rprint and IO about rcall.jl

[randy3k]

I have implemented something similar in the RCalling.jl. Check https://github.com/randy3k/RCalling.jl/blob/master/src/sexp.jl#L28

[simonbyrne]

Ah, great thanks!

[randy3k]

Just one more thing, my code does not capture STDERR, we should also do redirect_stderr!? (Somehow I have a feeling that the STDERR of R is re-directed to the STDOUT.)

EDIT:
I also discovered that the warning messages never print. They should be printed when a rprint function is triggered.

julia> using RCall

julia> rcall(:warning, "it is a warning");

julia> rprint("1")
[1] 1

[simonbyrne]

On my machine they appear at the end of the Julia session.

julia> using RCall

julia> rcall(:warning,"hello")
StrSxp(536870992,Ptr{Void} @0x00007fb514770978,Ptr{Void} @0x00007fb5191af5c8,Ptr{Ptr{None}} @0x00007fb5191af5f0,1,0)

julia>  quit()
Warning message:
hello 

[simonbyrne]

I've changed the IO, and fixed the warning problem in #59

[simonbyrne]

Looks like i was too ambitious: Rf_PrintWarnings doesn't work on linux (it's an unsupported function, but seems to work fine on Windows and OS X). Apparently we're not the only ones who want this, but it doesn't look like the r-dev team are in a hurry to fix it.