Awesome! Congratulations on the first release, I look forward to working with
it. Also, the web design is great, possibly the best designed Haskell library
website I've seen so far.
-chris
On 22 mei 2010, at 07:25, Gregory Collins wrote:
Hello all,
To coincide with Hac Phi 2010
On Sat, 2010-05-22 at 00:15 +, R J wrote:
I'm trying to prove that (==) is reflexive, symmetric, and transitive
over the Bools, given this definition:
(==) :: Bool - Bool - Bool
x == y = (x y) || (not x not y)
My question is: are the
R J rj248...@hotmail.com writes:
I'm trying to prove that (==) is reflexive, symmetric, and
transitive over the Bools, given this definition:
(==):: Bool - Bool - Bool
x == y = (x y) || (not x not y)
Since Bool is a type, and all Haskell types include ⊥, you need
to add conditions in
When I run cabal update on my Mac (Snow Leopard, Intel), I get:
% cabal update
Downloading the latest package list from hackage.haskell.org
cabal: Codec.Compression.Zlib: incompatible zlib version
Anyone else seeing this? Reinstalling the Haskell Platform hasn't helped.
Thanks!
Bill Atkins watk...@alum.rpi.edu writes:
When I run cabal update on my Mac (Snow Leopard, Intel), I get:
% cabal update
Downloading the latest package list from hackage.haskell.org
cabal: Codec.Compression.Zlib: incompatible zlib version
I'm going to randomly guess that the version of the C
Richard,
I found this very annoying when I first realised GHC doesn't do any CSE,
given that the result of pure functions only depend on their parameters.
Even though CSE usually sounds good, when you ask, they go and find obscure
examples in which it causes great trouble :)
I think, there
Hello,
Even though CSE usually sounds good, when you ask, they go and find obscure
examples in which it causes great trouble :)
Do you (or others) have any particular mean but understandable example?
Cheers,
Michael
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Haskell-Cafe mailing list
Michael Lesniak mlesn...@uni-kassel.de writes:
Even though CSE usually sounds good, when you ask, they go and find obscure
examples in which it causes great trouble :)
Do you (or others) have any particular mean but understandable
example?
Hello,
http://www.haskell.org/haskellwiki/GHC:FAQ#Does_GHC_do_common_subexpression_elimination.3F
All hail Google! :p
You're right :D. Thanks!
- Michael
--
Dipl.-Inf. Michael C. Lesniak
University of Kassel
Programming Languages / Methodologies Research Group
Department of Computer Science
enDataI :: (Int - DataBox)
enDataI = DataBox
enDataB :: (Bool - DataBox)
enDataB = DataBox
instance Data DataBox where
gfoldl k z (DataBox d) = z DataBox `k` d
gunfold k z c = (if True then k (z enDataI) else k (z enDataB))
Interesting solution but I'm not smart enough to see how
I have a different problem (also after doing a cabal update): I get a bus
error. I just created this ticket for it:
http://hackage.haskell.org/trac/hackage/ticket/691
-chris
On 22 mei 2010, at 13:20, Bill Atkins wrote:
When I run cabal update on my Mac (Snow Leopard, Intel), I get:
%
On Saturday 22 May 2010 15:00:25, Thomas Schilling wrote:
Actually, in this case it would be safe to do CSS. Because
a) the function is strict in both arguments so GHC creates a worker
which only uses unboxed types
b) this cannot cause any space leaks (it contains no pointers)
The
On Saturday 22 May 2010 16:48:27, Daniel Fischer wrote:
The boxing is due to the use of (^).
If you write x*x instead of x^2, it can use the primop *## and needn't
box it.
As a side effect, the original time leak probably wouldn't have occured
with x*x instead of x^2 because one would've made
On May 22, 2010, at 08:30 , Ozgur Akgun wrote:
Even though CSE usually sounds good, when you ask, they go and find
obscure examples in which it causes great trouble :)
They're not actually that obscure. Most of them can be summarized
thusly: anything that would cause a fold to cause a
On May 22, 2010, at 1:32 AM, Jon Fairbairn wrote:
Since Bool is a type, and all Haskell types include ⊥, you need
to add conditions in your proofs to exclude it.
Not really. Bottom isn't a value, so much as an expression for
computations that don't refer to real values. It's close enough
On 22 May 2010 16:06, Daniel Fischer daniel.is.fisc...@web.de wrote:
On Saturday 22 May 2010 16:48:27, Daniel Fischer wrote:
The boxing is due to the use of (^).
If you write x*x instead of x^2, it can use the primop *## and needn't
box it.
As a side effect, the original time leak probably
Note that all (True ==) is logically equivalent to all id and to
the and function from the prelude.
A more general approach based on type classes, the function taut takes
a boolean function and determines (by exhaustive search) if it is a
tautology:
class BooleanFunction a where
taut :: a -
Congratulations on the release. I was interested in seeing how this would
work as a WAI handler, and came across some questions:
* I noticed that the Method datatype is restricted to a set of specific
methods. Seeing as the list of methods can be expanded[1], why was this
chosen?
* The
Michael Snoyman mich...@snoyman.com writes:
Congratulations on the release. I was interested in seeing how this
would work as a WAI handler, and came across some questions:
* I noticed that the Method datatype is restricted to a set of
specific methods. Seeing as the list of methods can be
On Sat, May 22, 2010 at 11:15 PM, Gregory Collins
g...@gregorycollins.netwrote:
Michael Snoyman mich...@snoyman.com writes:
Congratulations on the release. I was interested in seeing how this
would work as a WAI handler, and came across some questions:
* I noticed that the Method
Michael Snoyman mich...@snoyman.com writes:
Would you accept:
ciToLower :: CIByteString - ByteString
instead? I prefer opaque datatypes in general. We didn't see a need for
that use-case, the idea was that the string representation would be the
same but we
There are many libraries to write function takes an record has Foo
and Bar and returns something. But writing type of the function is
still difficult. I can't write such types using HList or records
without reading documents. I think, using has, There's few effort to
write such types.
In
I did some more digging around and it would seem that the error was being
printed from the load call (depanal does some parsing ofcourse to find the
imports).
I managed to silence that using loadWithLogger (const $ return ())
LoadAllTargets (maybe all these loggers should be consolidated).
I'm using Project Euler to learn Haskell. In particular, I'm writing a
program for Problem 18:
http://projecteuler.net/index.php?section=problemsid=18. As a solution, I'm
constructing a list, containing maximum sums of values on a path from top of
the triangle to a given item. In this list, item
Right, that modulename was being printed due to a trace statement in my code,
so I’m now using withLocalCallbacks (\_ - GhcApiCallbacks (\_ _ - return ()))
$
To override everything along with setting log_action to (\_ _ _ _ - return
()). Now nothing else gets printed J
Thanks for all the
On Sunday 23 May 2010 01:10:54, Vladimir Ch. wrote:
I'm using Project Euler to learn Haskell. In particular, I'm writing a
program for Problem 18:
snip
The program works, but consumes obscene amount of memory.
Not if it's compiled. Even interpreted I wouldn't call it obscene, though
it is
On 21 May 2010 01:58, Carlos Camarao carlos.cama...@gmail.com wrote:
But this type-correct program would become not typeable if
instances such as the ones referred to before (by Daniel Fischer) ...
It seems that single param type classes enjoy a nice property: ...
* Adding an instance to
Not really. Your problem is that you calculate maxPaths vals over and over
again in
where mpath i val = val + maximum [(maxPaths vals) !! pi| pi - prev i]
; the value isn't shared (it is, if compiled with optimisations).
If you share the list by giving it a name, your programme becomes much
Hi.
I'm a Haskell newbie, and I've been reading Oleg's work about
lightweight dependent types in Haskell, and I've been trying to figure
out if I understand how branding works (warning bells already, I
know).
At http://okmij.org/ftp/Computation/lightweight-dependent-typing.html#Branding,
he
On Sun, May 23, 2010 at 1:36 AM, Gregory Collins g...@gregorycollins.netwrote:
Michael Snoyman mich...@snoyman.com writes:
If the POST body has content-type application/x-www-form-urlencoded
we
parse it for you and put the fields in the parameter mapping. If this
isn't your
Hi All,
I am a newbie to Haskell, and have been using Programming in Haskell along
with Eric Meijer videos covering the book syllabus. I am currently on
Chapter 8 Functional Parsers, and trying to implement few of the examples
given in the book.
Following is the example :
item = \inp - case inp
On Sat, May 22, 2010 at 8:36 PM, Dave Neuer dave.ne...@pobox.com wrote:
Hi.
I'm a Haskell newbie, and I've been reading Oleg's work about
lightweight dependent types in Haskell, and I've been trying to figure
out if I understand how branding works (warning bells already, I
know).
At
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