Any variation on the basiCBaCkus-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)