0 = []
f n = n:(f
Common Misunderstandings - HaskellWiki
http://www.haskell.org/haskellwiki/Common_Misunderstandings
I didn't find this one... maybe it should be in a more prominent place?
Things to avoid - HaskellWiki
http://www.haskell.org/haskellwiki/Things_to_avoid
I thought of this but it has more
Hello,
On Wed, Apr 16, 2008 at 11:06 PM, Martin Sulzmann
[EMAIL PROTECTED] wrote:
3) Multi-range FDs
Consider
class C a b c | a - b c
instance C a b b = C [a] [b] [b]
This time it's straightforward.
C [x] y z yields the improvement y = [b] and z = [b]
which then allows us to
Iavor Diatchki wrote:
Hello,
On Wed, Apr 16, 2008 at 11:06 PM, Martin Sulzmann
[EMAIL PROTECTED] wrote:
3) Multi-range FDs
Consider
class C a b c | a - b c
instance C a b b = C [a] [b] [b]
This time it's straightforward.
C [x] y z yields the improvement y = [b] and z = [b]
which
2008/4/17, John Goerzen [EMAIL PROTECTED]:
On Thu April 17 2008 7:01:18 am Ross Paterson wrote:
On Thu, Apr 17, 2008 at 06:45:40AM -0500, John Goerzen wrote:
My local haddock, 0.8, parses this file fine. Is Hackage running and
older version? Could it be upgraded? Or is there
Hi,
(Hi again to those on haskell-cafe, but things have changed since the
other announcement)
A lot of haskell-related projects use the darcs version control system.
Darcs has the nice feature that you can easily submit a patch by e-mail,
usually sent to the project maintainer or a mailing list.
On Thu, Apr 17, 2008 at 4:46 PM, Bertram Felgenhauer
[EMAIL PROTECTED] wrote:
Assuming you're writing a cabal package, you could separate the interface
from the actual implementation:
[..]
HTH,
Magic. Thanks a lot!
cheers,
Fraser.
___
Emping is a utility which derives the shortest rules from a table of
rules. For example, in a list of 8000 different mushrooms, it finds 21
single predicates that determine the mushroom is poisonous, and 23 that
it is edible. But it also finds all combinations of two, three and more
predicates
a little more experimentation leaves me confused. consider
[4]
class C a b c | a - b -- , a - c
instance C a b b = C [a] [b] [b]
Hugs:
:t undefined :: C [x] y z = (x,y,z)
undefined :: C [a] [b] c = (a,[b],c)
GHCi:
:t undefined :: C [x] y z = (x,y,z)
undefined :: C [x] y z =
Hello,
On Thu, Apr 17, 2008 at 10:26 AM, Martin Sulzmann
[EMAIL PROTECTED] wrote:
leads to an instance improvement/instance improvement conflict,
like in the single-range FD case
class D a b | a - b
instance D a a = D [a] [a]
instance D [Int] Char
Sorry to be picky but there is no
Iavor Diatchki wrote:
Hello,
On Thu, Apr 17, 2008 at 10:26 AM, Martin Sulzmann
[EMAIL PROTECTED] wrote:
leads to an instance improvement/instance improvement conflict,
like in the single-range FD case
class D a b | a - b
instance D a a = D [a] [a]
instance D [Int] Char
Sorry
Graham == Graham Fawcett [EMAIL PROTECTED] writes:
Graham Equally glad that it's being supported! Thank you.
Where one can found it?
Few days ago I was told on #haskell that shim is dead :-/
Sincerely,
Gour
--
Gour | Zagreb, Croatia | GPG key: C6E7162D
On Thu, Apr 17, 2008 at 11:32 AM, Denis Bueno [EMAIL PROTECTED] wrote:
On Wed, Apr 16, 2008 at 2:33 PM, Bertram Felgenhauer
[EMAIL PROTECTED] wrote:
No. Data.Graph.Inductive.Query.Dominators is just buggy.
I have one more problem. For the attached graph, the dominators of
the -20 node are
A new version of my raytracer is out. It now supports cones, cylinders,
disks, boxes, and planes as base primitives (previously it only
supported triangles and spheres), as well as transformations of
arbitrary objects (rotate, scale, translate) and the CSG operations
difference and
To reuse a favorite word, I think that any implementation that distinguishes
'a - b, a - c' from 'a - b c' is broken. :)
It does not implement FD, but something else. Maybe this something else is
useful, but if one of the forms is strictly more powerful than the other
then I don't see why you
Your reasoning differs from the usual understanding of a null product (1
or True), as compared to a null sum (0 or False):
the list of nodes for which
*any path* from source to x must touch, i.e., the list of dominators
of x.
Here, any path means all paths, a logical conjunction:
and
2008/4/17 Gour [EMAIL PROTECTED]:
Graham == Graham Fawcett [EMAIL PROTECTED] writes:
Graham Equally glad that it's being supported! Thank you.
Where one can found it?
Few days ago I was told on #haskell that shim is dead :-/
The original, I believe:
http://mapcar.org/haskell/shim/
On Thu, Apr 17, 2008 at 5:52 PM, Dan Weston [EMAIL PROTECTED] wrote:
Your reasoning differs from the usual understanding of a null product (1 or
True), as compared to a null sum (0 or False):
the list of nodes for which
*any path* from source to x must touch, i.e., the list of dominators
I'm not sure I agree this is the common definition of dominators
Is one undefeated if one has never fought?
I should only ask for the dominators of nodes which I know are
reachable from the source node, right?
Yes.
Denis Bueno wrote:
On Thu, Apr 17, 2008 at 5:52 PM, Dan Weston [EMAIL
Sorry to be picky but there is no violation of the FD here. Note that
the class D has only a single ground instance and to violate an FD you
need at least two.
perhaps you are thinking of functional dependencies as
being defined extensionally, over the extent of the type
relations specified
jhc packs data into pointers when possible. so for instance
data Foo = Foo !Word16 !Word32
gets encoded as
---
| 16 bits | 32 bits | ... | 10|
---
This particularly helps strings, where the character can often be
encoded in
Ariel,
--- Ariel J. Birnbaum [EMAIL PROTECTED] wrote:
Common Misunderstandings - HaskellWiki
http://www.haskell.org/haskellwiki/Common_Misunderstandings
I didn't find this one... maybe it should be in a
more prominent place?
Things to avoid - HaskellWiki
Perhaps this is not the best mailing list for this
issue, but since this problem involves a library for
Haskell and is not a bug of GHC proper, I thought this
would be a better place than the Glasgow-haskell-bugs
mailing list
I tried installing wxHaskell 0.10.3 with GHCi 6.8.2
already
I just solved the problem by myself: It was a problem
with paths including spaces.
Originally, I had installed wxhaskell-register.bat in
the following directory:
C:\Documents and Settings\Benjamin\My
Documents\Haskell\Libraries\wxHaskell\wxhaskell-0.10.3\bin
However, the directory Documents
Dan Weston wrote:
Here, any path means all paths, a logical conjunction:
and [True, True] = True
and [True ] = True
and [ ] = True
Hate to nitpick, but what appears to be some kind of a
limit in the opposite direction is a curious way of arguing
that: and [] = True.
Dan Weston wrote:
Here, any path means all paths, a logical conjunction:
and [True, True] = True
and [True ] = True
and [ ] = True
Kim-Ee Yeoh wrote:
Hate to nitpick, but what appears to be some kind of a
limit in the opposite direction is a curious way of arguing
that:
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