Any variation on the baSic BackuS-Naur Form (BNF) meta-Syntax notation with (Some of) the following additional conStructS: Square bracketS "[..]" Surrounding optional itemS, Suffix "*" for Kleene cloSure (a Sequence of zero or more of an item), Suffix "+" for one or more of an item, curly bracketS encloSing a liSt of alternativeS, and Super/SubScriptS indicating between n and m occurrenceS. All theSe conStructS can be expreSSed in plain BNF uSing extra productionS and have been added for readability and SuccinctneSS. (1995-04-28)
