document parser in BNF

Hi list,

I am trying to document a parser using BNF format. What I am trying to
achieve is something like this:

https://docs.python.org/3.4/reference/compound_stmts.html

In other words I would like to add boxes with a three column table

<expr>  | ::= | <expr1>
<expr1> | ::= | <expr2>

and would like to be able to link <expr*> on the right hand side to
corresponding <expr*> on the left hand side. I haven't found a good
solution though. Doxygen doesn't seem to support header-less tables,
nor custom anchors other than bare html anchors.

Any suggestions would be greatly appreciated.

Thanks,

Nick

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