check

book.tex

@@ -6440,18 +6440,23 @@ $\Rightarrow$
 %
 In addition to transforming each \key{lambda} into a \key{vector}, we
 must create a top-level function definition for each \key{lambda}, as
-shown below.
-\begin{lstlisting}
-   (define (|\itm{name}| [clos : _] |\itm{ps}| ...)
+shown below.\\
+\begin{minipage}{0.8\textwidth}
+  \begin{lstlisting}
+   (define (|\itm{name}| [clos : (Vector _ |\itm{fvts}| ...)] |\itm{ps}| ...)
       (let ([|$\itm{fvs}_1$| (vector-ref clos 1)])
         ...
         (let ([|$\itm{fvs}_n$| (vector-ref clos |$n$|)])
           |\itm{body'}|)...))
 \end{lstlisting}
+\end{minipage}\\
 The \code{clos} parameter refers to the closure whereas $\itm{ps}$ are
-the normal parameters of the \key{lambda}. The sequence of \key{let}
-forms being the free variables to their values obtained from the
-closure.
+the normal parameters of the \key{lambda}. The types $\itm{fvts}$ are
+the types of the free variables in the lambda and the underscore is a
+dummy type because it is rather difficult to give a type to the
+function in the closure's type, and it does not matter.  The sequence
+of \key{let} forms being the free variables to their values obtained
+from the closure.
 
 We transform function application into code that retreives the
 function pointer from the closure and then calls the function, passing