[Discuss-gnuradio] Grabbing object references in GRC

[Marcus D. Leech]

One of the things I've wanted to do for some time is the ability to pass 
a reference to a flow-graph object to "helper" Python code that I often 
import
  into my flow-graphs.  Such "helper" code is often called upon to do 
things like calculate filter coefficients, or other variable settings 
where the setting
  equation/algorithm is a little too cumbersome to be expressed insde a 
parameter field directly.  I also use such "helper" code to do things like
  logging low-rate data from a function_probe.

The function probe stuff, internally, basically aquires a reference to 
the target block in the flow-graph, and calls an arbitrary method off that
  object, at some programmable rate.

I'd like to be able to make that more general, so that I could pass such 
an object reference to my "helper" functions without having to edit
  the generated Python.

I *think* it should be fairly straightforward to define a new type of 
variable that simply holds a reference to an object, and which can be passed
  around like other variables in GRC, and in particular passed into one 
of my "helper" functions.

The particular use-case I have in front of me now is the ability to set 
gpio pins, which is currently not really possible from GRC flow-graphs, 
since
  you have to acquire a dboard_iface object first, which in turn means 
you need a handle to the containing multi_usrp object.

Discuss :)


--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org