This paper describes a Lisp-based multi-paradigm programming language TAO that incorporates a logic programming (LP) paredigm. Whereas previous multi-paradigm languages only supported purely functional and LP facilities, TAO supports all Lisp primitives as well as LP facilities. This amalgamation of Lisp and LP is done by making use of the similarities in their execution mechanisms, giving a natural semantics to the amalgamation. The similarities include state vs. logic variables, function vs. predicate calling, and non-local exit vs. back- tracking. For example, the similarity between non-local exit (catch/throw) and backtracking enables backtracking to be regarded as a kind of non-local exit, so that backtracking can use all Lisp facilities which support non-local exit.
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