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 take the last/right value;
* or, use a semigroup operation defined on the
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 particular. While I am not yet a primarily
haskell coder, I'm using it more and more. I find this logo in particular
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
From: Eric Rasmussen ericrasmus...@gmail.com
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
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
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
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 introduce any
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
Arlen Cuss cel...@sairyx.org 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 OPERATORS!!??!
On Sat, Jun 25, 2011 at 9:00 AM, Jens Blanck jens.bla...@gmail.com 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
On Sat, Jun 25, 2011 at 19:07, Evan Laforge qdun...@gmail.com wrote:
On Sat, Jun 25, 2011 at 9:00 AM, Jens Blanck jens.bla...@gmail.com 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
On 2011-06-25 10:52, David Mazieres wrote:
Further confusing things, GHC accepts the following:
g1 x y z = if xy 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'
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
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
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
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
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 take the
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 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 defined on the
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 think
On Sat, Jun 25, 2011 at 2:02 PM, Brent Yorgey byor...@seas.upenn.edu 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:
On 6/25/11 2:15 PM, Erik Hesselink wrote:
On Sat, Jun 25, 2011 at 19:07, Evan Laforgeqdun...@gmail.com wrote:
On Sat, Jun 25, 2011 at 9:00 AM, Jens Blanckjens.bla...@gmail.com
wrote:
So there's a range of possible Monoid instances for each type,
More for some types than for others. For
At Sat, 25 Jun 2011 14:20:52 -0400,
Scott Turner wrote:
g1 x y z = if xy 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
g1 x y z = if xy 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. According to 4.5.1 and 4.5.2, g1
On Sat, Jun 25, 2011 at 10:18 PM, wren ng thornton w...@freegeek.orgwrote:
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
At Sun, 26 Jun 2011 00:17:12 +0100,
Paterson, Ross wrote:
g1 x y z = if xy 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
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 signature
-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
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
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