Easy-to-use macro?

Just wondering if anybody would be interested in the following macro @bkamins @markmbaum?

A function would be fine too of course; it just feels a bit more appropriate as a macro due to the behavior as both an operation on types and on instances.

macro readonly(expr)
    esc(:($(_readonly)($expr)))
end
_readonly(::Type{A}) where {T,N,A<:AbstractArray{T,N}} = ReadOnlyArray{T,N,A}
_readonly(ar::AbstractArray) = ReadOnlyArray(ar)

The use-cases are as follows:

julia> @readonly Vector{UInt8}
ReadOnlyArray{UInt8, 1, Vector{UInt8}}

julia> @readonly Array{Float32, 3}
ReadOnlyArray{Float32, 3, Array{Float32, 3}}

julia> @readonly [1, 2, 3]
3-element ReadOnlyArray{Int64, 1, Vector{Int64}}:
 1
 2
 3

I've got it as an internal macro but I could just upstream it here if interested.

Start by reviewing the proposed Julia @readonly macro and its _readonly dispatches. Check the existing ReadOnlyArray API and examples for type and array inputs, then add coverage showing both forms produce the demonstrated results.