Hi. I was just curious about something. In one of my math textbooks I
see expressions like this
f + g
or
(f + g)(a)
where f and g are functions. What is meant is
f(a) + g(a)
Is there a way in Haskell you can make use of syntax like that (i.e.,
expressions like f + g and f * g to create a n
Might not be exactly what you're looking for, but Control.Arrow has a rich
set of operators that can be used to combine functions.
For instance, there's an example on
http://en.wikibooks.org/wiki/Haskell/Understanding_arrows showing an addA
function that can be used to apply two functions to the s
Yes, you can do that, but you probably shouldn't.
See also:
http://www.haskell.org/haskellwiki/Num_instance_for_functions
http://hackage.haskell.org/package/applicative-numbers
On Sat, Aug 31, 2013 at 10:01 PM, Christopher Howard <
christopher.how...@frigidcode.com> wrote:
> Hi. I was just cur
* Christopher Howard [2013-08-31
21:01:38-0800]
> Hi. I was just curious about something. In one of my math textbooks I
> see expressions like this
>
> f + g
>
> or
>
> (f + g)(a)
>
> where f and g are functions. What is meant is
>
> f(a) + g(a)
>
> Is there a way in Haskell you can make us
To clarify in Bobs remark : while you're still learning Haskell and the
type system , things like lifted Num on functions can lead to some
potentially confusing type errors.
That said, it's absolutely doable, and can be a very nice / powerful tool
when used appropriately.
On Sunday, September 1,
On 08/31/2013 09:27 PM, Charlie Paul wrote:
I believe that this is what you want:
http://www.haskell.org/haskellwiki/Num_instance_for_functions
On Sat, Aug 31, 2013 at 10:01 PM, Christopher Howard
wrote:
The author seemed to be subtly mocking the idea. It seemed to be
suggesting that a Num i
On 1/09/2013, at 7:06 PM, Christopher Howard wrote:
> It seemed to be suggesting that a Num instance for functions would imply the
> need for constant number functions, which leads to difficulties. But I don't
> see why one would have to take it that far.
You *cannot* make a type an instance of