VAR_USERNAME
{ YDVAR(1, VAR_USERNAME) }
server_username: VAR_USERNAME STRING_ARG
%token VAR_CHROOT VAR_USERNAME VAR_DIRECTORY VAR_LOGFILE VAR_PIDFILE
| VAR_USERNAME STRING
%token VAR_USERNAME
server_username: VAR_USERNAME STRING_ARG
%token VAR_CHROOT VAR_USERNAME VAR_DIRECTORY VAR_LOGFILE VAR_PIDFILE