Hi,
I'm looking for a function for Data.Map that will insert a new key and value
into the map if the key doesn't already exist in the map. When the key
already exists, I don't want the value updated in the map. Additionally, I
want to know whether the key/value was inserted or not so that I can
On 9 dec 2008, at 09:11, John Ky wrote:
Hi,
I'm looking for a function for Data.Map that will insert a new key
and value into the map if the key doesn't already exist in the map.
When the key already exists, I don't want the value updated in the
map. Additionally, I want to know
The biggest wart is that view is not a total function; the compiler
needs to be extra careful to only call it on types that are instances
of View. I wonder if there is a good way to solve this problem?
The usual way to solve this is to define a data type corresponding to
all the types in
Interesting. But from a practical point of view (I know, irrelevant!
*grin*), it's very tempting to piggyback the entirety of the typeclass
feature on a simple technique like this.
It also gives you the benefit that functions like this:
manyConstraints :: (Show a, Eq a, Data a) = a - Bool
end
On Mon, 2008-12-08 at 14:49 -0200, Mauricio wrote:
Hi,
I've just seen this from Distribution.ModuleName (ghc 6.10):
toFilePath $ ( simple A.B.C )
to which ghci answers: A.B.C.
Shouldn't it say A/B/C?
You're using it wrong. A 'simple' module name should have no '.' in it.
Instead use
Hello,
I don't know enough about the RealFrac class to answer this myself:
Can I be sure that
Numeric.readFloat :: ReadS Rational
never exhibits any rounding errors?
Thanks,
/ Emil
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On Thu, 2008-12-04 at 19:04 +0100, Niklas Broberg wrote:
Fellow Haskelleers,
it is my pleasure to announce the new release of the haskell-src-exts
package, version 0.4.4:
So when will we simply declare that haskell-src-exts is the new
haskell-src? :-)
That implementation is widely
Yes.
On Tue, Dec 9, 2008 at 1:54 PM, Emil Axelsson [EMAIL PROTECTED] wrote:
Hello,
I don't know enough about the RealFrac class to answer this myself:
Can I be sure that
Numeric.readFloat :: ReadS Rational
never exhibits any rounding errors?
Thanks,
/ Emil
On Sat, 2008-12-06 at 23:32 +0100, Laurent Giroud wrote:
Hi everyone,
I have been trying to install haskelldb in the last few days and
encountered a number of hurdles which raised a few questions and for
which I'd appreciate some insight and advice. Note that I am posting
here because
On Mon, Dec 8, 2008 at 23:10, Dan Piponi [EMAIL PROTECTED] wrote:
More generally, all of Tarski's high school algebra axioms carry
over to types. You can see the axioms here:
http://math.bu.edu/people/kayeats/papers/saga_paper4.ps That proves
type theory is child's play :-)
Ah, the power of a
Is there a user mailing list for the Timber language?
(http://www.timber-lang.org/)
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For later reference: I created a minimal test case to illustrate the
issue and moved to the (hopefully) more appropriate
glasgow-haskell-users list:
http://www.haskell.org/pipermail/glasgow-haskell-users/2008-December/016312.html
cheers,
andrea
On Sun, Dec 07, 2008 at 07:08:28PM +0100, Andrea
The duplicate definition error appears when I compile Main.hs and execute
it. But when I run it with runghc the behaviour is different. It works
well:
runghc Main.hs
3
Any idea? is this a bug of hs-plugins? it is just something expected??
2008/12/6 Alberto G. Corona [EMAIL PROTECTED]
I have
On 8 Dec 2008, at 23:15, Joachim Breitner wrote:
Am Montag, den 08.12.2008, 15:59 -0600 schrieb Nathan Bloomfield:
Slightly off topic, but the A^B notation for hom-sets also makes the
natural isomorphism we call currying expressable as A^(BxC) = (A^B)
^C.
So A^(B+C) = A^B × A^C ?
Oh,
Is there a change in strictness with the following transformation? It seems
like scanr should be a good consumer and a good producer, intuitively.
scanrFB :: (a - b - b) - b - [a] - (b - c - c) - c - c
scanrFB f x ls c n = snd (foldr (\ x (b, bs) - let b' = f x b in (b', b'
`c` bs)) (x, n) ls)
There is a subreddit for people to propose libraries:
http://www.reddit.com/r/haskell_proposals/
The idea being, that Web 2.0 will help us to allocate our
collective talents more efficiently when it comes to
extensions (and perhaps clue us in when our pet project is
something
Are SrcSpan's on the TODO list?
Seeing how this is the first I hear of them, I can't say that they
have been, but they could be. :-)
Could you give me a rundown on what usecases you'd need SrcSpans for,
and where HSE currently fails you in this regard?
Cheers,
/Niklas
Apart from this, HSE now also parses any unrecognized pragma in option
(e.g. LANGUAGE), declaration (e.g. RULES) or expression (e.g. SCC)
position, allowing user-customized pragmas. Unrecognized pragmas in
other positions will (unfortunately) give a parse error. If this ever
means a problem
Hi Duncan,
thanks a lot for your answers.
however, haskell-hdbc insists on depending on version 1.0.1.
That's because the haskelldb-hdbc depends on exactly HDBC ==1.0.1
http://hackage.haskell.org/cgi-bin/hackage-scripts/package/haskelldb-hdbc
I haven't been able so far to find what
(CC libraries)
So when will we simply declare that haskell-src-exts is the new
haskell-src? :-)
I talked about this with Ross Paterson at one point, and his main
objection (which I very much agree with) was that haskell-src-exts
doesn't let you *optionally* handle extensions, so in some cases
Hi,
I've just coded a small utility to prettyprint
my code, based on Language.Haskell.Parser and
friends. Much to my surprise it wasn't able to
parse itself, complaining about a non-ASC
character (í).
Why can ghc read the program, but not the standard
library parser? Does ghc use something
Hi,
how can I convert a file name with for example umlauts (ü, ä ... ) into
UTF8, or some other format that I can actually use it?
Günther
--
On a German Win XP
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redcom:
Hi,
how can I convert a file name with for example umlauts (ü, ä ... ) into
UTF8, or some other format that I can actually use it?
Günther
Using the utf8-string package to encode the file name string.
e.g.
x - readFile (encode ኃይሌ ገብረሥላሴ)
On 2008 Dec 9, at 20:21, Maurí cio wrote:
Why can ghc read the program, but not the standard
library parser? Does ghc use something else?
Is it possible to use whatever ghc uses to build
a prettyprinter?
Language.Haskell is known to be incomplete. The haskell-src-exts
package on
dons:
redcom:
Hi,
how can I convert a file name with for example umlauts (ü, ä ... ) into
UTF8, or some other format that I can actually use it?
Günther
Using the utf8-string package to encode the file name string.
e.g.
x - readFile (encode ኃይሌ ገብረሥላሴ)
Oh, perhaps you want to 'decode' the string that
dirOpenDialog returns.
redcom:
Hi Don,
must be doing something wrong.
The messed up string originates from calling Graphics.UI.WX.dirOpenDialog
and selecting a directory with Umlauts.
The encode function doesn't seem to help here as
I'd like to echo Jason's remarks earlier.
http://www.reddit.com/r/haskell_proposals/
We've tried for a couple of years now to efficiently track 'wanted
libraries' for the community, but never with much success.
In particular, two approaches have been tried:
* a wiki page
* the
On Tue, 9 Dec 2008 20:34:20 -0800, Don Stewart [EMAIL PROTECTED]
wrote:
I'd like to echo Jason's remarks earlier.
http://www.reddit.com/r/haskell_proposals/
We've tried for a couple of years now to efficiently track 'wanted
libraries' for the community, but never with much success.
In
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