how to represent a self-described BNF in XML or RDF?

Hi,all

A self-described BNF as follows. how to represent it in XML or RDF?(i.e. how to represent a BNF in XML.)
syntax  ::=  { rule }
rule       ::=  identifier  "::="  expression
expression ::=  term { "|" term }
term       ::=  factor { factor }
factor     ::=  identifier |
                quoted_symbol |
                "("  expression  ")" |
                "["  expression  "]" |
                "{"  expression  "}"
identifier ::=  letter { letter | digit }
quoted_symbol ::= """ { any_character } """
Could anyone help me?

Regards,

lotus.W