In addition to this standard definition of EBNF, the following notational conventions are used.
The counting repetition: Anything enclosed by { and } and followed by a superscripted expression x must appear exactly x times. x may also be a non-terminal. In the following example, exactly four stars are allowed:
Stars = {*}4.
The size in bytes: Any identifier immediately followed by a number n in square brackets ([ and ]) may be assumed to be a binary number with the most significant byte stored first, having exactly n bytes. The following listing shows the example.
Struct = RefNo FilePos[4].
In some examples, text is enclosed by < and >. This text is a meta-literal, that is, whatever the text says may be inserted in place of the text (confer <any char> in the above listing, where any character can be inserted).