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@@ -22,7 +22,7 @@
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\def\racketEd{0}
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\def\pythonEd{1}
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-\def\edition{1}
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+\def\edition{0}
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% material that is specific to the Racket edition of the book
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\newcommand{\racket}[1]{{\if\edition\racketEd{#1}\fi}}
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@@ -10058,13 +10058,12 @@ control-flow graphs of the later may contain cycles.
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\label{fig:c7-syntax}
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\end{figure}
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-The new auxiliary function \code{explicate\_effect} takes an expression
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-(in an effect position) and a promise of a continuation block. The
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-function returns a promise for a $\Tail$ that includes the generated
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-code for the input expression followed by the continuation block. If
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-the expression is obviously pure, that is, never causes side effects,
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-then the expression can be removed, so the result is just the
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-continuation block.
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+The new auxiliary function \code{explicate\_effect} takes an
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+expression (in an effect position) and a continuation. The function
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+returns a $\Tail$ that includes the generated code for the input
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+expression followed by the continuation. If the expression is
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+obviously pure, that is, never causes side effects, then the
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+expression can be removed, so the result is just the continuation.
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%
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The $\WHILE{\itm{cnd}}{\itm{body}}$ expression is the most interesting
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case. First, you will need a fresh label $\itm{loop}$ for the top of
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@@ -10074,9 +10073,7 @@ with the a \code{goto} to $\itm{loop}$ as the continuation, producing
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\itm{body'} as the then-branch and the continuation block as the
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else-branch. The result should be added to the control-flow graph with
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the label \itm{loop}. The result for the whole \code{while} loop is a
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-\code{goto} to the \itm{loop} label. Note that the loop should only be
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-added to the control-flow graph if the loop is indeed used, which can
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-be accomplished using \code{delay}.
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+\code{goto} to the \itm{loop} label.
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The auxiliary functions for tail, assignment, and predicate positions
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need to be updated. The three new language forms, \code{while},
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@@ -10105,9 +10102,9 @@ the condition expression.
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\label{sec:select-instructions-loop}
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Only three small additions are needed in the
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-\code{select\_instructions} pass to handle the changes to \LangCLoop{}. That
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-is, \code{Call}, \code{read}, and \code{vector-set!} may now appear as
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-stand-alone statements instead of only appearing on the right-hand
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+\code{select\_instructions} pass to handle the changes to
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+\LangCLoop{}. That is, a \code{Call} to \code{read} may now appear as a
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+stand-alone statement instead of only appearing on the right-hand
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side of an assignment statement. The code generation is nearly
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identical; just leave off the instruction for moving the result into
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the left-hand side.
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Jeremy Siek