Does ECLiPSe run standard Prolog code?
Yes, ECLiPSe is largely compatible with standard Prolog, and in addition, has libraries which provide almost full compliance with ISO Prolog and other Prolog dialects, such as SICStus Prolog, on a per-module basis. ECLiPSe implements some extensions (primarily to support constraints and program-in-the-large, but also others too), which are documented in chapter 5 of the User Manual.