check

book.tex

@@ -8897,12 +8897,12 @@ the control-flow graph with another auxiliary function named
 \code{add-node}. That function returns the label for the new block,
 which we use to create a \code{goto}.
 \begin{lstlisting}
-(define (create_block block)
+(define (create_block tail)
   (delay
-    (define b (force block))
-    (match b
+    (define t (force tail))
+    (match t
       [(Goto label) (Goto label)]
-      [else (Goto (add-node b))])))
+      [else (Goto (add-node t))])))
 \end{lstlisting}
 \fi}
 {\if\edition\pythonEd