SymbolicName

EBNF

SymbolicName = UnescapedSymbolicName
             | EscapedSymbolicName
             | HexLetter
             | (C,O,U,N,T)
             | (F,I,L,T,E,R)
             | (E,X,T,R,A,C,T)
             | (A,N,Y)
             | (N,O,N,E)
             | (S,I,N,G,L,E)
             ;

UnescapedSymbolicName = IdentifierStart, { IdentifierPart } ;

(* Based on the unicode identifier and pattern syntax
 *   (http://www.unicode.org/reports/tr31/)
 * And extended with a few characters.
 *)IdentifierStart = ID_Start
                | Pc
                ;

(* Based on the unicode identifier and pattern syntax
 *   (http://www.unicode.org/reports/tr31/)
 * And extended with a few characters.
 *)IdentifierPart = ID_Continue
               | Sc
               ;

(* Any character except "`", enclosed within `backticks`. Backticks are escaped with double backticks.
 *)EscapedSymbolicName = { '`', { ANY - ('`') }, '`' }- ;

Referenced from