Yes, it's possible, but it's rather painful.
Here is my working attempt, written to be compatible with GHC 7.6.3. Better
ones may be possible, but I'm doubtful.
> {-# LANGUAGE TemplateHaskell, RankNTypes, TypeFamilies, TypeOperators,
> DataKinds, ScopedTypeVariables, GADTs, PolyKind
Anyone here from the Nashville, TN area? t would be nice to meet
regularly with others to discuss and work with Haskell. Also, this
group is now available:
www.meetup.com/The-Haskell-Study-Group/
If you want to participate remotely, that works too, I'm just looking
for others to meet with regular
* Anthony Cowley [2013-10-12 15:43:57-0400]
>
> On Oct 12, 2013, at 2:47 PM, Niklas Hambüchen wrote:
> >
> > I would like to come back to the original question:
> >
> > How can ordNub be added to base?
> >
> > I guess we agree that Data.List is the right module for a function of
> > type Ord
On 12/10/13 20:43, Anthony Cowley wrote:
> I think nub's behavior is rather set-related, so I don't really understand
> the objection to putting it in Data.Set.
In sets, the order does not matter, while for nub it does.
nub:: Eq a => [a] -> [a]
ordNub :: Ord a => [a] -> [a]
both do
On Oct 12, 2013, at 2:47 PM, Niklas Hambüchen wrote:
>
> I would like to come back to the original question:
>
> How can ordNub be added to base?
>
> I guess we agree that Data.List is the right module for a function of
> type Ord a => [a] -> [a], but this introduces
>
> * a cyclic dependency
I would like to come back to the original question:
How can ordNub be added to base?
I guess we agree that Data.List is the right module for a function of
type Ord a => [a] -> [a], but this introduces
* a cyclic dependency between Data.List and Data.Set
* a base dependency on containers.
What i
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 t
Hello everyone,
I'm still trying to resolve my problem. I try to restate it in a simpler
way.
Is it possible to write extract and update functions for L ?
import Data.Nat
data family X (n::Nat) :: *
data L (n::Nat) where
Q :: L (Succ n) -> X n -> L n
E :: L n
extract :: L Zero -> X n
e
