minor edit

book.tex

@@ -3553,21 +3553,22 @@ The \key{map2} function ...
 The \code{make-graph}, \code{add-edge}, and \code{adjacent}
 functions...
 
-The \key{interp-tests} function takes a compiler name (a string) a
-description of the passes a test family name (a string), and a list of
-test numbers, and runs the compiler passes and the interpreters to
-check whether the passes correct. The description of the passes is a
-list with one entry per pass.  An entry is a list with three things: a
-string giving the name of the pass, the function that implements the
-pass (a translator from AST to AST), and a function that implements
-the interpreter (a function from AST to result value).  The
-interpreters from Appendix~\ref{appendix:interp} make a good choice.
-The \key{interp-tests} function assumes that the subdirectory
-\key{tests} has a bunch of Scheme programs whose names all start with
-the family name, followed by an underscore and then the test number,
-ending in \key{.scm}. Also, for each Scheme program there is a file
-with the same number except that it ends with \key{.in} that provides
-the input for the Scheme program.
+The \key{interp-tests} function takes a compiler name (a string), a
+description of the passes, an interpreter for the source language, a
+test family name (a string), and a list of test numbers, and runs the
+compiler passes and the interpreters to check whether the passes
+correct. The description of the passes is a list with one entry per
+pass.  An entry is a list with three things: a string giving the name
+of the pass, the function that implements the pass (a translator from
+AST to AST), and a function that implements the interpreter (a
+function from AST to result value) for the language of the output of
+the pass.  The interpreters from Appendix~\ref{appendix:interp} make a
+good choice.  The \key{interp-tests} function assumes that the
+subdirectory \key{tests} has a bunch of Scheme programs whose names
+all start with the family name, followed by an underscore and then the
+test number, ending in \key{.scm}. Also, for each Scheme program there
+is a file with the same number except that it ends with \key{.in} that
+provides the input for the Scheme program.
 \begin{lstlisting}
 (define (interp-tests name passes test-family test-nums) ...
 \end{lstlisting}