I like the name RCall. Maybe you could have an R module inside of RCall, so you can use R.plot, R.sum, and bring in as much as possible without worrying about namespaces.
Also, you might want to use the PyCall code and general interface for guidance. On Fri, Jan 2, 2015 at 2:59 PM, Douglas Bates <[email protected]> wrote: > For many statistics-oriented Julia users there is a great advantage in > being able to piggy-back on R development and to use at least the data sets > from R packages. Hence the RDatasets package and the read_rda function in > the DataFrames package for reading saved R data. > > Over the last couple of days I have been experimenting with running an > embedded R within Julia and calling R functions from Julia. This is similar > in scope to the Rif package except that this code is written in Julia and > not as a set of wrapper functions written in C. The R API is a C API and, > in some ways, very simple. Everything in R is represented as a "symbolic > expression" or SEXPREC and passed around as pointers to such expressions > (called an SEXP type). Most functions take one or more SEXP values as > arguments and return an SEXP. > > I have avoided reading the code for Rif for two reasons: > 1. It is GPL3 licensed > 2. I already know a fair bit of the R API and where to find API function > signatures. > > Here's a simple example > julia> initR() > 1 > > julia> globalEnv = unsafe_load(cglobal((:R_GlobalEnv,libR),SEXP),1) > Ptr{Void} @0x0000000008c1c388 > > julia> formaldehyde = tryEval(install(:Formaldehyde)) > Ptr{Void} @0x0000000008fd1d18 > > julia> inherits(formaldehyde,"data.frame") > true > > julia> printValue(formaldehyde) > carb optden > 1 0.1 0.086 > 2 0.3 0.269 > 3 0.5 0.446 > 4 0.6 0.538 > 5 0.7 0.626 > 6 0.9 0.782 > > julia> length(formaldehyde) > 2 > > julia> names(formaldehyde) > 2-element Array{ASCIIString,1}: > "carb" > "optden" > > julia> form1 = ccall((:VECTOR_ELT,libR),SEXP,(SEXP,Cint),formaldehyde,0) > Ptr{Void} @0x000000000a5baf58 > > julia> ccall((:TYPEOF,libR),Cint,(SEXP,),form1) > 14 > > julia> carb = > copy(pointer_to_array(ccall((:REAL,libR),Ptr{Cdouble},(SEXP,),form1),length(form1))) > 6-element Array{Float64,1}: > 0.1 > 0.3 > 0.5 > 0.6 > 0.7 > 0.9 > > julia> form2 = ccall((:VECTOR_ELT,libR),SEXP,(SEXP,Cint),formaldehyde,1) > Ptr{Void} @0x000000000a5baef0 > > julia> ccall((:TYPEOF,libR),Cint,(SEXP,),form2) > 14 > > julia> optden = > copy(pointer_to_array(ccall((:REAL,libR),Ptr{Cdouble},(SEXP,),form2),length(form2))) > 6-element Array{Float64,1}: > 0.086 > 0.269 > 0.446 > 0.538 > 0.626 > 0.782 > > > A call to printValue uses the R printing mechanism. > > Questions: > - What would be a good name for such a package? In the spirit of PyCall > it could be RCall or Rcall perhaps. > > - Right now I am defining several functions that emulate the names of > functions in R itself ir in the R API. What is a good balance? Obviously > it would not be a good idea to bring in all the names in the R base > namespace. On the other hand, those who know names like "inherits" and > what it means in R will find it convenient to have such names in such a > package. > > - Should I move the discussion the the julia-stats list? > >
