I’m currently playing around with SOE to make some simple interactive math
exercises for students. This worked fine, although I could have done this
much faster using C# (which I know very well), but since I’m addicted to
Haskell now, I used the latter language ;) Furthermore, I hope that one day,
When I read "side-effects", I understand it as "unwanted effects", like
"aliasing", and "effects depending on the order of execution". I'm not sure
if my understanding here is correct. I hope Haskell does not allow
"side-effects" but only "effects", meaning the monads do not allow you to
write the
IMHO and being a newbie having 20 years of professional C/C++/C# experience
but hardly any Haskell experience, I agree with this. I find the monad
syntax very confusing, because it looks so much like imperative code, but it
isn't. Personally I also liked the Concurrent Clean approach, although this
Thanks, that is a much clearer explanation than
http://en.wikibooks.org/wiki/Haskell/Phantom_types
Peter
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Arie Peterson
Sent: Wednesday, August 08, 2007 5:59 PM
To: haskell-cafe@haskell.org
Subject: Re: [Hask
I’m having difficulty to understand what phantom types are good for. Is this
just for improving runtime performance?
I read the wiki, and it says "this is useful if you want to increase the
type-safety of your code", but the code below does not give a compiler error
for the function test1, I get
This is very nice, but it does not really solve the original problem.
In your code, evaluating
collide (Jupiter, Asteroid)
will result in an endless loop. This is expected in your code, because no
"inheritance" relation is present between e.g Jupiter and Planet. With
multi-dispatch, it should pi
In de book Modern C++ design, Andrei Alexandrescu writes that Haskell
supports “multi-methods”
http://books.google.com/books?id=aJ1av7UFBPwC&pg=PA3&ots=YPiJ_nWi6Y&dq=moder
n+C%2B%2B&sig=FWO6SVfIrgtCWifj9yYHj3bnplQ#PPA263,M1
How is this actually done in Haskell? Maybe this is just a basic feature
IMHO although this is a great explanation of what a monad is (as far as I
understand it), for newbies I think it helps a lot to first look at the
specific cases where monads are used and why they are invented, as explained in
http://sigfpe.blogspot.com/2006/08/you-could-have-invented-monads-and.
Kaveh> "A monad is like a loop that can run a new function against its variable
in each iteration."
I’m an imperative programmer learning Haskell, so I’m a newbie, but I’ll give
it a try ☺ Making mistakes is the best way to learn it ;)
There are lots of different kinds of monads, but let’s sti
Thanks! Is this is also the case when using let and where, or is this just
syntactic sugar?
-Original Message-
From: Jules Bean [mailto:[EMAIL PROTECTED]
Sent: Tuesday, July 31, 2007 5:09 PM
To: Bryan Burgers
Cc: peterv; haskell-cafe@haskell.org
Subject: Re: [Haskell-cafe] Newbie
Having only a couple of days of practice programming Haskell (but having
read lots of books and docs), I find myself writing very explicit low level
code using inner "aux" functions (accumulators and loops). Then I force
myself to revise the code, replacing these aux functions with suitable
higher
Does Haskell support any form of automatic memorization?
For example, does the function
iterate f x
which expands to
[x, f(x), f(f(x)), f(f(f(x))), …
gets slower and slower each iteration, or can it take advantage of the fact
that f is referentially transparent and hence can be
Yes, for a newbie like me it was actually the reason to abandon Haskell
initially; none of the examples at http://www.haskell.org/HOpenGL compiled!
Another very cool albeit difficult project would be automatic retargeting of
Haskell code to the graphics processor unit (GPU), or IBM Synergistic
Pro
at Ziganshin [mailto:[EMAIL PROTECTED]
Sent: Friday, July 13, 2007 6:43 PM
To: peterv
Cc: 'Lukas Mai'; haskell-cafe@haskell.org
Subject: Re[2]: [Haskell-cafe] Newbie question about tuples
Hello peterv,
Friday, July 13, 2007, 5:03:00 PM, you wrote:
> think the latest compilers are mu
Super. This is really a great mailing list :)
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Chung-chieh Shan
Sent: Friday, July 13, 2007 16:54
To: haskell-cafe@haskell.org
Subject: [Haskell-cafe] Re: Newbie question about tuples
peterv <[EM
g
problem says it's not *generally* possible?
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Jonathan Cast
Sent: Friday, July 13, 2007 16:21
To: haskell-cafe@haskell.org
Subject: Re: [Haskell-cafe] Newbie question about tuples
On Friday 13 July 2007, peterv w
I'm beginning to see that my old implementation in C++ clutters my Haskell
design.
You see, in C++ I can write:
// A vector is an array of fixed-length N and elements of type T
template struct Vector
{
T Element[N];
friend T dot(const Vector& a, const Vector& b)
{
T result = 0;
zzy talk from a newbie trying to look
impressive ;)
-Original Message-
From: Benja Fallenstein [mailto:[EMAIL PROTECTED]
Sent: Thursday, July 12, 2007 3:11 PM
To: peterv
Cc: Henning Thielemann; Haskell-Cafe@haskell.org
Subject: Re: [Haskell-cafe] Functional dependencies *not* part of the n
g these funcdeps, are they "ill" as the "rumor" goes?
Thanks,
Peter
-Original Message-
From: Henning Thielemann [mailto:[EMAIL PROTECTED]
Sent: Thursday, July 12, 2007 11:44 AM
To: peterv
Cc: Haskell-Cafe@haskell.org
Subject: Re: [Haskell-cafe] Functional depende
I tried to do something in CAL that I could not solve without functional
dependencies. In their support forum, it got mentioned that func.deps
propably won't make into the next Haskell standard... Any comments on that?
Now, the thing I tried to solve was:
data Vector2 a = Num a => V2 a a
Hi,
I have a couple of questions about tuples.
Q1) Is it possible to treat a tuple of N elements in a generic way? So
instead of writing functions like lift1 e1, lift2 (e1,e2), lift3 (e1,e2,e3)
just one function liftN that works on tuples of any length?
Q2) (Maybe related to Q1) Can I convert a
riginal Message-
From: Donald Bruce Stewart [mailto:[EMAIL PROTECTED]
Sent: Friday, July 06, 2007 11:22
To: peterv
Cc: 'Bulat Ziganshin'; haskell-cafe@haskell.org
Subject: Re: [Haskell-cafe] RE: Modern Haskell books (was "Re: A very
nontrivial parser")
dons:
> bf3:
> &
> but afair you don't yet have too much experience even with H98
> language? from my POV, H98 as is useful for learning, but not for real
> apps. there is wide common subset of GHC and Hugs language extensions
> and this set (with exception for FD) will probably become new Haskell'
> standard
The
In Haskell, currying can only be done on the last (rightmost) function
arguments.
So
foo x y
can be curried as
foo x
but not as
foo ? y
where ? would be a "wilcard" for the x parameter.
In Haskell, one must write a new function
foo2 y x = foo x y
and then
I vaguely remember to have read that HGL is (currently) not supported on
Windows, but I can't find this information any more.
Is this correct? It seems not to be included in GHC 6.6
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
quot; magic worked fine, thanks!
-Original Message-
From: Thomas Schilling [mailto:[EMAIL PROTECTED]
Sent: Thursday, June 28, 2007 9:40 PM
To: peterv
Cc: Haskell-Cafe@haskell.org
Subject: Re: [Haskell-cafe] Newbie question: alternative for toInt/fromInt
toInt = id
fromInt = id
?
On 28
I'm trying to get the SOE graphics library to compile for Win32 using the
latest libraries.
I fixed a couple of imports, but in the file GraphicsTypes.hs, the functions
toInt/fromInt are used, which are now obsolete:
type Dimension = Int
toDimension:: Win32.INT -> Dimension
fromDimens
; a -> b
With your encouragements, I'll keep pluuging. Thanks.
- br
On 6/27/07, peterv <[EMAIL PROTECTED]> wrote:
I'm also a haskell newbie, but I'll try to help; the experts here will
correct me if I'm wrong.
The compiler cannot in all cases infer the type of a numbe
I'm also a haskell newbie, but I'll try to help; the experts here will
correct me if I'm wrong.
The compiler cannot in all cases infer the type of a number. pi can be a
Float, a Double, or even a complex number.
Furthermore unlike in C/C++ you cannot just mix integer and floating
operations.
Fo
I'm baffled. So using the Arrow abstraction (which I don't know yet) would
solve this problem? How can (perfectActionB x) be checked with without ever
executing performActionA which evaluates to x? This can only be done when x
is a constant expression no?
-Original Message-
From: [EMAIL PR
Wow thanks for all the info! This certainly can get me started.
And yet I have some more questions (sorry!):
- Unfortunately this project won't be open source; if my first tests are
successful, I will try to convince my employer (who wants to develop such a
graphical language) to use Haskell for
Hi,
Since nobody gave an answer on this topic, I guess it is insane to do it in
Haskell (at least for a newbie)? :)
Thanks for any info,
Peter
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of peterv
Sent: Wednesday, June 20, 2007 21:48
To: haskell-cafe
So float math in *slower* than double math in Haskell? That is interesting.
Why is that?
BTW, does Haskell support 80-bit "long double"s? The Intel CPU seems to use
that format internally.
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Philip Armstro
In the book "Haskell School of Expression", streams are nicely explained
using a graphical flow graph.
This is also done more or less in
http://research.microsoft.com/~simonpj/papers/marktoberdorf/Marktoberdorf.pp
t to explain monads and other concepts.
I would like to create a program that allow
at trying to make the SOE stuff work with the
threaded runtime system by using the primitives Gtk2Hs provides to use
Gtk+ safely from multiple threads.
Duncan"
-Original Message-
From: David House [mailto:[EMAIL PROTECTED]
Sent: Wednesday, June 20, 2007 6:42 PM
To: peterv
Cc: 'D
> (which just states that record type and field label type together uniquely
determine the field value type)
That's nice. When will a new Haskell standard become official? It seems so
many new extensions exist, that one cannot judge the language by looking at
"Haskell98" anymore.
> in practice, o
Super! Would be nice if this gets build into GHC/GHCI :)
-Original Message-
From: Neil Mitchell [mailto:[EMAIL PROTECTED]
Sent: Wednesday, June 20, 2007 01:07
To: Felipe Almeida Lessa
Cc: peterv; haskell-cafe@haskell.org
Subject: Re: [Haskell-cafe] Avoiding "Non-exhaustive patter
> Sounds like it was difficult. Could you describe what you tried
Actually, it was easy once I switched from xemacs to emacs... Of course, I
missed the part in the wiki that xemacs does not work without some changes, mea
culpa. The reason I used xemacs was because the previous version of emacs
ssage-
From: Jules Bean [mailto:[EMAIL PROTECTED]
Sent: Tuesday, June 19, 2007 09:58
To: peterv
Cc: 'David House'; haskell-cafe@haskell.org
Subject: Re: [Haskell-cafe] Haskell mode for emacs - some questions
peterv wrote:
> And when I will me using HopenGL, I will want perform
Haskell is known for its very strong static type checking, which eliminates
a lot of runtime errors.
But the following simple program crashes at runtime:
data D = A | B
f A = True
main = print (f B)
I understand this has nothing to do with type checking, but why can't the
compiler giv
mming
videogames or special effects, you have to run and test a lot, because what
you see on screen usually
determines your next actions.
-Original Message-
From: David House [mailto:[EMAIL PROTECTED]
Sent: Tuesday, June 19, 2007 12:34 AM
To: peterv
Cc: haskell-cafe@haskell.org
Subjec
ion, which is a
pain (forgive me if I'm using incorrect terms here, I come from the OO
world...) Personally I like that, but that's a question of taste I guess.
Peter
-Original Message-
From: Bulat Ziganshin [mailto:[EMAIL PROTECTED]
Sent: Tuesday, June 19, 2007 8:39 AM
To: pete
I finally got emacs using Haskell-mode working. It seems that the latest
version of emacs support nice font smoothing on Windows; the last time I
looked it didn't. Auto indent works, inf-haskell works, really great. So far
so good.
But I have some questions I did not find in the wiki:
- How can I
That looks cool.
Just another wild idea which I might find useful, but is more like
refactoring, is to convert the fields of a record to get/set type-classes,
and refactor all usages of those fields.
So
---
data Person = Person { name :: String, age :: Float }
main = print $ na
Well, yes and no.
Such an IDE does not have to follow the guidelines, because as you said,
these are “flexible”. Take Microsoft Office 2007, completely new GUI,
shocked the world.
But take Eclipse. This is a fairly standard GUI, mostly the same on unix,
mac, and Windows.
IMHO, for a
Well, if I was 15 again and had no RSI in both arms, I certainly would
create a basic IDE as my first Haskell project, it would be fun ;) I've
looked at the code of Visual Haskell, but I'm not (yet/ever?) capable of
enhancing it (the Haskell part, the COM/C++ part is a lot easier for me). So
it's a
Thanks for the nice info. I'm going to give it another try then...
When I said I don't want to learn Emacs, I meant not learning its LISP
architecture with the goal of creating my own custom Emacs...
OT: The reasons I'm looking at Haskell are:
- the object oriented approach failed for me when w
Another feature which would be cool for an IDE is: "implement instance". So
you automatically get to see all the functions of a type class you need to
implement. Using C#/Java, this is used all over the place.
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.5
I just tried the Haskell Mode using xemacs, adjust my init.el file, loaded
my haskell file, and got great syntax highlighting! So far so good.
But people, emacs is so weird for a Windows user...
For example, ALL windows (and motif?) programs use CTRL-Z for undo. But not
emacs... So after som
Indeed, that's what I forgot to mention, Resharper in Visual Studio 2005
does that for C#, IntelliJ & Eclipse for Java. You rarely need compilation,
its syntax checker runs inplace and incrementally and shows you the errors
and warning in the right margin. That saves you a lot of time.
For Haskel
Thank for the reply.
I'll try the emacs approach (or better Xemacs because Emacs on Windows has
really ugly font smoothing), but I must say that - being an old school
object-oriented programmer who got spoiled by fully integrated IDEs like
Borland's TurboPascal, Microsoft Visual Studio, and Eclip
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