anchor.diff:  
   Block_comment : '/*' (Block_comment|.)*? '*/' -> channel(HIDDEN) ; // nesting allow
   
  -Line_comment : '//' .*? '\n' -> channel(HIDDEN) ;+Line_comment : '//' .*? '\n' -> channel(HIDDEN) ;
  
positive.code:  | type_name generic_argument_clause? '.' type_identifier
   ;
  
  type_name : identifier  ;
  
  // GRAMMAR OF A TUPLE TYPE
  
  
negative.code: 
  function_declaration : function_head function_name generic_parameter_clause? function_signature function_body  ;
  function_head : attributes? declaration_specifiers? 'func'  ;
  function_name : identifier |  operator  ;
  function_signature : parameter_clauses function_result? ;
  function_result : '->' attributes? type  ;
  function_body : code_block  ;
  