kqueue is the low level interface, but requires that you handle all
file system events as they happen, and fast. There is a higher level
interface called fsevents (with accompanying daemon fseventsd) which
allows you a more calm way to read the file system events.
.
This is my understanding, not having used either directly (I've only
used inotify on linux).
-Ross
On Dec 4, 2009, at 11:39 AM, Svein Ove Aas wrote:
On Fri, Dec 4, 2009 at 5:31 PM, Ross Mellgren rmm-hask...@z.odi.ac
wrote:
kqueue is the low level interface, but requires that you handle
all file
On Dec 4, 2009, at 5:30 PM, Bryan O'Sullivan wrote:
On Fri, Dec 4, 2009 at 8:39 AM, Svein Ove Aas svein@aas.no
wrote:
That said.. you say you have to handle the events fast. What happens
if you don't?
If you don't handle events quickly, they're typically thrown away by
the kernel
It looks like it is specified and the intended behavior:
From the report, section 5.2:
An algebraic datatype T declared by a data or newtype declaration may
be named in one of three ways:
The form T names the type but not the constructors or field names. The
ability to export a type without
Control.Concurrent.STM
On Nov 24, 2009, at 6:11 PM, zaxis wrote:
I cannot hoogle it. It appears in Pugs:
run' (-d:rest) = do
info - fmap Just (io $ newTVarIO Map.empty)
let ?debugInfo = info
run' rest
Sincerely!
-
fac n = foldr (*) 1 [1..n]
--
View this
I've written a simple incomplete binding to graphviz-as-a-library to
do in-process graphviz layouts, though I would say it's hardly
complete so I haven't released it. If it's useful to someone and they
want to put in some additional elbow grease to make the particular
features they want
Also /usr/bin/ghci, /usr/bin/runghc, /usr/bin/runhaskell to patch up all the
holes. There may be others, also.
Here is a reference to the original thread where someone found out SL broke GHC
and then worked through temporarily resolving it:
They're two different 'env's, which can be observed by desugaring the
do-notation:
do env - liftIO (readIORef envRef)
env - return (filter (\(_id, _) - _id /= id) env)
...
Desugaring do-notation gets us:
liftIO (readIORef envRev) = \ env -
return (filter (\(_id, _) - _id /= id) env) = \ env
According to the paste you gave for the JHC test run:
Here is what happens when I try to run it:
phi...@desktop:~/jhctut$ ./jtree
Give me a tree:
T AND (L 1, L 2)
jtree_code.c:2670: case fell off
Aborted
You gave it parens not square brackets.
-Ross
On Nov 11, 2009, at 11:45 AM, Philippos
You did not specify what type of number it is -- in Haskell numeric
constants like 1 are actually typed as forall a. Num a -- that is,
can be any type of Num.
Try: plus (2::Int) 3
-Ross
On Nov 9, 2009, at 1:44 PM, Paul Tokarev wrote:
Hi.
I am using Hugs 98
I have that piece of code:
a
typeclass, instead just write the function directly --
plus :: Int - Int - Int
plus = (+)
-Ross
On Nov 9, 2009, at 5:09 PM, Paul Tokarev wrote:
Thanks, that works. But how sould I change my class definition, so
that it
works without (2::Int), but just with 2?
Ross Mellgren wrote:
You did
http://www.haskell.org/onlinereport/basic.html
6.3 Standard Haskell Classes
-Ross
On Oct 26, 2009, at 3:13 PM, michael rice wrote:
Got it. No doubt some of this figures into why I was beaten bloody
by ghci last night. Is there a number tree somewhere that shows
the heirarchy?
Michael
Andrew has mentioned the debugger several times, NOT the interactive
REPL. That is, using :-commands to inspect values.
-Ross
On Oct 16, 2009, at 2:46 PM, Daniel Peebles wrote:
My GHCi can't do that :o
I just wrote data A = B | C and loaded the file into GHCi. Typing B
gives me:
No problem, just trying to make sure the conversation stays on track :-)
-Ross
On Oct 16, 2009, at 3:26 PM, Daniel Peebles wrote:
Whoops, sorry about that then!
On Fri, Oct 16, 2009 at 2:59 PM, Ross Mellgren rmm-
hask...@z.odi.ac wrote:
Andrew has mentioned the debugger several times
I didn't try to compile this:
import Control.Arrow (first)
import System.Random (Random(..))
instance Random Dir where
randomR (lo, hi) gen = first fromEnum (randomR (toEnum lo)
(toEnum hi) gen)
random gen = randomR (minBound, maxBound)
But something along those lines should help
In what Monad?
-Ross
On Oct 9, 2009, at 5:43 PM, staafmeister wrote:
In my program
do
x - do
blah - someFunc
return blah
return $ Constructor x
behaves differently from
do
blah - someFunc
return $ Constructor blah
where the dots are identical. I would think that these programs
You're running into this problem because you're in a do-block. In a do-
block, all the continuing lines of a single statement in the do-block
must be indented w/r/t to the first line. The cylinder example doesn't
have this issue because it's not in a do-block.
The layout rule (I'm
I don't know of any offhand that specifically call it out -- it's a
natural consequence of the layout rule which is described in the
Haskell Report. However, there is at least one ticket in Haskell' to
fix it for if/then/else: http://hackage.haskell.org/trac/haskell-prime/ticket/23
-Ross
I don't think a list comprehension is the easiest way to do it, how
about
upperCase :: String - String
upperCase [] = []
upperCase (x:xs) = toUpper x : map toLower xs
-Ross
On Oct 7, 2009, at 4:48 PM, Steven1990 wrote:
Hi, I'm currently learning Haskell, and I've been trying to work out a
car = head
letting the compiler infer the type, or
car :: [a] - a
car = head
for the explicit version.
-Ross
On Oct 6, 2009, at 10:01 PM, michael rice wrote:
How do I create an alias for a function, like giving CAR the same
functionality as HEAD. I know I can do it by creating a
What about the built-in Float type?
Prelude Foreign.Storable sizeOf (undefined :: Float)
4
Prelude Foreign.Storable sizeOf (undefined :: Double)
8
Or maybe you mean something that can be used with FFI calls to C, in
which case Foreign.C.Types (CFloat).
Both instance the Floating, RealFloat,
.
But these days I guess 32-bit is the minimum one would want to use?
Most of the time I just use double anyway :)
On Sun, Sep 27, 2009 at 9:47 PM, Ross Mellgren rmm-
hask...@z.odi.ac wrote:
What about the built-in Float type?
Prelude Foreign.Storable sizeOf (undefined :: Float)
4
Prelude
Well, keep in mind forkIO *might* be a different OS thread (unless
it's bound, IIRC), depending on the number of workers (with -Nx) and
so on.
-Ross
On Sep 23, 2009, at 2:24 PM, Günther Schmidt wrote:
Am 23.09.2009, 19:29 Uhr, schrieb Duncan Coutts duncan.cou...@worc.ox.ac.uk
:
On Tue,
Ah yeah, that too. Control.Parallel.Strategies.rnf to the rescue?
-Ross
On Sep 15, 2009, at 4:17 PM, Cristiano Paris wrote:
On Tue, Sep 15, 2009 at 10:12 PM, Ross Mellgren rmm-
hask...@z.odi.ac wrote:
Wouldn't seq b only force (at minimum) the first character of the
file?
I think it force
Ack, IGNORE ME! Way too strict.
-Ross
On Sep 15, 2009, at 4:20 PM, Ross Mellgren wrote:
Ah yeah, that too. Control.Parallel.Strategies.rnf to the rescue?
-Ross
On Sep 15, 2009, at 4:17 PM, Cristiano Paris wrote:
On Tue, Sep 15, 2009 at 10:12 PM, Ross Mellgren rmm-
hask...@z.odi.ac wrote
Wouldn't seq b only force (at minimum) the first character of the file?
-Ross
On Sep 15, 2009, at 4:08 PM, Cristiano Paris wrote:
On Tue, Sep 15, 2009 at 9:29 PM, Daniel Fischer
daniel.is.fisc...@web.de wrote:
Am Dienstag 15 September 2009 21:13:02 schrieb Daniel Fischer:
Still, the body
It sounds like it's looking for the binary package -- you should
install it using cabal, e.g.
private (per-user) install:
cabal update
cabal install binary
global (system-wide) install:
sudo cabal update
sudo cabal install --global binary
-Ross
On Sep 8, 2009, at 7:57 PM, John Velman wrote:
(but not Cabal), and have been
Xcoding with
Objective C for a year or so now, but never tried this before. I am
interested in HOC, but I've obviously got a lot to learn.
Thanks again,
John Velman
On Tue, Sep 08, 2009 at 08:35:54PM -0400, Ross Mellgren wrote:
It sounds like it's looking for the binary
My 6.10.1 install still works alright after upgrade to 10.6/Snow
Leopard. What version did you have?
-Ross
On Aug 28, 2009, at 7:15 PM, David Leimbach wrote:
Just thought I'd point out that my old GHC install is now broken by
the update to Snow Leopard.
Dave
correct assembly code (it looks like).
Dave
On Fri, Aug 28, 2009 at 4:55 PM, Ross Mellgren rmm-
hask...@z.odi.ac wrote:
My 6.10.1 install still works alright after upgrade to 10.6/Snow
Leopard. What version did you have?
-Ross
On Aug 28, 2009, at 7:15 PM, David Leimbach wrote:
Just
I don't think getNameInfo should work for for AF_UNIX -- the name
given to SockAddrUnix is a file path, there is no name resolution.
From the man page for getnameinfo(3) on OS X:
NAME
getnameinfo -- socket address structure to hostname and service name
...
DESCRIPTION
...
The
I've seen this expressed with GADTs (which I guess many things can),
though I'm not sure if it's the best way, and I'm no type system
wizard. If I recall correctly, this use is normally called phantom
types.
{-# LANGUAGE EmptyDataDecls, GADTs #-}
data Even
data Odd
data Foo a where
Cons 'a' (Cons 'b' (Cons 'c' Nil))
equivalent to
'a' : ('b' : ('c' : []))
using Haskell's normal list type.
-Ross
On Jul 25, 2009, at 2:55 AM, Futari wrote:
Hi, I was trying to use the solution given, but I don't know how to
use it...
How do I create something that is of type List?
It's not where -- let also works
let { foo Prelude let { foo x = x } in (foo 1, foo True)
(1,True)
Can you send the code you're trying that doesn't work?
-Ross
On Jul 16, 2009, at 3:40 PM, Andrew Coppin wrote:
Robert Greayer wrote:
f0 _ = (foo True, foo 'x') where foo = id
is well-typed.
Is everything an acceptable answer?
-Ross
On Jul 16, 2009, at 6:38 PM, Derek Elkins wrote:
On Thu, Jul 16, 2009 at 2:52 PM, Andrew
Coppinandrewcop...@btinternet.com wrote:
Ross Mellgren wrote:
It's not where -- let also works
Prelude let { foo x = x } in (foo 1, foo True)
(1,True
I agree -- I think the most major learning curve problem (for me) was
not learning haskell directly, it was un-learning all those patterns
and workarounds and so on from imperative/OOP languages.
Of course, the only problem with learning haskell first is that one
will probably be mildly
Yes, using lazy semantics.
http://www.haskell.org/haskellwiki/Tying_the_Knot
-Ross
On Jul 14, 2009, at 6:27 PM, John Ky wrote:
Hello,
Is it possible to create a circular pure data structure in Haskell?
For example:
a :: Data
let b = getNext a
let c = getNext b
c == a -- Gives True
Wordy (and yet technically accurate) names aside, isn't this basically
the same thing, except that you must pass the dictionary around by hand?
What is the advantage of doing the dictionary passing manually, other
than being able to avoid the scoping issue (that requires case) and
the
You have a couple problems here.
The first is that GHC has no idea what particular type 'w' widgetList
has, because the empty list is polymorphic.
The second is that it looks like you probably want a heterogeneous
list of widgets -- that is, possibly different types of widget as long
as
I presume that many of the developers do not have windows machines
(presumably because windows sucks). Maybe you could help them by
trying to track down where the error in the code is, and even better
yet submitting a patch?
This is all free by the virtue of people giving what time they
. The converse
is true.
Why would you want it to generate a polymorphic Foobar when it
definitely is NoZoo?
-Ross
(p.s. the example names in this thread are a bit ridiculous ;-) )
On Jun 23, 2009, at 4:01 PM, Andrew Coppin wrote:
Ross Mellgren wrote:
This works for me:
{-# LANGUAGE EmptyDataDecls
This works for me:
{-# LANGUAGE EmptyDataDecls, GADTs #-}
module Main where
data NoZoo
data Zoo
newtype X = X Int deriving (Show)
newtype Y = Y Char deriving (Show)
data Foobar a where
Foo :: X - Y - Foobar NoZoo
Bar :: X - Y - Foobar NoZoo
Zoo :: Foobar NoZoo - Foobar Zoo
foobar
Really, without code or more than it just disappears, it's just
conjecture what's happening. Can you post the code, or even better yet
a minimized case that reproduces it?
-Ross
On Jun 20, 2009, at 1:34 PM, Andrew Coppin wrote:
Alexander Dunlap wrote:
On Sat, Jun 20, 2009 at 8:29 AM,
It looks offhand like you're not being strict enough when you put
things back in the IORef, and so it's building up thunks of (+1)...
With two slight mods:
go 0 = return ()
go n = do modifyIORef ior (+1)
go (n-1)
--
go 0 = return ()
go n = do modifyIORef ior (\ x -
, 2009 at 9:55 PM, Ross Mellgren rmm-
hask...@z.odi.ac wrote:
It looks offhand like you're not being strict enough when you put
things back in the IORef, and so it's building up thunks of (+1)...
With two slight mods:
go 0 = return ()
go n = do modifyIORef ior (+1)
go (n-1
Here's a way using list comprehensions:
Prelude Data.List take 1000 $ concat.concat $ [ [ replicate n c | c
- ['a'..'z'] ] | n - [1..] ]
abcdefghijklmnopqrstuvwxyzaabbccddeeffgghhiijjkkllmmnnooppqqrrssttuuvvw
Oh sorry about that, misread the problem.
-Ross
On Jun 16, 2009, at 9:16 PM, Günther Schmidt wrote:
Dear Ross,
thanks for your post, you got it almost right, I needed something
like aa, ab, ac ...
It seems that Thomas has figured it out.
Günther
If your module statements say Swish in them, e.g.
module Swish.HaskellUtils.TestHelpers where
then you should probably have no hs-source-dirs (or hs-source-dirs: .)
and then use Swish.HaskellUtils.TestHelpers.
But leave Main-Is: as you have it.
-Ross
On Jun 5, 2009, at 4:49 PM,
You've applied two solutions to get the value out -- pattern matching
(Just reinfo) and fromJust. You should use one or the other, but not
both:
-- pattern matching
remLookupFwd :: (ReVars m t) = SimplRe t - ReM m t (ReInfo t)
remLookupFwd re
= do fwd - gets resFwdMap
let { Just
P Float is the constructor to create a value of this type, similar to
data declarations.
That is, 0.5 :: Float, P 0.5 :: Probability
The {} notation after D creates a record accessor, also similar to
data declarations. It's equivalent to making an unD that unwraps the
value yourself:
True, so perhaps better written as:
import Data.Maybe (fromMaybe)
gets (fromMaybe (error could not find re in resFwdMap) . M.lookup
re . resFwdMap)
with more detail in error message as appropriate.
-Ross
On Jun 3, 2009, at 5:57 PM, Henning Thielemann wrote:
Ross Mellgren schrieb
mplus is a method of class MonadPlus, so you need to write it in a
separate instance from the one for Monad, e.g.
instance MonadPlus Failable where
mplus = ...
-Ross
On Jun 1, 2009, at 9:28 PM, michael rice wrote:
Still stumped. Maybe and [] are in the same MonadPlus monad, but how
do
it mplus)?
Michael
--- On Mon, 6/1/09, Ross Mellgren rmm-hask...@z.odi.ac wrote:
From: Ross Mellgren rmm-hask...@z.odi.ac
Subject: Re: [Haskell-cafe] Missing a Deriving?
To: michael rice nowg...@yahoo.com
Cc: haskell-cafe Cafe haskell-cafe@haskell.org
Date: Monday, June 1, 2009, 9:33 PM
mplus
:
From: michael rice nowg...@yahoo.com
Subject: Re: [Haskell-cafe] Random number example
To: Ross Mellgren rmm-hask...@z.odi.ac
Cc: haskell-cafe@haskell.org
Date: Thursday, April 23, 2009, 5:49 PM
Hi Ross,
Thanks for going the extra mile. A lot of what you did I haven't
seen before, so it's going
Hahah yeah of course, I left it implicit that you'd only do this if
you were changing the types (e.g. parameterized monads or what have you)
-Ross
On Apr 23, 2009, at 5:15 AM, Heinrich Apfelmus wrote:
Ross Mellgren wrote:
True enough -- if you really want to redefine the monadic operator
So there are a couple problems. First is you are trying to rebind
prelude functions, when instead you should be creating an instance of
Monad. This requires a bit of shuffling because without language
extensions you can't instance Monad Random for your type of Random, as
it is a type
I think
import Prelude hiding (())
does that.
-Ross
On Apr 22, 2009, at 11:44 AM, michael rice wrote:
I've been working through this example from:
http://en.wikibooks.org/wiki/Haskell/Understanding_monads
I understand what they're doing all the way up to the definition of
(), which
], whereas you might have hoped for [3,4] [5] = error Call
me!
Dan
Ross Mellgren wrote:
I think
import Prelude hiding (())
does that.
-Ross
On Apr 22, 2009, at 11:44 AM, michael rice wrote:
I've been working through this example from:
http://en.wikibooks.org/wiki/Haskell/Understanding_monads
I
If you want to just get the value out, meaning you'll get a program
error if it happens to be Nothing, then you can use
Data.Maybe.fromJust. But usually, you'd want to preserve the Nothing.
Applicative or Monad is pretty good for this:
import Control.Applicative
(3+) $ safeDivision 10 5
There's nothing connecting the Enum/Bounded used in fromEnum and min/
maxBound to the toEnum, as there's an Int in the middle. Annotated
very explicitly, the type inferrer probably sees something like:
randomEnum :: (Enum a, Bounded a, RandomGen g) = Rand g a
randomEnum = do
let minb =
Unfortunately the .DMG based frameworks do not have the cairo svg
framework (or the opengl framework), and it's non-trivial to get it
added on. If you need it, best bet right now is probably to go for a
macports install.
-Ross
On Mar 31, 2009, at 8:01 AM, Sebastian Fischer wrote:
On
I think my brain just exploded.
On Mar 30, 2009, at 1:29 PM, Edward Kmett wrote:
First, BASIC, now C. What's next, Haskell? =)
-Edward Kmett
On Sun, Mar 29, 2009 at 5:16 AM, Lennart Augustsson lenn...@augustsson.net
wrote:
I've uploaded my CMonad package to Hackage. It allows you to
I think you probably mean ==, the comparison operator (function), not
= (assignment in let-forms or where-forms)
-Ross
On Mar 29, 2009, at 1:40 PM, michael rice wrote:
Hi,
Thanks again for the help last night.
The second function cf2 is an attempt to reverse the process of the
first
I thought that HAppS has gone, replaced by happstack?
http://happstack.com/
-Ross
On Mar 24, 2009, at 11:32 AM, Vimal wrote:
Hi,
http://happs.org/ has some Javascript visible as plain text. It looks
like some tags are missing in the page...
I hope that's the right website, because it
Doesn't matter how many times you seq the results, the thunk has been
forced.
-Ross
On Mar 24, 2009, at 4:45 PM, FFT wrote:
I demand a recount! The one that launches the missile should have won!
2009/3/24 Eelco Lempsink ee...@lempsink.nl:
The results of the Haskell logo competition are
import Diebold.Unsafe (unsafeChangeVotes)
...
?
-Ross
On Mar 24, 2009, at 4:47 PM, John Van Enk wrote:
Unless there's a rogue unsafeChangeVotes call in there somewhere.
On Tue, Mar 24, 2009 at 4:46 PM, Ross Mellgren rmm-
hask...@z.odi.ac wrote:
Doesn't matter how many times you seq
As (yet another?) Haskell newbie, with a day job using Java (where
keep it simple, stupid is not a principle, it's a language enforced
requirement), I would much prefer the function is implemented in the
most concise and idiomatic style that the writer is capable of. That
is, either the
Paul Adams wrote:
Ross == Ross Mellgren rmm-hask...@z.odi.ac writes:
Ross While there is not a .dmg for Gtk2Hs, you can use a .dmg
Ross installed GHC with a .dmg installed Gtk, and then build
Ross gtk2hs straight on top of that, without having to deal with
Ross the dual-GHC macports
Minor correction -- pango in general is installed with the .DMG of
Gtk... it's pangoft2 (the freetype2 bindings) that librsvg requires
and aren't provided.
-Ross
On Mar 21, 2009, at 12:35 PM, Ross Mellgren wrote:
I tried making this work, but librsvg requires pango, and pango is a
huge
be identifiers.
I think I've seen this before - some well-known Mac OSX problem? (I'm
a linux man myself - so I'm not used to the mac)
2009/3/21 Ross Mellgren rmm-hask...@z.odi.ac:
I tried making this work, but librsvg requires pango, and pango is
a huge
pain in the ass -- I managed to get
2009/3/21 Ross Mellgren rmm-hask...@z.odi.ac:
I think there must be a version inconsistency with your GLib
framework --
either not the most recent copy of the GTK+ DMG, or your path is
flipped
around and you're using a ports version.
Run glib-mkenums --version to see what version you have... I
doesn't find it.
2009/3/21 Ross Mellgren rmm-hask...@z.odi.ac:
(back to the list)
Answers inline:
On Mar 21, 2009, at 2:42 PM, Colin Adams wrote:
Yes, that was the problem, and swapping the PATH order does the
trick.
Thanks.
no prob.
I must still have the macports stuff installed. Can
wrote:
And the reason is that librsvg fails to find cairo, pangocairo and
cairo-png.
Where is it supposed to find them?
2009/3/21 Colin Adams colinpaulad...@googlemail.com:
It didn't.
2009/3/21 Ross Mellgren rmm-hask...@z.odi.ac:
Did the configure for gtk2hs claim that it was going to build
While there is not a .dmg for Gtk2Hs, you can use a .dmg installed GHC
with a .dmg installed Gtk, and then build gtk2hs straight on top of
that, without having to deal with the dual-GHC macports mess..
http://www.haskell.org/haskellwiki/Gtk2hs#Using_the_GTK.2B_OS_X_Framework
-Ross
On Mar
ForeignFunctionInterface#-} instead
package.conf.inplace: openBinaryFile: does not exist (No such file
or directory)
make[1]: *** [glib/System/Glib.o] Error 1
make: *** [all] Error 2
On Fri, Mar 20, 2009 at 2:27 PM, Ross Mellgren rmm-
hask...@z.odi.ac wrote:
While there is not a .dmg for Gtk2Hs, you can use a .dmg
I use this configuration exclusively... it wasn't actually that hard
to set up once I found out that the .pc files are shipped in a strange
directory buried in the frameworks.
I posted how I got it working back in December:
Are you by chance using OSX? The file you attached was not a plain
text file -- it was an RTF file.
If you made this file on OSX and forgot to invoke the Format Make
Plain Text command, it'll be an RTF file which I'm sure gitit will
have no clue about.
-Ross
On Feb 26, 2009, at 10:21
I use Haskell under OSX only. I find it very well supported.
-Ross
On Feb 25, 2009, at 2:37 PM, Cristiano Paris wrote:
Hi,
I'm planning to purchase a MacBookPro so I'm wondering how well
Haskell is supported under this platform.
Thanks,
Cristiano
Now perhaps I'll be stepping into some lines of fire as it seems like
this thread is full of them. If I get in anyone's way please kindly
hold your shot ;-)
That said, video codecs are the kinds of things that usually benefit
greatly from vectorization and parallelization right? These are
This is a known issue:
http://hackage.haskell.org/trac/ghc/ticket/1993
Try:
cabal install --ghc-options=-fregs-graph Crypto
and then try installing happs-tutorial again.
-Ross
On Feb 11, 2009, at 4:31 PM, Daryoush Mehrtash wrote:
When i try to cabal install happs-tutorial I get the
I think you can use Data.Word and Data.Int types for this, that is.
Data.Word.Word16 == uint16_t, Data.Word.Word32 == uint32_t, etc.
Data.Int.Int16 = int16_t, Data.Int.Int32 = int32_t, etc.
There are Foreign.Storable.Storable instances for those.
-Ross
On Feb 10, 2009, at 6:32 AM, Maurí cio
The FFI spec says (at http://www.cse.unsw.edu.au/~chak/haskell/ffi/ffi/ffise3.html#x6-120003.2)
:
The argument types at[i] produced by fatype must be marshallable
foreign types; that is, each ati is either (1) a basic foreign type or
(2) a type synonym or renamed datatype of a marshallable
fatype is the function argument type. atype[i] are type arguments.
qtycon is a qualified (e.g. possibly with module prefix) type
constructor, e.g. Just
So, for example if you have:
foreign import ccall string.h strlen cstrlen :: Ptr CChar - IO CSize
fatype - ftype :: ftype
fatype ::
Prelude let i2fDiv a b = fromIntegral a / fromIntegral b
Prelude :t i2fDiv
i2fDiv :: (Integral a, Fractional b, Integral a1) =
a - a1 - b
Prelude 10 `i2fDiv` 3
3.3335
That what you're looking for?
-Ross
On Feb 4, 2009, at 4:22 PM, Manlio Perillo wrote:
Manlio
The type of hello is String, which is [Char], which is really []
Char (that is, the list type of kind * - *, applied to Char).
1, 'a', and True are all simple types (I'm sure there's a more
particular term, maybe monomorphic?) with no type arguments.
[] has a type argument, Char.
to the second element of the list
(if any) (here, Integer - Integer).
It worked well until I tried it on a function like :: Char - Int -
[Char] where
the last recursive call gives [Char] instead of [].
Is it possible to write such a function ?
Thank you,
Thu
2009/2/2 Ross Mellgren rmm-hask
Duncan, I think you must have some magics -- on my machine the
original code also takes forever.
Running with +RTS -S indicates it's allocating several gig of memory
or more.
Applying some bang patterns gives me ~8s for 10^8 and somewhat more
than a minute for 10^9:
{-# LANGUAGE
Yeah, you know after sending the email (never a better time) I noticed
that the C version wasn't spitting out the right answer. I'm not
really sure why, I just replaced bigint with int64_t from stdint.h.
-Ross
On Jan 28, 2009, at 8:32 PM, Benedikt Huber wrote:
Ross Mellgren schrieb
Apparently 64-bit GHC is sufficiently advanced to be indistinguishable
from magic. Now, if only there was a 64-bit binary for Mac OS X :-/
-Ross
On Jan 28, 2009, at 9:06 PM, Jake McArthur wrote:
Ross Mellgren wrote:
Duncan, I think you must have some magics -- on my machine the
original
Hi all,
I'm writing a small module that exposes a template haskell splice that
takes a (very simplified) C struct definition and builds:
- A data type definition,
- an instance for Data.Binary.Binary,
- and optionally a pretty print function for it
However, it seems to do this I have to
makeFilter :: (b - b - Bool) - (a - b) - b - a - Bool
makeFilter (==) proj expected = (expected ==) . proj
makeEqFilter :: Eq b = (a - b) - b - a - Bool
makeEqFilter = makeFilter (==)
Then you have a foo:
data Foo = Foo { fooA :: String, fooB :: Int }
foos = [Foo a 1, Foo b 2]
filter
, however, so I'm not sure it's entirely necessary.
Thanks again.
On Fri, Jan 23, 2009 at 05:39:07PM -0500, Ross Mellgren wrote:
makeFilter :: (b - b - Bool) - (a - b) - b - a - Bool
makeFilter (==) proj expected = (expected ==) . proj
makeEqFilter :: Eq b = (a - b) - b - a - Bool
makeEqFilter
I personally spurned MacPorts for this reason (and others). I've had
good success using the GTK+ Aqua framework from http://www.gtk-
osx.org/ and manually compiling pkg-config and gtk2hs from the darcs
repository. The only trick was to set PKG_CONFIG_PATH appropriately
before running
For what it's worth, many (most/all?) programmers I know in person
don't have the slightest clue about Category Theory and they may have
known about abstract algebra once upon a time but certainly don't
remember any of it now. They usually understand the concepts perfectly
well enough but
to convey the meaning of it and gives an
example.
-- Lennart
On Thu, Jan 15, 2009 at 4:46 PM, Ross Mellgren rmm-
hask...@z.odi.ac wrote:
For what it's worth, many (most/all?) programmers I know in person
don't
have the slightest clue about Category Theory and they may have
known about
abstract
On Jan 15, 2009, at 1:21 PM, David Menendez wrote:
On Thu, Jan 15, 2009 at 11:46 AM, Ross Mellgren rmm-
hask...@z.odi.ac wrote:
Second is that there appears to be no way to document an
_instance_. It
would be really handy if there were even a single line under
Instances
Monoid
Did you mean:
B.intercalate (B.intercalate ByteString [ByteString]) [ByteString]
($) applies all the way to the right, so you were giving the inner
intercalate two lists of ByteString.
-Ross
On Jan 5, 2009, at 1:17 PM, Galchin, Vasili wrote:
Hi Max,
That is what should happen
, Jan 5, 2009 at 12:18 PM, Ross Mellgren rmm-
hask...@z.odi.ac wrote:
Did you mean:
B.intercalate (B.intercalate ByteString [ByteString]) [ByteString]
($) applies all the way to the right, so you were giving the inner
intercalate two lists of ByteString.
-Ross
On Jan 5, 2009, at 1:17 PM
On Dec 29, 2008, at 3:43 PM, Andre Nathan wrote:
On Mon, 2008-12-29 at 14:19 -0500, Ross Mellgren wrote:
The problem is that you're trying to take a STMatrix from some other
ST computation and freeze it in a new ST computation. The isolation
between separate computations is done via the rank-2
It does require a mathematical mind, but does not require that you
understand the mathematical language. If mathematics are the basis of
computation, and programming is an implementation of computation, then
in many ways programming languages are a (less powerful) equivalent
language to
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