anchor.diff:     ;
   
   name_of_gate_instance
  -   : gate_instance_identifier (range)?
  +   : gate_instance_identifier (range_)?
      ;
   
   // 3.2 Primitive strengths
  
positive.code:    ;
  
  name_of_instance
     : module_instance_identifier (range)?
     ;
  
  list_of_port_connections
  
negative.code:    : '[' dimension_constant_expression ':' dimension_constant_expression ']'
     ;
  
  range_
     : '[' msb_constant_expression ':' lsb_constant_expression ']'
     ;
  
  