Re: [Discuss-gnuradio] Python function processing block

[Johnathan Corgan]

Marcus Leech wrote:

> There was discussion on the list a few months ago about adding the
> ability to hook a python function
>  into the processing chain.   I don't remember what the conclusion of
> that discussion was.
> 
> I have a need to be able to hook a user-defined Python code snippet into
> the processing chain, near the end
>  where the sample rate is very low (1Hz).   Is this easily done, and if
> so, how?

Take a look at gr.feval_xx class:

http://gnuradio.org/trac/browser/gnuradio/trunk/gnuradio-core/src/lib/general/gr_feval.h

It defines a function 'eval' that can be called either from C++ or from
Python.  In Python you can subclass this and override the eval function
with whatever you want.  When the function is called from C++, control
flow passes to the Python interpreter to evaluate the function and return.

I haven't used it myself, but you can get a good feel for what is
possible by looking at the QA code for the block at:

http://gnuradio.org/trac/browser/gnuradio/trunk/gnuradio-core/src/python/gnuradio/gr/qa_feval.py

Johnathan Corgan, AE6HO
address@hidden