Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. In programming languages, a composable continuation, delimited continuation or partial continuation, is a "slice" of a continuation frame that has been reified into a function. Unlike regular continuations, delimited continuations return a value, and thus may be reused and composed. Various operators for delimited continuations have been proposed in the research literature. One proposal offers two operators, shift and reset, to work with such continuations. reset sets the limit for the continuation. shift captures the current continuation up to the innermost enclosing reset limit, takes a function argument and passes the captured continuation to it. If the delimited continuation is invoked with parameter p, the computation is suspended and p is returned by shift. However, if the delimited continuation is not invoked, but the function passed to shift returns normally, then its value becomes the return value of reset. When the entire computation within reset is completed, the result is returned by the delimited continuation.