anchor.diff:  // 9.4 Identifier branches
   
   simple_hierarchical_branch :
  -Simple_identifier ( '[' Decimal_number ']' )? ( ( '.' Simple_identifier ( '[' Decimal_number ']' )? )* )?
  +	Simple_identifier ( '[' Decimal_number ']' )?
  + 	( '.' Simple_identifier ( '[' Decimal_number ']' )? )*
   ;
   
   escaped_hierarchical_branch :
  -Escaped_identifier ( '[' Decimal_number ']' )? ( ( '.' Escaped_identifier ( '[' Decimal_number ']' )? )* )?
  +	Escaped_identifier ( '[' Decimal_number ']' )?
  +	( '.' Escaped_identifier ( '[' Decimal_number ']' )? )*
   ;
   
   // 9.5 White space
  
positive.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 )*)? ')'
  ;
  
negative.code: default_clause : 'default' ;
  inst_clause : 'instance' inst_name ;
  inst_name : topmodule_identifier ( '.' instance_identifier )* ;
  liblist_clause : 'liblist' library_identifier* ;
  cell_clause : 'cell' ( library_identifier '.' )? cell_identifier ;
  use_clause : 'use' ( library_identifier '.' )? cell_identifier ( ':config' )? ;
  
  