Similar_type for Vector

New to Julia
1

So I have a variable v which may take several types, including (at least) Vector{T}, SVector{N,T}, where N is an integer and T is a real type (including at least Int, Rational{Int} and Float64). I want to compute a type similar to v but with element type promoted to some other type Q.

In the case of SVector, the following works: similar_type(v, Q). However, no method is implemented when v is a plain old Vector.

I could override this by defining StaticArrays.similar_type(::Vector, T::Type) = Vector{T} (or, even better, a more general method, although this one does what I want), but this although this feels like fixing something which should have been done, it is still technically type-piracy. Since this is too trivial to reasonably have been an oversight in StaticArrays.jl: is there a good reason why this package does not define similar_type methods for plain Array types?

2

Isn’t this sort of what similar(v, Q) should do? Or do you require a stricter type match?

3

similar(v, Q) returns a value; I want a type. Of course, I could call typeof(similar(v,Q)) or even first(Base.return_types(similar,Tuple{typeof(v),Type{Q}})), but the first solution would (probably) allocate an array, while the second is completely inelegant.

4

The latter is certainly not the right answer as it’s not required to return the narrowest match