* On Wednesday, April 14 2010, Jesper Louis Andersen wrote:
newtype Process a b c = Process (ReaderT a (StateT b IO) c)
deriving (Functor, Monad, MonadIO, MonadState b, MonadReader a)
Note that the automatic derivations of *MonadState b* and *MonadReader a* makes
GHC spit our some
* On Sunday, May 02 2010, Alexander Dunlap wrote:
Of course, there are situations where it is really awkward to not use
partial functions, basically because you *know* that an invariant is
satisfied and there is no sane course of action if it isn't. To take a
contrived example:
f ys = let xs =
On Tue, May 4, 2010 at 12:18 PM, HASHIMOTO, Yusaku nonow...@gmail.com wrote:
This library is inspired by HList[2], and interfaces are stealed from
data-accessors[3]. And lenses[4], fclabels[5], and records[6] devote
themselves to similar purposes.
[2]: http://hackage.haskell.org/package/HList
On Thu, May 13, 2010 at 7:16 PM, HASHIMOTO, Yusaku nonow...@gmail.com wrote:
Sorry for spamming, what I wanted to write is I think `has' has better
interface than other record packages in types.
There are many libraries to write function takes an record has Foo
and Bar and returns something.
* On Monday, June 09 2008, Duncan Coutts wrote:
And - is there a way to make GHCi use aliased qualification? I find
my self typing detailed taxonomies all the time there.
The ghci syntax currently is:
:m Data.Set
wouldn't it be much nicer as:
import Data.Set
then we could have the obvious:
* On Thursday, June 19 2008, Ketil Malde wrote:
As a side note, may I advise you to use another symbol, and leave the
poor dot alone? Overloading it as a module separator is bad enough.
If you have a keyboard that allows greater-than-ascii input, there are
plenty of options: « » ¡ £ ¥ ł € ® ª...
This is most likely attributable to the use of different compilers.
I don't see how accepting such a variant can cause ambiguity, but I'm
not quite sure whether it is legal H98.
On 5/6/09, Magnus Therning mag...@therning.org wrote:
Brandon S. Allbery KF8NH wrote:
On May 6, 2009, at 12:18 ,
* On Saturday, December 13 2008, Gianfranco Alongi wrote:
I have actually been thinking about a similar thing, but on the group
subject.
One can actually group things in many ways, such as groupBy (==) , so
that groupBy (==) [1,2,1,2] should give
[[1,1],[2,2]]. Of course other ideas are
* On Monday, February 16 2009, Andrew Coppin wrote:
I do have one little question. Let me see if I can find the quote... Ah,
here we go:
The WrappedMonad and WrappedArrow constructors witness the fact that
any Monad and any Arrow can be made into an Applicative.
I don't really
This seems to be in ghc for those reasons:
http://www.haskell.org/haskellwiki/Quasiquotation
* On Monday, March 02 2009, Andrew Hunter wrote:
Several times now I've had to define an EDSL for working with
(vaguely) numeric expressions. For stuff like 2*X+Y, this is easy,
looking pretty much
On Sat, Nov 24, 2012 at 1:32 AM, Erik de Castro Lopo
mle...@mega-nerd.com wrote:
Hi all,
It seems the Quasiquotation page on HaskellWiki
http://www.haskell.org/haskellwiki/Quasiquotation
has fallen behind the actually Quasiquotation implementation that
is in ghc-7.4.2 and later.
On Wed, Dec 5, 2012 at 12:12 AM, Takayuki Muranushi muranu...@gmail.com wrote:
Dear everyone,
I have a code
https://github.com/nushio3/practice/blob/master/instance-inference/zipf-11-1.hs
that produces a type-error when I remove a type signature.
On Sat, Dec 8, 2012 at 10:27 AM, Takayuki Muranushi muranu...@gmail.com wrote:
Continued discussion from
https://groups.google.com/d/topic/haskell-cafe/-e-xaCEbd-w/discussion
https://groups.google.com/d/topic/haskell-cafe/kM_-NvXAcx8/discussion
Thank you for all the answeres and thinkings;
On Mon, Dec 10, 2012 at 7:23 PM, Takayuki Muranushi muranu...@gmail.com wrote:
Repeated thanks to you, Adam! Your code is brilliantly simple.
Sadly, I cannot reproduce the behaviors in your comments on my ghci
(7.6.1) .
Can we guess why? The version of packages we are using?
Mines are
On Sat, Dec 15, 2012 at 9:24 AM, satvik chauhan mystic.sat...@gmail.com wrote:
Yeah, that is the problem. I have a function inside which I need to generate
some declarations using TH. I can not generate these at the top level as
these generations depend on the function's parameters which are
a = LongDec a Int a a a Char
Regards,
Adam Vogt
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On Sun, Dec 30, 2012 at 10:00 PM, Brandon Allbery allber...@gmail.com wrote:
On Sun, Dec 30, 2012 at 8:42 PM, Dan Burton danburton.em...@gmail.com
wrote:
[featureX] is usually too powerful, it surely would be abused
extensively, which would make developer's life a nightmare, unless there is
On Fri, Feb 22, 2013 at 12:44 PM, Corentin Dupont
corentin.dup...@gmail.com wrote:
Hi all,
I have a program able to read another program as a string, and interpret it
(using Hint).
I'd like to make unit tests, so I have a file Test.hs containing a serie
of test programs as strings.
However,
Cheers,
Adam Vogt
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Hi Aleksandar,
This library for extensible records does use -XDataKinds:
http://hackage.haskell.org/package/vinyl. It doesn't have as many
definitions as HList, but that might be because more recent extensions
are more powerful. Many other libraries are listed
On Thu, May 30, 2013 at 8:17 PM, Frerich Raabe ra...@froglogic.com wrote:
Hi,
I'm considering to convert one of my projects to Shake; everything I've seen
so far seemed really interesting!
However, before I start, I'd like to see how other people structure their
Shake-based build systems.
On Sun, Jun 2, 2013 at 10:19 PM, Ting Lei tin...@gmail.com wrote:
Thanks for your answers so far.
It seems that the laziness of String or [char] is the problem.
My question boils then down to this. There are plenty of Haskell FFI
examples where simple things like sin/cos in math.h can be
On Mon, Jul 1, 2013 at 5:42 PM, TP paratribulati...@free.fr wrote:
So what is the difference between lift and [||]?
Although I feel stupid, I cannot lie and claim I have understood.
Hi TP,
Sometimes [| |] does need to call lift. If for some reason the
original lift wasn't exported, you could
On Wed, Jul 3, 2013 at 2:25 AM, Magicloud Magiclouds
magicloud.magiclo...@gmail.com wrote:
Then I got
Illegal variable name: `UserPassword'
When splicing a TH declaration:
Hi Magicloud,
GHC seems to be trying to tell you that variables are lowercase in
haskell. Since you don't have code,
On Fri, Jul 19, 2013 at 5:19 AM, Jose A. Lopes jabolo...@google.com wrote:
Hello,
How to define equality for Data.Dynamic ?
Hi Jose,
You could try casting the values to different types that do have an
(==). You can treat the case where you have the types matching, but
didn't list that type
On Sat, Jul 20, 2013 at 12:31 AM, Carter Schonwald
carter.schonw...@gmail.com wrote:
the tricky part then is to add support for other types.
another approach to existentially package type classes with the data type!
eg
data HasEq = forall a . HasEq ( Eq a = a)
or its siblinng
data HasEq a
On Sat, Jul 20, 2013 at 12:14 AM, Michael Orlitzky mich...@orlitzky.com wrote:
For posterity, I report failure =)
Hi Michael,
It's fairly straightforward to generate the new data with template
haskell [1], and on the same page, section 10.7 'generic' zipWith is
likely to be similar to your
on the R side
back to haskell.
Regards,
Adam Vogt
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On Mon, Aug 19, 2013 at 5:40 AM, AntC anthony_clay...@clear.net.nz wrote:
...
Would double-parens be too wild an idea?:
... ((CustId 47)) `extend` (CustName Fred, Gender Male)
f ((CustId x)) = ...
instance C ((CustId Int)) ...
We'd have to avoid the double parens as in:
On Tue, Aug 20, 2013 at 5:00 PM, David Fox d...@seereason.com wrote:
This file gives me the error Cycle in type synonym declarations Can
anyone tell me why? I'm just trying to write a function to create a
type that is a FooT with the type parameter fixed.
{-# LANGUAGE TemplateHaskell #-}
On Sat, Aug 24, 2013 at 11:00 AM, TP paratribulati...@free.fr wrote:
that has type Stmt, in an ExpQ that seems to be the only thing that we can
put in a splice. I have found that it can only be done by doE (or DoE) and
compE (or CompE) according to
Hi Jose and Richard,
haskell-src-meta has Language.Haskell.Meta.Utils.normalizeT which can
help with making code treat the two constructs equivalently, though
I imagine using th-desugar instead will make that process harder to
mess up.
Adam
On Thu, Aug 29, 2013 at 10:13 AM, Richard Eisenberg
Hi TP,
You can add another instance to cover the case that everything is zero.
Then you don't need the :. Also it's convenient to arrange for the
a,b,c to be the argument to Tensor, as given below:
class Multiplication a b c | a b - c where
(*) :: Tensor a - Tensor b - Tensor c
instance
On Sun, Sep 22, 2013 at 11:07 AM, TP paratribulati...@free.fr wrote:
My misunderstanding came from a confusion between a context and a
constraint. The context is what is before the =, and the constraint is
what is after, i.e. the main part of the instance declaration.
Hi TP,
I think context
On Sat, Sep 28, 2013 at 1:09 PM, Ryan Newton rrnew...@gmail.com wrote:
Hi all,
We all know and love Data.Foldable and are familiar with left folds and
right folds. But what you want in a parallel program is a balanced fold
over a tree. Fortunately, many of our datatypes (Sets, Maps)
On Sun, Oct 6, 2013 at 6:54 PM, Tillmann Rendel
ren...@informatik.uni-marburg.de wrote:
Hi,
Ryan Newton wrote:
It is very hard for me to
see why people should be able to make their own Generic instances (that
might lie about the structure of the type), in Safe-Haskell.
I guess that
Hi Luke,
It seems like you missed this module:
http://hackage.haskell.org/package/QuickCheck-2.6/docs/Test-QuickCheck-Gen.html
Adam
On Mon, Oct 7, 2013 at 7:21 PM, Luke Evans l...@eversosoft.com wrote:
I was hoping I could use Arbitrary instances to generate streams of values
for test data.
Hi Paolino,
There are some functions similar to that in HList (Data.HList.HArray).
Check the repo http://code.haskell.org/HList for a version that uses
more type families / gadts.
Maybe there is a way to take advantage of the fact that you've
labelled the elements of the list, but extract isn't
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