Language plugins : Implementation

The function parse_top_item must be provided. Usually you can just copy this.

/*--------------------------------------------------------------------------*/
void LANG_VERILOG::parse_top_item(CS& cmd, CARD_LIST* Scope)
{
  cmd.get_line("gnucap-verilog>");
  new__instance(cmd, NULL, Scope);
}
/*--------------------------------------------------------------------------*/

It parses one line of input, where the definition of “line” may differ depending on the language.

The string, in this case “gnucap-verilog>” is used as a prompt in interactive mode, and is suppressed when reading from a file.

For educational purposes, the code for new__instance follows. You do not need to duplicate it.

You do need to provide find_type_in_string, which returns the type as a string, by scanning the input.

parse_item is shown here. It dispatches to one of parse_module, parse_instance, parse_paramset, parse_comment, or parse_command, which you must provide.

/*--------------------------------------------------------------------------*/
void LANGUAGE::new__instance(CS& cmd, MODEL_SUBCKT* owner, CARD_LIST* Scope)
{
  if (cmd.is_end()) {
    // nothing
  }else{
    std::string type = find_type_in_string(cmd);
    if (const CARD* proto = find_proto(type, owner)) {
      CARD* new_instance = proto->clone_instance();
      assert(new_instance);
      new_instance->set_owner(owner);
      CARD* x = parse_item(cmd, new_instance);
      if (x) {
	assert(Scope);
	Scope->push_back(x);
      }else{
      }
    }else{
      cmd.warn(bDANGER, type + ": no match");
    }
  }
}
/*--------------------------------------------------------------------------*/
CARD* LANGUAGE::parse_item(CS& cmd, CARD* c)
{
  // See Stroustrup 15.4.5
  // If you can think of a better way, tell me.
  // It must be in the LANGUAGE class, not CARD.
 
  if (dynamic_cast<MODEL_SUBCKT*>(c)) {
    return parse_module(cmd, prechecked_cast<MODEL_SUBCKT*>(c));
  }else if (dynamic_cast<COMPONENT*>(c)) {
    return parse_instance(cmd, prechecked_cast<COMPONENT*>(c));
  }else if (dynamic_cast<MODEL_CARD*>(c)) {
    return parse_paramset(cmd, prechecked_cast<MODEL_CARD*>(c));
  }else if (dynamic_cast< DEV_COMMENT*>(c)) {
    return parse_comment(cmd, prechecked_cast<DEV_COMMENT*>(c));
  }else if (dynamic_cast<DEV_DOT*>(c)) {
    return parse_command(cmd, prechecked_cast<DEV_DOT*>(c));
  }else{untested();
    incomplete();
    unreachable();
    return NULL;
  }
}
/*--------------------------------------------------------------------------*/