Judah == Judah Jacobson judah.jacob...@gmail.com writes:
Judah On Wed, Aug 19, 2009 at 10:31 AM, Iain Barnettiainsp...@gmail.com
wrote:
Quick question: I've tested this in a couple of different
terminals (roxterm and xterm), so I'm fairly sure it's GHC
that's the problem.
Hello Colin,
Thursday, August 20, 2009, 10:13:28 AM, you wrote:
I don't understand where latin-1 comes into this. String is supposed
to be a list of Unicode characters.
but ghc 6.10 i/o used String as list of bytes
--
Best regards,
Bulat
Bulat == Bulat Ziganshin bulat.zigans...@gmail.com writes:
Bulat Hello Colin,
Bulat Thursday, August 20, 2009, 10:13:28 AM, you wrote:
I don't understand where latin-1 comes into this. String is supposed
to be a list of Unicode characters.
Bulat but ghc 6.10 i/o used String
Hi,
I had posted a note on line drawing algo with Haskell some time back. Now, I am
trying to write a PNM image.
import qualified Data.ByteString as B
width = 256
height = 256
bytesInImage = width * height * 3
blankImage = B.pack $ take bytesInImage (repeat 0)
type Color = (Int,Int,Int)
On Thu, Aug 20, 2009 at 4:28 PM, Colin Paul
Adamsco...@colina.demon.co.uk wrote:
But how do you get Latin-1 bytes from a Unicode string? This would
need a transcoding process.
The first 256 code-points of Unicode coincide with Latin-1. Therefore,
if you truncate Unicode characters down to 8
Stuart == Stuart Cook sco...@gmail.com writes:
Stuart On Thu, Aug 20, 2009 at 4:28 PM, Colin Paul
Stuart Adamsco...@colina.demon.co.uk wrote:
But how do you get Latin-1 bytes from a Unicode string? This
would need a transcoding process.
Stuart The first 256 code-points of
Hello Colin,
Thursday, August 20, 2009, 11:12:53 AM, you wrote:
Yes, but surely this will work both ways. The same bytes on input
should come back on output, shouldn't they?
only ascii subset that have fixed encoding. the rest may migrate in
some way
--
Best regards,
Bulat
On Thu, Aug 20, 2009 at 5:12 PM, Colin Paul
Adamsco...@colina.demon.co.uk wrote:
Yes, but surely this will work both ways. The same bytes on input
should come back on output, shouldn't they?
I would have thought so, but apparently this isn't actually what happens.
GHCi, version 6.8.2:
On Wed, Aug 19, 2009 at 1:20 PM, Peter Verswyvelenbugf...@gmail.com wrote:
Well I really wrote this code as an exercise, and it was a good one. Now I
(or someone) needs to explain why it works.
There's a bit of trickiness, but it's not that hard when you break it down.
Lets look at a
This is very very informative, thanks.
One thing I still struggle with (because I haven't practiced much I guess)
is writing down the desugaring/evaluation/expansion/reduction (how do you
call it?). I know how to do it more or less (tried it for a fix fac, since
fix feels like magic for an
Stuart Cook sco...@gmail.com writes:
GHCi, version 6.8.2: http://www.haskell.org/ghc/ :? for help
Loading package base ... linking ... done.
Prelude map Data.Char.ord 饁
[39233]== 0x9941
Prelude putStrLn 饁
A == 0x41
It seems that GHCi is clever enough to
Hi, all.
I've come into trouble defining function `gmap` which will work on these
data types:
data Row = Row
(E Name)
(E Salary)
(E Department)
type E a = Either (Maybe RowIndex) (Maybe a)
type RowIndex = Int
`RowIndex`, `Name`, `Salary`, `Department` have kind *
Peter Verswyvelen wrote:
Not at all, use it for whatever you want to :-)
I'm writing this code because I'm preparing to write a bunch of
tutorials on FRP, and I first wanted to start with simple console based
FRP, e.g. making a little text adventure game, where the input/choices
of the user
Sorry for a type and probably confusing you, it must be:
readRow l = gmap (\(Left (Just ri)) - Right $ l `atMay` ri = readMay)
instead of
l `atMay` c
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
Job Vranish wrote:
I've been in a situation a lot lately where I need to keep a collection of
values, and keep track of them by a persistent index.
data IndexedCollection a = IndexedCollection {
nextKey :: Int,
availableKeys :: [Int],
items :: IntMap a
} deriving
I don't fully understand.
interact gives you a stream of input characters that the user types, and
produces a stream of output characters that are displayed back (with
buffering set to NoBuffering). it should behave predictable no?
and since the input that the user gives depends on the output on
2009/8/20 Ketil Malde ke...@malde.org
Stuart Cook sco...@gmail.com writes:
GHCi, version 6.8.2: http://www.haskell.org/ghc/ :? for help
Loading package base ... linking ... done.
Prelude map Data.Char.ord 饁
[39233]== 0x9941
Prelude putStrLn 饁
A ==
Hi Max,
I've come into trouble defining function `gmap` which will work on these
data types:
data Row = Row
(E Name)
(E Salary)
(E Department)
type E a = Either (Maybe RowIndex) (Maybe a)
type RowIndex = Int
`RowIndex`, `Name`, `Salary`, `Department` have kind *
Goedemiddag café,
Consider the following function, using parsec-3.0.0:
la :: Parsec String () (Maybe Char)
la = lookAhead (optionMaybe anyChar)
*Lookahead parseTest (char 'a' | char 'b') a
'a'
*Lookahead parseTest (char 'a' | char 'b') b
'b'
*Lookahead parseTest (la * char 'a' | char 'b') a
On Aug 20, 2009, at 05:07 , Ketil Malde wrote:
% ghci -e 'map Data.Char.ord 饁'
interactive:1:21:
lexical error in string/character literal at character '\129'
but again:
% ghci -e 'map Data.Char.ord £'
[194,163]
So GHCi used interactively translates input from the
I'm pleased to announce the first public release of Ministg.
Ministg is an interpreter for a high-level, small-step, operational
semantics for the STG machine. The STG machine is the abstract machine
at the core of GHC. The operational semantics used in Ministg is taken
from the paper Making a
Hi all,
my haskell app is getting closer to shipping and what I need to do now is
to give product protection some thought. The product is for hospitals and
therefore a very limited set of clients. I do not expect anyone to try to
hack my application but I need a basic protection mechanism
On Wed, Aug 19, 2009 at 8:32 AM, Jules Beanju...@jellybean.co.uk wrote:
Do not blame haskell, blame emacs, if emacs is so stupid.
How can you blame emacs? Do you expect emacs to read programmer's minds?
John
___
Haskell-Cafe mailing list
John D. Ramsdell wrote:
On Wed, Aug 19, 2009 at 8:32 AM, Jules Beanju...@jellybean.co.uk wrote:
Do not blame haskell, blame emacs, if emacs is so stupid.
How can you blame emacs? Do you expect emacs to read programmer's minds?
No, I expect emacs to select a suitable first indentation
On Wed, Aug 19, 2009 at 11:38 PM, Chung-chieh
Shanccs...@post.harvard.edu wrote:
Thanks! Another small change that might shorten the code is to use
Data.Map for linear combinations:
I chose to use association lists because I did not want to explain the
adjust function one would use to
On Thu, Aug 20, 2009 at 9:08 AM, Jules Beanju...@jellybean.co.uk wrote:
I don't find layout a problem, with good editor support. I agree it's a
problem, with poor editor support. That's all I meant.
Let's put this issue in perspective. For those few Haskell
programmers that do find layout
On Thu, Aug 20, 2009 at 9:08 AM, Jules Beanju...@jellybean.co.uk wrote:
I don't find layout a problem, with good editor support. I agree it's a
problem, with poor editor support. That's all I meant.
Let's put this issue in perspective. For those few Haskell
programmers that do find layout
It seems that with Ryan's approach, DList is not needed, simple concat works
fine.
It also seems to run in constant space. Now I must do the exercise of
rewriting it to see why concat works, since = is infixl and ++ is infixr,
this seems odd :) But again, my mind might be thinking too strict (bad
Got this back from the bug tracker
6.12.1 will have Unicode support in the IO library which mostly fixes this
problem. The rest is fixed by #3398.
Iain
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
Hello,
I'm trying to find the API documentation for happstack 0.3 (online is
for 0.2).
So I did:
cabal install happstack --reinstall --enable-documentation
but I can't find it anywhere within ~/.cabal - where should I look?
--
Colin Adams
Preston Lancashire
John D. Ramsdell wrote:
On Thu, Aug 20, 2009 at 9:08 AM, Jules Beanju...@jellybean.co.uk wrote:
I don't find layout a problem, with good editor support. I agree it's a
problem, with poor editor support. That's all I meant.
Let's put this issue in perspective. For those few Haskell
Evan, Lennart
Thanks for the provocation. I've committed a patch that fixes all these
issues. Try now!
Simon
Thu Aug 20 13:34:43 BST 2009 simo...@microsoft.com
* Improvements to record puns, wildcards
* Make C { A.a } work with punning, expanding to C { A.a = a }
* Make it so
On Thu, Aug 20, 2009 at 2:52 AM, Jules Bean ju...@jellybean.co.uk wrote:
Peter Verswyvelen wrote:
Not at all, use it for whatever you want to :-)
I'm writing this code because I'm preparing to write a bunch of tutorials
on FRP, and I first wanted to start with simple console based FRP, e.g.
Colin Paul Adams co...@colina.demon.co.uk writes:
I'm trying to find the API documentation for happstack 0.3 (online is
for 0.2).
So I did:
cabal install happstack --reinstall --enable-documentation
but I can't find it anywhere within ~/.cabal - where should I look?
In most cases it is
and since the input that the user gives depends on the output on the screen
(it represents the user - machine dialog loop), we must make sure that
laziness does not go wild and strictness is needed to respect this
dependency. But as Ryan showed, seq is not really needed (but pattern
Max == Max Desyatov explicitc...@googlemail.com writes:
Max Colin Paul Adams co...@colina.demon.co.uk writes:
I'm trying to find the API documentation for happstack 0.3
(online is for 0.2).
So I did:
cabal install happstack --reinstall --enable-documentation
Sean Leather leat...@cs.uu.nl writes:
I'm not sure the problem you're running into is strictly a generic
programming (GP) one. Typically, GP takes code that is often written
and generalizes it, so that it doesn't have to be written for multiple
datatypes.
That seems to be GP problem, as your
Hello! I'm trying to derive Binary for StdGen with DrIFT:
module Main where
import System.Random
import Data.Binary
{-!for StdGen derive : Binary !-}
data Foo = Foo StdGen StdGen deriving (Show) {-! derive : Binary !-}
but I got error DrIFT: can't find module System/Random
What shall I do?
Yeah, that's weird. I played around with la and it seems to only cause
problems when the parser passed into lookAhead succeeds, which seem to go
directly against it's stated purpose.
lookAhead isn't consuming, (hence the unexpected b) but still prevents
| from doing it's thing.
Seems like a
Am Donnerstag 20 August 2009 13:44:15 schrieb Martijn van Steenbergen:
Goedemiddag café,
Consider the following function, using parsec-3.0.0:
la :: Parsec String () (Maybe Char)
la = lookAhead (optionMaybe anyChar)
*Lookahead parseTest (char 'a' | char 'b') a
'a'
*Lookahead parseTest
Grigory Sarnitskiy sargrig...@ya.ru writes:
Hello! I'm trying to derive Binary for StdGen with DrIFT:
[...]
but I got error DrIFT: can't find module System/Random
What shall I do?
I'd use
http://hackage.haskell.org/packages/archive/derive/2.0.1/doc/html/Data-Derive-Binary.html
instead.
Simple fix (terrible error message):
Move the ( up to the line with the module name. Previous bad code:
module Data.DualMap
-- * The @DualMap@ abstract type
( DualMap ()
-- * (?) internal? -- exposed for testing purposes, for now...
, dmFlip
-- * converting
That seems to be GP problem, as your solution doesn't scale well when I
wan't to add/remove/change fields in the `Row` record.
Ah yes, this is a good use case. I wasn't paying close enough attention
before, and I didn't see an immediate implementation of your function at the
time.
The
On Thu, Aug 20, 2009 at 7:37 AM, David Leimbachleim...@gmail.com wrote:
I'm pretty certain that forcing a pattern match via case is what disallows
the laziness to get out of hand. The case statement, when evaluated, must
choose a matched pattern branch, even if it's the only possibility, which
On Thu, Aug 20, 2009 at 9:56 AM, Ryan Ingramryani.s...@gmail.com wrote:
Compare these identical code fragments:
Er, strike identical. Oops! Comparing identical fragments would be boring.
-- ryan
___
Haskell-Cafe mailing list
Your setPixel function is almost ready to work in a State monad
If you modify your setPixel function slightly like so:
setPixel' :: Int - Int - Color - B.ByteString - ((), B.ByteString)
setPixel' x y (r,g,b) image = ((), B.concat [beforePixel, pixel,
afterPixel])
and then wrap it in the State
Using seq to control a program's semantics (as in, input-output
behaviour) is a horrible hack.
The seq operation there to control space and time aspects of your program.
(The specification of seq doesn't even say that the first argument is
evaluated before the second one.)
You should use data
Opps:
setPixel = State setPixel'
should be:
setPixel x y rgb = State $ setPixel' x y rgb
- Job
On Thu, Aug 20, 2009 at 1:05 PM, Job Vranish jvran...@gmail.com wrote:
Your setPixel function is almost ready to work in a State monad
If you modify your setPixel function slightly like so:
David Leimbach leim...@gmail.com writes:
I'm pretty certain that forcing a pattern match via case is what disallows
the laziness to get out of hand. The case statement, when evaluated, must
choose a matched pattern branch, even if it's the only possibility, which
ends up boiling down to seq
On Thu, Aug 20, 2009 at 1:02 PM, Ketil Maldeke...@malde.org wrote:
David Leimbach leim...@gmail.com writes:
I'm pretty certain that forcing a pattern match via case is what disallows
the laziness to get out of hand. The case statement, when evaluated, must
choose a matched pattern branch,
I'm trying to find the API documentation for happstack 0.3
(online is for 0.2).
[...]
Max In most cases it is installed in
Max ~/.cabal/share/doc/happstack*/html. Is there any files at
Max that directory?
There are now, but only a very few. And very little contents
Daniel Fischer wrote:
Am Donnerstag 20 August 2009 13:44:15 schrieb Martijn van Steenbergen:
Goedemiddag café,
Consider the following function, using parsec-3.0.0:
la :: Parsec String () (Maybe Char)
la = lookAhead (optionMaybe anyChar)
*Lookahead parseTest (char 'a' | char 'b') a
'a'
On Thu, Aug 20, 2009 at 8:58 AM, Colin Paul
Adamsco...@colina.demon.co.uk wrote:
Hello,
I'm trying to find the API documentation for happstack 0.3 (online is
for 0.2).
So I did:
cabal install happstack --reinstall --enable-documentation
but I can't find it anywhere within ~/.cabal -
try works in this case, but it won't if we are using a parser which can
consume and then fail (instead of char 'a'). In which case we may want it to
fail without exploring the second option.
Hmmm though you might be right. Having lookAhead return Consumed is only a
problem if the parser passed to
I totally agree that data dependencies are the best way to do that. And I'm
beginning to see why interact might not be suitable for demonstrating FRP.
On the other hand, when you say data dependencies, you mean that the value
of expression A depends on the value of expression B, but what if that
Apologies to Christian for the double post, didn't look at the To-field.
Am Thursday 20 August 2009 20:21:30 schrieben Sie:
Daniel Fischer wrote:
Am Donnerstag 20 August 2009 13:44:15 schrieb Martijn van Steenbergen:
Goedemiddag café,
Consider the following function, using parsec-3.0.0:
Peter,
I think you are right that there is no way in general to prevent a valid
graph rewrite to remove a vacuous dependency. That is why seq is there.
The funny business is visible right in the type signature of seq:
seq :: forall a t. a - t - t
If seq had nonstrict semantics, this would
On Thu, Aug 20, 2009 at 3:43 PM, Peter Verswyvelenbugf...@gmail.com wrote:
Also doesn't Haskell's IO system uses a hidden RealWorld type that has no
value but which is passed from between monadics binds in a strict way to
make the ordering work?
Haskell only describes how the IO monad
gue.schmidt:
Hi all,
my haskell app is getting closer to shipping and what I need to do now is
to give product protection some thought. The product is for hospitals and
therefore a very limited set of clients. I do not expect anyone to try to
hack my application but I need a basic
But how does GHC implement the RealWorld internally? I guess this can't be
done using standard Haskell stuff? It feels to me that if I would implement
it, I would need seq again, or a strict field, or some incrementing time
value that is a strict argument of each of the IO primitives. In any case,
On Thu, Aug 20, 2009 at 4:41 PM, Peter Verswyvelenbugf...@gmail.com wrote:
But how does GHC implement the RealWorld internally? I guess this can't be
done using standard Haskell stuff? It feels to me that if I would implement
it, I would need seq again, or a strict field, or some incrementing
On Thu, Aug 20, 2009 at 11:23 PM, David Menendez d...@zednenem.com wrote:
The important things to note are (1) getChar# depends on the token
returned by putChar#, thus guaranteeing that putChar# gets executed
first, and (2) putChar# and getChar# are impure and cannot normally be
defined in
On Thu, Aug 20, 2009 at 6:57 PM, Peter Verswyvelenbugf...@gmail.com wrote:
On Thu, Aug 20, 2009 at 11:23 PM, David Menendez d...@zednenem.com wrote:
The important things to note are (1) getChar# depends on the token
returned by putChar#, thus guaranteeing that putChar# gets executed
first,
Hello Peter,
Friday, August 21, 2009, 12:41:35 AM, you wrote:
But how does GHC implement the RealWorld internally? I guess
look the base library sources for RealWorld
--
Best regards,
Bulatmailto:bulat.zigans...@gmail.com
64 matches
Mail list logo
