Hi,
There is a problem in the current $CRYSTAL/plugins/cscript/cspython, in that
the csPython::Call functions have no implementation. Naturally I want to fill
out these functions, but it would make and break the current iScript object.
Not to be bullish, but
bool csPython::LoadModule(const char* name)
{
csString s;
s << "import " << name;
return RunText(s);
}
is bad, since the only way I can explicitly load python files
(i.e ./data/custom.py), is to modify PYTHONPATH (which CS doesn't have a
function for as far as I'm aware and is platform dependent), then import that
module.
Take this code (minus the error checking and INC/DECREF's for clarity)
-- amir.py --
def foo(a, b):
return a * b
-- main.cpp --
#include <iostream>
#include <Python.h>
int main()
{
Py_Initialize();
/*PyObject* pyIntObject = PyInt_FromLong(5);
if (pyIntObject == NULL) ; // Error
Py_DECREF(pyIntObject);
PyRun_SimpleString("print 'hello'");*/
// open file and load module
FILE *file = fopen("amir.py", "r");
PyRun_SimpleFile(file, "amir.py");
// get main module
PyObject *main_module = PyImport_AddModule("__main__");
PyObject *global_dict = PyModule_GetDict(main_module);
// get function from global namespace
/*! this bit I'm unsure of... can I load the function, explicitly
from the loaded file? I remember being able to do so, but can't
find out how... */
PyObject *foo = PyDict_GetItemString(global_dict, "foo");;
PyObject *arg1 = PyInt_FromLong(2), *arg2 = PyInt_FromLong(8);
// make tuple of arguments
PyObject *args = PyTuple_New(2);
PyTuple_SetItem(args, 0, arg1);
PyTuple_SetItem(args, 1, arg2);
// call function and get return object
PyObject *ret = PyObject_CallObject(foo, args);
int result = PyInt_AsLong(ret);
std::cout << result << "!\n";
Py_Finalize();
return 0;
}
There are 2 changes that would be made here
1) csPython::LoadModule(..) would load absolute paths as opposed to pythonic
module style
is->LoadModule("x.k") becomes is->LoadModule("../some/path/maybe/vfs/x/k.py")
2) the csPython::Call functions get implemented.
I've already modified cspython and the pysimp to get a working prototype
int result = 0;
is->Call("foo", result, "");
printf("result : [%i]\n",result);
The problem here is that functions exist in the global namespace :S, each
function must have a unique identifier.
Here is another alternative which I haven't yet tried. (better from a python
POV, but maybe not the best for CS)
#include <Python.h>
int main()
{
char *cstrret;
Py_Initialize();
PyObject *module = PyImport_ImportModule("amir");
PyObject *foo = PyObject_GetAttrString(mymod, "foo");
PyObject *args = ...; // build value or whatever
PyObject *ret = PyEval_CallObject(foo, args);
Py_Finalize();
return 0;
}
This is a different approach, which I would prefer where it not for the
structural changes it would bring to iScript. For a start the module
references would have to be stored somehow (hash map or iScriptModule?), and
then the functions called by doing
iscript->FindLoadedModule("amir")->Call("foo", &i, 2, 8);
Preferrably if it is possible to mix first one (so can load python files from
VFS paths) and second one (being explicit about which function the module is
called from)- it should be, but I can't remember/find out how.
What do you all think?
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