Dylan Thurston writes:
:
| (A question in the above context is whether the literal '0' should
| be interpreted as 'fromInteger (0::Integer)' or as 'zero'.
| Opinions?)
Opinions? Be careful what you wish for. ;-)
In a similar discussion last year, I was making wistful noises about
subtyping
Hello
Please help me to solve this questions
Question
Cartesian Product of three sets, written as X x Y x Z is defined as the set
of all ordered triples such that the first element is a member of X, the
second is member of Y, and the thrid member of set Z. write a Haskell
function cartesianPr
Dylan Thurston <[EMAIL PROTECTED]> writes:
> On Wed, Feb 07, 2001 at 01:57:41PM -0500, Dylan Thurston wrote:
> > ... One point that has not been made: given a class
> > setup like
> >
> > then naive users can continue to use (Num a) in contexts, and the same
> > programs will continue to work.
Wed, 7 Feb 2001 16:17:38 -0500, Peter Douglass <[EMAIL PROTECTED]> pisze:
> What I have in mind is to remove division by zero as an untypable
> expression. The idea is to require div, /, mod to take NonZeroNumeric
> values in their second argument. NonZeroNumeric values could be created by
> f
Dylan Thurston wrote:
>
>
> Why doesn't your argument show that all types should by instances of
> Eq and Show? Why are numeric types special?
>
Why do you think it does? I certainly don't think so.
The point about Eq was that a objection was raised to Num being a
subclass of Eq because, for
On Wed, Feb 07, 2001 at 01:57:41PM -0500, Dylan Thurston wrote:
> ... One point that has not been made: given a class
> setup like
>
> then naive users can continue to use (Num a) in contexts, and the same
> programs will continue to work.
I take that back. Instance declarations would change,
On Wed, Feb 07, 2001 at 10:08:26PM +, [EMAIL PROTECTED] wrote:
> - even for me, no great mathematician, I found the forced inclusion of
> certain classes irritating (in my case - effectively implementing
> arithmetic on tuples - Enum made little sense and ordering is hacked
> in order to be to
I have some questions about how Haskell's numeric classes might be
revamped.
Is it possible in Haskell to circumscribe the availability of certain
"unsafe" numeric operations such as div, /, mod? If this is not possible
already, could perhaps a compiler flag "-noUnsafeDivide" could be added to
On Wed, Feb 07, 2001 at 11:47:11AM +0100, Ketil Malde wrote:
> "Ch. A. Herrmann" <[EMAIL PROTECTED]> writes:
[...]
> > the problem is that the --majority, I suppose?-- of mathematicians
> > tend to overload operators. They use "*" for matrix-matrix
> > multiplication as well as for matrix-vector m
Other people have been making great points for me. (I particularly
liked the example of Dollars as a type with addition but not
multiplication.) One point that has not been made: given a class
setup like
class Additive a where
(+) :: a -> a -> a
(-) :: a -> a -> a
negate :: a -> a
zero
07 Feb 2001 11:47:11 +0100, Ketil Malde <[EMAIL PROTECTED]> pisze:
> If it is useful to have a fine granularity of classes, you can
> imagine doing:
>
> class Multiplicative a b c where
> (*) :: a -> b -> c
Then a*b*c is ambiguous no matter what are types of a,b,c and th
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"Ch. A. Herrmann" answers my questions:
> Jerzy> What do you mean "predefined" operators? Predefined where?
>
> In hugs, ":t (*)" tells you:
>(*) :: Num a => a -> a -> a
> which is an intended property of Haskell, I suppose.
Aha. But I would never call this a DEFINITION of this operator
Hi Haskellers,
> "Jerzy" == Jerzy Karczmarczuk <[EMAIL PROTECTED]> writes:
Jerzy> "Ch. A. Herrmann" wrote:
>> the problem is that the --majority, I suppose?-- of
>> mathematicians tend to overload operators. They use "*" for
>> matrix-matrix multiplication as well as for matr
Patrik Jansson wrote:
> [I am not sure a more mathematically correct numeric class system is
> suitable for inclusion in the language specification of Haskell (a
> library would certainly be useful though)]
I think it should be done at the language level.
Previously Brian Boutel wrote:
...
"Ch. A. Herrmann" <[EMAIL PROTECTED]> writes:
> moved to haskell-cafe
No, but *now* it is. (Does haskell@ strip Reply-To? Bad list! Bad!)
> the problem is that the --majority, I suppose?-- of mathematicians
> tend to overload operators. They use "*" for matrix-matrix
> multiplication as well a
moved to haskell-cafe
Ketil> E.g. way back, I wrote a simple differential equation solver.
Ketil> Now, the same function *could* have been applied to vector
Ketil> functions, except that I'd have to decide on how to implement
Ketil> all the "Num" stuff that really didn't fit well.
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