Extend macros with rand to support custom samplers

[mateuszbaran]

Fixes #804 .

[hyrodium]

Thanks for the PR!

julia> using StaticArrays

julia> @SVector rand(1:5, 3)
3-element SVector{3, Int64} with indices SOneTo(3):
 1
 4
 4

julia> @macroexpand @SVector rand(1:5, 3)
:(StaticArrays._rand((StaticArrays.Random).GLOBAL_RNG, 1:5, StaticArrays.Size(3), (SVector){3}))

It works fine for the original issue, but I have some questions about the implementation.

• How can we create SizedArray version of rand(1:5, 3)?
• How can we create something like @SVector rand(rng, 1:5, 3)? (x-ref: Error when @SMatrix randn(rng,ComplexF64,(2,2)) #1019 (comment))

These are why I proposed strand function in the comment. (#804 (comment))

[mateuszbaran]

• How can we create SizedArray version of rand(1:5, 3)?

I'd just do SizedVector{3}(rand(1:5, 3)).

• How can we create something like @SVector rand(rng, 1:5, 3)? (x-ref: Error when @SMatrix randn(rng,ComplexF64,(2,2)) #1019 (comment))

These are why I proposed strand function in the comment. (#804 (comment))

I don't see this PR as a full replacement of strand, just a quick fix for the most commonly requested use case. If you want to work on strand, I can review your PR.

[hyrodium]

Could you please also update @SArray and @MArray macros? Other parts LGTM!

[mateuszbaran]

Could you please also update @SArray and @MArray macros? Other parts LGTM!

Sure. When working on it, I had an idea for supporting passing rng as well. What do you think?

[hyrodium]

Great!!:rocket: But I found some degression.

Before this PR

julia> using StaticArrays

julia> @SArray rand(3)
3-element SVector{3, Float64} with indices SOneTo(3):
 0.3872905952155763
 0.9519315858388775
 0.42729797815514925

After this PR

julia> using StaticArrays

julia> @SArray rand(3)
ERROR: LoadError: BoundsError: attempt to access 2-element Vector{Any} at index [3]
Stacktrace:

If we can handle rng in @SArray, it would be nice to have these features in @SVector and @SMatrix.

[mateuszbaran]

OK, I think I've fixed that issue and also added rng support to SVector and SMatrix.