anchor.diff:     | '||'
      ;
   
  +LCURL
  +   : '{'
  +   ;
  +
  +RCURL
  +   : '}'
  +   ;
  +
   LPAREN
      : '('
      ;
  
positive.code:    | expression OPERATOR expression
     | LPAREN expression RPAREN
     | expression '?' expression ':' expression
     ;
  
  RESOURCEREFERENCE
     : [a-zA-Z] [a-zA-Z0-9_-]* RESOURCEINDEX? '.' ([a-zA-Z0-9_.-] RESOURCEINDEX?)+ 
     ;
  
  RESOURCEINDEX
  
negative.code:    ;
  
  map
     : '{' argument* (',' argument)* '}'
     ;
  
  string
  