RE: deriving Typeable
You can just write the instance of Typeable by hand
instance Typeable1 e = Typeable (Y e) where ...
(Use the instances in the library as a guide.)
Yes, GHC could do this for you, but it would then stumble when e had kind ((*-*) -
*). We need kind polymorphism!
Simon
| -Original Message-
| From: [EMAIL PROTECTED] [mailto:glasgow-haskell-users-
| [EMAIL PROTECTED] On Behalf Of John Meacham
| Sent: 02 June 2004 21:53
| To: [EMAIL PROTECTED]
| Subject: deriving Typeable
|
| newtype Y e = Y { unY :: (e (Y e)) }
| deriving(Data,Typeable,Show,Read,Eq)
|
| gives
| E.hs:64:
| Can't make a derived instance of `Typeable (Y e)'
| (`Y' is parameterised over arguments of kind other than `*')
| When deriving instances for type `Y'
|
| Is there any way around this limitation other than manually expanding Y
| everywhere I want to use it (which I really don't want to do)? Is the
| limitation inherent to the way Typeable works, or is it just that no one
| has implemented it yet?
|
| --
| John Meacham - repetae.netjohn
| ___
| Glasgow-haskell-users mailing list
| [EMAIL PROTECTED]
| http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
___
Glasgow-haskell-users mailing list
[EMAIL PROTECTED]
http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: F#
In article [EMAIL PROTECTED], Manuel M T Chakravarty [EMAIL PROTECTED] wrote: Generally, phrases such as XYZ is excellent within certain niches sounds like cheap propaganda to me. If you replace Haskell by Linux, I am sure you'll find similar statements on other Microsoft web pages ;-) Doubtless. I think if they're casting about for excuses not to use Haskell, they're unlucky not to have hit on time/space issues. Anyway, I've rewritten it for them: Purely functional languages like Haskell are excellent to write in, but non-trivial work is involved with implementing a lazy language in a strict run-time environment. ... -- Ashley Yakeley, Seattle WA ___ Glasgow-haskell-users mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Parallel
Hello. I am a newcomer to functional programming, and I would like to learn it very much. However, I'm also starting to deal with parallel programming, and I thought I'd combine my two interests. So I grabbed the Debian ghc6 package (v6.2), and (after a lot of searching) found out that I lack the mp way. Then I tried grabbing the sources, and compiling them with WAYS=mp, but when the compiler is compiling the mp way, it does so with the -parallel switch, which requires the mp include files - the very ones I am trying to compile! Now, several people tried telling me that GpH is a separate project, but 1) it's very out of date 2) ghc source has a ton of PVM references 3) the ghc user manual mentions parallel code ...so I kind of figured that GpH got integrated into ghc. The problem is that I just can't get it to run! Can anyone tell me what I am doing wrong? Goran Topic ___ Glasgow-haskell-users mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
