From grammar based file to xml file

Hi,

I have a bunch of program config files with sentences based on a 
grammar. The files and the grammar were written to be used with the yacc 
parser. Now I have to port the code from c to python, so I'd like to 
rewrite these config files as xml to parse them with xml python standard 
tools.

The usual approach to do that is write a parser that map a sentence to a 
xml element using DOM to generate the XML output.

I wonder if there is a generic parser out there capable of, given a 
grammar and a file based on this grammar, generate the xml equivalent of 
the file for whatever file and grammar. I think it is theoretically 
possible.

Somebody knows from such generic parser?

Thanks in advance

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Conchi Labra