anchor.diff:  // ---------
   // Body
   //
  -bodylist
  -	: bodyset*
  -	;
  -
  -bodyset
  +body
   	: ruleSet
   	| media
   	| page
  
positive.code: styleSheet
  	: charSet?
  	  imports*
  	  bodylist
  	  EOF
  		-> ^(N_StyleSheet charSet? imports* bodylist?)
  	;
  	
  // -----------------
  
negative.code: //
  media_query_list
  	: media_query (COMMA media_query)*
  		-> ^(N_MediaQuery media_query) +
  	;
  
  // We are not studying content of media query (as AND, NOT and ONLY tokens are not recognized)
  