[robmnl]

Appreciated, definitely clean code to express nodes and relationships.

Is there a modern implementation that's well supported by a community?

[giardini]

comp.lang.prolog is the prolog newsgroup. The comp.lang.prolog FAQ contains information about the various implementations: http://www.logic.at/prolog/faq/

SICSTUS Prolog ( http://www.sics.se/isl/sicstuswww/site/index.html ) is a widely used commercial implementation. There are others.

FOSS alternatives include:

- Ciao-Prolog, which might be noted for it's various extensions (breadth-first search, fuzzy logic, WWW programming interface, concurrency, persistence, and more) http://www.clip.dia.fi.upm.es/Software/Ciao/

- SWI-Prolog http://www.swi-prolog.org/