addendum:
Some times ago, I played a bit with a cool Prolog implementation in Squeak
IIRC, it had some features you are looking for: IDE integration,
compiler, runtime and semantics.
I'm not sure it is this one, it was several years ago, but googling a
bit I found
http://map.squeak.org/package/cb6c7afe-d517-470f-8857-d764ef321725
http://www.zogotounga.net/comp/squeak/prolog.htm
owner MarkusDenker, ... mmm I think I've already seen that name ? ... ;)
may be worth have a look too.
And of course there is Newspeak (way cool too), I think Eliot is
maintaining the vm (?) and may be you could have some support from him?
Regards,
Alain
