Hello,
I'm new in haskell. I want to use xml library
(http://hackage.haskell.org/package/xml) in my project.
I downloaded it.then try to build and install:
runhaskell Setup.hs configure
runhaskell Setup.hs build
runhaskell Setup.hs install
All ok. There are no errors. When i try import mod
At Sun, 26 Jun 2011 01:41:01 +0100,
Paterson, Ross wrote:
>
> > I thought "no type signature" meant no type signature inside b1.
>
> No, it means no type signature for the variable.
>
> > Otherwise, you are saying nothing could depend on a binding with a
> > type signature. By that logic, there
I've tended to use the attached module.
It is basic, but has covered my needs.
It probably has many issues (bugs, inefficiencies, naming conventions,
etc) but has been sufficient so far.
Developed by myself a few years ago, under no particular licence - happy
for reuse or for someone to take it
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
I recently set out to write a library that required a decent time
library. Having only had a flirt with Data.Time previously, I assumed
it would be robust like many other haskell libraries. I don't know
about consensus, but I have been massively let d
> I thought "no type signature" meant no type signature inside b1.
No, it means no type signature for the variable.
> Otherwise, you are saying nothing could depend on a binding with a
> type signature. By that logic, there can be no mutual dependence,
> and so every declaration with a type sign
At Sun, 26 Jun 2011 00:17:12 +0100,
Paterson, Ross wrote:
>
> > > > g1 x y z = if x>y then show x ++ show z else g2 y x
> > > >
> > > > g2 :: (Show a, Ord a) => a -> a -> String
> > > > g2 | False = \p q -> g1 q p ()
> > > >| otherwise = \p q -> g1 q p 'a'
> > > >
On Sat, Jun 25, 2011 at 10:18 PM, wren ng thornton wrote:
> On 6/25/11 6:51 AM, John Lato wrote:
> > Honestly I'm quite dis-satisfied with the current state of code which
> > depends on iteratee/enumerator. It's nearly all written in a very
> low-level
> > style, i.e. directly writing 'liftI step
> > > g1 x y z = if x>y then show x ++ show z else g2 y x
> > >
> > > g2 :: (Show a, Ord a) => a -> a -> String
> > > g2 | False = \p q -> g1 q p ()
> > >| otherwise = \p q -> g1 q p 'a'
> > >where x = True
> >
> > It appears to me that GHC is justified. Accordin
At Sat, 25 Jun 2011 14:20:52 -0400,
Scott Turner wrote:
>
> > g1 x y z = if x>y then show x ++ show z else g2 y x
> >
> > g2 :: (Show a, Ord a) => a -> a -> String
> > g2 | False = \p q -> g1 q p ()
> >| otherwise = \p q -> g1 q p 'a'
> >where x = True
>
> It a
On 6/25/11 2:15 PM, Erik Hesselink wrote:
> On Sat, Jun 25, 2011 at 19:07, Evan Laforge wrote:
>> On Sat, Jun 25, 2011 at 9:00 AM, Jens Blanck
wrote:
> So there's a range of possible Monoid instances for each type,
More for some types than for others. For Maybe there are three:
On Sat, Jun 25, 2011 at 2:02 PM, Brent Yorgey wrote:
> Actually, there are (at least) four: there's also the one where
> mappend = liftA2 mappend, i.e. introduce potential failure into a
> monoid operation defined on the values. I wrote about it here:
>
> http://byorgey.wordpress.com/2011/04/1
On 6/25/11 1:07 PM, Evan Laforge wrote:
> In the
> case of the overriding version, you have to decide on which side to
> merge the new monoid, and on the lifted one the two choices become
> four, since you then have to decide whether the unionWith argument
> should be flipped or not.
> [...]
> So I
On 6/25/11 12:00 PM, Jens Blanck wrote:
>>> So there's a range of possible Monoid instances for each type,
>>
>> More for some types than for others. For Maybe there are three:
>>
>> * always take the first/left value;
>> * always take the last/right value;
>> * or, use a semigroup operation
On 6/25/11 6:51 AM, John Lato wrote:
> Honestly I'm quite dis-satisfied with the current state of code which
> depends on iteratee/enumerator. It's nearly all written in a very
low-level
> style, i.e. directly writing 'liftI step', or 'case x of Yield -> ...'.
> This is exactly what I would hope
On Fri, Jun 24, 2011 at 11:13:46PM -0700, wren ng thornton wrote:
> On 6/25/11 1:34 AM, Evan Laforge wrote:
> > So there's a range of possible Monoid instances for each type,
>
> More for some types than for others. For Maybe there are three:
>
> * always take the first/left value;
> * always t
On Fri, 24 Jun 2011, Evan Laforge wrote:
So there's a range of possible Monoid instances for each type, and
maybe they were chosen by historical happenstance rather than some
kind of "principle monoid" (is there such a thing?). Is there a name
for the thing that's like a monoid, but the operat
I'm pleased to announce the initial release of Win32-junction-point
* hackage: http://hackage.haskell.org/package/Win32-junction-point
* git repository: https://github.com/mikesteele81/Win32-junction-point
This package provides the ability to manipulate NTFS junction points as
supported by Window
The error in ghci is
Couldn't match expected type `Int' with actual type `[a0]'
In the expression: []
In an equation for `p': p [] = []
You've defined p as [String] -> Int, but then your base case is p [] = []. []
is not an Int. I changed it to 0 and it'll compile, at least, but I'm not
First I am using WinHugs.
that's the code i made so far but it's still not working:
http://hpaste.org/48318
Error:
ERROR file:.\kursovazadacha.hs:36 - Type error in explicitly typed binding
*** Term : p
*** Type : [String] -> [a]
*** Does not match : [String] -> Int
I'm st
On 2011-06-25 10:52, David Mazieres wrote:
> Further confusing things, GHC accepts the following:
>
> g1 x y z = if x>y then show x ++ show z else g2 y x
>
> g2 :: (Show a, Ord a) => a -> a -> String
> g2 | False = \p q -> g1 q p ()
> | otherwise = \p q -> g1 q p 'a
On Sat, Jun 25, 2011 at 19:07, Evan Laforge wrote:
> On Sat, Jun 25, 2011 at 9:00 AM, Jens Blanck wrote:
>>> > So there's a range of possible Monoid instances for each type,
>>>
>>> More for some types than for others. For Maybe there are three:
>>>
>>> * always take the first/left value;
>>> *
On Sat, Jun 25, 2011 at 9:00 AM, Jens Blanck wrote:
> I don't think the original question really is about commutativity, but
> rather the choice of Monoid instance.
Well, it was about two things, and that was one of them :)
>> > So there's a range of possible Monoid instances for each type,
>>
>
Arlen Cuss writes:
>> import Data.Either
>> type (:|:) a b = Either a b
>> (???) = either
>>
>> foo :: (Int :|: Bool :|: String :|: Double) -> Int
>> foo =
>> \ i -> i + 7 ???
>> \ b -> if b then 1 else 0 ???
>> \ s -> length s ???
>> \ d -> floor d
>
> INFIX TYPE OPERATOR
>> So is there a typeclass for that?
>
> There might be one hidden in one of the attempts at redesigning the
> numeric hierarchy (e.g., Numeric Prelude), but there's not a canonical
> typeclass for them. Unfortunately it's not really a good match for the
> typeclass system since it doesn't introduc
I don't think the original question really is about commutativity, but
rather the choice of Monoid instance.
Not being especially mathematically inclined, every once and a while I
> get a little panicked when I notice that, e.g. Data.Map mappend is a
> plain left-biased union, and doesn't actually
Section 4.4.3.2 of the 2010 Haskell report says:
A simple pattern binding has form p = e. The pattern p is
matched “lazily” as an irrefutable pattern, as if there were
an implicit ~ in front of it.
This makes it sound as though p is a pattern, which I assume means
what sec
http://en.wikipedia.org/wiki/File:Haskell-Logo.svg
cheers daniel
Am 6/25/11 8:18 AM, schrieb Michael Xavier:
I wondered if anyone knew the legalities of using the haskell logo, in
particular, this one:
http://media.nokrev.com/junk/haskell-logos/logo1.png
on a website, a personal blog in parti
From: Eric Rasmussen
>
> Hi,
>
> Examples are very helpful to me too -- thank you for sharing. I'm
> especially
> curious to see if there are any examples that allow you to use or convert
> non-iteratee-based functions. I have only just begun reading about
> iteratees
> and might be missing the p
Manuel M T Chakravarty wrote:
> That's right, but it doesn't help any of us anything. The
> costs of defending against a patent claim (even if the claim
> can eventually be overturned) are much to high to bear for
> anybody, but major corporations. In other words, it doesn't
> matter if you are
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