+ (cons (cons 'the 'man)
+ (cons 'read
+ (cons 'the
+ (cons (damn)
+ 'book))))
+
+where `(damn)` doesn't have widest scope. And we don't want to have to recruit all the other semantic material into accepting and passing along a possible expressive argument.
+
+How to do this?
+
+It's not immediately clear how to do it with "undelimited" continuations, of the sort captured by `call/cc`. This is the natural first thing to try:
+
+
+ (define damn (lambda () (call/cc (lambda (k) (cons (cons 'side-effect 'bad) (k 'id))))))
+
+
+The idea here is we capture the continuation that the thunk `(damn)` has when it gets evaluated. This continuation is bound to the variable `k`. We supply `'id` as an argument to that continuation. When the main-issues tree is all built, then we return a pair `((side-effect bad) MAIN-ISSUE-TREE)`.
+
+However, this doesn't work. The reason is that an undelimited continuation represents the future of the evaluation of `(damn)` *until the end of the computation*. So when `'id` is supplied to `k`, we go back to building the main-issue tree until we're finished *and that's the end of the computation*. We never get to go back and evaluate the context `(cons (cons 'side-effect 'bad) ...)`.
+
+The straightforward way to fix this is to use, not undelimited continuations, but instead a more powerful apparatus called "delimited continuations." These too will be explained in due course, don't expect to understand all this now.
+
+A delimited continuation is captured not by using `call/cc`, but instead by using a variety of other operators. We'll use the operator `shift`. This substitutes for `call/cc`. The syntax in Scheme is slightly different. Whereas we wrote:
+
+ (call/cc (lambda k ...))
+
+we instead write:
+
+ (shift k ...)
+
+but the behavior is the same. It's just that now our continuation doesn't stretch until the end of the computation, but only up to some specified limit. The limit of the continuation is specified using the syntax:
+
+ (reset ...)
+
+This is a kind of continuation-scope-marker. There are some interesting default behaviors if you don't explicitly specify where the limits are. But we'll be fully explicit here.
+
+If a block `...` never invokes a shift, then `(reset ...)` will evaluate just the same as `...`. So for uniformity, we can designate our continuation-scopes even on computations that don't capture and manipulate continuations.
+
+Going back to the beginning, then. We start with:
+
+ (define damn (lambda () 'id))
+
+We evaluate:
+
+ (reset (cons (cons 'the 'man)
+ (cons 'read
+ (cons 'the
+ (cons (damn)
+ 'book)))))
+
+Remember, the reset isn't actually *doing* anything. It's not a function that's taking the other material as an argument. It's instead a scope-marker. Here it's not even needed (and in fact in the interactive interpreter, it wouldn't even be needed when we invoke continuations, because of the default position it takes). But we're inserting it to be explicit and uniform.
+
+Evaluating that gives us:
+
+ ((the . man) . (read . (the . (id . book))))
+
+
+Now to pair that with an expressive side-issue content, we'd instead define `damn` as:
+
+ (require racket/control) ; this tells Scheme to let us use shift and reset
+ (define damn (lambda () (shift k (cons (cons 'side-effect 'bad) (k 'id)))))