On Wed, Feb 10, 2010 at 16:59, Jason Dusek jason.du...@gmail.com wrote:
I wonder how many people actually write Haskell,
principally or exclusively, at work?
We (typLAB) use Haskell. There's four of us, but only two actually
program Haskell, and not exclusively. We also use Javascript in the
I've used the FileManip package for this. It works fine for my
purposes. I have no idea what the performance is, though, beyond 'good
enough not to care at the moment'.
Erik
On Sun, Aug 22, 2010 at 17:32, Yves Parès limestr...@gmail.com wrote:
Hello,
I would like to recode in Haskell a piece
On Tue, Aug 31, 2010 at 08:24, strejon strej...@yahoo.com wrote:
Hello. I'm using Haskell to write a specification for some software. The
software uses certificates (standard X.509 certificates) and stores user
name information in the Subject's CommonName field.
The X.509 standard doesn't
Yes, if you use template haskell, all top level functions and values
have to be defined before you use them.
Erik
On Tue, Sep 14, 2010 at 18:11, Kevin Jardine kevinjard...@gmail.com wrote:
Hmm - It seems to work if the code is defined before my main function
and not after it.
Does this have
On Sun, Oct 3, 2010 at 14:10, Daniel Fischer daniel.is.fisc...@web.de wrote:
On Sunday 03 October 2010 10:43:24, Henning Thielemann wrote:
On Sun, 3 Oct 2010, Ben Franksen wrote:
Christopher Done wrote:
Consider the following program:
main = putStrLn $ show $ length [undefined ::
On Sat, Oct 16, 2010 at 21:39, Stephen Tetley stephen.tet...@gmail.com wrote:
Hello list
The Monad and Applicative instances for functions are equivalent to
the respective Reader vesions (I use equivalent along the lines of -
operationally the same but without the type distinction / newtype).
On Wed, Oct 27, 2010 at 23:09, Andrew Coppin
andrewcop...@btinternet.com wrote:
On 27/10/2010 05:00 PM, John Lato wrote:
I am somewhat surprised that all capabilities must be ready for GC; I
thought with the parallel GC that wouldn't be necessary. But I don't know
much about GC
On Thu, Oct 28, 2010 at 19:06, Andrew Coppin
andrewcop...@btinternet.com wrote:
On 28/10/2010 09:25 AM, Erik Hesselink wrote:
On Wed, Oct 27, 2010 at 23:09, Andrew Coppin
andrewcop...@btinternet.com wrote:
GHC has a _parallel_ GC implementation, meaning that the GC event runs in
parallel
On Wed, Nov 3, 2010 at 06:49, Tony Morris tonymor...@gmail.com wrote:
I am trying to set up an apache server as an additional source to
hackage for haskell packages.
I have added to my ~/.cabal/config file:
remote-repo: myhackage:http://myhackage/packages
Shouldn't that be:
remote-repo:
On Fri, Nov 12, 2010 at 22:48, Jonathan Geddes
geddes.jonat...@gmail.com wrote:
Records do leave quite a bit to be desired. But does anybody actually have a
concrete alternative proposal yet?
A few months ago I proposed a couple of extensions [1] on -cafe.
[snip]
Consider what this would
On Thu, Nov 18, 2010 at 20:17, Arnaud Bailly arnaud.oq...@gmail.com wrote:
Hello,
I am trying to understand and use the Nat n type defined in the
aforementioned article. Unfortunately, the given code does not compile
properly:
[snip]
instance (Nat n) = Nat (Succ n) where
toInt _ = 1 +
It might be that it both your own package and the dependencies cabal
tries to reinstall all depend on some package P. If the dependencies
are installed depending on P version 1, but to satisfy all
dependencies for your own package, cabal needs them to depend on P
version 2, cabal will reinstall
On Sun, Nov 28, 2010 at 15:59, Jafet jafet.vi...@gmail.com wrote:
But using this instance becomes unwieldy. If using Identity was
transparent, eg. if it was a type synonym
{-# LANGUAGE TypeSynonymInstances #-}
type Identity a = a
instance Applicative Identity where
-- something like
This can be used to call into C code expecting pointer input or output
types to great effect:
wrapperAroundForeignCode :: InputType - IO OutputType
wrapperAroundForeignCode in =
alloca $ \inPtr -
alloca $ outPtr - do
poke inPtr in
c_call inPtr outPtr
peek outPtr
There is also
On Fri, Dec 10, 2010 at 09:33, Simon Peyton-Jones simo...@microsoft.com wrote:
| Interestingly, if I import only Control.Applicative from within GHCi, it
| does not find the instances defined in Control.Monad.Instances although
| this module is imported in Control.Applicative. On the other
I've recently been playing with code for versioning data types. It's
based on happstacks implementation, but uses type families to make it
more modular. I've got some proof of concept code on github [1]. We're
also writing a small library based on this at typLAB, which we'll
probably release as
the same thing.
- jeremy
On Dec 17, 2010, at 3:57 AM, Erik Hesselink wrote:
I've recently been playing with code for versioning data types. It's
based on happstacks implementation, but uses type families to make it
more modular. I've got some proof of concept code on github [1]. We're
also
There is also the hackage 2.0 code [1]. This can be easily
cabal-installed, and added as an extra remote-repo to your
.cabal/config file. We've set this up at typLAB [2], and it's working
great. Cabal upload doesn't support multiple remote repo's, but we've
created a small deployment utility to
We had this problem with a binding to a C++ library (through a C
wrapper). GHCi and cabal didn't work, but ghc --make did. How are you
compiling exactly when you get this error? This is somehow related to
TH, without it, at least cabal also works. I'm not sure about GHCi.
There's also a relevant
On Sun, Jan 2, 2011 at 01:37, Mathijs Kwik bluescreen...@gmail.com wrote:
The original package
http://hackage.haskell.org/packages/archive/reaction-logic/2010.11.17/doc/html/Data-Reactor.html
has a constructor function (mkReactor) with exactly the constraints
I'm after. However, the constraint
This happens because haskel98-1.1.0.0 can't be built with GHC 6.12,
but lacks the proper version constraints to enforce this. If you add
'--constraint=haskell98==1.0.*' to your 'cabal install' command, it
will probably work.
Erik
On Mon, Jan 3, 2011 at 01:08, Matthew Fairtlough
On Tue, Jan 25, 2011 at 05:13, Ryan Ingram ryani.s...@gmail.com wrote:
On Fri, Jan 21, 2011 at 7:58 PM, Casey Hawthorne cas...@istar.ca wrote:
uj supplied this:
About the discussion
putStrLn (readLn + (5 :: Int))..
I'll write it as the following line,
importing Control.Applicative
main =
On Thu, Mar 10, 2011 at 13:34, Lyndon Maydwell maydw...@gmail.com wrote:
Will methods explained here work for boolean expressions?
The convenience of defining using specialised datatypes for
serialising numeric operations comes from Num being a typeclass. This
is not the case for Bool:
On Thu, Mar 17, 2011 at 07:30, C K Kashyap ckkash...@gmail.com wrote:
On Thu, Mar 17, 2011 at 12:30 AM, C K Kashyap ckkash...@gmail.com wrote:
Hi,
I was wondering if this is a defect -
Prelude import Data.Time.Calendar
Prelude Data.Time.Calendar read 2011-10-10 :: Day
interactive:1:1:
I've just tested this, and with GHC 7, cabal chooses QuickCheck 2.4,
whereas with GHC 6.12, it chooses 2.1. If I specify that 6.12 should
choose 2.4 as well, I get the same issue there. This is to be
expected, because I don't see the CPP checks you mentioned in
Test/QuickCheck/Instances.hs in
On Thu, Apr 21, 2011 at 19:25, Rogan Creswick cresw...@gmail.com wrote:
It is safe to do this. You will probably need to specify the full
version, since despite being included in the latest haskell platform,
cabal-install-0.10.x is in the list of things that cabal won't install
automatically.
On Sat, May 7, 2011 at 12:38, Andrew Coppin andrewcop...@btinternet.com wrote:
On 07/05/2011 09:10 AM, Gregory Collins wrote:
Linode. Can't recommend them highly enough.
If Linode is really the cheapest that the Internet has to offer, I'm going
to need to find a job that pays /significantly/
My first thought was to create all of the lookup table lazily, and
create a pure top level binding for it. Something like:
lookupTable :: [Int]
lookupTable = map (\x - unsafePerformIO (create_lookup_table x) `seq` x) [1..]
Then on a calculation you would index into this list and pass the
result
On Fri, May 20, 2011 at 20:39, Gregory Crosswhite
gcr...@phys.washington.edu wrote:
On 5/20/11 8:35 AM, Jeremy O'Donoghue wrote:
I would like to suggest, quite seriously, that the Haskell community try
to come to a consensus about supporting a single Haskell GUI, with a view to
distribution
On Sun, May 22, 2011 at 15:03, Johannes Waldmann
waldm...@imn.htwk-leipzig.de wrote:
I think you should file a bug report with a test case
on GHC.
I am willing to work on this, but I thought I'd go fishing for some
advice first. My program uses: forkIO, STM, and FFI.
I've seen something
On Thu, Jun 9, 2011 at 09:46, DavidA polyom...@f2s.com wrote:
I think that's exactly what the original poster is complaining about. As a
real-
life example, consider
data Graph a = Ord a = G [a] [[a]]
My intention is that whenever I have a Graph a, I want to be able to use the
Ord
On Thu, Jun 9, 2011 at 13:40, Neil Davies semanticphilosop...@gmail.com wrote:
Anyone out there got an elegant solution to being able to fork a haskell
thread and replace its 'stdin' ?
If you don't mind being tied to GHC you can use hDuplicateTo from
GHC.IO.Handle [1]. You can also use dupTo
On Thu, Jun 9, 2011 at 16:40, Donn Cave d...@avvanta.com wrote:
Quoth Erik Hesselink hessel...@gmail.com,
On Thu, Jun 9, 2011 at 13:40, Neil Davies semanticphilosop...@gmail.com
wrote:
Anyone out there got an elegant solution to being able to fork a haskell
thread and replace its 'stdin
On Sat, Jun 25, 2011 at 19:07, Evan Laforge qdun...@gmail.com wrote:
On Sat, Jun 25, 2011 at 9:00 AM, Jens Blanck jens.bla...@gmail.com wrote:
So there's a range of possible Monoid instances for each type,
More for some types than for others. For Maybe there are three:
* always take the
This sound exactly like what attribute grammars, like the system
developed at Utrecht University [1], are useful for.
Erik
[1] http://www.cs.uu.nl/wiki/HUT/AttributeGrammarSystem
On Fri, Jul 1, 2011 at 10:54, Eugene Kirpichov ekirpic...@gmail.com wrote:
Alexey, your definition of mean does not
On Saturday, July 2, 2011, Joe Healy j...@omc-international.com.au wrote:
One of the points I found non obvious were the fact that local time is
just that. There is no knowledge of the actual timezone in the data
type. If you wish to store that, it needs to be stored alongside.
Isn't that what
On Fri, Aug 19, 2011 at 07:23, Henry House hajho...@hajhouse.org wrote:
Does there exist any sample code or other resources on writing a custom
SQL-to-Haskell datatype converter instance for use with HDBC that would be
accessible to someone just starting with Haskell? The reason I need this is
On Fri, Aug 19, 2011 at 14:06, Anupam Jain ajn...@gmail.com wrote:
Hi all,
Suppose I have a compound data type -
data M o = M (String,o)
Now, I can define a function that works for ALL M irrespective of o. For
example -
f :: M o - M o
f (M (s,o)) = M (s++!, o)
I can also use this function
On Fri, Aug 19, 2011 at 16:09, Henry House hajho...@hajhouse.org wrote:
On Friday, 19 August 2011, Erik Hesselink wrote:
Do you really need the precision info about the column, or do you just
need the values at the right precision? Because you get the last thing
already:
Prelude
On Fri, Aug 19, 2011 at 16:53, Henry House hajho...@hajhouse.org wrote:
On Friday, 19 August 2011, Erik Hesselink wrote:
Why exactly do you need the precision information?
Empirical measurements (e.g., sizes of some fields in hectares) are
precise only to a certain level of measurement error
On Friday, August 19, 2011, Brandon Allbery allber...@gmail.com wrote:
On Fri, Aug 19, 2011 at 11:45, Erik Hesselink hessel...@gmail.com wrote:
Note that PostgreSQL also doesn't work with decimals as precision:
postgres=# select 1::decimal(4,2) * 1::decimal(4,2);
?column
2011/9/6 Poprádi Árpád popradi_ar...@freemail.hu:
i have a record with a lot of items used in a state monad.
data BigData = BigData {
data1 :: X
, data2 :: X
-- and so on
}
updateData1 :: X - MonadicEnv()
updateData1 d = do;
On Fri, Sep 9, 2011 at 22:17, Jason Dagit dag...@gmail.com wrote:
On Thu, Sep 8, 2011 at 11:06 PM, Etienne Laurin etie...@atnnn.com wrote:
Hello fellow hackers.
Here is a helpful package I wrote to ease the development of projects
using cabal.
It includes a :cabalset ghci command to set
On Fri, Sep 9, 2011 at 23:41, Vasili I. Galchin vigalc...@gmail.com wrote:
Is there a list of compiler pragmas? Specifically I am looking at how to
specify more than one type variable in a class definition. Also I have
forgotten the meta syntax for specifying a pragma ... some kind of
I use hothasktags [1] which works very well. The only problems are
sometimes with obscure extensions, where haskell-src-exts (which
hothasktags uses) can't parse the file, but that happens very rarely.
Regarding speed: it takes 2-3 s on about 250 source files totaling
about 25000 lines on my
On Tue, Oct 4, 2011 at 20:33, Karel Gardas karel.gar...@centrum.cz wrote:
data PersonType = Person {
id :: Int
, name :: String
, email :: Maybe String
}
deriving (Show, Data, Typeable)
so I have `PersonType' as type constructor and Person as value
On Mon, Oct 10, 2011 at 16:44, Tom Thorne thomas.thorn...@gmail.com wrote:
thanks! I just tried setting -A32M and this seems to fix the parallel GC
problems, I now get a speedup with parallel GC on and performance is the
same as passing -qg. I had tried -H before and it only made things worse,
This is because hSimpleDB doesn't specify version ranges on its
dependencies, when it should. Since hxt changed its module structure
going from 9.0 to 9.1, hSimpleDB doesn't build against 9.0.
You can try to build it by adding '--constraint=hxt==9.0.\*' after
your cabal-install command. You can
On Tue, Nov 8, 2011 at 12:16, Ivan Lazar Miljenovic
ivan.miljeno...@gmail.com wrote:
On 8 November 2011 22:10, Erik Hesselink hessel...@gmail.com wrote:
This is because hSimpleDB doesn't specify version ranges on its
dependencies, when it should. Since hxt changed its module structure
going
On Wed, Nov 16, 2011 at 16:19, Henning Thielemann
lemm...@henning-thielemann.de wrote:
On Wed, 16 Nov 2011, Sean Leather wrote:
(Sent on behalf of Doaitse Swierstra)
Despite some last minute changes to the planning we are happy to announce
that the next
Dutch functional programming day
Hi all,
I've found and solved a problem with mime-mail, and Michael Snoyman
asked me to send a request for feedback to -cafe, so here goes.
In short, the issue is with address headers containing 'special'
(non-ascii) characters. In mime-mail, these are automatically encoded
according to RFC
On Mon, Nov 28, 2011 at 23:55, Willem O dub...@hotmail.com wrote:
And I added this function:
createPoint :: Int - Point
createPoint x = Point x
When I loaded the file containing all this into ghci and executed 'Vector $
map createPoint [1..5]' the result was '(1, 2, 3, 4, 5)' (without the
What is the value of your LANG environment variable? Does it still
give the error if you set it to e.g. en_US.UTF-8?
Erik
On Sun, Dec 4, 2011 at 13:12, dokondr doko...@gmail.com wrote:
Correct url of a bad string:
/base/latest/doc/html/System-IO.html#g:23
On Sun, Dec 4, 2011 at 19:13, dokondr doko...@gmail.com wrote:
Is there any other way to solve this problem without changing LANG
environment variable?
On Sun, Dec 4, 2011 at 8:27 PM, Erik Hesselink hessel...@gmail.com wrote:
What is the value of your
The operator / is an alias for `combine`, which the documentation says:
Combine two paths, if the second path isAbsolute, then it returns the second.
In this case, / is absolute, so it is returned.
If you wish to add a trailing path separator, use `addTrailingPathSeparator`.
Erik
On Mon,
I'm not sure if you really need ClockTime (from old-time), but if you
don't, the types from the 'time' package are all parseable with
`parseTime` [1].
Erik
[1]
http://hackage.haskell.org/packages/archive/time/latest/doc/html/Data-Time-Format.html#v:parseTime
On Thu, Dec 8, 2011 at 14:16,
On Fri, Dec 9, 2011 at 20:45, L Corbijn aspergesoe...@gmail.com wrote:
So I'm interested if there are other libraries that are more suitable
to the task of generating haskell code for library use, and thus
generate 'human readable' exported code (so no TH). I'm also
interested in how other
At Silk [1] we use Haskell for the backend of our web application. The
frontend is Javascript with some functional aspects, and we have a
shallow ruby layer as a website (but not for the actual application).
Erik
[1] http://www.silkapp.com
On Mon, Dec 19, 2011 at 11:04, Ivan Perez
How does this relate to the Maybe lenses in fclabels [1]?
Erik
[1]
http://hackage.haskell.org/packages/archive/fclabels/1.0.4/doc/html/Data-Label-Maybe.html
On Wed, Dec 21, 2011 at 04:54, rocon...@theorem.ca wrote:
Do you miss null references from your old imperative programming days? Wish
On Wed, Dec 21, 2011 at 14:10, Bas van Dijk v.dijk@gmail.com wrote:
On 16 December 2011 16:26, Yves Parès limestr...@gmail.com wrote:
1) What about the First type? Do we {-# DEPRECATE #-} it?
Personnaly, I'm in favor of following the same logic than Int:
Int itself is not a monoid. You
On Wed, Dec 21, 2011 at 16:39, rocon...@theorem.ca wrote:
On Wed, 21 Dec 2011, Erik Hesselink wrote:
How does this relate to the Maybe lenses in fclabels [1]?
Erik
[1]
http://hackage.haskell.org/packages/archive/fclabels/1.0.4/doc/html/Data-Label-Maybe.html
It appears to be somewhere
I would have compose (probably not called '.') read the same way we read
this sentence (and unix pipes) ie left to right.
You can use from Control.Arrow for that if you want.
Erik
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
Type classes are open, so nothing prevents someone from adding an
instance 'C0 T1' and calling 't' with constructor 'B', causing a crash
due to the missing pattern.
Erik
On Thu, Jan 12, 2012 at 21:40, Tom Hawkins tomahawk...@gmail.com wrote:
Let's say I have:
data T0
data T1
data T a where
An interesting use case for this is that while
data Void = Void Void
has infinitely many values (undefined, Void undefined, Void (Void
undefined) etc), the newtype version
newtype Void = Void Void
has only one, bottom. This is a way to define the empty datatype
without extensions.
Erik
I recently ran into this as well. I found this stack overflow question
[1], where Daniel Fischer notes that a proper solution has been found,
and it shouldn't be long until it reaches hackage. That was one and a
half weeks ago.
Erik
[1]
Same workaround as last time works
I.e:
tar -f ~/.cabal/packages/hackage.haskell.org/00-index.tar --delete
bytestring/0.9.2.1
This will only work until the next 'cabal update', right? Does anyone
have a better workaround?
This is the cabal-install shipped with Ubuntu 12.04 (i.e. the
You could use throwTo to raise an exception in the thread you want to
stop. Otherwise, having some variable (IORef, TVar, MVar) that the
long running thread occasionally checks seems like a good solution.
Erik
On Wed, Feb 8, 2012 at 17:04, JP Moresmau jpmores...@gmail.com wrote:
Hello, I'm
Not a single name, but I believe
liftA2 mplus
is the same function, and much shorter (and more general). It uses the
Applicative instance for (a -). Of course, it also works with liftM2.
Erik
On Sun, Feb 19, 2012 at 12:50, Jon Fairbairn jon.fairba...@cl.cam.ac.uk wrote:
This is probably a
However, be aware that aFields, bFields and cFields are now partial
functions that will crash when applied to the wrong constructor. Not
a-okay in my book.
Erik
On Wed, Mar 14, 2012 at 02:24, John Meacham j...@repetae.net wrote:
Why not
data Super
= SuperA {
On Sun, Mar 18, 2012 at 20:28, Simon Hengel s...@typeful.net wrote:
** Not really suer about Mac OS X, but I think it requires Xcode, can
someone confirm this.
Yes, the platform on Mac OS X requires Xcode, which includes gcc.
Erik
___
On Mon, Mar 26, 2012 at 21:24, Antoine Latter aslat...@gmail.com wrote:
On Mon, Mar 26, 2012 at 1:33 PM, Ting Lei tin...@hotmail.com wrote:
Hi,
I was writing a code trying to use MonadPlus to detect some error cases
(representing missing values etc. in pure code). With the Maybe monad, I can
See the relevant trac ticket [1] and the linked mailing list thread.
Erik
[1] http://hackage.haskell.org/trac/ghc/ticket/3339
On Sun, Apr 1, 2012 at 22:58, aditya bhargava bluemangrou...@gmail.com wrote:
After asking this question:
GHCi is defaulting the 'a' in 'Show a' to unit because of the extended
defaulting feature [1] in GHCi. If you turn on
NoMonomorphismRestriction in GHCi, you get the same behavior as in
GHC. If you turn on ExtendedDefaulting in GHC, you get the same
behavior as in GHCi.
Erik
[1]
Hi Rosario,
lhs2tex [1] has the '\eval' command. See section 12 of the manual.
Erik
[1] http://www.andres-loeh.de/lhs2tex/
On Sun, Apr 22, 2012 at 17:59, Rosario Borda rosario.bo...@sinervis.com wrote:
Hi All,
Is there a simple method for embed haskell in other languages, like latex?
An
If you want to get rid of the overlap in your type families, you have
to add an extra argument indicating if the two types are equal. For
this, you need a type family to indicate equality of types. Sadly, the
naive implementation (TEQ x x = True, TEQ x y = False) overlaps and
isn't allowed. I'm
Hi Yves,
The type level numbers have kind Nat, not Int (and so also can't be
negative). They have to be imported from GHC.TypeLits (I'm not sure if
this will change). So the following code works for me in HEAD:
{-# LANGUAGE TypeFamilies, DataKinds #-}
import GHC.TypeLits
type family Something
Do you have a 32bit or 64bit GHC build? That might have something to
do with it, if you're nearing 2^32 (or 2^31) bytes.
Erik
On Fri, Jun 8, 2012 at 2:25 AM, Shaun Jackman sjack...@gmail.com wrote:
Hi,
Data.ByteString.Char8.getContents fails for files 2GB on OS X. Is
there a fix for this?
There is also the 'isevaluated' package (which depends on vacuum, but
seems to do something more involved than your code).
Erik
On Mon, Jul 2, 2012 at 7:40 AM, Chaddaï Fouché chaddai.fou...@gmail.com wrote:
On Mon, Jul 2, 2012 at 5:29 AM, Kazu Yamamoto k...@iij.ad.jp wrote:
Hello,
Are there
We use Jenkins to build our applications. You can have Jenkins slaves
for different platforms. We also use cabal-dev to sandbox the builds,
separating the environments for different executables. This solution
does require one server for every OS you develop for, but I guess you
need that anyway,
On Wed, Jul 18, 2012 at 10:19 AM, Ross Paterson r...@soi.city.ac.uk wrote:
On Wed, Jul 18, 2012 at 06:50:31AM +0100, Andres Löh wrote:
Using --avoid-reinstalls blindly or as a default flag is also
unfortunately not a good idea in general. There are simply too many
cases where installing older
On Wed, Jul 18, 2012 at 11:29 AM, Ross Paterson r...@soi.city.ac.uk wrote:
On Wed, Jul 18, 2012 at 09:35:52AM +0100, Erik Hesselink wrote:
I don't think you can install this package on 7.4. As Andres said, it
requires containers 0.5, but ghc 7.4's base libraries (in this case,
template-haskell
Hi all,
All cabal installs using cabal-install-0.10.2 are currently failing
for us. This is due to the cabal file for HUnit-1.2.5.0, which was
recently uploaded to hackage. The ouput I'm getting from cabal is
just:
Reading available packages...
Resolving dependencies...
cabal: Couldn't read
.
Cheers,
Martijn Schrage -- Oblomov Systems (http://www.oblomov.com)
On 18-07-12 16:26, Erik Hesselink wrote:
Hi all,
All cabal installs using cabal-install-0.10.2 are currently failing
for us. This is due to the cabal file for HUnit-1.2.5.0, which was
recently uploaded to hackage
On Monday, July 23, 2012, Simon Hengel wrote:
On Mon, Jul 23, 2012 at 12:51:32PM -0500, Stephen Paul Weber wrote:
Currently you would have to do the upgrade manually, as `cabal-install
cabal-install` won't work (or alternatively edit your local
On Wed, Aug 1, 2012 at 2:35 AM, Richard Cobbe co...@ccs.neu.edu wrote:
Well, I initially went with String because I didn't want to clutter up my
code with all of the calls to 'pack', especially around string literals.
I'm open to being convinced that it's worth it to switch, though.
For string
Isn't this exactly the problem solved by all the lens packages?
Current popular ones are fclabels [0] and data-lens [1].
[0] http://hackage.haskell.org/package/fclabels
[1] http://hackage.haskell.org/package/data-lens
On Thu, Aug 2, 2012 at 7:34 AM, Jonathan Geddes
geddes.jonat...@gmail.com
On Thu, Aug 2, 2012 at 12:30 PM, Andrew Butterfield
andrew.butterfi...@scss.tcd.ie wrote:
On 2 Aug 2012, at 09:25, Erik Hesselink wrote:
Isn't this exactly the problem solved by all the lens packages?
Current popular ones are fclabels [0] and data-lens [1].
[0] http://hackage.haskell.org
The next version of GHC will have an extension for kind polymorphism.
I'm not sure if it has to be enabled in the module that defines flip
or in the module that uses it, but it might help.
Erik
On Tue, Aug 14, 2012 at 1:38 AM, Tony Morris tonymor...@gmail.com wrote:
I have a data-type that is
I am strongly against this, especially for packages in the platform.
If you fail to specify an upper bound, and I depend on your package,
your dependencies can break my package! For example, say I develop
executable A and I depend on library B == 1.0. Library B depends on
library C = 0.5 (no
Untested, but this should be about right:
osi (Bij f b) = iso (Bij b f)
Erik
On Mon, Aug 20, 2012 at 2:35 PM, Sergey Mironov ier...@gmail.com wrote:
Hi. I'm porting old code, which uses fclabels 0.5. Old fclabels
define Iso typeclass as follows:
class Iso f where
iso :: a :-: b - f a - f
, but if you want to insulate yourself
from package upgrades surely sticking with proven combinations is the way to
go.
Chris
-Original Message-
From: haskell-cafe-boun...@haskell.org
[mailto:haskell-cafe-boun...@haskell.org] On Behalf Of Erik Hesselink
Sent: 20 August 2012 08:33
To: Bryan
On Wed, Aug 22, 2012 at 10:13 PM, Matthew Steele mdste...@alum.mit.edu wrote:
On Aug 22, 2012, at 3:02 PM, Lauri Alanko wrote:
Quoting Matthew Steele mdste...@alum.mit.edu:
{-# LANGUAGE Rank2Types #-}
class FooClass a where ...
foo :: (forall a. (FooClass a) = a - Int) - Bool
I'm not sure if you already have something working, but we have
several in our codebase, all following a similar pattern. For example:
newtype GeoServer a = GeoServer { unGeoServer :: ReaderT
GeoServerState (ServerPartT IO) a }
instance MonadBaseControl IO GeoServer where
newtype StM GeoServer
If you remove the second argument (which you don't use), you have the
function `liftBij` that is in fclabels.
Erik
On Mon, Aug 27, 2012 at 3:55 PM, Sergey Mironov ier...@gmail.com wrote:
Hi. I need map equivalent for Bijection type which is defined in fclabels:
data Bijection (~) a b = Bij {
On Mon, Jul 30, 2012 at 3:33 PM, Ross Paterson r...@soi.city.ac.uk wrote:
On Mon, Jul 30, 2012 at 01:46:24PM +0100, Niklas Broberg wrote:
On Wed, Jul 25, 2012 at 12:22 PM, Ross Paterson r...@soi.city.ac.uk wrote:
As I understand it, the plan is to modify the following packages in
On Mon, Aug 27, 2012 at 7:52 PM, Bryan O'Sullivan b...@serpentine.com wrote:
On Mon, Aug 27, 2012 at 9:57 AM, Erik Hesselink hessel...@gmail.com wrote:
I'm seeing this again, on abstract-deque-0.1.6. Ross, can you fix it
again?
Hang on a second.
The reason you're seeing build breakage
On Thu, Aug 30, 2012 at 7:26 AM, Bryan O'Sullivan b...@serpentine.com wrote:
The FFI now requires constructors to be visible, so CInt has to be
imported as CInt(..).
I think there was already a warning about this one in GHC 7.4, so
there was more time to fix it. Not to say I don't feel your
Note that this does not work if you want to support multiple versions
of GHC, and might not work in general, since
* The hiding of catch is needed for preludes that still have it, since
otherwise it will probably conflict with the one from
Control.Exception.
* Older versions do not have
On Thu, Aug 30, 2012 at 7:24 PM, wren ng thornton w...@freegeek.org wrote:
On 8/30/12 10:26 AM, Erik Hesselink wrote:
* Packages might not work with the new bytestring version, since the
API has breaking changes (although they're supposed to be minor).
For the first two, you need to add some
The way you wrote it, you run the state transformer once for each
request. So the state will be available within a single request, but
not between requests. If you want to persist state between requests,
you can use one the the mutable variables available (TVar or MVar are
good choices; IORefs
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