Re: Audit Parsing Library Requirements

Steve Grubb <sgrubb(a)redhat.com&gt; writes: Cool. I looked at both the SWIG and Python/C API, and then realized that I sit just two doors down from Sam Bayer. He has made extensive use of these tools, and here is what I learned from talking with him. (1) Even if you plan to only support Python as the scripting language, use SWIG to generate as much of the interface as you can, because it automatically generates a lot of Python/C API code for you. (2) Even if you plan to specify your interfaces only in SWIG, become familiar with the Python/C API so you can read the generated code. Sam found important errors by carefully reading generated code. Memory management issues become obvious by reading the code. (3) It is very simple to use SWIG if the only objects that are passed across the language boundary are numbers, strings, and opaque pointers. (4) Sam avoided passing structures, preferring to define classes in pure Python code, and using a function interface to implement methods of the class. The SWIG document suggests structures can be used, and appear as a class in Python. I think Sam likes the idea of a thin interface, and passing a structure is too heavy-weight for his tastes. (5) One can pass functions in both directions, and Sam described all the details to me that is involved with passing and invoking a Python function in C. In this case, one cannot use SWIG. My reading is Steve is unlikely to define an interface that passes either C or Python functions, so these difficulties can be ignored. So read the SWIG 1.3 Basics Chapter, and then flip to the chapter on Python, and along with the Python/C API document, you should be able access the information you need. John