🚀 go-pugleaf

In article <6500005@uicsl> Mark Gooley (gooley@uicsl.UUCP) writes:
>
>Consider the following trivial predicate:
>
>a([]).
>a(_).
>
>Given the query :-a([]). , C-Prolog finds one match and UNSW Prolog finds two.
>Which is standard behavior?  How do other implementations behave?
>

Intuitively C-Prolog's  one  match is the  expected standard behaviour. The
two assertions describe a choice; it is either an empty  list or  something
else which differs from an empty list.
Aside: Also both Quintus Prolog and Mu-Prolog find one match.