It’s already possible to call Julia from R (as other have suggested for package development), and done, and note also RCall.jl for calling in other direction, with its R mode.
Note also:
And upcoming juliac
compiler will likely make this even more compelling, but it’s strictly not needed, current tools good enough.
I think everything is handled with this dual Julia/Python binding package
That PythonCall package is of course Python specific, but it relies on CondaPkg.jl which isn’t. I’m not sure, maybe, probably, it helps for R users installing Julia dependencies?