caller() 
{
	cscp_cmd cmd;
	cscp_state state = CSCP_STATE_AUTH;
	while(1) {
		cmd = read_cmd(state);
		if (cmd == EOF_CMD) {
			break;
		}
		if (!cmd_valid(cmd, state)) {
			return EBADCMDFORSTATE;
		}
		process(cmd);
	}
}

read_cmd(cscp_state state) 
{
	int cmd, token;
	list_t list;
	cscp_cmd *ret;

	cmd = yylex(); /* lex changes to token state */
	while ((token = yylex()) != TOK_EOL) {
		add_to_list(list, item, yytext);
	}

	ret = build_cmds[cmd](list);
	if (!ret) {
		ERROR;
	}
	return ret;
}

build_<cmd_specific>_cmd(list_t list)
{
	cscp_cmd *cmd = malloc(...);

	for each item in list {
		if (item_gmakes_sense(item)) {
			process_item(item, cmd);
		} else {
			free(cmd);
			return NULL;
		}
	}
	return cmd;
}