need entry widget to dynamically resize to fit contents

[george young <gry ll mit edu>]

[gtk-2.2.0, pango-1.2.0, pygtk-1.99.14, python-2.3a1, linux]
I need a gtk2 entry widget to expand (and hopefully contract too)
so as to always display just the text it contains.  It is critical
that all the text be visible, not scroll out of sight.  I'm using a
monospace font.  Is there some neat way to do this?  

I've tried a 'changed' callback which does set_size_request, but
calculating the right value (in a multiplatform environment) seems 
very hard.  Am I missing something simple?

-- George

-- 
 I cannot think why the whole bed of the ocean is
 not one solid mass of oysters, so prolific they seem. Ah,
 I am wandering! Strange how the brain controls the brain!
	-- Sherlock Holmes in "The Dying Detective"