saving pre-compiled scripts

[Derek van Vliet]

Hi,

I'm working on an application that reads python scripts from XML
elements and compiles them during my app's startup process using. The
application then runs the resulting compiled PyCodeObjects using
PyEval_EvalCode as they are needed.

Now I'm wondering if its possible to pre-compile the scripts and save
the PyCodeObjects in a binary file (or in CDATA in an XML element) and
have them ready to run when the application starts up.

My only constraint is that I need to be able to load the scripts from
memory (which is why using Py_CompileString has worked well for me).

Is there any way I can get the size of a PyCodeObject so that I could
save it to a binary file? If I did that would it run correctly if I
reloaded it and tried to Eval it? Can I load a pyc file from memory
somehow?

Any guidance would be greatly appreciated.

Thanks,
Derek

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Re: saving pre-compiled scripts

[Derek van Vliet]

Another thing which may be important to note re: my constraints is that
each script is essentially being run as a function.

In fact, every script element I parse in XML gets wrapped in a function
def before I send it to Py_CompileString.

I then PyEval the result of that function, and then run
Py_CompileString again, passing only the automatically generated
function call.

The result of the second Py_CompileString is what I pass to
PyEval_EvalCode whenever my app needs to run that script (function).

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Re: saving pre-compiled scripts

[Derek van Vliet]

I probably should have also mentioned that my application is written in
C++ and using the Python/C API.

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importing pyc from memory?

[Derek van Vliet]

Using the Python/C API, is there a way I can import a pyc file that I
have in memory (as opposed to loading from disk)?

I'm trying to save compiled python code in a proprietary file format to
cut reduce the overhead of compiling all my scripts when my app starts
up.

Derek

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Re: importing pyc from memory?

[Derek van Vliet]

Up to now, I've had all my python scripts defined in XML elements,
which were compiled when my program started up using Py_CompileString.
This has worked great, but I'm finding that most of the time my app
uses to start up is spent in that Py_CompileString, because of the
large number of scripts that I use.

Unfortunately, storing these scripts as .pyc files on disk is not an
option for me.

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Re: importing pyc from memory?

[Derek van Vliet]

The second method you describe sounds like it is along the lines of
what I need to do. Is there a way to do this using the Python/C API?

For instance, if I have the contents of a pyc file loaded entirely into
memory, and I have a pointer to the beginning of the file and the size
in bytes at my disposal, can I import that by any means?

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Re: importing pyc from memory?

[Derek van Vliet]

I do have to do everything you describe here in the current
implementation of my system. I realize that importing a pyc file and
compiling a string results in two different things. This is okay though
as I'm fairly sure this will still suit my needs.

As I said, the file format I plan to store these compiled scripts in is
proprietary, but it would be very comparable storing them in XML
elements as CDATA. I'm hoping that this would allow me to import and
run them, thereby removing the need for my app to compile scripts.

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