The USE command is used to invoke a Built-In Function (BIF). Arguments may be passed to the Built-In Function and values may be returned by the Built-In Function.
Required
USE ---------- BUILTIN ------ built in function name ------>
-----------------------------------------------------------------
Optional
>-- WITH_ARGS ---- list of arguments ----------->
| expandable group expression |
--------- 20 maximum --------
>-- TO_GET ------- list of field names ---------|
| expandable group expression |
-------- 20 maximum ---------