[PD] outputting arbitrary size list

[Jonathan Wilkes via Pd-list]

Hi list,
      I'm looking for an example interface that I cannot find atm-- how 
to accumulate an arbitrary-length list and output it from a Pd object 
written in C.  I can think of several ways to do it but if there's 
already something that exists I'd rather just hook into that.

I want to add a few messages to [canvasinfo] to return a list of 
matching object indices on the canvas.  So I need to be able to iterate 
through all the objects in the canvas, add them to a list if they match, 
then output that list.

Any externals out there that would contain a decent model for doing 
this?  I looked at the code for [list append] but that only glues 
together two lists, where I may be adding a large number of float atoms 
for a single output.

Thanks,
Jonathan