anchor.diff:  
   // GRAMMAR OF A SUPERCLASS EXPRESSION
   
  -superclass_expression : superclass_method_expression | superclass_subscript_expression  superclass_initializer_expression  ;
  +superclass_expression
  +  : superclass_method_expression
  +  | superclass_subscript_expression
  +  | superclass_initializer_expression
  +  ;
  +
   superclass_method_expression : 'super' '.' identifier  ;
   superclass_subscript_expression : 'super' '[' expression ']'  ;
   superclass_initializer_expression : 'super' '.' 'init'  ;
  
positive.code: 
  expression_list : expression (',' expression)* ;
  
  expression
  	:	prefix_operator expression
      |	in_out_expression
  
negative.code: 
  // GRAMMAR OF A VARIABLE DECLARATION
  
  variable_declaration
   : variable_declaration_head pattern_initializer_list
   | variable_declaration_head variable_name type_annotation code_block
   | variable_declaration_head variable_name type_annotation getter_setter_block
   | variable_declaration_head variable_name type_annotation getter_setter_keyword_block
  