captures and returns the current continuation as an escape procedure. Typically used as follows
(let ((cc (escape-procedure))) (cond ((escape-procedure? cc) ;; normal body ;; possibly calling (cc val) ... ((ok? cc) ;; exceptional case ;; do something with cc ...))
Note, that the let is invoked twice, first after the call to escape-procedure, then with the object val, which was bound to cc by calling (cc val).