I'm afraid I won't attend the event, but I have to say that you have one of
the very best Haskell logos I've ever seen :)
2013/6/4 lucas di cioccio
> Dear all,
>
> I'm happy to announce that the Haskell-Paris group will meet on June 25th
> in Paris. Please register (free) at
> http://www.meetup
h GHC (GHC depends
on binary).
In other words, depending on binary should be future-proof.
On another note, binary-0.7 is out, get it while it's hot! :)
Lennart
2013/2/26 Johan Tibell
> On Mon, Feb 25, 2013 at 4:51 PM, Alexander Solla wrote:
>
>> On Mon, Feb 25, 2013 at 11:59 AM
if this has been discussed
before, I searched the mailing list without finding anything.
Feels like Happstack has been reborn, thanks again!
Cheers,
Lennart
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
You seem to ignore garbage collection.
On Sat, Sep 24, 2011 at 6:40 AM, Arseniy Alekseyev <
arseniy.alekse...@gmail.com> wrote:
> > Apparently it doesn't, and it seems to be fixed now.
>
> Does anyone know what exactly the bug was? Because this seems like a
> serious bug to me. I've run into it m
I totally agree with you. Haskell is very broken when it comes to [x..y]
for floating point.
It's an attempt to make it more "friendly" for naive users, but there is no
way FP can be made friendly. Any such attempts will fail, so make it usable
for people who understand FP instead
If you do [0.1, 0.2 .. 0.3] it should leave out 0.3. This is floating point
numbers and if you don't understand them, then don't use them. The current
behaviour of .. for floating point is totally broken, IMO.
-- Lennart
On Fri, Sep 23, 2011 at 6:06 AM, Chris Smith wrote:
> On
he
> > idea very useful and tried to use it. Original library by Lennart
> > Kolmodin raises some questions. The lib's main data structures are:
> >
>
> Lennart Kolmodin has a branch of Binary with incremental get which
> supports lookAhead:
>
> https://gith
It probably is portable, but I'd think only GHC has all the necessary
extensions.
On Sun, Jan 23, 2011 at 12:27 PM, Maciej Piechotka wrote:
> It may be strange question but:
>
> - Is SHE portable (assuming that the compiler have the extensions)?
> - If yes why there is only information how to u
That looks like it looses the efficiency of the underlying representation.
On Sun, Jan 9, 2011 at 6:45 AM, Sebastian Fischer wrote:
> On Sun, Jan 9, 2011 at 6:53 AM, Lennart Augustsson > wrote:
>
>> It so happens that you can make a set data type that is a Monad, but it'
It so happens that you can make a set data type that is a Monad, but it's
not exactly the best possible sets.
module SetMonad where
newtype Set a = Set { unSet :: [a] }
singleton :: a -> Set a
singleton x = Set [x]
unions :: [Set a] -> Set a
unions ss = Set $ concatMap unSet ss
member :: (Eq a
First, what type would such a function have?
Certainly not [a]->[b], because that type say that it can take a list of any
type and turn it into a list of any other type, e.g.,
[Int]->[Bool].
On Thu, Dec 30, 2010 at 4:05 AM, william murphy wrote:
> Hi All,
>
> I've spent a lot of time trying to w
Recursion replaces loops. If it needs to be monadic or not depends on what
you want to do.
On Sun, Dec 19, 2010 at 10:53 AM, ender wrote:
> 2010/12/19 Henning Thielemann :
> >
> > On Sun, 19 Dec 2010, ender wrote:
> >
> >>> do
> >>> alloca $ \value -> do
> >>> poke value (50::Int)
> >>>
I bet they did try to contact the owner. But when the contact email no
longer works nobody will get the messages.
On Sat, Dec 18, 2010 at 3:35 PM, Ketil Malde wrote:
> Karel Gardas writes:
>
> >
> http://www.reddit.com/r/haskell/comments/encrv/whats_happened_to_haskellorg_did_someone_forget/c1
IO
On Thu, Dec 16, 2010 at 6:03 PM, John Smith wrote:
> On 15/12/2010 14:31, Lennart Augustsson wrote:
>
>> Yes, I think there should be a MonadFail distinct from MonadPlus.
>> Some types, like IO, are not in MonadPlus, but have a special
>> implementation of the fail
reasons (better error messages
was the excuse).
-- Lennart
On Wed, Dec 15, 2010 at 11:51 AM, John Smith wrote:
> On 15/12/2010 11:39, Lennart Augustsson wrote:
>
>> Any refutable pattern match in do would force MonadFail (or MonadPlus if
>> you prefer). So
>> 1. (MonadFa
quot;; Just x -> return x
4. (Monad m) => a -> b -> m a, \ a b -> return a
5. (Monad m) => (a, b) -> m a, \ (a, b) -> return a
As far as type inference and desugaring goes, it seems very little would
have to be changed in an implementation.
-- Lennart
2010/12/
had a compiler that was bootstrapped, but I had a simple
functional language that compiled itself and ran in 64K.
The smallest bootstrapped Haskell compiler is NHC which (I think) runs
in a few MB.
-- Lennart
On Thu, Nov 4, 2010 at 8:54 PM, Andrew Coppin
wrote:
> Where the heck did all this
KRC, Miranda, and LML all predate Haskell and have list comprehensions.
On Thu, Nov 4, 2010 at 3:16 PM, Jonathan Geddes
wrote:
> Regardless of which languages got which features for which other
> languages, Haskell is surely NOT a "scripting language inspired by
> python"...
>
> Also, it was my u
Jon, you beat me to it. I was going to mention Ponder.
But Ponder did have a builtin type, it had the function type built in. :)
-- Lennart
On Tue, Nov 2, 2010 at 9:47 PM, Jon Fairbairn
wrote:
> Andrew Coppin writes:
>
>> The other day, I accidentally came up with this:
>>
I don't understand. Why don't you use Haskell as the scripting language?
On Tue, Nov 2, 2010 at 7:04 AM, Permjacov Evgeniy wrote:
> Let us think, that we need some scripting language for our pure haskell
> project and configure-compile-run is not a way. In such a case a
> reasonably simple, yet
It's working just fine. I've never wanted a mail client library. :)
-- Lennart
2010/10/27 Günther Schmidt :
> Dear Malcolm,
>
> since there is no mail client library even after 10+ years I suggest to
> rethink the approach, because frankly, it'
I would not worry about doing that at runtime.
The only reliable way to make sure it happens at compile time that I
can think of would be some Template Haskell.
(Or some really deep magic with dictionaries.)
-- Lennart
On Mon, Oct 11, 2010 at 3:51 AM, Alexander Solla wrote:
> Hi everyb
b -> c -> (b1,c1,a1)) ->
(a -> b -> c -> d)
compose :: (c1 -> a1 -> d) -> (a -> b -> c -> (b1, c1, a1)) -> a -> b -> c -> d
compose a b c d e =
case b c d e of
(_, f, g) -> a f g
-- Lennart
2010/10/9 André Batista Martins :
That code is incorrect. You can't assume that the base for floating
point numbers is 2, that's something you have to check.
(POWER6 and z9 has hardware support for base 10 floating point.)
-- Lennart
On Fri, Oct 8, 2010 at 2:08 PM, Daniel Fischer wrote:
> The methods of the R
So it's a bug in the garbage collector. It's closing a handle that
clearly is still reachable, otherwise this would not have happened.
On Fri, Aug 13, 2010 at 10:53 AM, Simon Marlow wrote:
> On 12/08/2010 21:59, Yitzchak Gale wrote:
>>
>> Wei Hu wrote:
>>>
>>> nonTermination _ = blackhole where
The former.
On Tue, Aug 10, 2010 at 2:59 PM, Ivan Lazar Miljenovic
wrote:
> Lennart Augustsson writes:
>
>> Rather than high turnover it indicates (in my experience) that it's
>> difficult to fill positions in finance.
>> That's one reason they are advertised
Rather than high turnover it indicates (in my experience) that it's
difficult to fill positions in finance.
That's one reason they are advertised repeatedly.
On Tue, Aug 10, 2010 at 12:27 PM, Ivan Lazar Miljenovic
wrote:
> Malcolm Wallace writes:
>
It's disproportionate. 95% of the job off
But do you think there would be more Haskell jobs offered (in absolute
terms), if no investment firms offered jobs?
Is there some kind of quota of job offers that gets used up?
There seems to be more job applicants that job offers at the moment,
so I'm not sure what the problem is.
On Mon, Aug 9,
Out of 10 people trained only 2 should do programming anyway. :)
On Fri, Aug 6, 2010 at 4:58 AM, Tom Hawkins wrote:
> Hi Eil,
>> Have you had any trouble training people to use Haskell?
>
> Yes. I find that out of 10 people I train, only about 2 pick it up
> and run with it. I'm starting to bel
Yes, for instance to be able to use functions as number.
Or to be able to use constructive real numbers as numbers, since
equality is not computable.
-- Lennart
On Thu, Aug 5, 2010 at 4:17 AM, Ivan Lazar Miljenovic
wrote:
> On 5 August 2010 10:15, Lennart Augustsson wrote:
>> You
You're right. It's bad to have toRational in Real. It's also bad to
have Show and Eq as superclasses to Num.
On Wed, Aug 4, 2010 at 8:30 PM, Omari Norman wrote:
> Why is toRational a method of Real? I thought that real numbers need not
> be rational, such as the square root of two. Wouldn't it
ted constraints,
www.cs.kuleuven.be/~toms/Research/papers/constraint_families.pdf
On Tue, Jul 27, 2010 at 10:17 AM, wrote:
>
> Lennart Augustsson wrote:
>> Try to make Set an instance of Functor and you'll see why it isn't.
>> It's very annoying.
>
> And yet th
Try to make Set an instance of Functor and you'll see why it isn't.
It's very annoying.
On Mon, Jul 26, 2010 at 11:55 PM, Gregory Crosswhite
wrote:
> Is there a specific reason why Set doesn't have instances for Functor
> and Traversable? Or have they just not been written yet? :-)
>
> Cheers,
I would not use the continuation monad just for early exit. Sounds
like the error monad to me.
2010/6/10 Günther Schmidt :
> Hi everyone,
>
> I'm about to write a rather lengthy piece of IO code. Depending on the
> results of some of the IO actions I'd like the computation to stop right
> there a
f you just consider cut free proofs there's usually infinitely many.)
On Fri, May 28, 2010 at 8:14 AM, wren ng thornton wrote:
> Lennart Augustsson wrote:
>>
>> So what would you consider a proof that there are no total Haskell
>> functions of that type?
>> Or,
proof that there is no function of that type.
-- Lennart
On Thu, May 27, 2010 at 7:49 PM, wren ng thornton wrote:
> Dan Doel wrote:
>>
>> On Thursday 27 May 2010 3:27:58 am wren ng thornton wrote:
>>>
>>> By parametricty, presumably.
>>
>> Actually,
There are no interesting (i.e. total) functions of that type.
2010/5/25 Yitzchak Gale :
> Günther Schmidt wrote:
>> http://www.hpaste.org/fastcgi/hpaste.fcgi/view?id=25694
>> in which I attempt to develop a "currying combinator" library.
>> I'm stuck at some point and would appreciate any help.
>
That's totally false. You don't evaluate 'undefined' before calling 'id'.
(Or if you, it's because you've made a transformation that is valid
because 'id' is strict.)
On Mon, May 24, 2010 at 9:05 AM, Alexander Solla wrote:
> Yes, but only because it doesn't work at all. Consider that calling
>
Actually, I didn't notice the typo. It's still not a true statement.
(h . either (f, g)) undefined /= (either (h . f, h . g)) undefined
Also, it's not exactly the function either from the Prelude.
-- Lennart
2010/5/23 R J :
> Correction: the theorem is
> h . eith
There is no clean proof of that statement because it is false.
(Consider the argument 'undefined'.)
2010/5/23 R J :
> Given the following definition of "either", from the prelude:
> either :: (a -> c, b -> c) -> Either a b -> c
> either (f, g) (Left x) = f x
>
#x27; does not.
Ignore bottom at your own peril.
BTW, the id function works fine on bottom, both from a semantic and
implementation point of view.
-- Lennart
On Sun, May 23, 2010 at 11:23 AM, Alexander Solla wrote:
>
> On May 23, 2010, at 1:35 AM, Jon Fairbairn wrote:
>
>> It
ses the default
implementation for showList.
-- Lennart
On Mon, May 17, 2010 at 4:56 AM, Abby Henríquez Tejera
wrote:
> Hi.
>
> I'm a Haskell newbie and there's a bit of Haskell code that I don't
> understand how it works. In the prelude, defining the class Show, the
>
The cost factor of Integer vs Int is far, far smaller than the factor
between computable reals vs Double.
On Thu, Apr 1, 2010 at 6:33 PM, Jens Blanck wrote:
> Yes, the cost for computable reals will be an order of magnitude or possibly
> two for well-behaved computations. For not well-behaved pro
Of course Haskell' should have an empty case. As soon as empty data
declarations are allowed then empty case must be allowed just by using
common sense.
On Tue, Mar 30, 2010 at 11:03 PM, Ashley Yakeley wrote:
> wagne...@seas.upenn.edu wrote:
>>
>> I believe I was claiming that, in the absence of
What Don said.
2010/3/29 Don Stewart :
> gue.schmidt:
>> Hi all,
>>
>> I notice that posts from the Haskell elders are pretty rare now. Only
>> every now and then we hear from them.
>>
>> How come?
>
> Because there is too much noise on this list, Günther
>
> -- Don
> _
Does anything change if you swap the first two rhss?
On Sun, Mar 28, 2010 at 1:28 AM, Roman Leshchinskiy
wrote:
> On 28/03/2010, at 09:47, Lennart Augustsson wrote:
>
>> It's important to switch from mod to rem. This can be done by a
>> simple abstract interpretation.
It's important to switch from mod to rem. This can be done by a
simple abstract interpretation.
I'm nore sure if it's jhc or gcc that does this for jhc.
-- Lennart
On Sat, Mar 27, 2010 at 10:30 PM, Rafael Cunha de Almeida
wrote:
> John Meacham wrote:
>> Here are jh
Turn on OverloadedStrings and you can pattern match on any type you
like that is in the IsString class.
Which means that Data.Text can use string literals just like regular
strings (but you can't use Char literals in the match).
On Mon, Mar 22, 2010 at 1:15 PM, Ivan Miljenovic
wrote:
> On 23 Marc
If you use read (reads) and show for the actual conversion it will round trip.
It appears to be non-trivial since most languages and libraries get it wrong. :)
-- Lennart
On Tue, Feb 23, 2010 at 1:44 PM, Andy Gimblett wrote:
> Hi all,
>
> Short version: How can I pretty print and par
Supply a fix for the problem, and it will probably get included.
There has probably been little demand for this feature so far.
-- Lennart
On Sun, Feb 21, 2010 at 10:21 PM, Ben Millwood wrote:
> On Sun, Feb 21, 2010 at 7:10 PM, Max Bolingbroke
> wrote:
>>
>> You mi
y wish-list for haskell-src-exts, and I'm hoping
> the stuff Lennart will contribute will go a long way towards making it
> feasible. I believe I can safely say that no such tool exists (and if
> it does, why haven't you told me?? ;-)), but if you implement (parts
> of) one you
It does type inference, it's just not engineered to be part of a real compiler.
On Thu, Feb 11, 2010 at 6:41 PM, Stephen Tetley
wrote:
> http://web.cecs.pdx.edu/~mpj/thih/
>
> Looks like its a type _checker_ though...
>
>
> On 11 February 2010 17:39, Stephen Tetley wrote:
>> Hello Job
>>
>> For
To do anything interesting you also to process modules, something
which I hope to contribute soon to haskell-src-exts.
On Thu, Feb 11, 2010 at 6:35 PM, Job Vranish wrote:
> Anyone know of a type inference utility that can run right on haskell-src
> types? or one that could be easily adapted?
> I
ances in
Uniplate would just be plain idiotic.
Including the Uniplate instances with HSE would make some sense, but
would make HSE artificially depend on Uniplate for those who don't
want the instances.
So, what's left is to make orphan instances (that I own). It's not
ideal, but I
PL/I has keywords, they're just not reserved words.
With as many keywords as PL/I has, there something to say for not
making them reserved. :)
On Wed, Jan 13, 2010 at 11:50 AM, Brandon S. Allbery KF8NH
wrote:
> On Jan 13, 2010, at 05:45 , Ketil Malde wrote:
>>
>> "Brandon S. Allbery KF8NH" write
I've put some of Oleg's code on hackage, named polytypeable.
> import Data.PolyTypeable
> main = print [polyTypeOf Nothing, polyTypeOf Just]
This prints
[Maybe a1,a1 -> Maybe a1]
To get a list of the actual constructors you need to derive
Data.Data.Data and use that.
Did you consider using the traced package?
2009/12/24 Bas van Dijk :
> On Thu, Dec 24, 2009 at 1:00 AM, Andrey Sisoyev
> wrote:
>> Where do you make use of it? :)
>
> A few months ago I was working on 'levmar'[1] a Levenberg-Marquardt
> data fitting library in Haskell. If you want your data fitti
And if you use quotRem it's faster (unless you're running on some
exotic hardware like NS32K).
On Tue, Dec 8, 2009 at 10:19 PM, Richard O'Keefe wrote:
>
> On Dec 9, 2009, at 1:15 AM, Daniel Fischer wrote:
>
>> Am Dienstag 08 Dezember 2009 08:44:52 schrieb Ketil Malde:
>>>
>>> "Richard O'Keefe" w
Thank you Sir for giving me a good laugh!
On Thu, Dec 3, 2009 at 5:25 PM, John D. Earle wrote:
> Dear Emmanuel Chantréau,
>
> You may want to look into Objective CAML http://caml.inria.fr/ which is a
> French product as you can see from the Internet address. It is likely better
> suited to the ta
Try with -XExtendedDefaulingRules.
On Mon, Nov 16, 2009 at 6:33 AM, Mark Lentczner wrote:
> I'm looking for a good way to handle a library interface that accepts both
> strings and numbers in particular argument positions:
>
> Start with the following definitions. I've defined ResourceTree as a
Hugs is wrong, as you can easily see by evaluating
let x = 123.35503 * 10.0 in x == read (show x)
With ghc it comes out as True and with Hugs as False.
-- Lennart
On Sat, Nov 14, 2009 at 9:00 PM, Abby Henríquez Tejera
wrote:
> Hi.
>
> I've seen that in GHC sometimes there are
e second one.
Some people thought it was to error prone not to have any indication
when an existential type is introduced,
so instead we are now stuck with a somewhat confusing keyword.
-- Lennart
On Sat, Nov 14, 2009 at 4:55 PM, Mark Lentczner wrote:
> On Nov 12, 2009, at 2:59 PM, Sean Leather
Thanks Neil,
That was indeed my point. Since a compiler is a substantial program I
would have more confidence it a compiler that is self-hosting.
Surely you must have tried?
-- Lennart
On Fri, Nov 13, 2009 at 8:08 PM, Neil Mitchell wrote:
> Hi John,
>
>>> Do you use jhc when
If by minority platform you mean platforms that are resource starved,
like some embedded systems, then I would have to agree.
-- Lennart
On Wed, Nov 11, 2009 at 2:12 PM, Donn Cave wrote:
> Quoth Lennart Augustsson ,
>
>> Do you use jhc when you develop jhc? I.e., does it co
John,
Do you use jhc when you develop jhc? I.e., does it compile itself.
For me, this is the litmus test of when a compiler has become usable.
I mean, if even the developers of a compiler don't use it themselves,
why should anyone else? :)
-- Lennart
On Wed, Nov 11, 2009 at 3:37 AM,
It's not an easy problem to pretty print (i.e. change indentation) and
preserve the comments. And always get it right.
On Tue, Oct 20, 2009 at 1:28 PM, Pasqualino "Titto" Assini
wrote:
> Thanks Niklas,
>
> in fact this produced a source with comments:
>
>
> import Language.Haskell.Exts.Annotated
Yes, there are simple H-M examples that are exponential.
x0 = undefined
x1 = (x1,x1)
x2 = (x2,x2)
x3 = (x3,x3)
...
xn will have a type with 2^n type variables so it has size 2^n.
-- Lennart
On Tue, Oct 13, 2009 at 6:04 PM, Brad Larsen wrote:
> On Tue, Oct 13, 2009 at 3:37 AM, Simon Pey
what type you
give me.
The second one says, I (foo) require you (the caller) to give me an
numeric 'a' that I can use any way I want. You (the caller) don't get
to choose what type you give me, you have to give me a polymorphic
one.
-- Lennart
On Thu, Oct 8, 2009 at 5:35 PM, Bula
The reason a gets a single type is the monomorphism restriction (read
the report).
Using NoMonomorphismRestriction your example with a works fine.
On Thu, Oct 8, 2009 at 12:29 PM, Cristiano Paris wrote:
> On Thu, Oct 8, 2009 at 11:04 AM, minh thu wrote:
>> Hi,
>>
>> I'd like to know what are the
OK, "just pairs" have no arithmetic, but one way of defining
arithmetic is to treat the pairs as complex numbers. Or as mantissa
and exponent. Or as something else. So there's nothing wrong, IMO,
to make pairs an instance of Num if you so desire. (Though I'd
probably introduce a new type.)
On
too. After that, you have two choices: a)
> admit that complex numbers and double numbers are the same - and most
> mathematicians would agree they aren't - or b) admit that the relation "be
> the same" is not transitive - which is simply bizarre.
>
>
> Lennart Aug
Everyone agrees that the Haskell numeric hierarchy is flawed, but I've
yet to see a good replacement.
On Mon, Oct 5, 2009 at 4:51 PM, Brad Larsen wrote:
> On Mon, Oct 5, 2009 at 10:36 AM, Miguel Mitrofanov
> wrote:
> [...]
>> Of course, it's OK to call anything "numbers" provided that you stated
But complex numbers are just pairs of numbers. So pairs of numbers
can obviously be numbers then.
On Mon, Oct 5, 2009 at 4:40 PM, Miguel Mitrofanov wrote:
> Lennart Augustsson wrote:
>>
>> And what is a number?
>
> Can't say. You know, it's kinda funny to ask
And what is a number? Are complex numbers numbers?
On Mon, Oct 5, 2009 at 3:12 PM, Miguel Mitrofanov wrote:
>
>
> Sönke Hahn wrote:
>
>> I used to implement
>>
>> fromInteger n = (r, r) where r = fromInteger n
>>
>> , but thinking about it,
>> fromInteger n = (fromInteger n, 0)
>>
>> seems
attern.
So there's no "keep more decimals", just a matter of string conversion.
-- Lennart
On Tue, Aug 25, 2009 at 7:11 PM, Ketil Malde wrote:
> Steve writes:
>
>> Also, I had a problem using floating point in Python where
>>>>> round(697.04157958254996,
base there would be a small penalty.
-- Lennart
On Tue, Aug 25, 2009 at 3:20 PM, Henning
Thielemann wrote:
>
> On Sun, 23 Aug 2009, Lennart Augustsson wrote:
>
>> You're absolutely right. It would be easy to change logBase to have
>> special cases for, say, base 2 an
You're absolutely right. It would be easy to change logBase to have
special cases for, say, base 2 and base 10, and call the C library
functions for those. In fact, I think it's a worth while change,
since it's easy and get's better results for some cases.
-- Lennart
On
Even if you are only slightly irritated by offset syntax, why are you using it?
{;} works fine.
On Sat, Aug 22, 2009 at 3:51 AM, John D. Ramsdell wrote:
> Let me put all my cards on the table. You see, I really am only
> slightly irrigated by offset syntax. In contrast, I am a strong
> proponent
-response model. I take that as a sign that unsafePerformIO is
bad. :)
-- Lennart
On Fri, Aug 21, 2009 at 3:14 PM, Derek Elkins wrote:
> On Fri, Aug 21, 2009 at 5:04 AM, Lennart
> Augustsson wrote:
>>> On Fri, Aug 21, 2009 at 10:52 AM, Bayley, Alistair
>>> wrote:
>&g
You need a lot of magic to make the IO monad efficient.
You don't really want to pass around (and pattern match on) a
RealWorld token, that would be inefficient.
On Fri, Aug 21, 2009 at 11:04 AM, Peter Verswyvelen wrote:
> IO also seems to use unboxed (hence strict?) tuples
>
> newtype IO a = IO
means.
It's uninteresting for this discussion how GHC enforces the sequencing
internally, the important part is that it is part the sequencing is
part of the IO monad semantics and this is what should be used to
guarantee the sequencing of IO operations in a program.
-- Lennart
On Thu, Au
Using seq to control a program's semantics (as in, input-output
behaviour) is a horrible hack.
The seq operation there to control space and time aspects of your program.
(The specification of seq doesn't even say that the first argument is
evaluated before the second one.)
You should use data depen
assume your code is pure.
-- Lennart
On Tue, Aug 11, 2009 at 5:48 PM, Job Vranish wrote:
> Does anybody know if there is some unsafe IO function that would let me do
> destructive assignment?
> Something like:
>
> a = 5
> main = do
> veryUnsafeAndYouShouldNeverEveryCall
expect things to
still work.
For RecordPuns I don't have an opinion on what to do.
-- Lennart
On Sun, Aug 9, 2009 at 9:42 PM, Simon Peyton-Jones wrote:
> Oh, now I get it, thanks. This message concerns design choices for
> record-syntax-related GHC extensions. Lennart, pls tune in.
A2: Yes, this seem unfortunate, so perhaps a different definition for
Complex is warranted.
Or maybe the default implementation for (**) should be changed so that
0**x is 0, except if x is 0 (in which case I think it should be
undefined).
-- Lennart
On Sat, Aug 8, 2009 at 2:55 PM, Paul
That how I was taught to round in school, so it doesn't seem at all
unusual to me.
2009/7/23 Matthias Görgens :
>> Round-to-even means x.5 gets rounded to x if x is even and x+1 if x is
>> odd. This is sometimes known as banker's rounding.
>
> OK. That's slightly unusual indeed.
> ___
With the RecordWildCard extension you should be able to write
newFoo Old.Foo{..} = New.Foo { .., z=1 }
On Tue, Jul 28, 2009 at 3:47 PM, Henry Laxen wrote:
> Malcolm Wallace cs.york.ac.uk> writes:
>
>>
>> > and perhaps use emacs to
>> > query-replace all the Foo1's back to Foo's
>>
>> At least
Actually, keeping all names distinct is not de Bruijn numbering, it's
called the Barendregt convention.
On Sun, Jun 21, 2009 at 7:05 PM, Deniz Dogan wrote:
> 2009/6/21 Andrew Coppin :
>> OK, so I'm guessing there might be one or two (!) people around here who
>> know something about the Lambda cal
ot; during substitution, i.e., renaming the bound variables.
-- Lennart
On Sun, Jun 21, 2009 at 6:53 PM, Andrew
Coppin wrote:
> OK, so I'm guessing there might be one or two (!) people around here who
> know something about the Lambda calculus.
>
> I've written a simple interpre
Did you try running it in some debugger, like windbg or VS?
2009/6/20 Andrew Coppin :
> Marcin Kosiba wrote:
>>
>> On Saturday 20 June 2009, Andrew Coppin wrote:
>>
>>>
>>> OK, so here's an interesting problem...
>>>
>>> I've been coding away all day, but now my program is doing something
>>> slig
Use 1. You'll probably need a monad in the type checker soon or later
anyway, e.g., for handling errors.
On Sat, Jun 20, 2009 at 7:57 PM, Geoffrey Irving wrote:
> Hello,
>
> I am designing a type inference algorithm for a language with
> arbitrary function overloading. For various reasons (beyon
ot; way to go. That is not the way the creators of Haskell
> designed language though... am i missing something?
>
> On Wed, Jun 17, 2009 at 4:05 PM, Lennart
> Augustsson wrote:
>> What do you mean by "literals are strict"? Strictness is a semantic
>> p
What do you mean by "literals are strict"? Strictness is a semantic
property of functions, and while literals can be overloaded to be
functions I don't know what you mean.
On Wed, Jun 17, 2009 at 9:50 PM, Keith Sheppard wrote:
> Haskell's numeric literals are strict. You wouldn't want that to
> c
I wasn't contradicting you, just clarifying that this is indeed the
optimal asymtotic complexity.
On Mon, Jun 15, 2009 at 3:43 PM, Sebastian
Sylvan wrote:
> Is that not what I said?
>
> On Mon, Jun 15, 2009 at 2:12 PM, Lennart Augustsson
> wrote:
>>
>> A priority qu
A priority queue can't have all operations being O(1), because then
you would be able to sort in O(n) time. So O(log n) deleteMin and
O(1) for the rest is as good as it gets.
On Mon, Jun 15, 2009 at 10:40 AM, Sebastian
Sylvan wrote:
>
>
> On Mon, Jun 15, 2009 at 4:18 AM, Richard O'Keefe wrote:
>
= not (x /= y)
On Thu, May 28, 2009 at 8:14 AM, Simon Peyton-Jones
wrote:
> You are absolutely right about the tantalising opportunity. I know that
> Lennart has thought quite a bit about this very point when designing his
> Paradise system. Likewise Conal for Pan.
>
> One diffi
Type checking is decidable for all of the lambda cube, but not type inference.
Haskell 98 is a subset of Fw, Haskell with extensions is an superset of Fw.
-- Lennart
On Mon, May 25, 2009 at 12:59 PM, Brent Yorgey wrote:
> On Sun, May 24, 2009 at 10:39:50AM +0200, Petr Pudlak wrote:
>&g
Simplicity of pattern matching semantics, not of implementation (we
all knew how to implement it).
Miranda had non-linear patterns, but nobody really argued for them in Haskell.
If Haskell had them, I'd not argue to have them removed, but nor will
I argue to add them.
-- Lennart
On Fri, M
In the original language design the Haskell committee considered
allowing multiple occurrences of the same variable in a pattern (with
the suggested equality tests), but it was rejected in favour of
simplicity.
-- Lennart
On Fri, May 15, 2009 at 11:30 AM, Sittampalam, Ganesh
wrote:
> Co
But testing for something being evaluated has to be in the IO monad,
or else you're going to break the semantics.
On Fri, May 8, 2009 at 4:14 PM, Don Stewart wrote:
> Andy Gill has been advocating programmatic access to the 'is evaluated'
> status bit for years now. 'seq' becomes cheaper, and we
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