Thank your for this elaborate explanation, you made my day!
Thomas
Ryan Ingram wrote:
On Mon, Aug 17, 2009 at 12:12 AM, Thomas van Noorttho...@cs.ru.nl wrote:
Somehow I didn't receive David's mail, but his explanation makes a lot of
sense. I'm still wondering how this results in a type error
: 18 August 2009 21:56
| To: Thomas van Noort
| Cc: Haskell Cafe
| Subject: Re: [Haskell-cafe] Type family signatures
|
| On Mon, Aug 17, 2009 at 12:12 AM, Thomas van Noorttho...@cs.ru.nl wrote:
| Somehow I didn't receive David's mail, but his explanation makes a lot of
| sense. I'm still wondering
On Mon, Aug 17, 2009 at 12:12 AM, Thomas van Noorttho...@cs.ru.nl wrote:
Somehow I didn't receive David's mail, but his explanation makes a lot of
sense. I'm still wondering how this results in a type error involving rigid
type variables.
rigid type means the type has been specified by the
Somehow I didn't receive David's mail, but his explanation makes a lot
of sense. I'm still wondering how this results in a type error involving
rigid type variables.
Ryan Ingram wrote:
On Fri, Aug 14, 2009 at 12:03 PM, Dan Westonweston...@imageworks.com wrote:
But presumably he can use a
Hello,
I have a question regarding type family signatures. Consider the
following type family:
type family Fam a :: *
Then I define a GADT that takes such a value and wraps it:
data GADT :: * - * where
GADT :: a - Fam a - GADT (Fam a)
and an accompanying unwrapper:
unwrap ::
On Fri, Aug 14, 2009 at 11:06 AM, Thomas van Noorttho...@cs.ru.nl wrote:
Hello,
I have a question regarding type family signatures. Consider the following
type family:
type family Fam a :: *
Then I define a GADT that takes such a value and wraps it:
data GADT :: * - * where
GADT ::
But presumably he can use a data family instead of a type family to
restore injectivity, at the cost of adding an extra wrapped bottom value
and one more layer of value constructor?
David Menendez wrote:
On Fri, Aug 14, 2009 at 11:06 AM, Thomas van Noorttho...@cs.ru.nl wrote:
Hello,
I have
On Fri, Aug 14, 2009 at 12:03 PM, Dan Westonweston...@imageworks.com wrote:
But presumably he can use a data family instead of a type family to restore
injectivity, at the cost of adding an extra wrapped bottom value and one
more layer of value constructor?
Actually, you don't even necessarily
