On Wed, Sep 16, 2009 at 11:58 AM, Cristiano Paris fr...@theshire.orgwrote:
On Wed, Sep 16, 2009 at 7:12 PM, Ryan Ingram ryani.s...@gmail.com wrote:
Here's the difference between these two types:
test1 :: forall a. a - Int
-- The caller of test1 determines the type for test1
test2 ::
Yes that worked.
--- On Wed, 9/16/09, Paulo Tanimoto tanim...@arizona.edu wrote:
From: Paulo Tanimoto tanim...@arizona.edu
Subject: Re: [Haskell-cafe] Can't install Haskell Platform (Ubuntu 9.02)
To: Gregory Propf gregorypr...@yahoo.com
Cc: Haskell-Cafe haskell-cafe@haskell.org
Date: Wednesday,
I now have the Haskell platform install problem solved but I'm now trying to
get the leksah IDE installed and I'm getting this.
runhaskell Setup configure
Configuring leksah-0.6.1...
Setup: At least the following dependencies are missing:
glib =0.10, gtk =0.10, gtksourceview2 =0.10.0
I am aware
On Thu, Sep 17, 2009 at 9:01 AM, Gregory Propf gregorypr...@yahoo.com wrote:
I now have the Haskell platform install problem solved but I'm now trying to
get the leksah IDE installed and I'm getting this.
runhaskell Setup configure
Configuring leksah-0.6.1...
Setup: At least the following
Does anybody know where I can find a non-fee-based version of Paul
Hudak's paper, Conception, evolution, and application of functional
programming languages [1]? There used to be a version that did not
require an ACM account available at
Hello Neil
I used System.FilePath.Posix quite extensively recently, and I thank
you for the package filepath. There were however two words that I
needed which I could not construct from those in
System.FilePath.Posix. They are maybe of interest to you and others.
I submit these two words to
Today I received the request below. At first the URL confused me, but
apparently www.haskell.org is known under two names :-)
The request should probably be handled by someone involved in ICFP.
/M
On Wed, Sep 16, 2009 at 11:53 PM, Peter Green peter.gr...@frixo.com wrote:
Hi,
I was wondering
I'm pleased to announce version 2999.5.1.0 [1] of the graphviz library,
which provides bindings to the GraphViz [2] suite of tools for drawing
graphs.
[1] http://hackage.haskell.org/package/graphviz-2999.5.1.0
[2] http://www.graphviz.org/
This is mainly a bug-fix release; as such, there is no
There's no such named package in Hackage though. That was the first thing I
looked for. All Hackage has with the string gtk2hs is this stuff
gtk2hs-cast-glade library: A type class for cast functions of Gtk2hs: glade
packagegtk2hs-cast-glib library: A type class for cast functions of Gtk2hs:
Am Donnerstag 17 September 2009 12:35:19 schrieb Gregory Propf:
There's no such named package in Hackage though. That was the first thing
I looked for. All Hackage has with the string gtk2hs is this stuff
AFAIK, gtk2hs is not yet cabalized and not on Hackage, look at
Hi all. This email is in literate Haskell; you should be able to load
it into ghci and verify what I'm saying (nb: it won't compile without
alteration: see below).
I'm trying to do something which may anyway be stupid / not the best
approach to what I'm trying to achieve; however, it's not
Hey Andy,
On Thu, Sep 17, 2009 at 15:40, Andy Gimblett hask...@gimbo.org.uk wrote:
Now, some of those algebraic data type types happen to be
enumerations; in this case, my idea is to list the constructors, with
the rule that each constructor's position in the list is the Int which
gets
On Thu, Sep 17, 2009 at 8:36 AM, Ryan Ingram ryani.s...@gmail.com wrote:
...
Explicitly:
Haskell:
test1 :: forall a. a - Int
test1 _ = 1
test2 :: (forall a. a) - Int
test2 x = x
explicitly in System F:
test1 = /\a \(x :: a). 1
test2 = \(x :: forall a. a). x @Int
/\ is type-level
Am Donnerstag 17 September 2009 15:56:03 schrieb José Pedro Magalhães:
Hey Andy,
On Thu, Sep 17, 2009 at 15:40, Andy Gimblett hask...@gimbo.org.uk wrote:
Now, some of those algebraic data type types happen to be
enumerations; in this case, my idea is to list the constructors, with
the
Hello,
On Thu, Sep 17, 2009 at 16:05, Daniel Fischer daniel.is.fisc...@web.dewrote:
Am Donnerstag 17 September 2009 15:56:03 schrieb José Pedro Magalhães:
Hey Andy,
On Thu, Sep 17, 2009 at 15:40, Andy Gimblett hask...@gimbo.org.uk
wrote:
Now, some of those algebraic data type types
On 17 Sep 2009, at 15:21, José Pedro Magalhães wrote:
E.g. here's a type Bar with three constructors:
data Bar = X | Y | Z deriving (Show)
instance Enumerated Bar where
constructors = [X, Y, Z]
(This is certainly ugly. Any suggestions?)
|constructors| is expressible in
Am Donnerstag 17 September 2009 16:30:14 schrieb Andy Gimblett:
On 17 Sep 2009, at 15:21, José Pedro Magalhães wrote:
E.g. here's a type Bar with three constructors:
data Bar = X | Y | Z deriving (Show)
instance Enumerated Bar where
constructors = [X, Y, Z]
(This is
Remember that there is asymmetry between (+) and (-). The former has the
commutative property and the latter does not so:
(+) 3 4 = 7
and
(+) 4 3 = 7
but
(-) 3 4 = -1
and
(-) 4 3 = 1
--- On Thu, 9/17/09, Tom Doris tomdo...@gmail.com wrote:
From: Tom Doris tomdo...@gmail.com
Subject:
Does anybody know where I can find a non-fee-based version of Paul
Hudak's paper, Conception, evolution, and application of functional
programming languages [1]? There used to be a version that did not
seems you can get a djvu copy here
http://lib.org.by/info/Cs_Computer
Am Donnerstag 17 September 2009 15:40:10 schrieb Andy Gimblett:
instance (Enumerated a) = Target a where
convert n | n `elem` [0..len-1] = Just $ constructors !! n
| otherwise = Nothing
where len = length constructors
Yes, the second appearance of
On 2009-09-17, at 1:41 AM, Benjamin L.Russell wrote:
Does anybody know where I can find a non-fee-based version of Paul
Hudak's paper, Conception, evolution, and application of functional
programming languages [1]?
When in doubt, check citeseer.
On 17 Sep 2009, at 16:50, Daniel Fischer wrote:
Yes, the second appearance of 'constructors' is at an unspecified
type.
instance (Enumerated a) = Target a where
convert n
| n 0 = Nothing
| otherwise = case drop n constructors of
(x:_) - Just x
(-) happens to be the only prefix operator in haskell, it also an infix
operator.
so:
4 - 2
2
-3
-3
((-) 5) 3 -- note that in this case (-) is treated like any regular
function so 5 is the first parameter
2
(5 - ) 3
2
(-5 )
-5
(flip (-) 5) 3
-2
It's a little wart brought about by the
2009/9/17 Joost Kremers joostkrem...@fastmail.fm
Hi all,
I've just started learning Haskell and while experimenting with map a bit, I
ran
into something I don't understand. The following commands do what I'd expect:
Prelude map (+ 1) [1,2,3,4]
[2,3,4,5]
Prelude map (* 2) [1,2,3,4]
On Thu, Sep 17, 2009 at 6:59 AM, Cristiano Paris fr...@theshire.org wrote:
On Thu, Sep 17, 2009 at 8:36 AM, Ryan Ingram ryani.s...@gmail.com wrote:
...
Explicitly:
Haskell:
test1 :: forall a. a - Int
test1 _ = 1
test2 :: (forall a. a) - Int
test2 x = x
explicitly in System F:
Am Donnerstag 17 September 2009 18:01:36 schrieb Andy Gimblett:
On 17 Sep 2009, at 16:50, Daniel Fischer wrote:
Yes, the second appearance of 'constructors' is at an unspecified
type.
instance (Enumerated a) = Target a where
convert n
| n 0 = Nothing
|
Here's a way that works more closely to your original version:
instance Enumerated a = Target a where
convert n
| n = 0 n numConstrs = Just (constrs !! n)
| otherwise = Nothing
where
constrs = constructors
numConstrs = length constrs
Alternatively:
instance
What are you trying to use this for? It seems to me that for memo tables you
almost never have references to they keys outside the lookup table since the
keys are usually computed right at the last minute, and then discarded
(otherwise it might be easier to just cache stuff outside the function).
Hi,
Below are two attempts to define Peano arithmetic in Haskell.
The first attempt, Peano1, consists of just a signature in the class
with the axioms in the instance. In the second attempt, Peano2, I am
trying to move the axioms into the class. The reason is, I want to put
as much specification
On Tue, Sep 15, 2009 at 11:31 PM, Daniel Fischer
daniel.is.fisc...@web.de wrote:
...
Yeah, you do *not* want the whole file to be read here, except above for
testing purposes.
That's not true. Sometimes I want to, sometimes don't. But I want to
use the same code for reading files and exploit
The problem is that you are using 'suc' as if it is a constructor: ((suc m)
`eq` (suc n) = m `eq` n)
You'll have to change it to something else, and it will probably require
adding an unpacking function to your class and it will probably be messy.
I'd suggest you make use of the Eq typeclass and
Dear Programmers,
Someone just asked me to give my opinion on Noop's composition
proposalhttp://code.google.com/p/noop/wiki/ProposalForComposition.
It reminds me a little bit of
Selfhttp://en.wikipedia.org/wiki/Self_%28programming_language%29which
found its way into JavaScript. It also reminds me
Am Donnerstag 17 September 2009 21:07:28 schrieb Cristiano Paris:
On Tue, Sep 15, 2009 at 11:31 PM, Daniel Fischer
daniel.is.fisc...@web.de wrote:
...
Yeah, you do *not* want the whole file to be read here, except above for
testing purposes.
That's not true. Sometimes I want to,
On Thu, Sep 17, 2009 at 10:01 PM, Daniel Fischer
daniel.is.fisc...@web.de wrote:
...
readBit fn = do
txt - readFile fn
let (l,_:bdy) = span (/= '\n') txt
return $ Bit (read l) bdy
?
With
main = do
args - getArgs
let n = case args of
(a:_) - read a
Iain Alexander wrote:
You might want to take a look at
RFC 2445
Internet Calendaring and Scheduling Core Object Specification
Section 4.8.5.4 Recurrence Rule
Another source of inspiration might be the syntax used in remind[1].
/M
[1]: http://www.roaringpenguin.com/products/remind
--
Magnus
I don't understand your goal. Isn't Peano arithmetic summarized in Haskell as:
data Peano = Zero | Succ Peano deriving Eq
This corresponds to a first-order logic over a signature that has
equality, a constant symbol 0, and a one-place successor function
symbol S.
Function symbols such as and
Package cmu 1.1 provides unification in a commutative monoid, also
know as ACU-unification. The core computation finds the minimal
non-zero solutions to homogeneous linear Diaphantine equations. The
linear equation solver has been place in a separate module so it can
be used for other
Am Donnerstag 17 September 2009 22:20:55 schrieb Cristiano Paris:
On Thu, Sep 17, 2009 at 10:01 PM, Daniel Fischer
daniel.is.fisc...@web.de wrote:
...
readBit fn = do
txt - readFile fn
let (l,_:bdy) = span (/= '\n') txt
return $ Bit (read l) bdy
?
With
main = do
Hello
Lets say I have a library in C with a header like this:
#include stdio.h
/*really big structure*/
typedef struct {
int *a;
int *b;
/*lots of stuff
...
*/
int *z;
} foo;
/*this function allocate memory and fill the structure, reading from a
file*/
int create_foo(foo *f,FILE *file,int
In my case, the results of each computation are used to generate a node
in a graph structure (dag). The key, oddly, is a hash of a two-tuple
that gets stored in the data structure after the computation of the
node finishes. If I don't memoize the function to build a node, the
cost of generating
typedef struct {
int *a;
int *b;
/*lots of stuff
...
*/
int *z;
} foo;
int create_foo(foo *f,FILE *file,int x,int y);
int use_foo(foo *f,int w);
int destroy_foo(foo *f);
newtype Foo = Foo ()
foreign import ccall static foo.h create_foo
c_create_foo :: Ptr (Foo) - Ptr (CFile) - CInt - CInt - IO
Hi, I am trying to get the function showMinProp to return String, but I
always get an error of parse error (possibly incorrect indentation)
Who can help with this? any idea?
Thank u in advance!
data Prop
= Var String
| Negation Prop
| BinOp Op Prop Prop
data Op = And | Or | Implies | Equiv
Am Freitag 18 September 2009 02:17:22 schrieb xu zhang:
showMinProp :: Int - Prop - String
showMinProp preNo (BinOp op p q) =
case op of
And - let a = 4
Or - let a = 3
Implies - let a = 2
Equiv - let a = 1
if (a preNo)
then
Cristiano Paris wrote:
On Wed, Sep 16, 2009 at 7:12 PM, Ryan Ingram ryani.s...@gmail.com wrote:
Here's the difference between these two types:
test1 :: forall a. a - Int
-- The caller of test1 determines the type for test1
test2 :: (forall a. a) - Int
-- The internals of test2 determines what
Hi,
I'm getting different behavior in ghci and ghc with the identifier ∀. In
ghc I need
to wrap it with parens, as in
(∀) :: Var - Base - Formula - Formula
(∀) = All
In ghci, I get an error this way
Formula.lhs:112:2:
Invalid type signature
In ghci I can do
∀ :: Var - Base -
Am Freitag 18 September 2009 03:31:13 schrieb Sean McLaughlin:
Hi,
I'm getting different behavior in ghci and ghc with the identifier ∀. In
ghc I need
to wrap it with parens, as in
(∀) :: Var - Base - Formula - Formula
(∀) = All
In ghci, I get an error this way
Formula.lhs:112:2:
Hi Daniel,
Would you try putting that in a file and loading it in ghci? Your
example also works for me.
Prelude let (∀) = 5
Prelude (∀)
5
Sean
On Thu, Sep 17, 2009 at 9:41 PM, Daniel Fischer daniel.is.fisc...@web.dewrote:
Am Freitag 18 September 2009 03:31:13 schrieb Sean McLaughlin:
Hi,
Am Freitag 18 September 2009 03:51:40 schrieb Sean McLaughlin:
Hi Daniel,
Would you try putting that in a file and loading it in ghci? Your
example also works for me.
Prelude let (∀) = 5
Prelude (∀)
5
Sean
Sure:
da...@linux-mkk1:~/Haskell/CafeTesting cat Forall.hs
module Forall where
I am confused about why this thread is talking about unsafePerformIO at
all. It seems like everything you all want to do can be accomplished with
the much less evil unsafeInterleaveIO instead. (Which is still a bit evil;
but it's the difference between stealing cookies from the cookie jar and
Heh, perhaps we should petition to have a new computer key and symbol added to
the world's way of writing maths, something like maybe a downward angled slash
to mean prefix (-)
:)
--- On Thu, 9/17/09, Job Vranish jvran...@gmail.com wrote:
From: Job Vranish jvran...@gmail.com
Subject: Re:
On Thu, 17 Sep 2009 08:55:19 -0700, John Melesky
l...@phaedrusdeinus.org wrote:
On 2009-09-17, at 1:41 AM, Benjamin L.Russell wrote:
Does anybody know where I can find a non-fee-based version of Paul
Hudak's paper, Conception, evolution, and application of functional
programming languages [1]?
Weird. OK, thanks a lot! I'm switching to ¥ until I get this figured out.
Sean
On Thu, Sep 17, 2009 at 10:00 PM, Daniel Fischer
daniel.is.fisc...@web.dewrote:
Am Freitag 18 September 2009 03:51:40 schrieb Sean McLaughlin:
Hi Daniel,
Would you try putting that in a file and loading it
I'm working on a GUI application in qtHaskell, and I have a bit of a bind.
Using ghci, it launches quickly but runs slowly. On the other hand,
compiling (mainly linking) takes a while---several minutes. The truth is
that I can compile it much faster if I selectively import the needed
modules,
Am Friday 18 September 2009 04:41:13 schrieben Sie:
Weird. OK, thanks a lot! I'm switching to ¥ until I get this figured
out. Sean
What does your ghci say for
Data.Char.isSymbol (toEnum 8704) ?
___
Haskell-Cafe mailing list
Am Freitag 18 September 2009 04:06:11 schrieb Ryan Ingram:
I am confused about why this thread is talking about unsafePerformIO at
all. It seems like everything you all want to do can be accomplished with
the much less evil unsafeInterleaveIO instead. (Which is still a bit evil;
but it's the
Am Freitag 18 September 2009 04:42:32 schrieb Michael Mossey:
I'm working on a GUI application in qtHaskell, and I have a bit of a bind.
Using ghci, it launches quickly but runs slowly. On the other hand,
compiling (mainly linking) takes a while---several minutes. The truth is
Is the library
On Sep 17, 2009, at 20:17 , xu zhang wrote:
case op of
And - let a = 4
Or - let a = 3
Implies - let a = 2
Equiv - let a = 1
let isn't an assignment command, it's a scoping command. That is,
let a = 3 in ...
is equivalent to something like
{
Hello Michael,
Friday, September 18, 2009, 6:42:32 AM, you wrote:
Now I'm wondering if Hugs is a faster interpreter.
2x slower, and incompatib;e with qtHaskell
meaningful way without compilation. Any advice welcome. Maybe there is a
way to speed up the interpretation.
if compilation is
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