Hi Yuras,
thanks for the link. That's the sad truth. I don't know the actual
reasons, but suspect there are many. Overtime work, fatigue, greed and
alienation which are ubiquitous it today's society are among them. I
admire people who nevertheless manage to work on open source projects in
Sven Panne wrote:
2013/9/27 Conal Elliott co...@conal.net:
[...] Am I mistaken about the current status? I.e., is there a solution for
Haskell GUI graphics programming that satisfies the properties I'm looking
for (cross-platform, easily buildable, GHCi-friendly, and
OpenGL-compatible)? [...]
Sven Panne wrote:
2013/9/27 Heinrich Apfelmus apfel...@quantentunnel.de:
Actually, I'm reading about WebGL right now, and it appears to me that it
should be very easy to support in Threepenny. [...]
I am not sure if WebGL is enough: WebGL is basically OpenGL ES 2.0,
which is again basically
[Transition in editorship of HCAR in progress!]
Dear all,
We would like to collect contributions for the 25th edition of the
Haskell Communities Activities Report
Thanks for the responses all.
I'm afraid the point about GHC.Generics got lost here. I'll respond and
then rename this as a specific library proposal.
I don't want to fix the world's Eq instances, but I am ok with requiring
that people derive Generic for any data they want to put in an LVar
Hi,
Ryan Newton wrote:
It is very hard for me to
see why people should be able to make their own Generic instances (that
might lie about the structure of the type), in Safe-Haskell.
I guess that lying Generics instances might arise because of software
evolution. Let's say we start with an
The abstract-par class has used multi-parameter type classes with fundeps:
http://hackage.haskell.org/package/abstract-par-0.3.1/docs/Control-Monad-Par-Class.html#g:1
And I'm trying to port it to use type families. But the following
combination seems to be completely unusable for me right now:
Oops, right after I sent I realized the answer ;-). I needed to delete one
character to uncurry the type function. That is:
type Future m
instead of
type Future m a
The fixed version is here:
On 10/2/13 4:55 PM, Omari Norman wrote:
I'm pleased to make the first public announcement of the availability of
Penny, a double-entry command-line accounting system.
Hurrah! Congrats Omari.
Will there be a 1.0 release, or will you be forever chasing that number
like me ?
(replicating what i said on the ghc-devs thread)
one thing i'm confused by, and this wasn't properly addressed in the prior
threads,
is
for a type like
data Annotated t ann = MkAnn t ann
would you consider the following unsafe?
instance Eq t = Eq ( Annotated t ann)
(==) (MkAnn t1 _)
On Sun, Oct 6, 2013 at 6:54 PM, Tillmann Rendel
ren...@informatik.uni-marburg.de wrote:
Hi,
Ryan Newton wrote:
It is very hard for me to
see why people should be able to make their own Generic instances (that
might lie about the structure of the type), in Safe-Haskell.
I guess that
I saw the the video on g+, it's especially nice with live
instruments. I noticed the code had a fair amount of stuff dealing
with limitations of the auto-bass, I assume you had to be careful not
to gum up its works. Is there a robotic drumset back there somewhere
too?
Also change ringing is new
Tillmann,
Thanks, that is in interesting use case for handwritten Generics.
I'm not fully dissuaded though, simply because:
(1) it can't be too common! Especially when you intersect the people who
have done or will do this with the people who care about SafeHaskell.
(Again, if they don't,
Rustom,
I've not looked at your forums link, what Vagif might be referring to is,
since you've already got your compiler installed, installing the platform
is /just/ compiling the remaining modules that are part of the platform. Of
course, building the compiler from source would take a very long
Oops my bad. The script downloads and installs binary, already compiled
ghc.
So it certainly does not take 2 hours, i just did it on 2 computers and it
takes less than a couple of minutes. I did not though install the entire
haskell platform, only ghc itself.
On Friday, October 4, 2013
On Fri, 4 Oct 2013 16:23:23 -0700, Charlie Paul charli...@gmail.com wrote:
Hello,
I'm looking for a combinator along the lines of
() :: Lens' a b - Lens' a b' - Lens' a (b,b')
I can see how it could lead to lenses that don't follow the laws, but
for Lenses which are somehow independent
Stijn van Drongelen wrote
On Fri, Oct 4, 2013 at 10:31 PM, Wvv lt;
vitea3v@
gt; wrote:
About newclass and compose data, we can do next:
newclass Foo [a] = FooList a where {containerMainipulation=...}
newclass Foo (Set a) = FooSet a where {containerMainipulation=...}
newclass
Hello all,
I have recently uploaded
argparserhttp://hackage.haskell.org/package/argparser-0.3.2,
a command line parser library. I made it because of 3 reasons:
- I am writing more and more scripts in haskell instead of python
- I did not want to use the ones presented
Charles,
I know you specifically asked for a Control.Lens combinator and I don't have
one for you, but I take the opportunity to show you how easy this is using
fclabels:
tupleUp :: f :- a
- f :- b
- f :- (a, b)
tupleUp a b = point $
(,) $ L.fst - a --
With a big help from the community, I've fixed my problem. I had to
include the extra-libraries when building the hcholmod library. I'll push
a new version later today.
Tad
On Fri, Oct 4, 2013 at 12:36 PM, Tad Doxsee tad.dox...@gmail.com wrote:
Hi,
I'm trying to create an FFI library to
Thanks, that looks useful! :)
On 04 Oct 2013, at 17:13, Erlend Hamberg ehamb...@gmail.com wrote:
While re-reading Brent Yorgey's Excellent Typeclassopedia I converted it
to Pandoc Markdown in order to be able to create an EPUB version. Having
a “real” e-book meant that I could comfortably
Very useful, thanks!
On Oct 4, 2013 9:13 AM, Erlend Hamberg ehamb...@gmail.com wrote:
While re-reading Brent Yorgey's Excellent Typeclassopedia I converted it
to Pandoc Markdown in order to be able to create an EPUB version. Having
a “real” e-book meant that I could comfortably read it on my
Hello, haskellers!
Here is HDBI-1.2 and some friends
There is class `FromRow` and `ToRow` from this version as well as
hdbi-conduit package. So, you can write your code like this:
{-# LANGUAGE
OverloadedStrings
, TemplateHaskell
#-}
import Control.Monad.IO.Class
import Data.Conduit
import
Hi,
I just read an article (sorry, it is in russian:
http://habrahabr.ru/post/196454/ ). The idea I found interesting: even
in big citied developers complain that nothing happens at their
location, but when you try to make an event -- only few of them want to
participate.
I never participate in
2013/9/27 Heinrich Apfelmus apfel...@quantentunnel.de:
Actually, I'm reading about WebGL right now, and it appears to me that it
should be very easy to support in Threepenny. [...]
I am not sure if WebGL is enough: WebGL is basically OpenGL ES 2.0,
which is again basically OpenGL 2.0 plus some
2013/9/27 Conal Elliott co...@conal.net:
[...] Am I mistaken about the current status? I.e., is there a solution for
Haskell GUI graphics programming that satisfies the properties I'm looking
for (cross-platform, easily buildable, GHCi-friendly, and
OpenGL-compatible)? [...]
Time warp! ;-)
Hi Spanish haskellers.
Maybe it is too late for the announcement, but we will have a meetup the
9th (next Tuesday).
Since the meetup group is devoted to functional programming in general, not
specifically Haskell, I will give an introduction to web programming in
Haskell: major platforms,
Hi all,
Let's say I want to #include a C header file in my Haskell library
just to read some macro definitions. The C header file also contains
some C code. Is there a way to load only macro definitions and not C
code in #include declarations in Haskell?
What I'm trying to do is I'm linking my
I think you've misunderstood Robin's point. The problem is that each of
these libraries is platform-specific. Writing an api on top of one is work
enough, but writing a cross-platform api that binds to the appropriate
platform-specific backend is a major undertaking.
On Oct 4, 2013 7:12 PM, Alp
Christopher Done wrote:
It's very easy to state this problem without enough details and mislead
people into providing a solution for a different problem, so I'll try to
include all the information and use-case. I need a function that can
store a value in a concrete opaque type. I know the type
On 4 October 2013 10:56, Heinrich Apfelmus apfel...@quantentunnel.de wrote:
In particular, the Locker stores arbitrary values like Dynamic , except
that values are extracted and removed with the help of a Key . This gets
rid of the Typeable constraint.
lock :: Key a - a - Locker
I can't
Christopher Done wrote:
On 4 October 2013 10:56, Heinrich Apfelmus apfel...@quantentunnel.de wrote:
In particular, the Locker stores arbitrary values like Dynamic , except
that values are extracted and removed with the help of a Key . This gets
rid of the Typeable constraint.
lock ::
| However, I want to write this as a core-to-core
| translation as a ghc-plugin. I want the definition go = putStrLn Hello
| World! to be translated to what I wrote above. Core cannot generate new
| names to be exported from a module, so go_ is now gone.
Wait... what do you mean Core cannot
Tom Ellis wrote:
On Wed, Oct 02, 2013 at 11:24:39AM +0200, Heinrich Apfelmus wrote:
I'm not sure whether the Eq instance you mention is actually
incorrect. I had always understood that Eq denotes an equivalence
relation, not necessarily equality on the constructor level.
There's a
While re-reading Brent Yorgey's Excellent Typeclassopedia I converted it
to Pandoc Markdown in order to be able to create an EPUB version. Having
a “real” e-book meant that I could comfortably read it on my e-book
reader and highlight text and take notes while reading. I also fixed
some minor
That's great — thank you!
On Fri, Oct 4, 2013 at 3:13 PM, Erlend Hamberg ehamb...@gmail.com wrote:
While re-reading Brent Yorgey's Excellent Typeclassopedia I converted it
to Pandoc Markdown in order to be able to create an EPUB version. Having
a “real” e-book meant that I could comfortably
Hi Chris,
Maybe this package (from Edward Kmett, surprisingly) could help:
http://hackage.haskell.org/package/constraints-0.3.3/docs/Data-Constraint.html?
Considering it kind of reifies the type class constraints, I'm wondering
whether you could use this to carry the constraints along the value
Hi guys,
I have been willing to have a nice GUI DSEL with good aesthetics for a
while. I think the hardest part wouldn't be the API, but really what
library we use underneath so that it's cross-platform and easy to install
for everyone. But I would love for something like that to happen and am
I don't think I would quite say haskell-game is quite relevant. For that
matter, the implementation on GitHub is not very good. It's too complicated
to scale and too specialized. I've been starting a fresh implementation,
since I learned a lot about what I really want to do writing that, but it
is
Yes, sorry, why I brought up haskell-game wasn't clear. I meant to say
there are already quite a few people willing to improve the situation of
graphics programming in Haskell (may it be GUI, games, visualization, ...).
And I think we should definitely talk to each other and try to come up with
My name is Charles Weitzer. I have a client with a startup quantitative
hedge fund located in Northern California. The Fund currently manages a very
healthy amount of capital. The founders have PhD's in Computer Science from
Stanford and in Statistics from Berkeley. They have made unpublished
Hi,
I'm trying to create an FFI library to CHOLMOD (
http://www.cise.ufl.edu/research/sparse/cholmod/) but am having problems.
My project is here: github.com/tdox/hcholmod. I can link an executable
with the build script in the examples directory (line 4). But line 7 does
not work (I get
Newclasses are something like instances, but out of scope. In a baggage.
We don't use them for interfere their functions.
This why newclasses never overlap each other and between them and any
instances.
We use newclasses to plug-in/connect to any related class or combine data
Replying to you
On Fri, Oct 4, 2013 at 10:31 PM, Wvv vite...@rambler.ru wrote:
Newclasses are something like instances, but out of scope. In a baggage.
So under the hood of GHC, newclasses would be partially filled in
dictionaries.
We already have too many classes: (...)
We can't divide all classes to
Dear Alp,
Alp Mestanogullari wrote:
[snip]
I have been willing to have a nice GUI DSEL with good aesthetics for a
while. I think the hardest part wouldn't be the API, but really what
library we use underneath so that it's cross-platform and easy to
install for everyone. But I would love for
Hi list,
What’s the preferred way of calling into Python from Haskell? I’ve
found MissingPy[0], but it seems to be somewhat bitrotten and a couple
of experiments yielded segfaults. There’s also the cpython
package[1], but that seems to require Python 3.3, and I’m trying to
call into code
Hello,
I'm looking for a combinator along the lines of
() :: Lens' a b - Lens' a b' - Lens' a (b,b')
I can see how it could lead to lenses that don't follow the laws, but
for Lenses which are somehow independent (like _1 and _2), it works
perfectly well. Is there a way in lens to specify this
Manuel-
Try my fork of the MissingPy library, I've brought it up to date and it
seems to function ok with current ghc/python.
www.github.com/arjuncomar/missingpy.git
The standalone branch also removes a lot of the extra dependencies
MissingPy has for extra functionality you probably don't need.
If these said libraries let us write a good API on top, then perfect! The
problem is to actually pick the ones fulfilling our needs I think, all the
major candidatures have pretty serious drawbacks, AFAIK.
On Sat, Oct 5, 2013 at 12:36 AM, Robin KAY komad...@gekkou.co.uk wrote:
Dear Alp,
Alp
I just upgraded my ubuntu laptop to 13.04 and haskell platform is gone!!
http://askubuntu.com/questions/286764/how-to-install-haskell-platform-for-ubuntu-13-04
What is the current status on this?
Is 13.10 going to correct this?
___
Haskell-Cafe mailing
13.04 has packages for ghc 7.6.2
It is easy to install latest haskell platform though.
Just run this script: https://github.com/chrisprobst/ubuntu-raring-haskell
On Friday, October 4, 2013 8:11:46 PM UTC-7, rusi wrote:
I just upgraded my ubuntu laptop to 13.04 and haskell platform is gone!!
On Sat, Oct 5, 2013 at 9:05 AM, Vagif Verdi vagif.ve...@gmail.com wrote:
13.04 has packages for ghc 7.6.2
It is easy to install latest haskell platform though.
Just run this script: https://github.com/chrisprobst/ubuntu-raring-haskell
I was hoping that something a little less painful than
That will give you only ghc 7.6.2. If you want latest haskell-platform,
source compile is the only option. And btw it is not THAT painful :)
You run the script, wait 2-3 minutes and tada!
On Friday, October 4, 2013 8:44:29 PM UTC-7, rusi wrote:
On Sat, Oct 5, 2013 at 9:05 AM, Vagif Verdi
On Sat, Oct 5, 2013 at 9:18 AM, Vagif Verdi vagif.ve...@gmail.com wrote:
That will give you only ghc 7.6.2. If you want latest haskell-platform,
source compile is the only option. And btw it is not THAT painful :)
You run the script, wait 2-3 minutes and tada!
Ok so someone is very confused
On Wed, 02 Oct 2013 12:24:25 +0200, Atze Dijkstra a...@uu.nl wrote:
Hi,
as for wxHaskell, it is currently maintained at
https://github.com/wxHaskell/wxHaskell, compilable with wxWidgets 2.9.5
and GHC 7.6. Work is underway to fix various bugs introduced over time
by changes in wxWidgets,
Your first two cases will be fixed in 7.10, as Applicative finally becomes
a superclass of Monad.
Sure, newclassses not about Applicative and Monads only.
This question is more wider.
Must Apply be a superclass of Bind?
Must Bind be a superclass of Monad?
So, must Monad has 2 superclasses at
I'm pleased to announce a new release of Yi, text editor written and
extensible in Haskell.
This release introduces new vim keybindings emulation. If all goes well, the
old one will be deprecated in future.
The advantages of the new emulation include support for visual block operations,
more
(I sent this to 'libraries' but Kim-Ee suggested adding Café, where so many
smart people hang out.)
Friends
Some of you will know that I've promised to give a talk about Edward's lens
libraryhttp://hackage.haskell.org/package/lens at the Haskell
Simon,
On Thu, 2013-10-03 at 08:07 +, Simon Peyton-Jones wrote:
If you are using the lens library yourself, could you spare a few
minutes to tell me how you are using it?
I'm not a heavy 'lens'-user (yet), and this might not be the most pretty
use-case from a theoretic point of view, but
Hi Simon,
An interesting use case is my time-lens library.
http://hackage.haskell.org/package/time-lens-0.3/docs/Data-Time-Lens.html
You can do things like
modL minutes (+5) (TimeOfDay 16 57 13)
17:02:13
But one has to be somewhat lenient about the lens laws here.
Roman
* Simon
Hi,
In a game I made recently, I had to load OBJ formatted models into an
OpenGL-friendly format. To do that, I'd parse the .obj, into a simple ADT,
and build the model into a vector. Here's where lens comes in: we want to
build separate vectors for the vertices, normals, UVs and faces indices.
On Thu, Oct 3, 2013 at 8:16 AM, Wvv vite...@rambler.ru wrote:
Your first two cases will be fixed in 7.10, as Applicative finally
becomes
a superclass of Monad.
Sure, newclassses not about Applicative and Monads only.
This question is more wider.
Must Apply be a superclass of Bind?
Must
Simon,
I've used lenses to manipulate URIs represented as strings in a structured way,
like:
modify (port . iso parsePrintUri) (+10) http://localhost:8070/index.html;
Of course using fclabels and not lens ;-)
Sebastiaan
On Oct 3, 2013, at 10:07 AM, Simon Peyton-Jones simo...@microsoft.com
Another great use of lenses is the lens-aeson library (not to be
confused with aeson-lens). It's technically based around prisms, though,
so it's outside the scope of your talk; but you may wish to at least
reference it - it makes working with JSON really elegant!
Hi Simon,
http://hackage.haskell.org/package/lens-datetime-0.2/docs/Data-Time-Lens.html
Read the top of the page.
aDay = fromGregorian 2013 08 22
aLocal = LocalTime aDay (TimeOfDay 13 45 28)
aUTC = UTCTime aDay 7458.9
aLocal ^. years
2013
aUTC ^. months
8
aDay ^. days
22
aLocal time .~
Lenses for nested sum types e.g. Either.
On 03/10/2013 6:08 PM, Simon Peyton-Jones simo...@microsoft.com wrote:
(I sent this to ‘libraries’ but Kim-Ee suggested adding Café, where so
many smart people hang out.)
** **
Friends
** **
Some of you will know that I’ve promised to
On Thu, 3 Oct 2013 22:06:22 +1000, Tony Morris tmor...@tmorris.net wrote:
Lenses for nested sum types e.g. Either.
I think those would be leaning more in the direction of prisms.
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
Hi Ben,
We made a small update
releasehttp://hackage.haskell.org/package/lvish-1.0.0.2that links
the github, and also links a mirror for the haddocks, since
something weird seems to be going on with Hackage 2:
http://www.cs.indiana.edu/~rrnewton/haddock/lvish/
Ryan,
You can use standalone-haddock[1] so that the links to other packages
are not broken.
[1]: http://documentup.com/feuerbach/standalone-haddock
Roman
* Ryan Newton rrnew...@gmail.com [2013-10-03 10:50:47-0400]
Hi Ben,
We made a small update
On 3 October 2013 10:57, Roman Cheplyaka r...@ro-che.info wrote:
An interesting use case is my time-lens library.
http://hackage.haskell.org/package/time-lens-0.3/docs/Data-Time-Lens.html
You can do things like
modL minutes (+5) (TimeOfDay 16 57 13)
17:02:13
But one has to be
Hi the list,
why do this function doesn't compile (parse error):
test :: Bool - IO ()
test foo = do
let bar = case foo of
True - Foo;
False - Bar
return ()
while this one does (just adding one space in front of True and False):
test :: Bool - IO ()
test foo = do
let bar
The first version has bar True and False all at the same indentation level.
As such they are seen as standalone expressions, rather than being nested
under the one introduced by bar.
See http://en.wikibooks.org/wiki/Haskell/Indentation
On Thu, Oct 3, 2013 at 8:31 PM, Corentin Dupont
On Thu, Oct 3, 2013 at 2:31 PM, Corentin Dupont
corentin.dup...@gmail.comwrote:
test :: Bool - IO ()
test foo = do
let bar = case foo of
True - Foo;
False - Bar
return ()
while this one does (just adding one space in front of True and False):
test :: Bool - IO ()
this should be fixed in plugins 1.5.4.0 which is now on hackage.
Thanks!
- jeremy
On Mon, Sep 16, 2013 at 2:49 AM, Petr Pudlák petr@gmail.com wrote:
Hi,
I'm playing with “plugins”, trying to evaluate a simple expression:
import Control.Monad
import System.Eval.Haskell
main = do
Yes, multi-class instances allow us write
type Monad a = (Applicative a, Bind a)
But at least 1 issue remains:
Applicative : pure; Monad: return
Bind : (-); Monad: (=)
With MultiClassInstances we could write only
instance Monad MyMonad where { pure= ...; (-)= ...}
But we
On Thu, Oct 3, 2013 at 9:44 PM, Brandon Allbery allber...@gmail.com wrote:
On Thu, Oct 3, 2013 at 2:31 PM, Corentin Dupont corentin.dup...@gmail.com
wrote:
test :: Bool - IO ()
test foo = do
let bar = case foo of
True - Foo;
False - Bar
return ()
while this one
Thanks to all for your replies!
I asked the question because I often make this kind of transformations
(please don't mind the non-sensical example):
test :: Bool - IO ()
test foo = do
bar - case foo of
True - return Foo
False - return Bar
return ()
into
test :: Bool - IO ()
Imagine if bar was a toplevel function
bar = case foo of
True - Foo;
False - Bar;
Keep in mind that indentation level starts at the function name, not at the
let keyword.
On Thu, Oct 3, 2013 at 2:31 PM, Corentin Dupont
corentin.dup...@gmail.comwrote:
Hi the list,
why do this function
There is not so much people in the game right now (only 3) and a little
more watching (20). Don't be shy and join!
On Thu, Oct 3, 2013 at 1:14 AM, Corentin Dupont
corentin.dup...@gmail.comwrote:
Hello everybody!
I released the third beta of Nomyx http://www.nomyx.net, the only game
where You
Lenses for nested ... types ...
Hi Simon/Edward/all,
The most compelling uses I've seen for lenses is back to Benjamin Pierce's
[et al] papers on Updatable Views. I think this is where the 'theory'
started(?), although similar ideas had kicked around the relational
database world for some
I don't really understand what a newclass is supposed to be.
On Thu, Oct 3, 2013 at 2:15 PM, Wvv vite...@rambler.ru wrote:
newclass Bind a = Monad a = BMonad a where { (=) = (-) }
I think this means that `BMonad` is supposed to be a new class that has
both Bind and Monad in scope, the
Apologies, that wasn't finished. I meant to say, does it mean that by
writing a BMonad instance a Monad instance would be automatically
generated? If so, that seems like it would cause conflicts in many cases.
Regardless, I think newclass needs to be better specified if you want
other people to
It's very easy to state this problem without enough details and mislead
people into providing a solution for a different problem, so I'll try to
include all the information and use-case. I need a function that can
store a value in a concrete opaque type. I know the type of the value
when I store
Thanks. I've just built GHC HEAD on Mac OS X Lion, and tested by
installing libraries with --enable-shared and loading a GLFW program
into GHCi. Using ghci -fno-ghci-sandbox, everything works great
including closing and restarting GL window multiple times. Can't wait
for the official release of
Yay!
Thanks Paul! It's always good to have more folks confirm the problems are
solved than not!
Another cool direction 7.8 will allow is using the various llvm ffi
bindings from ghci!
On Wednesday, October 2, 2013, Paul Liu wrote:
Thanks. I've just built GHC HEAD on Mac OS X Lion, and tested
I've heard good things about teespring. I gather it's like a kickstarter
but specifically for t-shirts. They seem to have some procedures[1] in
place specifically for non-profit organizations, which might be a good
option for supporting haskell.org.
[1]: http://teespring.com/solutions
Ryan Newton wrote:
Here are some examples:
-
data Foo = Bar | Baz
instance Eq Foo where
_ == _ = True
instance Ord Foo where
compare Bar Bar = EQ
compare Bar Baz = LT
compare _ _ = error I'm partial!
On Wed, Oct 02, 2013 at 11:24:39AM +0200, Heinrich Apfelmus wrote:
I'm not sure whether the Eq instance you mention is actually
incorrect. I had always understood that Eq denotes an equivalence
relation, not necessarily equality on the constructor level.
There's a difference between
* Heinrich Apfelmus apfel...@quantentunnel.de [2013-10-02 11:24:39+0200]
In other words, equality of abstract data types is different from
equality of algebraic data types (constructors). I don't think you'll
ever be able to avoid this proof obligation that the public API of an
abstract data
Hi,
as for wxHaskell, it is currently maintained at
https://github.com/wxHaskell/wxHaskell, compilable with wxWidgets 2.9.5 and GHC
7.6. Work is underway to fix various bugs introduced over time by changes in
wxWidgets, but we (i.e. https://github.com/wxHaskell?tab=members) hope to
release
Hi,
Roman Cheplyaka wrote:
It still seems to fit nicely into Safe Haskell. If you are the
implementor of an abstract type, you can do whatever you want in the Eq
instance, declare your module as Trustworthy, and thus take the
responsibility for soundness of that instance w.r.t. your public API.
Hi,
I'm trying to get things up and running but I keep having problems with the
following.
When I follow the instructions on
https://github.com/acowley/roshask/wiki/Getting-Started
I run into the following:
tijn@tt:~/MyPackage$ roshask dep
Looking for [std_msgs], dependencies of
* Tillmann Rendel ren...@informatik.uni-marburg.de [2013-10-02 13:19:38+0200]
Hi,
Roman Cheplyaka wrote:
It still seems to fit nicely into Safe Haskell. If you are the
implementor of an abstract type, you can do whatever you want in the Eq
instance, declare your module as Trustworthy, and
I do think something has to be done to have an Eq and Ord with more strict
laws.
* Operators in Eq and Ord diverge iff any of their parameters are bottom.
* The default definitions of (/=), (), () and `compare` are law.
* (==) is reflexive and transitive
* (=) is antisymmetric ((x = y y = x)
On Wed, 2 Oct 2013 15:46:42 +0200, Stijn van Drongelen rhym...@gmail.com
wrote:
I do think something has to be done to have an Eq and Ord with more strict
laws.
* Operators in Eq and Ord diverge iff any of their parameters are bottom.
* The default definitions of (/=), (), () and `compare`
Only for meanings of better which do not imply as good performance.
On 2 October 2013 14:46, Stijn van Drongelen rhym...@gmail.com wrote:
I do think something has to be done to have an Eq and Ord with more strict
laws.
* Operators in Eq and Ord diverge iff any of their parameters are
On Wed, Oct 2, 2013 at 3:49 PM, Niklas Haas hask...@nand.wakku.to wrote:
On Wed, 2 Oct 2013 15:46:42 +0200, Stijn van Drongelen rhym...@gmail.com
wrote:
I do think something has to be done to have an Eq and Ord with more
strict
laws.
* Operators in Eq and Ord diverge iff any of their
Hi,
The best low-level foundation libraries that I know of are the
Enlightenment Foundation Libraries (EFL) [1,2]. They are cross-platform
: they support many backends (X11, OpenGL, framebuffer...) and are used
on desktops and mobile devices (even to provide games on the French Free
ISP
On Wed, Oct 02, 2013 at 03:46:42PM +0200, Stijn van Drongelen wrote:
* Operators in Eq and Ord diverge iff any of their parameters are bottom.
What's the benefit of this requirement, as opposed to, for example
False = _ = True
...
Tom
___
* Stijn van Drongelen rhym...@gmail.com [2013-10-02 15:46:42+0200]
I do think something has to be done to have an Eq and Ord with more strict
laws.
* Operators in Eq and Ord diverge iff any of their parameters are bottom.
This outlaws the Eq instances of lists, trees, and other (co)recursive
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