source: doc/theses/jiada_liang_MMath/main.tex @ 85034ed

%%
%% 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 $<enum\_instance>$) has a label, the defined enum name. The label can be retrieved by calling the function $label()$ on a $<enum\_instance>$. 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 $$<enum\_type\_name>.<enum\_instance\_name>$$. In the $Color$ example, $Color$ is a $<enum\_type\_name>$ and $Red$, $Green$, $Blue$ are $<enum\_instance\_name>$. 

\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'.