Object Function Dynamic Parameter Question

[Peter.Higgins]

Hello List,

I am considering a generic Object Key function that returns the padded value for any index of a file set in object instantiation without the overhead of using dictionary objects.  Thanks for the Key() tip Mike.   

There are examples of fully variable parameters here, but I could swear I've seen mixed versions that have the variable portion at the end.  I have been unable to find this in the forum or by searching the documentation. 
I guess the easy answer is directions to dynamic parameters in the documentation.

Assuming by value will work in a compiled iolist variable and the STATIC ckeyIolist$ is
ckeyIolist$=CPL("IOLIST (param1$), (param2$),(param3$),(param4$)")
this is how I think it probably could work. 

FUNCTION KeyFmt$(KeyNo,*)KEY_FMT ! Where * is the fields of the key.
!
KEY_FMT:
Pt$=STK(PROPERTIES);  IF NOT(MSK(pt$,"[Nn][Ss]+")) then EXIT 36
ENTER (KeyNo),iol=ckeyIolist$,err=*next
argCnt=LEN(Pt$)
! Format into key

[Peter.Higgins]

Testing has shown that this doesn't work.  Only the (*) is accepted by 2017.
I am experimenting with flexible Enter statements using arrays instead.