Hi,
I am having trouble with Show and tuples.
I have a data structure, say:
data MyData = ...
And a value, say:
value = (MyData..., MyData..., MyData)
Then try to:
show value
I get a compiler message from ghc 4.05 that says:
No instance for `Show (MyData, MyData, MyData)...
What is the b
I have a very simple question. What is the best way to
convert a float to a double?
I use fromRational.toRational, and the notes in the prelude
seem to imply that this is optimized into something sensible..
is this the way?
Cheers! + Ron Legere
Sun, 7 May 2000 16:13:46 +0400 (MSD), S.D.Mechveliani <[EMAIL PROTECTED]> pisze:
> Also what do you do with
> class Foo a where weightOfType :: Int
> ?
In this case one solution is to have a sample argument, because Haskell
does not provide more convenient way of parame
George writes:
> There is no problem with Showing functions with finite domains.
> For example, try:
> module ShowFun where
> instance (Show a) => Show (Bool -> a) where
>show f = show ((f True),(f False))
> instance (Show a) => (Show (Int -> a))
Why stop there? Eq and Read too, though the
Dear Haskell folks,
There's a web server written in Haskell running on haskell.org:
http://www.haskell.org:8080/
Please surf on over and press reload a few times. First one to bring it
down gets a gold star. I'll be watching the logs :-)
The source (not properly packaged, just source
> * I find it difficult to understand how the code I write translates
> into actual algorithms, memory management, etc. Haskell is such a
> nice language that it hides all this detail from me :-). So, I'd be
> grateful for a reference or two on this area.
Manuel pointed out Simon's paper on the
> Why are type constructors and classes in the same namespace?
Because otherwise the syntax
module M ( T ) where
would be ambiguous. I suppose it could be resolved to mean "export the
class and/or data type T". It was proposed for Haskell 98 that the syntax
be changed to
mo
S.D.Mechveliani ([EMAIL PROTECTED]) wrote:
[I cc'd this to haskell as well]
: this is exactly the Domain conversion proposal, described in
: basAlgPropos. class Cast a b where cast :: a -> b -> a.
: The first argument is the sample for domain. The second casts to
: `a' after the given sample
Marc Van Dongen
writes about the need of constant :: a -> b ->
and explains that it is needed, for example, to convert constant
to polynomial.
I consider this as kind of support for the
Domain conversion proposal in basAlgPropos, section 'dcon'.
It suggests
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Sorry about this. I thought I group replied when
replied Sergey's e-mail.
--
Marc van Dongen, CS Dept | phone: +353 21 4903578
University College Cork, NUIC | Fax:+353 21 4903113
College Road, Cork, Ireland | Email: [EMAIL PROTECTED]
- Forwarded message from Marc van Dongen <[EM
S.D.Mechveliani ([EMAIL PROTECTED]) wrote:
: I wrote to list, and you reply privately.
Ooops. I thought I group replied. I'll forward to
the list.
: I think that it is good for the list to know that someone else
: appreciates the need of dynamic parameters in domain ...
Which is why I decided
I wrote on Fergus's example with Alfred, Betty ...
type T a = T ...
instance Additive (T a) where
(T x)+(T y) = T (x+y)
...
It should be data T a ...
instance Additive a
Fergus Henderson <[EMAIL PROTECTED]> writes:
Also one writes, for example, zero x
instead of zero `asTypeOf` x.
> `asTypeOf` is effectively a builtin language construct that just
> happens to be implemented as a function in the s
Concerning the sample argument approach,
Marc van Dongen <[EMAIL PROTECTED]> writes on May 8 2000
> I am not sure if I understand this but I also used
> zero :: a -> a
> to create polynomials as opposed to a function
> zero :: a
> The application
> zero p
> created a zero polynomial with certa
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