Using CondaPkg with R Packages

[ParadaCarleton]

I'm not sure if this is possible, but if it is, it would be nice to include a brief tutorial showing how to use CondaPkg.jl with RCall.jl.

[frankier]

I have given some information on my current workaround here: JuliaInterop/RCall.jl#480

[cjdoris]

Such a tutorial probably belongs with RCall not with CondaPkg. However I'll happily add links to "upstream tutorials" (on RCall/PythonCall/etc) to the README.

[frankier]

Sounds reasonable. I will try to do that as a next step after getting this PR merged which should make the integration more straight forward.

[frankier]

@ParadaCarleton

I wonder whether you might be able to help test this? If you are able to test/review it might help with getting PRs merged.

The first step is to try this PR from RCall: JuliaInterop/RCall.jl#496

pkg> add "https://github.com/frankier/RCall.jl.git#preferences-r-installation"

The second is to run this (you will have to add Libdl + PreferenceTools to your project for now)

using CondaPkg
using Preferences
using Libdl
using PreferenceTools

function locate_libR(Rhome)
    @static if Sys.iswindows()
        libR = joinpath(Rhome, "bin", Sys.WORD_SIZE==64 ? "x64" : "i386", "R.dll")
    else
        libR = joinpath(Rhome, "lib", "libR.$(Libdl.dlext)")
    end
    return libR
end

CondaPkg.resolve()
target_rhome = "$(CondaPkg.envdir())/lib/R"
PreferenceTools.add(
    "RCall",
    "Rhome" => target_rhome,
    "libR" => locate_libR(target_rhome)
)

e.g. put it in a file setup_rcondapkg.jl and run as part of your top level project julia --project=. setup_rcondapkg.jl. Then you should be able to add this to CondaPkg.toml

[deps]
r-mypkg = ""
r = ""

The second step is a bit annoying but I guess it should be possible to streamline it to some extent e.g. adding an extension package to RCall.jl.