Below are corrections of embarassing mistakes in my examples, pointed out by
Wolfram and Stefan Holdermans.
On Tue, Jan 11, 2005 at 11:12:04PM +0100, Tomasz Zielonka wrote:
> before:
>
> case t of
> (x, y, z) -> (x, y, z+1)
>
> after:
>
> case t of
> (_, _, ctx @> z) -> ctx z
On Wed, Jan 12, 2005 at 01:02:43AM +0100, Stefan Holdermans wrote:
> Furthermore, I think with this syntax, it is just too easy to get
> wrong. Maybe I'm mistaken, but, to illustrate, I believe there's even
> an error in the very examples given by you:
>
> >after:
> >
> > case t of
> > (_
On Tue, Jan 11, 2005 at 06:30:02PM -0500, Stefan Monnier wrote:
> > case t of
> > (x, y, z) -> (x, y, z+1)
>
> How would you do:
>
> case t of
> (x, y, z, a, b, c) -> (x+1, y, z, a, b, c+2)
>
> would you allow:
>
> case t of
> (ctx @> x, _, _, _, _, ctx @> c) ->
Tomasz Zielonka <[EMAIL PROTECTED]>
proposed an interesting kind of ``second-order as-patterns''
that are ``safe'' from the usual problems of second-order matching
by virtue of fixing (at least) the spine
of the images of the second-order variables.
Tomasz' first example (incorporating Stefan Hold
Tomasz,
I have an idea for a funny extension to pattern matching in Haskell. I
wonder
if it was proposed before, and most importantly, if it would be seen
as useful.
I haven't seen anything like this before, which if of course not to say
that there has never been made a similar proposal before.
> case t of
> (x, y, z) -> (x, y, z+1)
How would you do:
case t of
(x, y, z, a, b, c) -> (x+1, y, z, a, b, c+2)
would you allow:
case t of
(ctx @> x, _, _, _, _, ctx @> c) -> ctx (x+1) (c+2)
-- Stefan
___
Haskell mai
Hello!
I have an idea for a funny extension to pattern matching in Haskell. I wonder
if it was proposed before, and most importantly, if it would be seen as useful.
Currently, pattern variables get only the values of the corresponding subterms
of a matched term. What if we could mark a pattern va
Hi,
> I can't understand how constraints float at all. In the following code:
>
Ex1:
> > class Foo1 a where foo1 :: a -> String
> > class Foo2 a where foo2 :: a -> String
> >
> > instance Foo1 Bool where foo1 _ = "Bool"
> > instance Foo2 Char where foo2 _ = "Char"
> >
> > data U a wh
