copy edit ch 6

book.tex

@@ -10359,9 +10359,9 @@ Although Python does not provide direct support for lazy evaluation, it
 is easy to mimic. We can \emph{delay} the evaluation of a computation
 by wrapping it inside a function with no parameters. We can
 \emph{force} its evaluation by calling the function. However, we might
-need to force multiple times, so we should memoize the result of
-calling the function. The following \code{Promise} class handles
-this memoization.
+need to force multiple times, so we should store the result of
+calling the function instead of recomputing the result each time.
+The following \code{Promise} class handles this memoization.
 %
 \begin{lstlisting}
 @dataclass
@@ -11023,7 +11023,7 @@ The $\VOID{}$ expression produces the \code{\#<void>} value.
 {\if\edition\pythonEd\pythonColor
 %
 We add a new case for \code{While} in the \code{interp\_stmts}
-function, where we repeatedly interpret the \code{body} so long as the
+function, in which we repeatedly interpret the \code{body} so long as the
 \code{test} expression remains true.
 %
 \fi}
@@ -11167,8 +11167,8 @@ class TypeCheckLwhile(TypeCheckLif):
 At first glance, the translation of these language features to x86
 seems straightforward because the \LangCIf{} intermediate language
 already supports all the ingredients that we need: assignment,
-\code{goto}, conditional branching, and sequencing. However, there are
-complications that arise, which we discuss in the next section. After
+\code{goto}, conditional branching, and sequencing. However, 
+complications arise, which we discuss in the next section. After
 that we introduce the changes necessary to the existing passes.
 %
 \fi}
@@ -11864,7 +11864,7 @@ other two have result type \code{Void}.
 {\if\edition\pythonEd\pythonColor
 %
 The output of this pass is the language \LangCIf{}. No new language
-features are needed in the output because a \code{while} loop can be
+features are needed in the output, because a \code{while} loop can be
 expressed in terms of \code{goto} and \code{if} statements, which are
 already in \LangCIf{}.
 %  
@@ -11917,7 +11917,7 @@ The \code{analyze\_dataflow} function has the following four parameters.
   \racket{Also, as a side effect, it should update the block's
     $\itm{info}$ with the liveness information for each instruction.}
   %
-  \python{Also, as a side-effect, it should update the live-before and
+  \python{Also, as a side effect, it should update the live-before and
     live-after sets for each instruction.}
   %
   To implement the \code{transfer} function, you should be able to
@@ -11929,7 +11929,7 @@ The \code{analyze\_dataflow} function has the following four parameters.
 \end{enumerate}
 
 
-\begin{figure}[p]
+\begin{figure}[tp]
 \begin{tcolorbox}[colback=white]      
 {\if\edition\racketEd
 \begin{tikzpicture}[baseline=(current  bounding  box.center),scale=0.90]