Packing a simple dictionary into a string - extending struct?

[Jonathan Fine]

Hello

I want to serialise a dictionary, whose keys and values are ordinary strings
(i.e. a sequence of bytes).

I can of course use pickle, but it has two big faults for me.
1.  It should not be used with untrusted data.
2.  I want non-Python programs to be able to read and write these
dictionaries.

I don't want to use XML because:
1.  It is verbose.
2.  It forces other applications to load an XML parser.

I've written, in about 80 lines, Python code that will pack and unpack (to
use the language of the struct module) such a dictionary.  And then I
thought I might be reinventing the wheel.  But so far I've not found
anything much like this out there.  (The closest is work related to 'binary
XML' - http://en.wikipedia.org/wiki/Binary_XML.)

So, what I'm looking for is something like and extension of struct that
allows dictionaries to be stored.  Does anyone know of any related work?

-- 
Jonathan Fine