A built-in backward chaining goal which implements a meta-interpreter for the default (normal) behavior of a context. It is as if defined by the rule
(defrule standard-context :backward
((standard-context)
<--
(start-cycle)
(instantiation ?instantiation)
(fire-rule ?instantiation)
(cut)
(standard-context)))
(defcontext my-context1
:meta (((format t "~%Entering context MY-CONTEXT1"))
(standard-context)))
KnowledgeWorks and Prolog User Guide (Unix version) - 26 Feb 2015