On Sun, Jun 28, 2009 at 10:05 PM, Tony Morris wrote:
> Is there a canonical function for traversing the spine of a list?
>
> I could use e.g. (seq . length) but this feels dirty, so I have foldl'
> (const . const $ ()) () which still doesn't feel right. What's the
> typical means of doing this?
Yo
Hi folks,
I'm having trouble reasoning about laziness and FFI resources. I've
written a little C wrapper function to augment Text.XML.LibXML; given
a Ptr Node, it will return the node's tag-name:
foreign import ccall unsafe _getName :: Ptr Node -> IO CString
Given LibXML's 'withNode' function,
2008/9/30 wman <[EMAIL PROTECTED]>:
> Thanks a lot, I've had a hunch it was possible to get rid of those those
> liftM's. I turned it into:
>
> (writeFile "output.csv") . printCSV . (map updateLine) . (either (error
> "Chyba pri cteni CSV.") id) =<< parseCSVFromFile "input.csv"
>
> and am sincerely
2008/9/30 wman <[EMAIL PROTECTED]>:
> I got asked how to do one particular thing in excel, which led to discssion
> with "our local MSOffice expert".
> During the discussion I stated that's it too much of a PITA and that I'd
> rather write a script.
> Long story short, I promised him a one-liner to
On Tue, Sep 30, 2008 at 9:18 AM, Manlio Perillo
<[EMAIL PROTECTED]> wrote:
> Graham Fawcett ha scritto:
>>
>> On Thu, Sep 25, 2008 at 5:09 PM, Manlio Perillo
>> <[EMAIL PROTECTED]> wrote:
>>>
>>> Graham Fawcett ha scritto:
>>>&g
On Tue, Sep 30, 2008 at 9:18 AM, Manlio Perillo
<[EMAIL PROTECTED]> wrote:
> Graham Fawcett ha scritto:
>>
>> On Thu, Sep 25, 2008 at 5:09 PM, Manlio Perillo
>> <[EMAIL PROTECTED]> wrote:
>>>
>>> Graham Fawcett ha scritto:
>>>&g
On Thu, Sep 25, 2008 at 5:09 PM, Manlio Perillo
<[EMAIL PROTECTED]> wrote:
> Graham Fawcett ha scritto:
>> If you're on Intel/Itanium, I believe there's a CMPXCHG instruction
>> that will do atomic compare-and-set on a memory address, and I'm not
>>
On Wed, Sep 24, 2008 at 5:17 PM, Manlio Perillo
<[EMAIL PROTECTED]> wrote:
> Hi.
>
> I need a simple, concurrent safe, database, written in Haskell.
> A database with the interface of Data.Map would be great, since what I need
> to to is atomically increment some integer values, and I would like to
On Mon, Sep 22, 2008 at 1:12 PM, Bulat Ziganshin
<[EMAIL PROTECTED]> wrote:
> Hello Simon,
>
> Monday, September 22, 2008, 9:03:52 PM, you wrote:
>
>> With bytestrings, unboxed arrays, light-weight threads and other
>> tricks, we can usually replace all those ugly low-level programs with
>> nice hi
On Wed, May 14, 2008 at 1:38 AM, Janis Voigtlaender
<[EMAIL PROTECTED]> wrote:
> Graham Fawcett wrote:
>>
>> Yes, but that's still a 'quick' short-circuiting. In your example, if
>> 'n' is Nothing, then the 'f >>= g >>= h
On Mon, May 12, 2008 at 6:09 PM, John Hamilton <[EMAIL PROTECTED]> wrote:
> I'm trying to understand how short circuiting works with the Maybe monad.
> Take the expression n >>= f >>= g >>= h, which can be written as
> (((n >>= f) >>= g) >>= h) because >>= is left associative. If n is
> Nothing
On Fri, May 2, 2008 at 12:16 AM, Donn Cave <[EMAIL PROTECTED]> wrote:
> Graham Fawcett wrote:
>
>
> > I would like to communicate with an external, line-oriented process,
> > which takes a sequence of one-line commands, each returning an
> > arbitrary number of lin
Hi folks,
I would like to communicate with an external, line-oriented process,
which takes a sequence of one-line commands, each returning an
arbitrary number of lines, and waits for another command after each
response. So, something like:
sendCmd :: (Handle, Handle) -> String -> IO [String]
...
On Thu, Apr 24, 2008 at 12:44 AM, Graham Fawcett
<[EMAIL PROTECTED]> wrote:
> I'm studying zippers (and by extension, the State monad), and have
> written a function for finding the first node-location in a 'zippered'
> tree that satisfies a predicate:
>
>
Hi folks,
I'm studying zippers (and by extension, the State monad), and have
written a function for finding the first node-location in a 'zippered'
tree that satisfies a predicate:
http://paste.lisp.org/display/59636
(The code uses Krasimir Angelov's Data.Tree.Zipper.) My code works,
but I suspe
On Wed, Apr 23, 2008 at 4:40 PM, Krasimir Angelov <[EMAIL PROTECTED]>
wrote:
> Hi Graham,
>
> There is one implementation here:
>
> http://code.haskell.org/yi/Data/Tree/
>
> I wrote it for Yi but it is quite general. It is a pity that we don't
> have it in the standard libraries. It is not complet
Hi folks,
Is there a common zipper implementation for the "Tree a" datatype, defined
in Data.Tree? The wiki gives examples for binary trees and B-trees, but not
for these.
Thanks,
Graham
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www
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
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.
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 lea
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?
>
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
way?
Graham
___
On Wed, Apr 16, 2008 at 5:30 PM, John Goerzen <[EMAIL PROTECTED]> wrote:
> On Wed April 16 2008 3:54:45 pm Galchin, Vasili wrote:
> > hi Antoine,
> >
> >I already found this link. Thanks in any case. I want to O_CREATE a
> > file, i.e. do a openFd creating a new file. O_CREATE should be the
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 module 'App' and submodules
'App.Front' and 'App.Back
On Jan 14, 2008 2:47 AM, Sterling Clover <[EMAIL PROTECTED]> wrote:
> HStringTemplate is a port of Terrence Parr's lovely StringTemplate
> (http://www.stringtemplate.org) engine to Haskell.
This is very cool.
Your docs describe a function, cacheSTGroup:
cacheSTGroup :: Int -> STGen a -> STGen a
On Jan 9, 2008 6:20 PM, Don Stewart <[EMAIL PROTECTED]> wrote:
> anton:
> > Oh dear - I'm going to have to rethink the paper I was working on,
> > provisionally titled "In defense of arbitrary untracked effects in high
> > assurance software." ;)
>
> That would be an awesome paper :)
Hear, hear!
On Nov 27, 2007 11:14 AM, Henning Thielemann
<[EMAIL PROTECTED]> wrote:
> I think this is true, but for me it means, that we do not need another
> advertisement at Haskell.org, but facts. I also expect that people
> visiting the site already know about static typing and have categorized
> themselve
On Nov 17, 2007 4:52 PM, Radosław Grzanka <[EMAIL PROTECTED]> wrote:
> > > Also:
> > > $ ./get http://digg.com/rss/indexvideos_animation.xml
>
> However this one still seems to hang and eventually ends with :
> get: recv: resource vanished (Connection reset by peer)
It's not a Haskell problem. It
otting.
I'd be interested, for one.
Cheers,
Graham
Graham Fawcett
Centre for Teaching and Learning
University of Windsor
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
On Nov 7, 2007 4:34 PM, Nicholas Messenger <[EMAIL PROTECTED]> wrote:
> If you're willing to have an extra Typeable constraint, this does what you
> want:
>
> > import Data.Typeable (Typeable, cast)
> > import Data.Maybe (fromMaybe)
> >
> > toString :: (Show a, Typeable a) => a -> String
> > toStr
On Nov 6, 2007 3:29 PM, Graham Fawcett <[EMAIL PROTECTED]> wrote:
> On Nov 6, 2007 2:21 PM, Jeff Polakow <[EMAIL PROTECTED]> wrote:
> > Have you tried using -fglasgow-exts? That should enable all ghc
> > extensions.
If anyone's interested, I had best resul
On Nov 6, 2007 2:21 PM, Jeff Polakow <[EMAIL PROTECTED]> wrote:
> Have you tried using -fglasgow-exts? That should enable all ghc
> extensions.
Ah thanks, that does it.
G
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mai
On Nov 6, 2007 12:03 PM, Thomas Schilling <[EMAIL PROTECTED]> wrote:
> On Tue, 2007-11-06 at 09:18 -0500, Graham Fawcett wrote:
> > Hi folks,
> > Is there a way to declare a 'toString' function, such that
> > toString x | = x
> > toString x | = show
On Nov 6, 2007 12:15 PM, David Benbennick <[EMAIL PROTECTED]> wrote:
> In ghc 6.8.1, the error messages are more helpful:
>
> foo.hs:5:0:
> Illegal instance declaration for `MyShow String'
> (All instance types must be of the form (T t1 ... tn)
> where T is not a synonym.
>
On Nov 6, 2007 10:30 AM, Bayley, Alistair
<[EMAIL PROTECTED]> wrote:
> > From: [EMAIL PROTECTED]
> > [mailto:[EMAIL PROTECTED] On Behalf Of Graham Fawcett
> > Is there a way to declare a 'toString' function, such that
> > toString x | = x
> > toStrin
Hi folks,
Is there a way to declare a 'toString' function, such that
toString x | = x
toString x | = show x
Perhaps, in the type system, there's a way to declare a ToString
class, and somehow "inherit" all instances of Show as ToString
instances?
Thanks,
Graham
___
On Nov 5, 2007 1:46 PM, Maurício <[EMAIL PROTECTED]> wrote:
> Hi,
>
> Is there a way to run 'ghc -e' taking input
> from standard input? I would like to use it
> in a pipe.
It seems to me that you can use getContents, et. al., as you would
from any other Haskell program:
$ echo hello there mauri
On 10/26/07, Brent Yorgey <[EMAIL PROTECTED]> wrote:
>In the end it looks to me like you're probably better off
> just implementing traverse directly as you have done, although perhaps
> someone will find a better way.
Beginner's luck. ;-) I see the unfold similarity, but yes, it doesn't
seem a go
On 10/25/07, Derek Elkins <[EMAIL PROTECTED]> wrote:
> On Thu, 2007-10-25 at 11:30 -0400, Graham Fawcett wrote:
> > I'm writing a Gnu DBM module as an exercise for learning Haskell and
> > its FFI. I'm wondering how I might write a function that returns the
> >
On 10/25/07, Brandon S. Allbery KF8NH <[EMAIL PROTECTED]> wrote:
> On Oct 25, 2007, at 14:21 , Ryan Ingram wrote:
> > Right, but if you do something like
> >
> > do
> > keys <- getKeysLazy db
> > [.. some computation A here that may or may not evaluate all the
> > keys ..]
> > addRow db newRo
On 10/25/07, Derek Elkins <[EMAIL PROTECTED]> wrote:
> On Thu, 2007-10-25 at 11:30 -0400, Graham Fawcett wrote:
> > I'm writing a Gnu DBM module as an exercise for learning Haskell and
> > its FFI. I'm wondering how I might write a function that returns the
> &g
Hi folks,
I'm writing a Gnu DBM module as an exercise for learning Haskell and
its FFI. I'm wondering how I might write a function that returns the
database keys as a lazy list. I've wrapped the two relevant foreign
functions:
firstKey :: Ptr Db -> IO (Maybe String)
nextKey :: Ptr Db ->
42 matches
Mail list logo
