Parsing csh scripts with python

[David Hirschfield]

Is there a module out there that would be able to parse a csh script and 
give me back a parse tree?

I need to be able to parse the script, modify some variable settings and 
then write the script back out so that the only changes are the 
variables I've modified (comments, ordering of statements, etc. must 
remain the same).

I looked at shlex, but I don't think it will do what I need.
Any suggestions would be appreciated,
-Dave

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