You can already write this, with only a tiny bit of syntax:
module MyApp where
import Data.Text; import Data.Foldable; import Control.Concurrent
Whether it is good style is another matter, but all compilers will certainly
accept it.
Regards,
Malcolm
On 1 Feb 2017, at 14:18, Vassil
On 24 Oct 2015, at 09:17, Joachim Breitner wrote:
> For example in
>
>>Relevant bindings include
>> syllables :: [(a1, Syllable)]
>> (bound at Derive/Call/India/Pakhawaj.hs:141:16)
>> best_match :: [(a1, Syllable)]
>> -> Maybe (Int, ([(a1, Syllable)],
On 6 Oct 2015, at 17:47, Herbert Valerio Riedel wrote:
>
>> The problem by discussions is that they are done between two groups with
>> quite a difference in experience. On one hand you have people like Bryan,
>> who have considerable contributions to the Haskell ecosystem and much
>>
mation about Haskell, is a powerful
disincentive to continue with it.
Regards,
Malcolm
> On 5 Oct 2015, at 10:05, Malcolm Wallace wrote:
>
>> I am also a strong -1 on small changes that break huge numbers of things for
>> somewhat trivial benefits.
>>
>> Regards,
&
exist. Maybe they do but are too afraid
to speak up (due to corporate policy or whatever).
On Thu, May 7, 2015 at 10:41 PM, Malcolm Wallace malcolm.wall...@me.com
wrote:
I also note that in this discussion, so far not a single person has said that
the cpphs licence would actually
On 8 May 2015, at 00:06, Richard A. O'Keefe wrote:
I think it's important that there be *one*
cpp used by Haskell. fpp is under 4 kSLOC
of C, and surely Haskell can do a lot better.
FWIW, cpphs is about 1600 LoC today.
Regards,
Malcolm
___
licensing issues: perhaps we should simply ask Malcolm
Wallace if he would consider changing the license for the sake of GHC?
Or perhaps he could grant a custom-tailored license to the GHC
project? After all, the project page [1] says: If that's a problem
for you, contact me to make other arrangements
On 20 Jan 2015, at 11:20, Björn Peemöller wrote:
The reason is the usage of foldr, which changed its type from
foldr :: (a - b - b) - b - [a] - b -- GHC 7.8.4
to
foldr :: Foldable t = (a - b - b) - b - t a - b -- GHC 7.10.1
Thus, the use of foldr is now ambiguous. I can fix this by
On 1 Jan 2015, at 13:58, George Colpitts wrote:
Configuring cpphs-1.13...
Building cpphs-1.13...
Warning: cpphs.cabal: Unknown fields: build-depends (line 5)
Could not find module ‘Prelude’
It is a member of the hidden package ‘base-4.8.0.0’.
Perhaps you need to add ‘base’ to
How about doing the honest thing, and withdrawing both packages in ghc-7.10?
Haskell'98 is now 15 years old, and the 2010 standard was never really popular
anyway.
Regards,
Malcolm
On 30 Sep 2014, at 21:21, Austin Seipp aus...@well-typed.com wrote:
Hello developers, users, friends,
I'd
On 25 Apr 2014, at 14:17, Simon Marlow wrote:
The problem we often have is that when you're writing code for a library that
lives deep in the module hierarchy, you end up needing a deep directory
structure, where the top few layers are all empty.
I don't see how this is a problem at all.
Yes, this is a known problem. I intend to put out a fresh version of HaXml
soon to fix it.
Regards,
Malcolm
On 18 Mar 2014, at 15:17, Christian Maeder wrote:
Hi,
under mavericks using the ghc-clang-wrapper (ghc-7.6) or using
ghc-7.8.20140130 I can no longer install the HaXml
If you use cpphs as a library, there is an API called runCpphsReturningSymTab.
Thence you can throw away the actual pre-preprocessed result text, keep only
the symbol table, and lookup whatever macros you wish to find their values. I
suggest you make this into a little code-generator, to
On 27 Aug 2013, at 08:33, Niklas Hambüchen wrote:
@Malcolm, would you mind a change towards throwing an exception that is
different from error so that it can be easily caught, or even better, a
change from
runCpphs :: ... - IO String
to
runCpphs :: ... - IO (Either String
On 6 Aug 2013, at 20:03, Evan Laforge wrote:
I don't know how others like to work, but I like when a compiler bails
early, because I fix errors one at a time, and I search for the
easiest looking ones before worrying about the complicated looking
ones.
With C compilers, it is often the case
On 3 Aug 2013, at 21:03, Jason Dagit wrote:
Another con of using parsec that I forgot to mention in my previous
email is that with Parsec you need to be explicit about backtracking
(use of try). Reasoning about the correct places to put try is not
always easy and parsec doesn't help you with
On 3 Aug 2013, at 02:20, Jason Dagit wrote:
Hi!
Is there any specific reason why GHC is written in a parser GENERATOR
(Happy) and not in MONADIC PARSER COMBINATOR (like parsec)?
Is Happy faster / handles better errors / hase some great features or
anything else?
One reason is that it
On 1 Jul 2013, at 16:07, Vlatko Basic wrote:
I had a (simplified) record
data P = P {
a :: String,
b :: String,
c :: IO String
} deriving (Show, Eq)
but to get automatic deriving of 'Show' and 'Eq' for 'data P' I have created
'newtype IOS' and its 'Show' and 'Eq'
On 28 Jun 2013, at 12:16, AntC wrote:
Thanks Simon, I'm a little puzzled what your worry is.
f r b = r.foo b
With dot-notation baked in (non-orthogonally), f would get the type
f :: (r { foo::Bool }) = r - Bool - Bool
With the orthogonal proposal, f is equivalent to
On 3 Jun 2013, at 20:38, Corentin Dupont wrote:
I'd like to transform a .hs file into a .html file.
The objective is that the .html file, when rendered, looks exactly the same
that the .hs, with the exeption that every function in the code is a link to
its haddock documentation.
Is that
On 29 Apr 2013, at 07:00, Niklas Hambüchen wrote:
I would like to propose the development of source code refactoring tool
that operates on Haskell source code ASTs and lets you formulate rewrite
rules written in Haskell.
Seen this?
http://www.haskell.org/haskellwiki/HaRe
Regards,
On 9 Apr 2013, at 14:46, Sturdy, Ian wrote:
As far as the use of Eq goes, Eq is already enshrined in pattern matching by
pattern matching against literals.
Not true. Pattern-matching literals explicitly avoids any use of Eq.
Demonstration:
data Foo = Foo | Bar
instance Eq Foo where
_
And cpphs strips C comments too. :-)
But seriously, John's use-case is the exact opposite of what you suggest. John
wants to keep the # inside the comment block. You suggest to remove the
comment-block altogether?
When I checked the example with cpphs, it turns out that the # line is
On 8 Apr 2013, at 14:52, Roman Cheplyaka wrote:
In my opinion, it is perfectly valid to have intentional preprocessor
directives inside Haskell comments.
Could you give an example where this is useful?
... macro expansions inside the comments are rather exotic.
{- | Some module
On 1 Apr 2013, at 01:21, Seth Lastname wrote:
Note 2 says, If the first token after a 'where' (say) is not indented more
than the enclosing layout context, then the block must be empty, so empty
braces are inserted.
It seems that, in Note 2, the first token necessarily refers to a lexeme
Doesn't Cabal tend to install library packages under the .cabal folder? So
blowing it away gets rid of the problematic ones. (And everything else.)
On 25 Feb 2013, at 16:56, Brent Yorgey wrote:
On Sun, Feb 24, 2013 at 02:33:55PM +, Niklas Hambüchen wrote:
You are right, my ghc-7.4.2 was
There are lots of Haskell CSV parsers out there. Most have poor
error-reporting, and do not scale to large inputs. I am pleased to announce an
industrial-strength library that is robust, fast, space-efficient, lazy, and
scales to gigantic inputs with no loss of performance.
On 25 Feb 2013, at 11:14, Oliver Charles wrote:
Obvious question: How does this compare to cassava? Especially cassava's
Data.CSV.Incremental module? I specifically ask because you mention that it's
It is lazier, faster, more space-efficient, and more flexible in its
treatment of errors,
Dear Haskell lovers,
The Haskell Prime process for standardisation of new versions of the Haskell
language is at something of an impasse. Since the Haskell 2010 Report was
issued (at the end of 2009), there has been very little momentum to formalise
existing extensions and generalisations,
Dear Haskell lovers,
The Haskell Prime process for standardisation of new versions of the Haskell
language is at something of an impasse. Since the Haskell 2010 Report was
issued (at the end of 2009), there has been very little momentum to formalise
existing extensions and generalisations,
Dear Haskell lovers,
The Haskell Prime process for standardisation of new versions of the Haskell
language is at something of an impasse. Since the Haskell 2010 Report was
issued (at the end of 2009), there has been very little momentum to formalise
existing extensions and generalisations,
On 28/12/2012, at 1:01, Ramana Kumar ram...@member.fsf.org wrote:
On Wed, Dec 12, 2012 at 6:40 PM, Malcolm Wallace malcolm.wall...@me.com
wrote:
There is a mailing list for the members of the language committee:
haskell-2011-commit...@haskell.org.
Hi Malcolm, could you (or someone
On 13 Dec 2012, at 18:40, Michael Snoyman wrote:
I'm not quite certain what to make of:
If you have a commercial use for cpphs, and feel the terms of the (L)GPL
are too onerous, you have the option of distributing unmodified binaries
(only, not sources) under the terms of a different
On 13 Dec 2012, at 10:41, Petr P wrote:
In particular, we can have a BSD package that depends on a LGPL package, and
this is fine for FOSS developers. But for a commercial developer, this can be
a serious issue that is not apparent until one examines *every* transitive
dependency.
This
On 15 Dec 2012, at 16:54, Michael Snoyman wrote:
I would strongly recommend reconsidering the licensing decision of cpphs.
Even if the LICENSE-commercial is sufficient for non-source releases of
software to be protected[1], it introduces a very high overhead for companies
to need to
I confess that I have not had enough free time in the last two years to have
been a good chair for the language committee. (Using Haskell in the real world
is just too absorbing!) I think the next chair should probably be an academic,
who may have more incentive to spend effort on
See also the incremental XML parser in HaXml, described in Partial parsing:
combining choice with commitment, IFL 2006. It has constant space usage (for
some patterns of usage), even with extremely large inputs.
http://www.google.co.uk/url?sa=trct=jq=malcolm+wallace+partial+parsingsource=webcd
Replying by email, since my account on the trac is blocked.
Open Shake implements the finer resolution timestamps needed using the Win32
API. You may want to copy/adapt the code from there:
For the record, it turned out that the key difference between the linux
machines was the fonts packages installed via RPM. The strace utility told me
that the crash happened shortly after cairo/pango attempted (and failed) to
open some font configuration files. After installing some of the
At my workplace, most people who code in Haskell use MS Visual Studio as their
Haskell IDE. :-)
But they don't read Haskell-cafe...
Regards,
Malcolm
On 24 Nov 2012, at 07:28, Dan wrote:
Because I see there are many preferences on what IDE to use for Haskell
I've created a quick survey
On 9 Nov 2012, at 23:04, Michael Mossey wrote:
Couldn't match expected type Text.XML.HaXml.Types.QName with actual type
String.
Poking around, I found this webpage describing an issue with a change to
HaXml that happened after version 1.20.2:
It is kind of ironic that the wide code examples in the blog post are wrapped
at 65 chars by the blog formatting.
Regards,
Malcolm
On 29 Oct 2012, at 11:50, Rustom Mody wrote:
There was a recent discussion on the python list regarding maximum line
length.
It occured to me that
I think you will find that the Original Poster did not ask about ArchHaskell,
but rather about Haskell on the Arch platform. He was completely unaware of
ArchHaskell as a project. This might be a source of some confusion, and help
to explain divergent attitudes.
Regards,
Malcolm
On 29
On 12 Sep 2012, at 16:04, Eric Velten de Melo wrote:
The behaviour I want to achieve is like this: I want the program when
compiled to read from a file, parsing the PGM and at the same time
apply transformations to the entries as they are read and write them
back to another PGM file.
Such
Ralf Laemmel would probably be the world's foremost expert in parsing and
analysing Cobol using functional languages. Try contacting him directly at
uni-koblenz.de
Some of his relevant papers: http://homepages.cwi.nl/~ralf/padl03/
http://homepages.cwi.nl/~ralf/ctp/
On 20 Jul 2012, at 10:08,
On 11 Jun 2012, at 10:38, Dmitry Dzhus wrote:
main = do
g - create
e' - VU.replicateM count $ standard g
return ()
In all likelhood, ghc is spotting that the value e' is not used, and that there
are no side-effects, so it does not do anything at runtime. If you expand the
action
Unless you show us the code, any answers will be guesses in the dark. Does
your program use unsafePerformIO unsafely perhaps? Or a version of a library
that happens to have a known bug?
On 25/05/2012, at 14:33, Mark Conway Wirt markcw...@gmail.com wrote:
I have a piece of Haskell code
On 4 May 2012, at 10:02, Alberto G. Corona wrote:
Restrict (++) String - String - String
that locally would restrict the type within the module.
import qualified Prelude
import Prelude hiding ((++))
(++) :: String - String - String
(++) = Prelude.(++)
no purpose to a completely overlapping category unless it is intended to
relate to an earlier standard (say Haskell 1.4).
I believe all Haskell Reports, even since 1.0, have specified that the language
uses Unicode. If it helps to bring perspective to this discussion, it is my
impression
On 3 Mar 2012, at 04:30, Omari Norman wrote:
On the other hand, I notice that attoparsec and polyparse backtrack by
default, and attoparsec claims to be faster than Parsec (I can't remember if
polyparse makes this claim).
In my benchmarks, polyparse has about the same performance as
On 29 Feb 2012, at 09:53, Antoras wrote:
I updated my GHC version from 7.0.3 to 7.4.1. But after that GHC is unable to
install some required packages.
containers-0.4.2.1 (reinstall) changes: array-0.4.0.0 - 0.3.0.3
binary-0.5.1.0 (reinstall) changes: array-0.4.0.0 - 0.3.0.3
I believe
-1.
I agree with John. There is no point in fiddling with the dots, until we have
real experience with a new records proposal (which can be implemented entirely
without using dot, at least initially).
Regards,
Malcolm
On 10 Feb 2012, at 03:14, John Meacham wrote:
I mean, it is not
On 8/02/2012, at 14:16, Steve Horne sh006d3...@blueyonder.co.uk wrote:
I haven't given a lot of thought to updates.
I very much fail to see the point of replacing prefix function application with
postfix dots, merely for field selection. There are already some imperfect,
but adequate,
Fun in the afternoon, a termly gathering of UK FP people, will be in Oxford
on 28th Feb.
http://sneezy.cs.nott.ac.uk/fun/
On 7/02/2012, at 18:32, Ivan Perez ivanperezdoming...@gmail.com wrote:
Hello,
I recently moved to Kenilworth, Warwickshire, UK, and I'd like
to know if there are
On 29 Jan 2012, at 22:25, Ertugrul Söylemez wrote:
A strict-by-default Haskell comes with the
implication that you can throw away most of the libraries, including the
base library. So yes, a strict-by-default Haskell is very well
possible, but the question is whether you actually want that.
2012/1/22 Данило Глинський abcz2.upr...@gmail.com
What is natural Haskell representation of such enum?
enum TypeMask
{
UNIT,
GAMEOBJECT,
CREATURE_OR_GAMEOBJECT = UNIT | GAMEOBJECT
};
I don't think that definition makes any sense in C, because UNIT is 0, so UNIT
| GAMEOBJECT
On 23 Jan 2012, at 07:01, Erik de Castro Lopo wrote:
/tmp/hspec-0.9.04062/hspec-0.9.0/Setup.lhs:2:10:
Could not find module `System'
It is a member of the hidden package `haskell98-2.0.0.0'.
In ghc-7.2, you cannot use the haskell98 package in conjunction with the base
Sorry to pick on your post in particular Matthew, but I have been seeing a lot
of this on the Haskell lists lately.
I find it completely unreasonable for a reply to a very long post to quote the
entire text, only to add a single line at the bottom (or worse, embedded in the
middle somewhere).
On 12 Jan 2012, at 18:41, Evan Laforge wrote:
Unicode dot (∘) would be optimal, since that's what it's for.
Is ∘ (U+2218 RING OPERATOR)* in Prelude yet? We should propose that.**
However, changing the composition operator from (.) will involve huge
amounts of changes to source code.
The extra parameter i is for information attached to each node of the tree.
As you have correctly guessed, the parser fills in this field with positional
information relating to the original source document, which is useful for
instance if you are validating or checking the original document.
I suggest switching from 'read' to a real parser that can give you proper error
messages. I use Text.Parse from the polyparse package, which is designed to
parse back exactly the format produced by derived Show instances. To derive
the Parse class from your datatypes, the tool DRiFT is handy.
The community Trac hosting server isn't sending email, which Trac requires.
I've submitted several tickets to supp...@community.haskell.org but
gotten no response.
Does anyone maintain that server anymore?
Had the same problem in July. Raised a ticket etc. I don't think there
is anyone
On Windows, it is necessary to add to your PATH variable the bin directory
where the gtk+ DLL lives. Note, this is the C DLL, not the Haskell one
produced by gtk2hs. For instance, on my machine the relevant directory is
C:\workspace\ext\gtk+-2.20\bin. It is quite likely different on yours.
And, amusingly, http://downforeveryoneorjustme.com/ is also down, having
exceeded its Google App Engine quota.
[ But the similarly named .org site still works, and confirms that hackage is
down. ]
Regards,
Malcolm
___
Haskell-Cafe mailing list
On 20 Nov 2011, at 22:20, Ivan Lazar Miljenovic wrote:
On 21 November 2011 03:19, David Fox dds...@gmail.com wrote:
On Fri, Nov 18, 2011 at 1:10 AM, Ertugrul Soeylemez e...@ertes.de wrote:
Ivan Lazar Miljenovic ivan.miljeno...@gmail.com wrote:
Wasn't there talk at one stage of integrating
The problem isn't social pressure to be stable, it's the ambiguity of what
stable means. If Hackage 2 institutes a policy whereby things claiming to
be stable are treated better, then stable is likely to become the new
experimental.
I'd say, rather than rely on social agreement on what
when I am running the program in my terminal on ubuntu its showing me
GHC stack-space overflow: current limit is 536870912 bytes.
Use the `-Ksize' option to increase it.
how can i increase the stack sizePlz help me out
Others have explained how to Use the `-Ksize' option,
Although I still wonder why something so simple in C++ is actually more
verbose and requires less known features in Haskell...What was the design
intent to disallow simple overloading?
The simple C++ overloading you want to add to Haskell, is in fact rather
semantically complex, and it
From compiler/utils/Outputable.lhs
{{{
-- quotes encloses something in single quotes...
-- but it omits them if the thing ends in a single quote
-- so that we don't get `foo''. Instead we just have foo'.
quotes d = SDoc $ \sty -
let pp_d = runSDoc d sty in
case show
On 26 Sep 2011, at 23:14, Arseniy Alekseyev wrote:
Garbage collection takes amortized O(1) per allocation, doesn't it?
No. For Mark-Sweep GC, the cost is proportional to
(H+R) / (H-R)
where H is the total heap size
R is the reachable (i.e. live) heap
This formula amortises the cost of
On 27 Sep 2011, at 11:23, Arseniy Alekseyev wrote:
Malcolm, one should amortize the cost of the collection over the
amount of free space allocated rather than recovered
They are the same thing. You can only allocate from the space that has been
recovered. It is true that generational GC
If this is a _proposal_ to change ghc's non-Report-compatible Data.List
implementation to match the behaviour of the Report implementation, then count
me as a +1.
I think an important convention when it comes to higher order
functions on lists is that to the extent which is possible, the
On 13 Sep 2011, at 18:59, Michael Orlitzky wrote:
Malcolm Wallace and Colin Runciman's ICFP99 paper functioned well as a
tutorial for HaXml when I used it - maybe it is a bit out of date now?
HaXml is hardly a dire case.
The paper is out-of-date, so it's worse than useless: you'll waste
I notice that ghci is loading integer-simple before loading base. This at
least explains why it cannot find a symbol from the base package - it hasn't
been loaded yet. So the question is why does integer-simple use any function
from the base package at all? I'm fairly sure that the dependency
On 19/07/2011, at 0:09, Patrick Browne patrick.bro...@dit.ie wrote:
instance Bird Emperor where
-- No fly method
walk x y = y
instance Penguin Emperor where
-- How can I override the walk method in the instance Penguin?
-- walk x y = x
Why would you want to override the walk method
That just shifts the problem, I think? Now you can no longer comment out the
first line.
If you are using to-end-of-line comments with --, then the likelihood of
noticing a leading ( or { on the line being commented, is much greater than the
likelihood of noticing a trailing comma on the
On 2 Jul 2011, at 22:13, Yitzchak Gale wrote:
[1]http://hackage.haskell.org/package/timezone-series
[2]http://hackage.haskell.org/package/timezone-olson
I'd just like to add that these timezone packages are fantastic. They are
extremely useful if you need accurate conversion between
Once you guys have reached consensus on appropriate revised wording for this
issue, I'll happily apply the changes to the Haskell 2012 Report as a bugfix.
Regards,
Malcolm
___
Haskell-prime mailing list
Haskell-prime@haskell.org
Sure you can.
runningAverage :: Int - [Double] - [Double]
runningAverage n xs = let chunk = take n xs
in (sum chunk / length chunk) : runningAverage (tail xs)
Lazy lists are absolutely ideal for this purpose.
Regards,
Malcolm
On 1 Jul 2011, at 07:33, Eugene Kirpichov
On 22 Jun 2011, at 15:53, Tristan Ravitch wrote:
On Wed, Jun 22, 2011 at 07:48:40AM +0100, Stephen Tetley wrote:
How fast is good old String rather than ByteString?
For lexing, String is a good fit (cheap deconstruction at the head /
front). For your particular case, maybe it loses due to
On 26 Jun 2011, at 01:53, Tony Morris wrote:
Having only had a flirt with Data.Time previously, I assumed
it would be robust like many other haskell libraries.
If, by lack of robustness, you mean that you get runtime errors, then consider
them bugs, and file them with the author/maintainer
On 21 Jun 2011, at 20:53, Elliot Stern wrote:
A tuple is basically an anonymous product type. It's convenient to not have
to spend the time making a named product type, because product types are so
obviously useful.
Is there any reason why Haskell doesn't have anonymous sum types? If
On 18 Jun 2011, at 20:19, Jack Henahan wrote:
but the dev would either be forced into Hugs, or they'd have to implement a
more portable GHC. Does such a thing exist already?
Just as a point of interest, the original nhc compiler was original written for
an ARM architecture machine (Acorn
As one of the few people who has habitually used Haskell'98 wherever possible,
I favour plan A. As I recently discovered, in ghc 7 it is already very fragile
to attempt to depend on both the base and haskell98 packages simultaneously.
In most cases it simply doesn't work. Removing those few
| Is there a policy that only a proposal's owner can modify the wiki
| page? Or that you have to be a member of the Haskell' committee?
I'm not sure. Malcolm Wallace is chair at the moment; I'm ccing him.
I have no idea: I neither set up the wiki, nor do I have any interesting admin
On 10 Jun 2011, at 02:15, Manuel M T Chakravarty wrote:
Anybody who is halfway serious about developing software on a Mac will have
Xcode installed anyway.
As the original poster clarified, the motivating use-case is education
(specifically a class of 12-13 year olds.) These are not
http://hackage.haskell.org/trac/PolyFunViz/wiki/IEEEVisCode
talks about the code being available through darcs but I can't seem to put my
hands on the http address I would need to pull the code.
This is all relating to the paper, Huge Data but Small Programs:
Visualization Design via
Curious observation:
Object languageType language
OO (C++)functional
functional (Haskell)logical
It makes me wonder what comes next...
To be more accurate, it was Functional Dependencies that introduced a logic
programming language to the type
More seriously, the influence of Haskell over F# (and even Python) is
undoubted, but do you really think Haskell influenced Java Generics? (IMHO
they were more inspired from C++ templates)
(That is a question, not an assertion).
Phil Wadler had a hand in designing both Haskell and Java
data Bar f a = Foo f = Bar {bar :: f a}
The class context on the data constructor buys you nothing extra in terms of
expressivity in the language. All it does is force you to repeat the context
on every function that uses the datatype. For this reason, the language
committee has decided
On 6 Jun 2011, at 13:49, Lyndon Maydwell wrote:
I would be fantastic if XCode wasn't a dependency. ...
Not to detract at all from the work of the wonderful GHC and Haskell
Platform contributors in any way. For me it would just make it that
much easier to convince mac-using friends to give
it won't be a pleasant choice to fork over a good chunk of money to
Apple for the use of free software that they didn't develop.
Whilst I acknowledge your painful situation, I'd like to rebut the idea that
Apple stole someone else's free software and are selling it on. In fact, Apple
On 6 Jun 2011, at 13:49, Lyndon Maydwell wrote:
I would be fantastic if XCode wasn't a dependency. ...
Not to detract at all from the work of the wonderful GHC and Haskell
Platform contributors in any way. For me it would just make it that
much easier to convince mac-using friends to give
On 5/06/2011, at 13:12, 吴兴博 wux...@gmail.com wrote:
1) I'm using Haskell platform 2011.2 on windows (7). Every several
days, ghci will crash with no messages. even when I'm just typing with
text buffer, without an 'enter'. I got nothing after the crash, not
even an exception code, don't even
-- followed by a symbol does not start a comment, thus for example, haddock
declarations must begin with -- |, and not --|.
What might --| mean, if not a comment? It doesn't seem possible to define it
as an operator.
GHCi, at least, allows it.
Prelude let (--|) = (+)
Prelude 1 --| 2
I tried gnuplot:
Demo.hs:25:18:
Could not find module `Paths_gnuplot':
Use -v to see a list of the files searched for.
Failed, modules loaded: none.
Prelude Graphics.Gnuplot.Simple
Where to get `Paths_gnuplot': module?
$ cd gnuplot-0.4.2
$ cabal install # this generates
instance (Monad m, MonadPlus m) = Monoid (Stream m a) where
mempty = Chunks mempty
mappend (Chunks xs) (Chunks ys) = Chunks (xs `mappend` ys)
mappend _ _ = EOF
Iteratee.hs:28:25:
No instance for (Monoid (m a))
arising from a use of `mempty'
There is a clue
On 23 May 2011, at 17:20, michael rice wrote:
What's the best way to end up with a list composed of only the Just values,
no Nothings?
Go to haskell.org/hoogle
Type in [Maybe a] - [a]
Click on first result.
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On 23 May 2011, at 17:20, michael rice wrote:
What's the best way to end up with a list composed of only the Just values,
no Nothings?
Alternatively,
[ x | Just x - originals ]
It also occurs to me that perhaps you still want the Just constructors.
[ Just x | Just x -
On 15 May 2011, at 15:35, Immanuel Normann wrote:
Why is it so complicated to install the base package?
You cannot upgrade the base package that comes with ghc.
It's a bad design, but there we go.
Regards,
Malcolm
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