|
|
@@ -13,6 +13,11 @@
|
|
|
\usepackage{multirow}
|
|
|
\usepackage{tcolorbox}
|
|
|
\usepackage{color}
|
|
|
+%\usepackage{ifthen}
|
|
|
+
|
|
|
+\def\edition{1}
|
|
|
+\def\racketEd{0}
|
|
|
+\def\pythonEd{1}
|
|
|
|
|
|
\definecolor{lightgray}{gray}{1}
|
|
|
\newcommand{\black}[1]{{\color{black} #1}}
|
|
|
@@ -308,7 +313,7 @@ Racket~\citep{Dybvig:1987aa,Abelson:1996uq,Friedman:1996aa,Felleisen:2001aa,Fell
|
|
|
This edition of the book uses the \href{https://www.python.org/}{Python}
|
|
|
both for the implementation of the compiler and for the input language, so the
|
|
|
reader should be proficient with Python. There are many
|
|
|
-excellent resources for learning Python~\citep{}.
|
|
|
+excellent resources for learning Python~\citep{Lutz:2013vp,Barry:2016vj,Sweigart:2019vn,Matthes:2019vs}.
|
|
|
}
|
|
|
The support code for this book is in the \code{github} repository at
|
|
|
the following URL:
|
|
|
@@ -375,7 +380,7 @@ invaluable feedback.
|
|
|
|
|
|
We thank Ronald Garcia for helping Jeremy survive Dybvig's compiler
|
|
|
course in the early 2000's and especially for finding the bug that
|
|
|
-sent the garbage collector on a wild goose chase!
|
|
|
+sent our garbage collector on a wild goose chase!
|
|
|
|
|
|
\mbox{}\\
|
|
|
\noindent Jeremy G. Siek \\
|
|
|
@@ -398,23 +403,35 @@ perform.\index{subject}{concrete syntax}\index{subject}{abstract syntax}\index{s
|
|
|
syntax tree}\index{subject}{AST}\index{subject}{program}\index{subject}{parse} The translation
|
|
|
from concrete syntax to abstract syntax is a process called
|
|
|
\emph{parsing}~\citep{Aho:1986qf}. We do not cover the theory and
|
|
|
-implementation of parsing in this book. A parser is provided in the
|
|
|
-support code for translating from concrete to abstract syntax.
|
|
|
+implementation of parsing in this book.
|
|
|
+%
|
|
|
+\racket{A parser is provided in the support code for translating from
|
|
|
+ concrete to abstract syntax.}
|
|
|
+%
|
|
|
+\python{We use Python's \code{ast} module to translate from concrete
|
|
|
+ to abstract syntax.}
|
|
|
|
|
|
ASTs can be represented in many different ways inside the compiler,
|
|
|
depending on the programming language used to write the compiler.
|
|
|
%
|
|
|
-We use Racket's
|
|
|
+\racket{We use Racket's
|
|
|
\href{https://docs.racket-lang.org/guide/define-struct.html}{\code{struct}}
|
|
|
-feature to represent ASTs (Section~\ref{sec:ast}). We use grammars to
|
|
|
-define the abstract syntax of programming languages
|
|
|
+feature to represent ASTs (Section~\ref{sec:ast}).}
|
|
|
+%
|
|
|
+\python{We use Python classes and objects to represent ASTs, especially the
|
|
|
+ classes defined in the standard \code{ast} module for the Python
|
|
|
+ source language.}
|
|
|
+%
|
|
|
+We use grammars to define the abstract syntax of programming languages
|
|
|
(Section~\ref{sec:grammar}) and pattern matching to inspect individual
|
|
|
nodes in an AST (Section~\ref{sec:pattern-matching}). We use
|
|
|
recursive functions to construct and deconstruct ASTs
|
|
|
(Section~\ref{sec:recursion}). This chapter provides an brief
|
|
|
-introduction to these ideas. \index{subject}{struct}
|
|
|
+introduction to these ideas.
|
|
|
+\racket{\index{subject}{struct}}
|
|
|
+\python{\index{subject}{class}\index{subject}{object}}
|
|
|
|
|
|
-\section{Abstract Syntax Trees and Racket Structures}
|
|
|
+\section{Abstract Syntax Trees}
|
|
|
\label{sec:ast}
|
|
|
|
|
|
Compilers use abstract syntax trees to represent programs because they
|
|
|
@@ -427,15 +444,22 @@ negation. The negation has another sub-part, the integer constant
|
|
|
follow the links to go from one part of a program to its sub-parts.
|
|
|
\begin{center}
|
|
|
\begin{minipage}{0.4\textwidth}
|
|
|
+\if\edition\racketEd
|
|
|
\begin{lstlisting}
|
|
|
(+ (read) (- 8))
|
|
|
\end{lstlisting}
|
|
|
+\fi
|
|
|
+\if\edition\pythonEd
|
|
|
+\begin{lstlisting}
|
|
|
+input_int() + -8
|
|
|
+\end{lstlisting}
|
|
|
+\fi
|
|
|
\end{minipage}
|
|
|
\begin{minipage}{0.4\textwidth}
|
|
|
\begin{equation}
|
|
|
\begin{tikzpicture}
|
|
|
\node[draw, circle] (plus) at (0 , 0) {\key{+}};
|
|
|
- \node[draw, circle] (read) at (-1, -1.5) {{\footnotesize\key{read}}};
|
|
|
+ \node[draw, circle] (read) at (-1, -1.5) {{\if\edition\racketEd\footnotesize\key{read}\fi\if\edition\pythonEd\key{input}}};
|
|
|
\node[draw, circle] (minus) at (1 , -1.5) {$\key{-}$};
|
|
|
\node[draw, circle] (8) at (1 , -3) {\key{8}};
|
|
|
|
Jeremy Siek