Added note about SWIG (replacing a whole lot of nonsense about how

difficult it is to do).
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Guido van Rossum 1997-04-11 15:19:35 +00:00
parent cb5cf9b186
commit 44adb0c95f
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@ -1866,33 +1866,16 @@ Calling setattr(), to assign to variables in the module, also works.
5.10. Q. How do I interface to C++ objects from Python?
A. Depending on your requirements, there are many approaches. Begin
by reading the "Extending and Embedding" document (Doc/ext.tex, see
also <URL:http://www.python.org/doc/>). Realize that for the Python
run-time system, there isn't a whole lot of difference between C and
C++ -- so the strategy to build a new Python type around a C structure
(pointer) type will also work for C++ objects.
A. Depending on your requirements, there are many approaches. To do
this manually, begin by reading the "Extending and Embedding" document
(Doc/ext.tex, see also <URL:http://www.python.org/doc/>). Realize
that for the Python run-time system, there isn't a whole lot of
difference between C and C++ -- so the strategy to build a new Python
type around a C structure (pointer) type will also work for C++
objects.
Automatic generation of interfaces between Python and C++ is still at
the horizon -- parsing C++ header files requires an almost complete
C++ parser, and many features aren't easily translated from C++ to
Python: certain forms of operator oveloading, function overloading
(best approached by a varargs function which explicitly type-checks
its arguments), and reference arguments are just a number of features
that are hard to translate correctly if at all.
The hardest problem is to transparently translate the C++ class
hierarchy to Python, so that Python programs derive classes from C++
classes. Given suitable constraints, this may be possible, but it
would require more space than I have in this FAQ to explain how.
In any case, you can get quite a bit done without this, using just the
existing classes from Python.
If this all seems rather daunting, that may be because it is -- C++
isn't exactly a baby to handle without gloves! However, people have
accomplished amazing feats of interfacing between Python and C++, and
a detailed question posted to the Python list is likely to elicit some
interesting and useful responses.
A useful automated approach (which also works for C) is SWIG:
http://www.cs.utah.edu/~beazley/SWIG/.
6. Python's design