arg-type = hierarchy;
arg-type = nested;
This denotes an option with a structure-valued argument, a.k.a.
subopts in getopts terminology. The argument is parsed
and the values made available to the program via the find and
find next calls (See optionFindValue,
See optionGetValue, and
see optionFindNextValue).
tOptionValue * val = optionGetValue(VALUE_OPT_OPTN_NAME, "name");
while (val != NULL) {
process(val);
val = optionNextValue(VALUE_OPT_OPTN_NAME, val);
if (wrong_name(val, "name"))
break;
}