[C++-sig] Executing python code from C++
seefeld at sympatico.ca
Sun Feb 7 15:51:42 CET 2010
On 02/07/2010 08:29 AM, Murray Cumming wrote:
> So, I guess I can use boost::python::exec() to call code that defines a
> Python function.
bpl::exec() executes a chunk of Python code, no matter what it contains.
> But how can I get a boost::python::object for the (callable object of)
> the function? In C, I'm using PyDict_GetItemString() for that.
Sorry, I don't understand the question. Can you give an example of what
you want to do ? May be you want to "exec" some python code that defines
a function, which you then want to extract and call later ?
That may look like this:
// Retrieve the main module
bpl::object main = bpl::import("__main__");
// Retrieve the main module's namespace
// Define the 'embedded' Python code...
std::string py_code = "def greeting(): print 'hello world !'";
// ...and execute it.
bpl::object result = bpl::exec(py_code, global, global);
// Extract the function
bpl::object greeting = global["greeting"];
// Call it
You may combine this with the other techniques outlines previously. For
example, your Python code may define types based on previously exported
C++ types (Python classes derived from C++ classes, say), and then
extract them to gain back C++ references to base classes. There are
endless possibilities to play with such hybrid code... :-)
...ich hab' noch einen Koffer in Berlin...
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