%% %% This is file `sample-manuscript.tex', %% generated with the docstrip utility. %% %% The original source files were: %% %% samples.dtx (with options: `manuscript') %% %% IMPORTANT NOTICE: %% %% For the copyright see the source file. %% %% Any modified versions of this file must be renamed %% with new filenames distinct from sample-manuscript.tex. %% %% For distribution of the original source see the terms %% for copying and modification in the file samples.dtx. %% %% This generated file may be distributed as long as the %% original source files, as listed above, are part of the %% same distribution. (The sources need not necessarily be %% in the same archive or directory.) %% %% Commands for TeXCount %TC:macro \cite [option:text,text] %TC:macro \citep [option:text,text] %TC:macro \citet [option:text,text] %TC:envir table 0 1 %TC:envir table* 0 1 %TC:envir tabular [ignore] word %TC:envir displaymath 0 word %TC:envir math 0 word %TC:envir comment 0 0 %% %% %% The first command in your LaTeX source must be the \documentclass command. \documentclass[manuscript,screen,review]{acmart} \usepackage{xcolor} \usepackage{listings} \usepackage[ligature, inference]{semantic} \usepackage{array} \definecolor{mGreen}{rgb}{0,0.6,0} \definecolor{mGray}{rgb}{0.5,0.5,0.5} \definecolor{mPurple}{rgb}{0.58,0,0.82} \definecolor{backgroundColour}{rgb}{0.95,0.95,0.92} \lstdefinestyle{CStyle}{ backgroundcolor=\color{backgroundColour}, commentstyle=\color{mGreen}, keywordstyle=\color{magenta}, numberstyle=\tiny\color{mGray}, stringstyle=\color{mPurple}, basicstyle=\footnotesize, breakatwhitespace=false, breaklines=true, captionpos=b, keepspaces=true, numbers=left, numbersep=5pt, showspaces=false, showstringspaces=false, showtabs=false, tabsize=2, language=C } %% %% \BibTeX command to typeset BibTeX logo in the docs \AtBeginDocument{% \providecommand\BibTeX{{% \normalfont B\kern-0.5em{\scshape i\kern-0.25em b}\kern-0.8em\TeX}}} %% %% Submission ID. %% Use this when submitting an article to a sponsored event. You'll %% receive a unique submission ID from the organizers %% of the event, and this ID should be used as the parameter to this command. %%\acmSubmissionID{123-A56-BU3} %% %% For managing citations, it is recommended to use bibliography %% files in BibTeX format. %% %% You can then either use BibTeX with the ACM-Reference-Format style, %% or BibLaTeX with the acmnumeric or acmauthoryear sytles, that include %% support for advanced citation of software artefact from the %% biblatex-software package, also separately available on CTAN. %% %% Look at the sample-*-biblatex.tex files for templates showcasing %% the biblatex styles. %% %% %% The majority of ACM publications use numbered citations and %% references. The command \citestyle{authoryear} switches to the %% "author year" style. %% %% If you are preparing content for an event %% sponsored by ACM SIGGRAPH, you must use the "author year" style of %% citations and references. %% Uncommenting %% the next command will enable that style. %%\citestyle{acmauthoryear} %% %% end of the preamble, start of the body of the document source. \begin{document} %% %% The "title" command has an optional parameter, %% allowing the author to define a "short title" to be used in page headers. \title{Enumeration in Cforall} %% %% The "author" command and its associated commands are used to define %% the authors and their affiliations. %% Of note is the shared affiliation of the first two authors, and the %% "authornote" and "authornotemark" commands %% used to denote shared contribution to the research. \author{Jiada Liang} %% %% The abstract is a short summary of the work to be presented in the %% article. \begin{abstract} An enumeration, or enum in short, is a type that defines a list of named constant values in C. Cforall extends the enumeration with additional features. \end{abstract} %% %% The code below is generated by the tool at http://dl.acm.org/ccs.cfm. %% Please copy and paste the code instead of the example below. %% %% %% This command processes the author and affiliation and title %% information and builds the first part of the formatted document. \maketitle \section{C-Style Enum} \begin{lstlisting}[style=CStyle] enum Weekday { Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday }; \end{lstlisting} Cforall supports the classic C-Style enumeration (C-enum for short) and its syntax is consistent with C. No internal data structure is generated for C-enum, and C-enum does not provide the Cforall-enum interface methods. \section{Cforall Enum} \subsection{Enumerable Type} \begin{lstlisting}[style=CStyle] forall(T) trait enumerable { void ?()( T & t, zero_t ); void ?()( T & t, one_t ); S& ?+=?( T & t, one_t ); void ?{}( T &, T ); T ?{}( T &, T ); }; \end{lstlisting} A type is enumerable in Cforall if it has defined 0, 1, increment operator, copy constructor, and copy assignment operator. (Should change the definition of enumerable to something else. Maybe auto-constructible. If a type is not auto-constructible, all enumeration must be explicitly initialized) \begin{lstlisting}[caption={An example enumerable type}, label{lst:sample_enumerable}, style=CStyle] struct Type { int i; }; void ?()( Type & t, zero_t ) { t.i = 0; }; void ?()( Type & t, one_t ) { t.i = 1; }; int ?!=?( Type t, zero_t ) { return t.i != 0; }; S& ?+=?( Type & t, one_t ) { t.i += 1; return t; }; void ?()( Type & t, Type rhs ) { t.i = rhs.i; }; Type ?()( Type & t, Type rhs ) { t.i = rhs.i; return t; }; \end{lstlisting} A Cforall-enum is a C-enum parameterized by an enumerable type. For example, $enum(int)$ turns a C-enum into a Cforall-enum. \begin{lstlisting}[caption={An example Cforall enum}, label{lst:sample_cforall_enum}, style=CStyle] enum Color(Type) { Red, Green, Blue }; > Type Color.values[] = { 0, values[0]++, values[1]++ }; > enum Color.Label { Red_Label, Green_Label, Blue_Label }; \end{lstlisting} Declaring a Cforall-enum, the compiler defines a C-enum names every element in the Cforall-enum, and an array that stores Cforall enumeration values. \subsection{Cforall Enumerations Behaviour} An instance of Cforall-enum (denoted as $$) has a label, the defined enum name. The label can be retrieved by calling the function $label()$ on a $$. The $value()$ function on the other hand returns the value used to initialize the Cforall-enum. Cforall-enum supports a qualified expression. The syntax of the qualified expression for Cforall-enum is $$.$$. In the $Color$ example, $Color$ is a $$ and $Red$, $Green$, $Blue$ are $$. \begin{lstlisting}[caption={An example Cforall enum}, label{lst:sample_cforall_enum_usage}, style=CStyle] enum Color red = Color.Red; > enum Color.Label red = = Color.Label.Red_Label; Type instance = Color.Red; > Type instance = Color.values[ Color.Label.Red_Label ]; \end{lstlisting} The expression $Color.Red$ is overloaded to represent both $value(Color.Red)$ and $label(Color.Red)$. The expression returns the $label(Color.Red)$ by default but returns $value()$ whenever the $value()$ is a closer candidate in the context. [more explanation] In \ref{lst:sample_cforall_enum_usage}, when assigned to an enum variable, $Color.Red$ returns the label. This is to reduce the memory to store a Cforall-enum variable. In an assignment expression when the left-hand-side expects a $Type$, the resolution finds $value(Color.Red)$ is a better candidate than $label(Color.Red)$, and returns the value instead. \subsection{Enum Type Functions} \begin{lstlisting}[caption={Enum Type Functions}, label{lst:cforall_enum_functions}, style=CStyle] enum Color(string) { // assume String has been defined as an enumerable type R = "Red", G = "Green", B = "Blue" }; values( Color ); > [ String("Red"), String("Green"), String("Blue") ]; label_strings( Color ); > [ "R", "G", "B" ]; enum Color green = Color.G; label_string( Color, green ); > "G" label( Color, green ); > 1 value( Color, green ) ; > "Green" value( Color, "G" ); > "Green" label( Color, "G" ); > 1 value( Color, "DNE" ); > (null) value( Color, 1 ); // "1" is the label "G" > "Green" \end{lstlisting} Names of labels are distinct in an enum declaration. Cforall therefore allows indexing an enum value with its string representation of a label. \subsection{Range Functions and Iteration (Placeholder)} \begin{lstlisting}[caption={Range Functions}, label{lst:range_functions}, style=CStyle] enum Weekday( Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday }; \end{lstlisting} \section{Implementation} \subsection{Companion Object} The intuition to create a companion object is that functions that support enumeration features need static information of an enumeration class. For example, values() returns an array of values defined for the enumeration. $label( Color, "G" )$ needs information about enum names defined for the enum class $Color$. Theoretically, enum-type functions can be defined as functions that take $TypeName$ expression as the first parameter. An alternative approach is to define that "companion object". \begin{lstlisting}[caption={Enum Type Functions}, label{lst:cforall_enum_functions}, style=CStyle] struct string; enum Color( string ) { R = "Red", G = "Green", B = "Blue" }; forall( T | enumerable(T) ) { struct Companion { T* values; char** labels; }; } >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Companion( string ) Color = { .values = [ "Red", "Green", "Blue" ], .labels = [ "R", "G", "B" ] }; >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> forall( T | enumerable(T) ) T* value( Companion, int ); char* label( Companion, int ); \end{lstlisting} \subsection{TODO - Type trait for Cforall - Enum} %% %% If your work has an appendix, this is the place to put it. \appendix \end{document} \endinput %% %% End of file `sample-manuscript.tex'.