Jonathan Cast [EMAIL PROTECTED] wrote:
On 4 Jan 2008, at 2:00 AM, Nicholls, Mark wrote:
You may be right...but learning is not an atomic thingwherever I
start I will get strange things happening.
The best place to start learning Haskell is with the simplest type
features, not the
Don Stewart wrote:
---
Haskell Weekly News
Issue 68 - January 05, 2008
---
Announcements
GHC 6.8.2. The GHC Team [2]announced the release of GHC
Galchin Vasili wrote:
Hello,
https://buildsecurityin.us-cert.gov/daisy/bsi/articles/knowledge/coding/295.html
I stumbled across this page. It seems that Haskell and other strongly
typed functional languages like Ml/OCaml will fare much, much better,
e.g. buffer overrun. Thoughts .
Just a couple of things I was wondering about...
1. Is there some way to assign a priority to Haskell threads? (The
behaviour I'd like is that high priority threads always run first, and
low priority threads potentially never run at all unless there's an
available processor which is
I've searched all over the place, and I can't find this information
actually announced anywhere except on the GHC homepage itself. And
yet, I've seen emails bouncing around that appear to be replies to the
announcement email. But I can't find the actual announcement email
anywhere. Am I
Allan Clark wrote:
I've searched all over the place, and I can't find this information
actually announced anywhere except on the GHC homepage itself. And
yet, I've seen emails bouncing around that appear to be replies to
the announcement email. But I can't find the actual announcement
On Jan 6, 2008 9:30 AM, Andrew Coppin [EMAIL PROTECTED] wrote:
2. I have a situation where I have a thread generating some data and
putting it into a mutable array, and another thread trying to read that
data. Is there a way I can make the reader thread block if it tries to
read a cell that
Andrew Coppin [EMAIL PROTECTED] wrote:
2. I have a situation where I have a thread generating some data and
putting it into a mutable array, and another thread trying to read
that data. Is there a way I can make the reader thread block if it
tries to read a cell that hasn't been computed
Felipe Lessa wrote:
On Jan 6, 2008 9:30 AM, Andrew Coppin [EMAIL PROTECTED] wrote:
2. I have a situation where I have a thread generating some data and
putting it into a mutable array, and another thread trying to read that
data. Is there a way I can make the reader thread block if it tries
I wrote:
What goes wrong with finite coproducts? The obvious thing to
do would be to take the disjoint union of the sets representing the
types, identifying the copies of _|_.
Jonathan Cast wrote:
This isn't a coproduct. If we have f x = 1 and g y = 2, then there
should exist a function h
On Fri, 2007-12-28 at 17:54 -0600, Jonathan Cast wrote:
Programming languages are generally classified into three groups,
imperative, functional, and logical. The difference is in the style
of programming encouraged (or mandated, for older languages) by the
language.
Usually the
On Sun, 2007-12-30 at 12:27 +0100, [EMAIL PROTECTED]
wrote:
[...]
I don't understand your point. We know what swimming is: floating and
moving autonomously. Thinking is different, since our thinking is (at least
for some of us) conscious, and we have no idea what is the conscience.
For
On Wed, 2008-01-02 at 15:49 +0200, Yitzchak Gale wrote:
[...]
Some people are worried that this version of Hask is missing
certain nice properties that one would like to have. For
example, it was recently claimed on this list that tuples
are not products in that category. (Or some such. I
(sorry, I hit the send button)
What is the lifted version you are referring to?
Take the ordinary disjoint union, and then add a new _|_ element,
distinct from both existing copies of _|_ (which are still distinct
from each other).
Now why is that not the category-theoretic coproduct?
h .
Hi,
Andrew Coppin wrote:
Galchin Vasili wrote:
Hello,
https://buildsecurityin.us-cert.gov/daisy/bsi/articles/knowledge/coding/295.html
I stumbled across this page. It seems that Haskell and other strongly
typed functional languages like Ml/OCaml will fare much, much better,
Am Sonntag, 6. Januar 2008 14:27 schrieb Mads Lindstrøm:
Hi,
Andrew Coppin wrote:
Galchin Vasili wrote:
Hello,
https://buildsecurityin.us-cert.gov/daisy/bsi/articles/knowledge/coding
/295.html
I stumbled across this page. It seems that Haskell and other strongly
typed
Mads Lindstrøm wrote:
Hi,
Andrew Coppin wrote:
Human kind has yet to design a programming language which eliminates all
possible bugs. ;-)
And we never will.
Quite so. How can a machine possibly tell whether a given behaviour is a
bug or an intended behaviour? This is impossible.
Daniel Fischer wrote:
Just because I don't know:
what bugs would be possible in a language having only the instruction
return ()
Bug #1: You cannot write any nontrivial programs. ;-)
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
Daniel Fischer [EMAIL PROTECTED] wrote:
Just because I don't know:
what bugs would be possible in a language having only the instruction
return ()
(';' for imperative programmers)?
/me waves meaningful with his hand.
--
(c) this sig last receiving data processing entity. Inspect headers
I wrote:
...it was recently claimed on this list that tuples
are not products in that category.
Derek Elkins wrote:
Johnathan has given such a demonstration (and it has been demonstrated
many times on this list since it's creation, it's well-known).
We're still working on it. I've not been
Mads Lindstrøm wrote:
Andrew Coppin wrote:
Human kind has yet to design a programming language which eliminates all
possible bugs. ;-)
And we never will. See http://en.wikipedia.org/wiki/Halting_problem .
If you limit usage of general recursion (and rather favor structural
recursion) then
Am Sonntag, 6. Januar 2008 15:18 schrieb Andrew Coppin:
Daniel Fischer wrote:
Just because I don't know:
what bugs would be possible in a language having only the instruction
return ()
Bug #1: You cannot write any nontrivial programs. ;-)
That's not a bug, that's a feature.
Daniel Fischer [EMAIL PROTECTED] wrote:
Am Sonntag, 6. Januar 2008 15:18 schrieb Andrew Coppin:
Daniel Fischer wrote:
Just because I don't know:
what bugs would be possible in a language having only the
instruction return ()
Bug #1: You cannot write any nontrivial programs. ;-)
Peter Hercek writes:
Andrew Coppin wrote:
Human kind has yet to design a programming language which eliminates all
possible bugs. ;-)
...you can mitigate the halting problem.
But there always will be specification bugs (when one implenetes something
else than what was needed).
Look, you
Achim Schneider wrote:
That's an interesting task: Design a non-touring complete,
restricted language in which every expression is decidable, without
making the language unusable for usual programming problems.
Have a look about dependently typed languages like Epigram:
Am Sonntag, 6. Januar 2008 15:54 schrieb Achim Schneider:
Daniel Fischer [EMAIL PROTECTED] wrote:
Am Sonntag, 6. Januar 2008 15:18 schrieb Andrew Coppin:
Daniel Fischer wrote:
Just because I don't know:
what bugs would be possible in a language having only the
instruction return
On Sun, 06 Jan 2008 17:19:31 +0200, Daniel Fischer
[EMAIL PROTECTED] wrote:
Am Sonntag, 6. Januar 2008 15:54 schrieb Achim Schneider:
Daniel Fischer [EMAIL PROTECTED] wrote:
Am Sonntag, 6. Januar 2008 15:18 schrieb Andrew Coppin:
Daniel Fischer wrote:
Just because I don't know:
what
Yitzchak Gale wrote:
I wrote:
...it was recently claimed on this list that tuples
are not products in that category.
I've not been convinced yet.
I'm going to try convince you :) The crucial problem of Haskell's
product is that (_|_,_|_) ≠ _|_ but that the two projections
fst :: (A,B)
On Sun, 2008-01-06 at 16:19 +0100, Daniel Fischer wrote:
Am Sonntag, 6. Januar 2008 15:54 schrieb Achim Schneider:
Daniel Fischer [EMAIL PROTECTED] wrote:
Am Sonntag, 6. Januar 2008 15:18 schrieb Andrew Coppin:
Daniel Fischer wrote:
Just because I don't know:
what bugs would be
On 2008.01.06 15:54:00 +0100, Achim Schneider [EMAIL PROTECTED] scribbled
0.6K characters:
Daniel Fischer [EMAIL PROTECTED] wrote:
Am Sonntag, 6. Januar 2008 15:18 schrieb Andrew Coppin:
Daniel Fischer wrote:
Just because I don't know:
what bugs would be possible in a language
Take the ordinary disjoint union, and then add a new _|_ element,
distinct from both existing copies of _|_ (which are still distinct
from each other).
Now why is that not the category-theoretic coproduct?
h . Left = f and h . Right = g both for _|_ and for finite
elements of the types. And it
On 6 Jan 2008, at 3:02 AM, Derek Elkins wrote:
On Fri, 2007-12-28 at 17:54 -0600, Jonathan Cast wrote:
Programming languages are generally classified into three groups,
imperative, functional, and logical. The difference is in the style
of programming encouraged (or mandated, for older
On 6 Jan 2008, at 2:13 AM, Achim Schneider wrote:
Jonathan Cast [EMAIL PROTECTED] wrote:
On 4 Jan 2008, at 2:00 AM, Nicholls, Mark wrote:
You may be right...but learning is not an atomic thingwherever I
start I will get strange things happening.
The best place to start learning
On 6 Jan 2008, at 3:55 AM, Yitzchak Gale wrote:
I wrote:
What goes wrong with finite coproducts? The obvious thing to
do would be to take the disjoint union of the sets representing the
types, identifying the copies of _|_.
Jonathan Cast wrote:
This isn't a coproduct. If we have f x = 1
On 6 Jan 2008, at 5:32 AM, Yitzchak Gale wrote:
(sorry, I hit the send button)
What is the lifted version you are referring to?
Take the ordinary disjoint union, and then add a new _|_ element,
distinct from both existing copies of _|_ (which are still distinct
from each other).
Now why
Hi,
I am new to functional and lazy programming languages ( that's correct, my
life has been pretty pathetic so far) and am not able to understand GHC's
behaviour for a particular function. Can someone help me please?
I am trying to write a function which would compare two strings (from
reverse)
You have used the name 'pos' twice, for both the parameter and the
returned value of the recursive call. The reason this results in an
infinite loop is that in code like
let x = x + 1
Haskell treats both xs to be references to the same thing, so evaluates:
x
= x + 1
= (x + 1) + 1
= ((x + 1) + 1)
On 6 Jan 2008, at 10:34 AM, Sai Hemanth K wrote:
Hi,
I am new to functional and lazy programming languages ( that's
correct, my life has been pretty pathetic so far) and am not able
to understand GHC's behaviour for a particular function. Can
someone help me please?
I am trying to
On Jan 6, 2008 4:40 PM, Jonathan Cast [EMAIL PROTECTED] wrote:
let is always recursive in Haskell, so this is a recursive definition
of pos. To break the recursion, use
matchReverse (x:xs) (y:ys) pos = let (matched, pos') = matchReverse
xs ys (pos + 1)
in
AAh! Thanks a ton!
Hemanth K
On Jan 7, 2008 12:10 AM, Rodrigo Queiro [EMAIL PROTECTED] wrote:
You have used the name 'pos' twice, for both the parameter and the
returned value of the recursive call. The reason this results in an
infinite loop is that in code like
let x = x + 1
Haskell
Jonathan Cast [EMAIL PROTECTED] wrote:
On 6 Jan 2008, at 2:13 AM, Achim Schneider wrote:
Jonathan Cast [EMAIL PROTECTED] wrote:
On 4 Jan 2008, at 2:00 AM, Nicholls, Mark wrote:
You may be right...but learning is not an atomic
thingwherever I start I will get strange things
That's an interesting task: Design a non-touring complete,
restricted language in which every expression is decidable, without
making the language unusable for usual programming problems.
Well, I did something like that a few years ago - it was a sort of
assembler language, allowing the
Felipe Lessa wrote:
As as side note, GHC's flag -Wall would have warned about creating a
variable with a name already in scope.
*makes a mental note*
I've created bugs like this far too many times...
___
Haskell-Cafe mailing list
Derek Elkins [EMAIL PROTECTED] writes:
I don't understand your point. We know what swimming is: floating and
moving autonomously.
You're the first one I've heard who would use the term 'swimming' for
ships. (And to be pedantic, wouldn't you say that fish swim, except
when they float?)
The
Jonathan Cast jonathanccast at fastmail.fm writes:
Extensionality is a key part of the definition of all of these
constructions. The categorical rules are designed to require, in
concrete categories, that the range of the two injections into a
coproduct form a partition of the
On Jan 6, 2008, at 15:02 , Ketil Malde wrote:
More seriously, perhaps quantum enters into the equation in how the
brain works, perhaps it is even necessary for thought. However, I
get worried it's just another mystical mantra, a gratuitous factor
that, lacking any theory about how and what it
Miguel Mitrofanov wrote:
That's an interesting task: Design a non-touring complete,
restricted language in which every expression is decidable, without
making the language unusable for usual programming problems.
Well, I did something like that a few years ago - it was a sort of
assembler
On 6 Jan 2008, at 12:27 PM, Dominic Steinitz wrote:
Jonathan Cast jonathanccast at fastmail.fm writes:
Extensionality is a key part of the definition of all of these
constructions. The categorical rules are designed to require, in
concrete categories, that the range of the two injections
Andrew Coppin wrote:
Felipe Lessa wrote:
On Jan 6, 2008 9:30 AM, Andrew Coppin [EMAIL PROTECTED]
wrote:
2. I have a situation where I have a thread generating some data and
putting it into a mutable array, and another thread trying to read that
data. Is there a way I can make the reader
On Sun, 2008-01-06 at 09:45 -0800, Jonathan Cast wrote:
On 6 Jan 2008, at 3:02 AM, Derek Elkins wrote:
On Fri, 2007-12-28 at 17:54 -0600, Jonathan Cast wrote:
Programming languages are generally classified into three groups,
imperative, functional, and logical. The difference is in the
Derek Elkins writes:
Jonathan Cast wrote:
I find the term `declarative' to be almost completely meaningless.
I was originally thinking of having the final sentence: There are no
clear, accepted meanings for any of these terms.
Clear, no.
Accepted, yes.
Let Jonathan Cast repeat that
Brandon S. Allbery KF8NH wrote:
On Jan 6, 2008, at 15:02 , Ketil Malde wrote:
More seriously, perhaps quantum enters into the equation in how the
brain works, perhaps it is even necessary for thought. However, I
get worried it's just another mystical mantra, a gratuitous factor
that, lacking
On Sun, 2008-01-06 at 22:31 +0100, [EMAIL PROTECTED]
wrote:
Derek Elkins writes:
Jonathan Cast wrote:
I find the term `declarative' to be almost completely meaningless.
I was originally thinking of having the final sentence: There are no
clear, accepted meanings for any of these
On 6 Jan 2008, at 1:31 PM, [EMAIL PROTECTED] wrote:
Derek Elkins writes:
Jonathan Cast wrote:
I find the term `declarative' to be almost completely meaningless.
I was originally thinking of having the final sentence: There are no
clear, accepted meanings for any of these terms.
Clear, no.
On 6 Jan 2008, at 12:13 PM, Derek Elkins wrote:
On Sun, 2008-01-06 at 09:45 -0800, Jonathan Cast wrote:
On 6 Jan 2008, at 3:02 AM, Derek Elkins wrote:
On Fri, 2007-12-28 at 17:54 -0600, Jonathan Cast wrote:
Programming languages are generally classified into three groups,
imperative,
ChrisK [EMAIL PROTECTED] wrote:
how the brain works appears to be though electro- and bio-
chemistry, which are best modeled/described right now by quantum
mechanics.
Erm...
There is this story about some military (US afair) training a neural
net to detect tanks in images, I can't find the
On Sun, 2008-01-06 at 13:48 -0800, Jonathan Cast wrote:
On 6 Jan 2008, at 1:31 PM, [EMAIL PROTECTED] wrote:
Derek Elkins writes:
Jonathan Cast wrote:
I find the term `declarative' to be almost completely meaningless.
I was originally thinking of having the final sentence: There are no
Derek Elkins writes:
Jonathan Cast wrote:
I find the only
similarity between Haskell and Prolog to be that neither is imperative.
Indeed, you've discovered it. The definition of declarative is often
not imperative.
I disagree. Practically. (I won't discuss doctrinal matter nor
If I understand it correctly, implicit parameters in Haskell allow you to
pass values to functions with explicitly adding a parameter to each of the
functions being called (I appologize for my imperative terminology here.
How would I say this correctly? Being evaluated?)
The arrows always use
Jerzy wrote:
The relational syntax of Prolog is more universal than the functional
notation, since you have logic variables and logical-non-determinism, and
Isn't this just because mathematically, a function *is* a relation, but not
vice versa? A relation being just a subset of a Cartesian
I recently tried the latest version of HS-PLUGINS, and it gave an error on
Windows. After a bit of Googling it seemed Conal Elliot had the same
problem. I reported this problem to the author. This is also (one of) the
reason why I could not get YI running on Windows.
Now, according to the
Peter Verswyvelen writes:
Jerzy wrote:
The relational syntax of Prolog is more universal than the functional
notation, since you have logic variables and logical-non-determinism, and
Isn't this just because mathematically, a function *is* a relation, but not
vice versa? A relation being
On Sun, 2008-01-06 at 23:28 +0100, [EMAIL PROTECTED]
wrote:
Derek Elkins writes:
Jonathan Cast wrote:
I find the only
similarity between Haskell and Prolog to be that neither is imperative.
Indeed, you've discovered it. The definition of declarative is often
not imperative.
On Sun, 2008-01-06 at 23:44 +0100, Peter Verswyvelen wrote:
If I understand it correctly, implicit parameters in Haskell allow you
to pass values to functions with explicitly adding a parameter to each
of the functions being “called” (I appologize for my imperative
terminology here. How would
Over the Xmas break I made some headway on writing an RPC package
since many of the ideas that I want to play with involve such a thing
as a basic building block. However, some might find some of the
spin-off packages that I wrote along the way useful.
* binary-strict:
This is mostly a
On 2008-01-06, Jonathan Cast [EMAIL PROTECTED] wrote:
To wit, I do not believe the term `declarative' has any single
referent, even in the sense that the term `functional' has any single
referent. I find the only similarity between Haskell and Prolog to be
that neither is imperative.
Have
On 2008-01-06, ChrisK [EMAIL PROTECTED] wrote:
Brandon S. Allbery KF8NH wrote:
On Jan 6, 2008, at 15:02 , Ketil Malde wrote:
More seriously, perhaps quantum enters into the equation in how the
brain works, perhaps it is even necessary for thought. However, I
get worried it's just another
On 6 Jan 2008, at 4:00 PM, Aaron Denney wrote:
On 2008-01-06, Jonathan Cast [EMAIL PROTECTED] wrote:
To wit, I do not believe the term `declarative' has any single
referent, even in the sense that the term `functional' has any single
referent. I find the only similarity between Haskell and
On 2007.12.12 12:51:58 -0600, Tommy M McGuire [EMAIL PROTECTED] scribbled
2.7K characters:
Gwern Branwen wrote:
Some of those really look like they could be simpler, like 'copy' -
couldn't that simply be 'main = interact (id)'?
Have you seen http://haskell.org/haskellwiki/Simple_Unix_tools?
Just going back to this, the channel issue may be solved by the
strict-concurrency package (strict Chans and MVars), and the general
problem of distributing arrays seems to be solved more thoroughly
by the data parallel array library (map, fold, scanl, filter, zip et
al), not just map and reduce?
On Fri, 2007-12-28 at 09:51 -0700, Luke Palmer wrote:
On Dec 28, 2007 9:35 AM, Jules Bean [EMAIL PROTECTED] wrote:
In particular, adding sharing can stop something being GCed, which can
convert an algorithm which runs in linear time and constant space to one
which runs in linear space (and
Hi, all! I guess what I am about to ask is currently impossible, but as
you haskellers always manage to amaze me here it goes. Given two type
classes A t and B t, I'd like to derive (two) different A t instances
depending exactly on whether t is an instance of B. In other words, is it
possible
jgbailey:
I'm working on a project which would generate a PHP data-access layer
from a Haskell model. I'm wondering what libraries might be already be
available for generating PHP or other types of code. The
pretty-printing library is one option. Any other suggestions?
i only know of pretty
Adam Langley wrote:
This is mostly a cut-n-paste job from the excellent binary package
which provides Data.Binary.Strict.Get - a monad which is a drop in
replacement for Get, but which parses strict ByteStrings and returns
an Either,
Ooh, nice. We could really do with an incremental
Achim Schneider wrote:
There is this story about some military (US afair) training a neural
net to detect tanks in images, I can't find the link right now.
It worked, with amazing 100% accuracy.
Then they threw another batch of images at the net.
It worked, with devastating 50%
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