EBNF (see Appendix 1: Extended Backus-Naur Form) is used to describe blade design data so that a succinct structure view can be achieved.

Non-terminals can be mapped to XML elements by following the general rule:

<Element>::=Something becomes <Element>Something</Element>

Terminals can be mapped to XML content.

With these two mapping rules, NDF data following BNF can be read from, or written to, XML files.

The BNF rules used by the turbomachine NDF are listed in Appendix 2: BNF Rule List.