Understanding the declarative vs. operational semantics of Prolog (and how things like tabling can bridge the gap in some cases) is one of the most important co

Understanding the declarative vs. operational semantics of Prolog (and how things like tabling can bridge the gap in some cases) is one of the most important concepts to master. It's really a shame that that more Prologs don't support alternate operational models -- though it's pretty trivial to write meta-interpreters with your own semantics (such as breadth-first eval, etc.) it would be nice if there were canonical versions. For CLP & attributed-variables at least there is some universality.