Martin Rubey wrote:
> Martin Rubey <[email protected]> writes:
>
> > Rep := PositiveInteger -> Coef
> >
> > which is however caching values. Or maybe I should just forget about
> > the caching?
>
>
> As a follow up - is the following sensible? (it does work)
>
> The only thing that would be affected is the way the user coerces
> functions into the DirichletRing. Actually, I think I like it...
>
> (4) -> g: PI -> INT := n +-> n
>
> (4) -> g 1
>
> (4) 1
>
> (5) -> g::HI(INT)
>
> (5) 1
> Type: HiThere(Integer)
> (7) -> h(n: PI): INT == n+1783
> Function declaration h : PositiveInteger -> Integer has been added
> to workspace.
> 1 old definition(s) deleted for function or rule h
> Type: Void
> (8) -> h::HI(INT)
> Compiling function h with type PositiveInteger -> Integer
>
> (8) 1784
> Type: HiThere(Integer)
>
>
> )abb package HI HiThere
> HiThere(Coef: SetCategory): SetCategory with
> coerce: (PositiveInteger -> Coef) -> %
> == add
> FUN ==> PositiveInteger -> Coef
> Rep := FUN
>
> per(a: Rep): % == a pretend %
> rep(a: %): Rep == a pretend Rep
>
> coerce(f: FUN): % == per f
>
> coerce(a: %): OutputForm ==
> f: FUN := a pretend FUN
> x: Coef := f(1$PositiveInteger)
> x::OutputForm
>
Remarks:
- I am not sure what you gain compared to Mapping
- Coercion to OutputForm looks fishy.
- you need some way to evaluate the functions (using
'pretend' every time you wnat to evaluate is ugly)
- without caching you will be recomputing values multiple
times which may be as bad (or worse) as comuting all
values once.
--
Waldek Hebisch
[email protected]
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