WTX does not support the use of a variable in an array. So this request is to add this feature in future WTX/ITX releases.
That is, a variable can not be used in an indexed field.
For example, you can not use Name[INDEX($)] or Name[x], where x being a variable.
Only a defined numeric value is allowed for referring the ranged fields i.e Name, Name.
This feature will be beneficial for the whole WTX community as this would save a lot of time and efforts for the developers.