The delayed answers may indicate that it is hard to see what you really intent.
Of course there is no special id field present for all data types in Nim -- for
a plain int with bytesize 4 or 8 that field would double storage consumption
and decrease computing performance. For real objects we may have used an id
field, but why should one. And for your custom objects you can add whatever
field you desire.
Note that in computers nearly all instances of data types have addresses in
memory, so you may use them for your is:
proc main =
var a: int
var b: ref int = new int
echo cast[int](a.addr)
echo cast[int](b.addr)
main()
Run
