I'm relatively new to Haskell, so maybe this answer is a bit off, in
that I'm sure there are times when some sort of auto-existential
creation may have a point, but generally I've found that when I want
it I've been thinking about the problem wrong.
The bigger issue is that as soon as you
Rene de Visser wrote:
I think a step towards support medium size documents in HXT would be to
store the tags and content more efficiently.
If I undertand the coding correctly every tag is stored as a seperate
Haskell string. As each byte of a string under GHC takes 12 bytes this alone
[only replying to haskell-cafe]
On 10/20/07, Rodrigo Geraldo [EMAIL PROTECTED] wrote:
Hi!
Suppose that the GHC's flag -fallow-incoherent-instances is enabled. In this
situation, when a instance will be rejected?
And if the flag -fallow-overlapping-instances is enabled. When a instance
will
Am Mittwoch, 24. Oktober 2007 10:35 schrieb Bas van Dijk:
Suppose you have:
{-# OPTIONS_GHC -fglasgow-exts -fallow-overlapping-instances #-}
classC a b where foo :: a - b - (a, b)
instance C Int a where foo n x = (n+1, x) -- (A)
instance C a Bool where foo x
TJ wrote:
data Showable = forall a. Show a = Showable a
stuff = [Showable 42, Showable hello, Showable 'w']
Which is exactly the kind of 2nd-rate treatment I dislike.
I am saying that Haskell's type system forces me to write boilerplate.
Nice :) I mean, the already powerful
On 10/24/07, Daniel Fischer [EMAIL PROTECTED] wrote:
This seems to be a typo.
g = f ([1,2,3] :: [Int]) is accepted.
Oops, a typo it is!
Bas.
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Uwe Schmidt wrote:
The hashtable approach would of course reduce memory usage,
Note that hashtables are evil :) I'm all for tries instead.
but this
would require a global change of the processing model: A document then
does not longer consist of a single tree, it alway consists of a pair of
On Wed, Oct 24, 2007 at 11:00:14AM +0800, TJ wrote:
Tristan Allwood:
Very cool. I don't understand some (a lot of) parts though:
instance Show a = Reify (ShowConstraint a) where reify = ShowC
ShowC has type (Show a) = ShowConstraint a, whereas reify is
supposed to have type
Dear Haskellers,
I am happy to announce a new version of GSLHaskell, a basic library for matrix
computations and other numeric algorithms based on LAPACK, BLAS and
GSL. The goal is that simple problems involving singular values, linear
systems, etc, can be easily solved using Haskell. The
apfelmus wrote:
Ah! I got struck by a trick: it's possible to store every tag name in
full only once but still present a simple tree with full tag names to
the user. You simply share all the tag names. For instance, in
let x = mytagname in Tree (Tag x) [Tree (Tag x) [Text foobar]]
the
Anyone who is serious about doing web development in Haskell is
welcome to apply for the job outlined below. If we found a good
functional programmer, we can ignore the bits about Rails.
Web Developer
RedNucleus Ltd (rednucleus.co.uk) is seeking a highly motivated
programmer for a full or
Thanks for posting this, I finally understand existentials!
This bit was specially helpful:
So, how to compute a value b from an existential type ∃a.(a - a)? ...
Could you give a specific example of computing existential types?
I think this shows why digested tutorials, as opposed to
On 10/23/07, Thomas Hartman [EMAIL PROTECTED] wrote:
Actually I can't compile it, with or without -O2. loads fine into ghci,
but when I try to create an executable I get
ghc quicksort.hs -o quicksort
quicksort.o: In function `r1Nc_info': undefined reference to
On Tue, Oct 23, 2007 at 15:50:54 +0200, Yitzchak Gale wrote:
Magnus Therning wrote:
My collection of data encoding functions are now available
Nice!
Should this effort be coordinated with Unicode-related
encoding/decoding? See the Encoding class in Twan van Laarhoven's
CompactString library:
a note recently went out regarding the first beta release of freebsd7
note that ghc is still marked as broken in the 7-branch ports tree due
to issues regarding the move from gcc3x to gcc4x. if you rely on ghc,
you may want to hold off on an upgrade
pgpPRFO4Q1yxk.pgp
Description: PGP signature
On 10/23/07, Galchin Vasili [EMAIL PROTECTED] wrote:
Hello,
I am trying to use a Haskell shell (Hsh.hs). I am a little
frustrated. There are two modules that are imported:
import LibPosix
import LibSystem
I am running WinHugs (Windows) and hugs/ghci can't find LibSystem. I am
Yitzchak Gale [EMAIL PROTECTED] wrote:
Another question about HaXML and HXT -
what is the level of XML spec. compliance?
In HaXml, I certainly tried pretty hard to match the (draft) XML 1.0
spec, since the library was originally developed for a commercial
entity. But that was back in 1999,
apfelmus wrote:
-+- Since ∀ and ∃ are clearly different, why does Haskell have only one
of them and even uses ∀ to declare existential types? The answer is the
following relation:
∃a.(a - a) = ∀b. (∀a.(a - a) - b) - b
So, how to compute a value b from an existential type ∃a.(a - a)?
Thanks for the concise explanation. I do have one minor question though.
-+- A more useful example is
∃a. Show a = a i.e. ∃a.(a - String, a)
So, given a value (f,x) :: ∃a.(a - String, a), we can do
f x :: String
but that's pretty much all we can do. The type is isomorphic to
Hi,
Are there binary constants in Haskell, as
we have, for instance, 0o232 for octal and
0xD29A for hexadecimal?
Thanks,
Maurício
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briqueabraque:
Hi,
Are there binary constants in Haskell, as
we have, for instance, 0o232 for octal and
0xD29A for hexadecimal?
No, though it is an interesting idea.
-- Don
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On 10/24/07, Peter Hercek [EMAIL PROTECTED] wrote:
I do not see why forall can be lifted to the top of function arrows.
I probably do not understand the notation at all. They all seem to be
different to me.
Consider this simple function:
\b x y - if b then x else y
Let's say we
Hi
Are there binary constants in Haskell, as
we have, for instance, 0o232 for octal and
0xD29A for hexadecimal?
No, though it is an interesting idea.
You can get pretty close with existing Haskell though:
(bin 100010011)
where bin :: Integer - Integer, and is left as an exercise for
ndmitchell:
Hi
Are there binary constants in Haskell, as
we have, for instance, 0o232 for octal and
0xD29A for hexadecimal?
No, though it is an interesting idea.
You can get pretty close with existing Haskell though:
(bin 100010011)
where bin :: Integer - Integer, and is
Prelude read 0o232 :: Int
154
Prelude read 0xD29A :: Int
53914
Prelude
Maurício wrote:
Hi,
Are there binary constants in Haskell, as
we have, for instance, 0o232 for octal and
0xD29A for hexadecimal?
Thanks,
Maurício
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brad clawsie [EMAIL PROTECTED] writes:
a note recently went out regarding the first beta release of freebsd7
note that ghc is still marked as broken in the 7-branch ports tree due
to issues regarding the move from gcc3x to gcc4x. if you rely on ghc,
you may want to hold off on an upgrade
Is
On Wed, Oct 24, 2007 at 06:14:49PM -0400, Xiao-Yong Jin wrote:
Is there any hope for it to be fixed before the freeze of
ports tree?
i believe that is the purpose of the extended beta/rc period, to allow
ports maintainers a chance to get things fixed before the main release
as it stands a fix
If someone organized something like that, (or even a more extended
version like the ongoing attempts a while back to optimize for the
language shootout) I'd be totally in. Seems like a great way for
newer foax to take a crack at something useful and interact to get a
better handle on the
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