Wrapping Ruby around OLD code

ruby-talk
1

E S <eero.saynatkari@kolumbus.fi> Wrote:

Lähettäjä: gw <gw@citasystems.com>
5 years ago one of our smart guys suggested we throw away our home grown

"Basic" which glues our
[SNIP]

As long as the main manipulation of the data structures
happens in C, the following would apply:

Instead of actually mapping the datatypes to Ruby, you can simply
wrap them inside opaque Ruby objects and pass them around that way.
Say you've defined a Ruby class 'MyData' (which in Ruby C is a
variable, traditionally c_MyData):

// You'd normally call this in your C code
extern void do_something(struct whatever * ptr);

#include 'ruby.h'

// VALUE is the basic Ruby type in C
VALUE make_opaque_wrapper(struct whatever * ptr) {
// See 'Programming Ruby'
VALUE wrapper = Data_Wrap_Struct(c_MyData, 0, 0, ptr);
return wrapper;
}

// Wrapper function to access the normal C functions again
void access_do_something(VALUE wrapper) {
// Extract the C structure
struct whatever * ptr = 0;
Data_Get_Struct(wrapper, struct whatever, ptr);
// Call the C function
do_something(ptr);
return;
}

And so on. You'll want to read the links to Programming Ruby
given earlier.

This way your Ruby interface can be pretty much anything you
need. If you need to use values from those data structures *in*
Ruby (for manipulation or whatever), you can just write extraction
functions to be called at those times.

E

Execellent advice, sir. Thank you for your considerate answer.

George Wyche