On 05/17/2014 05:49 PM, Stefan Behnel wrote: > Roland Plüss, 17.05.2014 17:28: >> On 05/17/2014 04:01 PM, Stefan Behnel wrote: >>> Roland Plüss, 17.05.2014 15:49: >>>> On 05/17/2014 03:26 PM, Stefan Behnel wrote: >>>>> Roland Plüss, 17.05.2014 15:00: >>>>>> On 05/17/2014 01:58 PM, Stefan Behnel wrote: >>>>>>> Roland Plüss, 17.05.2014 02:27: >>>>>>>> I'm using Python in an embedded situation. In particular I have to load >>>>>>>> python scripts through a memory interface so regular python module >>>>>>>> loading can not be used. I got working so far a module loader object >>>>>>>> I've added using C++ to sys.meta_path . Now I'm totally stuck at the >>>>>>>> finally loading step. >>>>>>>> >>>>>>>> I've got this a C++ loader method "load_module(fullname)" which does >>>>>>>> load the requested module script files into a null-terminated string. I >>>>>>>> know that "load_module" has to return the module PyObject*. But I can't >>>>>>>> get the python source in the c-string into a module PyObject*. >>>>>>>> [...] >>>>>>>> Can anybody help how in gods name one is supposed to create a module >>>>>>>> from an in-memory c-string when called from within load_module (or >>>>>>>> anywhere)? >>>>>>> Looks like you want to implement a SourceLoader: >>>>>>> >>>>>>> https://docs.python.org/3.4/library/importlib.html#importlib.abc.SourceLoader >>>>>>> >>>>>>> I recommend implementing this in Python code instead of C code, though. >>>>>>> Much easier. Cython can help with the integration between both. >>>>>> That doesn't work in 2.x, doesn't it? >>>>> Is there a reason you have to use Py2? >>>>> >>>>> Anyway, PEP 302 predates Py3 by a couple of years: >>>>> >>>>> http://legacy.python.org/dev/peps/pep-0302/ >>>> I'm willing to go to Py3 but only if the solution to the problem is >>>> simpler than getting it fixed in Py2. So some questions first: >>>> >>>> - does this importlib stuff you showed there apply to C++ land (I need >>>> to fully drive it from C++ not Python code)? >>> As I said, implementing this in Python code is much simpler than doing it >>> in C/C++ code. Basically, stop where you got the C string and do the rest >>> in Python. All your C code has to do is to take a module lookup request >>> from your custom Python module Finder and return a byte string with the >>> code. Then let your Python code wrap that in a Loader and return it to the >>> import machinery. >> I don't get how this is supposed to work. I'm running it as fully >> embedded Python. There is no main script. The builtin modules are added >> as C++ bound classes and a user made main script is loaded but not run >> directly (I'm hooking into a create object). For this purpose I load the >> script module using C++ code using PyImport_ImportModule(moduleName). At >> this time the module loading code has to kick in already (I've added >> this one by C++ too before). The problem is now that in this call I end >> up in my C++ loader version where there is no Python script involved. I >> came to the conclusion that I can solve this only by having the C++ end >> properly load the module. I could add Python code with >> PyRun_SimpleString but then I'm down to the same problem as before: how >> to evaluate code so it is attached to a module or type-class? As I >> understand it the problem is the same as before just pushed around a bit. > No, just run some Python code (using PyRun_SimpleString() if you have to) > and let it do whatever you like. Such as, defining a Finder class and > injecting it into the import hook. Just provide it with the entry point of > your C++ loader as a (CFunction) object when you execute it, and then let > it call that function at need whenever the Finder gets executed. > > Alternatively, compile your Python integration code with Cython and link it > into your main program as yet another binary extension module. > > Stefan > > I'm not using Cython so that's out of question. Concerning the injection how would this work? From the PEP I assume it would have to look like this:
# CODE #
import sys
class VFSModuleLoader:
def find_module(fullname, path=None):
return self if VFS.exists( vfsPathFromFullname(fullname) ) else None
def load_module(fullname):
sourceCode = VFS.read( vfsPathFromFullname(fullname))
???
# CODE #
How does ??? work? If I use "eval" I end up with the code inside
VFSModuleLoader.load_modules as context but it should go into the global
context as an own module.
--
Yours sincerely
Plüss Roland
Leader and Head Programmer
- Game: Epsylon ( http://www.indiedb.com/games/epsylon )
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, http://dragengine.rptd.ch/wiki )
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- As well as various Blender export scripts und game tools
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