With the latest master I still get "ERROR: syntax: malformed type parameter
list".
Possibly I was not clear (I was actually going to clarify, but I
accidentally hit 'post' prematurely...). Note that the second type
parameter is `n::Integer` rather than `n<:Integer`, in other words, I want
specify that the `n` parameter must be a value rather than a type, so that
`FixedArray{Int,3}` allowed, but not `FixedArray{Int,Int}`
An application of this might be to allow dispatch on the contents of a
Val{T}. A trivial example to illustrate the idea:
function f{T::Int}(::Type{Val{T}})
-T
end
function f{T::Bool}(::Type{Val{T}})
!T
end
So that f(Val{1}) and f(Val{true}) call different methods. Currently you
can use a @generated function to check the type T, but then you could not
later add methods to f that handle values of T with types other than Int
and Bool.
Tom
On Wednesday, 30 September 2015 11:48:58 UTC+10, Tim Holy wrote:
>
> Yes, the syntax you proposed already works. Try it out.
>
> --Tim
>
> On Tuesday, September 29, 2015 06:42:36 PM Tom Lee wrote:
> > Is there any way to restrict a type parameter to a particular bitstype,
> or
> > is this planned in the next type design iteration? eg:
> >
> > type FixedVector{T<:Number, n::Integer}
> > data::NTuple{n,T}
> > end
> >
> >
> > You can achieve this by adding checks in the constructor, but doing so
> > always makes things so untidy.
>
>
