On Mon, Apr 29, 2013 at 8:35 PM, Duncan Coutts duncan.cou...@googlemail.com
wrote:
On Mon, 2013-04-29 at 20:19 +0200, Gábor Lehel wrote:
Thanks for the explanation. I looked at your thesis previously, but only
read through a couple of sections (including the one about concatMap). I
might
On Mon, Apr 29, 2013 at 8:40 PM, Dan Doel dan.d...@gmail.com wrote:
On Mon, Apr 29, 2013 at 10:05 AM, Duncan Coutts
duncan.cou...@googlemail.com wrote:
On Thu, 2013-04-25 at 00:52 +0200, Gábor Lehel wrote:
On Wed, Apr 24, 2013 at 7:56 PM, Bryan O'Sullivan b...@serpentine.com
wrote
On Mon, Apr 29, 2013 at 4:05 PM, Duncan Coutts duncan.cou...@googlemail.com
wrote:
On Thu, 2013-04-25 at 00:52 +0200, Gábor Lehel wrote:
On Wed, Apr 24, 2013 at 7:56 PM, Bryan O'Sullivan b...@serpentine.com
wrote:
On Wed, Apr 24, 2013 at 10:47 AM, Duncan Coutts
duncan.cou
I've wondered this too. What would have been wrong with a simple
source-to-source translation, where a constraint on the datatype itself
translates to the same constraint on each of its constructors? Perhaps it
would be unintuitive that you would have to pattern match before gaining
access to the
:: C a = a - Foo a
is an illegal definition. It can only be translated to a non-newtype data
declaration, which changes the semantics.
On Thu, Apr 25, 2013 at 10:35 AM, Gábor Lehel illiss...@gmail.com wrote:
I've wondered this too. What would have been wrong with a simple
source-to-source
On Wed, Apr 24, 2013 at 7:56 PM, Bryan O'Sullivan b...@serpentine.comwrote:
On Wed, Apr 24, 2013 at 10:47 AM, Duncan Coutts
duncan.cou...@googlemail.com wrote:
I address it briefly in my thesis [1], Section 4.8.2. I think it's a
fundamental limitation of stream fusion.
See also concat,
the final consumer
is recursive.
concat [[1,2,3],[4,5],[],[6,7]]
probably looks something like:
Yield 1, Yield 2, Yield 3, Skip, Yield 4, Yield 5, Skip, Skip, Yield
6, Yield 7, Skip, Done
-- Dan
On Wed, Apr 24, 2013 at 6:52 PM, Gábor Lehel illiss...@gmail.com wrote:
On Wed, Apr
http://hackage.haskell.org/package/algebra
--
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{-# LANGUAGE UndecidableInstances #-}
class OldConstraint a = NewtypedConstraint a
instance OldConstraint a = NewtypedConstraint a
perhaps?
Nice thing is you don't even need to do wrapping/unwrapping, like you do
with data newtypes.
On Tue, Mar 12, 2013 at 2:18 PM, Roman Cheplyaka
On Tue, Dec 18, 2012 at 11:03 PM, Christopher Howard
The original link I gave
http://www.haskellforall.com/2012_08_01_archive.html purposely skipped
over any discussion of objects, morphisms, domains, and codomains. The
author stated, in his first example, that Haskell functions are a
On Sun, Nov 25, 2012 at 9:36 AM, Takayuki Muranushi muranu...@gmail.com wrote:
Is it possible to write
type family SameType a b :: Bool
which returns True if a and b are the same type, and False otherwise?
I encountered this problem when I was practicing promoted lists and
tuples in
On Sat, Nov 10, 2012 at 4:00 AM, Johan Tibell johan.tib...@gmail.com wrote:
As for type classes, I don't think we use them enough. Perhaps because
Haskell wasn't developed as an engineering language, some good software
engineering principles (code against an interface, not a concrete
On Fri, Sep 28, 2012 at 6:36 PM, Francesco Mazzoli f...@mazzo.li wrote:
I would expect this to work, maybe with some additional notation (a la
ScopedTypeVariables)
{-# LANGUAGE FunctionalDependencies #-}
{-# LANGUAGE MultiParamTypeClasses #-}
class Foo a b | a - b
class
On Sun, Jul 8, 2012 at 3:05 AM, Nicolas Trangez nico...@incubaid.com wrote:
On Sun, 2012-07-08 at 01:40 +0200, Gábor Lehel wrote:
unsafeXorSSE42 :: (Storable a,
SV.AlignedToAtLeast SV.A16 o1, SV.Alignment o1,
SV.AlignedToAtLeast SV.A16 o2, SV.Alignment o2,
SV.AlignedToAtLeast
On Sat, Jul 7, 2012 at 9:13 PM, Nicolas Trangez nico...@incubaid.com wrote:
- Currently Alignment phantom types (e.g. A8 and A16) are not related to
each other: a function (like Data.Vector.SIMD.Algorithms.unsafeXorSSE42)
can have this signature:
unsafeXorSSE42 :: Storable a = SV.Vector
On Sat, Jul 7, 2012 at 9:59 PM, Gábor Lehel illiss...@gmail.com wrote:
class AlignedToAtLeast n a
instance AlignedToAtLeast A1 A1
instance AlignedToAtLeast A4 A1
instance AlignedToAtLeast A4 A4
instance AlignedToAtLeast A8 A1
instance AlignedToAtLeast A8 A4
instance AlignedToAtLeast A8 A8
On Sun, Jul 8, 2012 at 12:21 AM, Nicolas Trangez nico...@incubaid.com wrote:
On Sat, 2012-07-07 at 21:59 +0200, Gábor Lehel wrote:
An alternative solution is to encode all of the alignments in unary,
which is more general; if they're all going to be a power of two you
can store just
.
I wrote some example code and a note about this stuff:
https://github.com/dterei/SafeHaskellExamples/tree/master/typeclasses
Cheers,
David
On 18 May 2012 06:58, Gábor Lehel illiss...@gmail.com wrote:
I have a related-seeming question:
Say I have a type class with methods, and some
On Tue, Jun 5, 2012 at 2:25 PM, Gábor Lehel illiss...@gmail.com wrote:
The encoded version would be:
instance (f a b) = FMap f (HJust a) (HJust b)
where type f :$: (HJust a) = HJust b
and I think this actually demonstrates a *different* limitation, namely that
The RHS of an associated
On Thu, Jun 7, 2012 at 1:42 PM, Miguel Mitrofanov miguelim...@yandex.ru wrote:
Hi cafe!
The ConstraintKinds extension makes it possible to create classes of classes,
like this:
class F c where cfmap :: c f = (a - b) - f a - f b
instance F Functor where cfmap = fmap
instance F Monad where
On Tue, Jun 5, 2012 at 4:18 AM, Etienne Laurin etie...@atnnn.com wrote:
Thanks for the idea. Here it is.
http://hackage.haskell.org/trac/ghc/wiki/TFvsFD
I posted my comments on the matter along with many additional comments
and examples that I found.
Thanks!
One part is confusing me.
In
On Tue, Jun 5, 2012 at 5:29 PM, Bas van Dijk v.dijk@gmail.com wrote:
Hello,
I have the following program:
--
{-# LANGUAGE ConstraintKinds #-}
{-# LANGUAGE ExistentialQuantification #-}
{-# LANGUAGE
On Fri, Jun 1, 2012 at 4:37 PM, James Cook mo...@deepbondi.net wrote:
On Jun 1, 2012, at 6:11 AM, Gábor Lehel wrote:
On Fri, Jun 1, 2012 at 6:29 AM, wren ng thornton w...@freegeek.org wrote:
TypeFamilies (aka TFs)
These are really nifty and they're all the rage these days
On Fri, Jun 1, 2012 at 6:29 AM, wren ng thornton w...@freegeek.org wrote:
TypeFamilies (aka TFs)
These are really nifty and they're all the rage these days. In
a formal sense they're equivalent to fundeps, but in practice
they're weaker than fundeps.
Is that still
On Fri, May 25, 2012 at 7:06 AM, AntC anthony_clay...@clear.net.nz wrote:
But it looks like the work SPJ pointed to is using closed style. If all
they're trying to do is support HList and similar, I guess that's good enough.
I tried to explain all this the best part of a year ago. (Admittedly
I have a related-seeming question:
Say I have a type class with methods, and some functions implemented
on top of it. The class methods are inherently unsafe. Instances of
the class are supposed to satisfy some conditions, and if those
conditions are met, the functions built on top are safe.
So
On Sat, Apr 21, 2012 at 6:05 PM, Bas van Dijk v.dijk@gmail.com wrote:
Hi,
I just found out that with the new ConstraintKinds extension we can
parameterize the constraint of an existentially quantified type:
{-# LANGUAGE KindSignatures, ConstraintKinds, ExistentialQuantification #-}
On Thu, Apr 5, 2012 at 8:59 PM, Tillmann Rendel
ren...@informatik.uni-marburg.de wrote:
Paul R wrote:
I am curious what are interesting use-cases for that? Symbolic
analysis? self-compilers?
Optimization. For example, imagine the following definition of function
composition:
map f . map
2012/2/20 José Pedro Magalhães j...@cs.uu.nl:
One last issue: Say I have a type like: data T = C !Int
Currently GHC Generics can't express the strictness annotation. This
means that your deepseq will unnecessarily evaluate the Int (since it
will always be evaluated already). It would be nice
On Mon, Feb 20, 2012 at 4:41 AM, AntC anthony_clay...@clear.net.nz wrote:
Folks, I've put my 'Record in Haskell' proposal on the wiki
http://hackage.haskell.org/trac/ghc/wiki/Records as suggestion 5 Declared
Overloaded Record Fields.
Thanks to the voiciferousness on this thread, dot notation
On Fri, Feb 10, 2012 at 5:31 AM, Evan Laforge qdun...@gmail.com wrote:
You can also enforce invariants, etc. It would be a shame to have a
nice record update syntax only to be discouraged from using it because
it would tie you too tightly to the current shape of the data
structure. There
On Tue, Feb 7, 2012 at 7:23 AM, Mikhail Vorozhtsov
mikhail.vorozht...@gmail.com wrote:
Even better, you can write
type ExistentialWith c e = (Existential e, c ~ ConstraintOf e)
instead of
class (Existential e, c ~ ConstraintOf e) = ExistentialWith c e
instance (Existential e, c ~
2012/2/7 Mikhail Vorozhtsov mikhail.vorozht...@gmail.com:
Ah, sorry, I got sloppy. Have you encountered situations where partial
application of such constraint aliases becomes a problem?
In the particular case of the Existential class I'm not sure (it's
hard to imagine a real-world application
those Kind extensions that enable you to pass a
typeclass as a type parameter...
However, have you considered putting the Data.Exists.Default module in a
separate package? That would reduce the dependencies for those who just need
Exists and Existential.
2012/2/5 Gábor Lehel illiss...@gmail.com
2012/2/6 Tillmann Rendel ren...@informatik.uni-marburg.de:
Hi,
Gábor Lehel wrote:
data E = forall a. C a = E a
I don't know if anyone's ever set out what the precise requirements
are for a type class method to be useful with existentials.
More than you seem to think. For example
There's a common pattern in Haskell of writing:
data E where E :: C a = a - E
also written
data E = forall a. C a = E a
I recently uploaded a package to Hackage which uses the new
ConstraintKinds extension to factor this pattern out into an Exists
type parameterized on the constraint, and also
On Fri, Feb 3, 2012 at 10:30 AM, AntC anthony_clay...@clear.net.nz wrote:
You seem to be not alone in wanting some special syntax for applying field
selectors (see other posts on this thread). H98 field selectors don't do this,
they're just functions.
And there's me bending over backwards to
On Fri, Feb 3, 2012 at 2:37 PM, AntC anthony_clay...@clear.net.nz wrote:
Do people really write code with huge pile-ups of functions prefix upon
prefix? Wouldn't that be confusing even when it's unidirectional?
Not really. Pipeline-like chains where you apply each function to the
result of the
On Tue, Jan 31, 2012 at 2:51 AM, Richard O'Keefe o...@cs.otago.ac.nz wrote:
On the other hand, a designed-to-be-strict language-and-libraries
with close-to-Haskell *syntax* would be nice. I recently
described F# as combining the beauty of Caml with the functional
purity of C# -- both of
On Sun, Dec 25, 2011 at 9:19 PM, Eugene Kirpichov ekirpic...@gmail.com wrote:
Hello Heinrich,
Thanks, that's sure some food for thought!
A few notes:
* This is indeed analogous to Iteratees. I tried doing the same with
Iteratees but failed, so I decided to put together something simple of
On Mon, Dec 19, 2011 at 8:20 PM, Robert Clausecker fuz...@gmail.com wrote:
Image you would create your own language with a paradigm similar to
Haskell or have to chance to change Haskell without the need to keep any
compatibility. What stuff would you add to your language, what stuff
would you
On Wed, Dec 7, 2011 at 1:07 PM, Dmitry Kulagin dmitry.kula...@gmail.com wrote:
For short, type synonyms work for mere aliases, but not for full-fledged
type-level non-inductive functions. And sometimes we intuitively want to
use them as such.
Thank you, Yves! It is now more clear for me.
I don't want a bad mascot. I do want a good mascot.
If you must count me down for one side or the other, count this as a yes.
On Wed, Nov 23, 2011 at 8:11 PM, heathmatlock heathmatl...@gmail.com wrote:
Question: Do you want a mascot?
Answers:
Yes
No
--
This is an attempt to figure out if
On Tue, Nov 22, 2011 at 6:22 AM, Jeremy Shaw jer...@n-heptane.com wrote:
I think the artwork is nice, but I am not sure that a lamb is an
appropriate mascot for Haskell.
A mascot is supposed to represent characteristics, emotions, or
desires that a particular group of people aspire to have,
On Mon, Nov 21, 2011 at 2:52 PM, Karol Samborski edv.ka...@gmail.com wrote:
2011/11/21 Karol Samborski edv.ka...@gmail.com:
Hi all,
This is my sister's proposition:
http://origami.bieszczady.pl/images/The_Lamb_Da.png
What do you think?
Second version:
On Tue, Nov 22, 2011 at 4:40 PM, Karol Samborski edv.ka...@gmail.com wrote:
And what about a cat? The cat is associated with elegance and a kind of magic.
Please take a look: http://origami.bieszczady.pl/images/kot.png
Best,
Karol Samborski
That's true, and I did think of it. But I don't
On Tue, Sep 13, 2011 at 4:58 PM, Grigory Sarnitskiy sargrig...@ya.ru wrote:
Is there a way to make the following code working?
{-# LANGUAGE TypeFamilies #-}
data family Foo a
data instance (Num a) = Foo a = A a deriving Show
data instance (Fractional a) = Foo a = B a deriving Show
On Tue, Sep 13, 2011 at 4:58 PM, Grigory Sarnitskiy sargrig...@ya.ru wrote:
Is there a way to make the following code working?
{-# LANGUAGE TypeFamilies #-}
data family Foo a
data instance (Num a) = Foo a = A a deriving Show
data instance (Fractional a) = Foo a = B a deriving Show
On Mon, Jul 25, 2011 at 9:35 AM, Thomas Schilling
nomin...@googlemail.com wrote:
On 25 July 2011 08:22, Paul R paul.r...@gmail.com wrote:
Hi Café,
Thomas I think () is fairly uncontroversial because:
Thomas (...)
Thomas 2. It's abstract. i.e., no intended pronunciation
How can that be an
2011/7/25 Yves Parès limestr...@gmail.com:
2011/7/25 Paul R paul.r...@gmail.com
Some references state that the monoid binary operation is often named
dot or times in english. That does not mean the operator must be
`dot`, `times`, (.) or (x) but at least the doc should provide
a single,
On Wed, Jul 6, 2011 at 5:24 PM, Jason Dagit dag...@gmail.com wrote:
On Wed, Jul 6, 2011 at 8:09 AM, Simon Marlow marlo...@gmail.com wrote:
On 06/07/2011 15:42, Jason Dagit wrote:
On Wed, Jul 6, 2011 at 2:23 AM, Simon Marlowmarlo...@gmail.com wrote:
On 06/07/2011 07:37, Jason Dagit wrote:
2011/7/6 Gábor Lehel illiss...@gmail.com:
On Wed, Jul 6, 2011 at 5:24 PM, Jason Dagit dag...@gmail.com wrote:
On Wed, Jul 6, 2011 at 8:09 AM, Simon Marlow marlo...@gmail.com wrote:
On 06/07/2011 15:42, Jason Dagit wrote:
On Wed, Jul 6, 2011 at 2:23 AM, Simon Marlowmarlo...@gmail.com wrote
2011/7/6 Gábor Lehel illiss...@gmail.com:
2011/7/6 Gábor Lehel illiss...@gmail.com:
On Wed, Jul 6, 2011 at 5:24 PM, Jason Dagit dag...@gmail.com wrote:
On Wed, Jul 6, 2011 at 8:09 AM, Simon Marlow marlo...@gmail.com wrote:
On 06/07/2011 15:42, Jason Dagit wrote:
On Wed, Jul 6, 2011 at 2:23
2011/7/6 Donn Cave d...@avvanta.com:
Quoth =?ISO-8859-1?Q?G=E1bor_Lehel?= illiss...@gmail.com,
...
Stated another way: I suspect most GUI libraries don't really actually
care that you only execute GUI code from the main OS thread, as much
as they care that only one (thread-unsafe) GUI
On Tue, Jun 7, 2011 at 3:05 PM, James Cook mo...@deepbondi.net wrote:
On Jun 6, 2011, at 10:57 PM, Chris Smith wrote:
I got asked a question today about why Control.Applicative is labeled as
experimental on Hackage. Perhaps that field is something of a failed
experiment, and it remaining
On Mon, Jun 6, 2011 at 7:52 AM, Yitzchak Gale g...@sefer.org wrote:
Scott Lawrence wrote:
More specifically, I have
class Model m a | m - a where ...
class Entropy d where ...
instance (Model m a) = Entropy m where ...
The first line requires MultiParamTypeClasses and
On Sun, May 8, 2011 at 7:14 AM, Nicholas Tung nt...@ntung.com wrote:
Dear all,
I'd like to write a function maybeShow :: a - Maybe String, which
runs show if its argument is of class Show.
The context and motivation for this are as follows. I have a GADT type
which encapsulates
It works if I replace the 'bool' return type of 'finished' with int
and CInt on the C++ and Haskell side, respectively, and test for (/=
0).
On Mon, May 2, 2011 at 9:35 PM, Huynh Huu Long
long.upc...@googlemail.com wrote:
Hi,
I tried to access C++ iterators from Haskell via the FFI. There are
Hi all,
I would very much like to apply for a Summer of Code project this
year; however, I'm having trouble nailing down a project which is both
(a) of appropriate scope and (b) which interests and motivates me.
There's also obviously the question of needing a mentor for the
project. Regarding
2011/4/1 Gershom Bazerman gersh...@gmail.com:
On Apr 1, 2011, at 7:52 AM, Gábor Lehel wrote:
The two projects I've been able to think of which seem like they
*might* be appropriate are: integrating the standard 'deriving'
mechanism with Template Haskell to support deriving custom classes
2011/4/1 Johan Tibell johan.tib...@gmail.com:
Hi Gábor,
There are a few non-Cabal projects on the ideas list
(http://hackage.haskell.org/trac/summer-of-code/report/1). Just
thought I mentioned it in case you missed it.
I saw it :)
2011/4/1 Gábor Lehel illiss...@gmail.com:
Alternately
2011/4/1 Johan Tibell johan.tib...@gmail.com:
2011/4/1 Gábor Lehel illiss...@gmail.com:
Oh, hmm. Good idea. Should've cross-posted from the beginning :|.
What's the accepted etiquette here? Forward the original message? Send
a short heads-up with a link to this thread in the archives?
I'd
On Thu, Mar 17, 2011 at 11:14 PM, Andrew Coppin
andrewcop...@btinternet.com wrote:
Right. So somebody else came up with an idea similar to mine, but since
nobody could agree on anything more than a rough idea, nothing actually
got
done...(?)
Well, I also got the sense that it would be more
On Wed, Mar 30, 2011 at 6:52 AM, Tad Doxsee tad.dox...@gmail.com wrote:
Greg,
Thanks for your help. Is there any significant difference between
using existential quantification
data ShapeD = forall s. ShapeC = ShapeD s
versus a GADT
data ShapeD where
ShapeD :: ShapeC s = s - ShapeD
On Tue, Mar 22, 2011 at 3:14 PM, Mario Blažević mblaze...@stilo.com wrote:
The first version of incremental-parser has been released on Hackage
[1]. It's yet another parser combinator
library, providing the usual set of Applicative and Monad combinators. Apart
from this, it has three
Necroing this thread because I just noticed there's a (rather old!)
bug report which covers much of the same ground and doesn't seem to
have been mentioned by anyone:
http://hackage.haskell.org/trac/ghc/ticket/1349
2011/2/8 Gábor Lehel illiss...@gmail.com:
2011/2/8 Ketil Malde ke...@malde.org
On Thu, Mar 17, 2011 at 10:37 PM, Andrew Coppin
andrewcop...@btinternet.com wrote:
On 17/03/2011 12:11 PM, Gábor Lehel wrote:
Necroing this thread because I just noticed there's a (rather old!)
bug report which covers much of the same ground and doesn't seem to
have been mentioned by anyone
On Wed, Mar 9, 2011 at 5:26 PM, Remi Turk rt...@science.uva.nl wrote:
On Tue, Mar 08, 2011 at 01:01:58PM +0100, Gábor Lehel wrote:
On Sun, Mar 6, 2011 at 2:38 PM, Remi Turk rt...@science.uva.nl wrote:
Where?
Hackage: http://hackage.haskell.org/package/cinvoke
Cheers, Remi
[1] http
On Sun, Mar 6, 2011 at 2:38 PM, Remi Turk rt...@science.uva.nl wrote:
I am happy to finally announce cinvoke 0.1, a binding to the
C library cinvoke[1], allowing functions to be loaded and called
whose names and types are not known before run-time.
Why?
Sometimes you can't use the Haskell
On Mon, Mar 7, 2011 at 7:32 PM, Remi Turk rt...@science.uva.nl wrote:
On Mon, Mar 07, 2011 at 09:41:27AM +, Max Bolingbroke wrote:
Hi Remi,
On 6 March 2011 13:38, Remi Turk rt...@science.uva.nl wrote:
I am happy to finally announce cinvoke 0.1, a binding to the
C library cinvoke[1],
On Mon, Feb 28, 2011 at 12:41 PM, wren ng thornton w...@freegeek.org wrote:
On 2/28/11 2:43 AM, Yitzchak Gale wrote:
You have written a large software system in Haskell. Wishing to
play to Haskell's strength, you have structured your system
as a series of composable layers. So you have data
On Mon, Feb 14, 2011 at 12:06 PM, Pedro Vasconcelos p...@dcc.fc.up.pt wrote:
On Sat, 12 Feb 2011 19:38:31 +0530
C K Kashyap ckkash...@gmail.com wrote:
Anyway, how can one go about explaining to an imperative programmer
with no FP exposure - what aspect of Haskell makes it easy to
refactor?
On Tue, Feb 15, 2011 at 12:48 AM, Max Bolingbroke
batterseapo...@hotmail.com wrote:
On 14 February 2011 21:43, Patrick Bahr pa...@arcor.de wrote:
Am I doing something wrong or is it not possible for GHC to dispatch a rule
according to type class constraints?
As you have discovered this is not
2011/2/7 Richard O'Keefe o...@cs.otago.ac.nz:
On 8/02/2011, at 3:47 AM, Gábor Lehel wrote:
I dunno. As a language extension, would - let's call it BangTypes - be
backwards-incompatible in any way?
Let's look at an intermediate step first, BangFunctions.
What this does is to say
On Tue, Feb 8, 2011 at 10:39 AM, C K Kashyap ckkash...@gmail.com wrote:
1) Just use Data.Word.Word8 instead of the second Int in your type sig
for IOArray
2) Use getElems to get a [Word8]
3) Data.ByteString.pack converts a [Word8] into a ByteString
Michael
I am currently using a list of
2011/2/8 Ketil Malde ke...@malde.org:
Gábor Lehel illiss...@gmail.com writes:
Is there any sensible meaning for bangs on return types? I've been
trying to think this through but not necessarily succeeding.
Not knowing Clean in any detail, I've always just thought that a type
signature
On Mon, Feb 7, 2011 at 1:36 PM, Jimbo Massive
jimbo.massive-hask...@xyxyx.org wrote:
On 07/02/2011 11:40, Stephen Tetley wrote:
Interesting point, but excepting that its adding more complexity
Haskell type system, the Clean way of putting strictness information
into the type system seems
On Thu, Feb 3, 2011 at 11:40 PM, Richard O'Keefe o...@cs.otago.ac.nz wrote:
On 4/02/2011, at 10:10 AM, Andrew Coppin wrote:
The important obsevation is this: One tiny, almost insignificant change can
transform a program from taking 50 seconds and 400 MB of RAM into one that
takes 0.02
On Tue, Jan 25, 2011 at 10:20 AM, Ketil Malde ke...@malde.org wrote:
Erik Hesselink hessel...@gmail.com writes:
importing Control.Applicative
main = print = liftM2 (+) readLn (return 3)
[...] line noise
Why not just:
main = print . (+3) = readLn
Or using applicative:
print = (+3) $
The objection to this I recall hearing is that it would make it
possible for different parts of the program to see different instances
for a given type (local instances, effectively), which would have
interesting results. I don't know if there's a way to implement the
feature which avoids this, or
One further idea -- assuming HasBigEndian and HasLittleEndian are
unexported because you don't want people writing new instances -- is
to have something like class HasBigEndianPrivate = HasBigEndian
instead, with the latter exported and the former not, and instances of
each for the same types.
2010/12/24 Henning Thielemann lemm...@henning-thielemann.de:
On Fri, 24 Dec 2010, Gábor Lehel wrote:
One further idea -- assuming HasBigEndian and HasLittleEndian are
unexported because you don't want people writing new instances
Why should people not write further instances? I could write
I agree with the people who want to decouple the dot-syntax from TDNR
itself. To quote myself from the publicly-editable wiki page:
This might be a really dumb question, but is there any reason TDNR
needs to be tied to a new syntax for function application? It seems
strange to me to have one
2010/11/11 Gábor Lehel illiss...@gmail.com:
I agree with the people who want to decouple the dot-syntax from TDNR
itself. To quote myself from the publicly-editable wiki page:
This might be a really dumb question, but is there any reason TDNR
needs to be tied to a new syntax for function
On Thu, Nov 11, 2010 at 12:22 PM, Sjoerd Visscher sjo...@w3future.com wrote:
The equality that people typically expect to hold for Haskell expressions is
that two such expressions are equal if they denote the same thing, as Max
said. Expressions with function type denote mathematical functions,
On Thu, Nov 11, 2010 at 2:15 PM, Jesse Schalken jesseschal...@gmail.com wrote:
2010/11/11 Gábor Lehel illiss...@gmail.com
Obviously there are questions here with regards to the functions which
the to-be-serialized function makes use of -- should they be
serialized along with it? Required
On Thu, Nov 11, 2010 at 2:29 PM, Malcolm Wallace malcolm.wall...@me.com wrote:
I'll just note that LLVM is only
platform independent to a degree. Or rather, I believe the situation
is that it *is* architecture independent, but it doesn't abstract
anything else besides the architecture
In
On Thu, Nov 11, 2010 at 2:59 PM, Miguel Mitrofanov
miguelim...@yandex.ru wrote:
11.11.2010 16:53, Stephen Tetley пишет:
On 11 November 2010 13:10, Lauri Alankol...@iki.fi wrote:
{-# LANGUAGE EmptyDataDecls, MultiParamTypeClasses,
FunctionalDependencies #-}
data PetOwner
data
Well, Template Haskell is what you go to when what you want -can't- be
reasonably expressed with standard GHC Haskell. It's something of a
last resort (at least in my case). Typeclass synonyms can be faked
reasonably well with UndecidableInstances, but if you want to, for
example, automatically
On Mon, Nov 1, 2010 at 6:09 PM, Christopher Done
chrisd...@googlemail.com wrote:
On 1 November 2010 17:53, Paolino paolo.verone...@gmail.com wrote:
I'd like to have a template haskell function that take some constraints and
a class name and write an empty class from those and relative empty
I also vote +1 for lambda-case, and abstain for lambda-if.
I don't think multiple-clause lambdas being desirable should be an
argument against lambda-case. After all, we can also define top-level
functions with either multiple clauses or a single case expression.
Haskell has always followed the
On Wed, Sep 29, 2010 at 11:15 PM, DavidA polyom...@f2s.com wrote:
Ryan Ingram ryani.spam at gmail.com writes:
Haskell doesn't have true type functions; what you are really saying is
instance Monad (\v - Vect k (Monomial v))
Yes, that is exactly what I am trying to say. And since I'm not
On Fri, Sep 17, 2010 at 10:19 PM, Dan Doel dan.d...@gmail.com wrote:
On Friday 17 September 2010 4:04:26 pm Gábor Lehel wrote:
What I would *want* to write is this:
class (Mutable (Thawed a), Frozen (Thawed a) ~ a) = Immutable a where
type Thawed a :: *
thaw :: a - Thawed a
class
Now that the new typechecking awesomeness has been committed to GHC
HEAD, theoretically all of the things one can express with
FunctionalDependencies (bar overlap) should now be expressible with
TypeFamilies as well. This got me to thinking how this might actually
be done.
Here's an example of a
I'm bad at expositions so I'll just lead with the code:
{-# LANGUAGE EmptyDataDecls, TypeFamilies #-}
data True :: *
data False :: *
class TypeValue a where
type ValueTypeOf a :: *
value :: ValueTypeOf a
instance TypeValue True where
type ValueTypeOf True = Bool
value = True
2010/9/8 Miguel Mitrofanov miguelim...@yandex.ru:
On 8 Sep 2010, at 20:01, Gábor Lehel wrote:
I'm bad at expositions so I'll just lead with the code:
{-# LANGUAGE EmptyDataDecls, TypeFamilies #-}
data True :: *
data False :: *
class TypeValue a where
type ValueTypeOf
2010/9/8 Anthony Cowley acow...@seas.upenn.edu:
2010/9/8 Gábor Lehel illiss...@gmail.com:
Oh. Hmm. That makes sense. So I gather there's absolutely no way to
specify which instance you mean, and hence to use `value` as any
concrete type?
Here's one way to indicate which value you
On Mon, Sep 6, 2010 at 5:11 PM, John Lato jwl...@gmail.com wrote:
Message: 20
Date: Sat, 04 Sep 2010 03:40:49 -0400
From: wren ng thornton w...@freegeek.org
Subject: Re: [Haskell-cafe] Restricted type classes
To: Haskell Cafe haskell-cafe@haskell.org
Message-ID: 4c81f801@freegeek.org
On Mon, Sep 6, 2010 at 12:47 PM, Neil Brown nc...@kent.ac.uk wrote:
On 06/09/10 11:23, Johannes Waldmann wrote:
We have overloaded numerical literals (Num.fromInteger)
and we can overload string literals (IsString.fromString),
so how about using list syntax ( [], : )
for anything list-like
On Mon, Sep 6, 2010 at 8:52 PM, Maciej Piechotka uzytkown...@gmail.com wrote:
PS.
data FooBar a = Foo
| Bar
deriving Show
class IsString (FooBar Char) where
toString _ = Foo
class IsList FooBar where
toList _ = Bar
show (1234 :: FooBar Char) == ???
Foo
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