PyParsing contextual suggestions?

[Tim Chase]

I've just started tinkering around with PyParsing and have unable to
come up with an answer to the following without deep diving into the
code.  Is there a way to do a partial parsing and then get the list
of possible things that could appear at the terminus of the parsing?
 My hope is to implement context-aware suggestions in a
readline.py/cmd.py application.  So I might have a grammar that
knows about filenames, and could then appropriately suggest
file-names at the given point in a parsing of the command.

Any hints on where I should read up?

Thanks,

-tkc