anchor.diff:  // Character set.   Picks up the user specified character set, should it be present.
   //
   charSet
  -    : CHARSET_SYM WS+ STRING WS* SEMI
  +    : '@' CHARSET WS+ STRING WS* SEMI
       -> ^(CHARSET STRING)
       ;
   
   // ---------
   // Import.  Location of an external style sheet to include in the ruleset.
   //
  -cssImport
  -    : IMPORT_SYM WS+ cssImportLocation  (WS+ medium (WS* COMMA WS* medium)*)? WS* SEMI
  -    -> ^(IMPORT cssImportLocation medium*)
  -    ;
  -    
  -cssImportLocation : STRING|URI ;
  +importFile
  +    : IMPORT_SYM WS+ importLocation  (WS+ medium (WS* COMMA WS* medium)*)? WS* SEMI
  +    -> ^(IMPORT importLocation medium*)
  +    ;
  +    
  +importLocation : STRING|URI ;
   
   // ---------
   // Media.   Introduce a set of rules that are to be used if the consumer indicates
  
positive.code: IMPORT_SYM      : '@' I M P O R T       ;
  PAGE_SYM        : '@' P A G E           ;
  MEDIA_SYM       : '@' M E D I A         ;
  CHARSET_SYM     : '@charset'            ;
  
  
  IMPORTANT_SYM   : '!' (WS|COMMENT)* I M P O R T A N T   ;
  
negative.code: styleSheet  
      : WS*
        (charSet WS!*)?
        (importFile WS!*)*
        (bodyset WS!*)*
        EOF!
      ;
  