Andrew J Bromage [EMAIL PROTECTED] writes:
class Plus a b c | a b - c where
(+) :: a - b - c
class Mult a b c | a b - c where
(*) :: a - b - c
This kind of approach was discussed a while ago, and has a bunch of
things to recommend it. Is the functional
G'day all.
On Fri, Jul 11, 2003 at 04:28:19PM -0400, Dylan Thurston wrote:
Don't be silly [...]
Never!
Cheers,
Andrew Bromage
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On 2003-07-12 at 20:20+1000 Andrew J Bromage wrote:
G'day all.
On Fri, Jul 11, 2003 at 04:28:19PM -0400, Dylan Thurston wrote:
Don't be silly [...]
Never!
Or only sometimes. I'm surprised that no-one has yet
answered the question How overload operator in Haskell?
with Overload operator
answered the question How overload operator in Haskell?
with Overload operator in Haskell fine. (cf Cary Grant)
I am also surprised at this, it can be done by C++ .
--
J? Fairbairn [EMAIL PROTECTED]
31 Chalmers Road [EMAIL
On Thu, 10 Jul 2003 10:58:51 +1000, Andrew J Bromage [EMAIL PROTECTED]
wrote:
This suggests that wrapping each standard mathemtaical
function/operator in its own typeclass would have literally
no run-time performance penalty:
class Plus a b c | a b - c where
(+) :: a - b - c
On Fri, Jul 11, 2003 at 05:38:18PM +1000, Andrew J Bromage wrote:
G'day all.
On Thu, Jul 10, 2003 at 11:16:56PM -0700, Ashley Yakeley wrote:
As written, this is _not_ a good idea. Trust me, you end up having to
put type annotations everywhere. Even (3 + 4 :: Integer) is ambiguous,
In article [EMAIL PROTECTED],
Glynn Clements [EMAIL PROTECTED] wrote:
instance Num Vector where
Except that class instances have to be algebraic datatypes (data) or
renamed datatypes (newtype), but not type synonyms (type).
That's not true, is it? I mean as long as there isn't already
In article [EMAIL PROTECTED],
Andrew J Bromage [EMAIL PROTECTED] wrote:
This suggests that wrapping each standard mathemtaical
function/operator in its own typeclass would have literally
no run-time performance penalty:
class Plus a b c | a b - c where
(+) :: a - b - c
fre 2003-07-11 klockan 08.07 skrev Ashley Yakeley:
In article [EMAIL PROTECTED],
Glynn Clements [EMAIL PROTECTED] wrote:
instance Num Vector where
Except that class instances have to be algebraic datatypes (data) or
renamed datatypes (newtype), but not type synonyms (type).
G'day all.
On Thu, Jul 10, 2003 at 11:16:56PM -0700, Ashley Yakeley wrote:
As written, this is _not_ a good idea. Trust me, you end up having to
put type annotations everywhere. Even (3 + 4 :: Integer) is ambiguous,
you have to write (3 :: Integer) + (4 :: Integer).
But that's what
I've learned haskell months, but I still can't understand the type system very well.
I can only write:
---
type Vector = [Double]
vadd,vsub :: Vector-Vector-Vector
v1 `vadd` v2 = zipWith (+) v1 v2
v1 `vsub` v2 = zipWith (-) v1 v2
svmul :: Double-Vector-Vector
s
-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Liu Junfeng
Sent: Wednesday, July 09, 2003 7:25 AM
To: [EMAIL PROTECTED]
Subject: How overload operator in Haskell?
I've learned haskell months, but I still can't understand the
type system very well.
I can only write
Hal Daume answers a question on how to define nice, infix ops
acting on vectors:
What you want to do is make your Vector an instance of the Num(eric)
type class. For instance:
instance Num Vector where
(+) v1 v2 = zipWith (+) v1 v2
(-) v1 v2 = zipWith (-) v1 v2
negate v1 = map negate v1
PROTECTED]
Subject: Re: How overload operator in Haskell?
While this is a possible solution, I would shout loudly: Arrest this
man, he
is disrespectful wrt math!. Actually, this shows once more that the Num
class
and its relatives is a horror...
Signum in this context has no sense. The multiplication
On Wednesday, 2003-07-09, 17:11, CEST, Hal Daume wrote:
What you want to do is make your Vector an instance of the Num(eric) type
class.
It would be better to define one's own operators instead of using + and -
because Vector has no meaningful instance of Num (as Jerzy Karczmarczuk
already
G'day all.
On Wed, Jul 09, 2003 at 05:25:20PM +0200, Jerzy Karczmarczuk wrote:
While this is a possible solution, I would shout loudly: Arrest this man,
he is disrespectful wrt math!. Actually, this shows once more that the Num
class and its relatives is a horror...
Yup.
I recently
Hal Daume wrote:
What you want to do is make your Vector an instance of the Num(eric)
type class. For instance:
instance Num Vector where
Except that class instances have to be algebraic datatypes (data) or
renamed datatypes (newtype), but not type synonyms (type).
--
Glynn Clements
I've learned haskell months, but I still can't understand the type system very well.
I can only write:
---
type Vector = [Double]
vadd,vsub :: Vector-Vector-Vector
v1 `vadd` v2 = zipWith (+) v1 v2
v1 `vsub` v2 = zipWith (-) v1 v2
svmul :: Double-Vector-Vector
s
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