On 1/9/12 7:54 AM, Luminous Fennell wrote:
On Mon, Jan 09 2012 at 10:37 +0100, Steve Horne wrote:
On 08/01/2012 21:13, Brandon Allbery wrote:
(Also, de facto I think it's already more or less been decided in
favor of type families, just because functional dependencies are (a)
a bit alien
On 08/01/2012 20:25, Brent Yorgey wrote:
On Fri, Jan 06, 2012 at 10:51:58AM +, Steve Horne wrote:
If I specify both extensions (-XMultiParamTypeClasses and
-XFlexibleInstances) it seems to work, but needing two language
extensions is a pretty strong hint that I'm doing it the wrong way.
On 08/01/2012 21:13, Brandon Allbery wrote:
(Also, de facto I think it's already more or less been decided in
favor of type families, just because functional dependencies are (a) a
bit alien [being a glob of Prolog-style logic language imported into
the middle of System Fc] and (b) [as I
Hi,
On Mon, Jan 09 2012 at 10:37 +0100, Steve Horne wrote:
On 08/01/2012 21:13, Brandon Allbery wrote:
(Also, de facto I think it's already more or less been decided in
favor of type families, just because functional dependencies are (a)
a bit alien [being a glob of Prolog-style logic
On Fri, Jan 06, 2012 at 10:51:58AM +, Steve Horne wrote:
If I specify both extensions (-XMultiParamTypeClasses and
-XFlexibleInstances) it seems to work, but needing two language
extensions is a pretty strong hint that I'm doing it the wrong way.
Not necessarily. These two extensions in
On Sun, Jan 8, 2012 at 9:25 PM, Brent Yorgey byor...@seas.upenn.edu wrote:
On Fri, Jan 06, 2012 at 10:51:58AM +, Steve Horne wrote:
If I specify both extensions (-XMultiParamTypeClasses and
-XFlexibleInstances) it seems to work, but needing two language
extensions is a pretty strong
On Sun, Jan 8, 2012 at 15:55, Christoph Breitkopf
chbreitk...@googlemail.com wrote:
On Sun, Jan 8, 2012 at 9:25 PM, Brent Yorgey byor...@seas.upenn.eduwrote:
On Fri, Jan 06, 2012 at 10:51:58AM +, Steve Horne wrote:
If I specify both extensions (-XMultiParamTypeClasses and
I was messing around with type-classes (familiarization exercises) when
I hit a probably newbie problem. Reducing it to the simplest case...
module BinTree ( WalkableBinTree, BT (Branch, Empty) ) where
-- n : node type
-- d : data item type wrapped in each node
class WalkableBinTree n
On 01/06/2012 11:16 AM, Steve Horne wrote:
I was messing around with type-classes (familiarization exercises) when
I hit a probably newbie problem. Reducing it to the simplest case...
module BinTree ( WalkableBinTree, BT (Branch, Empty) ) where
-- n : node type
-- d : data item type wrapped
On 06/01/2012 10:29, Steffen Schuldenzucker wrote:
On 01/06/2012 11:16 AM, Steve Horne wrote:
I was messing around with type-classes (familiarization exercises) when
I hit a probably newbie problem. Reducing it to the simplest case...
module BinTree ( WalkableBinTree, BT (Branch, Empty) )
On 01/06/2012 11:51 AM, Steve Horne wrote:
On 06/01/2012 10:29, Steffen Schuldenzucker wrote:
On 01/06/2012 11:16 AM, Steve Horne wrote:
[...]
module BinTree ( WalkableBinTree, BT (Branch, Empty) ) where
-- n : node type
-- d : data item type wrapped in each node
class WalkableBinTree n
-cafe@haskell.org
Subject: Re: [Haskell-cafe] Simple type-class experiment turns out not so
simple...
On 06/01/2012 10:29, Steffen Schuldenzucker wrote:
With 'd' not being mentioned anywhere, the signature of wbtData means
forall d. n - Maybe d. In particular, wbtData == const Nothing
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