When using RCall from Julia embedded in R, things like R REPL mode are not set up.

[Non-Contradiction]

I'm currently developing an R package JuliaCall which aims at embedding julia in R. https://github.com/Non-Contradiction/JuliaCall

And in the init() function of setup.jl of RCall, there is something like this:

if !Rinited
   ...................
    # R gui eventloop
    isinteractive() && rgui_init()
    # R REPL mode
    isdefined(Base, :active_repl) &&
        isinteractive() && typeof(Base.active_repl) != Base.REPL.BasicREPL &&
            RPrompt.repl_init(Base.active_repl)
end

Since julia is already embedded in R, Rinited is true, and the code for REPL mode will not be executed. So if I want to use R REPL mode provided by RCall, I have to RCall.RPrompt.repl_init(Base.active_repl) myself like this:

Is there any reason for not doing rgui_init() and setting REPL mode when R is already started besides not doing repetitive work? Could we use other ways to check whether R REPL mode is set and gui_init() has been done?

[randy3k]

You are probably correct. Would you submit the PR?

[randy3k]

It is an interesting project.

Btw, I am on the master branch of JuliaCall and it does not seem to be working for me.

EDIT: works now after running julia_setup()

[Non-Contradiction]

Yes, I' m going to submit a PR, although I'm not quite familiar with the julia workflow of developing packages.

[Non-Contradiction]

Sorry the screenshot is not complete. julia_setup() needs to use first to do some setup like this:

library(JuliaCall)
julia <- julia_setup()
julia_console()

[randy3k]

I figured it out. Amazing package.

[randy3k]

I also realized I could embedde julia in an R session embedded in julia.

julia> using RCall
WARNING: Method definition ==(Base.Nullable{S}, Base.Nullable{T}) in module Base at nullable.jl:238 overwritten in module NullableArrays at /Users/Randy/.julia/v0.6/NullableArrays/src/operators.jl:99.

julia> R"library(JuliaCall); julia_setup(); julia_console()"
WARNING: RCall.jl: Julia at location /Applications/Julia-0.6.app/Contents/Resources/julia/bin will be used.
Julia version 0.6.0 found.
Julia initiation...
Finish Julia initiation.
Loading setup script for JuliaCall...
Finish loading setup script for JuliaCall.
               _
   _       _ _(_)_     |  A fresh approach to technical computing
  (_)     | (_) (_)    |  Documentation: https://docs.julialang.org
   _ _   _| |_  __ _   |  Type "?help" for help.
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 0.6.0 (2017-06-19 13:05 UTC)
 _/ |\__'_|_|_|\__'_|  |  Official http://julialang.org/ release
|__/                   |  x86_64-apple-darwin13.4.0

julia>

Though, arguably, it is useless.

[randy3k]

I reckon that we could use

any(:prompt in fieldnames(m) && m.prompt == "R> " for m in mirepl.interface.modes)

to check if the repl has been initilaized.

[Non-Contradiction]

Yes, it works. Although it seems that I need to do more work on the JuliaCall side. In my test, using RCall in julia_console() won't trigger RCall.__init__(), which is kind of strange. I probably should using RCall on the startup of julia_console() and do the setup.

[randy3k]

It is expected that using RCall does not trigger RCall.__init__(). It is common to have multiple using RCall statements in a Julia session, __init__() will only be triggered when a package is loaded first time.

[randy3k]

You may also need to run rgui_start and rgui_stop() before and after julia_console().

[randy3k]

You could just execute RCall.__init__() in the setup.jl.

[Non-Contradiction]

When JuliaCall sources setup.jl in embedded julia, julia is not in the interactive use. So even RCall.__init__() explicitly, things like REPL won't set up. Do I understand correctly?

[randy3k]

Ai, you are correct. In fact, we shouldn't call __init__() explicitly. It may break other things.

Perhaps, you should just execute repl_init() when ! repl_inited().