tweaks

book.tex

@@ -6,10 +6,9 @@
 %%   * adding letrec to the language
 %%     (Thought: in the book and regular course, replace top-level defines
 %%      with letrec.)
-%%   * alternative back ends (ARM, LLVM)
+%%   * alternative back ends (ARM!, LLVM)
 %%   * alternative calling convention (a la Dybvig)
 %%   * lazy evaluation
-%%   * gradual typing
 %%   * continuations (frames in heap a la SML or segmented stack a la Dybvig)
 %%   * exceptions
 %%   * self hosting
@@ -19,17 +18,15 @@
 %%   * macros (too difficult?)
 %%   * alternative garbage collector
 %%   * alternative register allocator
-%%   * parametric polymorphism
-%%   * type classes (too difficulty?)
-%%   * loops (too easy? combine with something else?)
+%%   * type classes
 %%   * loop optimization (fusion, etc.)
 %%   * deforestation
-%%   * records and subtyping
+%%   * records with subtyping
 %%   * object-oriented features
 %%     - objects, object types, and structural subtyping (e.g. Abadi & Cardelli)
 %%     - class-based objects and nominal subtyping (e.g. Featherweight Java)
 %%   * multi-threading, fork join, futures, implicit parallelism
-%%   * dataflow analysis, type analysis and specialization
+%%   * type analysis and specialization
 
 
 \documentclass[11pt]{book}
@@ -225,8 +222,8 @@ the students learned a lot and got excited about compilers.
 
 I returned to Indiana University in 2013.  In my absence the compiler
 course had switched from the front-to-back organization to a
-back-to-front organization~\cite{Dybvig:2010aa}. Seeing how well the
-incremental approach worked at Colorado, I started porting and
+back-to-front~\cite{Dybvig:2010aa}. While that organization also works
+well, I prefer the incremental approach and started porting and
 adapting the structure of the Colorado course back into the land of
 Scheme. In the meantime Indiana University had moved on from Scheme to
 Racket~\citep{plt-tr}, so the course is now about compiling a subset
@@ -2618,21 +2615,20 @@ The next exercise builds on Exercise~\ref{ex:pe-R1}.
 Improve on the partial evaluator by replacing the \code{pe-neg} and
 \code{pe-add} auxiliary functions with functions that know more about
 arithmetic. For example, your partial evaluator should translate
-\begin{lstlisting}
-(+ 1 (+ (read) 1))
-\end{lstlisting}
-into
-\begin{lstlisting}
-(+ 2 (read))
-\end{lstlisting}
+\[
+\code{(+ 1 (+ (read) 1))} \qquad \text{into} \qquad
+\code{(+ 2 (read))}
+\]
 To accomplish this, the \code{pe-exp} function should produce output
 in the form of the $\itm{residual}$ non-terminal of the following
 grammar.
 \[
 \begin{array}{lcl}
-\itm{inert} &::=& \Var \mid (\key{read}) \mid (\key{-} \;(\key{read}))
-      \mid (\key{+} \; \itm{inert} \; \itm{inert})\\
-\itm{residual} &::=& \Int \mid (\key{+}\; \Int\; \itm{inert}) \mid \itm{inert}
+\itm{inert} &::=& \Var \mid \LP\key{read}\RP \mid \LP\key{-} \;\Var\RP
+    \mid \LP\key{-} \;\LP\key{read}\RP\RP
+    \mid \LP\key{+} \; \itm{inert} \; \itm{inert}\RP\\
+  &\mid& \LP\key{let}~\LP\LS\Var~\itm{inert}\RS\RP~ \itm{inert} \RP \\
+\itm{residual} &::=& \Int \mid \LP\key{+}\; \Int\; \itm{inert}\RP \mid \itm{inert} 
 \end{array}
 \]
 The \code{pe-add} and \code{pe-neg} functions may therefore assume
@@ -11016,7 +11012,6 @@ The \code{analyze-dataflow} function has four parameters.
 Figure~\ref{fig:R8-passes} provides an overview of all the passes needed
 for the compilation of $R_8$.
 
-
 % TODO: challenge assignment
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -12176,6 +12171,9 @@ recommend the reader to the online gradual typing bibliography:
   \url{http://samth.github.io/gradual-typing-bib/}
 \end{center}
 
+% TODO: challenge problem:
+%   type analysis and type specialization?
+%   coercions?
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \chapter{Parametric Polymorphism}
@@ -12801,13 +12799,7 @@ annotations and the body.
 Figure~\ref{fig:R10-passes} provides an overview of all the passes needed
 for the compilation of $R_{10}$.
 
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-%% \chapter{High-level Optimization}
-%% \label{ch:high-level-optimization}
-
-%% This chapter will present a procedure inlining pass based on the
-%% algorithm of \citet{Waddell:1997fk}.
-
+% TODO: challenge problem: specialization of instantiations
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \chapter{Appendix}