The following figure shows a sample of a complex syntax description. This is not an example of an exis- ting system parameter or panel command. It is used mainly to demonstrate the “look and feel” of syntax descriptions.
CMDNAME required argument [optional argument] {required choice 1 | required choice 2 | required choice 3} [optional choice 1 | optional choice 2] REQUIRED KEYWORD=variable [OPTIONAL KEYWORD=variable] [DEFAULT KEYWORD | KEYWORD 1 | KEYWORD 2] [KEYWORD=default choice | KEYWORD={choice 1 | choice 2}] repeatable item n {repeatable item n ...} repeatable item n {,repeatable item n ,...} fragment name (variable 1, variable 2) fragment_name [DEFAULT KEYWORD | KEYWORD 1 | KEYWORD 2 | KEYWORD 3 | KEYWORD 4] KEYWORD={choice 1 | choice 2 | choice 3 | choice 4}
All syntax is described using the Extended Backus-Naur form wherever possible. This article is intended to help content creators understand the formatting and to make them understandable by the readers.
<ebnf> "EBNF defined in itself" { syntax = [ title ] "{" { production } "}" [ comment ]. production = identifier "=" expression ( "." | ";" ) . expression = term { "|" term } . term = factor { factor } . factor = identifier | literal | "[" expression "]" | "(" expression ")" | "{" expression "}" . identifier = character { character } . title = literal . comment = literal . literal = "'" character { character } "'" | '"' character { character } '"' . }</ebnf>