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git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk/SWIG@9206 626c5289-ae23-0410-ae9c-e8d60b6d4f22
138 lines
3.3 KiB
HTML
138 lines
3.3 KiB
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<title>SWIG and R</title>
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<link rel="stylesheet" type="text/css" href="style.css">
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</head>
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<body bgcolor="#ffffff">
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<H1><a name="R_nn1"></a>32 SWIG and R</H1>
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<!-- INDEX -->
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<div class="sectiontoc">
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<ul>
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<li><a href="#R_nn2">Bugs</a>
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<li><a href="#R_nn3">Using R and SWIG</a>
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<li><a href="#R_nn4">General policy</a>
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<li><a href="#R_nn5">Language conventions</a>
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<li><a href="#R_nn6">C++ classes</a>
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<li><a href="#R_nn7">Enumerations</a>
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</ul>
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</div>
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<!-- INDEX -->
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<p>
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R is a GPL'ed open source statistical and plotting environment.
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Information about R can be found at <a
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href="http://www.r-project.org/">www.r-project.org</a>.
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The R binding are under active development and are extremely
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experimental. Not all features have been implemented and the API is
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not stable.
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</p>
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<H2><a name="R_nn2"></a>32.1 Bugs</H2>
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<p>
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Currently the following features are not implemented or broken:
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</p>
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<ul>
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<li>Garbage collection of created objects
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<li>C Array wrappings
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<li>tested on UNIX only, how well or badly it works on windows is not known
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</ul>
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<H2><a name="R_nn3"></a>32.2 Using R and SWIG</H2>
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<p>
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To use R and SWIG in C mode, execute the following commands where
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example_func.c is the name of the file with the functions in them
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</p>
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<div class="shell">
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<pre>
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swig -r -o example,c example.i
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PKG_LIBS="example_func.c" R CMD SHLIB example.c
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</pre>
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</div>
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<p>
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The corresponding comments for C++ mode are
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</p>
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<div class="shell">
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<pre>
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swig -c++ -r -o example.cpp example.i
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PKG_LIBS="example_func.cxx" R CMD SHLIB example.cpp
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</pre>
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</div>
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<p>
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Note that R is sensitive to the name of the file and to the file
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extension in C and C++ mode. The name of the wrapper file must be the
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name of the library. Also in C++ mode, the file extension must be cpp
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rather than cxx for the R compile command to recognize it.
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</p>
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<p>
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The commands produce two files. A dynamic shared object file called
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example.so and an R wrapper file called example_wrap.S. To load these
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files, start up R and type in the following commands
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</p>
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<div class="shell">
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<pre>
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dyn.load('example.so')
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source('example_wrap.S')
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</pre>
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</div>
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<p>
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These two files can be loaded in any order
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</p>
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<H2><a name="R_nn4"></a>32.3 General policy</H2>
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<p>
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The general policy of the module is to treat the C/C++ as a basic
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wrapping over the underlying functions and rely on the R type system
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to provide R syntax.
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</p>
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<H2><a name="R_nn5"></a>32.4 Language conventions</H2>
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<p>
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getitem and setitem use C++ conventions (i.e. zero based indices). [<-
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and [ are overloaded to allow for R syntax (one based indices and
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slices)
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</p>
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<H2><a name="R_nn6"></a>32.5 C++ classes</H2>
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<p>
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C++ objects are implemented as external pointer objects with the class
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being the mangled name of the class. The C++ classes are encapsulated
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as an SEXP with an external pointer type. The class is the mangled
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name of the class. The nice thing about R is that is allows you to
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keep track of the pointer object which removes the necessity for a lot
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of the proxy class baggage you see in other languages.
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</p>
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<H2><a name="R_nn7"></a>32.6 Enumerations</H2>
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<p>
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enumerations are characters which are then converted back and forth to
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ints before calling the C routines. All of the enumeration code is
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done in R.
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</p>
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</body>
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</html>
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