I constantly run into cases where triangular dispatch would be very useful
in our work.
Ever since Jeff's talk at JuliaCon 2015, I've been hoping for the improved
type system work (which seemed fairly complete, with working code in
examples).
Any hope of that making it into v0.5? If not, what issues are holding it
back?
On Friday, April 29, 2016 at 5:56:43 AM UTC-4, Milan Bouchet-Valat wrote:
>
> Le vendredi 29 avril 2016 à 00:06 -0700, DNF a écrit :
> > I was going to suggest:
> >
> > type MyType{A<:AbstractArray, T<:Unsigned}
> > data::A{T}
> > end
> >
> > which does not work. The error is:
> > ERROR: TypeError: Type{...} expression: expected Type{T}, got TypeVar
> >
> > Does anyone know whether this should work in an ideal world, or does
> > the type definition simply not make sense?
> This is called triangular dispatch, and will likely be supported at
> some point. See https://github.com/JuliaLang/julia/issues/3766 and the
> issues linked there.
>
>
> Regards
>
> > > Hi, I'm tying to create a parametric type which can hold a variable
> > > which could be any kind of vector, and whatever the vector is, it
> > > can store one of the UInts. So it could have:
> > >
> > > UInt8[1,2,3]
> > > UInt64[1,2,3]
> > > UnitRange(1, 3)
> > > UnitRange(UInt16(1), UInt16(3))
> > > ... and so on.
> > >
> > > But I'm having trouble deciding what needs to go in the parametric
> > > part of it's definition: e.g.
> > >
> > > MyType{T <: (unsure of this bit)}
> > > val::T
> > > end
> > >
> > >
> > > I thought that AbstractVector{Unsigned} might be the way to go, but
> > > Vector{UInt8} does not inherit from AbstractVector{Unsigned}.
> > >
> > > Thanks,
> > > Ben.
> > >
>
