Use generator scripts to automatically create Python bindings

[kloudkl]

As more and more interfaces are exposed in Python manually, it is not only hard to keep the Python and C++ API in sync but also introduce bugs and performance issues on the Python side. It would be nice to be able to automatically generate the Python scripts. OpenCV does this in a clear and clean way.

[shelhamer]

I actually take issue with this. The C++ interface is not a naturally Pythonic interface in and of itself and I like the control of developing our own interface and exporting well-formed classes instead of bare functions. @longjon, agreed?

[jeffdonahue]

I'm not @longjon, but I do agree. The interfaces really just need a few unit tests; I think those would go a long way to improve maintainability. (Even just a Python script that Travis can run that does import caffe would be a pretty useful start -- we currently don't even have a way of automatically checking that changes to the wrapper modules are syntactically valid, which indeed makes maintenance and reviewing changes a painfully manual process IMO.)

[longjon]

I am @longjon, and I agree with most everything said in this thread. There is a certain amount of boilerplate involved in the Python interface, and it's a good idea to keep in mind the tools that might help alleviate that. That said, the bindings do enough extra magic that it's hard to imagine automatically generating very much of the existing code, and the bindings are sufficiently few that the overhead of generation would certainly exceed the current overhead of maintenance. (Also, there have been no performance issues with the bindings proper, only with pure Python code.)

And yes, testing the Python interface is the real pressing issue. Hopefully the next merge to pycaffe will be for testing, even if it is just an import or just runs the basic interface.

[futurely]

Unit test frameworks are inherent parts of Python and MATLAB.

[futurely]

Add unit test for the Python and MATLAB wrappers is not a novel issue. #173 has been open for a long time.