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@@ -105,8 +105,72 @@ University.
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\chapter*{Preface}
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-Talk about nano-pass \citep{Sarkar:2004fk,Keep:2012aa} and incremental
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-compilers \citep{Ghuloum:2006bh}.
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+The tradition of compiler writing at Indiana University goes back to
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+programming language research and courses taught by Daniel Friedman in
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+the 1970's. Dan had conducted research on lazy evaluation in the
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+context of Lisp~\citep{McCarthy:1960dz} and then studied continuations
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+and macros in the context of the Scheme~\citep{Sussman:1975ab}, a
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+dialect of Lisp. One of students of those courses, Kent Dybvig, went
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+on to build Chez Scheme~\citep{Dybvig:2006aa}, a production-quality
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+and efficient compiler for Scheme. After completing his Ph.D. at the
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+University of North Carolina, Kent returned to teach at Indiana
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+University. Throughout the 1990's and early 2000's, Kent continued
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+development of Chez Scheme and rotated with Dan in teaching the
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+compiler course.
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+
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+Thanks to this collaboration between Dan and Kent, the compiler course
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+evolved to incorporate novel pedagogical ideas while also including
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+elements of effective real-world compilers. One of the pedagogical
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+ideas was to split the compiler into many small passes over the input
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+program and subsequent intermediate representations, so that the code
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+for each pass is easy to understood in isolation. (In contrast, most
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+compilers of the time were organized into only a few large passes for
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+reasons of compile-time efficiency.) Kent and his students, Dipanwita
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+Sarkar and Andrew Keep, developed infrastructure to support this
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+approach and evolved the course, first to use micro-sized passes and
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+then into even smaller
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+nano-passes~\citep{Sarkar:2004fk,Keep:2012aa}. I took this compiler
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+course in the early 2000's, as part of my Ph.D. studies at Indiana
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+University.
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+
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+One of my classmates, Abdulaziz Ghuloum, observed that the
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+front-to-back organization of the course made it difficult for
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+students to understand the rationale for the compiler
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+design. Abdulaziz proposed an incremental approach in which the
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+students build the compiler in stages, starting by implementing a
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+complete compiler for a very small subset of the input language, then
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+gradually adding features to the input language and adding or
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+modifying passes to handle those features~\citep{Ghuloum:2006bh}.
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+
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+After graduating from Indiana University in 2005, I went on to teach
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+at the University of Colorado. I adapted the nano-pass and incremental
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+approaches to compiling a subset of the Python
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+language~\citep{Siek:2012ab}. Python and Scheme are quite different
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+on the surface but there is a large overlap in the compiler techniques
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+required for the two languages. Thus, I was able to teach much of the
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+same content from the Indiana compiler course. I very much enjoyed
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+teaching the course organized according to the nano-pass and
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+incremental approaches, and even better, many of the students learned
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+a lot and got excited about compilers. (No, I didn't do a
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+quantitative study to support this claim.)
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+
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+It is now 2016 and I too have returned to teach at Indiana University.
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+In my absence the compiler course had switched from the front-to-back
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+organization to a back-to-front organization. Seeing how well the
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+incremental approach worked at Colorado, I found this rather
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+unsatisfactory and have therefore proceeded to reorganize the course,
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+porting and adapting the structure of the Colorado course back into
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+the land of Scheme. Of course, in the meantime Scheme has been
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+superseded by Racket (at least in Indiana), so the course is now about
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+implementing, in Racket~\citep{plt-tr}, a subset of Racket.
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+
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+This is the textbook for the incremental version of the compiler
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+course at Indiana Unversity. This book would have been better written
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+by Dan, Kent, and Abdulaziz, but it seems that I am the one with the
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+time and enthusiasm. With this book I hope to make the Indiana
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+compiler course available to people that have not had the chance to
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+study here in person.
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+
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Talk about pre-requisites.
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@@ -132,12 +196,13 @@ Need to give thanks to
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\item Abdulaziz Ghuloum
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\item Ryan Newton
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\item Dipanwita Sarkar
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+\item Andrew Keep
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\item Oscar Waddell
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\end{itemize}
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-%\mbox{}\\
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-%\noindent Amber Jain \\
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-%\noindent \url{http://amberj.devio.us/}
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+\mbox{}\\
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+\noindent Jeremy G. Siek \\
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+\noindent \url{http://homes.soic.indiana.edu/jsiek}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\chapter{Preliminaries}
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@@ -300,7 +365,7 @@ R_0 ::= \Int \mid ({\tt \key{read}}) \mid (\key{-} \; R_0) \mid
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\section{S-Expressions}
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\label{sec:s-expr}
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-Racket, as a descendant of Lisp~\citep{McCarthy:1960dz}, has
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+Racket, as a descendant of Lisp, has
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convenient support for creating and manipulating abstract syntax trees
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with its \emph{symbolic expression} feature, or S-expression for
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short. We can create an S-expression simply by writing a backquote
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@@ -528,6 +593,7 @@ of evaluation can make a different.
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The behavior of the following program is somewhat subtle because
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Racket does not specify an evaluation order for arguments of an
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operator such as $-$.
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+\marginpar{\scriptsize This is not true of Racket. \\ --Jeremy}
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\[
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\BINOP{+}{\READ}{\UNIOP{-}{\READ}}
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\]
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Jeremy Siek