I have no idea if it is relevant, but I wrote a tiny proof assistant for
a hilbert style first order logic the other day.
http://repetae.net/Hilbert.hs
set hasUnicode to False at the top if your terminal doesn't support
unicode. fun what one can do in a few hundred lines of haskell..
Hi Ganesh,
manipulating predicate formulae was a central part of my PhD research. I
implemented some normalization and standarcization functions in Haskell -
inspired by term rewriting (like normalization to Boolean ring
representation) as well as (as far as I know) novell ideas (standardization
An even more painless way to do it is to edit the .cabal file (or just
cabal on Windows) in the cabal user directory (somwhere under the
AppData folder on windows), to have default values for
extra-include-dirs and extra-lib-dirs. Then you don't need to enter them
explicitly every time you use
Conal suggested to allow markdown/pandoc as the highlighting format
for Haddock, I liked the idea, but many didn't. I guess the only
workable solution would be to extend haddock to allow using an
external plugin to parse the actual formatting, stripping out leading
markers and somehow dealing
On Wed, Dec 3, 2008 at 10:17 AM, Matt Hellige [EMAIL PROTECTED] wrote:
From time to time, I've wanted to have a more pleasant way of writing
point-free compositions of curried functions.
I'd like to be able to write something like:
\ x y - f (g x) (h y)
This particular composition of f with
Hello List,
when I try to install the package plugins with cabal i get the following
error.
cabal: dependencies conflict: ghc-6.8.3 requires Cabal ==1.2.4.0 however
Cabal-1.2.4.0 was excluded because plugins-1.3.1 requires Cabal ==1.4.*
Is there a way to resolve this? Any ideas?
Sol.
Fellow Haskelleers,
it is my pleasure to announce the new release of the haskell-src-exts
package, version 0.4.4:
http://hackage.haskell.org/cgi-bin/hackage-scripts/package/haskell-src-exts-0.4.4
darcs get http://code.haskell.org/HSP/haskell-src-exts
The new feature in this release is support
On Thu, Dec 4, 2008 at 11:19 AM, Dan Piponi [EMAIL PROTECTED] wrote:
On Wed, Dec 3, 2008 at 10:17 AM, Matt Hellige [EMAIL PROTECTED] wrote:
From time to time, I've wanted to have a more pleasant way of writing
point-free compositions of curried functions.
I'd like to be able to write
I'd like to be able to write something like:
\ x y - f (g x) (h y)
I don't think
mathematicians have great notation for it either
Well, there is Combinatory Logic.
http://www.haskell.org/haskellwiki/Combinatory_logic
J.W.
___
On Thu, Dec 4, 2008 at 12:07 PM, Matt Hellige [EMAIL PROTECTED] wrote:
Finally, there's a further disadvantage to both of these approaches:
it seems to me that neither approach allows us to cross pipes. For
instance, we can't define flip using these techniques, or any deep
flip:
\ x y z - f
On Thu, Dec 4, 2008 at 10:21 AM, Matt Hellige [EMAIL PROTECTED] wrote:
\ f x y z - f x z y == id ~ flip
It's not clear to me whether your operad class can express this (or
whether operads in general can express this)
There exists an operad that can (at the cost of even more notation),
but
Niklas Broberg wrote:
Fellow Haskelleers,
it is my pleasure to announce the new release of the haskell-src-exts
package, version 0.4.4:
The full list of pragmas supported by 0.4.4 is: SOURCE, RULES,
DEPRECATED, WARNING, INLINE, NOINLINE, SPECIALISE, CORE, SCC,
GENERATED and UNPACK.
Ah,
So, the muse has taken me. I'm going to attempt to produce some animated
mathematical drawings involving lines and curves.
Gtk2hs has a Cairo binding that should make rendering the stuff fairly
straight-forward. So no problems there.
Now, what I *could* do is write a new Haskell program for
Andrew Coppin wrote:
It seems that the correct course of action is to design a DSL for
declaratively describing animated line art. Does anybody have ideas
about what such a thing might look like?
You could take a look at Fran [1] and Yampa [2] which both seem to do
animations in Haskell.
Hi,
That sounds like it might be quite useful. What I'm doing is generating
some predicates that involve addition/subtraction/comparison of integers
and concatenation/comparison of lists of some abstract thing, and then
trying to simplify them. An example would be simplifying
\exists
I am trying to define instance Show[MyType] so
show (x:xs :: MyType) would return a single string where substrings
corresponding to list elements will be separated by \n.
This would allow pretty printing of MyType list in several lines instead of
one, as default Show does for lists.
For example:
Dmitri O.Kondratiev wrote:
-- How to define Show [MyType] ?
Define instance Show MyType and implement not only show (for 1 value of
MyType) but also showList, which Show provides as well. You can do all
the magic in there.
HTH,
Martijn.
___
On Fri, 2008-12-05 at 01:27 +0300, Dmitri O.Kondratiev wrote:
I am trying to define instance Show[MyType] so
show (x:xs :: MyType) would return a single string where substrings
corresponding to list elements will be separated by \n.
This would allow pretty printing of MyType list in several
If you really, really wanted to define Show [ShipInfo], then putting
{-# LANGUAGE FlexibleInstances, OverlappingInstances #-}
at the beginning of your file would work. At the cost of using
overlapping instances, of course.
And at the cost of causing code like this:
f :: Show a = [a] -
On Thu, 2008-12-04 at 14:46 -0800, Ryan Ingram wrote:
If you really, really wanted to define Show [ShipInfo], then putting
{-# LANGUAGE FlexibleInstances, OverlappingInstances #-}
at the beginning of your file would work. At the cost of using
overlapping instances, of course.
And
1) Type families, associated types, synonyms... can anything replace
the use of TypeCast for explicit instance selection? Section 2, bullet
4 of http://www.haskell.org/haskellwiki/GHC/AdvancedOverlap indicates
a negative response. Any other ideas?
2) Any progress/options for kind polymorphism in
Sort of. I believe you can use type equality constraints to replace
the use of TypeCast; that is, in any code that looks like:
instance TypeCast a HTrue = ...
you can write
instance (a ~ HTrue) = ...
(at least, it has worked for me that way)
This at least makes me feel a bit more monadic
This is a haskell + networking question...
I have a multi threaded haskell server, which accepts client
connections, processes their requests, and returns results. It currently
works as desired, except where a client drops a connection whilst the
server is processing a request. In this
It seems that the correct course of action is to design a DSL for
declaratively describing animated line art. Does anybody have ideas
about what such a thing might look like?
Someone else already mentioned FRAN and it's ilk. But perhaps you don't
need something that fancy. If you implement your
What proposals are out there to address the issue of scoping
class methods? I always feel I must be careful, when exposing
a class definition that I want clients to be able to extend,
that I mustn't step on the namespace with semantically
appropriate but overly general names (e.g.
Tim Docker wrote:
One way of doing this would would be to maintain a separate thread that
is always reading from the client, and buffers until the main thread
needs the information. Whilst this would detect the remote close, it
also would potentially consume large amounts of memory to maintain
I have never run into such an issue. Typically classes tend to have the
smallest possible basis of methods. I would consider a class with more than
about 10 or 15 methods (including superclasses' methods) to indicate poor
design. That is just a rough heuristic.
But you're right, it would be
It's not that I like to have a lot of methods in a class, but
rather a lot of classes.
--
_jsn
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
Andrew,
I can think of several reasons why simple time-indexed animation may be
a bad idea. Some important aspects of animation are usually:
1) A main use case is playback, where time change is continuous and
monotonic.
2) Differential action is often much cheaper than time jumping (i.e.
No deep inheritance? Then what's the problem?
module X where
class Foo a where foo :: a - String
module Y where
class Foo' a where foo :: a - String
module Main where
import qualified X
import qualified Y
instance X.Foo Int where foo _ = X
instance Y.Foo' Int where foo _ = Y
It is known that
Quoth Tim Docker [EMAIL PROTECTED]:
| Hence I seem to need a means of detecting that a socket has been closed
| remotely, without actually reading from it. . Does anyone know how to do
| this? One reference I've found is this:
|
| http://stefan.buettcher.org/cs/conn_closed.html
|
| Apparently
Oh! Then there is no problem, after all.
--
_jsn
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
Hi,
you can browse my code
here.http://trac.informatik.uni-bremen.de:8080/hets/browser/trunk/Search/CommonIt
has become part of
Hets http://www.dfki.de/sks/hets the Heterogeneous Tool Set which is a
parsing, static analysis and proof management tool combining various tools
for different
On 05/12/2008, at 10:46 AM, Tim Docker wrote:
Someone else already mentioned FRAN and it's ilk. But perhaps you
don't
need something that fancy. If you implement your drawing logic as a
function from time to the appropriate render actions, ie
| import qualified Graphics.Rendering.Cairo as
More monadic?
--
_jsn
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
*** IFIP Working Conference on Domain Specific Languages (DSL WC) ***
July 15-17, 2009, Oxford
http://www.hope.cs.rice.edu/twiki/bin/view/WG211/DSLWC
* Call for Papers
Domain-specific languages are emerging as a fundamental component of
software engineering practice. DSLs are often
From the error below, I'm inferring that the RHS of the associated
type definition can only contain type variables from the instance
head, not the instance context. I didn't explicitly see this
restriction when reading the GHC/Type_families entry.
Could perhaps the a b - bn functional dependency
Hi,
I want to do some tracing, and I thought hat could help. Well hmake
and hat both could not been made with ghc 6.10
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
hi. i have a partial library for parsing ogg files here:
http://hpaste.org/12705
i have a question about an aspect of the code. in the function
checkHeader
there are a sequence of functions to check various elements in the
header of a ogg file.
2008/11/27 Simon Peyton-Jones [EMAIL PROTECTED]:
can you tell us about the most persuasive, fun application
you've encountered, for type families or functional dependencies?
Hi,
I certainly had fun with the Instant Insanity puzzle, in Monad.Reader issue 8:
Thanks - I'll take a look. One pre-emptive question: if I want to use it,
it'd be more convenient, though not insurmountable, if that code was
BSD3-licenced, since it will fit in better with the licence for camp
http://projects.haskell.org/camp, which I might eventually want to
integrate my
See slide 40 of Weaing the Hair Shirt: A Retrospective on Haskell,
Simon Peyton-Jones, POPL 2003
http://research.microsoft.com/Users/simonpj/papers/haskell-retrospective/index.htm
-- ryan
On Thu, Dec 4, 2008 at 7:04 PM, Jason Dusek [EMAIL PROTECTED] wrote:
More monadic?
--
_jsn
42 matches
Mail list logo
