This paper will probably interest devotees of both denotational semantics and Prolog, but few others. The paper requires a fairly high level of sophistication in denotational semantics but only a moderate familiarity with Prolog.

The authors’ primary objective of “precisely defining a core Prolog semantics” seems to have been accomplished in principle. The effectiveness of the definition can be questioned, however, as it is not particularly perspicuous. The backtracking aspect of the Prolog search strategy seems to be the primary source of complexity in the definition. The authors state that continuations handle backtracking conveniently, but the seven continuation domains used in the definition and the resulting complicated semantic valuations do not make comprehension a straightforward matter.

In the latter part of the paper, the semantics of the metapredicate cut is given. Other metapredicates, such as assert and retract, evidently presented greater difficulties, and the authors indicate that they will be addressed in a subsequent paper.