This backward chaining goal is only relevant when writing a meta-interpreter for a context. It binds variable to the next preferred instantiation from the conflict set of the currently executing context.
This goal may be satisfied repeatedly each time returning the next instantiation. When no instantiations are left, it fails.
conflict-set
inst-bindings
inst-rulename
inst-token
start-cycle
fire-rule
defcontext
standard-context
KnowledgeWorks and Prolog User Guide (Unix version) - 6 Dec 2011