Extended BNF Notation
EBNF consists of terminal symbols (literals) and non-terminal production rules (variables).
Here is an example:
Here are what its notations mean:
:=
- is defined a
"..."
- terminal string (aka terminal symbol)
- that is, a string literal (as opposed to a variable)
- obversely, non-terminal strings are variables to be replaced with terminal string
*
- repetition symbol
(...)
- grouping
;
- terminator symbol
References
https://en.wikipedia.org/wiki/ExtendedBackus%E2%80%93NaurForm