<< obj { executable array } sendmsg >> When obj is in k-class (i.e. obj is of the form [<<class.Context>> , body ]), then the CurrentContextp is changed to <<class.Context>> and the obj <<executable array>> will be executed. If not, CurrentContextp is changed to the PrimitiveContextp and the obj <<executable array>> will be executed. cf. setcontext, newcontext, StandardContextp, system_variable, sendmsg2, primmsg, supmsg2.