ffi_doc.txt

This document specifies how the ffi is used.

the statement:
	#load ./my_ffi.so

loads the shared object my_ffi. This uses dlopen
so paths should be specified with that in mind.

foreign lib::funcname (args)

calls the function funcname from the lib shared object.


Foreign libraries are written in cpp and should be compiled with
	g++ -shared mylib.cpp -o mylib.so

As dlopen is used, all functions you wish to be available should
be marked with extern "C" to avoid name mangling.

Exposed functions are given a std::vector of pointers to Objects, 
defined in object.hpp.  The vector can be considered to be the functions 
stack frame and contains the objects passed to the callee. The last 
element of t his vector is the object that will be returned from 
the function; if the call frame is empty null(Unit) is returned instead.

TODO: pinning objects and other GC concerns.