A two argument lambda list.
A function body.
Defines a new conflict resolution tactic named tactic-name. The type of the tactic may be
:static if the body does not look into the slots of the objects making up the instantiation, otherwise
:dynamic. The lambda-list binds to two instantiation objects and the function body body should return non-nil if and only if the first instantiation object is preferred to the second.
deftactic also defines a function of the same and body can be preceded by a documentation string.
(defcontext my-context :strategy (prefer-trucks))
KnowledgeWorks and Prolog User Guide (Macintosh version) - 24 Mar 2017