Brian Boutel [EMAIL PROTECTED] writes:
The fact that equality can be trivially defined as bottom does not imply
that it should be a superclass of Num, it only explains that there is an
ugly way of working around the problem.
There is nothing trivial or ugly about a definition that reflects
Marcin 'Qrczak' Kowalczyk wrote:
JK Now, signum and abs seem to be quite distincts beasts. Signum seem
JK to require Ord (and a generic zero...).
Signum doesn't require Ord.
signum z = z / abs z
for complex numbers.
Thank you, I know. And I ignore it. Calling "signum" the result of
Brian Boutel wrote:
William Lee Irwin III wrote:
The Standard Prelude serves its purpose well and accommodates the
largest cross-section of users. Perhaps a Geek Prelude could
accommodate the few of us who do need these sorts of schenanigans.
Amen.
Aha.
And we will have The
Fri, 9 Feb 2001 11:48:33 -0500, Dylan Thurston [EMAIL PROTECTED] pisze:
class (Show a, Read a, Eq a) = Comfortable a
instance (Show a, Read a, Eq a) = Comfortable a
Why isn't it legal?
Because in Haskell 98 instance's head must be of the form of a type
constructor applied to type
On Fri, Feb 09, 2001 at 12:05:09PM -0500, Dylan Thurston wrote:
On Thu, Feb 08, 2001 at 04:06:24AM +, Marcin 'Qrczak' Kowalczyk wrote:
You can put Num a in some instance's context, but you can't
put Convertible Integer a. It's because instance contexts must
constrain only type
Fri, 09 Feb 2001 10:52:39 +, Jerzy Karczmarczuk pisze:
Again, a violation of the orthogonality principle. Needing division
just to define signum. And of course a completely different approach
do define the signum of integers. Or of polynomials...
On Fri, Feb 09, 2001 at 07:19:21PM +,
Ketil Malde wrote:
Brian Boutel [EMAIL PROTECTED] writes:
- Having a class hierarchy at all (or making any design decision)
implies compromise.
I think the argument is that we should move Eq and Show *out* of the
Num hierarchy. Less hierarchy - less compromise.
Can you demonstrate
Another Haskell - Haskell transformation tool which I always thought
would be useful (and perhaps exists?) would be a Haskell de-moduleizer.
Basically it would take a Haskell program and follow its imports and
spit out a single monolithic Haskell module. My first thought is that
this should be
On 08-Feb-2001, Dylan Thurston [EMAIL PROTECTED] wrote:
On Thu, Feb 08, 2001 at 09:41:56PM +1100, Fergus Henderson wrote:
One point that needs to be resolved is the interaction with default methods.
Consider
class foo a where
f :: ...
f = ...
On 08-Feb-2001, Marcin 'Qrczak' Kowalczyk [EMAIL PROTECTED] wrote:
I don't like the idea of treating the case "no explicit definitions
were given because all have default definitions which are OK"
differently than "some explicit definitions were given".
I don't really like it that much
On 09-Feb-2001, Brian Boutel [EMAIL PROTECTED] wrote:
Patrik Jansson wrote:
The fact that equality can be trivially defined as bottom does not imply
that it should be a superclass of Num, it only explains that there is an
ugly way of working around the problem.
...
There is nothing
Sat, 10 Feb 2001 14:09:59 +1300, Brian Boutel [EMAIL PROTECTED] pisze:
Can you demonstrate a revised hierarchy without Eq? What would happen to
Ord, and the numeric classes that require Eq because they need signum?
signum doesn't require Eq. You can use signum without having Eq, and
you can
12 matches
Mail list logo
