I had it pretty well worked out for single parameter type classes, but I
couldn't see any nice extension to multiple parameters.
On Dec 11, 2007 5:30 PM, Simon Peyton-Jones <[EMAIL PROTECTED]> wrote:
> | If it really would work ok we should get it fully specified and
> | implemented so we can fix
Simon Peyton-Jones wrote:
Concerning (b) here's a suggestion. As now, require that every instance
requires an instance declaration. So, in the main example of
http://haskell.org/haskellwiki/Class_system_extension_proposal, for a new data
type T you'd write
instance Monad T where
Simon Peyton-Jones wrote:
Given "instance C T where ...", for any method 'm' not
defined by "...":
for every class D of which C is a superclass
where there is an instance for (D T)
see if the instance gives a binding for 'm'
If this search finds exactly one bin
On Dec 11, 2007 1:29 PM, apfelmus <[EMAIL PROTECTED]> wrote:
> Without the automatic search, this is already possible
>
> class Functor f where
> fmap :: (a -> b) -> f a -> f b
>
> class Functor m => Monad m where
> return :: a -> m a
> (>>=) :: m a -> (a -> m b) -
Simon Peyton-Jones wrote:
b) having instance declarations silently spring into existence
Concerning (b) here's a suggestion. As now, require that every instance
requires an instance declaration. So, in the main example of
http://haskell.org/haskellwiki/Class_system_extension_proposal, for a n
| If it really would work ok we should get it fully specified and
| implemented so we can fix the most obvious class hierarchy problems in a
| nice backwards compatible way. Things are only supposed to be candidates
| for Haskell' if they're already implemented.
Getting it fully specified is the f
On Tue, 2007-12-11 at 16:38 +, Ross Paterson wrote:
> On Tue, Dec 11, 2007 at 04:26:52PM +, Simon Marlow wrote:
> > Duncan Coutts wrote:
> >> On Tue, 2007-12-11 at 07:07 -0800, Stefan O'Rear wrote:
> >>> This is almost exactly the
> >>> http://haskell.org/haskellwiki/Class_system_extension
On Tue, Dec 11, 2007 at 04:26:52PM +, Simon Marlow wrote:
> Duncan Coutts wrote:
>> On Tue, 2007-12-11 at 07:07 -0800, Stefan O'Rear wrote:
>>> This is almost exactly the
>>> http://haskell.org/haskellwiki/Class_system_extension_proposal; that
>>> page has some discussion of implementation issu
Duncan Coutts wrote:
On Tue, 2007-12-11 at 07:07 -0800, Stefan O'Rear wrote:
This is almost exactly the
http://haskell.org/haskellwiki/Class_system_extension_proposal; that
page has some discussion of implementation issues.
Oh yes, so it is. Did this proposal get discussed on any mailing list
On Tue, 2007-12-11 at 07:07 -0800, Stefan O'Rear wrote:
> This is almost exactly the
> http://haskell.org/haskellwiki/Class_system_extension_proposal; that
> page has some discussion of implementation issues.
Oh yes, so it is. Did this proposal get discussed on any mailing list?
I'd like to see
On Dec 11, 2007 9:20 AM, Duncan Coutts <[EMAIL PROTECTED]> wrote:
> So my suggestion is that we let classes declare default implementations
> of methods from super-classes.
Does this proposal have any unintended consequences? I'm not sure.
> Please discuss :-)
It creates ambiguity if two class
On Tue, Dec 11, 2007 at 02:20:52PM +, Duncan Coutts wrote:
> I'd just like to float an idea that's related to the Class Alias
> proposal[1] but is perhaps somewhat simpler.
>
> We all know that Functor should have been a superclass of Monad, and
> indeed we now know that Applicative should be
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