This is related to the so-called "resumption model" of exception handling, in which some exceptions are said to be "continuable": it is permitted to return to the expression that signaled an exception, after having taken corrective action in the handler. The condition system is generalized thus: within the handler of a non-serious condition (a.k.a. "continuable exception"), it is possible to jump to predefined restart points (a.k.a. "restarts") that lie between the signaling expression and the condition handler. Restarts are functions closed over some lexical environment, allowing the programmer to repair this environment before exiting the condition handler completely or unwinding the stack even partially.