Second argument indexing?

Does SWI-Prolog index on 2nd arguments? The section on JITI mentions “first argument” a number of times. jiti_list/0 doesn’t seem to list the special case of [] and [_|_] (e.g., apply:maplist_/3).

(From a quick look at the VM instructions generated by apply:maplist_/3 and a naive version that leaves the Goal as the first argument, I’m guessing that there is 2nd argument indexing.)

non-first argument indexes only use hash indexes. Only on the first argument there are the dedicated [] vs [_|_] and quick linear scan for a small number of clauses. Of course, all this can be changed …

Do the hash indexes show with jiti_list? Or are they implicit in the VM instructions?

Jiti list should show them.