OK I'll include the module after I change the things mentioned.
BTW, I finally have an initial version of the parameterized-data package:
Darcs repository:
http://code.haskell.org/parameterized-data
Haddock documentation:
http://code.haskell.org/~fons/parameterized-data/doc/
Any
(I'm copying the list on this, since my reply contains a tutorial
which might be of use to other beginners.)
On 19/02/2008, Alan Carter [EMAIL PROTECTED] wrote:
Hi Cale,
On Feb 19, 2008 3:48 PM, Cale Gibbard [EMAIL PROTECTED] wrote:
Just checking up, since you haven't replied on the list.
Am Mittwoch, 20. Februar 2008 09:20 schrieben Sie:
OK I'll include the module after I change the things mentioned.
BTW, I finally have an initial version of the parameterized-data package:
Darcs repository:
http://code.haskell.org/parameterized-data
Haddock documentation:
Now, to help solve this problem, I wrote ListLike[2], providing a
set of typeclasses that make list operations generic. I also provided
default instances of ListLike for:
ListLike Data.ByteString.ByteString Word8
ListLike Data.ByteString.Lazy.ByteString Word8
ListLike [a] a
(Integral i,
Hi folks,
Before I started using Haskell, I used OCaml for a spell. One of my
biggest annoyances with OCaml was that it had two list types: the
default list (strict), and a lazy list (known as a stream).
This led to all sorts of annoyances. Libraries were always written to
work with one list
On Wed, Feb 20, 2008 at 08:39:13AM -0600, John Goerzen wrote:
I am concerned that the same thing is happening in Haskell. We now
have three common list-like types: the regular list, strict
ByteString, and lazy ByteString.
This has created some annoying situations. For instance, a
2008/2/19 Jeff φ [EMAIL PROTECTED]:
instance SmartArraySelector UArray Bool where
instance SmartArraySelector UArray Char where
instance SmartArraySelector UArray Double where
instance SmartArraySelector UArray Float where
instance SmartArraySelector UArray Intwhere
Well, I'm not
Call for Papers
Seventh International Conference on
Generative Programming and Component Engineering (GPCE 2008)
October 19-23, 2008
Nashville, Tennessee
On Wed, 20 Feb 2008, Brent Yorgey wrote:
2008/2/19 Jeff ö [EMAIL PROTECTED]:
instance SmartArraySelector UArray Bool where
instance SmartArraySelector UArray Char where
instance SmartArraySelector UArray Double where
instance SmartArraySelector UArray Float where
instance
On 2008-02-20, Ross Paterson [EMAIL PROTECTED] wrote:
conventions won't be usable in my ByteString code, for instance.
[...]
http://software.complete.org/listlike/static/doc/ListLike/Data-ListLike.html
As Henning pointed out, multiple parameter type classes are problematic
for core
On 2008-02-20, John Goerzen [EMAIL PROTECTED] wrote:
I notice that Data.Foldable does some similar things but does not use
multi-parameter type classes. I seem to recall that I attempted to do
this in the same manner, but got tripped up somewhere. I can't
remember now exactly what the
Hi
full - Maybe (item, full)
Hrm, what exactly is the return data here? Is is the head and the
tail if the list has = 1 item, or Nothing otherwise? Or...?
Yes, its the projection onto another type:
[] = Nothing
(x:xs) = Just (x, xs)
What is the problem with MPTC in base?
Hello everyone,
I am trying to create an AST for Python. My approach is to create a
data type for each syntactic construct. But I am stuck trying to
statically enforce some constraints over my statements. A very short
example to illustrate my problem:
newtype Ident = Id String
data BinOp = Add
On Wed, Feb 20, 2008 at 11:26 AM, Wolfgang Jeltsch
[EMAIL PROTECTED] wrote:
Hello Fons,
why do you use the term vector? I'd say that this term is more or less wrong
for what this type is about. The distinguishing property of vectors compared
to lists is that there is addition and scalar
Hi
Something like this would do?
if_ = Compound $ If [(IntLit 6, Suite [] [Break])] Nothing
while_ = Compound $ While (IntLit 6) (Suite [] [if_]) Nothing
f = Program [while_]
-- this one fails
-- f2 = Program [if_]
newtype Ident = Id String
data BinOp = Add
| Sub
data Exp =
John Goerzen wrote:
On 2008-02-20, John Goerzen [EMAIL PROTECTED] wrote:
I notice that Data.Foldable does some similar things but does not use
multi-parameter type classes. I seem to recall that I attempted to do
this in the same manner, but got tripped up somewhere. I can't
remember now
On Feb 17, 2008 6:06 PM, Derek Elkins [EMAIL PROTECTED] wrote:
It's -quite- possible that a coalgebraic perspective is much more
natural for your code/problem. If that's the case, use it (the
coalgebraic perspective that is). Obviously depending on the internals
of the stream library is not
Henning Thielemann lemming at henning-thielemann.de writes:
4) We are missing one final useful type: a Word32-based ByteString.
When working in the Unicode character set, a 32-bit character
can indeed be useful, and I could see situations in which the
performance benefit of a
On Feb 20, 2008 12:48 PM, Chad Scherrer [EMAIL PROTECTED] wrote:
StorableVector should fill this gap.
http://code.haskell.org/~sjanssen/storablevector/
Yes, it could, but
(1) it's way behind ByteString in terms of optimizations (== fusion)
(2) there's (as far as I know) not a
On Feb 20, 2008 10:57 AM, Antoine Latter [EMAIL PROTECTED] wrote:
For anyone looking into it - the StorableVector fusion would have to
be quite different from the current ByteString fusion framework.
Maybe it would be enough to lay down a Stream fusion framework for
StorableVectors.
I must be
On 2008-02-20, Jules Bean [EMAIL PROTECTED] wrote:
Not directly, no.
The point about Foldable, Functor, and Monad, is that they enforce the
connection between container and contents. If the contents is of type
a, the container is of type f a for a fixed type constructor 'f'.
This works
On Feb 20, 2008 12:59 PM, Chad Scherrer [EMAIL PROTECTED] wrote:
On Feb 20, 2008 10:57 AM, Antoine Latter [EMAIL PROTECTED] wrote:
For anyone looking into it - the StorableVector fusion would have to
be quite different from the current ByteString fusion framework.
Maybe it would be enough
Cale,
On Feb 20, 2008 10:58 AM, Cale Gibbard [EMAIL PROTECTED] wrote:
(I'm copying the list on this, since my reply contains a tutorial
which might be of use to other beginners.)
Thank you so much for this - I've just started playing with it so few
intelligent responses yet. I'm sure it will
I'm getting errors when I click on any of the links. I'm not sure who
administers the site.
IOError Python 2.4.4: /usr/bin/python
Wed Feb 20 11:41:13 2008
A problem occurred in a Python script. Here is the sequence of function
calls leading up to the error, in the order they occurred.
Antoine Latter [EMAIL PROTECTED] wrote:
From what I saw of Data.ByteString.Fusion, it relies on the assumption
that the elements of the output array are of the same size and
alignment as the elements of all of the arrays in the fused
intermediate steps. That way, all of the intermediate
Wolfgang Jeltsch wrote:
I’m also in the process of shortening the names for type variables since
in conference papers you cannot use names that long (because otherwise you
quickly overrun the available width) and I don’t want to have too many
differences between papers and actual source code.
-- proposition
data Prp a = Var a
| Not (Prp a)
| Or (Prp a) (Prp a)
| And (Prp a) (Prp a)
| Imp (Prp a) (Prp a)
| Xor (Prp a) (Prp a)
| Eqv (Prp a) (Prp a)
| Cns Bool
deriving (Show, Eq)
-- Here are to
Wolfgang Jeltsch wrote:
Am Montag, 18. Februar 2008 19:46 schrieb Carlos Gomez A.:
hi, my name is carlos
I need information for correct installor
what are dependencies on ghc ?
I have a Debian System.
Always use your distribution’s packages until they aren’t any or there is
good
joseph.bruce:
Hi,
I have a Haskell library that I want to make available via FFI to C
programmers on my project team. I read this thread
(http://thread.gmane.org/gmane.comp.lang.haskell.cafe/21447) which had
some interesting ideas, but they seemed unresolved. Or maybe it answers
my
I proudly announce a little toy that lists the frequency of modules
being imported by other modules. Do you know Control.Monad is the most
frequently imported module? I did not!
Currently it only includes GHC 6.8 core library. If you have any idea
how to parse through HackageDB code, please let
On Wed, Feb 20, 2008 at 07:28:54PM +, Dominic Steinitz wrote:
I'm getting errors when I click on any of the links.
I've created /tmp/darcsweb-cache and made it writable, which seems to
have made it work again.
I'm not sure who administers the site.
Neither am I, but it needs some tweaking
Jeff φ wrote:
However, my implementation of SmartArray requires me to create an instance
of a selector class to tell the compiler whether the type is boxed or
unboxed. I'm hoping to avoid creating instances of the selector class for
every possible type. I'd be grateful for any suggestions.
All,
Apologies for multiple listings.
This is just a friendly reminder that a small cadre of us are organizing a
Northwest Functional Programming Interest Group. Our first official meeting
is today at the
The Seattle Public Library
1000 - 4th Ave.
Seattle, WA 98104
Spiral 6 Conference Room
John Goerzen wrote:
On 2008-02-20, Jules Bean [EMAIL PROTECTED] wrote:
Not directly, no.
The point about Foldable, Functor, and Monad, is that they enforce the
connection between container and contents. If the contents is of type
a, the container is of type f a for a fixed type constructor
On Wed, Feb 20, 2008 at 11:18:51PM +0100, Ben Franksen wrote:
John Goerzen wrote:
On 2008-02-20, Jules Bean [EMAIL PROTECTED] wrote:
Not directly, no.
The point about Foldable, Functor, and Monad, is that they enforce the
connection between container and contents. If the contents is
David Roundy wrote:
On Wed, Feb 20, 2008 at 11:18:51PM +0100, Ben Franksen wrote:
John Goerzen wrote:
On 2008-02-20, Jules Bean [EMAIL PROTECTED] wrote:
Not directly, no.
The point about Foldable, Functor, and Monad, is that they enforce the
connection between container and contents.
On 2008-02-20, John Goerzen [EMAIL PROTECTED] wrote:
On the other hand, if you mean using a dictionary to wrap just the
ByteString types (or other similar ones), I am currently thinking of
something along those lines. I'll post here if I come up with
something clever (or not).
Can't come up
On Wed, 2008-02-20 at 08:39 -0600, John Goerzen wrote:
* The iconv library works only on lazy ByteStrings, and does not
handle Strings or strict ByteStrings
There is a very good reason for this. The right solution in this
particular example is not to overload every internal string
Hello John,
Tuesday, February 12, 2008, 9:28:22 PM, you wrote:
I was recently looking at the STM library, and I have a question about
the function unsafeIOToSTM. Can anyone explain to me what is unsafe
about it, and what sort of use would be considered safe?
STM operations can be repeated if
Hello Alfonso,
Tuesday, February 12, 2008, 11:32:20 PM, you wrote:
Excuse me for the subject, but IMHO is absolutely true. Anyhow, the
of course, you are right, but for practical goals i may suggest just
to read module sources instead of reading [had]docs. seeing the
implementation is much
Am Mittwoch, 20. Februar 2008 22:22 schrieb Steve Lihn:
I proudly announce a little toy that lists the frequency of modules
being imported by other modules. Do you know Control.Monad is the most
frequently imported module? I did not!
This doesn’t surprise me very much. What surprises me more
On Wed, Feb 20, 2008 at 09:22:58PM +, Steve Lihn wrote:
I proudly announce a little toy that lists the frequency of modules
being imported by other modules. Do you know Control.Monad is the most
frequently imported module? I did not!
Currently it only includes GHC 6.8 core library. If
If ~ does not have any special meaning and it could be ### or xyz,
then how does GHC know to print
a ~ b, but not ~ a b
a ### b, but not ### a b
xyz a b, but not a `xyz` b
Simply because xyz is alphanumeric?
On Wed, Feb 20, 2008 at 12:34 AM, David Menendez [EMAIL PROTECTED] wrote:
On Feb
On Wed, Feb 20, 2008 at 07:18:42PM -0500, Steve Lihn wrote:
If ~ does not have any special meaning and it could be ### or xyz,
then how does GHC know to print
a ~ b, but not ~ a b
a ### b, but not ### a b
xyz a b, but not a `xyz` b
Simply because xyz is alphanumeric?
Yes.
Stefan
On Wed, Feb 20, 2008 at 10:17 PM, Bulat Ziganshin
[EMAIL PROTECTED] wrote:
Hello Alfonso,
Tuesday, February 12, 2008, 11:32:20 PM, you wrote:
Excuse me for the subject, but IMHO is absolutely true. Anyhow, the
of course, you are right, but for practical goals i may suggest just
to
There was a chat today on
#haskellhttp://tunes.org/%7Enef/logs/haskell/08.02.20
(15:08 to 16:10) about evolving haddock. I'd like to get comments.
The goal is to get the full functionality of a general purpose,
programmer-friendly markup language like markdown. One example is image
embedding.
Stefan O'Rear wrote:
On Wed, Feb 20, 2008 at 07:18:42PM -0500, Steve Lihn wrote:
If ~ does not have any special meaning and it could be ### or xyz,
then how does GHC know to print
a ~ b, but not ~ a b
a ### b, but not ### a b
xyz a b, but not a `xyz` b
Simply because xyz is
On Wednesday 20 February 2008 5:13:34 pm Duncan Coutts wrote:
On Wed, 2008-02-20 at 08:39 -0600, John Goerzen wrote:
* The iconv library works only on lazy ByteStrings, and does not
handle Strings or strict ByteStrings
There is a very good reason for this. The right solution in this
Oleg's done a lot of work here; there's a bunch of magic that can be
done with TypeCast. I took my inspiration from here:
http://okmij.org/ftp/Haskell/typecast.html#ambiguity-resolution
Here are some tests in ghci (note that I specialized the index type in
test to Int to make this shorter; doing
Chad Scherrer wrote:
Here's an example of the problem. Start with a function
extract :: [Int] - [a] - [a]
extract = f 0
where
f !k nss@(n:ns) (x:xs)
| n == k= x : f (k+1) ns xs
| otherwise = f (k+1) nss xs
f _ _ _ = []
If you want this to play nicely with stream
On 2/20/08, Bulat Ziganshin [EMAIL PROTECTED] wrote:
STM operations can be repeated if first transaction was unsuccessful.
so, you may se here only operations that may be safely repeated - say,
reading/writing memory areas, or reading/writing files, or even
sending network message as long as
John Goerzen wrote:
I am concerned that the same thing is happening in Haskell. We know
have three common list-like types: the regular list, strict
ByteString, and lazy ByteString.
Why do you consider ByteString to be list-like but not arrays?
1) Does everyone agree with me that we have a
It depends what you mean by faster; more efficient (runtime) or less
typing (programmer time!)
For the former, you have basically the best implementation there is;
you are basically encoding the continuation of (++) into the
accumulating list of arguments to evs. You might want to consider
Rewriting that script in Haskell could be an
interesting exercise. Do you have the source code?
Benjamin L. Russell
--- Steve Lihn [EMAIL PROTECTED] wrote:
I proudly announce a little toy that lists the
frequency of modules
being imported by other modules. Do you know
Control.Monad is the
G'day all.
Quoting Cetin Sert [EMAIL PROTECTED]:
-- proposition
data Prp a = Var a
| Not (Prp a)
| Or (Prp a) (Prp a)
| And (Prp a) (Prp a)
| Imp (Prp a) (Prp a)
| Xor (Prp a) (Prp a)
| Eqv (Prp a) (Prp a)
| Cns Bool
G'day all.
Quoting Neil Mitchell [EMAIL PROTECTED]:
Yes, its the projection onto another type:
[] = Nothing
(x:xs) = Just (x, xs)
Also known as msplit:
http://www.haskell.org/haskellwiki/New_monads/MonadSplit
Cheers,
Andrew Bromage
___
On Wed, 20 Feb 2008, Chad Scherrer wrote:
On Feb 20, 2008 10:57 AM, Antoine Latter [EMAIL PROTECTED] wrote:
For anyone looking into it - the StorableVector fusion would have to
be quite different from the current ByteString fusion framework.
Maybe it would be enough to lay down a Stream
On Thu, 21 Feb 2008, Roman Leshchinskiy wrote:
John Goerzen wrote:
2) Would it make sense to make ListLike, or something like it,
part of the Haskell core?
I don't think ListLike is the right approach. It's basically a fairly
arbitrary collection of functions. It would be preferable,
plong 0 = Var 0
plong n | even n= Or (Var n) (plong (n-1))
| otherwise = And (Var n) (plong (n-1))
main = do print ((length ∘ vars) (plong 1000))
real0m3.290s
user0m3.152s
sys 0m0.020s
main = do print ((length ∘ vars_) (plong 1000))
real0m3.732s
user
I take it that this follows from the lack of any mechanism to rollback
IO? If so, I think that the following guidelines suffice for when
it's acceptable to use unsafeIOtoSTM:
1. The IO action must be able to be safely repeated.
2. The IO action must be able to be safely performed with
On Thu, 21 Feb 2008, Wolfgang Jeltsch wrote:
Am Mittwoch, 20. Februar 2008 22:22 schrieb Steve Lihn:
I proudly announce a little toy that lists the frequency of modules
being imported by other modules. Do you know Control.Monad is the most
frequently imported module? I did not!
This
On Thu, 2008-02-21 at 05:10 +0100, Cetin Sert wrote:
plong 0 = Var 0
plong n | even n= Or (Var n) (plong (n-1))
| otherwise = And (Var n) (plong (n-1))
compare the times again but with plong as follows:
plong 0 = Var 0
plong n | even n = Or (plong (n-1)) (Var n)
|
On Wednesday 20 February 2008 8:42:56 pm Roman Leshchinskiy wrote:
John Goerzen wrote:
I am concerned that the same thing is happening in Haskell. We know
have three common list-like types: the regular list, strict
ByteString, and lazy ByteString.
Why do you consider ByteString to be
G'day all.
Quoting Cetin Sert [EMAIL PROTECTED]:
It is astonishing to see that your version actually performs the worst (at
least on my machine).
On your example, I'm not surprised:
plong 0 = Var 0
plong n | even n= Or (Var n) (plong (n-1))
| otherwise = And (Var n) (plong
[EMAIL PROTECTED]:~/workspace/Haskell-1/bin$ time ./theResult sert
101
real0m1.384s
user0m1.148s
sys 0m0.112s
[EMAIL PROTECTED]:~/workspace/Haskell-1/bin$ time ./theResult bromage
101
real0m2.240s
user0m1.972s
sys 0m0.176s
[EMAIL
I would expect my (well, I didn't invent it) to work better on something
that didn't have this unique structure, such as:
test 0 = Var 0
test n | even n= Or (Var n) (test (n-1))
| otherwise = And (test (n-1)) (Var n)
for some reason this still does not perform as well as it should
On 2/19/08, Ryan Ingram [EMAIL PROTECTED] wrote:
Oleg's done a lot of work here; there's a bunch of magic that can be
done with TypeCast. I took my inspiration from here:
http://okmij.org/ftp/Haskell/typecast.html#ambiguity-resolution
. . .
The trick is to represent whether a type is
On Wed, Feb 20, 2008 at 10:46 PM, [EMAIL PROTECTED] wrote:
Quoting Neil Mitchell [EMAIL PROTECTED]:
Yes, its the projection onto another type:
[] = Nothing
(x:xs) = Just (x, xs)
Also known as msplit:
http://www.haskell.org/haskellwiki/New_monads/MonadSplit
Almost. The
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