#4174: Jumbled error message from type family operator
-+--
Reporter: lilac | Owner:
Type: bug | Status: new
Hi,
I'm trying to create a data type for maps where both keys and values are
unpacked into the data type constructors (see code at the end of this
email). I achieve this using an associated data type of two arguments (`Map`
in the code below). The problem I have is that this definition requires
johan.tibell:
Hi,
I'm trying to create a data type for maps where both keys and values are
unpacked into the data type constructors (see code at the end of this email).
I
achieve this using an associated data type of two arguments (`Map` in the code
below). The problem I have is that this
(Apologies if you receive multiple copies of this announcement)
*
*** First Call for Participation ***
Third International Conference on Verified Software:
Theories, Tools, and Experiments
The Haskell 2010 report is done! I've uploaded it to www.haskell.org,
and linked it from the main Haskell wiki:
http://www.haskell.org/haskellwiki/Language_and_library_specification
online HTML version:
http://www.haskell.org/onlinereport/haskell2010
PDF:
1.2: it is essentially a slightly sugared variant of the lambda calculus
Should it be the simply-typed lambda calculus?
Also, there should be a reference; a significant percentage of those
reading this report will have never heard of the lambda calculus.
with a straightforward denotational
Does anybody know what are the analogous functions and data types in the
haskell library Sound.File.Sndfile of the libsndfile library in C ?
data type : SNDFILE
function: sf_open
function : sf_read_short
Thanks in advance,
--
Maria Gabriela Valdes G.
Linux Registered User #485743
Maria Gabriela Valdes wrote:
Does anybody know what are the analogous functions and data types in the
haskell library Sound.File.Sndfile of the libsndfile library in C ?
data type : SNDFILE
function: sf_open
function : sf_read_short
I have never used the Haskell bindings to that
http://www.haskell.org/~simonmar/haskell-2010-draft-report-2/haskellch3.html
infixexp → lexp qop infixexp (infix operator application)
| - infixexp(prefix negation)
| lexp
This grammar rule describes a right associative nesting of (any) infix
operators
On 16:01 Tue 29 Jun , Simon Marlow wrote:
Comments on the draft report are welcome, before I finalise this and
sign off on Haskell 2010.
Part II, The Haskell 2010 Libraries, appears to be completely missing
the Numeric module.
--
Nick Bowler, Elliptic Technologies
http://www.haskell.org/~simonmar/haskell-2010-draft-report-2/haskellch10.html#x17-17300010
Fixity resolution also applies to Haskell patterns, but patterns are a
subset of expressions so in what follows we consider only expressions
for simplicity.
The string 1 * - 1 is legal as pattern, but
Thanks! A lot of good ideas, although a GUI or database framework look like the most promising possibilities at the
moment. I like the email/wiki idea, although it may not meet the University's academic requirements. (Would probably
just be an email client running on top of a Wiki.) It may also
braver wrote:
I dump results of a computation as a Data.Trie of [(Int,Float)]. It
contains about 5 million entries, with the lists of 35 or less pairs
each. It takes 8 minutes to load with Data.Binary and lookup a single
key. What can take so long? If I change from compressed to
uncompressed
wren ng thornton w...@freegeek.org writes:
A bit more seriously: is there any listing anywhere of which extensions
Hugs supports?
Cabal has a partial listing embedded in its code, though I can't seem
to find a textual version at the moment. In general, Hugs has all the
features of GHC 6.6:
On Tuesday 06 July 2010 07:04:18, wren ng thornton wrote:
Cabal has a partial listing embedded in its code, though I can't seem to
find a textual version at the moment. In general, Hugs has all the
features of GHC 6.6: FFI, CPP, MPTCs, FunDeps, OverlappingInstances,...
I'm forgetting off-hand
Hi John,
As for the academic requirements, try formulating a question which is
answered by the program you write, for instance:
Is it possible to write an efficient [YOUR PROJECT] in a purely
functional setting?
Can the advantages of [PORTED UTILITY] be utilized without relying on
code with
One thing that would be nice is a unification of the general database
libraries hsql and HDBC. What is the difference between them? Why are
there two, and why are there sets of drivers for both (duplication of
effort?)? I've used both in the past but I can't discern a real big
difference (I used
monadLib looks nice, indeed, but the major problem with using it resides in
the fact that most of the libraries on hackage use MTL.
Must be tedious to have to use two monad libraries at the same time...
2010/7/6 Ertugrul Soeylemez e...@ertes.de
Gregory Crosswhite gcr...@phys.washington.edu
For some reason the generate function is not in QC2.
Here's a quick fix:
\begin{code}
import Test.QuickCheck.Gen
import System.Random
generate :: Int - StdGen - Gen a - a
generate n rnd (MkGen m) = m rnd' size
where
(size, rnd') = randomR (0, n) rnd
\end{code}
Perhaps it would be better
Ketil Malde wrote:
wren ng thornton w...@freegeek.org writes:
A bit more seriously: is there any listing anywhere of which extensions
Hugs supports?
Cabal has a partial listing embedded in its code, though I can't seem
to find a textual version at the moment. In general, Hugs has all the
Daniel Fischer wrote:
On Tuesday 06 July 2010 07:04:18, wren ng thornton wrote:
Cabal has a partial listing embedded in its code, though I can't seem to
find a textual version at the moment. In general, Hugs has all the
features of GHC 6.6: FFI, CPP, MPTCs, FunDeps, OverlappingInstances,...
I'm
My thanks to everyone who replied with their helpful comments. You are
right that I forgot to add the public inheritance on the C++ classes (that's
what happens when you write code in an email without passing it through a
compiler first).
I like the idea below, which is easy to understand. It
For some reason the generate function is not in QC2.
Here's a quick fix:
\begin{code}
import Test.QuickCheck.Gen
import System.Random
generate :: Int - StdGen - Gen a - a
generate n rnd (MkGen m) = m rnd' size
where
(size, rnd') = randomR (0, n) rnd
\end{code}
Perhaps it would be better
Simon Courtenage wrote:
I am porting a C++ program to Haskell. My current task is to take a class
hierarchy and produce something equivalent in Haskell
Did you define that task for yourself, or is someone else asking
you to do it?
There really isn't anything equivalent in Haskell. Typeclasses
Actually, I liked Tillmann Rendel's idea much better than my own one:
data A = A {do_x :: Int - Int - Int}
b = A {do_x = \x y - ...}
c = A {do_x = \x y - ...}
Simon Courtenage wrote:
My thanks to everyone who replied with their helpful comments. You are
right that I forgot to add the public
On Sun, Jul 4, 2010 at 10:43 AM, John Smith volderm...@hotmail.com wrote:
My MSc requires a project dissertation, which is expected to take about 800
hours. I would like to work on something which is of use to the Haskell
community. Any suggestions?
I'd love to see something like git-gui for
Hi all,
I am making use of the Data.Array.Repa module to achieve data-parallelism. On
running my program I get the error:
thread blocked indefinitely on an MVar operation
Two questions:
1. What could be some of the potential causes for the above error when the only
use of parallelism is Repa
Yves Parès limestr...@gmail.com wrote:
monadLib looks nice, indeed, but the major problem with using it
resides in the fact that most of the libraries on hackage use MTL.
Must be tedious to have to use two monad libraries at the same time...
In general this is a minor problem. Note that when
On Jul 6, 2010, at 12:23 AM, Steffen Schuldenzucker wrote:
Given the definition of a recursive function f in, say, haskell,
determine if f can be implemented in O(1) memory.
How are you supposed to handle integer arithmetic?
If you don't take the size of integers into account,
then since a
Yes but, for instance, every library which provides monad transformers will
provides a MTL's MonadTrans instance, not a monadLib's MonadT instance.
And since a library hides its types internals, you cannot write the MonadT
instances yourself.
For instance, I was planning to translate a little
Forwarding this message to the list.
No, I didn't think about the size of integers. For now, let all numbers
have some bounded size.
Original Message
Subject: Re: [Haskell-cafe] Criteria for determining if a recursive
function can be implemented in constant memory
Date:
If your integers have a bounded size, then your Turing machine is not Turing
complete and can't run a Haskell interpreter.
You might be tempted to just make the numbers really big, but bounded, and
then say that you can still run most interesting programs while skirting the
issue of non
On 7/5/2010 8:33 PM, Andrew Coppin wrote:
Tillmann Rendel wrote:
Hi Steffen,
Steffen Schuldenzucker wrote:
Given the definition of a recursive function f in, say, haskell,
determine if f can be implemented in O(1) memory.
Constant functions are implementable in O(1) memory, but interpreters
On 2010-06-19 16:43 +0100 (Sat), Max Bolingbroke wrote:
Curt Sampson had an experience report at ICFP last year about his
experience with Haskell for a real time application
(http://www.starling-software.com/blogimg/tsac/s5/2009-09-01-icfp.html).
He reported no issues with GC speed in
Simon Courtenage wrote:
This is for a project to port an open-source C++ library to haskell.
Great! We'd love to give you whatever support you need
for your efforts.
My initial plan is to more or less preserve the way the
library works in the first draft of the port and see how
far we can
On Mon, 05 Jul 2010 19:26:34 -0700, Ivan Miljenovic ivan.miljeno...@gmail.com
wrote:
Graphviz (http://graphviz.org/) has the option to convert provided Dot
code for visualising a graph into a canonical form. For example, take
the sample Dot code:
[snip]
I've recently thought up a way that I
Don,
Thank you for a new tool and great blog post !
I will surely use it.
You might be interested by the experiments section of a paper that we
submitted to the Haskell Symposium with Simon Marlow and Satnam Singh :
http://membres-liglab.imag.fr/termier/HLCM/hlcm.pdf
We studied the impact of
Yves Parès limestr...@gmail.com wrote:
Yes but, for instance, every library which provides monad transformers
will provides a MTL's MonadTrans instance, not a monadLib's MonadT
instance. And since a library hides its types internals, you cannot
write the MonadT instances yourself.
For
I was wondering : wouldn't it be possible that things like BaseM be
implemented on top of MTL?
Couldn't just one develop a package, say mtl-missing, that would contain the
functionnalities of monadLib, but compatible with MTL?
___
Haskell-Cafe mailing
Yves Parès limestr...@gmail.com wrote:
I was wondering : wouldn't it be possible that things like BaseM be
implemented on top of MTL?
Couldn't just one develop a package, say mtl-missing, that would
contain the functionnalities of monadLib, but compatible with MTL?
I don't know whether
On Mon, Jul 5, 2010 at 5:46 PM, Don Stewart d...@galois.com wrote:
Feedback and patches welcome!
Interesting.
Could this be combined with the ACOVEA compiler flag thing you did a
while back to produce a tool that would automatically improve
performance of programs on a fixed
warren.henning:
On Mon, Jul 5, 2010 at 5:46 PM, Don Stewart d...@galois.com wrote:
Feedback and patches welcome!
Interesting.
Could this be combined with the ACOVEA compiler flag thing you did a
while back to produce a tool that would automatically improve
performance of programs on a
On Tue, Jul 6, 2010 at 10:07 AM, Don Stewart d...@galois.com wrote:
A bit longer term, but yes. So far I've got individual approaches for
improving performance by finding:
* inlining points
* strictness flags
* `par` points
* LLVM flags
* RTS GC flags
They just need to be
Hi,
I have never used Text.HTML (except for stringToHtmlString) but any code
that works as CGI must work as FastCGI with appropriate runFastCGI call. Try
not to use nginx, it can't run fastcgi processes as far as I know. I use
lighttpd or Apache(mod_fastcgi)+nginx to run fastcgi programs.
On
Don Stewart wrote:
A bit longer term, but yes. So far I've got individual approaches for
improving performance by finding:
* inlining points
* strictness flags
* `par` points
* LLVM flags
* RTS GC flags
They just need to be integrated into a coherent set of tools and
Hi,
Just to add some details about the project I'm working on in case anyone is
interested. The project is called Quanthas and is being hosted on
sourceforge at http://sourceforge.net/projects/quanthas/. The aim of the
project is to produce a Haskell implementation of Quantlib (
On Tue, Jul 6, 2010 at 12:05 PM, Ertugrul Soeylemez e...@ertes.de wrote:
Yves Parès limestr...@gmail.com wrote:
I was wondering : wouldn't it be possible that things like BaseM be
implemented on top of MTL?
Couldn't just one develop a package, say mtl-missing, that would
contain the
* Simon Marlow marlo...@gmail.com [2010-07-06 13:00:36+0100]
The Haskell 2010 report is done! I've uploaded it to
www.haskell.org, and linked it from the main Haskell wiki:
http://www.haskell.org/haskellwiki/Language_and_library_specification
online HTML version:
On Fri, Jun 18, 2010 at 12:44 AM, Michael Snoyman mich...@snoyman.comwrote:
On Fri, Jun 18, 2010 at 5:03 AM, Erik de Castro Lopo
mle...@mega-nerd.commle%2...@mega-nerd.com
wrote:
Pascal? Yeah, I used to program in that about 30 years ago.
I actually got that response from someone.
You
I must have the same impediment. We should start a support group, that, or
give in and write a compiler. To add insult to injury,
I think it should be called Turbo Haskell.
That's true... I never noticed, because in French the two words get
pronounced very differently.
While we're on the
Hi,
there is a lot of buzz around functional dependencies on the mailing
list and Planet Haskell. I've read some of the tutorials and I think I
understand how they work but I still haven't figured out where they
can be useful.
* Can someone give me a real world (preferably hackagedb) example
Here's some code that uses them: http://gist.github.com/465918
This is a program that uses 4th-order Runge–Kutta to simulate some
physics. It keeps track of units of measurement as it does its work.
To do this, it uses type-level Peano numerals: every physical quantity
in this program is
Andrew Coppin schrieb:
I've always thought of compiler flags as being a fairly imprecise tool.
For example, -funbox-strict-fields applies a particular transformation
to EVERY STRICT FIELD IN THE ENTIRE PROGRAM. Which is fine if it's
always a win - but then, if it were always a win, there
Kevin Quick qu...@sparq.org writes:
On Mon, 05 Jul 2010 19:26:34 -0700, Ivan Miljenovic
ivan.miljeno...@gmail.com wrote:
Graphviz (http://graphviz.org/) has the option to convert provided
Dot
code for visualising a graph into a canonical form. For example,
take
the sample Dot code:
On Tue, Jul 6, 2010 at 7:15 PM, Ivan Lazar Miljenovic
ivan.miljeno...@gmail.com wrote:
As such, I probably won't be implementing the canonical form stuff any
time soon in graphviz, and might need to examine Graphviz's source code
to compare it and ensure that it's at least similar :s
I'm sorry
Felipe Lessa felipe.le...@gmail.com writes:
On Tue, Jul 6, 2010 at 7:15 PM, Ivan Lazar Miljenovic
ivan.miljeno...@gmail.com wrote:
As such, I probably won't be implementing the canonical form stuff any
time soon in graphviz, and might need to examine Graphviz's source code
to compare it and
On Tue, Jul 6, 2010 at 7:53 PM, Ivan Lazar Miljenovic
ivan.miljeno...@gmail.com wrote:
Felipe Lessa felipe.le...@gmail.com writes:
I'm sorry for being silly, but what's the motivation of having this
canonic form? =)
A few things come to mind:
* Easier to reason about, [...]
* Less
Hello,
I have the following directories set :
Project/
Project/Language
Project/Language/Copilot/
in Project there is the copilot.cabal file.
in Project/Language/Copilot there are a bunch of .hs files, including Main.hs
All the modules in these files are named Language.Copilot.NameOfTheFile for
Felipe Lessa felipe.le...@gmail.com writes:
On Tue, Jul 6, 2010 at 7:53 PM, Ivan Lazar Miljenovic
ivan.miljeno...@gmail.com wrote:
Felipe Lessa felipe.le...@gmail.com writes:
I'm sorry for being silly, but what's the motivation of having this
canonic form? =)
A few things come to mind:
*
robin morisset amulette...@yahoo.fr writes:
Hello,
I have the following directories set :
Project/
Project/Language
Project/Language/Copilot/
in Project there is the copilot.cabal file.
in Project/Language/Copilot there are a bunch of .hs files, including Main.hs
All the modules in these
Hi ! We have a question about about openAL. We would like to know if anybody
knows how to read a WAV file by chunks of a determined size, and after doing
some processing with a specific chunk send that same chunk back to the sound
card so we can play the whole WAV continiously (just like a music
Edward Kmett ekm...@gmail.com wrote:
You may want to review the thread here:
http://www.haskell.org/pipermail/libraries/2009-November/012833.html
The gist of it is, I would recommend sticking with MTL for right now,
but confining yourself to the portions of it that transformers +
monads-fd
Hello,
(Ivan Lazar Miljenovi)
Why not just have a Main.hs file?
As for that error message, do you have a main function? Are you sure
you were using --make?
thank you for taking the time for reply. A friend finally found the issue. The
main function in the Main module was ok, the problem
Does anybody know what are the analogous functions and data types in the
haskell library Sound.File.Sndfile of the libsndfile library in C ?
data type : SNDFILE
function: sf_open
function : sf_read_short
Thanks in advance,
--
Maria Gabriela Valdes G.
Linux Registered User #485743
Maria Gabriela Valdes wrote:
Does anybody know what are the analogous functions and data types in the
haskell library Sound.File.Sndfile of the libsndfile library in C ?
data type : SNDFILE
function: sf_open
function : sf_read_short
I have never used the Haskell bindings to that
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
On 7/6/10 15:37 , Oscar Finnsson wrote:
but can they also be on a form similar to
a b c d e f g h| b c - d e f | b d g - h
(i.e. d,e,f are decided by the b,c-combination while h is decided by
the b,d,g-combination)?
I think the answer to
On Tue, Jul 6, 2010 at 10:01 PM, Ertugrul Soeylemez e...@ertes.de wrote:
Edward Kmett ekm...@gmail.com wrote:
You may want to review the thread here:
http://www.haskell.org/pipermail/libraries/2009-November/012833.html
The gist of it is, I would recommend sticking with MTL for right
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