Wolfgang Jeltsch-2 wrote:
No, I think, it’s the Prelude’s fault to define (==) as “floating point
equality”.
My bad, I meant IEEE (==) when I said it was our fault. I concur that the
Prelude is at fault for using the (==) symbol for FP equality. Even if you
don't
demand from (==) to be an
Smaller example of this behavior:
array ((0,0),(1,1)) [((1,1),6)] ! (0,3)
6
--
Eric Mertens
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ajb-2 wrote:
Define:
f = g = \x - f x = g
So you're either not taking (=) as primitive or you're stating the
additional
property that there exists (=) such that f = g === (= g) . f
(from which you can easily show that (f . g) = h === (f = h) . g ).
A presentation of the monad laws
G'day all.
Quoting askyle [EMAIL PROTECTED]:
So you're either not taking (=) as primitive or you're stating the
additional
property that there exists (=) such that f = g === (= g) . f
(from which you can easily show that (f . g) = h === (f = h) . g ).
If you wanted to prove that bind is
Here's the bug:
{-# INLINE safeIndex #-}
safeIndex :: Ix i = (i, i) - Int - i - Int
safeIndex (l,u) n i = let i' = unsafeIndex (l,u) i
in if (0 = i') (i' n)
then i'
else error Error in array index
unsafeIndex here is just
Hi
On 14 Mar 2008, at 03:48, Roman Leshchinskiy wrote:
Adrian Hey wrote:
I would ask for any correct Eq instance something like the law:
(x==y) = True implies x=y (and vice-versa)
which implies f x = f y for all definable f
which implies (f x == f y) = True (for expression types which are
Hello,
I've installed the HFuse package from hackage and am playing with the
HelloFS example in the System/Posix/HFuse directory.
The problem that I encounter is that listing the directory doesn't work:
% ghc --make HelloFS.hs
[1 of 1] Compiling Main ( HelloFS.hs, HelloFS.o )
Dan Weston wrote:
6.3.2 (The Ord Class):
The Ord class is used for totally ordered datatypes.
This *requires* that it be absolutely impossible in valid code to
distinguish equivalent (in the EQ sense, not the == sense) things via
the functions of Ord. The intended interpretation of these
Hello Sterling,
Friday, March 14, 2008, 7:06:24 AM, you wrote:
yes, it's another question. my own program also writes to logfile and
it got lock-free only when i've switched to using my own IO routines
This answer may be way off base, but if differences appear between
ghci and compiled
Hello, I have a problem with building multithreaded UDP server. If
main thread is waiting for new request in recvFrom all other threads
are blocked too. I've checked every variant with
forkIO,forkOS,-threaded etc, nothing's helped. After reading GHC docs
I've understood this is happened becouse
I am trying to figure out how to pass array of String (char **) from C
to Haskell? I have read the FFI examples, but most of them are centered
on calling C from Haskell. I have read in the mailing list, it is rare
to call Haskell from C, but my requirement is such that I am going to
write Haskell
Am Donnerstag, 13. März 2008 21:10 schrieben Sie:
Not to be picky, but where did you hear that (==) established an
equivalence relation?
I think that’s the way it should be according to most Haskeller’s opinion. It
might be true that the Haskell 98 report doesn’t say so but I think that many
Conor McBride wrote:
Hi
On 14 Mar 2008, at 03:48, Roman Leshchinskiy wrote:
Adrian Hey wrote:
I would ask for any correct Eq instance something like the law:
(x==y) = True implies x=y (and vice-versa)
which implies f x = f y for all definable f
which implies (f x == f y) = True (for
On Fri, Mar 14, 2008 at 09:54:11PM +0800, Verma Anurag-VNF673 wrote:
I am trying to figure out how to pass array of String (char **) from C
to Haskell? I have read the FFI examples, but most of them are centered
on calling C from Haskell. I have read in the mailing list, it is rare
to call
Rebuilding of the network package with changed safety helped but I
don't think this is the solution. BTW accept is declared as safe. What
is the reason of declaring recvFrom as unsafe? I think this breaks
highly required feature. Apparently it's impossible to make concurrent
server for non
On Fri, Mar 14, 2008 at 7:43 AM, Vitaliy Akimov
[EMAIL PROTECTED] wrote:
Rebuilding of the network package with changed safety helped but I
don't think this is the solution. BTW accept is declared as safe. What
is the reason of declaring recvFrom as unsafe? I think this breaks
highly
I assume that you're binding the libc function directly here:
I'm using Network.Socket. Sory if it's not clear from my previous posts.
In that case, you need to have the RTS manage sleeping your thread for
you. You should make the socket non-blocking and handle the EAGAIN and
EWOULDBLOCK
Am Samstag, 2. Februar 2008 14:54 schrieben Sie:
On Feb 1, 2008 10:32 PM, Wolfgang Jeltsch wrote:
Am Freitag, 1. Februar 2008 13:00 schrieb Alfonso Acosta:
[…]
To make it friendlier for the end user I thought about defining
aliases for lets say the first 1 numbers using Template
On Fri, Mar 14, 2008 at 5:30 PM, Wolfgang Jeltsch
[EMAIL PROTECTED] wrote:
I have a feedback from my Grapefruit co-developer about those aliases in the
type-level package. He told me that on his machine, building this package
took about 15 minutes, obviously because the machine ran out of
On Mar 12, 2008, at 4:07 PM, Andrew Coppin wrote:
I'm trying to read the file from Notepad.exe while my Haskell
program is still running - which takes about an hour.
I'm not a Windows user, but... Is it possible that Notepad tries to
write-lock by default (since it's an editor), and fails?
On Fri, Mar 14, 2008 at 8:51 AM, Vitaliy Akimov
[EMAIL PROTECTED] wrote:
I assume that you're binding the libc function directly here:
I'm using Network.Socket. Sory if it's not clear from my previous posts.
Then everything should Just Work(tm). You might need to paste in code
in order to
Roman Leshchinskiy wrote:
Should the report say something like a
valid Eq instance must ensure that x == y implies f x == f y for all f?
Probably not, since this requires structural equality which is not what
you want for ADTs. Should it be for all f which are not part of the
implementation of
On Fri, Mar 14, 2008 at 10:13 AM, Adam Langley [EMAIL PROTECTED] wrote:
See [1] for an example which works for me.
(If you're on Windows, you probably need to wrap main in withSocketsDo)
AGL
--
Adam Langley [EMAIL PROTECTED] http://www.imperialviolet.org
On Thu, Mar 13, 2008 at 4:50 PM, Krzysztof Kościuszkiewicz
[EMAIL PROTECTED] wrote:
Retainers are thunks or objects on stack that keep references to
live objects. All retainers of an object are called the object's
retainer set. Now when one makes a profiling run, say with ./jobname
+RTS
John Melesky wrote:
On Mar 12, 2008, at 4:07 PM, Andrew Coppin wrote:
I'm trying to read the file from Notepad.exe while my Haskell program
is still running - which takes about an hour.
I'm not a Windows user, but... Is it possible that Notepad tries to
write-lock by default (since it's an
Haskell has an expressive and powerful type system - which I love. It
also has a seemingly endless list of weird and obscure type system
extensions. And there are various things you can do in Haskell which
*require* some pretty serious type system hackery.
And yet, none of this happens in any
Hello,
It seems this bug has already been submitted:
http://hackage.haskell.org/trac/ghc/ticket/2120
Thanks for the help.
__
Donnie Jones
On 3/14/08, Cale Gibbard [EMAIL PROTECTED] wrote:
Here's the bug:
{-# INLINE safeIndex #-}
safeIndex :: Ix i = (i, i) - Int - i - Int
safeIndex (l,u) n
Just a short one... gtk2hs won't build on my [Linux] laptop. What's the
best channel for seeking help with this?
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Andrew Coppin wrote:
| Just a short one... gtk2hs won't build on my [Linux] laptop. What's the
| best channel for seeking help with this?
The #haskell (on freenode) isn't bad. You'll probably get help pretty
quick here, it's known to be very user
On Fri, Mar 14, 2008 at 2:50 PM, Andrew Coppin
[EMAIL PROTECTED] wrote:
Haskell has an expressive and powerful type system - which I love. It
also has a seemingly endless list of weird and obscure type system
extensions. And there are various things you can do in Haskell which
*require*
Am Freitag, 14. März 2008 17:46 schrieben Sie:
[…]
I think that removing aliases completely is not a good idea. How about
generating much lower aliases for decimals (lets say until 1000),
I don’t think, this is a good idea. Like nobody will need an alias for 8247,
nobody will need an alias
Don Stewart wrote:
andrewcoppin:
Just a short one... gtk2hs won't build on my [Linux] laptop. What's the
best channel for seeking help with this?
Discuss it on the gtk2hs list, with a full error log.
Thanks. I'll go look at that.
(Who knows, maybe somebody already solved this
Thanks. I was encouraged by this response I got. I'm ready to go.
Since I'm trapped in the space-time continuum like most people, I can't
do it all at once. I would like to. Anything that supports haskell is
okay by me. My first area of interest is HAppS. I wrote some e-mail to
them yesterday, but
On Fri, Mar 14, 2008 at 11:50 AM, Andrew Coppin
[EMAIL PROTECTED] wrote:
Haskell has an expressive and powerful type system - which I love. It
also has a seemingly endless list of weird and obscure type system
extensions...And yet, none of this happens in any other programming language
I've
dpiponi:
On Fri, Mar 14, 2008 at 11:50 AM, Andrew Coppin
[EMAIL PROTECTED] wrote:
Haskell has an expressive and powerful type system - which I love. It
also has a seemingly endless list of weird and obscure type system
extensions...And yet, none of this happens in any other programming
On 2008-03-14, Conor McBride [EMAIL PROTECTED] wrote:
Hi
On 13 Mar 2008, at 23:33, Aaron Denney wrote:
On 2008-03-13, Conor McBride [EMAIL PROTECTED] wrote:
For a suitable notion of = on quotients, and with a
suitable abstraction barrier at least morally in place,
is that really too much
Andrew Coppin wrote:
Haskell has an expressive and powerful type system - which I love. It
also has a seemingly endless list of weird and obscure type system
extensions. And there are various things you can do in Haskell which
*require* some pretty serious type system hackery.
And yet, none
Am Freitag, 14. März 2008 19:50 schrieb Andrew Coppin:
[…]
Is it because Haskell is used by more PhDs? Is it because Haskell
actually allows you to implement constructs that are impossible in other
languages? Is it because Haskell really provides greater type safety? Is
it something else?
On 2008-03-14, Robert Dockins [EMAIL PROTECTED] wrote:
Blah, blah, blah, its all in the documentation. The point is that making
loose assumptions about the meaning of the operations provided by Eq and Ord
complicates things in ways that can't be made to go away.
Thanks. All of these seem
Don Stewart wrote:
As Manuel says, in C++ type level programming was an accident, in
Haskell, it was by design.
Was it, really? I was laways under teh impression that Oleg-style type
system tricks were not in the least anticipated back when Haskell acquired
type classes...
Cheers
Ben
On 2008-03-10, Dan Weston [EMAIL PROTECTED] wrote:
However, the report text is normative:
6.3.2 (The Ord Class):
The Ord class is used for totally ordered datatypes.
This *requires* that it be absolutely impossible in valid code to
distinguish equivalent (in the EQ sense, not the ==
No, Haskell wasn't designed with type level programming in mind. In fact it
took a few years before any serious type level programming was done. And lo
and behold, the type level has an untyped logic language.
-- Lennart
On Fri, Mar 14, 2008 at 9:41 PM, Ben Franksen [EMAIL PROTECTED]
wrote:
Hi Andrew,
Andrew Coppin wrote:
Haskell has an expressive and powerful type system - which I love. It
also has a seemingly endless list of weird and obscure type system
extensions. And there are various things you can do in Haskell which
*require* some pretty serious type system hackery.
Yeah, I should clarify, this quote came up in relation to ATs, which
are designed speifically to make type programming easier (unlike MPTCs
and FDs, where it was an Olegian accident)
lennart:
No, Haskell wasn't designed with type level programming in mind.
In fact it took a few years
Note that even if you wanted Eq to mean observational equality, you
still can't perform that kind of reordering or 'sort' optimizations
without running into trouble. for a not contrived at all example:
data Id = Id { idIdent :: Int, idFreeVarCache :: [Id] }
instance Eq Id where
x == y =
Is there a known deconstruction of the list/backtracking applicative functor
(AF)? If I decompose the list type into pieces (Maybe, product,
composition), I think I can see where the ZipList AF comes from, but not the
list/backtracking AF. Is there some construction simpler than lists
Excerpts from Georg Neis's message of Fri Mar 14 06:38:02 -0500 2008:
Hello,
I've installed the HFuse package from hackage and am playing with the
HelloFS example in the System/Posix/HFuse directory.
As far as I know, the package uploaded onto hackage is merely a
cabal-ised version of the
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