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@@ -956,11 +956,12 @@ In the next section we see our first example of a compiler.
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\section{Example Compiler: a Partial Evaluator}
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\label{sec:partial-evaluation}
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-In this section we consider a compiler that translates $R_0$
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-programs into $R_0$ programs that may be more efficient, that is,
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-this compiler is an optimizer. Our optimizer will accomplish this by
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-trying to eagerly compute the parts of the program that do not depend
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-on any inputs. For example, given the following program
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+In this section we consider a compiler that translates $R_0$ programs
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+into $R_0$ programs that may be more efficient, that is, this compiler
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+is an optimizer. This optimizer eagerly computes the parts of the
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+program that do not depend on any inputs, a process known as
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+\emph{partial evaluation}~\cite{Jones:1993uq}. For example, given the
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+following program
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\begin{lstlisting}
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(+ (read) (- (+ 5 3)))
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\end{lstlisting}
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@@ -1009,9 +1010,8 @@ functions is the output of partially evaluating the children.
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The \texttt{pe-neg} and \texttt{pe-add} functions check whether their
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arguments are integers and if they are, perform the appropriate
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-arithmetic. Otherwise, they use quasiquote to create an AST node for
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-the operation (either negation or addition) and use comma to splice in
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-the children.
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+arithmetic. Otherwise, they create an AST node for the operation
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+(either negation or addition).
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To gain some confidence that the partial evaluator is correct, we can
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test whether it produces programs that get the same result as the
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@@ -7837,8 +7837,11 @@ The utility function described in this section can be found in the
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\key{utilities.rkt} file.
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The \key{read-program} function takes a file path and parses that file
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-(it must be a Racket program) into an abstract syntax tree (as an
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-S-expression) with a \key{program} AST at the top.
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+(it must be a Racket program) into an abstract syntax tree with a
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+\key{Program} node at the top.
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+
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+The \key{parse-program} function takes an S-expression representation
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+of an AST and converts it into the struct-based representation.
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The \key{assert} function displays the error message \key{msg} if the
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Boolean \key{bool} is false.
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Jeremy Siek