> Perhaps, this is madness, but I wanted to read other opinions on this topic.
Packages already have multiple tags, right? So how about a search box
that uses ANDed tags (in addition to description etc), and a browsing
interface where you can see tags of packages matching the current
search, and
Here's a different approach:
If you just want to make the typechecker distinguish between some
values but still have some functions that don't care what "subtype"
they are, you can use phantom types:
data Obj x = Obj X Y Z
data BlogObj
type Blog = Obj BlogObj
data CommentObj
type Comment = Obj
Lately I've been spending more and more time trying to figure out how
to resolve circular import problems. I add some new data type and
suddenly someone has a new dependency and now the modules are
circular. The usual solution is to move the mutually dependent
definitions into the same module, bu
On Sat, Aug 28, 2010 at 12:22 PM, Carter Schonwald
wrote:
> i believe that a valid idiom is to define a class C that has no functions,
> but requires any instance to also be of type classes A and B, so that you
> can write: C a => blah
> rather than (A a,B a)=> blah, though I don't know how o
On Sat, Aug 21, 2010 at 6:52 PM, Michael D. Adams wrote:
> Could you be more specific about what operations you want and their
> properties (e.g. performance laziness, etc.)? For example, do you
> need to be able to cons onto the front or is the list generated once
> and never consed onto? Do yo
> I wonder... How many people are actually working on Cabal?
>
> When I first started using Haskell, I got the impression that there were
> hundreds, maybe even thousands, of developers working on GHC. (After all,
> how else could you write such a huge codebase in less than two centuries?)
> But no
> However, I haven't thought about how operations such as 'cons' and
> 'tail' would be implemented =). OP just asked about indexing ;-).
Hah, serves me right I suppose. I figured the promise of some type
fanciness would be catnip to some well-typed cats out there, but your
implementation is even
Is there a data type that's spine lazy like a list, but can be seeked (sought?)
efficiently? IntMap and Sequence are spine strict so if you take the head
element all the elements are forced even if their contents are not. E.g.,
'Sequence.index (Sequence.fromList [0..]) 0' will diverge, but obviou
> It sounds to me like your life would be a lot easier if you knew about
> cabal-install's root-cmd configuration parameter! Open your
> .cabal/config file and uncomment and set:
>
> root-cmd: sudo
I didn't know about this either. As an aside, is the cabal config
file documented at all? I haven'
On Fri, Aug 13, 2010 at 6:41 PM, Brandon S Allbery KF8NH
wrote:
> -BEGIN PGP SIGNED MESSAGE-
> Hash: SHA1
>
> On 8/13/10 16:37 , Kevin Jardine wrote:
>> Surely efficient Unicode text should always be the default? And if the
>
> Efficient for what? The most efficient Unicode representation
This is something I've wanted for a long time, but I always intended
to just submit a patch since it would be trivial, but maybe other
people have an opinion about it too:
I've always wanted a button to collapse or maybe toggle all expanded
branches. Once a library gets large, it's easier to navi
>> Just think of "unsafe" in relation to "unsafeIndex" or something.
>> It's faster, but you have to be sure the index is in bounds.
> Yes, but the whole reason to use "unsafe" is to get higher performance
> at the cost of safety. If the result of calling an "unsafe" foreign
> function is that you
On Tue, Aug 3, 2010 at 3:06 PM, Gregory Crosswhite
wrote:
> But you've got it backwards: if the function I am calling can call back
> into Haskell (i.e., is marked as "safe"), then GHC *doesn't* block the
> world, but if the function I am calling will never call back into Haskell
> (i.e., is mark
> I've always thought that being able to write:
>
>> catMaybes :: [Maybe a] -> [a]
>> catMaybes xs = [ x | Just x <- xs ]
>
> is really cool, which relies on:
>
>> fail _ = []
>
> being in the Monad instance for List.
Really? I thought that's just a feature of list comprehensions. List
comps are
On Mon, Jul 26, 2010 at 12:54 PM, Kevin Jardine wrote:
> On Jul 26, 6:45 pm, Nick Bowler wrote:
>
>> Since when do mailing lists not have threading? Web forums with proper
>> support for threading seem to be few and far apart.
>
> Most of the email clients I'm familiar with don't support threade
On Fri, Jul 16, 2010 at 11:21 AM, Don Stewart wrote:
> Generally, in Erlang or Haskell, the semantics we use is to keep
> all the old code in memory, for the case of closures and thunks that
> point back into that code.
>
> You can imagine a fine-grained semantics where as each top level
> functi
> As I say, every time I've tried to do this, I end up writing a function to
> "run this stuff", and it typically takes a few hours to reach the point
> where it type-checks.
It took me a while the first time, but then I just learned the pattern
and I do it that way every time. Here's my pattern:
> I'm interested in situations where you think fundeps work and type families
> don't. Reason: no one knows how to make fundeps work cleanly with local type
> constraints (such as GADTs).
>
> If you think you have such as case, do send me a test case.
Well, from looking at the documentation, it
> I think your problem here is that there's no mention of `a' on the
> left-hand size of from_val's type signature; you either need to use
> MPTC+fundep to associate what result is compared to a, or else use a
> phantom type parameter of Val to make it "data Val result a = ..." and
> then "from_val
I have a parameterized data type:
> data Val result = VNum Double | VThunk (SomeMonad result)
> type Environ result = Map Symbol (Val result)
I have a class to make it easier to typecheck Vals:
> class Typecheck a where
> from_val :: Val result -> Maybe a
>
> instance Typecheck Double where
>
>> So how does one get off haskell? Are there people in similar situations
>> that have managed? How did you do it?
I used to get annoyed about all the java boilerplate and awkwardness.
But then I learned that if I relax and stop thinking so much about the
aesthetics of what I'm writing, I can jus
> How should I work around that. I could use two different "name" function, but
> I don't like this. Would I have to define a typeclass "namedFunction" which
> all have a "name" function?
How about a "named" type:
data Named a = Named {
val_of :: a,
name_of :: String
}
You can put it in Fu
On Thu, Jun 3, 2010 at 3:05 PM, Don Stewart wrote:
> wasserman.louis:
>> What, if anything, stands in the way of parallelizing Cabal installs, make -j
>> style?
>
> Parallelizing ghc --make
>
> http://vimeo.com/6572966
Something I wondered from watching that talk, rather than trying to
make gh
> [1] By co I mean Ruby, Python, Perl and others. There are no so many
> languages that do recognize the difference.
% python -Q new
Python 2.4.6 (#1, Aug 3 2009, 17:05:16)
[GCC 4.0.1 (Apple Inc. build 5490)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
10 / 3
> So, sadly, I think your chances of shipping your a title written in Haskell
> on the iPhone are shot to hell.
+1 for the android version.
Disclaimer: biased google employee
:P
Unfortunately then you get another cockamamie restriction in the whole
JVM vs. tail calls thing... but if you can ge
> Hi Evan, hasn't EHC had something like this for a while with 'type
> class directives'?
I dunno, I don't even know what ehc is. Is it this?
http://www.cs.uu.nl/wiki/Ehc/WebHome
I turned up a paper that mentioned type class directives, but I
haven't read it yet. In any case, the EHC page says
> I wonder: Of cases where overload resolution via available instances
> would be reasonable, how many would also make sense as a closed type
> class? By comparison, it seems that many uses of OverlappingInstances
> are really just trying to express a closed type class with one or more
> default in
> On the one hand, this is doable with the GHC API. On the other, that more
> or less means your program contains what amounts to a full copy of GHC.
And the result is that your binary will grow by 35mb, add a few
seconds to launch time, the first expression will take 3 or 4 seconds
to evaluate,
On Tue, May 4, 2010 at 1:23 PM, David Waern wrote:
> 2010/5/4 Sean Leather :
>> Somewhat OT, but is there a place where we can request/review features in
>> the new HTML presentation of Haddock. Are there any mockups of what the
>> pages might look like? I've had some ideas pop around my head ever
> 3) Configuration
>
> I haven't looked at this yet but I suspect people will not want
> another configuration file in their projects. Perhaps you could
> propose some kind of Cabal integration instead.
It would be a shame if I had to figure out how to write a cabal file
for my project and replace
Ohh, and the other issue I had was that setting iskeyword causes 'w'
to skip over '.'s. This causes trouble for me because I'm used to
using 'w' to skip between components of the symbol and 'W' to skip it
entirely. Is there a workaround you use, maybe a better way to
navigate?
___
On Thu, Apr 1, 2010 at 1:46 PM, Luke Palmer wrote:
> Hi,
>
> I'd like to draw attention to a little script I wrote. I tend to use
> qualified imports and short names like "new" and "filter". This makes
> hasktags pretty much useless, since it basically just guesses which
> one to go to. hothask
This may not be helpful for you, but when I did GUI stuff with haskell
I wrote the GUI part in c++ with fltk, exposed a medium-level api
specific to that gui, and then call that api through the FFI. This is
sort of like the web browser + backend thing, except switch c++ and
fltk for javascript and
> The difference (in work) between map Wrapped and conv is the difference
> between map id and id :: [a] -> [a]. In the absence of any fusion/rewrite
> rules, the former breaks down a list, and builds up a new one with exactly the
> same elements (or, every element x becomes an id x thunk, perhaps)
> real :: Parser String
> real = do
> d <- decimal
> f <- option "" $ do
> p <- char '.'
> n <- many1 digit
> return $ p : n
Just to throw two bits in here, this is the only style that doesn't
require leaning on the space bar and squinting to line things up,
doesn't require any fancy ed
On Wed, Feb 24, 2010 at 3:10 PM, Ivan Miljenovic
wrote:
> On 24 February 2010 20:17, Magnus Therning wrote:
>> I often find that I do want an export list to reduce clutter in the
>> finished code, but for testing I'd like to expose everything in a
>> module. Is there a nice way to deal with this
On Thu, Feb 18, 2010 at 5:22 PM, Leon Smith wrote:
> On Thu, Feb 18, 2010 at 3:07 AM, Evan Laforge wrote:
>> BTW, I notice that your merges, like mine, are left-biased. This is a
>> useful property (my callers require it), and doesn't seem to cost
>> anything to imp
BTW, I notice that your merges, like mine, are left-biased. This is a
useful property (my callers require it), and doesn't seem to cost
anything to implement, so maybe you could commit to it in the
documentation?
By left-biased I mean that when elements compare equal, pick the
leftmost one, e.g.
By purest coincidence I just wrote the exact same function (the simple
mergeAll', not the VIP one). Well, extensionally the same...
intensionally mine is 32 complicated lines and equivalent to the 3
line mergeAll'. I even thought of short solution by thinking that
pulling the first element destro
> I'm no fan of (!!) on lists or other containers where it isn't O(1),
> but lookup/member are a bit more promising. However are there any
> useful derived operations or constructions that can be defined only in
> terms of a Lookup type class? For comparison, Monoid has mconcat as a
> derived op an
On Sun, Feb 14, 2010 at 2:22 PM, Stephen Tetley
wrote:
> On 14 February 2010 22:11, Evan Laforge wrote:
>
>> There's still no consensus on typeclasses for collections, so these
>> are all separate functions. Has anyone taken a shot at a set of
>> AT-using classes
>> Finally, it is the array subscript operator:
>>
>> let x = arr ! 10
>
> Shouldn't this be
>
> let x = arr !! 10
!! is the list subscript. Look in Data.Array.IArray for (!). Or Data.Map.
There's still no consensus on typeclasses for collections, so these
are all separate functions. Has anyon
On Thu, Feb 11, 2010 at 1:49 PM, John Van Enk wrote:
> Perhaps just defining the interface and demonstrating that different RTS's
> are swappable would be enough?
I read a paper by (I think) a Simon, in which he described a haskell
RTS. It would make it easier to experiment with GC, scheduling,
> It's an improvement. It's still not pretty, but I guess that's as good as
> it's going to get...
>
> Maybe this is an instance of Haskell trying to tell me "if you need to write
> a 20-line do-block in the middle of your function, you're doing it wrong".
20 lines is a lot, but I have smaller one
On Thu, Jan 14, 2010 at 5:19 AM, Ozgur Akgun wrote:
> Can someone give an example of a "reasonable" function that never uses one
> of its parameters, and justify the existence of that parameter in this case,
> please?
As I mentioned, this is not only about parameters, but about type
variables. F
>> Unicode identifiers are fun but this is a good point. The line has
>> to be somewhere, so it might as well be in the historical position
>> unless there are widely agreed on benefits to moving it.
>
> I have already crossed that line:
Ha, well haskell programmers wouldn't be haskell programmer
Wow, that's kind of cute:
{-# LANGUAGE UnicodeSyntax #-}
(＊) = (*)
(／) = (/)
公式 高 中 低=高＊中＊低／整數
整數 = 123
Oddly, if I change the order of these definitions I get syntax errors.
Very mysterious. Nice how it knows that ＊ is a symbol, but I'm not
sure how I'm supposed to name a type. It certainly s
> Now, in Haskell we have type inference, which is "The Good Thing" as
> it allows to "validate" your program at compile time. Hence, the idea
> coming up to my mind is that type inference actually forbids a
> type-directed resolution of names as in C++ or Java.
>
> Is this correct?
There is a pro
>> Isn't that what we have here? a function of type (a -> A -> B) cannot
>> use the first argument in any meaningful way.
>
> I think, he wants to document that the type variable 'a' is not used in the
> *type*.
Yeah, that's the idea, sorry if I wasn't clear.
In the case of const, I might write
Occasionally I have a function with an unused argument, whose type I
don't want to restrict. Thus:
f :: _unused -> A -> B
f _ a = b
Since it's a little unusual, I try to make it clear that the type is
intentionally ignored. But it makes me wonder, would it make sense to
allow _ as a type variab
> What do you mean by "completely abort"? Couldn't it simply raise an
> exception that could be handled in main?
Yeah, that's what I meant by complete abort. You don't get to save
the work you did get done. You could checkpoint progress, but of
course that's an impure operation.
> My question is this: how do I change my program to make StringMap a
> lazily-loaded structure based on getStringMapValue without changing f?
You can't, because 'f' has a pure signature, but you want it to run
network operations, which are not pure.
You could say it's logically pure if you guara
I used to refer to them as dromedaryCase and BactrianCase, but the
names never caught on :(
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
> So my biggest reservation is if I can even call my branch the same
> parser as Parsec.
Maybe we could go the way regexes: say "parsec" is an API, and allow
multiple backends with different characteristics as long as they
basically implement that API. In practice, a lot of parser combinator
libr
So far, this new release has let me remove:
- The new "Import of xyz is redundant" warning pointed out tons of cruft in my
imports: 117 of them! Apparently it's better than the 6.10 algorithm. It's
amazing how much cruft builds up in import lists over time even with -Wall.
One issue is that I c
Ohh, it's for *patches*, not just warnings. Never mind then...
On Mon, Dec 14, 2009 at 4:08 PM, Evan Laforge wrote:
> I noticed noise on the cabal list about updating for 6.12, and that it
> was nontrivial.
>
> Also, haddock won't compile with 6.12, and I couldn't
I noticed noise on the cabal list about updating for 6.12, and that it
was nontrivial.
Also, haddock won't compile with 6.12, and I couldn't find anything
about a new release.
If someone else doesn't get there first, I'll add them to the wiki tonight.
_
On Wed, Dec 9, 2009 at 3:26 PM, John D. Earle wrote:
> The problem that I see with elision resulting in juxtaposition is that it
> would alter the layout. Each line would not have the same number of
> characters before and after the makeover. Visual appearance would also be
> altered. Replacing hy
On Fri, Dec 4, 2009 at 1:09 PM, John MacFarlane wrote:
>> On Mon, Nov 23, 2009 at 12:29 PM, Antoine Latter wrote:
>
>> I finally had some time to test it. After running it multiple times
>> (of course, it would be nice to use criterion here), I'm getting
>> numbers in this neighborhood:
>>
>
> I
> I'd just like to point out or reiterate the odd rise in trolling and the
> recent announcements of haskell-2010...
Just wait until haskell-2012 is announced with nonexistential aka
eschatological types spelled "notany a. World".
It evaluates to a new form of bottom that blackholes the entire wo
> I will take an example:
>
> f x y= x+y
>
> The program ask the user to enter two numbers and print the sum. If the
> user enter "1 2" "f 1 2=3" is stored and a gargage collector is used to
> remove this dandling expression later ?
> If the user enter again "1 2", ghc search in dandling results to
This is only peripherally related, but I also have a lot of list
functions that can possibly be an error, but usually processing can
continue. So they tend to return [Either Error Result]. I have
another function thus:
-- A foldr version is not lazy enough and overflows the stack.
partition_eith
The proposal has this sentence, apparently in reference to using
qualified imports: "This is sufficient, but it is just sufficiently
inconvenient that people don't use it much." Does this mean qualified
imports? I use them exclusively, and I'd love it if everyone else
used them too.
Anyway, a f
e a huge win for GHC, at least on
> linux. Does GHC on windows use GNU ld?
Improving GNU ld would be a huge win in a lot of places, and the fact
that no one has done it (excepting gold of course) goes to show it's a
lot easier said than done!
On Thu, Nov 12, 2009 at 4:58 PM, Richard O
On Wed, Nov 11, 2009 at 11:22 PM, David Virebayre
wrote:
> On Thu, Nov 12, 2009 at 7:18 AM, Bulat Ziganshin
> wrote:
>>
>> Hello Evan,
>>
>> Thursday, November 12, 2009, 4:02:17 AM, you wrote:
>>
>> > Recently the "go" language was announced at golang.org. There's not a
>> > lot in there to make
Recently the "go" language was announced at golang.org. There's not a
lot in there to make a haskeller envious, except one real big one:
compilation speed. The go compiler is wonderfully speedy.
Anyone have any tips for speeding up ghc? Not using -O2 helps a lot.
I spend a lot of time linking (
> And this is confusing to those of us who are not compiler experts.
>
> Haskell knows when I have a list of Doubles, you know, because it's strongly
> typed.
>
> Then it proceeds to box them. Huh ?
>
> The laziness thing has many example od _reducing_ efficiency, but there
> seems to be a real lac
> So what's the deal with Clean? Why is it preferable to Haskell? Why is it not?
Purely from glancing through the language reference, two things that
it looks like clean has that I would love to have in haskell are
better records and better arrays. The records don't implement any of
the fancy sub
On Mon, Nov 2, 2009 at 5:29 PM, Magicloud Magiclouds
wrote:
> Hi,
> Say I have something like this:
> [ Record { item = "A1", value = "0" }
> , Record { item = "B1", value = "13" }
> , Record { item = "A2", value = "2" }
> , Record { item = "B2", value = "10" } ]
> How to convert it into:
> [ XX
On Tue, Oct 27, 2009 at 10:08 AM, Kim-Ee Yeoh wrote:
>
> Hi Brent,
>
> Re: '"if" expressions, not statements' is an elegant clarification, one
> definitely for the haskellwiki, if not there already.
>
> Just for completeness' sake, bottom is a value for any expression.
> Wouldn't making the else c
On Sun, Oct 18, 2009 at 11:50 PM, zaxis wrote:
>
> The original code is:
>
> winSSQ count noRed noBlue = do
> let yesRed = [1..33] \\ noRed
> let yesBlue = [1..16] \\ noBlue
> bracket (openFile "ssqNum.txt" WriteMode) (hClose) (\hd1 -> pickSSQ
> count yesRed yesBlue hd1)
>
> It works ver
Sorry! Never mind all that. I just stumbled across
http://hackage.haskell.org/trac/ghc/wiki/ExplicitCallStack
*sigh*
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
I forgot to mention this, but control-monad-exception reminded me:
Is there any interest in a way for ghc to report source locations? I
have a preprocessor that basically works and is really useful but also
awkward and not scalable. control-monad-exception has TH which is
more scalable but requi
On Thu, Sep 24, 2009 at 8:11 AM, pepe wrote:
> Exceptions in the ErrorT monad are not compositional.
> It's the first time I see the approach of stacking
> several ErrorT monads. It seems slightly better than
> having a 'global' exception type, although the explicit
> lifting looks quite painful.
I don't have an especially deep understanding of monad transformers...
basically, I asked around (thanks #haskell!) and struggled and with helpful
advice came up with something that seemed to work for me, only now I'm having
trouble. What I'm trying to do is hardly revolutionary or even advanced,
> It would be so much better if we could discuss a _real_
> example.
Or implement one. Unlike some proposals, this could be implemented
with a preprocessor and -F -pgmF, right? As far as the parsing job, I
don't know how hard this would be to plug into the haskell parsing
library, but in case it
> if I understand you correctly, all libraries that software I write depends
> on, directly or indirectly, must be free of namespace conflicts. Is that
> correct?
Well, it may be more accurate to say that class instances have no
namespaces, and are all implicitly global. When you import a module
On Fri, Sep 11, 2009 at 6:10 AM, Edward Kmett wrote:
> Unfortunately, the instance of Monad for Either a is somewhat misguided in
> Haskell.
>
> There is a spurious restraint that the Left value in your Either be a member
> of some Error class, which was brought about by the deletion of MonadZero
Is there any particular reason to not move the instance to the
prelude? A module was failing when imported from one place and ok
when imported from another, so I spent a frustrating 10 minutes
searching for the instance. I couldn't find a way to search haddock
for instances (not even grep on the
> | Even is suggesting that instead of reporting an error, in the second
> | case we could use the translation:
> |
> | f (A.A { A.a }) = a --> f (A.A { A.a = a })
> |
> | (i.e., when punning occurs with a qualified name, use just the
> | unqualified part of the name in the pattern)
>
> Yes,
One issue I have which I haven't seen anyone mention is that it's not
useful with qualified names, by which I mean always importing
qualified. Of course if you have no problem always using qualified
names, the problem this extension is solving doesn't exist. Though I
do like short names I'm not t
On Fri, Jul 24, 2009 at 4:48 PM, Iavor Diatchki wrote:
> Hello,
> I think that Even refers to an example like this:
...
Yeah, that's exactly what I meant, sorry if it wasn't clear initially.
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://w
Record punning is not all that useful with qualified module names. If
I write '(M.Record { M.rec_x })' it says " Qualified variable in
pattern" and if I write '(M.Record { rec_x })' it says 'Not in scope:
`rec_x''. Could it be this extension be further extended slightly so
that 'f (M.Record { M.r
On Wed, Feb 11, 2009 at 9:34 PM, Alistair Bayley wrote:
> 2009/2/11 Cristiano Paris :
>> I wonder whether this can be done in Haskell (see muleherd's comment):
>>
>> http://www.reddit.com/r/programming/comments/7wi7s/how_continuationbased_web_frameworks_work/
>
> WASH did/does something similar. Y
On Mon, Feb 9, 2009 at 2:57 PM, Jared Updike wrote:
> I would like to enumerate a subset of keys in a Map satisfying \ key
>>= key1 && key <= key2 but in the expected, reasonable amount of time
> (e.g. < O(log(n)) + O(m) for n total keys and m keys in the subset).
> (Or key > key1 and/or key < key
> Conal> As Meister Eckhart said, "Only the hand that erases can write the
> Conal> true thing."
>
> Nicely said...
>
> I'm sure you're not the only one desiring to write GUI in "genuinely
> functional" toolkit, but, being realistic and considering how many people
> are working on bindings for thos
> Nice. Good solution. ``imperative style'' is not a bad idea when I'm
> not used to the ``pure functional style''
>
> E.g.
>
> filename <- return $ combine filename "Makefile"
>
> Similar to the other imperative language
>
> filename = joinPath(filename,"Makefile")
I wouldn't consider it
2009/1/6 Luke Palmer :
> 2009/1/6 Wang, Chunye (NSN - CN/Beijing)
> Dear haskeller,
>>
>>
>> Can I destructive rebind a local variable like this
>>
>> import System.Directory
>> test filename = do
>> is_dir <- doesDirectoryExist filename
>> let filename = if not is_dir then filename else f
>> So it *looks* like there's only one list created in 'lvl1', but I
>> can't see where it's turning into a tuple, and I don't understand the
>> ' = : ' stuff,
>
> You're reading it wrong. : is a name.
> It's lvl5 = (:) @ Char a2 ([] @ Char) where @ is type application
> (instantiation). Triming t
> Although equal? treats the two as the *same*, they're different lists
> because if we modify one (e.g by set-car!) the other won't be affected.
>
> So here comes another question: when we say a function always give the
> same output for the same input, what the *same* means here? ídentity
> or eq
> In the short term, yes. But it's my opinion that most anything that's
> a win for ease of modification is a win for performance in the long
> run, if it gets more people writing code.
Also agreed, in theory. The language is definitely also in line with
this philosophy. In practice, though, it
> It's always possible to decompose the final program down into one that
> could be based on locks. But this is often at the cost of
> maintainability; the code becomes one mess of spaghetti locking in
> order to maintain whatever invariants need to be maintained to prevent
> deadlock and compose
On Mon, Dec 29, 2008 at 1:15 PM, Ryan Ingram wrote:
> Both readTVar and writeTVar are worse than O(1); they have to look up
> the TVar in the transaction log to see if you have made local changes
> to it.
>
> Right now it looks like that operation is O(n) where n is the number
> of TVars accessed
On Mon, Dec 1, 2008 at 4:39 PM, Andrea Rossato
<[EMAIL PROTECTED]> wrote:
> Hello,
>
> I'm writing the bindings to a C library which uses, in some functions,
> global variables.
>
> To make it clearer, those functions need a global variable to be
> defined. A C program using my_function, one of the
This actually brings up something I was wondering about lately. I
recently stumbled across a language called clojure, which is a
lisp-like that runs on the JVM. The interesting thing is that
mutations go through a transactional mutable reference system, and the
other datastructures are all immuta
Here's what I have in one file:
-- | Parse the text of an event with the given parser @[EMAIL PROTECTED]
parse :: (Monad m) => P.CharParser () a -> String -> Derive.DeriveT m a
parse p text = do
(val, rest) <- case P.parse (p_rest p) "" text of
Left err -> Derive.throw $
"p
On Wed, Oct 1, 2008 at 3:39 PM, Bill <[EMAIL PROTECTED]> wrote:
> On Wed, 2008-10-01 at 16:46 -0400, John Van Enk wrote:
> . . .
>> I fully realize how un-clever this is. Some one please give me
>> something more worth of the original list. :)
>
> You shoot the gun but nothing happens (Haskell is
> As I understand, there are two ways to do that. Either Haskell code is
> called from C, or C code is called for Haskell. So my questions are:
> 1. Are they both possible?
Yep.
> 2. If yes, which is better performance-wise? (C function is
> performance-critical). If generated function is calle
On Wed, Sep 24, 2008 at 2:03 PM, Iain Barnett <[EMAIL PROTECTED]> wrote:
> Hi,
>
> I have a function, that produces a random number between two given numbers
>
> rand :: Int -> Int -> IO Int
> rand low high = getStdRandom (randomR (low,high))
>
>
> (Naively) I'd like to write something like
>
> tak
> In Haskell,
> "The sequence enumFromTo e1 e3 is the list [e1,e1+1,e1+2,...e3].
> The list is empty if e1 > e3."
I like it, since it means that things like [n .. n + length m - 1]
work as expected when m is []. Or say 'map (array!) [bsearch x ..
bsearch y - 1]'.
Tangent: Of course, I would pr
201 - 300 of 367 matches
Mail list logo
