Are Aggregates Fully Supported?

[damianoazzolini]

Hi. I'm writing a simple program but the following line:

fb(FB):- #count{ X : f(X), b(X)} = FB.

raises a syntax error (at FB after =).
However, by looking (very quickly) at the grammar in the source code, aggregates seems to be supported, but in limited form.
So, is there a way to represent the previously reported line within this tool?

Thanks.

[denismaua]

Hi Damiano,

Indeed aggregators are supported to some extent. For instance, the program

0.5::a(1).
b(1) :- #count{X: a(X)} = 1.
{a(2)}.
#query(b(1)).

parses just fine (and pasp outputs P(b(1)) in [0,1]). However, it seems that variables in the comparison operator are not supported, which seems to be your problem. So the program

0.5::a(1).

b(Y) :- #count{X: a(X)} = Y.
{a(2)}.

#query(b(1)).

will produce a parsing error at expression = Y. I believe a quick fix to the parser should solve the issue; I'll add it to our bug list.