New.

Geoffrey Challen
1 parent 08f18b2b
Showing 1 changed file with 24 additions and 32 deletions
maybe.tex
@@ -3,8 +3,8 @@
 To begin we provide an overview of the \texttt{maybe} statements semantics,
 describing how it structures uncertainty in variable values and runtime
-execution. We refer to each of the values a \texttt{maybe} variable can take
-or paths a \texttt{maybe} code block can execute as an \textit{alternative}.
+execution. We refer to each of the values or code paths a \texttt{maybe}
+statement can choose from as an \textit{alternative}.
 \begin{figure}[t]
 \begin{minted}[fontsize=\footnotesize]{java}
@@ -22,23 +22,18 @@ int myFunction(int a) { /* Second alternative */ }
 // Inlining evaluation code
 maybe {
 ret = fastPowerHungryAlgorithm(input);
- choice = FAST;
 } or {
 ret = slowPowerEfficientAlgorithm(input);
- choice = SLOW;
 } analyze {
 return { "repeat": false,
 "score" : nanoTime() + powerDrain() }
 }
-// Cleanup may depend on which algorithm was used
-if(choice == FAST){ cleanUpAfterFastAlg(ret); }
-else { cleanUpAfterSlowAlg(ret); }
 \end{minted}
 \vspace*{-0.2in}
-\caption{\textbf{More Examples of \texttt{maybe} Statements.}}
+\caption{\textbf{More \texttt{maybe} Statements}}
 \label{fig-maybeexamples}
@@ -70,36 +65,33 @@ or reorganize logic that does not affect correctness, but may (or
 may not) improve performance if executed.
 Figure~\ref{fig-maybeexamples} shows several extensions of the \texttt{maybe}
-statement providing syntactic sugar. \texttt{maybe} function annotations allow
-uncertainty to be expressed at the function level, with the alternatives
-consisting of multiple function definitions with identical signatures. Finally,
-\texttt{maybe} blocks that require special performance evaluation logic can 
-include that in the form of a \texttt{better} statement following the main 
-\texttt{maybe}
-block, as shown in the final example. \texttt{better} blocks provide 
-application-specific logic that performs a post-mortem on the selected 
-execution path. The \texttt{better} block must return a
-single JSON object that includes two components: A score, with smaller being
-interpreted as better; and a boolean indicating whether the system should
-use the same branch next time, or if it is free to try another. 
-Note that hints and dedicated evaluation logic can also be
-applied to variable and function-level \texttt{maybe} statements through
-annotations.
-We will return to post-mortem evaluation 
-in Section~\ref{sec-certainty}.
+statement providing syntactic sugar. \texttt{maybe} function annotations
+allow uncertainty to be expressed at the function level, with the
+alternatives consisting of multiple function definitions with identical
+signatures. Finally, \texttt{maybe} blocks that require special performance
+evaluation logic can include that in the form of a \texttt{better} statement
+following the main \texttt{maybe} block, as shown in the final example.
+\texttt{better} blocks provide application-specific logic that analyze the
+selected execution path. The \texttt{better} block must return a single JSON
+object that includes two components: A score, with smaller being interpreted
+as better; and a boolean indicating whether the system should use the same
+branch next time, or if it is free to try another. Note that hints and
+dedicated evaluation logic can also be applied to variable and function-level
+\texttt{maybe} statements through annotations. We will return to post-mortem
+evaluation in Section~\ref{sec-certainty}.
 \subsection{Discussion}
-We have yet to determine how well programmers will be able to use the new
-\texttt{maybe} construct. At some level, \texttt{maybe} statements are
-similar to the common \texttt{if-else} construct in that at the bottom of the
+We have yet to determine how well programmers will be able to use the
+\texttt{maybe} statement. Structurally \texttt{maybe} statements are similar
+to the common \texttt{if-else} construct in that at the bottom of the
 statement the programmer may not be sure which block was executed. However,
 while with \texttt{if-else} blocks it can be determined which block was
 executed by examining the branch conditions, \texttt{maybe} statements
-require developers record which alternative was used if downstream code
-depends on the decision. Alternatively, programmers may use a \texttt{maybe}
-variable to select a policy and employ traditional \texttt{if-else}
-statements to direct control flow based on the \texttt{maybe} variable.
+require developers record which alternative was executed if downstream code
+depends on the decision. To coordinate the adaptation of multiple code paths
+a single \texttt{maybe} variable can be used to control multiple
+\texttt{if-else} statements.
 While \texttt{maybe} is a powerful programming tool, it is important that it
 be used sparingly. In the case where dependencies exist between the