anchor.diff:  // 9 General
   // 9.1 Attributes
   
  -attribute_instance : '(*' attr_spec ( ',' attr_spec )* '*)' ;
  +attribute_instance : '(' '*' attr_spec ( ',' attr_spec )* '*' ')' ;
   attr_spec : attr_name '=' constant_expression
   | attr_name
   ;
  
positive.code: // 9.4 Identifier branches
  
  simple_hierarchical_branch :
  Simple_identifier ( '[' Decimal_number ']' )? ( ( '.' Simple_identifier ( '[' Decimal_number ']' )? )* )?
  ;
  
  escaped_hierarchical_branch :
  Escaped_identifier ( '[' Decimal_number ']' )? ( ( '.' Escaped_identifier ( '[' Decimal_number ']' )? )* )?
  ;
  
  // 9.5 White space
  
negative.code:     :   hierarchical_function_identifier attribute_instance*
          '(' (expression ( ',' expression )*)? ')'
      ;
  system_function_call : system_function_identifier (expression ( ',' expression )*)? ;
  genvar_function_call : genvar_function_identifier attribute_instance*
                         '(' (constant_expression ( ',' constant_expression )*)? ')'
  ;
  