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.
"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.
This
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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 the
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 :: a
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
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
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
