open_toontown_panda3d/dtool/src/interrogate

A key advantage of Panda3D is that it provides developers with the ability to use both C++ and Python simultaneously. Essentially, Panda3D gives programmers the best of both worlds, as they are able to take advantage of the high performance and low-level programming found in C++ in addition to the flexibility, interactive scripting, and rapid-prototyping capabilities of Python. This feature is made possible due to Python’s ability to call C libraries, and ultimately make use of Panda3D’s Interrogate System: an automated C++ Extension Module generation utility similar to SWIG. Although Python is the favored scripting language of Panda3D, the engine is highly extensible in this aspect, as any language that has a foreign function interface can make use of the Interrogate System.

The Interrogate System works like a compiler by scanning and parsing C++ code for the Panda3D-specific, “PUBLISHED” keyword. This keyword marks the particular methods of a class that are to be exposed within a C++ Extension Module for that class which is eventually generated. One benefit of using the “PUBLISHED” keyword is that it alleviates the need for an interface file that provides function prototypes for the class methods that will be exposed within the extension module, as is the case with SWIG. Interrogate turns a class into a loose collection of Python interface wrapper functions that make up the C++ Extension Module.

This package depends on the 'cppparser' package, which contains the code that parses the C++ headers, and the 'interrogatedb' package, which contains the intermediate representation of the interfaces that can be saved to a database file for FFI generation tools to consume.