[R-pkg-devel] Linking an R package to the Python library

[Bruce Hoff]

Dear Johannes:
Thank you for sending the link to "pythoninr".  Looking at the page, under
"Windows" there is the statement  "One obviously needs to have R and Python
installed."  Our goal is to create a package which does not require that
the user install Python prior to installing the R package.  The use of
Python should be seamless/invisible to the user.  So pythoninr may be an
interesting alternative to rPython/rPython-win but (based on my read of the
documentation) it doesn't get me closer to the solution of embedding Python
within the R package.
Again, thanks for the reference, which I had not seen previously.
Best,
Bruce Hoff
Sage Bionetworks

On Mon, Feb 29, 2016 at 11:16 PM, Johannes Ranke <jranke at uni-bremen.de>
wrote:

> Bruce,
>
> maybe you want to also have a look at PythonInR, which solves a similar, if
> not the same, problem
>
> https://bitbucket.org/Floooo/pythoninr/
>
> Johannes
>
> Am Montag, 29. Februar 2016, 13:01:06 schrieb Bruce Hoff:
> > I am trying to create a self-contained R package wrapping Python that
> works
> > cross platform and have not been able to do this on Windows.  There is
> > already an R package which calls Python, requiring Python to be installed
> > on the target machine: https://github.com/cjgb/rPython-win.  When the R
> > package is built it successfully links to the resident Python dll.
> >
> > I retrieved the Python source code plus associated Visual Studio projects
> > as described here: https://docs.python.org/devguide/setup.html  I ran
> the
> > Python 3.6 build and verified that rPython-win can link to the generated
> > dll, as expected.  In order to make a portable, self-contained R
> package, I
> > changed the build to create a _static_ Python library as described in the
> > file PCbuild\readme.txt.  This creates a 31MB file "python36.lib" but
> when
> > I try to build the rPython-win package under R i386 (and using the latest
> > RTools) I get:
> >
> > gcc -m32 -shared -s -static-libgcc -o rPython.dll tmp.def pycall.o
> > -LC:/cpython/PCbuild/win32 -lpython3stub -lpython36
> > -Ld:/RCompile/r-compiling/local/local323/lib/i386
> > -Ld:/RCompile/r-compiling/local/local323/lib
> > -LC:/PROGRA~1/R/R-32~1.3/bin/i386 -lR
> > C:/cpython/PCbuild/win32/python36.lib: *error adding symbols: File format
> > not recognized*
> > collect2.exe: error: ld returned 1 exit status
> > no DLL was created
> > ERROR: compilation failed for package 'rPython'
> >
> > I see some mention of the link error here:
> > https://sourceware.org/bugzilla/show_bug.cgi?id=17910
> > It looks like a related bug was in binutils 2.25 on 2/27/2015.  It seems
> > like the fix would have made it into Rtools 3.3 since:
> > 1) this page suggests that the aforementioned was resolved before the
> > latest release of binutils, 2.25.1, 9/15/2015:
> > https://sourceforge.net/projects/mingw/files/MinGW/Base/binutils/
> > 2) Installing Rtools 3.3, one can see that the binaries which are part of
> > binutils (like ld.exe) are dated 9/22/2015.
> >
> > I don't know if MinGW is 'buggy', if I'm doing something wrong, and/or
> what
> > to do to fix the link error.
> >
> > Is there anyone on this list with experience linking an R package to a
> > static library built on Windows using Visual Studio?
> >
> > Any suggestions are appreciated!
> >
> >       [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-package-devel at r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-package-devel
> --
> PD Dr. Johannes Ranke
> Kronacher Str. 8
> 79639 Grenzach-Wyhlen
>

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