Hello Johannes,
I think you are looking for HaskellDB, you can find it on hackage. I've
been working with it myself and can absolutely recommend it.
It is actively maintained by Justin Bailey.
It's a EDSL for relational algebra which gets translated into SQL. It
can use HDBC for instance as
I think you are looking for HaskellDB,
thanks, I'll look into it.
As with LINQ you need to put an initial effort into describing the
tables [...]
according to the documentation, that's what dbdirect is for?
I see the source, but not how to build it.
J.
can use HDBC for instance as its *driver* to databases supported by HDBC.
ok, so I guess I need haskelldb-hdbc-postgresql
but hdbc-postgresql has build failures
http://hackage.haskell.org/package/HDBC-postgresql
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Johannes Waldmann waldm...@imn.htwk-leipzig.de writes:
ok, so I guess I need haskelldb-hdbc-postgresql
but hdbc-postgresql has build failures
http://hackage.haskell.org/package/HDBC-postgresql
Looks like HDBC-postgresql's Setup.hs needs to be updated to use newer
versions of Cabal properly;
if you're using the latest release of the Haskell Platform [...]
but this would not work with ghc-6.12 ...
Anyway the trick is to remove AnyVersion from Setup.hs (thanks, Michael!)
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Victor Nazarov wrote:
Speaking about packages. What is current community status of monad
transformers packages. I'm using MonadIO class and there are mtl,
monads-fd, monads-tf packages that provide it. I personally prefer
type families to functional dependencies. Should I use monads-tf, or
On Thu, Feb 04, 2010 at 09:26:43AM +0100, Günther Schmidt wrote:
I think you are looking for HaskellDB, you can find it on hackage.
I've been working with it myself and can absolutely recommend it.
It is actively maintained by Justin Bailey.
It's been some time since I last tried HaskellDB
Edward Kmett wrote:
Functional references let you both read and write 'attributes' in a
structure. These can be chained to access members of members.
You can also use them to build bidirectional views on fields (and
compose those again as well).
Martijn.
Hi,
from all this I'm not so sure that these two techniques do not overlap.
I mean HList tries to provide a technique for extensible Records, or
composable data structures.
So far it is possible in Haskell to extend / compose Data Structures but
not at run-time and also rather clumsily.
What is currently the recommended
higher level data base interface for Haskell?
I want to construct queries in a programmatic/algebraic way,
Would takusen help? Where's its home page?
this does not work: http://darcs.haskell.org/takusen/
Takusen still requires you to supply queries as
Hi,
I'm using deeply nested types in my app and exceed some stack-size in ghci.
I can't remember the runtime option I have to pass to ghci anymore, it's
been about a year since I last pursued this approach.
Is it also possible to set this stack-size via pragma in the source code?
Günther
Hi,
Günther Schmidt schreef:
Hi,
I'm using deeply nested types in my app and exceed some stack-size in ghci.
I can't remember the runtime option I have to pass to ghci anymore, it's
been about a year since I last pursued this approach.
ghci +RTS --help suggests -Ksize Sets the maximum
Hello Ron,
thank you, but it was not the run-time stack size I meant. It was the
stack size for nested types which defaults to 20 or so IIRC. My nested
types currently go to about 23 deep.
Günther
Am 04.02.10 14:46, schrieb Ron de Bruijn:
Hi,
Günther Schmidt schreef:
Hi,
I'm using
2010/2/4 Günther Schmidt gue.schm...@web.de:
Hello Ron,
thank you, but it was not the run-time stack size I meant. It was the stack
size for nested types which defaults to 20 or so IIRC. My nested types
currently go to about 23 deep.
-fcontext-stack=100
Hello all,
few days ago I made some experiments with Haskell type classes. I wrote
a small Haskell program for searching in sorted lists, defining my own
type classes for equality (MyEq) and order (MyOrd) so that they only
have one member function:
Hello Serguey,
great, that's the one!
Can I set this in the source code itself too?
Günther
Am 04.02.10 15:26, schrieb Serguey Zefirov:
2010/2/4 Günther Schmidtgue.schm...@web.de:
Hello Ron,
thank you, but it was not the run-time stack size I meant. It was the stack
size for nested
2010/2/4 Günther Schmidt gue.schm...@web.de:
Hello Serguey,
great, that's the one!
Can I set this in the source code itself too?
No, as far as I know.
Last time I tried it on 6.10.1, so it's pretty far from now. ;)
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Hello Günther,
Thursday, February 4, 2010, 6:49:05 PM, you wrote:
Can I set this in the source code itself too?
http://www.haskell.org/ghc/docs/latest/html/users_guide/flag-reference.html
says that this option is dynamic so afaik it should work
--
Best regards,
Bulat
Hi everyone,
This is not an attempt to start a flame war. I'm just trying to get a good
feel for the advantages and disadvantages of the newer safe lazy io lib
available on Hackage vs using Iteratee.
It does appear to me that using something like Itereatee gives a bit of room
to really tweak
Hello haskell-cafe,
I currently have a problem with running par/pseq in the ST monad. The function
testST is the minimal counterexample that works -- or, to be more clear, does
not work as expected for me. As a remark, the tasks/function calls in my real
application are much more computational
Can't find a Stack datatype on Hoogle? Where should I look?
Michael
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On Feb 4, 2010, at 6:07 PM, michael rice wrote:
Can't find a Stack datatype on Hoogle? Where should I look?
Could not find one on Hackage either. Probably because its so easy to
handcraft your own:
newtype Stack a = Stack [a]
emptyStack = Stack []
isEmptyStack (Stack xs) =
anyone know what's happening here?
I get this when executing a query via haskelldb-hdbc-postgresql-0.12
(The date is actually in the DB, so it's not a connection problem.)
Convertible: error converting source data SqlString 2008-10-29 00:00:00 of
type SqlValue to type
I was looking here: http://www.haskell.org/haskellwiki/Abstract_data_type
I haven't done much with modules so I'm guessing what you've provided is the
guts of StackImpl, to hide the implementation?
Thanks,
Michael
--- On Thu, 2/4/10, Sebastian Fischer s...@informatik.uni-kiel.de wrote:
From:
On Thu, 4 Feb 2010 09:07:28 -0800 (PST), you wrote:
Can't find a Stack datatype on Hoogle? Where should I look?
Michael
From Algorithms: a functional programming approach
Second edition
Fethi Rabhi
Guy Lapalme
data Stack a= EmptyStk
Johannes == Johannes Waldmann waldm...@imn.htwk-leipzig.de writes:
Johannes anyone know what's happening here? I get this when
Johannes executing a query via haskelldb-hdbc-postgresql-0.12 (The
Johannes date is actually in the DB, so it's not a connection
Johannes problem.)
On Thu, 4 Feb 2010 09:07:28 -0800 (PST), you wrote:
Can't find a Stack datatype on Hoogle? Where should I look?
Michael
From Algorithms: a functional programming approach
Second edition
Fethi Rabhi
Guy Lapalme
To be more complete.
module Stack(Stack,push,pop,top,emptyStack,stackEmpty)
Am Donnerstag 04 Februar 2010 16:32:24 schrieb Enrique Martín:
Hello all,
few days ago I made some experiments with Haskell type classes. I wrote
a small Haskell program for searching in sorted lists, defining my own
type classes for equality (MyEq) and order (MyOrd) so that they only
have
try:
type DictMyEq a = a - a - Bool
-- From the definition of type class MyOrd
type DictOrd a = (DictMyEq a, a - a - Bool)
data Nat = Z | S Nat
-- From the instance MyEq Nat
eqNat :: Nat - Nat - Bool
eqNat Z Z = True
eqNat Z (S x) = False
eqNat (S x) Z = False
eqNat (S x) (S y)
Hi all,
I've just uploaded the first release of Progression to Hackage.
Progression is a small library that pulls together several other
libraries and utilities (particularly Criterion) to support the
optimisation of Haskell programs.
To use it, you wrap up your benchmarks in a program
Am Donnerstag 04 Februar 2010 17:50:57 schrieb Michael Lesniak:
Hello haskell-cafe,
I currently have a problem with running par/pseq in the ST monad. The
function testST is the minimal counterexample that works -- or, to be
more clear, does not work as expected for me. As a remark, the
On Thu, Feb 4, 2010 at 7:38 PM, Colin Paul Adams
co...@colina.demon.co.ukwrote:
Johannes == Johannes Waldmann waldm...@imn.htwk-leipzig.de
writes:
Johannes anyone know what's happening here? I get this when
Johannes executing a query via haskelldb-hdbc-postgresql-0.12 (The
Hi all,
I've been using the sendfile package off Hackage, but it seems to be
leaking file descriptors when using the Linux-native build.
What's happening in my specific case is the following:
1) client requests a range of a file
2) server starts sending the range
3) client
The problem is that the GUI code has become very ugly and I'm
tempted to rewrite it totally. I've been looking forward to the
FRP stuff, but I've never seen a single definition of the term.
Conal Eliot's denotational programming is too general to be
definition. I want to try Grapefruit, but
Excerpts from Magnus Therning's message of Wed Feb 03 21:51:34 +0200 2010:
Thanks. That pointed me in the right direction. I've posted the
attached patch as a suggested fix to the developer. Hopefully
there'll be a compilable version on Hackage soon.
There is now 0.1.5 on Hackage with GHC
Both have advantages and disadvantages. The primary advantage of lazy
IO over iteratees is that it's much, *much* easier to understand --
existing experience with monads can be used immediately. The downsides
of lazy IO, of course, are well documented[1][2][3].
Some are fixed by the safe/strict
Thanks for the detailed response below...
I must be able to understand how the resources will be used in my system for
mission-critical, long-running applications.
Dave
On Thu, Feb 4, 2010 at 12:51 PM, John Millikin jmilli...@gmail.com wrote:
Both have advantages and disadvantages. The
Hello John,
Thursday, February 4, 2010, 11:51:59 PM, you wrote:
tl;dr: Lots of smart people, with a history of being right about this
sort of thing, say iteratees are better. Evidence suggests
iteratee-based IO is faster and more predictable than lazy IO.
Iteratees are really hard to
On Wed, Feb 3, 2010 at 8:14 PM, Henk-Jan van Tuyl hjgt...@chello.nl wrote:
On Wed, 03 Feb 2010 23:34:34 +0100, Neil Mitchell ndmitch...@gmail.com
wrote:
Hi Gwern,
Please update: haskell-src-exts - haskell-src **Unknown**
This project was an unqualified success. haskell-src-exts is now one
data Stack a = EmptyStk | Stk a (Stack a)
I find it amusing that the book defined a type that is exactly isomorphic to
the standard list (EmptyStk === [] and Stk === (:)). I guess it's just for
clarity?
On Thu, Feb 4, 2010 at 12:29 PM, Casey Hawthorne cas...@istar.ca wrote:
On Thu, 4 Feb
On Thu, Feb 4, 2010 at 1:26 PM, Bulat Ziganshin
bulat.zigans...@gmail.comwrote:
Hello John,
Thursday, February 4, 2010, 11:51:59 PM, you wrote:
tl;dr: Lots of smart people, with a history of being right about this
sort of thing, say iteratees are better. Evidence suggests
iteratee-based
Am Donnerstag 04 Februar 2010 23:18:34 schrieb Daniel Peebles:
data Stack a = EmptyStk | Stk a (Stack a)
I find it amusing that the book defined a type that is exactly
isomorphic to the standard list (EmptyStk === [] and Stk === (:)). I
guess it's just for clarity?
Also type safety, I
On Feb 4, 2010, at 6:27 PM, michael rice wrote:
I haven't done much with modules so I'm guessing what you've
provided is the guts of StackImpl, to hide the implementation?
Right. In order to make the Stack type abstract, you can hide the
Stack data (that is, newtype) constructor and only
On 31 Jan 2010, Malcolm Wallace pointed out:
Google has announced that the Summer of Code programme will be running
again this year. If haskell.org people would like to take part again
this year, then we need volunteers:
The Darcs Team would certainly be delighted to participate in GSoC
Hello!
[snip]
We're particularly interested in three things:
(i) making Darcs faster
(ii) building nice GUI tools and
(iii) working seamlessly with SVN/Git repositories
[snip]
Both of these roles are called mentor in the Google system. Putting
together a good team of mentors before
Hello,
From: David Leimbach leim...@gmail.com
Hi everyone,
Yet at the same time, I'm quite enamored with the beauty of interact and
functions of that sort. I realize mixing the effects of the lazy IO and
pure code may not be the clearest way to write code for everyone, but there
is
On Feb 5, 2010, at 6:38 AM, Casey Hawthorne wrote:
On Thu, 4 Feb 2010 09:07:28 -0800 (PST), you wrote:
Can't find a Stack datatype on Hoogle? Where should I look?
Michael
module Stack(Stack,push,pop,top,emptyStack,stackEmpty) where
...
Or just use a list.
A more Haskellish approach to
Do you have a test script to reproduce the behavior?
I am interested in this patch-tag uses sendfile (via happstack) to
serve static data, and I'd like to know if I'm affected by this.
2010/2/4 Bardur Arantsson s...@scientician.net:
Hi all,
I've been using the sendfile package off Hackage,
Well, that's not good.
I wonder how we are supposed to know that the client has disconnected... We
use withBinaryFile to open the file, so if an uncaught except is being
thrown then that should close the file handle..
If you look in Network.Socket.SendFile.Linux, you will see that when the C
Actually,
We should start by testing if native sendfile leaks file descriptors even
when the whole file is sent. We have a test suite, but I am not sure if it
tests for file handle leaking...
- jeremy
On Thu, Feb 4, 2010 at 7:58 PM, Jeremy Shaw jer...@n-heptane.com wrote:
Well, that's not
Johannes Data.Time.LocalTime.LocalTime.LocalTime: Cannot parse
Johannes using default format string %Y-%m-%dT%T%Q
this actually comes from the default format string
that is defined in old-locale:System.Locale?
iso8601DateFormat :: Maybe String - String
iso8601DateFormat mTimeFmt
On 05/02/10 07:04, Johannes Waldmann wrote:
Johannes Data.Time.LocalTime.LocalTime.LocalTime: Cannot parse
Johannes using default format string %Y-%m-%dT%T%Q
this actually comes from the default format string
that is defined in old-locale:System.Locale?
iso8601DateFormat
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