event ok.
event ko.

query event(ko).
query event(ok).

process
	if 1 = 2 + (3 - 4) then event ok else event ko

(* EXPECTPV
RESULT not event(ko) is true.
RESULT not event(ok) is true.
0.008s (user 0.004s + system 0.004s), max rss 7504K
END *)
