Changeset 95b3a9c for doc/user/user.tex


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Timestamp:
Feb 17, 2021, 12:45:36 PM (3 years ago)
Author:
Thierry Delisle <tdelisle@…>
Branches:
ADT, arm-eh, ast-experimental, enum, forall-pointer-decay, jacob/cs343-translation, master, new-ast-unique-expr, pthread-emulation, qualifiedEnum
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e7c077a
Parents:
5e99a9a (diff), 9fb1367 (diff)
Note: this is a merge changeset, the changes displayed below correspond to the merge itself.
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Message:

Merge branch 'master' of plg.uwaterloo.ca:software/cfa/cfa-cc

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  • doc/user/user.tex

    r5e99a9a r95b3a9c  
    1111%% Created On       : Wed Apr  6 14:53:29 2016
    1212%% Last Modified By : Peter A. Buhr
    13 %% Last Modified On : Mon Oct  5 08:57:29 2020
    14 %% Update Count     : 3998
     13%% Last Modified On : Mon Feb 15 13:48:53 2021
     14%% Update Count     : 4452
    1515%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    1616
     
    3737\usepackage{mathptmx}                                   % better math font with "times"
    3838\usepackage[usenames]{color}
     39\usepackage[dvips,plainpages=false,pdfpagelabels,pdfpagemode=UseNone,colorlinks=true,pagebackref=true,linkcolor=blue,citecolor=blue,urlcolor=blue,pagebackref=true,breaklinks=true]{hyperref}
     40\usepackage{breakurl}
     41
     42\renewcommand\footnoterule{\kern -3pt\rule{0.3\linewidth}{0.15pt}\kern 2pt}
     43
     44\usepackage[pagewise]{lineno}
     45\renewcommand{\linenumberfont}{\scriptsize\sffamily}
     46\usepackage[firstpage]{draftwatermark}
     47\SetWatermarkLightness{0.9}
     48
     49% Default underscore is too low and wide. Cannot use lstlisting "literate" as replacing underscore
     50% removes it as a variable-name character so keywords in variables are highlighted. MUST APPEAR
     51% AFTER HYPERREF.
     52\renewcommand{\textunderscore}{\leavevmode\makebox[1.2ex][c]{\rule{1ex}{0.075ex}}}
     53
     54\setlength{\topmargin}{-0.45in}                                                 % move running title into header
     55\setlength{\headsep}{0.25in}
     56
     57%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     58
    3959\newcommand{\CFALatin}{}
    4060% inline code ©...© (copyright symbol) emacs: C-q M-)
     
    4666% math escape $...$ (dollar symbol)
    4767\input{common}                                          % common CFA document macros
    48 \usepackage[dvips,plainpages=false,pdfpagelabels,pdfpagemode=UseNone,colorlinks=true,pagebackref=true,linkcolor=blue,citecolor=blue,urlcolor=blue,pagebackref=true,breaklinks=true]{hyperref}
    49 \usepackage{breakurl}
    50 
    51 \renewcommand\footnoterule{\kern -3pt\rule{0.3\linewidth}{0.15pt}\kern 2pt}
    52 
    53 \usepackage[pagewise]{lineno}
    54 \renewcommand{\linenumberfont}{\scriptsize\sffamily}
    55 \usepackage[firstpage]{draftwatermark}
    56 \SetWatermarkLightness{0.9}
    57 
    58 % Default underscore is too low and wide. Cannot use lstlisting "literate" as replacing underscore
    59 % removes it as a variable-name character so keywords in variables are highlighted. MUST APPEAR
    60 % AFTER HYPERREF.
    61 \renewcommand{\textunderscore}{\leavevmode\makebox[1.2ex][c]{\rule{1ex}{0.075ex}}}
    62 
    63 \setlength{\topmargin}{-0.45in}                                                 % move running title into header
    64 \setlength{\headsep}{0.25in}
    65 
    66 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    67 
    6868\CFAStyle                                                                                               % use default CFA format-style
     69\lstset{language=CFA}                                                                   % CFA default lnaguage
    6970\lstnewenvironment{C++}[1][]                            % use C++ style
    70 {\lstset{language=C++,moredelim=**[is][\protect\color{red}]{®}{®},#1}}
     71{\lstset{language=C++,moredelim=**[is][\protect\color{red}]{@}{@},#1}}
    7172{}
    7273
     
    8182\newcommand{\Emph}[2][red]{{\color{#1}\textbf{\emph{#2}}}}
    8283\newcommand{\R}[1]{\Textbf{#1}}
     84\newcommand{\RC}[1]{\Textbf{\LstBasicStyle{#1}}}
    8385\newcommand{\B}[1]{{\Textbf[blue]{#1}}}
    8486\newcommand{\G}[1]{{\Textbf[OliveGreen]{#1}}}
     
    103105
    104106\author{
    105 \huge \CFA Team \medskip \\
    106 \Large Andrew Beach, Richard Bilson, Peter A. Buhr, Thierry Delisle, \smallskip \\
    107 \Large Glen Ditchfield, Rodolfo G. Esteves, Aaron Moss, Rob Schluntz
     107\huge \CFA Team (past and present) \medskip \\
     108\Large Andrew Beach, Richard Bilson, Michael Brooks, Peter A. Buhr, Thierry Delisle, \smallskip \\
     109\Large Glen Ditchfield, Rodolfo G. Esteves, Aaron Moss, Colby Parsons, Rob Schluntz, \smallskip \\
     110\Large Fangren Yu, Mubeen Zulfiqar
    108111}% author
    109112
     
    126129\vspace*{\fill}
    127130\noindent
    128 \copyright\,2016 \CFA Project \\ \\
     131\copyright\,2016, 2018, 2021 \CFA Project \\ \\
    129132\noindent
    130133This work is licensed under the Creative Commons Attribution 4.0 International License.
     
    144147\section{Introduction}
    145148
    146 \CFA{}\index{cforall@\CFA}\footnote{Pronounced ``\Index*{C-for-all}'', and written \CFA, CFA, or \CFL.} is a modern general-purpose programming-language, designed as an evolutionary step forward for the C programming language.
     149\CFA{}\index{cforall@\CFA}\footnote{Pronounced ``\Index*{C-for-all}'', and written \CFA, CFA, or \CFL.} is a modern general-purpose concurrent programming-language, designed as an evolutionary step forward for the C programming language.
    147150The syntax of \CFA builds from C and should look immediately familiar to C/\Index*[C++]{\CC{}} programmers.
    148151% Any language feature that is not described here can be assumed to be using the standard \Celeven syntax.
    149 \CFA adds many modern programming-language features that directly lead to increased \emph{\Index{safety}} and \emph{\Index{productivity}}, while maintaining interoperability with existing C programs and achieving similar performance.
     152\CFA adds many modern features that directly lead to increased \emph{\Index{safety}} and \emph{\Index{productivity}}, while maintaining interoperability with existing C programs and achieving similar performance.
    150153Like C, \CFA is a statically typed, procedural (non-\Index{object-oriented}) language with a low-overhead runtime, meaning there is no global \Index{garbage-collection}, but \Index{regional garbage-collection}\index{garbage-collection!regional} is possible.
    151154The primary new features include polymorphic routines and types, exceptions, concurrency, and modules.
     
    157160instead, a programmer evolves a legacy program into \CFA by incrementally incorporating \CFA features.
    158161As well, new programs can be written in \CFA using a combination of C and \CFA features.
     162In many ways, \CFA is to C as \Index{Scala}~\cite{Scala} is to Java, providing a vehicle for new typing and control-flow capabilities on top of a highly popular programming language allowing immediate dissemination.
    159163
    160164\Index*[C++]{\CC{}}~\cite{c++:v1} had a similar goal 30 years ago, allowing object-oriented programming to be incrementally added to C.
     
    165169For example, the following programs compare the C, \CFA, and \CC I/O mechanisms, where the programs output the same result.
    166170\begin{center}
    167 \begin{tabular}{@{}l@{\hspace{1.5em}}l@{\hspace{1.5em}}l@{}}
    168 \multicolumn{1}{c@{\hspace{1.5em}}}{\textbf{C}} & \multicolumn{1}{c}{\textbf{\CFA}}     & \multicolumn{1}{c}{\textbf{\CC}}      \\
    169 \begin{cfa}
    170 #include <stdio.h>§\indexc{stdio.h}§
     171\begin{tabular}{@{}l@{\hspace{1em}}l@{\hspace{1em}}l@{}}
     172\multicolumn{1}{c@{\hspace{1em}}}{\textbf{C}}   & \multicolumn{1}{c}{\textbf{\CFA}}     & \multicolumn{1}{c}{\textbf{\CC}}      \\
     173\begin{cfa}
     174#include <stdio.h>$\indexc{stdio.h}$
    171175
    172176int main( void ) {
    173177        int x = 0, y = 1, z = 2;
    174         ®printf( "%d %d %d\n", x, y, z );®
     178        @printf( "%d %d %d\n", x, y, z );@
    175179}
    176180\end{cfa}
    177181&
    178182\begin{cfa}
    179 #include <fstream>§\indexc{fstream}§
     183#include <fstream>$\indexc{fstream}$
    180184
    181185int main( void ) {
    182186        int x = 0, y = 1, z = 2;
    183         ®sout | x | y | z;®§\indexc{sout}§
     187        @sout | x | y | z;@$\indexc{sout}$
    184188}
    185189\end{cfa}
    186190&
    187191\begin{cfa}
    188 #include <iostream>§\indexc{iostream}§
     192#include <iostream>$\indexc{iostream}$
    189193using namespace std;
    190194int main() {
    191195        int x = 0, y = 1, z = 2;
    192         ®cout<<x<<" "<<y<<" "<<z<<endl;®
     196        @cout<<x<<" "<<y<<" "<<z<<endl;@
    193197}
    194198\end{cfa}
    195199\end{tabular}
    196200\end{center}
    197 While the \CFA I/O looks similar to the \Index*[C++]{\CC{}} output style, there are important differences, such as automatic spacing between variables as in \Index*{Python} (see~\VRef{s:IOLibrary}).
     201While \CFA I/O \see{\VRef{s:StreamIOLibrary}} looks similar to \Index*[C++]{\CC{}}, there are important differences, such as automatic spacing between variables and an implicit newline at the end of the expression list, similar to \Index*{Python}~\cite{Python}.
    198202
    199203
     
    210214\section{Why fix C?}
    211215
    212 The C programming language is a foundational technology for modern computing with millions of lines of code implementing everything from hobby projects to commercial operating-systems.
     216The C programming language is a foundational technology for modern computing with billions of lines of code implementing everything from hobby projects to commercial operating-systems.
    213217This installation base and the programmers producing it represent a massive software-engineering investment spanning decades and likely to continue for decades more.
    214218Even with all its problems, C continues to be popular because it allows writing software at virtually any level in a computer system without restriction.
    215 For system programming, where direct access to hardware, storage management, and real-time issues are a requirement, C is usually the only language of choice.
    216 The TIOBE index~\cite{TIOBE} for February 2020 ranks the top six most \emph{popular} programming languages as \Index*{Java} 17.4\%, C 16.8\%, Python 9.3\%, \Index*[C++]{\CC{}} 6.2\%, \Csharp 5.9\%, Visual Basic 5.9\% = 61.5\%, where the next 50 languages are less than 2\% each, with a long tail.
     219For system programming, where direct access to hardware, storage management, and real-time issues are a requirement, C is the only language of choice.
     220The TIOBE index~\cite{TIOBE} for February 2021 ranks the top six most \emph{popular} programming languages as C 17.4\%, \Index*{Java} 12\%, Python 12\%, \Index*[C++]{\CC{}} 7.6\%, \Csharp 4\%, Visual Basic 3.8\% = 56.8\%, where the next 50 languages are less than 2\% each, with a long tail.
    217221The top 4 rankings over the past 35 years are:
    218222\begin{center}
    219223\setlength{\tabcolsep}{10pt}
    220224\begin{tabular}{@{}rcccccccc@{}}
    221                 & 2020  & 2015  & 2010  & 2005  & 2000  & 1995  & 1990  & 1985  \\ \hline
    222 Java    & 1             & 2             & 1             & 2             & 3             & -             & -             & -             \\
    223 \R{C}   & \R{2} & \R{1} & \R{2} & \R{1} & \R{1} & \R{2} & \R{1} & \R{1} \\
    224 Python  & 3             & 7             & 6             & 6             & 22    & 21    & -             & -             \\
    225 \CC             & 4             & 4             & 4             & 3             & 2             & 1             & 2             & 12    \\
     225                & 2021  & 2016  & 2011  & 2006  & 2001  & 1996  & 1991  & 1986  \\ \hline
     226\R{C}   & \R{1} & \R{2} & \R{2} & \R{1} & \R{1} & \R{1} & \R{1} & \R{1} \\
     227Java    & 2             & 1             & 1             & 2             & 3             & 28    & -             & -             \\
     228Python  & 3             & 5             & 6             & 7             & 23    & 13    & -             & -             \\
     229\CC             & 4             & 3             & 3             & 3             & 2             & 2             & 2             & 8             \\
    226230\end{tabular}
    227231\end{center}
     
    232236As stated, the goal of the \CFA project is to engineer modern language-features into C in an evolutionary rather than revolutionary way.
    233237\CC~\cite{C++14,C++} is an example of a similar project;
    234 however, it largely extended the C language, and did not address most of C's existing problems.\footnote{%
     238however, it largely extended the C language, and did not address many of C's existing problems.\footnote{%
    235239Two important existing problems addressed were changing the type of character literals from ©int© to ©char© and enumerator from ©int© to the type of its enumerators.}
    236240\Index*{Fortran}~\cite{Fortran08}, \Index*{Ada}~\cite{Ada12}, and \Index*{Cobol}~\cite{Cobol14} are examples of programming languages that took an evolutionary approach, where modern language-features (\eg objects, concurrency) are added and problems fixed within the framework of the existing language.
     
    241245
    242246The result of this project is a language that is largely backwards compatible with \Index*[C11]{\Celeven{}}~\cite{C11}, but fixes many of the well known C problems while adding modern language-features.
    243 To achieve these goals required a significant engineering exercise, where we had to ``think inside the existing C box''.
    244 Without these significant extension to C, it is unable to cope with the needs of modern programming problems and programmers;
    245 as a result, it will fade into disuse.
    246 Considering the large body of existing C code and programmers, there is significant impetus to ensure C is transformed into a modern programming language.
     247To achieve these goals required a significant engineering exercise, \ie ``thinking \emph{inside} the C box''.
     248Considering the large body of existing C code and programmers, there is significant impetus to ensure C is transformed into a modern language.
    247249While \Index*[C11]{\Celeven{}} made a few simple extensions to the language, nothing was added to address existing problems in the language or to augment the language with modern language-features.
    248250While some may argue that modern language-features may make C complex and inefficient, it is clear a language without modern capabilities is insufficient for the advanced programming problems existing today.
     
    251253\section{History}
    252254
    253 The \CFA project started with \Index*{Dave Till}\index{Till, Dave}'s \Index*{K-W C}~\cite{Buhr94a,Till89}, which extended C with new declaration syntax, multiple return values from routines, and advanced assignment capabilities using the notion of tuples.
    254 (See~\cite{Werther96} for similar work in \Index*[C++]{\CC{}}.)
     255The \CFA project started with \Index*{Dave Till}\index{Till, Dave}'s \Index*{K-W C}~\cite{Buhr94a,Till89}, which extended C with new declaration syntax, multiple return values from routines, and advanced assignment capabilities using the notion of tuples \see{\cite{Werther96} for similar work in \Index*[C++]{\CC{}}}.
    255256The first \CFA implementation of these extensions was by \Index*{Rodolfo Esteves}\index{Esteves, Rodolfo}~\cite{Esteves04}.
    256257
    257258The signature feature of \CFA is \emph{\Index{overload}able} \Index{parametric-polymorphic} functions~\cite{forceone:impl,Cormack90,Duggan96} with functions generalized using a ©forall© clause (giving the language its name):
    258259\begin{cfa}
    259 ®forall( otype T )® T identity( T val ) { return val; }
    260 int forty_two = identity( 42 ); §\C{// T is bound to int, forty\_two == 42}§
     260@forall( otype T )@ T identity( T val ) { return val; }
     261int forty_two = identity( 42 ); $\C{// T is bound to int, forty\_two == 42}$
    261262\end{cfa}
    262263% extending the C type system with parametric polymorphism and overloading, as opposed to the \Index*[C++]{\CC{}} approach of object-oriented extensions.
    263264\CFA{}\hspace{1pt}'s polymorphism was originally formalized by \Index*{Glen Ditchfield}\index{Ditchfield, Glen}~\cite{Ditchfield92}, and first implemented by \Index*{Richard Bilson}\index{Bilson, Richard}~\cite{Bilson03}.
    264265However, at that time, there was little interesting in extending C, so work did not continue.
    265 As the saying goes, ``\Index*{What goes around, comes around.}'', and there is now renewed interest in the C programming language because of legacy code-bases, so the \CFA project has been restarted.
     266As the saying goes, ``\Index*{What goes around, comes around.}'', and there is now renewed interest in the C programming language because of the legacy code-base, so the \CFA project was restarted in 2015.
    266267
    267268
     
    273274This feature allows \CFA programmers to take advantage of the existing panoply of C libraries to access thousands of external software features.
    274275Language developers often state that adequate \Index{library support} takes more work than designing and implementing the language itself.
    275 Fortunately, \CFA, like \Index*[C++]{\CC{}}, starts with immediate access to all exiting C libraries, and in many cases, can easily wrap library routines with simpler and safer interfaces, at very low cost.
     276Fortunately, \CFA, like \Index*[C++]{\CC{}}, starts with immediate access to all exiting C libraries, and in many cases, can easily wrap library routines with simpler and safer interfaces, at zero or very low cost.
    276277Hence, \CFA begins by leveraging the large repository of C libraries, and than allows programmers to incrementally augment their C programs with modern \Index{backward-compatible} features.
    277278
     
    286287
    287288double key = 5.0, vals[10] = { /* 10 sorted floating values */ };
    288 double * val = (double *)bsearch( &key, vals, 10, sizeof(vals[0]), comp ); §\C{// search sorted array}§
     289double * val = (double *)bsearch( &key, vals, 10, sizeof(vals[0]), comp ); $\C{// search sorted array}$
    289290\end{cfa}
    290291which can be augmented simply with a polymorphic, type-safe, \CFA-overloaded wrappers:
     
    295296
    296297forall( otype T | { int ?<?( T, T ); } ) unsigned int bsearch( T key, const T * arr, size_t size ) {
    297         T * result = bsearch( key, arr, size ); §\C{// call first version}§
    298         return result ? result - arr : size; } §\C{// pointer subtraction includes sizeof(T)}§
    299 
    300 double * val = bsearch( 5.0, vals, 10 ); §\C{// selection based on return type}§
     298        T * result = bsearch( key, arr, size ); $\C{// call first version}$
     299        return result ? result - arr : size; } $\C{// pointer subtraction includes sizeof(T)}$
     300
     301double * val = bsearch( 5.0, vals, 10 ); $\C{// selection based on return type}$
    301302int posn = bsearch( 5.0, vals, 10 );
    302303\end{cfa}
     
    310311\begin{cfa}
    311312forall( dtype T | sized(T) ) T * malloc( void ) { return (T *)malloc( sizeof(T) ); }
    312 int * ip = malloc(); §\C{// select type and size from left-hand side}§
     313int * ip = malloc(); $\C{// select type and size from left-hand side}$
    313314double * dp = malloc();
    314315struct S {...} * sp = malloc();
     
    319320However, it is necessary to differentiate between C and \CFA code because of name \Index{overload}ing, as for \CC.
    320321For example, the C math-library provides the following routines for computing the absolute value of the basic types: ©abs©, ©labs©, ©llabs©, ©fabs©, ©fabsf©, ©fabsl©, ©cabsf©, ©cabs©, and ©cabsl©.
    321 Whereas, \CFA wraps each of these routines into ones with the overloaded name ©abs©:
    322 \begin{cfa}
    323 char ®abs®( char );
    324 extern "C" { int ®abs®( int ); } §\C{// use default C routine for int}§
    325 long int ®abs®( long int );
    326 long long int ®abs®( long long int );
    327 float ®abs®( float );
    328 double ®abs®( double );
    329 long double ®abs®( long double );
    330 float _Complex ®abs®( float _Complex );
    331 double _Complex ®abs®( double _Complex );
    332 long double _Complex ®abs®( long double _Complex );
    333 \end{cfa}
    334 The problem is the name clash between the library routine ©abs© and the \CFA names ©abs©.
    335 Hence, names appearing in an ©extern "C"© block have \newterm*{C linkage}.
    336 Then overloading polymorphism uses a mechanism called \newterm{name mangling}\index{mangling!name} to create unique names that are different from C names, which are not mangled.
    337 Hence, there is the same need, as in \CC, to know if a name is a C or \CFA name, so it can be correctly formed.
    338 There is no way around this problem, other than C's approach of creating unique names for each pairing of operation and types.
    339 
    340 This example strongly illustrates a core idea in \CFA: \emph{the \Index{power of a name}}.
     322Whereas, \CFA wraps each of these routines into one overloaded name ©abs©:
     323\begin{cfa}
     324char @abs@( char );
     325extern "C" { int @abs@( int ); } $\C{// use default C routine for int}$
     326long int @abs@( long int );
     327long long int @abs@( long long int );
     328float @abs@( float );
     329double @abs@( double );
     330long double @abs@( long double );
     331float _Complex @abs@( float _Complex );
     332double _Complex @abs@( double _Complex );
     333long double _Complex @abs@( long double _Complex );
     334\end{cfa}
     335The problem is \Index{name clash} between the C name ©abs© and the \CFA names ©abs©, resulting in two name linkages\index{C linkage}: ©extern "C"© and ©extern "Cforall"© (default).
     336Overloaded names must use \newterm{name mangling}\index{mangling!name} to create unique names that are different from unmangled C names.
     337Hence, there is the same need as in \CC to know if a name is a C or \CFA name, so it can be correctly formed.
     338The only way around this problem is C's approach of creating unique names for each pairing of operation and type.
     339
     340This example illustrates a core idea in \CFA: \emph{the \Index{power of a name}}.
    341341The name ``©abs©'' evokes the notion of absolute value, and many mathematical types provide the notion of absolute value.
    342342Hence, knowing the name ©abs© is sufficient to apply it to any type where it is applicable.
     
    344344
    345345
    346 \section[Compiling a CFA Program]{Compiling a \CFA Program}
     346\section{\CFA Compilation}
    347347
    348348The command ©cfa© is used to compile a \CFA program and is based on the \Index{GNU} \Indexc{gcc} command, \eg:
    349349\begin{cfa}
    350 cfa§\indexc{cfa}\index{compilation!cfa@©cfa©}§ [ gcc-options ] [ C/§\CFA{}§ source-files ] [ assembler/loader files ]
    351 \end{cfa}
    352 \CFA programs having the following ©gcc© flags turned on:
    353 \begin{description}
     350cfa$\indexc{cfa}\index{compilation!cfa@©cfa©}$ [ gcc/$\CFA{}$-options ] [ C/$\CFA{}$ source-files ] [ assembler/loader files ]
     351\end{cfa}
     352There is no ordering among options (flags) and files, unless an option has an argument, which must appear immediately after the option possibly with or without a space separating option and argument.
     353
     354\CFA has the following ©gcc© flags turned on:
     355\begin{description}[topsep=0pt]
    354356\item
    355357\Indexc{-std=gnu11}\index{compilation option!-std=gnu11@{©-std=gnu11©}}
     
    359361Use the traditional GNU semantics for inline routines in C11 mode, which allows inline routines in header files.
    360362\end{description}
    361 The following new \CFA options are available:
    362 \begin{description}
     363
     364\CFA has the following new options:
     365\begin{description}[topsep=0pt]
    363366\item
    364367\Indexc{-CFA}\index{compilation option!-CFA@©-CFA©}
    365 Only the C preprocessor and the \CFA translator steps are performed and the transformed program is written to standard output, which makes it possible to examine the code generated by the \CFA translator.
     368Only the C preprocessor (flag ©-E©) and the \CFA translator steps are performed and the transformed program is written to standard output, which makes it possible to examine the code generated by the \CFA translator.
    366369The generated code starts with the standard \CFA \Index{prelude}.
     370
     371\item
     372\Indexc{-XCFA}\index{compilation option!-XCFA@©-XCFA©}
     373Pass next flag as-is to the ©cfa-cpp© translator (see details below).
    367374
    368375\item
    369376\Indexc{-debug}\index{compilation option!-debug@©-debug©}
    370377The program is linked with the debugging version of the runtime system.
    371 The debug version performs runtime checks to help during the debugging phase of a \CFA program, but can substantially slow program execution.
     378The debug version performs runtime checks to aid the debugging phase of a \CFA program, but can substantially slow program execution.
    372379The runtime checks should only be removed after the program is completely debugged.
    373380\textbf{This option is the default.}
     
    399406\item
    400407\Indexc{-no-include-stdhdr}\index{compilation option!-no-include-stdhdr@©-no-include-stdhdr©}
    401 Do not supply ©extern "C"© wrappers for \Celeven standard include files (see~\VRef{s:StandardHeaders}).
     408Do not supply ©extern "C"© wrappers for \Celeven standard include files \see{\VRef{s:StandardHeaders}}.
    402409\textbf{This option is \emph{not} the default.}
    403410\end{comment}
     
    430437\begin{cfa}
    431438#ifndef __CFORALL__
    432 #include <stdio.h>§\indexc{stdio.h}§ §\C{// C header file}§
     439#include <stdio.h>$\indexc{stdio.h}$ $\C{// C header file}$
    433440#else
    434 #include <fstream>§\indexc{fstream}§ §\C{// \CFA header file}§
     441#include <fstream>$\indexc{fstream}$ $\C{// \CFA header file}$
    435442#endif
    436443\end{cfa}
     
    438445
    439446The \CFA translator has multiple steps.
    440 The following flags control how the tranlator works, the stages run, and printing within a stage.
     447The following flags control how the translator works, the stages run, and printing within a stage.
    441448The majority of these flags are used by \CFA developers, but some are occasionally useful to programmers.
     449Each option must be escaped with \Indexc{-XCFA}\index{translator option!-XCFA@{©-XCFA©}} to direct it to the compiler step, similar to the ©-Xlinker© flag for the linker, \eg:
     450\begin{lstlisting}[language=sh]
     451cfa $test$.cfa -CFA -XCFA -p # print translated code without printing the standard prelude
     452cfa $test$.cfa -XCFA -P -XCFA parse -XCFA -n # show program parse without prelude
     453\end{lstlisting}
    442454\begin{description}[topsep=5pt,itemsep=0pt,parsep=0pt]
    443455\item
    444 \Indexc{-h}\index{translator option!-h@{©-h©}}, \Indexc{--help}\index{translator option!--help@{©--help©}} \, print help message
    445 \item
    446 \Indexc{-l}\index{translator option!-l@{©-l©}}, \Indexc{--libcfa}\index{translator option!--libcfa@{©--libcfa©}} \, generate libcfa.c
     456\Indexc{-c}\index{translator option!-c@{©-c©}}, \Indexc{--colors}\index{translator option!--colors@{©--colors©}} \, diagnostic color: ©never©, ©always©, \lstinline[deletekeywords=auto]{auto}
     457\item
     458\Indexc{-g}\index{translator option!-g@{©-g©}}, \Indexc{--gdb}\index{translator option!--gdb@{©--gdb©}} \, wait for gdb to attach
     459\item
     460\Indexc{-h}\index{translator option!-h@{©-h©}}, \Indexc{--help}\index{translator option!--help@{©--help©}} \, print translator help message
     461\item
     462\Indexc{-l}\index{translator option!-l@{©-l©}}, \Indexc{--libcfa}\index{translator option!--libcfa@{©--libcfa©}} \, generate ©libcfa.c©
    447463\item
    448464\Indexc{-L}\index{translator option!-L@{©-L©}}, \Indexc{--linemarks}\index{translator option!--linemarks@{©--linemarks©}} \, generate line marks
     
    454470\Indexc{-n}\index{translator option!-n@{©-n©}}, \Indexc{--no-prelude}\index{translator option!--no-prelude@{©--no-prelude©}} \, do not read prelude
    455471\item
    456 \Indexc{-p}\index{translator option!-p@{©-p©}}, \Indexc{--prototypes}\index{translator option!--prototypes@{©--prototypes©}} \, generate prototypes for prelude functions
     472\Indexc{-p}\index{translator option!-p@{©-p©}}, \Indexc{--prototypes}\index{translator option!--prototypes@{©--prototypes©}} \, do not generate prelude prototypes $\Rightarrow$ prelude not printed
     473\item
     474\Indexc{-d}\index{translator option!-d@{©-d©}}, \Indexc{--deterministic-out}\index{translator option!--deterministic-out@{©--deterministic-out©}} \, only print deterministic output
    457475\item
    458476\Indexc{-P}\index{translator option!-P@{©-P©}}, \Indexc{--print}\index{translator option!--print@{©--print©}} \, one of:
    459477\begin{description}[topsep=0pt,itemsep=0pt,parsep=0pt]
    460478\item
     479\Indexc{ascodegen}\index{translator option!-P@{©-P©}!©ascodegen©}\index{translator option!--print@{©-print©}!©ascodegen©} \, as codegen rather than AST
     480\item
     481\Indexc{asterr}\index{translator option!-P@{©-P©}!©asterr©}\index{translator option!--print@{©-print©}!©asterr©} \, AST on error
     482\item
     483\Indexc{declstats}\index{translator option!-P@{©-P©}!©declstats©}\index{translator option!--print@{©-print©}!©declstats©} \, code property statistics
     484\item
     485\Indexc{parse}\index{translator option!-P@{©-P©}!©parse©}\index{translator option!--print@{©-print©}!©parse©} \, yacc (parsing) debug information
     486\item
     487\Indexc{pretty}\index{translator option!-P@{©-P©}!©pretty©}\index{translator option!--print@{©-print©}!©pretty©} \, prettyprint for ©ascodegen© flag
     488\item
     489\Indexc{rproto}\index{translator option!-P@{©-P©}!©rproto©}\index{translator option!--print@{©-print©}!©rproto©} \, resolver-proto instance
     490\item
     491\Indexc{rsteps}\index{translator option!-P@{©-P©}!©rsteps©}\index{translator option!--print@{©-print©}!©rsteps©} \, resolver steps
     492\item
     493\Indexc{tree}\index{translator option!-P@{©-P©}!©tree©}\index{translator option!--print@{©-print©}!©tree©} \, parse tree
     494\item
     495\Indexc{ast}\index{translator option!-P@{©-P©}!©ast©}\index{translator option!--print@{©-print©}!©ast©} \, AST after parsing
     496\item
     497\Indexc{symevt}\index{translator option!-P@{©-P©}!©symevt©}\index{translator option!--print@{©-print©}!©symevt©} \, symbol table events
     498\item
    461499\Indexc{altexpr}\index{translator option!-P@{©-P©}!©altexpr©}\index{translator option!--print@{©-print©}!©altexpr©} \, alternatives for expressions
    462500\item
    463 \Indexc{ascodegen}\index{translator option!-P@{©-P©}!©ascodegen©}\index{translator option!--print@{©-print©}!©ascodegen©} \, as codegen rather than AST
    464 \item
    465 \Indexc{ast}\index{translator option!-P@{©-P©}!©ast©}\index{translator option!--print@{©-print©}!©ast©} \, AST after parsing
    466 \item
    467501\Indexc{astdecl}\index{translator option!-P@{©-P©}!©astdecl©}\index{translator option!--print@{©-print©}!©astdecl©} \, AST after declaration validation pass
    468502\item
    469 \Indexc{asterr}\index{translator option!-P@{©-P©}!©asterr©}\index{translator option!--print@{©-print©}!©asterr©} \, AST on error
     503\Indexc{resolver}\index{translator option!-P@{©-P©}!©resolver©}\index{translator option!--print@{©-print©}!©resolver©} \, before resolver step
    470504\item
    471505\Indexc{astexpr}\index{translator option!-P@{©-P©}!©astexpr©}\index{translator option!--print@{©-print©}!©altexpr©} \, AST after expression analysis
    472506\item
     507\Indexc{ctordtor}\index{translator option!-P@{©-P©}!©ctordtor©}\index{translator option!--print@{©-print©}!©ctordtor©} \, after ctor/dtor are replaced
     508\item
     509\Indexc{tuple}\index{translator option!-P@{©-P©}!©tuple©}\index{translator option!--print@{©-print©}!©tuple©} \, after tuple expansion
     510\item
    473511\Indexc{astgen}\index{translator option!-P@{©-P©}!©astgen©}\index{translator option!--print@{©-print©}!©astgen©} \, AST after instantiate generics
    474512\item
    475513\Indexc{box}\index{translator option!-P@{©-P©}!©box©}\index{translator option!--print@{©-print©}!©box©} \, before box step
    476514\item
    477 \Indexc{ctordtor}\index{translator option!-P@{©-P©}!©ctordtor©}\index{translator option!--print@{©-print©}!©ctordtor©} \, after ctor/dtor are replaced
    478 \item
    479515\Indexc{codegen}\index{translator option!-P@{©-P©}!©codegen©}\index{translator option!--print@{©-print©}!©codegen©} \, before code generation
    480 \item
    481 \Indexc{declstats}\index{translator option!-P@{©-P©}!©declstats©}\index{translator option!--print@{©-print©}!©declstats©} \, code property statistics
    482 \item
    483 \Indexc{parse}\index{translator option!-P@{©-P©}!©parse©}\index{translator option!--print@{©-print©}!©parse©} \, yacc (parsing) debug information
    484 \item
    485 \Indexc{pretty}\index{translator option!-P@{©-P©}!©pretty©}\index{translator option!--print@{©-print©}!©pretty©} \, prettyprint for ascodegen flag
    486 \item
    487 \Indexc{resolver}\index{translator option!-P@{©-P©}!©resolver©}\index{translator option!--print@{©-print©}!©resolver©} \, before resolver step
    488 \item
    489 \Indexc{rproto}\index{translator option!-P@{©-P©}!©rproto©}\index{translator option!--print@{©-print©}!©rproto©} \, resolver-proto instance
    490 \item
    491 \Indexc{rsteps}\index{translator option!-P@{©-P©}!©rsteps©}\index{translator option!--print@{©-print©}!©rsteps©} \, resolver steps
    492 \item
    493 \Indexc{symevt}\index{translator option!-P@{©-P©}!©symevt©}\index{translator option!--print@{©-print©}!©symevt©} \, symbol table events
    494 \item
    495 \Indexc{tree}\index{translator option!-P@{©-P©}!©tree©}\index{translator option!--print@{©-print©}!©tree©} \, parse tree
    496 \item
    497 \Indexc{tuple}\index{translator option!-P@{©-P©}!©tuple©}\index{translator option!--print@{©-print©}!©tuple©} \, after tuple expansion
    498516\end{description}
    499517\item
    500518\Indexc{--prelude-dir} <directory> \, prelude directory for debug/nodebug
    501519\item
    502 \Indexc{-S}\index{translator option!-S@{©-S©}!©counters,heap,time,all,none©}, \Indexc{--statistics}\index{translator option!--statistics@{©--statistics©}!©counters,heap,time,all,none©} <option-list> \, enable profiling information:
    503 \begin{description}[topsep=0pt,itemsep=0pt,parsep=0pt]
    504 \item
    505 \Indexc{counters,heap,time,all,none}
    506 \end{description}
     520\Indexc{-S}\index{translator option!-S@{©-S©}!©counters,heap,time,all,none©}, \Indexc{--statistics}\index{translator option!--statistics@{©--statistics©}!©counters,heap,time,all,none©} <option-list> \, enable profiling information: ©counters©, ©heap©, ©time©, ©all©, ©none©
    507521\item
    508522\Indexc{-t}\index{translator option!-t@{©-t©}}, \Indexc{--tree}\index{translator option!--tree@{©--tree©}} build in tree
     
    513527\label{s:BackquoteIdentifiers}
    514528
    515 \CFA introduces several new keywords (see \VRef{s:CFAKeywords}) that can clash with existing C variable-names in legacy code.
     529\CFA introduces several new keywords \see{\VRef{s:CFAKeywords}} that can clash with existing C variable-names in legacy code.
    516530Keyword clashes are accommodated by syntactic transformations using the \CFA backquote escape-mechanism:
    517531\begin{cfa}
    518 int ®``®otype = 3; §\C{// make keyword an identifier}§
    519 double ®``®forall = 3.5;
     532int @``@otype = 3; $\C{// make keyword an identifier}$
     533double @``@forall = 3.5;
    520534\end{cfa}
    521535
    522536Existing C programs with keyword clashes can be converted by enclosing keyword identifiers in backquotes, and eventually the identifier name can be changed to a non-keyword name.
    523 \VRef[Figure]{f:HeaderFileInterposition} shows how clashes in existing C header-files (see~\VRef{s:StandardHeaders}) can be handled using preprocessor \newterm{interposition}: ©#include_next© and ©-I filename©.
     537\VRef[Figure]{f:HeaderFileInterposition} shows how clashes in existing C header-files \see{\VRef{s:StandardHeaders}} can be handled using preprocessor \newterm{interposition}: ©#include_next© and ©-I filename©.
    524538Several common C header-files with keyword clashes are fixed in the standard \CFA header-library, so there is a seamless programming-experience.
    525539
     
    527541\begin{cfa}
    528542// include file uses the CFA keyword "with".
    529 #if ! defined( with ) §\C{// nesting ?}§
    530 #define with ®``®with §\C{// make keyword an identifier}§
     543#if ! defined( with )                                                   $\C{// nesting ?}$
     544#define with @``@with                                                   $\C{// make keyword an identifier}$
    531545#define __CFA_BFD_H__
    532546#endif
    533 §{\color{red}\#\textbf{include\_next} <bfdlink.h>}§ §\C{// must have internal check for multiple expansion}§
    534 #if defined( with ) && defined( __CFA_BFD_H__ ) §\C{// reset only if set}§
     547$\R{\#include\_next} <bfdlink.h>$                               $\C{// must have internal check for multiple expansion}$
     548#if defined( with ) && defined( __CFA_BFD_H__ ) $\C{// reset only if set}$
    535549#undef with
    536550#undef __CFA_BFD_H__
     
    544558\section{Constant Underscores}
    545559
    546 Numeric constants are extended to allow \Index{underscore}s\index{constant!underscore}, \eg:
    547 \begin{cfa}
    548 2®_®147®_®483®_®648; §\C{// decimal constant}§
    549 56®_®ul; §\C{// decimal unsigned long constant}§
    550 0®_®377; §\C{// octal constant}§
    551 0x®_®ff®_®ff; §\C{// hexadecimal constant}§
    552 0x®_®ef3d®_®aa5c; §\C{// hexadecimal constant}§
    553 3.141®_®592®_®654; §\C{// floating constant}§
    554 10®_®e®_®+1®_®00; §\C{// floating constant}§
    555 0x®_®ff®_®ff®_®p®_®3; §\C{// hexadecimal floating}§
    556 0x®_®1.ffff®_®ffff®_®p®_®128®_®l; §\C{// hexadecimal floating long constant}§
    557 L®_®§"\texttt{\textbackslash{x}}§®_®§\texttt{ff}§®_®§\texttt{ee}"§; §\C{// wide character constant}§
     560Numeric constants are extended to allow \Index{underscore}s\index{constant!underscore} as a separator, \eg:
     561\begin{cfa}
     5622@_@147@_@483@_@648; $\C{// decimal constant}$
     56356@_@ul; $\C{// decimal unsigned long constant}$
     5640@_@377; $\C{// octal constant}$
     5650x@_@ff@_@ff; $\C{// hexadecimal constant}$
     5660x@_@ef3d@_@aa5c; $\C{// hexadecimal constant}$
     5673.141@_@592@_@654; $\C{// floating constant}$
     56810@_@e@_@+1@_@00; $\C{// floating constant}$
     5690x@_@ff@_@ff@_@p@_@3; $\C{// hexadecimal floating}$
     5700x@_@1.ffff@_@ffff@_@p@_@128@_@l; $\C{// hexadecimal floating long constant}$
     571L@_@$"\texttt{\textbackslash{x}}$@_@$\texttt{ff}$@_@$\texttt{ee}"$; $\C{// wide character constant}$
    558572\end{cfa}
    559573The rules for placement of underscores are:
     
    574588It is significantly easier to read and enter long constants when they are broken up into smaller groupings (many cultures use comma and/or period among digits for the same purpose).
    575589This extension is backwards compatible, matches with the use of underscore in variable names, and appears in \Index*{Ada} and \Index*{Java} 8.
     590\CC uses the single quote (©'©) as a separator, restricted within a sequence of digits, \eg ©0xaa©©'©©ff©, ©3.141©©'©©592E1©©'©©1©.
    576591
    577592
    578593\section{Exponentiation Operator}
    579594
    580 C, \CC, and Java (and many other programming languages) have no exponentiation operator\index{exponentiation!operator}\index{operator!exponentiation}, \ie $x^y$, and instead use a routine, like \Indexc{pow(x,y)}, to perform the exponentiation operation.
    581 \CFA extends the basic operators with the exponentiation operator ©?®\®?©\index{?\\?@©?®\®?©} and ©?\=?©\index{?\\=?@©®\®=?©}, as in, ©x ®\® y© and ©x ®\®= y©, which means $x^y$ and $x \leftarrow x^y$.
    582 The priority of the exponentiation operator is between the cast and multiplicative operators, so that ©w * (int)x \ (int)y * z© is parenthesized as ©((w * (((int)x) \ ((int)y))) * z)©.
     595C, \CC, and Java (and other programming languages) have no exponentiation operator\index{exponentiation!operator}\index{operator!exponentiation}, \ie $x^y$, and instead use a routine, like \Indexc{pow(x,y)}, to perform the exponentiation operation.
     596\CFA extends the basic operators with the exponentiation operator ©?©\R{©\\©}©?©\index{?\\?@©?@\@?©} and ©?©\R{©\\©}©=?©\index{?\\=?@©@\@=?©}, as in, ©x ©\R{©\\©}© y© and ©x ©\R{©\\©}©= y©, which means $x^y$ and $x \leftarrow x^y$.
     597The priority of the exponentiation operator is between the cast and multiplicative operators, so that ©w * (int)x \ (int)y * z© is parenthesized as ©(w * (((int)x) \ ((int)y))) * z©.
    583598
    584599There are exponentiation operators for integral and floating types, including the builtin \Index{complex} types.
     
    587602Floating exponentiation\index{exponentiation!floating} is performed using \Index{logarithm}s\index{exponentiation!logarithm}, so the exponent cannot be negative.
    588603\begin{cfa}
    589 sout | 1 ®\® 0 | 1 ®\® 1 | 2 ®\® 8 | -4 ®\® 3 | 5 ®\® 3 | 5 ®\® 32 | 5L ®\® 32 | 5L ®\® 64 | -4 ®\® -3 | -4.0 ®\® -3 | 4.0 ®\® 2.1
    590            | (1.0f+2.0fi) ®\® (3.0f+2.0fi);
    591 1 1 256 -64 125 ®0® 3273344365508751233 ®0® ®0® -0.015625 18.3791736799526 0.264715-1.1922i
     604sout | 1 @\@ 0 | 1 @\@ 1 | 2 @\@ 8 | -4 @\@ 3 | 5 @\@ 3 | 5 @\@ 32 | 5L @\@ 32 | 5L @\@ 64 | -4 @\@ -3 | -4.0 @\@ -3 | 4.0 @\@ 2.1
     605           | (1.0f+2.0fi) @\@ (3.0f+2.0fi);
     6061 1 256 -64 125 @0@ 3273344365508751233 @0@ @0@ -0.015625 18.3791736799526 0.264715-1.1922i
    592607\end{cfa}
    593608Note, ©5 \ 32© and ©5L \ 64© overflow, and ©-4 \ -3© is a fraction but stored in an integer so all three computations generate an integral zero.
    594 Parenthesis are necessary for complex constants or the expression is parsed as ©1.0f+®(®2.0fi \ 3.0f®)®+2.0fi©.
     609Because exponentiation has higher priority than ©+©, parenthesis are necessary for exponentiation of \Index{complex constant}s or the expression is parsed as ©1.0f+©\R{©(©}©2.0fi \ 3.0f©\R{©)©}©+2.0fi©, requiring \R{©(©}©1.0f+2.0fi©\R{©)©}© \ ©\R{©(©}©3.0f+2.0fi©\R{©)©}.
     610
    595611The exponentiation operator is available for all the basic types, but for user-defined types, only the integral-computation version is available.
    596612\begin{cfa}
    597 forall( otype OT | { void ?{}( OT & this, one_t ); OT ?*?( OT, OT ); } )
    598 OT ?®\®?( OT ep, unsigned int y );
    599 forall( otype OT | { void ?{}( OT & this, one_t ); OT ?*?( OT, OT ); } )
    600 OT ?®\®?( OT ep, unsigned long int y );
     613forall( otype T | { void ?{}( T & this, one_t ); T ?*?( T, T ); } )
     614T ?@\@?( T ep, unsigned int y );
     615forall( otype T | { void ?{}( T & this, one_t ); T ?*?( T, T ); } )
     616T ?@\@?( T ep, unsigned long int y );
    601617\end{cfa}
    602618The user type ©T© must define multiplication, one (©1©), and ©*©.
     
    609625
    610626%\subsection{\texorpdfstring{\protect\lstinline@if@/\protect\lstinline@while@ Statement}{if Statement}}
    611 \subsection{\texorpdfstring{\LstKeywordStyle{if}/\LstKeywordStyle{while} Statement}{if/while Statement}}
    612 
    613 The ©if©/©while© expression allows declarations, similar to ©for© declaration expression.
    614 (Does not make sense for ©do©-©while©.)
    615 \begin{cfa}
    616 if ( ®int x = f()® ) ... §\C{// x != 0}§
    617 if ( ®int x = f(), y = g()® ) ... §\C{// x != 0 \&\& y != 0}§
    618 if ( ®int x = f(), y = g(); x < y® ) ... §\C{// relational expression}§
    619 if ( ®struct S { int i; } x = { f() }; x.i < 4® ) §\C{// relational expression}§
    620 
    621 while ( ®int x = f()® ) ... §\C{// x != 0}§
    622 while ( ®int x = f(), y = g()® ) ... §\C{// x != 0 \&\& y != 0}§
    623 while ( ®int x = f(), y = g(); x < y® ) ... §\C{// relational expression}§
    624 while ( ®struct S { int i; } x = { f() }; x.i < 4® ) ... §\C{// relational expression}§
    625 \end{cfa}
    626 Unless a relational expression is specified, each variable is compared not equal to 0, which is the standard semantics for the ©if©/©while© expression, and the results are combined using the logical ©&&© operator.\footnote{\CC only provides a single declaration always compared not equal to 0.}
    627 The scope of the declaration(s) is local to the @if@ statement but exist within both the ``then'' and ``else'' clauses.
     627\subsection{\texorpdfstring{\LstKeywordStyle{if} / \LstKeywordStyle{while} Statement}{if / while Statement}}
     628
     629The ©if©/©while© expression allows declarations, similar to ©for© declaration expression.\footnote{
     630Declarations in the ©do©-©while© condition are not useful because they appear after the loop body.}
     631\begin{cfa}
     632if ( @int x = f()@ ) ... $\C{// x != 0}$
     633if ( @int x = f(), y = g()@ ) ... $\C{// x != 0 \&\& y != 0}$
     634if ( @int x = f(), y = g(); x < y@ ) ... $\C{// relational expression}$
     635if ( @struct S { int i; } x = { f() }; x.i < 4@ ) $\C{// relational expression}$
     636
     637while ( @int x = f()@ ) ... $\C{// x != 0}$
     638while ( @int x = f(), y = g()@ ) ... $\C{// x != 0 \&\& y != 0}$
     639while ( @int x = f(), y = g(); x < y@ ) ... $\C{// relational expression}$
     640while ( @struct S { int i; } x = { f() }; x.i < 4@ ) ... $\C{// relational expression}$
     641\end{cfa}
     642Unless a relational expression is specified, each variable is compared not equal to 0, which is the standard semantics for the ©if©/©while© expression, and the results are combined using the logical ©&&© operator.
     643The scope of the declaration(s) is local to the ©if© statement but exist within both the \emph{then} and \emph{else} clauses.
     644\CC only provides a single declaration always compared ©!=© to 0.
    628645
    629646
    630647%\section{\texorpdfstring{\protect\lstinline@case@ Clause}{case Clause}}
    631648\subsection{\texorpdfstring{\LstKeywordStyle{case} Clause}{case Clause}}
     649\label{s:caseClause}
    632650
    633651C restricts the ©case© clause of a ©switch© statement to a single value.
     
    640658\begin{cfa}
    641659switch ( i ) {
    642   case ®1, 3, 5®:
     660  case @1, 3, 5@:
    643661        ...
    644   case ®2, 4, 6®:
     662  case @2, 4, 6@:
    645663        ...
    646664}
     
    670688\begin{cfa}
    671689switch ( i ) {
    672   case ®1~5:® §\C{// 1, 2, 3, 4, 5}§
     690  case @1~5:@ $\C{// 1, 2, 3, 4, 5}$
    673691        ...
    674   case ®10~15:® §\C{// 10, 11, 12, 13, 14, 15}§
     692  case @10~15:@ $\C{// 10, 11, 12, 13, 14, 15}$
    675693        ...
    676694}
     
    678696Lists of subranges are also allowed.
    679697\begin{cfa}
    680 case ®1~5, 12~21, 35~42®:
     698case @1~5, 12~21, 35~42@:
    681699\end{cfa}
    682700
     
    722740if ( argc == 3 ) {
    723741        // open output file
    724         ®// open input file
    725 ®} else if ( argc == 2 ) {
    726         ®// open input file (duplicate)
    727 
    728 ®} else {
     742        @// open input file
     743@} else if ( argc == 2 ) {
     744        @// open input file (duplicate)
     745
     746@} else {
    729747        // usage message
    730748}
     
    733751\end{cquote}
    734752In this example, case 2 is always done if case 3 is done.
    735 This control flow is difficult to simulate with if statements or a ©switch© statement without fall-through as code must be duplicated or placed in a separate routine.
     753This control flow is difficult to simulate with ©if© statements or a ©switch© statement without fall-through as code must be duplicated or placed in a separate routine.
    736754C also uses fall-through to handle multiple case-values resulting in the same action:
    737755\begin{cfa}
    738756switch ( i ) {
    739   ®case 1: case 3: case 5:®     // odd values
     757  @case 1: case 3: case 5:@     // odd values
    740758        // odd action
    741759        break;
    742   ®case 2: case 4: case 6:®     // even values
     760  @case 2: case 4: case 6:@     // even values
    743761        // even action
    744762        break;
    745763}
    746764\end{cfa}
    747 However, this situation is handled in other languages without fall-through by allowing a list of case values.
    748 While fall-through itself is not a problem, the problem occurs when fall-through is the default, as this semantics is unintuitive to many programmers and is different from virtually all other programming languages with a ©switch© statement.
     765This situation better handled without fall-through by allowing a list of case values \see{\VRef{s:caseClause}}.
     766While fall-through itself is not a problem, the problem occurs when fall-through is the default, as this semantics is unintuitive to many programmers and is different from most programming languages with a ©switch© statement.
    749767Hence, default fall-through semantics results in a large number of programming errors as programmers often \emph{forget} the ©break© statement at the end of a ©case© clause, resulting in inadvertent fall-through.
    750768
     
    756774        if ( j < k ) {
    757775                ...
    758           ®case 1:®             // transfer into "if" statement
     776          @case 1:@             // transfer into "if" statement
    759777                ...
    760778        } // if
     
    762780        while ( j < 5 ) {
    763781                ...
    764           ®case 3:®             // transfer into "while" statement
     782          @case 3:@             // transfer into "while" statement
    765783                ...
    766784        } // while
    767785} // switch
    768786\end{cfa}
    769 The problem with this usage is branching into control structures, which is known to cause both comprehension and technical difficulties.
    770 The comprehension problem occurs from the inability to determine how control reaches a particular point due to the number of branches leading to it.
     787This usage branches into control structures, which is known to cause both comprehension and technical difficulties.
     788The comprehension problem results from the inability to determine how control reaches a particular point due to the number of branches leading to it.
    771789The technical problem results from the inability to ensure declaration and initialization of variables when blocks are not entered at the beginning.
    772 There are no positive arguments for this kind of control flow, and therefore, there is a strong impetus to eliminate it.
     790There are few arguments for this kind of control flow, and therefore, there is a strong impetus to eliminate it.
    773791Nevertheless, C does have an idiom where this capability is used, known as ``\Index*{Duff's device}''~\cite{Duff83}:
    774792\begin{cfa}
     
    794812\item
    795813It is possible to place the ©default© clause anywhere in the list of labelled clauses for a ©switch© statement, rather than only at the end.
    796 Virtually all programming languages with a ©switch© statement require the ©default© clause to appear last in the case-clause list.
     814Most programming languages with a ©switch© statement require the ©default© clause to appear last in the case-clause list.
    797815The logic for this semantics is that after checking all the ©case© clauses without success, the ©default© clause is selected;
    798816hence, physically placing the ©default© clause at the end of the ©case© clause list matches with this semantics.
     
    803821\begin{cfa}
    804822switch ( x ) {
    805         ®int y = 1;® §\C{// unreachable initialization}§
    806         ®x = 7;® §\C{// unreachable code without label/branch}§
     823        @int y = 1;@ $\C{// unreachable initialization}$
     824        @x = 7;@ $\C{// unreachable code without label/branch}$
    807825  case 0: ...
    808826        ...
    809         ®int z = 0;® §\C{// unreachable initialization, cannot appear after case}§
     827        @int z = 0;@ $\C{// unreachable initialization, cannot appear after case}$
    810828        z = 2;
    811829  case 1:
    812         ®x = z;® §\C{// without fall through, z is uninitialized}§
     830        @x = z;@ $\C{// without fall through, z is uninitialized}$
    813831}
    814832\end{cfa}
    815833While the declaration of the local variable ©y© is useful with a scope across all ©case© clauses, the initialization for such a variable is defined to never be executed because control always transfers over it.
    816 Furthermore, any statements before the first ©case© clause can only be executed if labelled and transferred to using a ©goto©, either from outside or inside of the ©switch©, both of which are problematic.
    817 As well, the declaration of ©z© cannot occur after the ©case© because a label can only be attached to a statement, and without a fall through to case 3, ©z© is uninitialized.
    818 The key observation is that the ©switch© statement branches into control structure, \ie there are multiple entry points into its statement body.
     834Furthermore, any statements before the first ©case© clause can only be executed if labelled and transferred to using a ©goto©, either from outside or inside of the ©switch©, where both are problematic.
     835As well, the declaration of ©z© cannot occur after the ©case© because a label can only be attached to a statement, and without a fall-through to case 3, ©z© is uninitialized.
     836The key observation is that the ©switch© statement branches into a control structure, \ie there are multiple entry points into its statement body.
    819837\end{enumerate}
    820838
     
    842860Therefore, to preserve backwards compatibility, it is necessary to introduce a new kind of ©switch© statement, called ©choose©, with no implicit fall-through semantics and an explicit fall-through if the last statement of a case-clause ends with the new keyword ©fallthrough©/©fallthru©, \eg:
    843861\begin{cfa}
    844 ®choose® ( i ) {
     862@choose@ ( i ) {
    845863  case 1:  case 2:  case 3:
    846864        ...
    847         ®// implicit end of switch (break)
    848   ®case 5:
     865        @// implicit end of switch (break)
     866  @case 5:
    849867        ...
    850         ®fallthru®; §\C{// explicit fall through}§
     868        @fallthru@; $\C{// explicit fall through}$
    851869  case 7:
    852870        ...
    853         ®break® §\C{// explicit end of switch (redundant)}§
     871        @break@ $\C{// explicit end of switch (redundant)}$
    854872  default:
    855873        j = 3;
    856874}
    857875\end{cfa}
    858 Like the ©switch© statement, the ©choose© statement retains the fall-through semantics for a list of ©case© clauses;
     876Like the ©switch© statement, the ©choose© statement retains the fall-through semantics for a list of ©case© clauses.
    859877An implicit ©break© is applied only at the end of the \emph{statements} following a ©case© clause.
    860878An explicit ©fallthru© is retained because it is a C-idiom most C programmers expect, and its absence might discourage programmers from using the ©choose© statement.
     
    872890\begin{cfa}
    873891switch ( x ) {
    874         ®int i = 0;® §\C{// allowed only at start}§
     892        @int i = 0;@ $\C{// allowed only at start}$
    875893  case 0:
    876894        ...
    877         ®int j = 0;® §\C{// disallowed}§
     895        @int j = 0;@ $\C{// disallowed}$
    878896  case 1:
    879897        {
    880                 ®int k = 0;® §\C{// allowed at different nesting levels}§
     898                @int k = 0;@ $\C{// allowed at different nesting levels}$
    881899                ...
    882           ®case 2:® §\C{// disallow case in nested statements}§
     900          @case 2:@ $\C{// disallow case in nested statements}$
    883901        }
    884902  ...
     
    897915  case 3:
    898916        if ( ... ) {
    899                 ... ®fallthru;® // goto case 4
     917                ... @fallthru;@ // goto case 4
    900918        } else {
    901919                ...
     
    912930choose ( ... ) {
    913931  case 3:
    914         ... ®fallthrough common;®
     932        ... @fallthrough common;@
    915933  case 4:
    916         ... ®fallthrough common;®
    917 
    918   ®common:® // below fallthrough
     934        ... @fallthrough common;@
     935
     936  @common:@ // below fallthrough
    919937                          // at case-clause level
    920938        ...     // common code for cases 3/4
     
    932950                for ( ... ) {
    933951                        // multi-level transfer
    934                         ... ®fallthru common;®
     952                        ... @fallthru common;@
    935953                }
    936954                ...
    937955        }
    938956        ...
    939   ®common:® // below fallthrough
     957  @common:@ // below fallthrough
    940958                          // at case-clause level
    941959\end{cfa}
     
    948966
    949967\begin{figure}
    950 \begin{tabular}{@{}l|l@{}}
    951 \multicolumn{1}{c|}{loop control} & \multicolumn{1}{c}{output} \\
     968\begin{tabular}{@{}l@{\hspace{25pt}}|l@{}}
     969\multicolumn{1}{@{}c@{\hspace{25pt}}|}{loop control} & \multicolumn{1}{c@{}}{output} \\
    952970\hline
    953 \begin{cfa}[xleftmargin=0pt]
    954 while ®()® { sout | "empty"; break; }
    955 do { sout | "empty"; break; } while ®()®;
    956 for ®()® { sout | "empty"; break; }
    957 for ( ®0® ) { sout | "A"; } sout | "zero";
    958 for ( ®1® ) { sout | "A"; }
    959 for ( ®10® ) { sout | "A"; }
    960 for ( ®= 10® ) { sout | "A"; }
    961 for ( ®1 ~= 10 ~ 2® ) { sout | "B"; }
    962 for ( ®10 -~= 1 ~ 2® ) { sout | "C"; }
    963 for ( ®0.5 ~ 5.5® ) { sout | "D"; }
    964 for ( ®5.5 -~ 0.5® ) { sout | "E"; }
    965 for ( ®i; 10® ) { sout | i; }
    966 for ( ®i; = 10® ) { sout | i; }
    967 for ( ®i; 1 ~= 10 ~ 2® ) { sout | i; }
    968 for ( ®i; 10 -~= 1 ~ 2® ) { sout | i; }
    969 for ( ®i; 0.5 ~ 5.5® ) { sout | i; }
    970 for ( ®i; 5.5 -~ 0.5® ) { sout | i; }
    971 for ( ®ui; 2u ~= 10u ~ 2u® ) { sout | ui; }
    972 for ( ®ui; 10u -~= 2u ~ 2u® ) { sout | ui; }
     971\begin{cfa}
     972while @($\,$)@ { sout | "empty"; break; }
     973do { sout | "empty"; break; } while @($\,$)@;
     974for @($\,$)@ { sout | "empty"; break; }
     975for ( @0@ ) { sout | "A"; } sout | "zero";
     976for ( @1@ ) { sout | "A"; }
     977for ( @10@ ) { sout | "A"; }
     978for ( @= 10@ ) { sout | "A"; }
     979for ( @1 ~= 10 ~ 2@ ) { sout | "B"; }
     980for ( @10 -~= 1 ~ 2@ ) { sout | "C"; }
     981for ( @0.5 ~ 5.5@ ) { sout | "D"; }
     982for ( @5.5 -~ 0.5@ ) { sout | "E"; }
     983for ( @i; 10@ ) { sout | i; }
     984for ( @i; = 10@ ) { sout | i; }
     985for ( @i; 1 ~= 10 ~ 2@ ) { sout | i; }
     986for ( @i; 10 -~= 1 ~ 2@ ) { sout | i; }
     987for ( @i; 0.5 ~ 5.5@ ) { sout | i; }
     988for ( @i; 5.5 -~ 0.5@ ) { sout | i; }
     989for ( @ui; 2u ~= 10u ~ 2u@ ) { sout | ui; }
     990for ( @ui; 10u -~= 2u ~ 2u@ ) { sout | ui; }
    973991enum { N = 10 };
    974 for ( ®N® ) { sout | "N"; }
    975 for ( ®i; N® ) { sout | i; }
    976 for ( ®i; N -~ 0® ) { sout | i; }
     992for ( @N@ ) { sout | "N"; }
     993for ( @i; N@ ) { sout | i; }
     994for ( @i; N -~ 0@ ) { sout | i; }
    977995const int start = 3, comp = 10, inc = 2;
    978 for ( ®i; start ~ comp ~ inc + 1® ) { sout | i; }
    979 for ( i; 1 ~ ®@® ) { if ( i > 10 ) break; sout | i; }
    980 for ( i; 10 -~ ®@® ) { if ( i < 0 ) break; sout | i; }
    981 for ( i; 2 ~ ®@® ~ 2 ) { if ( i > 10 ) break; sout | i; }
    982 for ( i; 2.1 ~ ®@® ~ ®@® ) { if ( i > 10.5 ) break; sout | i; i += 1.7; }
    983 for ( i; 10 -~ ®@® ~ 2 ) { if ( i < 0 ) break; sout | i; }
    984 for ( i; 12.1 ~ ®@® ~ ®@® ) { if ( i < 2.5 ) break; sout | i; i -= 1.7; }
    985 for ( i; 5 ®:® j; -5 ~ @ ) { sout | i | j; }
    986 for ( i; 5 ®:® j; -5 -~ @ ) { sout | i | j; }
    987 for ( i; 5 ®:® j; -5 ~ @ ~ 2 ) { sout | i | j; }
    988 for ( i; 5 ®:® j; -5 -~ @ ~ 2 ) { sout | i | j; }
    989 for ( i; 5 ®:® j; -5 ~ @ ) { sout | i | j; }
    990 for ( i; 5 ®:® j; -5 -~ @ ) { sout | i | j; }
    991 for ( i; 5 ®:® j; -5 ~ @ ~ 2 ) { sout | i | j; }
    992 for ( i; 5 ®:® j; -5 -~ @ ~ 2 ) { sout | i | j; }
    993 for ( i; 5 ®:® j; -5 -~ @ ~ 2 ®:® k; 1.5 ~ @ ) { sout | i | j | k; }
    994 for ( i; 5 ®:® j; -5 -~ @ ~ 2 ®:® k; 1.5 ~ @ ) { sout | i | j | k; }
    995 for ( i; 5 ®:® k; 1.5 ~ @ ®:® j; -5 -~ @ ~ 2 ) { sout | i | j | k; }
     996for ( @i; start ~ comp ~ inc + 1@ ) { sout | i; }
     997for ( i; 1 ~ $\R{@}$ ) { if ( i > 10 ) break; sout | i; }
     998for ( i; 10 -~ $\R{@}$ ) { if ( i < 0 ) break; sout | i; }
     999for ( i; 2 ~ $\R{@}$ ~ 2 ) { if ( i > 10 ) break; sout | i; }
     1000for ( i; 2.1 ~ $\R{@}$ ~ $\R{@}$ ) { if ( i > 10.5 ) break; sout | i; i += 1.7; }
     1001for ( i; 10 -~ $\R{@}$ ~ 2 ) { if ( i < 0 ) break; sout | i; }
     1002for ( i; 12.1 ~ $\R{@}$ ~ $\R{@}$ ) { if ( i < 2.5 ) break; sout | i; i -= 1.7; }
     1003for ( i; 5 @:@ j; -5 ~ $@$ ) { sout | i | j; }
     1004for ( i; 5 @:@ j; -5 -~ $@$ ) { sout | i | j; }
     1005for ( i; 5 @:@ j; -5 ~ $@$ ~ 2 ) { sout | i | j; }
     1006for ( i; 5 @:@ j; -5 -~ $@$ ~ 2 ) { sout | i | j; }
     1007for ( i; 5 @:@ j; -5 ~ $@$ ) { sout | i | j; }
     1008for ( i; 5 @:@ j; -5 -~ $@$ ) { sout | i | j; }
     1009for ( i; 5 @:@ j; -5 ~ $@$ ~ 2 ) { sout | i | j; }
     1010for ( i; 5 @:@ j; -5 -~ $@$ ~ 2 ) { sout | i | j; }
     1011for ( i; 5 @:@ j; -5 -~ $@$ ~ 2 @:@ k; 1.5 ~ $@$ ) { sout | i | j | k; }
     1012for ( i; 5 @:@ j; -5 -~ $@$ ~ 2 @:@ k; 1.5 ~ $@$ ) { sout | i | j | k; }
     1013for ( i; 5 @:@ k; 1.5 ~ $@$ @:@ j; -5 -~ $@$ ~ 2 ) { sout | i | j | k; }
    9961014\end{cfa}
    9971015&
     
    10561074\subsection{Loop Control}
    10571075
    1058 The ©for©/©while©/©do-while© loop-control allows empty or simplified ranges (see Figure~\ref{f:LoopControlExamples}).
    1059 \begin{itemize}
     1076Looping a fixed number of times, possibly with a loop index, occurs frequently.
     1077\CFA condenses simply looping to facilitate coding speed and safety.
     1078The ©for©/©while©/©do-while© loop-control is augmented as follows \see{examples in \VRef[Figure]{f:LoopControlExamples}}:
     1079\begin{itemize}[itemsep=0pt]
     1080\item
     1081©0© is the implicit start value;
     1082\item
     1083©1© is the implicit increment value.
     1084\item
     1085The up-to range uses operator ©+=© for increment;
     1086\item
     1087The down-to range uses operator ©-=© for decrement.
    10601088\item
    10611089The loop index is polymorphic in the type of the comparison value N (when the start value is implicit) or the start value M.
     1090\begin{cfa}
     1091for ( i; @5@ )                                  $\C[2.5in]{// typeof(5) i; 5 is comparison value}$
     1092for ( i; @1.5@~5.5~0.5 )                $\C{// typeof(1.5) i; 1.5 is start value}$
     1093\end{cfa}
    10621094\item
    10631095An empty conditional implies comparison value of ©1© (true).
    1064 \item
    1065 A comparison N is implicit up-to exclusive range [0,N©®)®©.
    1066 \item
    1067 A comparison ©=© N is implicit up-to inclusive range [0,N©®]®©.
    1068 \item
    1069 The up-to range M ©~©\index{~@©~©} N means exclusive range [M,N©®)®©.
    1070 \item
    1071 The up-to range M ©~=©\index{~=@©~=©} N means inclusive range [M,N©®]®©.
    1072 \item
    1073 The down-to range M ©-~©\index{-~@©-~©} N means exclusive range [N,M©®)®©.
    1074 \item
    1075 The down-to range M ©-~=©\index{-~=@©-~=©} N means inclusive range [N,M©®]®©.
    1076 \item
    1077 ©0© is the implicit start value;
    1078 \item
    1079 ©1© is the implicit increment value.
    1080 \item
    1081 The up-to range uses operator ©+=© for increment;
    1082 \item
    1083 The down-to range uses operator ©-=© for decrement.
     1096\begin{cfa}
     1097while ( $\R{/*empty*/}$ )               $\C{// while ( true )}$
     1098for ( $\R{/*empty*/}$ )                 $\C{// for ( ; true; )}$
     1099do ... while ( $\R{/*empty*/}$ ) $\C{// do ... while ( true )}$
     1100\end{cfa}
     1101\item
     1102A comparison N is implicit up-to exclusive range [0,N\R{)}.
     1103\begin{cfa}
     1104for ( @5@ )                                             $\C{// for ( typeof(5) i; i < 5; i += 1 )}$
     1105\end{cfa}
     1106\item
     1107A comparison ©=© N is implicit up-to inclusive range [0,N\R{]}.
     1108\begin{cfa}
     1109for ( @=@5 )                                    $\C{// for ( typeof(5) i; i <= 5; i += 1 )}$
     1110\end{cfa}
     1111\item
     1112The up-to range M ©~©\index{~@©~©} N means exclusive range [M,N\R{)}.
     1113\begin{cfa}
     1114for ( 1@~@5 )                                   $\C{// for ( typeof(1) i = 1; i < 5; i += 1 )}$
     1115\end{cfa}
     1116\item
     1117The up-to range M ©~=©\index{~=@©~=©} N means inclusive range [M,N\R{]}.
     1118\begin{cfa}
     1119for ( 1@~=@5 )                                  $\C{// for ( typeof(1) i = 1; i <= 5; i += 1 )}$
     1120\end{cfa}
     1121\item
     1122The down-to range M ©-~©\index{-~@©-~©} N means exclusive range [N,M\R{)}.
     1123\begin{cfa}
     1124for ( 1@-~@5 )                                  $\C{// for ( typeof(1) i = 5; i > 0; i -= 1 )}$
     1125\end{cfa}
     1126\item
     1127The down-to range M ©-~=©\index{-~=@©-~=©} N means inclusive range [N,M\R{]}.
     1128\begin{cfa}
     1129for ( 1@-~=@5 )                                 $\C{// for ( typeof(1) i = 5; i >= 0; i -= 1 )}$
     1130\end{cfa}
    10841131\item
    10851132©@© means put nothing in this field.
     1133\begin{cfa}
     1134for ( 1~$\R{@}$~2 )                             $\C{// for ( typeof(1) i = 1; /*empty*/; i += 2 )}$
     1135\end{cfa}
    10861136\item
    10871137©:© means start another index.
     1138\begin{cfa}
     1139for ( i; 5 @:@ j; 2~12~3 )              $\C{// for ( typeof(i) i = 1, j = 2; i < 5 \&\& j < 12; i += 1, j += 3 )}\CRT$
     1140\end{cfa}
    10881141\end{itemize}
    10891142
     
    10921145\subsection{\texorpdfstring{Labelled \LstKeywordStyle{continue} / \LstKeywordStyle{break} Statement}{Labelled continue / break Statement}}
    10931146
    1094 While C provides ©continue© and ©break© statements for altering control flow, both are restricted to one level of nesting for a particular control structure.
    1095 Unfortunately, this restriction forces programmers to use \Indexc{goto} to achieve the equivalent control-flow for more than one level of nesting.
     1147C ©continue© and ©break© statements, for altering control flow, are restricted to one level of nesting for a particular control structure.
     1148This restriction forces programmers to use \Indexc{goto} to achieve the equivalent control-flow for more than one level of nesting.
    10961149To prevent having to switch to the ©goto©, \CFA extends the \Indexc{continue}\index{continue@©continue©!labelled}\index{labelled!continue@©continue©} and \Indexc{break}\index{break@©break©!labelled}\index{labelled!break@©break©} with a target label to support static multi-level exit\index{multi-level exit}\index{static multi-level exit}~\cite{Buhr85}, as in Java.
    10971150For both ©continue© and ©break©, the target label must be directly associated with a ©for©, ©while© or ©do© statement;
    10981151for ©break©, the target label can also be associated with a ©switch©, ©if© or compound (©{}©) statement.
    1099 \VRef[Figure]{f:MultiLevelExit} shows ©continue© and ©break© indicating the specific control structure, and the corresponding C program using only ©goto© and labels.
     1152\VRef[Figure]{f:MultiLevelExit} shows a comparison between labelled ©continue© and ©break© and the corresponding C equivalent using ©goto© and labels.
    11001153The innermost loop has 8 exit points, which cause continuation or termination of one or more of the 7 \Index{nested control-structure}s.
    11011154
     
    11041157\begin{lrbox}{\myboxA}
    11051158\begin{cfa}[tabsize=3]
    1106 ®Compound:® {
    1107         ®Try:® try {
    1108                 ®For:® for ( ... ) {
    1109                         ®While:® while ( ... ) {
    1110                                 ®Do:® do {
    1111                                         ®If:® if ( ... ) {
    1112                                                 ®Switch:® switch ( ... ) {
     1159@Compound:@ {
     1160        @Try:@ try {
     1161                @For:@ for ( ... ) {
     1162                        @While:@ while ( ... ) {
     1163                                @Do:@ do {
     1164                                        @If:@ if ( ... ) {
     1165                                                @Switch:@ switch ( ... ) {
    11131166                                                        case 3:
    1114                                                                 ®break Compound®;
    1115                                                                 ®break Try®;
    1116                                                                 ®break For®;      /* or */  ®continue For®;
    1117                                                                 ®break While®;  /* or */  ®continue While®;
    1118                                                                 ®break Do®;      /* or */  ®continue Do®;
    1119                                                                 ®break If®;
    1120                                                                 ®break Switch®;
     1167                                                                @break Compound@;
     1168                                                                @break Try@;
     1169                                                                @break For@;      /* or */  @continue For@;
     1170                                                                @break While@;  /* or */  @continue While@;
     1171                                                                @break Do@;      /* or */  @continue Do@;
     1172                                                                @break If@;
     1173                                                                @break Switch@;
    11211174                                                        } // switch
    11221175                                                } else {
    1123                                                         ... ®break If®; ...     // terminate if
     1176                                                        ... @break If@; ...     // terminate if
    11241177                                                } // if
    11251178                                } while ( ... ); // do
    11261179                        } // while
    11271180                } // for
    1128         } ®finally® { // always executed
     1181        } @finally@ { // always executed
    11291182        } // try
    11301183} // compound
     
    11361189{
    11371190
    1138                 ®ForC:® for ( ... ) {
    1139                         ®WhileC:® while ( ... ) {
    1140                                 ®DoC:® do {
     1191                @ForC:@ for ( ... ) {
     1192                        @WhileC:@ while ( ... ) {
     1193                                @DoC:@ do {
    11411194                                        if ( ... ) {
    11421195                                                switch ( ... ) {
    11431196                                                        case 3:
    1144                                                                 ®goto Compound®;
    1145                                                                 ®goto Try®;
    1146                                                                 ®goto ForB®;      /* or */  ®goto ForC®;
    1147                                                                 ®goto WhileB®;  /* or */  ®goto WhileC®;
    1148                                                                 ®goto DoB®;      /* or */  ®goto DoC®;
    1149                                                                 ®goto If®;
    1150                                                                 ®goto Switch®;
    1151                                                         } ®Switch:® ;
     1197                                                                @goto Compound@;
     1198                                                                @goto Try@;
     1199                                                                @goto ForB@;      /* or */  @goto ForC@;
     1200                                                                @goto WhileB@;  /* or */  @goto WhileC@;
     1201                                                                @goto DoB@;      /* or */  @goto DoC@;
     1202                                                                @goto If@;
     1203                                                                @goto Switch@;
     1204                                                        } @Switch:@ ;
    11521205                                                } else {
    1153                                                         ... ®goto If®; ...      // terminate if
    1154                                                 } ®If:®;
    1155                                 } while ( ... ); ®DoB:® ;
    1156                         } ®WhileB:® ;
    1157                 } ®ForB:® ;
    1158 
    1159 
    1160 } ®Compound:® ;
     1206                                                        ... @goto If@; ...      // terminate if
     1207                                                } @If:@;
     1208                                } while ( ... ); @DoB:@ ;
     1209                        } @WhileB:@ ;
     1210                } @ForB:@ ;
     1211
     1212
     1213} @Compound:@ ;
    11611214\end{cfa}
    11621215\end{lrbox}
    11631216
    11641217\subfloat[\CFA]{\label{f:CFibonacci}\usebox\myboxA}
    1165 \hspace{2pt}
     1218\hspace{3pt}
    11661219\vrule
    1167 \hspace{2pt}
     1220\hspace{3pt}
    11681221\subfloat[C]{\label{f:CFAFibonacciGen}\usebox\myboxB}
    11691222\caption{Multi-level Exit}
     
    11801233This restriction prevents missing declarations and/or initializations at the start of a control structure resulting in undefined behaviour.
    11811234\end{itemize}
    1182 The advantage of the labelled ©continue©/©break© is allowing static multi-level exits without having to use the ©goto© statement, and tying control flow to the target control structure rather than an arbitrary point in a program.
     1235The advantage of the labelled ©continue©/©break© is allowing static multi-level exits without having to use the ©goto© statement, and tying control flow to the target control structure rather than an arbitrary point in a program via a label.
    11831236Furthermore, the location of the label at the \emph{beginning} of the target control structure informs the reader (\Index{eye candy}) that complex control-flow is occurring in the body of the control structure.
    11841237With ©goto©, the label is at the end of the control structure, which fails to convey this important clue early enough to the reader.
     
    11871240
    11881241
    1189 %\section{\texorpdfstring{\protect\lstinline@with@ Statement}{with Statement}}
    1190 \section{\texorpdfstring{\LstKeywordStyle{with} Statement}{with Statement}}
     1242%\subsection{\texorpdfstring{\protect\lstinline@with@ Statement}{with Statement}}
     1243\subsection{\texorpdfstring{\LstKeywordStyle{with} Statement}{with Statement}}
    11911244\label{s:WithStatement}
    11921245
    1193 Grouping heterogeneous data into \newterm{aggregate}s (structure/union) is a common programming practice, and an aggregate can be further organized into more complex structures, such as arrays and containers:
    1194 \begin{cfa}
    1195 struct S { §\C{// aggregate}§
    1196         char c; §\C{// fields}§
    1197         int i;
    1198         double d;
     1246Grouping heterogeneous data into an \newterm{aggregate} (structure/union) is a common programming practice, and aggregates may be nested:
     1247\begin{cfa}
     1248struct Person {                                                         $\C{// aggregate}$
     1249        struct Name { char first[20], last[20]; } name $\C{// nesting}$
     1250        struct Address { ... } address                  $\C{// nesting}$
     1251        int sex;
    11991252};
    1200 S s, as[10];
    1201 \end{cfa}
    1202 However, functions manipulating aggregates must repeat the aggregate name to access its containing fields:
    1203 \begin{cfa}
    1204 void f( S s ) {
    1205         ®s.®c; ®s.®i; ®s.®d; §\C{// access containing fields}§
    1206 }
    1207 \end{cfa}
    1208 which extends to multiple levels of qualification for nested aggregates.
    1209 A similar situation occurs in object-oriented programming, \eg \CC:
     1253\end{cfa}
     1254Functions manipulating aggregates must repeat the aggregate name to access its containing fields.
     1255\begin{cfa}
     1256Person p
     1257@p.@name; @p.@address; @p.@sex; $\C{// access containing fields}$
     1258\end{cfa}
     1259which extends to multiple levels of qualification for nested aggregates and multiple aggregates.
     1260\begin{cfa}
     1261struct Ticket { ... } t;
     1262@p.name@.first; @p.address@.street;             $\C{// access nested fields}$
     1263@t.@departure; @t.@cost;                                $\C{// access multiple aggregate}$
     1264\end{cfa}
     1265Repeated aggregate qualification is tedious and makes code difficult to read.
     1266Therefore, reducing aggregate qualification is a useful language design goal.
     1267
     1268C allows unnamed nested aggregates that open their scope into the containing aggregate.
     1269This feature is used to group fields for attributes and/or with ©union© aggregates.
     1270\begin{cfa}
     1271struct S {
     1272        struct { int g,  h; } __attribute__(( aligned(64) ));
     1273        int tag;
     1274        union {
     1275                struct { char c1,  c2; } __attribute__(( aligned(128) ));
     1276                struct { int i1,  i2; };
     1277                struct { double d1,  d2; };
     1278        };
     1279};
     1280s.g; s.h; s.tag; s.c1; s.c2; s.i1; s.i2; s.d1; s.d2;
     1281\end{cfa}
     1282
     1283Object-oriented languages reduce qualification for class variables within member functions, \eg \CC:
    12101284\begin{C++}
    12111285struct S {
    1212         char c; §\C{// fields}§
    1213         int i;
    1214         double d;
    1215         void f() { §\C{// implicit ``this'' aggregate}§
    1216                 ®this->®c; ®this->®i; ®this->®d; §\C{// access containing fields}§
     1286        char @c@;   int @i@;   double @d@;
     1287        void f( /* S * this */ ) {                              $\C{// implicit ``this'' parameter}$
     1288                @c@;   @i@;   @d@;                                      $\C{// this->c; this->i; this->d;}$
    12171289        }
    12181290}
    12191291\end{C++}
    1220 Object-oriented nesting of member functions in a \lstinline[language=C++]@class/struct@ allows eliding \lstinline[language=C++]@this->@ because of lexical scoping.
    1221 However, for other aggregate parameters, qualification is necessary:
    1222 \begin{cfa}
    1223 struct T { double m, n; };
    1224 int S::f( T & t ) { §\C{// multiple aggregate parameters}§
    1225         c; i; d; §\C{\color{red}// this--{\textgreater}.c, this--{\textgreater}.i, this--{\textgreater}.d}§
    1226         ®t.®m; ®t.®n; §\C{// must qualify}§
    1227 }
    1228 \end{cfa}
    1229 
    1230 To simplify the programmer experience, \CFA provides a ©with© statement (see Pascal~\cite[\S~4.F]{Pascal}) to elide aggregate qualification to fields by opening a scope containing the field identifiers.
    1231 Hence, the qualified fields become variables with the side-effect that it is easier to optimizing field references in a block.
    1232 \begin{cfa}
    1233 void f( S & this ) ®with ( this )® { §\C{// with statement}§
    1234         c; i; d; §\C{\color{red}// this.c, this.i, this.d}§
     1292In general, qualification is elided for the variables and functions in the lexical scopes visible from a member function.
     1293However, qualification is necessary for name shadowing and explicit aggregate parameters.
     1294\begin{cfa}
     1295struct T {
     1296        char @m@;   int @i@;   double @n@;              $\C{// derived class variables}$
     1297};
     1298struct S : public T {
     1299        char @c@;   int @i@;   double @d@;              $\C{// class variables}$
     1300        void g( double @d@, T & t ) {
     1301                d;   @t@.m;   @t@.i;   @t@.n;           $\C{// function parameter}$
     1302                c;   i;   @this->@d;   @S::@d;          $\C{// class S variables}$
     1303                m;   @T::@i;   n;                                       $\C{// class T variables}$
     1304        }
     1305};
     1306\end{cfa}
     1307Note the three different forms of qualification syntax in \CC, ©.©, ©->©, ©::©, which is confusing.
     1308
     1309Since \CFA in not object-oriented, it has no implicit parameter with its implicit qualification.
     1310Instead \CFA introduces a general mechanism using the ©with© statement \see{Pascal~\cite[\S~4.F]{Pascal}} to explicitly elide aggregate qualification by opening a scope containing the field identifiers.
     1311Hence, the qualified fields become variables with the side-effect that it is simpler to write, easier to read, and optimize field references in a block.
     1312\begin{cfa}
     1313void f( S & this ) @with ( this )@ {            $\C{// with statement}$
     1314        @c@;   @i@;   @d@;                                              $\C{// this.c, this.i, this.d}$
    12351315}
    12361316\end{cfa}
    12371317with the generality of opening multiple aggregate-parameters:
    12381318\begin{cfa}
    1239 void f( S & s, T & t ) ®with ( s, t )® { §\C{// multiple aggregate parameters}§
    1240         c; i; d; §\C{\color{red}// s.c, s.i, s.d}§
    1241         m; n; §\C{\color{red}// t.m, t.n}§
    1242 }
    1243 \end{cfa}
    1244 
    1245 In detail, the ©with© statement has the form:
    1246 \begin{cfa}
    1247 §\emph{with-statement}§:
    1248         'with' '(' §\emph{expression-list}§ ')' §\emph{compound-statement}§
    1249 \end{cfa}
    1250 and may appear as the body of a function or nested within a function body.
    1251 Each expression in the expression-list provides a type and object.
    1252 The type must be an aggregate type.
     1319void g( S & s, T & t ) @with ( s, t )@ {        $\C{// multiple aggregate parameters}$
     1320        c;   @s.@i;   d;                                                $\C{// s.c, s.i, s.d}$
     1321        m;   @t.@i;   n;                                                $\C{// t.m, t.i, t.n}$
     1322}
     1323\end{cfa}
     1324where qualification is only necessary to disambiguate the shadowed variable ©i©.
     1325
     1326In detail, the ©with© statement may appear as the body of a function or nested within a function body.
     1327The ©with© clause takes a list of expressions, where each expression provides an aggregate type and object.
    12531328(Enumerations are already opened.)
    1254 The object is the implicit qualifier for the open structure-fields.
    1255 
     1329To open a pointer type, the pointer must be dereferenced to obtain a reference to the aggregate type.
     1330\begin{cfa}
     1331S * sp;
     1332with ( *sp ) { ... }
     1333\end{cfa}
     1334The expression object is the implicit qualifier for the open structure-fields.
     1335\CFA's ability to overload variables \see{\VRef{s:VariableOverload}} and use the left-side of assignment in type resolution means most fields with the same name but different types are automatically disambiguated, eliminating qualification.
    12561336All expressions in the expression list are open in parallel within the compound statement.
    12571337This semantic is different from Pascal, which nests the openings from left to right.
    12581338The difference between parallel and nesting occurs for fields with the same name and type:
    12591339\begin{cfa}
    1260 struct S { int ®i®; int j; double m; } s, w;
    1261 struct T { int ®i®; int k; int m; } t, w;
    1262 with ( s, t ) {
    1263         j + k; §\C{// unambiguous, s.j + t.k}§
    1264         m = 5.0; §\C{// unambiguous, t.m = 5.0}§
    1265         m = 1; §\C{// unambiguous, s.m = 1}§
    1266         int a = m; §\C{// unambiguous, a = s.i }§
    1267         double b = m; §\C{// unambiguous, b = t.m}§
    1268         int c = s.i + t.i; §\C{// unambiguous, qualification}§
    1269         (double)m; §\C{// unambiguous, cast}§
    1270 }
    1271 \end{cfa}
    1272 For parallel semantics, both ©s.i© and ©t.i© are visible, so ©i© is ambiguous without qualification;
    1273 for nested semantics, ©t.i© hides ©s.i©, so ©i© implies ©t.i©.
    1274 \CFA's ability to overload variables means fields with the same name but different types are automatically disambiguated, eliminating most qualification when opening multiple aggregates.
    1275 Qualification or a cast is used to disambiguate.
    1276 
    1277 There is an interesting problem between parameters and the function-body ©with©, \eg:
    1278 \begin{cfa}
    1279 void ?{}( S & s, int i ) with ( s ) { §\C{// constructor}§
    1280         ®s.i = i;®  j = 3;  m = 5.5; §\C{// initialize fields}§
     1340struct Q { int @i@; int k; int @m@; } q, w;
     1341struct R { int @i@; int j; double @m@; } r, w;
     1342with ( r, q ) {
     1343        j + k;                                                                  $\C{// unambiguous, r.j + q.k}$
     1344        m = 5.0;                                                                $\C{// unambiguous, q.m = 5.0}$
     1345        m = 1;                                                                  $\C{// unambiguous, r.m = 1}$
     1346        int a = m;                                                              $\C{// unambiguous, a = r.i }$
     1347        double b = m;                                                   $\C{// unambiguous, b = q.m}$
     1348        int c = r.i + q.i;                                              $\C{// disambiguate with qualification}$
     1349        (double)m;                                                              $\C{// disambiguate with cast}$
     1350}
     1351\end{cfa}
     1352For parallel semantics, both ©r.i© and ©q.i© are visible, so ©i© is ambiguous without qualification;
     1353for nested semantics, ©q.i© hides ©r.i©, so ©i© implies ©q.i©.
     1354Pascal nested-semantics is possible by nesting ©with© statements.
     1355\begin{cfa}
     1356with ( r ) {
     1357        i;                                                                              $\C{// unambiguous, r.i}$
     1358        with ( q ) {
     1359                i;                                                                      $\C{// unambiguous, q.i}$
     1360        }
     1361}
     1362\end{cfa}
     1363A cast or qualification can be used to disambiguate variables within a ©with© \emph{statement}.
     1364A cast can be used to disambiguate among overload variables in a ©with© \emph{expression}:
     1365\begin{cfa}
     1366with ( w ) { ... }                                                      $\C{// ambiguous, same name and no context}$
     1367with ( (Q)w ) { ... }                                           $\C{// unambiguous, cast}$
     1368\end{cfa}
     1369Because there is no left-side in the ©with© expression to implicitly disambiguate between the ©w© variables, it is necessary to explicitly disambiguate by casting ©w© to type ©Q© or ©R©.
     1370
     1371Finally, there is an interesting problem between parameters and the function-body ©with©, \eg:
     1372\begin{cfa}
     1373void ?{}( S & s, int i ) with ( s ) { $\C{// constructor}$
     1374        @s.i = i;@  j = 3;  m = 5.5; $\C{// initialize fields}$
    12811375}
    12821376\end{cfa}
     
    12911385and implicitly opened \emph{after} a function-body open, to give them higher priority:
    12921386\begin{cfa}
    1293 void ?{}( S & s, int ®i® ) with ( s ) ®with( §\emph{\color{red}params}§ )® {
    1294         s.i = ®i®; j = 3; m = 5.5;
    1295 }
    1296 \end{cfa}
    1297 Finally, a cast may be used to disambiguate among overload variables in a ©with© expression:
    1298 \begin{cfa}
    1299 with ( w ) { ... } §\C{// ambiguous, same name and no context}§
    1300 with ( (S)w ) { ... } §\C{// unambiguous, cast}§
    1301 \end{cfa}
    1302 and ©with© expressions may be complex expressions with type reference (see Section~\ref{s:References}) to aggregate:
    1303 % \begin{cfa}
    1304 % struct S { int i, j; } sv;
    1305 % with ( sv ) { §\C{// implicit reference}§
    1306 %       S & sr = sv;
    1307 %       with ( sr ) { §\C{// explicit reference}§
    1308 %               S * sp = &sv;
    1309 %               with ( *sp ) { §\C{// computed reference}§
    1310 %                       i = 3; j = 4; §\C{\color{red}// sp--{\textgreater}i, sp--{\textgreater}j}§
    1311 %               }
    1312 %               i = 2; j = 3; §\C{\color{red}// sr.i, sr.j}§
    1313 %       }
    1314 %       i = 1; j = 2; §\C{\color{red}// sv.i, sv.j}§
    1315 % }
    1316 % \end{cfa}
    1317 
    1318 In \Index{object-oriented} programming, there is an implicit first parameter, often names \textbf{©self©} or \textbf{©this©}, which is elided.
    1319 \begin{C++}
    1320 class C {
    1321         int i, j;
    1322         int mem() { §\C{\color{red}// implicit "this" parameter}§
    1323                 i = 1; §\C{\color{red}// this->i}§
    1324                 j = 2; §\C{\color{red}// this->j}§
    1325         }
    1326 }
    1327 \end{C++}
    1328 Since \CFA is non-object-oriented, the equivalent object-oriented program looks like:
    1329 \begin{cfa}
    1330 struct S { int i, j; };
    1331 int mem( S & ®this® ) { §\C{// explicit "this" parameter}§
    1332         ®this.®i = 1; §\C{// "this" is not elided}§
    1333         ®this.®j = 2;
    1334 }
    1335 \end{cfa}
    1336 but it is cumbersome having to write ``©this.©'' many times in a member.
    1337 
    1338 \CFA provides a ©with© clause/statement (see Pascal~\cite[\S~4.F]{Pascal}) to elided the "©this.©" by opening a scope containing field identifiers, changing the qualified fields into variables and giving an opportunity for optimizing qualified references.
    1339 \begin{cfa}
    1340 int mem( S & this ) ®with( this )® { §\C{// with clause}§
    1341         i = 1; §\C{\color{red}// this.i}§
    1342         j = 2; §\C{\color{red}// this.j}§
    1343 }
    1344 \end{cfa}
    1345 which extends to multiple routine parameters:
    1346 \begin{cfa}
    1347 struct T { double m, n; };
    1348 int mem2( S & this1, T & this2 ) ®with( this1, this2 )® {
    1349         i = 1; j = 2;
    1350         m = 1.0; n = 2.0;
    1351 }
    1352 \end{cfa}
    1353 
    1354 The statement form is used within a block:
    1355 \begin{cfa}
    1356 int foo() {
    1357         struct S1 { ... } s1;
    1358         struct S2 { ... } s2;
    1359         ®with( s1 )® { §\C{// with statement}§
    1360                 // access fields of s1 without qualification
    1361                 ®with s2® { §\C{// nesting}§
    1362                         // access fields of s1 and s2 without qualification
    1363                 }
    1364         }
    1365         ®with s1, s2® {
    1366                 // access unambiguous fields of s1 and s2 without qualification
    1367         }
    1368 }
    1369 \end{cfa}
    1370 
    1371 When opening multiple structures, fields with the same name and type are ambiguous and must be fully qualified.
    1372 For fields with the same name but different type, context/cast can be used to disambiguate.
    1373 \begin{cfa}
    1374 struct S { int i; int j; double m; } a, c;
    1375 struct T { int i; int k; int m } b, c;
    1376 with( a, b )
    1377 {
    1378 }
    1379 \end{cfa}
    1380 
    1381 \begin{comment}
    1382 The components in the "with" clause
    1383 
    1384   with a, b, c { ... }
    1385 
    1386 serve 2 purposes: each component provides a type and object. The type must be a
    1387 structure type. Enumerations are already opened, and I think a union is opened
    1388 to some extent, too. (Or is that just unnamed unions?) The object is the target
    1389 that the naked structure-fields apply to. The components are open in "parallel"
    1390 at the scope of the "with" clause/statement, so opening "a" does not affect
    1391 opening "b", etc. This semantic is different from Pascal, which nests the
    1392 openings.
    1393 
    1394 Having said the above, it seems reasonable to allow a "with" component to be an
    1395 expression. The type is the static expression-type and the object is the result
    1396 of the expression. Again, the type must be an aggregate. Expressions require
    1397 parenthesis around the components.
    1398 
    1399   with( a, b, c ) { ... }
    1400 
    1401 Does this now make sense?
    1402 
    1403 Having written more CFA code, it is becoming clear to me that I *really* want
    1404 the "with" to be implemented because I hate having to type all those object
    1405 names for fields. It's a great way to drive people away from the language.
    1406 \end{comment}
     1387void ?{}( S & s, int @i@ ) with ( s ) @with( $\emph{\R{params}}$ )@ { // syntax not allowed, illustration only
     1388        s.i = @i@; j = 3; m = 5.5;
     1389}
     1390\end{cfa}
     1391This implicit semantic matches with programmer expectation.
     1392
    14071393
    14081394
     
    14141400Non-local transfer can cause stack unwinding, \ie non-local routine termination, depending on the kind of raise.
    14151401\begin{cfa}
    1416 exception_t E {}; §\C{// exception type}§
     1402exception_t E {}; $\C{// exception type}$
    14171403void f(...) {
    1418         ... throw E{}; ... §\C{// termination}§
    1419         ... throwResume E{}; ... §\C{// resumption}§
     1404        ... throw E{}; ... $\C{// termination}$
     1405        ... throwResume E{}; ... $\C{// resumption}$
    14201406}
    14211407try {
    14221408        f(...);
    1423 } catch( E e ; §boolean-predicate§ ) {          §\C{// termination handler}§
     1409} catch( E e ; $boolean-predicate$ ) {          $\C{// termination handler}$
    14241410        // recover and continue
    1425 } catchResume( E e ; §boolean-predicate§ ) { §\C{// resumption handler}§
     1411} catchResume( E e ; $boolean-predicate$ ) { $\C{// resumption handler}$
    14261412        // repair and return
    14271413} finally {
     
    14301416\end{cfa}
    14311417The kind of raise and handler match: ©throw© with ©catch© and ©throwResume© with ©catchResume©.
    1432 Then the exception type must match along with any additonal predicate must be true.
     1418Then the exception type must match along with any additional predicate must be true.
    14331419The ©catch© and ©catchResume© handlers may appear in any oder.
    14341420However, the ©finally© clause must appear at the end of the ©try© statement.
     
    14831469For example, a routine returning a \Index{pointer} to an array of integers is defined and used in the following way:
    14841470\begin{cfa}
    1485 int ®(*®f®())[®5®]® {...}; §\C{// definition}§
    1486  ... ®(*®f®())[®3®]® += 1; §\C{// usage}§
     1471int @(*@f@())[@5@]@ {...}; $\C{// definition}$
     1472 ... @(*@f@())[@3@]@ += 1; $\C{// usage}$
    14871473\end{cfa}
    14881474Essentially, the return type is wrapped around the routine name in successive layers (like an \Index{onion}).
     
    14991485\begin{tabular}{@{}l@{\hspace{3em}}l@{}}
    15001486\multicolumn{1}{c@{\hspace{3em}}}{\textbf{\CFA}}        & \multicolumn{1}{c}{\textbf{C}}        \\
    1501 \begin{cfa}
    1502 ß[5] *ß ®int® x1;
    1503 ß* [5]ß ®int® x2;
    1504 ß[* [5] int]ß f®( int p )®;
     1487\begin{cfa}[moredelim={**[is][\color{blue}]{\#}{\#}}]
     1488#[5] *# @int@ x1;
     1489#* [5]# @int@ x2;
     1490#[* [5] int]# f@( int p )@;
    15051491\end{cfa}
    15061492&
    1507 \begin{cfa}
    1508 ®int® ß*ß x1 ß[5]ß;
    1509 ®int® ß(*ßx2ß)[5]ß;
    1510 ßint (*ßf®( int p )®ß)[5]ß;
     1493\begin{cfa}[moredelim={**[is][\color{blue}]{\#}{\#}}]
     1494@int@ #*# x1 #[5]#;
     1495@int@ #(*#x2#)[5]#;
     1496#int (*#f@( int p )@#)[5]#;
    15111497\end{cfa}
    15121498\end{tabular}
     
    15201506\multicolumn{1}{c@{\hspace{3em}}}{\textbf{\CFA}}        & \multicolumn{1}{c}{\textbf{C}}        \\
    15211507\begin{cfa}
    1522 ®*® int x, y;
     1508@*@ int x, y;
    15231509\end{cfa}
    15241510&
    15251511\begin{cfa}
    1526 int ®*®x, ®*®y;
     1512int @*@x, @*@y;
    15271513\end{cfa}
    15281514\end{tabular}
     
    15331519\multicolumn{1}{c@{\hspace{3em}}}{\textbf{\CFA}}        & \multicolumn{1}{c}{\textbf{C}}        \\
    15341520\begin{cfa}
    1535 ®*® int x;
     1521@*@ int x;
    15361522int y;
    15371523\end{cfa}
    15381524&
    15391525\begin{cfa}
    1540 int ®*®x, y;
     1526int @*@x, y;
    15411527
    15421528\end{cfa}
     
    16471633
    16481634\section{Pointer / Reference}
     1635\label{s:PointerReference}
    16491636
    16501637C provides a \newterm{pointer type};
     
    16731660&
    16741661\begin{cfa}
    1675 int * ®const® x = (int *)100
     1662int * @const@ x = (int *)100
    16761663*x = 3;                 // implicit dereference
    1677 int * ®const® y = (int *)104;
     1664int * @const@ y = (int *)104;
    16781665*y = *x;                        // implicit dereference
    16791666\end{cfa}
     
    17131700\begin{tabular}{@{}l@{\hspace{2em}}l@{}}
    17141701\begin{cfa}
    1715 int x, y, ®*® p1, ®*® p2, ®**® p3;
    1716 p1 = ®&®x;     // p1 points to x
     1702int x, y, @*@ p1, @*@ p2, @**@ p3;
     1703p1 = @&@x;     // p1 points to x
    17171704p2 = p1;     // p2 points to x
    1718 p1 = ®&®y;     // p1 points to y
     1705p1 = @&@y;     // p1 points to y
    17191706p3 = &p2;  // p3 points to p2
    17201707\end{cfa}
     
    17281715For example, \Index*{Algol68}~\cite{Algol68} infers pointer dereferencing to select the best meaning for each pointer usage
    17291716\begin{cfa}
    1730 p2 = p1 + x; §\C{// compiler infers *p2 = *p1 + x;}§
     1717p2 = p1 + x; $\C{// compiler infers *p2 = *p1 + x;}$
    17311718\end{cfa}
    17321719Algol68 infers the following dereferencing ©*p2 = *p1 + x©, because adding the arbitrary integer value in ©x© to the address of ©p1© and storing the resulting address into ©p2© is an unlikely operation.
     
    17361723In C, objects of pointer type always manipulate the pointer object's address:
    17371724\begin{cfa}
    1738 p1 = p2; §\C{// p1 = p2\ \ rather than\ \ *p1 = *p2}§
    1739 p2 = p1 + x; §\C{// p2 = p1 + x\ \ rather than\ \ *p2 = *p1 + x}§
     1725p1 = p2; $\C{// p1 = p2\ \ rather than\ \ *p1 = *p2}$
     1726p2 = p1 + x; $\C{// p2 = p1 + x\ \ rather than\ \ *p2 = *p1 + x}$
    17401727\end{cfa}
    17411728even though the assignment to ©p2© is likely incorrect, and the programmer probably meant:
    17421729\begin{cfa}
    1743 p1 = p2; §\C{// pointer address assignment}§
    1744 ®*®p2 = ®*®p1 + x; §\C{// pointed-to value assignment / operation}§
     1730p1 = p2; $\C{// pointer address assignment}$
     1731@*@p2 = @*@p1 + x; $\C{// pointed-to value assignment / operation}$
    17451732\end{cfa}
    17461733The C semantics work well for situations where manipulation of addresses is the primary meaning and data is rarely accessed, such as storage management (©malloc©/©free©).
     
    17581745To support this common case, a reference type is introduced in \CFA, denoted by ©&©, which is the opposite dereference semantics to a pointer type, making the value at the pointed-to location the implicit semantics for dereferencing (similar but not the same as \CC \Index{reference type}s).
    17591746\begin{cfa}
    1760 int x, y, ®&® r1, ®&® r2, ®&&® r3;
    1761 ®&®r1 = &x; §\C{// r1 points to x}§
    1762 ®&®r2 = &r1; §\C{// r2 points to x}§
    1763 ®&®r1 = &y; §\C{// r1 points to y}§
    1764 ®&&®r3 = ®&®&r2; §\C{// r3 points to r2}§
    1765 r2 = ((r1 + r2) * (r3 - r1)) / (r3 - 15); §\C{// implicit dereferencing}§
     1747int x, y, @&@ r1, @&@ r2, @&&@ r3;
     1748@&@r1 = &x; $\C{// r1 points to x}$
     1749@&@r2 = &r1; $\C{// r2 points to x}$
     1750@&@r1 = &y; $\C{// r1 points to y}$
     1751@&&@r3 = @&@&r2; $\C{// r3 points to r2}$
     1752r2 = ((r1 + r2) * (r3 - r1)) / (r3 - 15); $\C{// implicit dereferencing}$
    17661753\end{cfa}
    17671754Except for auto-dereferencing by the compiler, this reference example is the same as the previous pointer example.
     
    17691756One way to conceptualize a reference is via a rewrite rule, where the compiler inserts a dereference operator before the reference variable for each reference qualifier in a declaration, so the previous example becomes:
    17701757\begin{cfa}
    1771 ®*®r2 = ((®*®r1 + ®*®r2) ®*® (®**®r3 - ®*®r1)) / (®**®r3 - 15);
     1758@*@r2 = ((@*@r1 + @*@r2) @*@ (@**@r3 - @*@r1)) / (@**@r3 - 15);
    17721759\end{cfa}
    17731760When a reference operation appears beside a dereference operation, \eg ©&*©, they cancel out.
     
    17781765For a \CFA reference type, the cancellation on the left-hand side of assignment leaves the reference as an address (\Index{lvalue}):
    17791766\begin{cfa}
    1780 (&®*®)r1 = &x; §\C{// (\&*) cancel giving address in r1 not variable pointed-to by r1}§
     1767(&@*@)r1 = &x; $\C{// (\&*) cancel giving address in r1 not variable pointed-to by r1}$
    17811768\end{cfa}
    17821769Similarly, the address of a reference can be obtained for assignment or computation (\Index{rvalue}):
    17831770\begin{cfa}
    1784 (&(&®*®)®*®)r3 = &(&®*®)r2; §\C{// (\&*) cancel giving address in r2, (\&(\&*)*) cancel giving address in r3}§
     1771(&(&@*@)@*@)r3 = &(&@*@)r2; $\C{// (\&*) cancel giving address in r2, (\&(\&*)*) cancel giving address in r3}$
    17851772\end{cfa}
    17861773Cancellation\index{cancellation!pointer/reference}\index{pointer!cancellation} works to arbitrary depth.
     
    17901777int x, *p1 = &x, **p2 = &p1, ***p3 = &p2,
    17911778                 &r1 = x,    &&r2 = r1,   &&&r3 = r2;
    1792 ***p3 = 3; §\C{// change x}§
    1793 r3 = 3; §\C{// change x, ***r3}§
    1794 **p3 = ...; §\C{// change p1}§
    1795 &r3 = ...; §\C{// change r1, (\&*)**r3, 1 cancellation}§
    1796 *p3 = ...; §\C{// change p2}§
    1797 &&r3 = ...; §\C{// change r2, (\&(\&*)*)*r3, 2 cancellations}§
    1798 &&&r3 = p3; §\C{// change r3 to p3, (\&(\&(\&*)*)*)r3, 3 cancellations}§
     1779***p3 = 3; $\C{// change x}$
     1780r3 = 3; $\C{// change x, ***r3}$
     1781**p3 = ...; $\C{// change p1}$
     1782&r3 = ...; $\C{// change r1, (\&*)**r3, 1 cancellation}$
     1783*p3 = ...; $\C{// change p2}$
     1784&&r3 = ...; $\C{// change r2, (\&(\&*)*)*r3, 2 cancellations}$
     1785&&&r3 = p3; $\C{// change r3 to p3, (\&(\&(\&*)*)*)r3, 3 cancellations}$
    17991786\end{cfa}
    18001787Furthermore, both types are equally performant, as the same amount of dereferencing occurs for both types.
     
    18031790As for a pointer type, a reference type may have qualifiers:
    18041791\begin{cfa}
    1805 const int cx = 5; §\C{// cannot change cx;}§
    1806 const int & cr = cx; §\C{// cannot change what cr points to}§
    1807 ®&®cr = &cx; §\C{// can change cr}§
    1808 cr = 7; §\C{// error, cannot change cx}§
    1809 int & const rc = x; §\C{// must be initialized}§
    1810 ®&®rc = &x; §\C{// error, cannot change rc}§
    1811 const int & const crc = cx; §\C{// must be initialized}§
    1812 crc = 7; §\C{// error, cannot change cx}§
    1813 ®&®crc = &cx; §\C{// error, cannot change crc}§
     1792const int cx = 5; $\C{// cannot change cx;}$
     1793const int & cr = cx; $\C{// cannot change what cr points to}$
     1794@&@cr = &cx; $\C{// can change cr}$
     1795cr = 7; $\C{// error, cannot change cx}$
     1796int & const rc = x; $\C{// must be initialized}$
     1797@&@rc = &x; $\C{// error, cannot change rc}$
     1798const int & const crc = cx; $\C{// must be initialized}$
     1799crc = 7; $\C{// error, cannot change cx}$
     1800@&@crc = &cx; $\C{// error, cannot change crc}$
    18141801\end{cfa}
    18151802Hence, for type ©& const©, there is no pointer assignment, so ©&rc = &x© is disallowed, and \emph{the address value cannot be the null pointer unless an arbitrary pointer is coerced\index{coercion} into the reference}:
    18161803\begin{cfa}
    1817 int & const cr = *0; §\C{// where 0 is the int * zero}§
     1804int & const cr = *0; $\C{// where 0 is the int * zero}$
    18181805\end{cfa}
    18191806Note, constant reference-types do not prevent \Index{addressing errors} because of explicit storage-management:
     
    18221809cr = 5;
    18231810free( &cr );
    1824 cr = 7; §\C{// unsound pointer dereference}§
     1811cr = 7; $\C{// unsound pointer dereference}$
    18251812\end{cfa}
    18261813
    18271814The position of the ©const© qualifier \emph{after} the pointer/reference qualifier causes confuse for C programmers.
    18281815The ©const© qualifier cannot be moved before the pointer/reference qualifier for C style-declarations;
    1829 \CFA-style declarations (see \VRef{s:AlternativeDeclarations}) attempt to address this issue:
     1816\CFA-style declarations \see{\VRef{s:AlternativeDeclarations}} attempt to address this issue:
    18301817\begin{cquote}
    18311818\begin{tabular}{@{}l@{\hspace{3em}}l@{}}
    18321819\multicolumn{1}{c@{\hspace{3em}}}{\textbf{\CFA}}        & \multicolumn{1}{c}{\textbf{C}}        \\
    18331820\begin{cfa}
    1834 ®const® * ®const® * const int ccp;
    1835 ®const® & ®const® & const int ccr;
     1821@const@ * @const@ * const int ccp;
     1822@const@ & @const@ & const int ccr;
    18361823\end{cfa}
    18371824&
    18381825\begin{cfa}
    1839 const int * ®const® * ®const® ccp;
     1826const int * @const@ * @const@ ccp;
    18401827
    18411828\end{cfa}
     
    18461833Finally, like pointers, references are usable and composable with other type operators and generators.
    18471834\begin{cfa}
    1848 int w, x, y, z, & ar[3] = { x, y, z }; §\C{// initialize array of references}§
    1849 &ar[1] = &w; §\C{// change reference array element}§
    1850 typeof( ar[1] ) p; §\C{// (gcc) is int, \ie the type of referenced object}§
    1851 typeof( &ar[1] ) q; §\C{// (gcc) is int \&, \ie the type of reference}§
    1852 sizeof( ar[1] ) == sizeof( int ); §\C{// is true, \ie the size of referenced object}§
    1853 sizeof( &ar[1] ) == sizeof( int *) §\C{// is true, \ie the size of a reference}§
     1835int w, x, y, z, & ar[3] = { x, y, z }; $\C{// initialize array of references}$
     1836&ar[1] = &w; $\C{// change reference array element}$
     1837typeof( ar[1] ) p; $\C{// (gcc) is int, \ie the type of referenced object}$
     1838typeof( &ar[1] ) q; $\C{// (gcc) is int \&, \ie the type of reference}$
     1839sizeof( ar[1] ) == sizeof( int ); $\C{// is true, \ie the size of referenced object}$
     1840sizeof( &ar[1] ) == sizeof( int *) $\C{// is true, \ie the size of a reference}$
    18541841\end{cfa}
    18551842
    18561843In contrast to \CFA reference types, \Index*[C++]{\CC{}}'s reference types are all ©const© references, preventing changes to the reference address, so only value assignment is possible, which eliminates half of the \Index{address duality}.
    18571844Also, \CC does not allow \Index{array}s\index{array!reference} of reference\footnote{
    1858 The reason for disallowing arrays of reference is unknown, but possibly comes from references being ethereal (like a textual macro), and hence, replaceable by the referant object.}
     1845The reason for disallowing arrays of reference is unknown, but possibly comes from references being ethereal (like a textual macro), and hence, replaceable by the referent object.}
    18591846\Index*{Java}'s reference types to objects (all Java objects are on the heap) are like C pointers, which always manipulate the address, and there is no (bit-wise) object assignment, so objects are explicitly cloned by shallow or deep copying, which eliminates half of the address duality.
    18601847
     
    18681855Therefore, for pointer/reference initialization, the initializing value must be an address not a value.
    18691856\begin{cfa}
    1870 int * p = &x; §\C{// assign address of x}§
    1871 ®int * p = x;® §\C{// assign value of x}§
    1872 int & r = x; §\C{// must have address of x}§
     1857int * p = &x; $\C{// assign address of x}$
     1858@int * p = x;@ $\C{// assign value of x}$
     1859int & r = x; $\C{// must have address of x}$
    18731860\end{cfa}
    18741861Like the previous example with C pointer-arithmetic, it is unlikely assigning the value of ©x© into a pointer is meaningful (again, a warning is usually given).
     
    18791866Similarly, when a reference type is used for a parameter/return type, the call-site argument does not require a reference operator for the same reason.
    18801867\begin{cfa}
    1881 int & f( int & r ); §\C{// reference parameter and return}§
    1882 z = f( x ) + f( y ); §\C{// reference operator added, temporaries needed for call results}§
     1868int & f( int & r ); $\C{// reference parameter and return}$
     1869z = f( x ) + f( y ); $\C{// reference operator added, temporaries needed for call results}$
    18831870\end{cfa}
    18841871Within routine ©f©, it is possible to change the argument by changing the corresponding parameter, and parameter ©r© can be locally reassigned within ©f©.
     
    18931880When a pointer/reference parameter has a ©const© value (immutable), it is possible to pass literals and expressions.
    18941881\begin{cfa}
    1895 void f( ®const® int & cr );
    1896 void g( ®const® int * cp );
    1897 f( 3 );                   g( ®&®3 );
    1898 f( x + y );             g( ®&®(x + y) );
     1882void f( @const@ int & cr );
     1883void g( @const@ int * cp );
     1884f( 3 );                   g( @&@3 );
     1885f( x + y );             g( @&@(x + y) );
    18991886\end{cfa}
    19001887Here, the compiler passes the address to the literal 3 or the temporary for the expression ©x + y©, knowing the argument cannot be changed through the parameter.
     
    19071894void f( int & r );
    19081895void g( int * p );
    1909 f( 3 );                   g( ®&®3 ); §\C{// compiler implicit generates temporaries}§
    1910 f( x + y );             g( ®&®(x + y) ); §\C{// compiler implicit generates temporaries}§
     1896f( 3 );                   g( @&@3 ); $\C{// compiler implicit generates temporaries}$
     1897f( x + y );             g( @&@(x + y) ); $\C{// compiler implicit generates temporaries}$
    19111898\end{cfa}
    19121899Essentially, there is an implicit \Index{rvalue} to \Index{lvalue} conversion in this case.\footnote{
     
    19191906\begin{cfa}
    19201907void f( int i );
    1921 void (* fp)( int ); §\C{// routine pointer}§
    1922 fp = f; §\C{// reference initialization}§
    1923 fp = &f; §\C{// pointer initialization}§
    1924 fp = *f; §\C{// reference initialization}§
    1925 fp(3); §\C{// reference invocation}§
    1926 (*fp)(3); §\C{// pointer invocation}§
     1908void (* fp)( int ); $\C{// routine pointer}$
     1909fp = f; $\C{// reference initialization}$
     1910fp = &f; $\C{// pointer initialization}$
     1911fp = *f; $\C{// reference initialization}$
     1912fp(3); $\C{// reference invocation}$
     1913(*fp)(3); $\C{// pointer invocation}$
    19271914\end{cfa}
    19281915While C's treatment of routine objects has similarity to inferring a reference type in initialization contexts, the examples are assignment not initialization, and all possible forms of assignment are possible (©f©, ©&f©, ©*f©) without regard for type.
    19291916Instead, a routine object should be referenced by a ©const© reference:
    19301917\begin{cfa}
    1931 ®const® void (®&® fr)( int ) = f; §\C{// routine reference}§
    1932 fr = ... §\C{// error, cannot change code}§
    1933 &fr = ...; §\C{// changing routine reference}§
    1934 fr( 3 ); §\C{// reference call to f}§
    1935 (*fr)(3); §\C{// error, incorrect type}§
     1918@const@ void (@&@ fr)( int ) = f; $\C{// routine reference}$
     1919fr = ... $\C{// error, cannot change code}$
     1920&fr = ...; $\C{// changing routine reference}$
     1921fr( 3 ); $\C{// reference call to f}$
     1922(*fr)(3); $\C{// error, incorrect type}$
    19361923\end{cfa}
    19371924because the value of the routine object is a routine literal, \ie the routine code is normally immutable during execution.\footnote{
     
    19461933\begin{itemize}
    19471934\item
    1948 if ©R© is an \Index{rvalue} of type ©T &©$_1\cdots$ ©&©$_r$, where $r \ge 1$ references (©&© symbols), than ©&R© has type ©T ®*®&©$_{\color{red}2}\cdots$ ©&©$_{\color{red}r}$, \ie ©T© pointer with $r-1$ references (©&© symbols).
    1949 
    1950 \item
    1951 if ©L© is an \Index{lvalue} of type ©T &©$_1\cdots$ ©&©$_l$, where $l \ge 0$ references (©&© symbols), than ©&L© has type ©T ®*®&©$_{\color{red}1}\cdots$ ©&©$_{\color{red}l}$, \ie ©T© pointer with $l$ references (©&© symbols).
     1935if ©R© is an \Index{rvalue} of type ©T &©$_1\cdots$ ©&©$_r$, where $r \ge 1$ references (©&© symbols), than ©&R© has type ©T ©\R{©*©}©&©\R{$_2$}$\cdots$ ©&©\R{$_r$}, \ie ©T© pointer with $r-1$ references (©&© symbols).
     1936
     1937\item
     1938if ©L© is an \Index{lvalue} of type ©T &©$_1\cdots$ ©&©$_l$, where $l \ge 0$ references (©&© symbols), than ©&L© has type ©T ©\R{©*©}©&©\R{$_1$}$\cdots$ ©&©\R{$_l$}, \ie ©T© pointer with $l$ references (©&© symbols).
    19521939\end{itemize}
    19531940The following example shows the first rule applied to different \Index{rvalue} contexts:
     
    19551942int x, * px, ** ppx, *** pppx, **** ppppx;
    19561943int & rx = x, && rrx = rx, &&& rrrx = rrx ;
    1957 x = rrrx; §\C[2.0in]{// rrrx is an lvalue with type int \&\&\& (equivalent to x)}§
    1958 px = &rrrx; §\C{// starting from rrrx, \&rrrx is an rvalue with type int *\&\&\& (\&x)}§
    1959 ppx = &&rrrx; §\C{// starting from \&rrrx, \&\&rrrx is an rvalue with type int **\&\& (\&rx)}§
    1960 pppx = &&&rrrx; §\C{// starting from \&\&rrrx, \&\&\&rrrx is an rvalue with type int ***\& (\&rrx)}§
    1961 ppppx = &&&&rrrx; §\C{// starting from \&\&\&rrrx, \&\&\&\&rrrx is an rvalue with type int **** (\&rrrx)}§
     1944x = rrrx; $\C[2.0in]{// rrrx is an lvalue with type int \&\&\& (equivalent to x)}$
     1945px = &rrrx; $\C{// starting from rrrx, \&rrrx is an rvalue with type int *\&\&\& (\&x)}$
     1946ppx = &&rrrx; $\C{// starting from \&rrrx, \&\&rrrx is an rvalue with type int **\&\& (\&rx)}$
     1947pppx = &&&rrrx; $\C{// starting from \&\&rrrx, \&\&\&rrrx is an rvalue with type int ***\& (\&rrx)}$
     1948ppppx = &&&&rrrx; $\C{// starting from \&\&\&rrrx, \&\&\&\&rrrx is an rvalue with type int **** (\&rrrx)}$
    19621949\end{cfa}
    19631950The following example shows the second rule applied to different \Index{lvalue} contexts:
     
    19651952int x, * px, ** ppx, *** pppx;
    19661953int & rx = x, && rrx = rx, &&& rrrx = rrx ;
    1967 rrrx = 2; §\C{// rrrx is an lvalue with type int \&\&\& (equivalent to x)}§
    1968 &rrrx = px; §\C{// starting from rrrx, \&rrrx is an rvalue with type int *\&\&\& (rx)}§
    1969 &&rrrx = ppx; §\C{// starting from \&rrrx, \&\&rrrx is an rvalue with type int **\&\& (rrx)}§
    1970 &&&rrrx = pppx; §\C{// starting from \&\&rrrx, \&\&\&rrrx is an rvalue with type int ***\& (rrrx)}\CRT§
     1954rrrx = 2; $\C{// rrrx is an lvalue with type int \&\&\& (equivalent to x)}$
     1955&rrrx = px; $\C{// starting from rrrx, \&rrrx is an rvalue with type int *\&\&\& (rx)}$
     1956&&rrrx = ppx; $\C{// starting from \&rrrx, \&\&rrrx is an rvalue with type int **\&\& (rrx)}$
     1957&&&rrrx = pppx; $\C{// starting from \&\&rrrx, \&\&\&rrrx is an rvalue with type int ***\& (rrrx)}\CRT$
    19711958\end{cfa}
    19721959
     
    19811968\begin{cfa}
    19821969int x;
    1983 x + 1; §\C[2.0in]{// lvalue variable (int) converts to rvalue for expression}§
     1970x + 1; $\C[2.0in]{// lvalue variable (int) converts to rvalue for expression}$
    19841971\end{cfa}
    19851972An rvalue has no type qualifiers (©cv©), so the lvalue qualifiers are dropped.
     
    19911978\begin{cfa}
    19921979int x, &r = x, f( int p );
    1993 x = ®r® + f( ®r® ); §\C{// lvalue reference converts to rvalue}§
     1980x = @r@ + f( @r@ ); $\C{// lvalue reference converts to rvalue}$
    19941981\end{cfa}
    19951982An rvalue has no type qualifiers (©cv©), so the reference qualifiers are dropped.
     
    19981985lvalue to reference conversion: \lstinline[deletekeywords=lvalue]@lvalue-type cv1 T@ converts to ©cv2 T &©, which allows implicitly converting variables to references.
    19991986\begin{cfa}
    2000 int x, &r = ®x®, f( int & p ); §\C{// lvalue variable (int) convert to reference (int \&)}§
    2001 f( ®x® ); §\C{// lvalue variable (int) convert to reference (int \&)}§
     1987int x, &r = @x@, f( int & p ); $\C{// lvalue variable (int) convert to reference (int \&)}$
     1988f( @x@ ); $\C{// lvalue variable (int) convert to reference (int \&)}$
    20021989\end{cfa}
    20031990Conversion can restrict a type, where ©cv1© $\le$ ©cv2©, \eg passing an ©int© to a ©const volatile int &©, which has low cost.
     
    20091996\begin{cfa}
    20101997int x, & f( int & p );
    2011 f( ®x + 3® );   §\C[1.5in]{// rvalue parameter (int) implicitly converts to lvalue temporary reference (int \&)}§
    2012 ®&f®(...) = &x; §\C{// rvalue result (int \&) implicitly converts to lvalue temporary reference (int \&)}\CRT§
     1998f( @x + 3@ );   $\C[1.5in]{// rvalue parameter (int) implicitly converts to lvalue temporary reference (int \&)}$
     1999@&f@(...) = &x; $\C{// rvalue result (int \&) implicitly converts to lvalue temporary reference (int \&)}\CRT$
    20132000\end{cfa}
    20142001In both case, modifications to the temporary are inaccessible (\Index{warning}).
     
    21822169The point of the new syntax is to allow returning multiple values from a routine~\cite{Galletly96,CLU}, \eg:
    21832170\begin{cfa}
    2184 ®[ int o1, int o2, char o3 ]® f( int i1, char i2, char i3 ) {
    2185         §\emph{routine body}§
     2171@[ int o1, int o2, char o3 ]@ f( int i1, char i2, char i3 ) {
     2172        $\emph{routine body}$
    21862173}
    21872174\end{cfa}
     
    21942181Declaration qualifiers can only appear at the start of a routine definition, \eg:
    21952182\begin{cfa}
    2196 ®extern® [ int x ] g( int y ) {§\,§}
     2183@extern@ [ int x ] g( int y ) {$\,$}
    21972184\end{cfa}
    21982185Lastly, if there are no output parameters or input parameters, the brackets and/or parentheses must still be specified;
    21992186in both cases the type is assumed to be void as opposed to old style C defaults of int return type and unknown parameter types, respectively, as in:
    22002187\begin{cfa}
    2201 [§\,§] g(); §\C{// no input or output parameters}§
    2202 [ void ] g( void ); §\C{// no input or output parameters}§
     2188[$\,$] g(); $\C{// no input or output parameters}$
     2189[ void ] g( void ); $\C{// no input or output parameters}$
    22032190\end{cfa}
    22042191
     
    22182205\begin{cfa}
    22192206typedef int foo;
    2220 int f( int (* foo) ); §\C{// foo is redefined as a parameter name}§
     2207int f( int (* foo) ); $\C{// foo is redefined as a parameter name}$
    22212208\end{cfa}
    22222209The string ``©int (* foo)©'' declares a C-style named-parameter of type pointer to an integer (the parenthesis are superfluous), while the same string declares a \CFA style unnamed parameter of type routine returning integer with unnamed parameter of type pointer to foo.
     
    22262213C-style declarations can be used to declare parameters for \CFA style routine definitions, \eg:
    22272214\begin{cfa}
    2228 [ int ] f( * int, int * ); §\C{// returns an integer, accepts 2 pointers to integers}§
    2229 [ * int, int * ] f( int ); §\C{// returns 2 pointers to integers, accepts an integer}§
     2215[ int ] f( * int, int * ); $\C{// returns an integer, accepts 2 pointers to integers}$
     2216[ * int, int * ] f( int ); $\C{// returns 2 pointers to integers, accepts an integer}$
    22302217\end{cfa}
    22312218The reason for allowing both declaration styles in the new context is for backwards compatibility with existing preprocessor macros that generate C-style declaration-syntax, as in:
    22322219\begin{cfa}
    22332220#define ptoa( n, d ) int (*n)[ d ]
    2234 int f( ptoa( p, 5 ) ) ... §\C{// expands to int f( int (*p)[ 5 ] )}§
    2235 [ int ] f( ptoa( p, 5 ) ) ... §\C{// expands to [ int ] f( int (*p)[ 5 ] )}§
     2221int f( ptoa( p, 5 ) ) ... $\C{// expands to int f( int (*p)[ 5 ] )}$
     2222[ int ] f( ptoa( p, 5 ) ) ... $\C{// expands to [ int ] f( int (*p)[ 5 ] )}$
    22362223\end{cfa}
    22372224Again, programmers are highly encouraged to use one declaration form or the other, rather than mixing the forms.
     
    22522239\begin{minipage}{\linewidth}
    22532240\begin{cfa}
    2254 ®[ int x, int y ]® f() {
     2241@[ int x, int y ]@ f() {
    22552242        int z;
    22562243        ... x = 0; ... y = z; ...
    2257         ®return;® §\C{// implicitly return x, y}§
     2244        @return;@ $\C{// implicitly return x, y}$
    22582245}
    22592246\end{cfa}
     
    22652252[ int x, int y ] f() {
    22662253        ...
    2267 } §\C{// implicitly return x, y}§
     2254} $\C{// implicitly return x, y}$
    22682255\end{cfa}
    22692256In this case, the current values of ©x© and ©y© are returned to the calling routine just as if a ©return© had been encountered.
     
    22742261[ int x, int y ] f( int, x, int y ) {
    22752262        ...
    2276 } §\C{// implicitly return x, y}§
     2263} $\C{// implicitly return x, y}$
    22772264\end{cfa}
    22782265This notation allows the compiler to eliminate temporary variables in nested routine calls.
    22792266\begin{cfa}
    2280 [ int x, int y ] f( int, x, int y ); §\C{// prototype declaration}§
     2267[ int x, int y ] f( int, x, int y ); $\C{// prototype declaration}$
    22812268int a, b;
    22822269[a, b] = f( f( f( a, b ) ) );
     
    22922279as well, parameter names are optional, \eg:
    22932280\begin{cfa}
    2294 [ int x ] f (); §\C{// returning int with no parameters}§
    2295 [ * int ] g (int y); §\C{// returning pointer to int with int parameter}§
    2296 [ ] h ( int, char ); §\C{// returning no result with int and char parameters}§
    2297 [ * int, int ] j ( int ); §\C{// returning pointer to int and int, with int parameter}§
     2281[ int x ] f (); $\C{// returning int with no parameters}$
     2282[ * int ] g (int y); $\C{// returning pointer to int with int parameter}$
     2283[ ] h ( int, char ); $\C{// returning no result with int and char parameters}$
     2284[ * int, int ] j ( int ); $\C{// returning pointer to int and int, with int parameter}$
    22982285\end{cfa}
    22992286This syntax allows a prototype declaration to be created by cutting and pasting source text from the routine definition header (or vice versa).
    2300 Like C, it is possible to declare multiple routine-prototypes in a single declaration, where the return type is distributed across \emph{all} routine names in the declaration list (see~\VRef{s:AlternativeDeclarations}), \eg:
     2287Like C, it is possible to declare multiple routine-prototypes in a single declaration, where the return type is distributed across \emph{all} routine names in the declaration list \see{\VRef{s:AlternativeDeclarations}}, \eg:
    23012288\begin{cfa}
    23022289C :             const double bar1(), bar2( int ), bar3( double );
    2303 §\CFA§: [const double] foo(), foo( int ), foo( double ) { return 3.0; }
     2290$\CFA$: [const double] foo(), foo( int ), foo( double ) { return 3.0; }
    23042291\end{cfa}
    23052292\CFA allows the last routine in the list to define its body.
     
    23162303The syntax for pointers to \CFA routines specifies the pointer name on the right, \eg:
    23172304\begin{cfa}
    2318 * [ int x ] () fp; §\C{// pointer to routine returning int with no parameters}§
    2319 * [ * int ] (int y) gp; §\C{// pointer to routine returning pointer to int with int parameter}§
    2320 * [ ] (int,char) hp; §\C{// pointer to routine returning no result with int and char parameters}§
    2321 * [ * int,int ] ( int ) jp; §\C{// pointer to routine returning pointer to int and int, with int parameter}§
     2305* [ int x ] () fp; $\C[2.25in]{// pointer to routine returning int with no parameters}$
     2306* [ * int ] (int y) gp; $\C{// pointer to routine returning pointer to int with int parameter}$
     2307* [ ] (int,char) hp; $\C{// pointer to routine returning no result with int and char parameters}$
     2308* [ * int,int ] ( int ) jp; $\C{// pointer to routine returning pointer to int and int, with int parameter}\CRT$
    23222309\end{cfa}
    23232310While parameter names are optional, \emph{a routine name cannot be specified};
    23242311for example, the following is incorrect:
    23252312\begin{cfa}
    2326 * [ int x ] f () fp; §\C{// routine name "f" is not allowed}§
     2313* [ int x ] f () fp; $\C{// routine name "f" is not allowed}$
    23272314\end{cfa}
    23282315
     
    23472334whereas a named (keyword) call may be:
    23482335\begin{cfa}
    2349 p( z : 3, x : 4, y : 7 );  §\C{// rewrite $\Rightarrow$ p( 4, 7, 3 )}§
     2336p( z : 3, x : 4, y : 7 );  $\C{// rewrite \(\Rightarrow\) p( 4, 7, 3 )}$
    23502337\end{cfa}
    23512338Here the order of the arguments is unimportant, and the names of the parameters are used to associate argument values with the corresponding parameters.
     
    23642351For example, the following routine prototypes and definition are all valid.
    23652352\begin{cfa}
    2366 void p( int, int, int ); §\C{// equivalent prototypes}§
     2353void p( int, int, int ); $\C{// equivalent prototypes}$
    23672354void p( int x, int y, int z );
    23682355void p( int y, int x, int z );
    23692356void p( int z, int y, int x );
    2370 void p( int q, int r, int s ) {} §\C{// match with this definition}§
     2357void p( int q, int r, int s ) {} $\C{// match with this definition}$
    23712358\end{cfa}
    23722359Forcing matching parameter names in routine prototypes with corresponding routine definitions is possible, but goes against a strong tradition in C programming.
     
    23802367int f( int x, double y );
    23812368
    2382 f( j : 3, i : 4 ); §\C{// 1st f}§
    2383 f( x : 7, y : 8.1 ); §\C{// 2nd f}§
    2384 f( 4, 5 );  §\C{// ambiguous call}§
     2369f( j : 3, i : 4 ); $\C{// 1st f}$
     2370f( x : 7, y : 8.1 ); $\C{// 2nd f}$
     2371f( 4, 5 );  $\C{// ambiguous call}$
    23852372\end{cfa}
    23862373However, named arguments compound routine resolution in conjunction with conversions:
    23872374\begin{cfa}
    2388 f( i : 3, 5.7 ); §\C{// ambiguous call ?}§
     2375f( i : 3, 5.7 ); $\C{// ambiguous call ?}$
    23892376\end{cfa}
    23902377Depending on the cost associated with named arguments, this call could be resolvable or ambiguous.
     
    24002387the allowable positional calls are:
    24012388\begin{cfa}
    2402 p(); §\C{// rewrite $\Rightarrow$ p( 1, 2, 3 )}§
    2403 p( 4 ); §\C{// rewrite $\Rightarrow$ p( 4, 2, 3 )}§
    2404 p( 4, 4 ); §\C{// rewrite $\Rightarrow$ p( 4, 4, 3 )}§
    2405 p( 4, 4, 4 ); §\C{// rewrite $\Rightarrow$ p( 4, 4, 4 )}§
     2389p(); $\C{// rewrite \(\Rightarrow\) p( 1, 2, 3 )}$
     2390p( 4 ); $\C{// rewrite \(\Rightarrow\) p( 4, 2, 3 )}$
     2391p( 4, 4 ); $\C{// rewrite \(\Rightarrow\) p( 4, 4, 3 )}$
     2392p( 4, 4, 4 ); $\C{// rewrite \(\Rightarrow\) p( 4, 4, 4 )}$
    24062393// empty arguments
    2407 p(  , 4, 4 ); §\C{// rewrite $\Rightarrow$ p( 1, 4, 4 )}§
    2408 p( 4,  , 4 ); §\C{// rewrite $\Rightarrow$ p( 4, 2, 4 )}§
    2409 p( 4, 4,   ); §\C{// rewrite $\Rightarrow$ p( 4, 4, 3 )}§
    2410 p( 4,  ,   ); §\C{// rewrite $\Rightarrow$ p( 4, 2, 3 )}§
    2411 p(  , 4,   ); §\C{// rewrite $\Rightarrow$ p( 1, 4, 3 )}§
    2412 p(  ,  , 4 ); §\C{// rewrite $\Rightarrow$ p( 1, 2, 4 )}§
    2413 p(  ,  ,   ); §\C{// rewrite $\Rightarrow$ p( 1, 2, 3 )}§
     2394p(  , 4, 4 ); $\C{// rewrite \(\Rightarrow\) p( 1, 4, 4 )}$
     2395p( 4,  , 4 ); $\C{// rewrite \(\Rightarrow\) p( 4, 2, 4 )}$
     2396p( 4, 4,   ); $\C{// rewrite \(\Rightarrow\) p( 4, 4, 3 )}$
     2397p( 4,  ,   ); $\C{// rewrite \(\Rightarrow\) p( 4, 2, 3 )}$
     2398p(  , 4,   ); $\C{// rewrite \(\Rightarrow\) p( 1, 4, 3 )}$
     2399p(  ,  , 4 ); $\C{// rewrite \(\Rightarrow\) p( 1, 2, 4 )}$
     2400p(  ,  ,   ); $\C{// rewrite \(\Rightarrow\) p( 1, 2, 3 )}$
    24142401\end{cfa}
    24152402Here the missing arguments are inserted from the default values in the parameter list.
     
    24352422Default values may only appear in a prototype versus definition context:
    24362423\begin{cfa}
    2437 void p( int x, int y = 2, int z = 3 ); §\C{// prototype: allowed}§
    2438 void p( int, int = 2, int = 3 ); §\C{// prototype: allowed}§
    2439 void p( int x, int y = 2, int z = 3 ) {} §\C{// definition: not allowed}§
     2424void p( int x, int y = 2, int z = 3 ); $\C{// prototype: allowed}$
     2425void p( int, int = 2, int = 3 ); $\C{// prototype: allowed}$
     2426void p( int x, int y = 2, int z = 3 ) {} $\C{// definition: not allowed}$
    24402427\end{cfa}
    24412428The reason for this restriction is to allow separate compilation.
     
    24522439\begin{cfa}
    24532440p( int x, int y, int z, ... );
    2454 p( 1, 4, 5, 6, z : 3, y : 2 ); §\C{// assume p( /* positional */, ... , /* named */ );}§
    2455 p( 1, z : 3, y : 2, 4, 5, 6 ); §\C{// assume p( /* positional */, /* named */, ... );}§
     2441p( 1, 4, 5, 6, z : 3, y : 2 ); $\C{// assume p( /* positional */, ... , /* named */ );}$
     2442p( 1, z : 3, y : 2, 4, 5, 6 ); $\C{// assume p( /* positional */, /* named */, ... );}$
    24562443\end{cfa}
    24572444In the first call, it is necessary for the programmer to conceptually rewrite the call, changing named arguments into positional, before knowing where the ellipse arguments begin.
     
    24622449\begin{cfa}
    24632450void p( int x, int y = 2, int z = 3... );
    2464 p( 1, 4, 5, 6, z : 3 ); §\C{// assume p( /* positional */, ... , /* named */ );}§
    2465 p( 1, z : 3, 4, 5, 6 ); §\C{// assume p( /* positional */, /* named */, ... );}§
     2451p( 1, 4, 5, 6, z : 3 ); $\C{// assume p( /* positional */, ... , /* named */ );}$
     2452p( 1, z : 3, 4, 5, 6 ); $\C{// assume p( /* positional */, /* named */, ... );}$
    24662453\end{cfa}
    24672454The first call is an error because arguments 4 and 5 are actually positional not ellipse arguments;
     
    24692456In the second call, the default value for y is implicitly inserted after argument 1 and the named arguments separate the positional and ellipse arguments, making it trivial to read the call.
    24702457For these reasons, \CFA requires named arguments before ellipse arguments.
    2471 Finally, while ellipse arguments are needed for a small set of existing C routines, like printf, the extended \CFA type system largely eliminates the need for ellipse arguments (see Section 24), making much of this discussion moot.
    2472 
    2473 Default arguments and overloading (see Section 24) are complementary.
     2458Finally, while ellipse arguments are needed for a small set of existing C routines, like ©printf©, the extended \CFA type system largely eliminates the need for ellipse arguments \see{\VRef{s:Overloading}}, making much of this discussion moot.
     2459
     2460Default arguments and overloading \see{\VRef{s:Overloading}} are complementary.
    24742461While in theory default arguments can be simulated with overloading, as in:
    24752462\begin{cquote}
     
    24932480Furthermore, overloading cannot handle accessing default arguments in the middle of a positional list, via a missing argument, such as:
    24942481\begin{cfa}
    2495 p( 1, /* default */, 5 ); §\C{// rewrite $\Rightarrow$ p( 1, 2, 5 )}§
     2482p( 1, /* default */, 5 ); $\C{// rewrite \(\Rightarrow\) p( 1, 2, 5 )}$
    24962483\end{cfa}
    24972484
     
    25062493\begin{cfa}
    25072494struct {
    2508         int f1; §\C{// named field}§
    2509         int f2 : 4; §\C{// named field with bit field size}§
    2510         int : 3; §\C{// unnamed field for basic type with bit field size}§
    2511         int ; §\C{// disallowed, unnamed field}§
    2512         int *; §\C{// disallowed, unnamed field}§
    2513         int (*)( int ); §\C{// disallowed, unnamed field}§
     2495        int f1; $\C{// named field}$
     2496        int f2 : 4; $\C{// named field with bit field size}$
     2497        int : 3; $\C{// unnamed field for basic type with bit field size}$
     2498        int ; $\C{// disallowed, unnamed field}$
     2499        int *; $\C{// disallowed, unnamed field}$
     2500        int (*)( int ); $\C{// disallowed, unnamed field}$
    25142501};
    25152502\end{cfa}
     
    25192506\begin{cfa}
    25202507struct {
    2521         int , , ; §\C{// 3 unnamed fields}§
     2508        int , , ; $\C{// 3 unnamed fields}$
    25222509}
    25232510\end{cfa}
     
    25312518\subsection{Type Nesting}
    25322519
    2533 \CFA allows \Index{type nesting}, and type qualification of the nested types (see \VRef[Figure]{f:TypeNestingQualification}), where as C hoists\index{type hoisting} (refactors) nested types into the enclosing scope and has no type qualification.
     2520\CFA allows \Index{type nesting}, and type qualification of the nested types \see{\VRef[Figure]{f:TypeNestingQualification}}, where as C hoists\index{type hoisting} (refactors) nested types into the enclosing scope and has no type qualification.
    25342521\begin{figure}
    25352522\centering
     
    25872574
    25882575int fred() {
    2589         s.t.c = ®S.®R;  // type qualification
    2590         struct ®S.®T t = { ®S.®R, 1, 2 };
    2591         enum ®S.®C c;
    2592         union ®S.T.®U u;
     2576        s.t.c = @S.@R;  // type qualification
     2577        struct @S.@T t = { @S.@R, 1, 2 };
     2578        enum @S.@C c;
     2579        union @S.T.@U u;
    25932580}
    25942581\end{cfa}
     
    26132600const unsigned int size = 5;
    26142601int ia[size];
    2615 ... §\C{// assign values to array ia}§
    2616 qsort( ia, size ); §\C{// sort ascending order using builtin ?<?}§
     2602... $\C{// assign values to array ia}$
     2603qsort( ia, size ); $\C{// sort ascending order using builtin ?<?}$
    26172604{
    2618         ®int ?<?( int x, int y ) { return x > y; }® §\C{// nested routine}§
    2619         qsort( ia, size ); §\C{// sort descending order by local redefinition}§
     2605        @int ?<?( int x, int y ) { return x > y; }@ $\C{// nested routine}$
     2606        qsort( ia, size ); $\C{// sort descending order by local redefinition}$
    26202607}
    26212608\end{cfa}
     
    26252612The following program in undefined in \CFA (and Indexc{gcc})
    26262613\begin{cfa}
    2627 [* [int]( int )] foo() { §\C{// int (* foo())( int )}§
    2628         int ®i® = 7;
     2614[* [int]( int )] foo() { $\C{// int (* foo())( int )}$
     2615        int @i@ = 7;
    26292616        int bar( int p ) {
    2630                 ®i® += 1; §\C{// dependent on local variable}§
    2631                 sout | ®i®;
     2617                @i@ += 1; $\C{// dependent on local variable}$
     2618                sout | @i@;
    26322619        }
    2633         return bar; §\C{// undefined because of local dependence}§
     2620        return bar; $\C{// undefined because of local dependence}$
    26342621}
    26352622int main() {
    2636         * [int]( int ) fp = foo(); §\C{// int (* fp)( int )}§
     2623        * [int]( int ) fp = foo(); $\C{// int (* fp)( int )}$
    26372624        sout | fp( 3 );
    26382625}
     
    26472634In C and \CFA, lists of elements appear in several contexts, such as the parameter list of a routine call.
    26482635\begin{cfa}
    2649 f( ®2, x, 3 + i® ); §\C{// element list}§
     2636f( @2, x, 3 + i@ ); $\C{// element list}$
    26502637\end{cfa}
    26512638A list of elements is called a \newterm{tuple}, and is different from a \Index{comma expression}.
     
    26562643
    26572644In C and most programming languages, functions return at most one value;
    2658 however, many operations have multiple outcomes, some exceptional (see~\VRef{s:ExceptionHandling}).
     2645however, many operations have multiple outcomes, some exceptional \see{\VRef{s:ExceptionHandling}}.
    26592646To emulate functions with multiple return values, \emph{\Index{aggregation}} and/or \emph{\Index{aliasing}} is used.
    26602647
     
    26622649For example, consider C's \Indexc{div} function, which returns the quotient and remainder for a division of an integer value.
    26632650\begin{cfa}
    2664 typedef struct { int quot, rem; } div_t;        §\C[7cm]{// from include stdlib.h}§
     2651typedef struct { int quot, rem; } div_t;        $\C[7cm]{// from include stdlib.h}$
    26652652div_t div( int num, int den );
    2666 div_t qr = div( 13, 5 ); §\C{// return quotient/remainder aggregate}§
    2667 printf( "%d %d\n", qr.quot, qr.rem ); §\C{// print quotient/remainder}§
     2653div_t qr = div( 13, 5 ); $\C{// return quotient/remainder aggregate}$
     2654printf( "%d %d\n", qr.quot, qr.rem ); $\C{// print quotient/remainder}$
    26682655\end{cfa}
    26692656This approach requires a name for the return type and fields, where \Index{naming} is a common programming-language issue.
     
    26752662For example, consider C's \Indexc{modf} function, which returns the integral and fractional part of a floating value.
    26762663\begin{cfa}
    2677 double modf( double x, double * i ); §\C{// from include math.h}§
    2678 double intp, frac = modf( 13.5, &intp ); §\C{// return integral and fractional components}§
    2679 printf( "%g %g\n", intp, frac ); §\C{// print integral/fractional components}§
     2664double modf( double x, double * i ); $\C{// from include math.h}$
     2665double intp, frac = modf( 13.5, &intp ); $\C{// return integral and fractional components}$
     2666printf( "%g %g\n", intp, frac ); $\C{// print integral/fractional components}$
    26802667\end{cfa}
    26812668This approach requires allocating storage for the return values, which complicates the call site with a sequence of variable declarations leading to the call.
     
    27042691When a function call is passed as an argument to another call, the best match of actual arguments to formal parameters is evaluated given all possible expression interpretations in the current scope.
    27052692\begin{cfa}
    2706 void g( int, int ); §\C{// 1}§
    2707 void g( double, double ); §\C{// 2}§
    2708 g( div( 13, 5 ) ); §\C{// select 1}§
    2709 g( modf( 13.5 ) ); §\C{// select 2}§
     2693void g( int, int ); $\C{// 1}$
     2694void g( double, double ); $\C{// 2}$
     2695g( div( 13, 5 ) ); $\C{// select 1}$
     2696g( modf( 13.5 ) ); $\C{// select 2}$
    27102697\end{cfa}
    27112698In this case, there are two overloaded ©g© routines.
     
    27162703The previous examples can be rewritten passing the multiple returned-values directly to the ©printf© function call.
    27172704\begin{cfa}
    2718 [ int, int ] div( int x, int y ); §\C{// from include stdlib}§
    2719 printf( "%d %d\n", div( 13, 5 ) ); §\C{// print quotient/remainder}§
    2720 
    2721 [ double, double ] modf( double x ); §\C{// from include math}§
    2722 printf( "%g %g\n", modf( 13.5 ) ); §\C{// print integral/fractional components}§
     2705[ int, int ] div( int x, int y ); $\C{// from include stdlib}$
     2706printf( "%d %d\n", div( 13, 5 ) ); $\C{// print quotient/remainder}$
     2707
     2708[ double, double ] modf( double x ); $\C{// from include math}$
     2709printf( "%g %g\n", modf( 13.5 ) ); $\C{// print integral/fractional components}$
    27232710\end{cfa}
    27242711This approach provides the benefits of compile-time checking for appropriate return statements as in aggregation, but without the required verbosity of declaring a new named type.
     
    27302717\begin{cfa}
    27312718int quot, rem;
    2732 [ quot, rem ] = div( 13, 5 ); §\C{// assign multiple variables}§
    2733 printf( "%d %d\n", quot, rem ); §\C{// print quotient/remainder}\CRT§
     2719[ quot, rem ] = div( 13, 5 ); $\C{// assign multiple variables}$
     2720printf( "%d %d\n", quot, rem ); $\C{// print quotient/remainder}\CRT$
    27342721\end{cfa}
    27352722Here, the multiple return-values are matched in much the same way as passing multiple return-values to multiple parameters in a call.
     
    27602747In \CFA, it is possible to overcome this restriction by declaring a \newterm{tuple variable}.
    27612748\begin{cfa}
    2762 [int, int] ®qr® = div( 13, 5 ); §\C{// initialize tuple variable}§
    2763 printf( "%d %d\n", ®qr® ); §\C{// print quotient/remainder}§
     2749[int, int] @qr@ = div( 13, 5 ); $\C{// initialize tuple variable}$
     2750printf( "%d %d\n", @qr@ ); $\C{// print quotient/remainder}$
    27642751\end{cfa}
    27652752It is now possible to match the multiple return-values to a single variable, in much the same way as \Index{aggregation}.
     
    27672754One way to access the individual components of a tuple variable is with assignment.
    27682755\begin{cfa}
    2769 [ quot, rem ] = qr; §\C{// assign multiple variables}§
     2756[ quot, rem ] = qr; $\C{// assign multiple variables}$
    27702757\end{cfa}
    27712758
     
    27902777[int, double] * p;
    27912778
    2792 int y = x.0; §\C{// access int component of x}§
    2793 y = f().1; §\C{// access int component of f}§
    2794 p->0 = 5; §\C{// access int component of tuple pointed-to by p}§
    2795 g( x.1, x.0 ); §\C{// rearrange x to pass to g}§
    2796 double z = [ x, f() ].0.1; §\C{// access second component of first component of tuple expression}§
     2779int y = x.0; $\C{// access int component of x}$
     2780y = f().1; $\C{// access int component of f}$
     2781p->0 = 5; $\C{// access int component of tuple pointed-to by p}$
     2782g( x.1, x.0 ); $\C{// rearrange x to pass to g}$
     2783double z = [ x, f() ].0.1; $\C{// access second component of first component of tuple expression}$
    27972784\end{cfa}
    27982785Tuple-index expressions can occur on any tuple-typed expression, including tuple-returning functions, square-bracketed tuple expressions, and other tuple-index expressions, provided the retrieved component is also a tuple.
     
    28012788
    28022789\subsection{Flattening and Structuring}
     2790\label{s:FlatteningStructuring}
    28032791
    28042792As evident in previous examples, tuples in \CFA do not have a rigid structure.
     
    28612849double y;
    28622850[int, double] z;
    2863 [y, x] = 3.14; §\C{// mass assignment}§
    2864 [x, y] = z;                                                         §\C{// multiple assignment}§
    2865 z = 10;                                                         §\C{// mass assignment}§
    2866 z = [x, y]; §\C{// multiple assignment}§
     2851[y, x] = 3.14; $\C{// mass assignment}$
     2852[x, y] = z;                                                         $\C{// multiple assignment}$
     2853z = 10;                                                         $\C{// mass assignment}$
     2854z = [x, y]; $\C{// multiple assignment}$
    28672855\end{cfa}
    28682856Let $L_i$ for $i$ in $[0, n)$ represent each component of the flattened left side, $R_i$ represent each component of the flattened right side of a multiple assignment, and $R$ represent the right side of a mass assignment.
     
    28722860\begin{cfa}
    28732861[ int, int ] x, y, z;
    2874 [ x, y ] = z;                                              §\C{// multiple assignment, invalid 4 != 2}§
     2862[ x, y ] = z;                                              $\C{// multiple assignment, invalid 4 != 2}$
    28752863\end{cfa}
    28762864Multiple assignment assigns $R_i$ to $L_i$ for each $i$.
     
    29082896        double c, d;
    29092897        [ void ] f( [ int, int ] );
    2910         f( [ c, a ] = [ b, d ] = 1.5 ); §\C{// assignments in parameter list}§
     2898        f( [ c, a ] = [ b, d ] = 1.5 ); $\C{// assignments in parameter list}$
    29112899\end{cfa}
    29122900The tuple expression begins with a mass assignment of ©1.5© into ©[b, d]©, which assigns ©1.5© into ©b©, which is truncated to ©1©, and ©1.5© into ©d©, producing the tuple ©[1, 1.5]© as a result.
     
    29212909\begin{cfa}
    29222910struct S;
    2923 void ?{}(S *); §\C{// (1)}§
    2924 void ?{}(S *, int); §\C{// (2)}§
    2925 void ?{}(S * double); §\C{// (3)}§
    2926 void ?{}(S *, S); §\C{// (4)}§
    2927 
    2928 [S, S] x = [3, 6.28]; §\C{// uses (2), (3), specialized constructors}§
    2929 [S, S] y; §\C{// uses (1), (1), default constructor}§
    2930 [S, S] z = x.0; §\C{// uses (4), (4), copy constructor}§
     2911void ?{}(S *); $\C{// (1)}$
     2912void ?{}(S *, int); $\C{// (2)}$
     2913void ?{}(S * double); $\C{// (3)}$
     2914void ?{}(S *, S); $\C{// (4)}$
     2915
     2916[S, S] x = [3, 6.28]; $\C{// uses (2), (3), specialized constructors}$
     2917[S, S] y; $\C{// uses (1), (1), default constructor}$
     2918[S, S] z = x.0; $\C{// uses (4), (4), copy constructor}$
    29312919\end{cfa}
    29322920In this example, ©x© is initialized by the multiple constructor calls ©?{}(&x.0, 3)© and ©?{}(&x.1, 6.28)©, while ©y© is initialized by two default constructor calls ©?{}(&y.0)© and ©?{}(&y.1)©.
     
    29692957A member-access tuple may be used anywhere a tuple can be used, \eg:
    29702958\begin{cfa}
    2971 s.[ y, z, x ] = [ 3, 3.2, 'x' ]; §\C{// equivalent to s.x = 'x', s.y = 3, s.z = 3.2}§
    2972 f( s.[ y, z ] ); §\C{// equivalent to f( s.y, s.z )}§
     2959s.[ y, z, x ] = [ 3, 3.2, 'x' ]; $\C{// equivalent to s.x = 'x', s.y = 3, s.z = 3.2}$
     2960f( s.[ y, z ] ); $\C{// equivalent to f( s.y, s.z )}$
    29732961\end{cfa}
    29742962Note, the fields appearing in a record-field tuple may be specified in any order;
     
    29802968void f( double, long );
    29812969
    2982 f( x.[ 0, 3 ] ); §\C{// f( x.0, x.3 )}§
    2983 x.[ 0, 1 ] = x.[ 1, 0 ]; §\C{// [ x.0, x.1 ] = [ x.1, x.0 ]}§
     2970f( x.[ 0, 3 ] ); $\C{// f( x.0, x.3 )}$
     2971x.[ 0, 1 ] = x.[ 1, 0 ]; $\C{// [ x.0, x.1 ] = [ x.1, x.0 ]}$
    29842972[ long, int, long ] y = x.[ 2, 0, 2 ];
    29852973\end{cfa}
     
    29982986\begin{cfa}
    29992987[ int, float, double ] f();
    3000 [ double, float ] x = f().[ 2, 1 ]; §\C{// f() called once}§
     2988[ double, float ] x = f().[ 2, 1 ]; $\C{// f() called once}$
    30012989\end{cfa}
    30022990
     
    30112999That is, a cast can be used to select the type of an expression when it is ambiguous, as in the call to an overloaded function.
    30123000\begin{cfa}
    3013 int f(); §\C{// (1)}§
    3014 double f(); §\C{// (2)}§
    3015 
    3016 f(); §\C{// ambiguous - (1),(2) both equally viable}§
    3017 (int)f(); §\C{// choose (2)}§
     3001int f(); $\C{// (1)}$
     3002double f(); $\C{// (2)}$
     3003
     3004f(); $\C{// ambiguous - (1),(2) both equally viable}$
     3005(int)f(); $\C{// choose (2)}$
    30183006\end{cfa}
    30193007Since casting is a fundamental operation in \CFA, casts need to be given a meaningful interpretation in the context of tuples.
     
    30233011void g();
    30243012
    3025 (void)f(); §\C{// valid, ignore results}§
    3026 (int)g(); §\C{// invalid, void cannot be converted to int}§
     3013(void)f(); $\C{// valid, ignore results}$
     3014(int)g(); $\C{// invalid, void cannot be converted to int}$
    30273015
    30283016struct A { int x; };
    3029 (struct A)f(); §\C{// invalid, int cannot be converted to A}§
     3017(struct A)f(); $\C{// invalid, int cannot be converted to A}$
    30303018\end{cfa}
    30313019In C, line 4 is a valid cast, which calls ©f© and discards its result.
     
    30433031        [int, [int, int], int] g();
    30443032
    3045         ([int, double])f(); §\C{// (1) valid}§
    3046         ([int, int, int])g(); §\C{// (2) valid}§
    3047         ([void, [int, int]])g(); §\C{// (3) valid}§
    3048         ([int, int, int, int])g(); §\C{// (4) invalid}§
    3049         ([int, [int, int, int]])g(); §\C{// (5) invalid}§
     3033        ([int, double])f(); $\C{// (1) valid}$
     3034        ([int, int, int])g(); $\C{// (2) valid}$
     3035        ([void, [int, int]])g(); $\C{// (3) valid}$
     3036        ([int, int, int, int])g(); $\C{// (4) invalid}$
     3037        ([int, [int, int, int]])g(); $\C{// (5) invalid}$
    30503038\end{cfa}
    30513039
     
    31073095void f([int, int], int, int);
    31083096
    3109 f([0, 0], 0, 0); §\C{// no cost}§
    3110 f(0, 0, 0, 0); §\C{// cost for structuring}§
    3111 f([0, 0,], [0, 0]); §\C{// cost for flattening}§
    3112 f([0, 0, 0], 0); §\C{// cost for flattening and structuring}§
     3097f([0, 0], 0, 0); $\C{// no cost}$
     3098f(0, 0, 0, 0); $\C{// cost for structuring}$
     3099f([0, 0,], [0, 0]); $\C{// cost for flattening}$
     3100f([0, 0, 0], 0); $\C{// cost for flattening and structuring}$
    31133101\end{cfa}
    31143102
     
    31463134The general syntax of a lexical list is:
    31473135\begin{cfa}
    3148 [ §\emph{exprlist}§ ]
     3136[ $\emph{exprlist}$ ]
    31493137\end{cfa}
    31503138where ©$\emph{exprlist}$© is a list of one or more expressions separated by commas.
     
    31583146Tuples are permitted to contain sub-tuples (\ie nesting), such as ©[ [ 14, 21 ], 9 ]©, which is a 2-element tuple whose first element is itself a tuple.
    31593147Note, a tuple is not a record (structure);
    3160 a record denotes a single value with substructure, whereas a tuple is multiple values with no substructure (see flattening coercion in Section 12.1).
     3148a record denotes a single value with substructure, whereas a tuple is multiple values with no substructure \see{flattening coercion in \VRef{s:FlatteningStructuring}}.
    31613149In essence, tuples are largely a compile time phenomenon, having little or no runtime presence.
    31623150
     
    31663154The general syntax of a tuple type is:
    31673155\begin{cfa}
    3168 [ §\emph{typelist}§ ]
     3156[ $\emph{typelist}$ ]
    31693157\end{cfa}
    31703158where ©$\emph{typelist}$© is a list of one or more legal \CFA or C type specifications separated by commas, which may include other tuple type specifications.
     
    31733161[ unsigned int, char ]
    31743162[ double, double, double ]
    3175 [ * int, int * ] §\C{// mix of CFA and ANSI}§
     3163[ * int, int * ] $\C{// mix of CFA and ANSI}$
    31763164[ * [ 5 ] int, * * char, * [ [ int, int ] ] (int, int) ]
    31773165\end{cfa}
     
    31803168Examples of declarations using tuple types are:
    31813169\begin{cfa}
    3182 [ int, int ] x; §\C{// 2 element tuple, each element of type int}§
    3183 * [ char, char ] y; §\C{// pointer to a 2 element tuple}§
     3170[ int, int ] x; $\C{// 2 element tuple, each element of type int}$
     3171* [ char, char ] y; $\C{// pointer to a 2 element tuple}$
    31843172[ [ int, int ] ] z ([ int, int ]);
    31853173\end{cfa}
     
    31983186[ int, int ] w1;
    31993187[ int, int, int ] w2;
    3200 [ void ] f (int, int, int); §\C{// three input parameters of type int}§
    3201 [ void ] g ([ int, int, int ]); §\C{3 element tuple as input}§
     3188[ void ] f (int, int, int); $\C{// three input parameters of type int}$
     3189[ void ] g ([ int, int, int ]); $\C{3 element tuple as input}$
    32023190f( [ 1, 2, 3 ] );
    32033191f( w1, 3 );
     
    32793267[ int, int, int, int ] w = [ 1, 2, 3, 4 ];
    32803268int x = 5;
    3281 [ x, w ] = [ w, x ]; §\C{// all four tuple coercions}§
     3269[ x, w ] = [ w, x ]; $\C{// all four tuple coercions}$
    32823270\end{cfa}
    32833271Starting on the right-hand tuple in the last assignment statement, w is opened, producing a tuple of four values;
     
    32853273This tuple is then flattened, yielding ©[ 1, 2, 3, 4, 5 ]©, which is structured into ©[ 1, [ 2, 3, 4, 5 ] ]© to match the tuple type of the left-hand side.
    32863274The tuple ©[ 2, 3, 4, 5 ]© is then closed to create a tuple value.
    3287 Finally, ©x© is assigned ©1© and ©w© is assigned the tuple value using multiple assignment (see Section 14).
     3275Finally, ©x© is assigned ©1© and ©w© is assigned the tuple value using \Index{multiple assignment} \see{\VRef{s:TupleAssignment}}.
    32883276\begin{rationale}
    32893277A possible additional language extension is to use the structuring coercion for tuples to initialize a complex record with a tuple.
     
    32963284Mass assignment has the following form:
    32973285\begin{cfa}
    3298 [ §\emph{lvalue}§, ... , §\emph{lvalue}§ ] = §\emph{expr}§;
     3286[ $\emph{lvalue}$, ... , $\emph{lvalue}$ ] = $\emph{expr}$;
    32993287\end{cfa}
    33003288\index{lvalue}
     
    33363324Multiple assignment has the following form:
    33373325\begin{cfa}
    3338 [ §\emph{lvalue}§, ... , §\emph{lvalue}§ ] = [ §\emph{expr}§, ... , §\emph{expr}§ ];
     3326[ $\emph{lvalue}$, ... , $\emph{lvalue}$ ] = [ $\emph{expr}$, ... , $\emph{expr}$ ];
    33393327\end{cfa}
    33403328\index{lvalue}
     
    33673355both these examples produce indeterminate results:
    33683356\begin{cfa}
    3369 f( x++, x++ ); §\C{// C routine call with side effects in arguments}§
    3370 [ v1, v2 ] = [ x++, x++ ]; §\C{// side effects in righthand side of multiple assignment}§
     3357f( x++, x++ ); $\C{// C routine call with side effects in arguments}$
     3358[ v1, v2 ] = [ x++, x++ ]; $\C{// side effects in right-hand side of multiple assignment}$
    33713359\end{cfa}
    33723360
     
    33773365Cascade assignment has the following form:
    33783366\begin{cfa}
    3379 §\emph{tuple}§ = §\emph{tuple}§ = ... = §\emph{tuple}§;
     3367$\emph{tuple}$ = $\emph{tuple}$ = ... = $\emph{tuple}$;
    33803368\end{cfa}
    33813369and it has the same parallel semantics as for mass and multiple assignment.
     
    34243412\begin{cfa}
    34253413int x = 1, y = 2, z = 3;
    3426 sout | x ®|® y ®|® z;
     3414sout | x @|@ y @|@ z;
    34273415\end{cfa}
    34283416&
    34293417\begin{cfa}
    34303418
    3431 cout << x ®<< " "® << y ®<< " "® << z << endl;
     3419cout << x @<< " "@ << y @<< " "@ << z << endl;
    34323420\end{cfa}
    34333421&
     
    34383426\\
    34393427\begin{cfa}[showspaces=true,aboveskip=0pt,belowskip=0pt]
    3440 1® ®2® ®3
     34281@ @2@ @3
    34413429\end{cfa}
    34423430&
    34433431\begin{cfa}[showspaces=true,aboveskip=0pt,belowskip=0pt]
    3444 1® ®2® ®3
     34321@ @2@ @3
    34453433\end{cfa}
    34463434&
    34473435\begin{cfa}[showspaces=true,aboveskip=0pt,belowskip=0pt]
    3448 1® ®2® ®3
     34361@ @2@ @3
    34493437\end{cfa}
    34503438\end{tabular}
     
    34543442\begin{cfa}
    34553443[int, [ int, int ] ] t1 = [ 1, [ 2, 3 ] ], t2 = [ 4, [ 5, 6 ] ];
    3456 sout | t1 | t2; §\C{// print tuples}§
     3444sout | t1 | t2; $\C{// print tuples}$
    34573445\end{cfa}
    34583446\begin{cfa}[showspaces=true,aboveskip=0pt]
    3459 1®, ®2®, ®3 4®, ®5®, ®6
     34471@, @2@, @3 4@, @5@, @6
    34603448\end{cfa}
    34613449Finally, \CFA uses the logical-or operator for I/O as it is the lowest-priority \emph{overloadable} operator, other than assignment.
     
    34663454&
    34673455\begin{cfa}
    3468 sout | x * 3 | y + 1 | z << 2 | x == y | ®(®x | y®)® | ®(®x || y®)® | ®(®x > z ? 1 : 2®)®;
     3456sout | x * 3 | y + 1 | z << 2 | x == y | @(@x | y@)@ | @(@x || y@)@ | @(@x > z ? 1 : 2@)@;
    34693457\end{cfa}
    34703458\\
     
    34723460&
    34733461\begin{cfa}
    3474 cout << x * 3 << y + 1 << ®(®z << 2®)® << ®(®x == y®)® << ®(®x | y®)® << ®(®x || y®)® << ®(®x > z ? 1 : 2®)® << endl;
     3462cout << x * 3 << y + 1 << @(@z << 2@)@ << @(@x == y@)@ << @(@x | y@)@ << @(@x || y@)@ << @(@x > z ? 1 : 2@)@ << endl;
    34753463\end{cfa}
    34763464\\
     
    35073495\\
    35083496\begin{cfa}[showspaces=true,aboveskip=0pt,belowskip=0pt]
    3509 ®1® ®2.5® ®A®
     3497@1@ @2.5@ @A@
    35103498
    35113499
     
    35133501&
    35143502\begin{cfa}[showspaces=true,aboveskip=0pt,belowskip=0pt]
    3515 ®1® ®2.5® ®A®
     3503@1@ @2.5@ @A@
    35163504
    35173505
     
    35193507&
    35203508\begin{cfa}[showspaces=true,aboveskip=0pt,belowskip=0pt]
    3521 ®1®
    3522 ®2.5®
    3523 ®A®
     3509@1@
     3510@2.5@
     3511@A@
    35243512\end{cfa}
    35253513\end{tabular}
     
    35573545
    35583546\item
    3559 {\lstset{language=CFA,deletedelim=**[is][]{¢}{¢}}
    3560 A separator does not appear before a C string starting with the (extended) \Index*{ASCII}\index{ASCII!extended} characters: \lstinline[basicstyle=\tt]@,.;!?)]}%¢»@, where \lstinline[basicstyle=\tt]@»@ is a closing citation mark.
    3561 \begin{cfa}[belowskip=0pt]
     3547A separator does not appear before a C string starting with the (extended) \Index*{ASCII}\index{ASCII!extended} characters: \LstStringStyle{,.;!?)]\}\%\textcent\guillemotright}, where \LstStringStyle{\guillemotright} a closing citation mark.
     3548\begin{cfa}
    35623549sout | 1 | ", x" | 2 | ". x" | 3 | "; x" | 4 | "! x" | 5 | "? x" | 6 | "% x"
    3563                 | 7 | "¢ x" | 8 | "» x" | 9 | ") x" | 10 | "] x" | 11 | "} x";
    3564 \end{cfa}
    3565 \begin{cfa}[basicstyle=\tt,showspaces=true,aboveskip=0pt,belowskip=0pt]
    3566 1®,® x 2®.® x 3®;® x 4®!® x 5®?® x 6®%® x 7§\color{red}\textcent§ x 8®»® x 9®)® x 10®]® x 11®}® x
    3567 \end{cfa}}%
    3568 
    3569 \item
    3570 A separator does not appear after a C string ending with the (extended) \Index*{ASCII}\index{ASCII!extended} characters: \lstinline[mathescape=off,basicstyle=\tt]@([{=$£¥¡¿«@, where \lstinline[basicstyle=\tt]@¡¿@ are inverted opening exclamation and question marks, and \lstinline[basicstyle=\tt]@«@ is an opening citation mark.
     3550           | 7 | "$\LstStringStyle{\textcent}$ x" | 8 | "$\LstStringStyle{\guillemotright}$ x" | 9 | ") x" | 10 | "] x" | 11 | "} x";
     3551\end{cfa}
     3552\begin{cfa}[showspaces=true]
     35531@,@ x 2@.@ x 3@;@ x 4@!@ x 5@?@ x 6@%@ x 7$\R{\LstStringStyle{\textcent}}$ x 8$\R{\LstStringStyle{\guillemotright}}$ x 9@)@ x 10@]@ x 11@}@ x
     3554\end{cfa}
     3555
     3556\item
     3557A separator does not appear after a C string ending with the (extended) \Index*{ASCII}\index{ASCII!extended} characters: \LstStringStyle{([\{=\$\textsterling\textyen\textexclamdown\textquestiondown\guillemotleft}, where \LstStringStyle{\textexclamdown\textquestiondown} are inverted opening exclamation and question marks, and \LstStringStyle{\guillemotleft} is an opening citation mark.
    35713558%$
    3572 \begin{cfa}[mathescape=off]
    3573 sout | "x (" | 1 | "x [" | 2 | "x {" | 3 | "x =" | 4 | "x $" | 5 | "x £" | 6 | "x ¥"
    3574                 | 7 | "x ¡" | 8 | "x ¿" | 9 | "x «" | 10;
     3559\begin{cfa}
     3560sout | "x (" | 1 | "x [" | 2 | "x {" | 3 | "x =" | 4 | "x $" | 5 | "x $\LstStringStyle{\textsterling}$" | 6 | "x $\LstStringStyle{\textyen}$"
     3561           | 7 | "x $\LstStringStyle{\textexclamdown}$" | 8 | "x $\LstStringStyle{\textquestiondown}$" | 9 | "x $\LstStringStyle{\guillemotleft}$" | 10;
    35753562\end{cfa}
    35763563%$
    3577 \begin{cfa}[mathescape=off,basicstyle=\tt,showspaces=true,aboveskip=0pt,belowskip=0pt]
    3578 x ®(®1 x ®[®2 x ®{®3 x ®=®4 x ®$®5 x ®£®6 x ®¥®7 x ®¡®8 x ®¿®9 x ®«®10
     3564\begin{cfa}[showspaces=true]
     3565x @(@1 x @[@2 x @{@3 x @=@4 x $\LstStringStyle{\textdollar}$5 x $\R{\LstStringStyle{\textsterling}}$6 x $\R{\LstStringStyle{\textyen}}$7 x $\R{\LstStringStyle{\textexclamdown}}$8 x $\R{\LstStringStyle{\textquestiondown}}$9 x $\R{\LstStringStyle{\guillemotleft}}$10
    35793566\end{cfa}
    35803567%$
    35813568
    35823569\item
    3583 A seperator does not appear before/after a C string starting/ending with the \Index*{ASCII} quote or whitespace characters: \lstinline[basicstyle=\tt,showspaces=true]@`'": \t\v\f\r\n@
    3584 \begin{cfa}[belowskip=0pt]
     3570A seperator does not appear before/after a C string starting/ending with the \Index*{ASCII} quote or whitespace characters: \lstinline[basicstyle=\tt,showspaces=true]{`'": \t\v\f\r\n}
     3571\begin{cfa}
    35853572sout | "x`" | 1 | "`x'" | 2 | "'x\"" | 3 | "\"x:" | 4 | ":x " | 5 | " x\t" | 6 | "\tx";
    35863573\end{cfa}
    3587 \begin{cfa}[basicstyle=\tt,showspaces=true,showtabs=true,aboveskip=0pt,belowskip=0pt]
    3588 x®`®1®`®x§\color{red}\texttt{'}§2§\color{red}\texttt{'}§x§\color{red}\texttt{"}§3§\color{red}\texttt{"}§x®:®4®:®x® ®5® ®x®      ®6®     ®x
     3574\begin{cfa}[showspaces=true,showtabs=true]
     3575x@`@1@`@x$\R{\texttt{'}}$2$\R{\texttt{'}}$x$\R{\texttt{"}}$3$\R{\texttt{"}}$x@:@4@:@x@ @5@ @x@  @6@     @x
    35893576\end{cfa}
    35903577
    35913578\item
    35923579If a space is desired before or after one of the special string start/end characters, simply insert a space.
    3593 \begin{cfa}[belowskip=0pt]
    3594 sout | "x (§\color{red}\texttt{\textvisiblespace}§" | 1 | "§\color{red}\texttt{\textvisiblespace}§) x" | 2 | "§\color{red}\texttt{\textvisiblespace}§, x" | 3 | "§\color{red}\texttt{\textvisiblespace}§:x:§\color{red}\texttt{\textvisiblespace}§" | 4;
    3595 \end{cfa}
    3596 \begin{cfa}[basicstyle=\tt,showspaces=true,showtabs=true,aboveskip=0pt,belowskip=0pt]
    3597 x (® ®1® ®) x 2® ®, x 3® ®:x:® ®4
     3580\begin{cfa}
     3581sout | "x ($\R{\texttt{\textvisiblespace}}$" | 1 | "$\R{\texttt{\textvisiblespace}}$) x" | 2 | "$\R{\texttt{\textvisiblespace}}$, x" | 3 | "$\R{\texttt{\textvisiblespace}}$:x:$\R{\texttt{\textvisiblespace}}$" | 4;
     3582\end{cfa}
     3583\begin{cfa}[showspaces=true,showtabs=true]
     3584x (@ @1@ @) x 2@ @, x 3@ @:x:@ @4
    35983585\end{cfa}
    35993586\end{enumerate}
     
    36083595\Indexc{sepSet}\index{manipulator!sepSet@©sepSet©} and \Indexc{sep}\index{manipulator!sep@©sep©}/\Indexc{sepGet}\index{manipulator!sepGet@©sepGet©} set and get the separator string.
    36093596The separator string can be at most 16 characters including the ©'\0'© string terminator (15 printable characters).
    3610 \begin{cfa}[mathescape=off,belowskip=0pt]
    3611 sepSet( sout, ", $" ); §\C{// set separator from " " to ", \$"}§
    3612 sout | 1 | 2 | 3 | " \"" | ®sep® | "\"";
     3597\begin{cfa}[escapechar=off,belowskip=0pt]
     3598sepSet( sout, ", $" ); $\C{// set separator from " " to ", \$"}$
     3599sout | 1 | 2 | 3 | " \"" | @sep@ | "\"";
    36133600\end{cfa}
    36143601%$
    36153602\begin{cfa}[mathescape=off,showspaces=true,aboveskip=0pt]
    3616 1®, $®2®, $®3 ®", $"®
     36031@, $@2@, $@3 @", $"@
    36173604\end{cfa}
    36183605%$
    36193606\begin{cfa}[belowskip=0pt]
    3620 sepSet( sout, " " ); §\C{// reset separator to " "}§
    3621 sout | 1 | 2 | 3 | " \"" | ®sepGet( sout )® | "\"";
     3607sepSet( sout, " " ); $\C{// reset separator to " "}$
     3608sout | 1 | 2 | 3 | " \"" | @sepGet( sout )@ | "\"";
    36223609\end{cfa}
    36233610\begin{cfa}[showspaces=true,aboveskip=0pt]
    3624 1® ®2® ®3 ®" "®
     36111@ @2@ @3 @" "@
    36253612\end{cfa}
    36263613©sepGet© can be used to store a separator and then restore it:
    36273614\begin{cfa}[belowskip=0pt]
    3628 char store[®sepSize®]; §\C{// sepSize is the maximum separator size}§
    3629 strcpy( store, sepGet( sout ) ); §\C{// copy current separator}§
    3630 sepSet( sout, "_" ); §\C{// change separator to underscore}§
     3615char store[@sepSize@]; $\C{// sepSize is the maximum separator size}$
     3616strcpy( store, sepGet( sout ) ); $\C{// copy current separator}$
     3617sepSet( sout, "_" ); $\C{// change separator to underscore}$
    36313618sout | 1 | 2 | 3;
    36323619\end{cfa}
    36333620\begin{cfa}[showspaces=true,aboveskip=0pt,belowskip=0pt]
    3634 1®_®2®_®3
     36211@_@2@_@3
    36353622\end{cfa}
    36363623\begin{cfa}[belowskip=0pt]
    3637 sepSet( sout, store ); §\C{// change separator back to original}§
     3624sepSet( sout, store ); $\C{// change separator back to original}$
    36383625sout | 1 | 2 | 3;
    36393626\end{cfa}
    36403627\begin{cfa}[showspaces=true,aboveskip=0pt]
    3641 1® ®2® ®3
     36281@ @2@ @3
    36423629\end{cfa}
    36433630
     
    36463633The tuple separator-string can be at most 16 characters including the ©'\0'© string terminator (15 printable characters).
    36473634\begin{cfa}[belowskip=0pt]
    3648 sepSetTuple( sout, " " ); §\C{// set tuple separator from ", " to " "}§
    3649 sout | t1 | t2 | " \"" | ®sepTuple® | "\"";
     3635sepSetTuple( sout, " " ); $\C{// set tuple separator from ", " to " "}$
     3636sout | t1 | t2 | " \"" | @sepTuple@ | "\"";
    36503637\end{cfa}
    36513638\begin{cfa}[showspaces=true,aboveskip=0pt]
    3652 1 2 3 4 5 6 ®" "®
     36391 2 3 4 5 6 @" "@
    36533640\end{cfa}
    36543641\begin{cfa}[belowskip=0pt]
    3655 sepSetTuple( sout, ", " ); §\C{// reset tuple separator to ", "}§
    3656 sout | t1 | t2 | " \"" | ®sepGetTuple( sout )® | "\"";
     3642sepSetTuple( sout, ", " ); $\C{// reset tuple separator to ", "}$
     3643sout | t1 | t2 | " \"" | @sepGetTuple( sout )@ | "\"";
    36573644\end{cfa}
    36583645\begin{cfa}[showspaces=true,aboveskip=0pt]
    3659 1, 2, 3 4, 5, 6 ®", "®
     36461, 2, 3 4, 5, 6 @", "@
    36603647\end{cfa}
    36613648As for ©sepGet©, ©sepGetTuple© can be use to store a tuple separator and then restore it.
     
    36643651\Indexc{sepDisable}\index{manipulator!sepDisable@©sepDisable©} and \Indexc{sepEnable}\index{manipulator!sepEnable@©sepEnable©} toggle printing the separator.
    36653652\begin{cfa}[belowskip=0pt]
    3666 sout | sepDisable | 1 | 2 | 3; §\C{// turn off implicit separator}§
     3653sout | sepDisable | 1 | 2 | 3; $\C{// turn off implicit separator}$
    36673654\end{cfa}
    36683655\begin{cfa}[showspaces=true,aboveskip=0pt,belowskip=0pt]
     
    36703657\end{cfa}
    36713658\begin{cfa}[belowskip=0pt]
    3672 sout | sepEnable | 1 | 2 | 3; §\C{// turn on implicit separator}§
     3659sout | sepEnable | 1 | 2 | 3; $\C{// turn on implicit separator}$
    36733660\end{cfa}
    36743661\begin{cfa}[mathescape=off,showspaces=true,aboveskip=0pt,belowskip=0pt]
     
    36793666\Indexc{sepOn}\index{manipulator!sepOn@©sepOn©} and \Indexc{sepOff}\index{manipulator!sepOff@©sepOff©} toggle printing the separator with respect to the next printed item, and then return to the global seperator setting.
    36803667\begin{cfa}[belowskip=0pt]
    3681 sout | 1 | sepOff | 2 | 3; §\C{// turn off implicit separator for the next item}§
     3668sout | 1 | sepOff | 2 | 3; $\C{// turn off implicit separator for the next item}$
    36823669\end{cfa}
    36833670\begin{cfa}[showspaces=true,aboveskip=0pt,belowskip=0pt]
     
    36853672\end{cfa}
    36863673\begin{cfa}[belowskip=0pt]
    3687 sout | sepDisable | 1 | sepOn | 2 | 3; §\C{// turn on implicit separator for the next item}§
     3674sout | sepDisable | 1 | sepOn | 2 | 3; $\C{// turn on implicit separator for the next item}$
    36883675\end{cfa}
    36893676\begin{cfa}[showspaces=true,aboveskip=0pt,belowskip=0pt]
     
    36923679The tuple separator also responses to being turned on and off.
    36933680\begin{cfa}[belowskip=0pt]
    3694 sout | t1 | sepOff | t2; §\C{// turn off implicit separator for the next item}§
     3681sout | t1 | sepOff | t2; $\C{// turn off implicit separator for the next item}$
    36953682\end{cfa}
    36963683\begin{cfa}[showspaces=true,aboveskip=0pt,belowskip=0pt]
     
    37003687use ©sep© to accomplish this functionality.
    37013688\begin{cfa}[belowskip=0pt]
    3702 sout | sepOn | 1 | 2 | 3 | sepOn; §\C{// sepOn does nothing at start/end of line}§
     3689sout | sepOn | 1 | 2 | 3 | sepOn; $\C{// sepOn does nothing at start/end of line}$
    37033690\end{cfa}
    37043691\begin{cfa}[showspaces=true,aboveskip=0pt,belowskip=0pt]
     
    37063693\end{cfa}
    37073694\begin{cfa}[belowskip=0pt]
    3708 sout | sep | 1 | 2 | 3 | sep ; §\C{// use sep to print separator at start/end of line}§
     3695sout | sep | 1 | 2 | 3 | sep ; $\C{// use sep to print separator at start/end of line}$
    37093696\end{cfa}
    37103697\begin{cfa}[showspaces=true,aboveskip=0pt,belowskip=0pt]
    3711 ® ®1 2 3® ®
     3698@ @1 2 3@ @
    37123699\end{cfa}
    37133700\end{enumerate}
     
    37213708\begin{enumerate}[parsep=0pt]
    37223709\item
    3723 \Indexc{nl}\index{manipulator!nl@©nl©} scans characters until the next newline character, i.e., ignore the remaining characters in the line.
     3710\Indexc{nl}\index{manipulator!nl@©nl©} scans characters until the next newline character, \ie ignore the remaining characters in the line.
    37243711\item
    37253712\Indexc{nlOn}\index{manipulator!nlOn@©nlOn©} reads the newline character, when reading single characters.
     
    37293716For example, in:
    37303717\begin{cfa}
    3731 sin | i | ®nl® | j;
    3732 1 ®2®
     3718sin | i | @nl@ | j;
     37191 @2@
    373337203
    37343721\end{cfa}
     
    37403727\Indexc{nl}\index{manipulator!nl@©nl©} inserts a newline.
    37413728\begin{cfa}
    3742 sout | nl; §\C{// only print newline}§
    3743 sout | 2; §\C{// implicit newline}§
    3744 sout | 3 | nl | 4 | nl; §\C{// terminating nl merged with implicit newline}§
    3745 sout | 5 | nl | nl; §\C{// again terminating nl merged with implicit newline}§
    3746 sout | 6; §\C{// implicit newline}§
     3729sout | nl; $\C{// only print newline}$
     3730sout | 2; $\C{// implicit newline}$
     3731sout | 3 | nl | 4 | nl; $\C{// terminating nl merged with implicit newline}$
     3732sout | 5 | nl | nl; $\C{// again terminating nl merged with implicit newline}$
     3733sout | 6; $\C{// implicit newline}$
    37473734
    374837352
     
    377137580b0 0b11011 0b11011 0b11011 0b11011
    37723759sout | bin( -27HH ) | bin( -27H ) | bin( -27 ) | bin( -27L );
    3773 0b11100101 0b1111111111100101 0b11111111111111111111111111100101 0b®(58 1s)®100101
     37600b11100101 0b1111111111100101 0b11111111111111111111111111100101 0b@(58 1s)@100101
    37743761\end{cfa}
    37753762
     
    38103797\begin{cfa}[belowskip=0pt]
    38113798sout | upcase( bin( 27 ) ) | upcase( hex( 27 ) ) | upcase( 27.5e-10 ) | upcase( hex( 27.5 ) );
    3812 0®B®11011 0®X®1®B® 2.75®E®-09 0®X®1.®B®8®P®+4
     37990@B@11011 0@X@1@B@ 2.75@E@-09 0@X@1.@B@8@P@+4
    38133800\end{cfa}
    38143801
     
    38263813\begin{cfa}[belowskip=0pt]
    38273814sout | 0. | nodp( 0. ) | 27.0 | nodp( 27.0 ) | nodp( 27.5 );
    3828 0.0 ®0® 27.0 ®27® 27.5
     38150.0 @0@ 27.0 @27@ 27.5
    38293816\end{cfa}
    38303817
     
    38333820\begin{cfa}[belowskip=0pt]
    38343821sout | sign( 27 ) | sign( -27 ) | sign( 27. ) | sign( -27. ) | sign( 27.5 ) | sign( -27.5 );
    3835 ®+®27 -27 ®+®27.0 -27.0 ®+®27.5 -27.5
     3822@+@27 -27 @+@27.0 -27.0 @+@27.5 -27.5
    38363823\end{cfa}
    38373824
     
    38463833\end{cfa}
    38473834\begin{cfa}[showspaces=true,aboveskip=0pt,belowskip=0pt]
    3848 ®  ®34 ® ®34 34
    3849 ®  ®4.000000 ® ®4.000000 4.000000
    3850 ®  ®ab ® ®ab ab
     3835@  @34 @ @34 34
     3836@  @4.000000 @ @4.000000 4.000000
     3837@  @ab @ @ab ab
    38513838\end{cfa}
    38523839If the value is larger, it is printed without truncation, ignoring the ©minimum©.
     
    38573844\end{cfa}
    38583845\begin{cfa}[showspaces=true,aboveskip=0pt,belowskip=0pt]
    3859 3456®7® 345®67® 34®567®
    3860 3456®.® 345®6.® 34®56.®
    3861 abcd®e® abc®de® ab®cde®
     38463456@7@ 345@67@ 34@567@
     38473456@.@ 345@6.@ 34@56.@
     3848abcd@e@ abc@de@ ab@cde@
    38623849\end{cfa}
    38633850
     
    38683855\end{cfa}
    38693856\begin{cfa}[showspaces=true,aboveskip=0pt,belowskip=0pt]
    3870  ®0®34     ®00®34 ®00000000®34
     3857 @0@34     @00@34 @00000000@34
    38713858\end{cfa}
    38723859If the value is larger, it is printed without truncation, ignoring the ©precision©.
     
    38833870\end{cfa}
    38843871\begin{cfa}[showspaces=true,aboveskip=0pt,belowskip=0pt]
    3885 ®    ® ®00000000®34
     3872@    @ @00000000@34
    38863873\end{cfa}
    38873874For floating-point types, ©precision© is the minimum number of digits after the decimal point.
     
    38903877\end{cfa}
    38913878\begin{cfa}[showspaces=true,aboveskip=0pt,belowskip=0pt]
    3892 27.®500®     27.®5®      28. 27.®50000000®
    3893 \end{cfa}
    3894 For the C-string type, ©precision© is the maximum number of printed characters, so the string is truncared if it exceeds the maximum.
     387927.@500@     27.@5@      28. 27.@50000000@
     3880\end{cfa}
     3881For the C-string type, ©precision© is the maximum number of printed characters, so the string is truncated if it exceeds the maximum.
    38953882\begin{cfa}[belowskip=0pt]
    38963883sout | wd( 6,8, "abcd" ) | wd( 6,8, "abcdefghijk" ) | wd( 6,3, "abcd" );
     
    39083895\end{cfa}
    39093896\begin{cfa}[showspaces=true,aboveskip=0pt,belowskip=0pt]
    3910 234.567 234.5®7®  234.®6®    23®5®
     3897234.567 234.5@7@  234.@6@    23@5@
    39113898\end{cfa}
    39123899If a value's magnitude is greater than ©significant©, the value is printed in scientific notation with the specified number of significant digits.
     
    39153902\end{cfa}
    39163903\begin{cfa}[showspaces=true,aboveskip=0pt,belowskip=0pt]
    3917 234567. 2.3457®e+05® 2.346®e+05® 2.35®e+05®
     3904234567. 2.3457@e+05@ 2.346@e+05@ 2.35@e+05@
    39183905\end{cfa}
    39193906If ©significant© is greater than ©minimum©, it defines the number of printed characters.
     
    39313918\end{cfa}
    39323919\begin{cfa}[showspaces=true,aboveskip=0pt,belowskip=0pt]
    3933 27®  ® 27.000000  27.500000  027  27.500®    ®
     392027@  @ 27.000000  27.500000  027  27.500@    @
    39343921\end{cfa}
    39353922
     
    39383925\begin{cfa}[belowskip=0pt]
    39393926sout | pad0( wd( 4, 27 ) ) | pad0( wd( 4,3, 27 ) ) | pad0( wd( 8,3, 27.5 ) );
    3940 ®00®27  ®0®27 ®00®27.500
     3927@00@27  @0@27 @00@27.500
    39413928\end{cfa}
    39423929\end{enumerate}
     
    40344021\end{cfa}
    40354022\begin{cfa}[showspaces=true,aboveskip=0pt,belowskip=0pt]
    4036 ®abc   ®
    4037 ®abc  ®
    4038 ®xx®
     4023@abc   @
     4024@abc  @
     4025@xx@
    40394026\end{cfa}
    40404027
     
    40474034\end{cfa}
    40484035\begin{cfa}[showspaces=true,aboveskip=0pt,belowskip=0pt]
    4049 ®abcd1233.456E+2®
     4036@abcd1233.456E+2@
    40504037\end{cfa}
    40514038Note, input ©wdi© cannot be overloaded with output ©wd© because both have the same parameters but return different types.
     
    40604047\end{cfa}
    40614048\begin{cfa}[showspaces=true,aboveskip=0pt,belowskip=0pt]
    4062 ®  -75.35e-4® 25
     4049@  -75.35e-4@ 25
    40634050\end{cfa}
    40644051
     
    40724059\end{cfa}
    40734060\begin{cfa}[showspaces=true,aboveskip=0pt,belowskip=0pt]
    4074 ®bca®xyz
     4061@bca@xyz
    40754062\end{cfa}
    40764063
     
    40844071\end{cfa}
    40854072\begin{cfa}[showspaces=true,aboveskip=0pt,belowskip=0pt]
    4086 ®xyz®bca
     4073@xyz@bca
    40874074\end{cfa}
    40884075\end{enumerate}
     
    41014088
    41024089A type definition is different from a typedef in C because a typedef just creates an alias for a type,  while Do.s type definition creates a distinct type.
    4103 This means that users can define distinct function overloads for the new type (see Overloading for more information).
     4090This means that users can define distinct function overloads for the new type \see{\VRef{s:Overloading} for more information}.
    41044091For example:
    41054092
     
    42074194\CFA supports C initialization of structures, but it also adds constructors for more advanced initialization.
    42084195Additionally, \CFA adds destructors that are called when a variable is deallocated (variable goes out of scope or object is deleted).
    4209 These functions take a reference to the structure as a parameter (see References for more information).
     4196These functions take a reference to the structure as a parameter \see{\VRef{s:PointerReference} for more information}.
    42104197
    42114198\begin{figure}
     
    42584245
    42594246\section{Overloading}
     4247\label{s:Overloading}
    42604248
    42614249Overloading refers to the capability of a programmer to define and use multiple objects in a program with the same name.
     
    42904278
    42914279
    4292 \subsection{Overloaded Constant}
     4280\subsection{Constant}
    42934281
    42944282The constants 0 and 1 have special meaning.
     
    43294317
    43304318
    4331 \subsection{Variable Overloading}
     4319\subsection{Variable}
     4320\label{s:VariableOverload}
    43324321
    43334322The overload rules of \CFA allow a programmer to define multiple variables with the same name, but different types.
     
    43724361
    43734362
    4374 \subsection{Operator Overloading}
     4363\subsection{Operator}
    43754364
    43764365\CFA also allows operators to be overloaded, to simplify the use of user-defined types.
     
    44684457For example, given
    44694458\begin{cfa}
    4470 auto j = ®...®
     4459auto j = @...@
    44714460\end{cfa}
    44724461and the need to write a routine to compute using ©j©
    44734462\begin{cfa}
    4474 void rtn( ®...® parm );
     4463void rtn( @...@ parm );
    44754464rtn( j );
    44764465\end{cfa}
     
    47134702
    47144703coroutine Fibonacci {
    4715         int fn; §\C{// used for communication}§
     4704        int fn; $\C{// used for communication}$
    47164705};
    47174706void ?{}( Fibonacci * this ) {
     
    47194708}
    47204709void main( Fibonacci * this ) {
    4721         int fn1, fn2; §\C{// retained between resumes}§
    4722         this->fn = 0; §\C{// case 0}§
     4710        int fn1, fn2; $\C{// retained between resumes}$
     4711        this->fn = 0; $\C{// case 0}$
    47234712        fn1 = this->fn;
    4724         suspend(); §\C{// return to last resume}§
    4725 
    4726         this->fn = 1; §\C{// case 1}§
     4713        suspend(); $\C{// return to last resume}$
     4714
     4715        this->fn = 1; $\C{// case 1}$
    47274716        fn2 = fn1;
    47284717        fn1 = this->fn;
    4729         suspend(); §\C{// return to last resume}§
    4730 
    4731         for ( ;; ) { §\C{// general case}§
     4718        suspend(); $\C{// return to last resume}$
     4719
     4720        for ( ;; ) { $\C{// general case}$
    47324721                this->fn = fn1 + fn2;
    47334722                fn2 = fn1;
    47344723                fn1 = this->fn;
    4735                 suspend(); §\C{// return to last resume}§
     4724                suspend(); $\C{// return to last resume}$
    47364725        } // for
    47374726}
    47384727int next( Fibonacci * this ) {
    4739         resume( this ); §\C{// transfer to last suspend}§
     4728        resume( this ); $\C{// transfer to last suspend}$
    47404729        return this->fn;
    47414730}
     
    49644953When building a \CFA module which needs to be callable from C code, users can use the tools to generate a header file suitable for including in these C files with all of the needed declarations.
    49654954
    4966 In order to interoperate with existing C code, \CFA files can still include header files, the contents of which will be enclosed in a C linkage section to indicate C calling conventions (see Interoperability for more information).
     4955In order to interoperate with existing C code, \CFA files can still include header files, the contents of which will be enclosed in a C linkage section to indicate C calling conventions \see{\VRef{s:Interoperability} for more information}.
    49674956
    49684957
     
    56305619\end{cfa}
    56315620&
    5632 \begin{lstlisting}[language=C++]
     5621\begin{C++}
    56335622class Line {
    56345623        float lnth;
     
    56575646Line line1;
    56585647Line line2( 3.4 );
    5659 \end{lstlisting}
     5648\end{C++}
    56605649&
    56615650\begin{lstlisting}[language=Golang]
     
    62826271In \CFA, there are ambiguous cases with dereference and operator identifiers, \eg ©int *?*?()©, where the string ©*?*?© can be interpreted as:
    62836272\begin{cfa}
    6284 *?§\color{red}\textvisiblespace§*? §\C{// dereference operator, dereference operator}§
    6285 *§\color{red}\textvisiblespace§?*? §\C{// dereference, multiplication operator}§
     6273*?$\R{\textvisiblespace}$*? $\C{// dereference operator, dereference operator}$
     6274*$\R{\textvisiblespace}$?*? $\C{// dereference, multiplication operator}$
    62866275\end{cfa}
    62876276By default, the first interpretation is selected, which does not yield a meaningful parse.
     
    62926281The ambiguity occurs when the deference operator has no parameters:
    62936282\begin{cfa}
    6294 *?()§\color{red}\textvisiblespace...§ ;
    6295 *?()§\color{red}\textvisiblespace...§(...) ;
     6283*?()$\R{\textvisiblespace...}$ ;
     6284*?()$\R{\textvisiblespace...}$(...) ;
    62966285\end{cfa}
    62976286requiring arbitrary whitespace look-ahead for the routine-call parameter-list to disambiguate.
     
    63016290The remaining cases are with the increment/decrement operators and conditional expression, \eg:
    63026291\begin{cfa}
    6303 i++?§\color{red}\textvisiblespace...§(...);
    6304 i?++§\color{red}\textvisiblespace...§(...);
     6292i++?$\R{\textvisiblespace...}$(...);
     6293i?++$\R{\textvisiblespace...}$(...);
    63056294\end{cfa}
    63066295requiring arbitrary whitespace look-ahead for the operator parameter-list, even though that interpretation is an incorrect expression (juxtaposed identifiers).
    63076296Therefore, it is necessary to disambiguate these cases with a space:
    63086297\begin{cfa}
    6309 i++§\color{red}\textvisiblespace§? i : 0;
    6310 i?§\color{red}\textvisiblespace§++i : 0;
     6298i++$\R{\textvisiblespace}$? i : 0;
     6299i?$\R{\textvisiblespace}$++i : 0;
    63116300\end{cfa}
    63126301
     
    63216310\begin{description}
    63226311\item[Change:] add new keywords \\
    6323 New keywords are added to \CFA (see~\VRef{s:CFAKeywords}).
     6312New keywords are added to \CFA \see{\VRef{s:CFAKeywords}}.
    63246313\item[Rationale:] keywords added to implement new semantics of \CFA.
    63256314\item[Effect on original feature:] change to semantics of well-defined feature. \\
    63266315Any \Celeven programs using these keywords as identifiers are invalid \CFA programs.
    6327 \item[Difficulty of converting:] keyword clashes are accommodated by syntactic transformations using the \CFA backquote escape-mechanism (see~\VRef{s:BackquoteIdentifiers}).
     6316\item[Difficulty of converting:] keyword clashes are accommodated by syntactic transformations using the \CFA backquote escape-mechanism \see{\VRef{s:BackquoteIdentifiers}}.
    63286317\item[How widely used:] clashes among new \CFA keywords and existing identifiers are rare.
    63296318\end{description}
     
    63356324\eg:
    63366325\begin{cfa}
    6337 x; §\C{// int x}§
    6338 *y; §\C{// int *y}§
    6339 f( p1, p2 ); §\C{// int f( int p1, int p2 );}§
    6340 g( p1, p2 ) int p1, p2; §\C{// int g( int p1, int p2 );}§
     6326x; $\C{// int x}$
     6327*y; $\C{// int *y}$
     6328f( p1, p2 ); $\C{// int f( int p1, int p2 );}$
     6329g( p1, p2 ) int p1, p2; $\C{// int g( int p1, int p2 );}$
    63416330\end{cfa}
    63426331\CFA continues to support K\&R routine definitions:
    63436332\begin{cfa}
    6344 f( a, b, c ) §\C{// default int return}§
    6345         int a, b; char c §\C{// K\&R parameter declarations}§
     6333f( a, b, c ) $\C{// default int return}$
     6334        int a, b; char c $\C{// K\&R parameter declarations}$
    63466335{
    63476336        ...
     
    63626351int rtn( int i );
    63636352int rtn( char c );
    6364 rtn( 'x' ); §\C{// programmer expects 2nd rtn to be called}§
     6353rtn( 'x' ); $\C{// programmer expects 2nd rtn to be called}$
    63656354\end{cfa}
    63666355\item[Rationale:] it is more intuitive for the call to ©rtn© to match the second version of definition of ©rtn© rather than the first.
     
    63846373\item[Change:] make string literals ©const©:
    63856374\begin{cfa}
    6386 char * p = "abc"; §\C{// valid in C, deprecated in \CFA}§
    6387 char * q = expr ? "abc" : "de"; §\C{// valid in C, invalid in \CFA}§
     6375char * p = "abc"; $\C{// valid in C, deprecated in \CFA}$
     6376char * q = expr ? "abc" : "de"; $\C{// valid in C, invalid in \CFA}$
    63886377\end{cfa}
    63896378The type of a string literal is changed from ©[] char© to ©const [] char©.
     
    63926381\begin{cfa}
    63936382char * p = "abc";
    6394 p[0] = 'w'; §\C{// segment fault or change constant literal}§
     6383p[0] = 'w'; $\C{// segment fault or change constant literal}$
    63956384\end{cfa}
    63966385The same problem occurs when passing a string literal to a routine that changes its argument.
     
    64046393\item[Change:] remove \newterm{tentative definitions}, which only occurs at file scope:
    64056394\begin{cfa}
    6406 int i; §\C{// forward definition}§
    6407 int *j = ®&i®; §\C{// forward reference, valid in C, invalid in \CFA}§
    6408 int i = 0; §\C{// definition}§
     6395int i; $\C{// forward definition}$
     6396int *j = @&i@; $\C{// forward reference, valid in C, invalid in \CFA}$
     6397int i = 0; $\C{// definition}$
    64096398\end{cfa}
    64106399is valid in C, and invalid in \CFA because duplicate overloaded object definitions at the same scope level are disallowed.
     
    64126401\begin{cfa}
    64136402struct X { int i; struct X *next; };
    6414 static struct X a; §\C{// forward definition}§
    6415 static struct X b = { 0, ®&a® };§\C{// forward reference, valid in C, invalid in \CFA}§
    6416 static struct X a = { 1, &b }; §\C{// definition}§
     6403static struct X a; $\C{// forward definition}$
     6404static struct X b = { 0, @&a@ };$\C{// forward reference, valid in C, invalid in \CFA}$
     6405static struct X a = { 1, &b }; $\C{// definition}$
    64176406\end{cfa}
    64186407\item[Rationale:] avoids having different initialization rules for builtin types and user-defined types.
     
    64266415\item[Change:] have ©struct© introduce a scope for nested types:
    64276416\begin{cfa}
    6428 enum ®Colour® { R, G, B, Y, C, M };
     6417enum @Colour@ { R, G, B, Y, C, M };
    64296418struct Person {
    6430         enum ®Colour® { R, G, B };      §\C[7cm]{// nested type}§
    6431         struct Face { §\C{// nested type}§
    6432                 ®Colour® Eyes, Hair; §\C{// type defined outside (1 level)}§
     6419        enum @Colour@ { R, G, B };      $\C[7cm]{// nested type}$
     6420        struct Face { $\C{// nested type}$
     6421                @Colour@ Eyes, Hair; $\C{// type defined outside (1 level)}$
    64336422        };
    6434         ®.Colour® shirt; §\C{// type defined outside (top level)}§
    6435         ®Colour® pants; §\C{// type defined same level}§
    6436         Face looks[10]; §\C{// type defined same level}§
     6423        @.Colour@ shirt; $\C{// type defined outside (top level)}$
     6424        @Colour@ pants; $\C{// type defined same level}$
     6425        Face looks[10]; $\C{// type defined same level}$
    64376426};
    6438 ®Colour® c = R; §\C{// type/enum defined same level}§
    6439 Person®.Colour® pc = Person®.®R;§\C{// type/enum defined inside}§
    6440 Person®.®Face pretty; §\C{// type defined inside}\CRT§
     6427@Colour@ c = R; $\C{// type/enum defined same level}$
     6428Person@.Colour@ pc = Person@.@R;$\C{// type/enum defined inside}$
     6429Person@.@Face pretty; $\C{// type defined inside}\CRT$
    64416430\end{cfa}
    64426431In C, the name of the nested types belongs to the same scope as the name of the outermost enclosing structure, \ie the nested types are hoisted to the scope of the outer-most type, which is not useful and confusing.
     
    64556444\item[Difficulty of converting:] Semantic transformation. To make the struct type name visible in the scope of the enclosing struct, the struct tag could be declared in the scope of the enclosing struct, before the enclosing struct is defined. Example:
    64566445\begin{cfa}
    6457 struct Y; §\C{// struct Y and struct X are at the same scope}§
     6446struct Y; $\C{// struct Y and struct X are at the same scope}$
    64586447struct X {
    64596448        struct Y { /* ... */ } y;
     
    64706459\begin{cfa}
    64716460void foo() {
    6472         int * b = malloc( sizeof(int) ); §\C{// implicitly convert void * to int *}§
    6473         char * c = b; §\C{// implicitly convert int * to void *, and then void * to char *}§
     6461        int * b = malloc( sizeof(int) ); $\C{// implicitly convert void * to int *}$
     6462        char * c = b; $\C{// implicitly convert int * to void *, and then void * to char *}$
    64746463}
    64756464\end{cfa}
    64766465\item[Rationale:] increase type safety
    64776466\item[Effect on original feature:] deletion of semantically well-defined feature.
    6478 \item[Difficulty of converting:] requires adding a cast (see \VRef{s:StorageManagement} for better alternatives):
     6467\item[Difficulty of converting:] requires adding a cast \see{\VRef{s:StorageManagement} for better alternatives}:
    64796468\begin{cfa}
    64806469        int * b = (int *)malloc( sizeof(int) );
     
    65866575\end{cquote}
    65876576For the prescribed head-files, \CFA uses header interposition to wraps these includes in an ©extern "C"©;
    6588 hence, names in these include files are not mangled\index{mangling!name} (see~\VRef{s:Interoperability}).
     6577hence, names in these include files are not mangled\index{mangling!name} \see{\VRef{s:Interoperability}}.
    65896578All other C header files must be explicitly wrapped in ©extern "C"© to prevent name mangling.
    65906579This approach is different from \Index*[C++]{\CC{}} where the name-mangling issue is handled internally in C header-files through checks for preprocessor variable ©__cplusplus©, which adds appropriate ©extern "C"© qualifiers.
     
    66496638Type-safe allocation is provided for all C allocation routines and new \CFA allocation routines, \eg in
    66506639\begin{cfa}
    6651 int * ip = (int *)malloc( sizeof(int) );                §\C{// C}§
    6652 int * ip = malloc();                                                    §\C{// \CFA type-safe version of C malloc}§
    6653 int * ip = alloc();                                                             §\C{// \CFA type-safe uniform alloc}§
     6640int * ip = (int *)malloc( sizeof(int) );                $\C{// C}$
     6641int * ip = malloc();                                                    $\C{// \CFA type-safe version of C malloc}$
     6642int * ip = alloc();                                                             $\C{// \CFA type-safe uniform alloc}$
    66546643\end{cfa}
    66556644the latter two allocations determine the allocation size from the type of ©p© (©int©) and cast the pointer to the allocated storage to ©int *©.
     
    66586647\begin{cfa}
    66596648struct S { int i; } __attribute__(( aligned( 128 ) )); // cache-line alignment
    6660 S * sp = malloc();                                                              §\C{// honour type alignment}§
     6649S * sp = malloc();                                                              $\C{// honour type alignment}$
    66616650\end{cfa}
    66626651the storage allocation is implicitly aligned to 128 rather than the default 16.
     
    66736662\CFA memory management extends allocation to support constructors for initialization of allocated storage, \eg in
    66746663\begin{cfa}
    6675 struct S { int i; };                                                    §\C{// cache-line aglinment}§
     6664struct S { int i; };                                                    $\C{// cache-line alignment}$
    66766665void ?{}( S & s, int i ) { s.i = i; }
    66776666// assume ?|? operator for printing an S
    66786667
    6679 S & sp = *®new®( 3 );                                                   §\C{// call constructor after allocation}§
     6668S & sp = *@new@( 3 );                                                   $\C{// call constructor after allocation}$
    66806669sout | sp.i;
    6681 ®delete®( &sp );
    6682 
    6683 S * spa = ®anew®( 10, 5 );                                              §\C{// allocate array and initialize each array element}§
     6670@delete@( &sp );
     6671
     6672S * spa = @anew@( 10, 5 );                                              $\C{// allocate array and initialize each array element}$
    66846673for ( i; 10 ) sout | spa[i] | nonl;
    66856674sout | nl;
    6686 ®adelete®( 10, spa );
     6675@adelete@( 10, spa );
    66876676\end{cfa}
    66886677Allocation routines ©new©/©anew© allocate a variable/array and initialize storage using the allocated type's constructor.
     
    66936682extern "C" {
    66946683        // C unsafe allocation
    6695         void * malloc( size_t size );§\indexc{malloc}§
    6696         void * calloc( size_t dim, size_t size );§\indexc{calloc}§
    6697         void * realloc( void * ptr, size_t size );§\indexc{realloc}§
    6698         void * memalign( size_t align, size_t size );§\indexc{memalign}§
    6699         void * aligned_alloc( size_t align, size_t size );§\indexc{aligned_alloc}§
    6700         int posix_memalign( void ** ptr, size_t align, size_t size );§\indexc{posix_memalign}§
    6701         void * cmemalign( size_t alignment, size_t noOfElems, size_t elemSize );§\indexc{cmemalign}§ // CFA
     6684        void * malloc( size_t size );$\indexc{malloc}$
     6685        void * calloc( size_t dim, size_t size );$\indexc{calloc}$
     6686        void * realloc( void * ptr, size_t size );$\indexc{realloc}$
     6687        void * memalign( size_t align, size_t size );$\indexc{memalign}$
     6688        void * aligned_alloc( size_t align, size_t size );$\indexc{aligned_alloc}$
     6689        int posix_memalign( void ** ptr, size_t align, size_t size );$\indexc{posix_memalign}$
     6690        void * cmemalign( size_t alignment, size_t noOfElems, size_t elemSize );$\indexc{cmemalign}$ // CFA
    67026691
    67036692        // C unsafe initialization/copy
    6704         void * memset( void * dest, int c, size_t size );§\indexc{memset}§
    6705         void * memcpy( void * dest, const void * src, size_t size );§\indexc{memcpy}§
     6693        void * memset( void * dest, int c, size_t size );$\indexc{memset}$
     6694        void * memcpy( void * dest, const void * src, size_t size );$\indexc{memcpy}$
    67066695}
    67076696
     
    67096698
    67106699forall( dtype T | sized(T) ) {
    6711         // §\CFA§ safe equivalents, i.e., implicit size specification
     6700        // $\CFA$ safe equivalents, i.e., implicit size specification
    67126701        T * malloc( void );
    67136702        T * calloc( size_t dim );
     
    67186707        int posix_memalign( T ** ptr, size_t align );
    67196708
    6720         // §\CFA§ safe general allocation, fill, resize, alignment, array
    6721         T * alloc( void );§\indexc{alloc}§                                      §\C[3.5in]{// variable, T size}§
    6722         T * alloc( size_t dim );                                                        §\C{// array[dim], T size elements}§
    6723         T * alloc( T ptr[], size_t dim );                                       §\C{// realloc array[dim], T size elements}§
    6724 
    6725         T * alloc_set( char fill );§\indexc{alloc_set}§         §\C{// variable, T size, fill bytes with value}§
    6726         T * alloc_set( T fill );                                                        §\C{// variable, T size, fill with value}§
    6727         T * alloc_set( size_t dim, char fill );                         §\C{// array[dim], T size elements, fill bytes with value}§
    6728         T * alloc_set( size_t dim, T fill );                            §\C{// array[dim], T size elements, fill elements with value}§
    6729         T * alloc_set( size_t dim, const T fill[] );            §\C{// array[dim], T size elements, fill elements with array}§
    6730         T * alloc_set( T ptr[], size_t dim, char fill );        §\C{// realloc array[dim], T size elements, fill bytes with value}§
    6731 
    6732         T * alloc_align( size_t align );                                        §\C{// aligned variable, T size}§
    6733         T * alloc_align( size_t align, size_t dim );            §\C{// aligned array[dim], T size elements}§
    6734         T * alloc_align( T ptr[], size_t align );                       §\C{// realloc new aligned array}§
    6735         T * alloc_align( T ptr[], size_t align, size_t dim ); §\C{// realloc new aligned array[dim]}§
    6736 
    6737         T * alloc_align_set( size_t align, char fill );         §\C{// aligned variable, T size, fill bytes with value}§
    6738         T * alloc_align_set( size_t align, T fill );            §\C{// aligned variable, T size, fill with value}§
    6739         T * alloc_align_set( size_t align, size_t dim, char fill ); §\C{// aligned array[dim], T size elements, fill bytes with value}§
    6740         T * alloc_align_set( size_t align, size_t dim, T fill ); §\C{// aligned array[dim], T size elements, fill elements with value}§
    6741         T * alloc_align_set( size_t align, size_t dim, const T fill[] ); §\C{// aligned array[dim], T size elements, fill elements with array}§
    6742         T * alloc_align_set( T ptr[], size_t align, size_t dim, char fill ); §\C{// realloc new aligned array[dim], fill new bytes with value}§
    6743 
    6744         // §\CFA§ safe initialization/copy, i.e., implicit size specification
    6745         T * memset( T * dest, char fill );§\indexc{memset}§
    6746         T * memcpy( T * dest, const T * src );§\indexc{memcpy}§
    6747 
    6748         // §\CFA§ safe initialization/copy, i.e., implicit size specification, array types
     6709        // $\CFA$ safe general allocation, fill, resize, alignment, array
     6710        T * alloc( void );$\indexc{alloc}$                                      $\C[3.5in]{// variable, T size}$
     6711        T * alloc( size_t dim );                                                        $\C{// array[dim], T size elements}$
     6712        T * alloc( T ptr[], size_t dim );                                       $\C{// realloc array[dim], T size elements}$
     6713
     6714        T * alloc_set( char fill );$\indexc{alloc_set}$         $\C{// variable, T size, fill bytes with value}$
     6715        T * alloc_set( T fill );                                                        $\C{// variable, T size, fill with value}$
     6716        T * alloc_set( size_t dim, char fill );                         $\C{// array[dim], T size elements, fill bytes with value}$
     6717        T * alloc_set( size_t dim, T fill );                            $\C{// array[dim], T size elements, fill elements with value}$
     6718        T * alloc_set( size_t dim, const T fill[] );            $\C{// array[dim], T size elements, fill elements with array}$
     6719        T * alloc_set( T ptr[], size_t dim, char fill );        $\C{// realloc array[dim], T size elements, fill bytes with value}$
     6720
     6721        T * alloc_align( size_t align );                                        $\C{// aligned variable, T size}$
     6722        T * alloc_align( size_t align, size_t dim );            $\C{// aligned array[dim], T size elements}$
     6723        T * alloc_align( T ptr[], size_t align );                       $\C{// realloc new aligned array}$
     6724        T * alloc_align( T ptr[], size_t align, size_t dim ); $\C{// realloc new aligned array[dim]}$
     6725
     6726        T * alloc_align_set( size_t align, char fill );         $\C{// aligned variable, T size, fill bytes with value}$
     6727        T * alloc_align_set( size_t align, T fill );            $\C{// aligned variable, T size, fill with value}$
     6728        T * alloc_align_set( size_t align, size_t dim, char fill ); $\C{// aligned array[dim], T size elements, fill bytes with value}$
     6729        T * alloc_align_set( size_t align, size_t dim, T fill ); $\C{// aligned array[dim], T size elements, fill elements with value}$
     6730        T * alloc_align_set( size_t align, size_t dim, const T fill[] ); $\C{// aligned array[dim], T size elements, fill elements with array}$
     6731        T * alloc_align_set( T ptr[], size_t align, size_t dim, char fill ); $\C{// realloc new aligned array[dim], fill new bytes with value}$
     6732
     6733        // $\CFA$ safe initialization/copy, i.e., implicit size specification
     6734        T * memset( T * dest, char fill );$\indexc{memset}$
     6735        T * memcpy( T * dest, const T * src );$\indexc{memcpy}$
     6736
     6737        // $\CFA$ safe initialization/copy, i.e., implicit size specification, array types
    67496738        T * amemset( T dest[], char fill, size_t dim );
    67506739        T * amemcpy( T dest[], const T src[], size_t dim );
    67516740}
    67526741
    6753 // §\CFA§ allocation/deallocation and constructor/destructor, non-array types
    6754 forall( dtype T | sized(T), ttype Params | { void ?{}( T &, Params ); } ) T * new( Params p );§\indexc{new}§
    6755 forall( dtype T | sized(T) | { void ^?{}( T & ); } ) void delete( T * ptr );§\indexc{delete}§
     6742// $\CFA$ allocation/deallocation and constructor/destructor, non-array types
     6743forall( dtype T | sized(T), ttype Params | { void ?{}( T &, Params ); } ) T * new( Params p );$\indexc{new}$
     6744forall( dtype T | sized(T) | { void ^?{}( T & ); } ) void delete( T * ptr );$\indexc{delete}$
    67566745forall( dtype T, ttype Params | sized(T) | { void ^?{}( T & ); void delete( Params ); } )
    67576746  void delete( T * ptr, Params rest );
    67586747
    6759 // §\CFA§ allocation/deallocation and constructor/destructor, array types
    6760 forall( dtype T | sized(T), ttype Params | { void ?{}( T &, Params ); } ) T * anew( size_t dim, Params p );§\indexc{anew}§
    6761 forall( dtype T | sized(T) | { void ^?{}( T & ); } ) void adelete( size_t dim, T arr[] );§\indexc{adelete}§
     6748// $\CFA$ allocation/deallocation and constructor/destructor, array types
     6749forall( dtype T | sized(T), ttype Params | { void ?{}( T &, Params ); } ) T * anew( size_t dim, Params p );$\indexc{anew}$
     6750forall( dtype T | sized(T) | { void ^?{}( T & ); } ) void adelete( size_t dim, T arr[] );$\indexc{adelete}$
    67626751forall( dtype T | sized(T) | { void ^?{}( T & ); }, ttype Params | { void adelete( Params ); } )
    67636752  void adelete( size_t dim, T arr[], Params rest );
     
    67696758\leavevmode
    67706759\begin{cfa}[aboveskip=0pt,belowskip=0pt]
    6771 int ato( const char * ptr );§\indexc{ato}§
     6760int ato( const char * ptr );$\indexc{ato}$
    67726761unsigned int ato( const char * ptr );
    67736762long int ato( const char * ptr );
     
    68016790\leavevmode
    68026791\begin{cfa}[aboveskip=0pt,belowskip=0pt]
    6803 forall( otype T | { int ?<?( T, T ); } ) §\C{// location}§
    6804 T * bsearch( T key, const T * arr, size_t dim );§\indexc{bsearch}§
    6805 
    6806 forall( otype T | { int ?<?( T, T ); } ) §\C{// position}§
     6792forall( otype T | { int ?<?( T, T ); } ) $\C{// location}$
     6793T * bsearch( T key, const T * arr, size_t dim );$\indexc{bsearch}$
     6794
     6795forall( otype T | { int ?<?( T, T ); } ) $\C{// position}$
    68076796unsigned int bsearch( T key, const T * arr, size_t dim );
    68086797
    68096798forall( otype T | { int ?<?( T, T ); } )
    6810 void qsort( const T * arr, size_t dim );§\indexc{qsort}§
     6799void qsort( const T * arr, size_t dim );$\indexc{qsort}$
    68116800
    68126801forall( otype E | { int ?<?( E, E ); } ) {
    6813         E * bsearch( E key, const E * vals, size_t dim );§\indexc{bsearch}§ §\C{// location}§
    6814         size_t bsearch( E key, const E * vals, size_t dim );§\C{// position}§
    6815         E * bsearchl( E key, const E * vals, size_t dim );§\indexc{bsearchl}§
     6802        E * bsearch( E key, const E * vals, size_t dim );$\indexc{bsearch}$ $\C{// location}$
     6803        size_t bsearch( E key, const E * vals, size_t dim );$\C{// position}$
     6804        E * bsearchl( E key, const E * vals, size_t dim );$\indexc{bsearchl}$
    68166805        size_t bsearchl( E key, const E * vals, size_t dim );
    6817         E * bsearchu( E key, const E * vals, size_t dim );§\indexc{bsearchu}§
     6806        E * bsearchu( E key, const E * vals, size_t dim );$\indexc{bsearchu}$
    68186807        size_t bsearchu( E key, const E * vals, size_t dim );
    68196808}
     
    68296818
    68306819forall( otype E | { int ?<?( E, E ); } ) {
    6831         void qsort( E * vals, size_t dim );§\indexc{qsort}§
     6820        void qsort( E * vals, size_t dim );$\indexc{qsort}$
    68326821}
    68336822\end{cfa}
     
    68386827\leavevmode
    68396828\begin{cfa}[aboveskip=0pt,belowskip=0pt]
    6840 unsigned char abs( signed char );§\indexc{abs}§
     6829unsigned char abs( signed char );$\indexc{abs}$
    68416830int abs( int );
    68426831unsigned long int abs( long int );
     
    68576846\leavevmode
    68586847\begin{cfa}[aboveskip=0pt,belowskip=0pt]
    6859 void srandom( unsigned int seed );§\indexc{srandom}§
    6860 char random( void );§\indexc{random}§
    6861 char random( char u ); §\C{// [0,u)}§
    6862 char random( char l, char u ); §\C{// [l,u)}§
     6848void srandom( unsigned int seed );$\indexc{srandom}$
     6849char random( void );$\indexc{random}$
     6850char random( char u ); $\C{// [0,u)}$
     6851char random( char l, char u ); $\C{// [l,u)}$
    68636852int random( void );
    6864 int random( int u ); §\C{// [0,u)}§
    6865 int random( int l, int u ); §\C{// [l,u)}§
     6853int random( int u ); $\C{// [0,u)}$
     6854int random( int l, int u ); $\C{// [l,u)}$
    68666855unsigned int random( void );
    6867 unsigned int random( unsigned int u ); §\C{// [0,u)}§
    6868 unsigned int random( unsigned int l, unsigned int u ); §\C{// [l,u)}§
     6856unsigned int random( unsigned int u ); $\C{// [0,u)}$
     6857unsigned int random( unsigned int l, unsigned int u ); $\C{// [l,u)}$
    68696858long int random( void );
    6870 long int random( long int u ); §\C{// [0,u)}§
    6871 long int random( long int l, long int u ); §\C{// [l,u)}§
     6859long int random( long int u ); $\C{// [0,u)}$
     6860long int random( long int l, long int u ); $\C{// [l,u)}$
    68726861unsigned long int random( void );
    6873 unsigned long int random( unsigned long int u ); §\C{// [0,u)}§
    6874 unsigned long int random( unsigned long int l, unsigned long int u ); §\C{// [l,u)}§
    6875 float random( void );                                            §\C{// [0.0, 1.0)}§
    6876 double random( void );                                           §\C{// [0.0, 1.0)}§
    6877 float _Complex random( void );                           §\C{// [0.0, 1.0)+[0.0, 1.0)i}§
    6878 double _Complex random( void );                          §\C{// [0.0, 1.0)+[0.0, 1.0)i}§
    6879 long double _Complex random( void );             §\C{// [0.0, 1.0)+[0.0, 1.0)i}§
     6862unsigned long int random( unsigned long int u ); $\C{// [0,u)}$
     6863unsigned long int random( unsigned long int l, unsigned long int u ); $\C{// [l,u)}$
     6864float random( void );                                            $\C{// [0.0, 1.0)}$
     6865double random( void );                                           $\C{// [0.0, 1.0)}$
     6866float _Complex random( void );                           $\C{// [0.0, 1.0)+[0.0, 1.0)i}$
     6867double _Complex random( void );                          $\C{// [0.0, 1.0)+[0.0, 1.0)i}$
     6868long double _Complex random( void );             $\C{// [0.0, 1.0)+[0.0, 1.0)i}$
    68806869\end{cfa}
    68816870
     
    68856874\leavevmode
    68866875\begin{cfa}[aboveskip=0pt,belowskip=0pt]
    6887 forall( otype T | { int ?<?( T, T ); } ) T min( T t1, T t2 );§\indexc{min}§
    6888 forall( otype T | { int ?>?( T, T ); } ) T max( T t1, T t2 );§\indexc{max}§
    6889 forall( otype T | { T min( T, T ); T max( T, T ); } ) T clamp( T value, T min_val, T max_val );§\indexc{clamp}§
    6890 forall( otype T ) void swap( T * t1, T * t2 );§\indexc{swap}§
     6876forall( otype T | { int ?<?( T, T ); } ) T min( T t1, T t2 );$\indexc{min}$
     6877forall( otype T | { int ?>?( T, T ); } ) T max( T t1, T t2 );$\indexc{max}$
     6878forall( otype T | { T min( T, T ); T max( T, T ); } ) T clamp( T value, T min_val, T max_val );$\indexc{clamp}$
     6879forall( otype T ) void swap( T * t1, T * t2 );$\indexc{swap}$
    68916880\end{cfa}
    68926881
     
    69026891\leavevmode
    69036892\begin{cfa}[aboveskip=0pt,belowskip=0pt]
    6904 float ?%?( float, float );§\indexc{fmod}§
     6893float ?%?( float, float );$\indexc{fmod}$
    69056894float fmod( float, float );
    69066895double ?%?( double, double );
     
    69096898long double fmod( long double, long double );
    69106899
    6911 float remainder( float, float );§\indexc{remainder}§
     6900float remainder( float, float );$\indexc{remainder}$
    69126901double remainder( double, double );
    69136902long double remainder( long double, long double );
    69146903
    6915 float remquo( float, float, int * );§\indexc{remquo}§
     6904float remquo( float, float, int * );$\indexc{remquo}$
    69166905double remquo( double, double, int * );
    69176906long double remquo( long double, long double, int * );
     
    69206909[ int, long double ] remquo( long double, long double );
    69216910
    6922 float div( float, float, int * );§\indexc{div}§ §\C{// alternative name for remquo}§
     6911float div( float, float, int * );$\indexc{div}$ $\C{// alternative name for remquo}$
    69236912double div( double, double, int * );
    69246913long double div( long double, long double, int * );
     
    69276916[ int, long double ] div( long double, long double );
    69286917
    6929 float fma( float, float, float );§\indexc{fma}§
     6918float fma( float, float, float );$\indexc{fma}$
    69306919double fma( double, double, double );
    69316920long double fma( long double, long double, long double );
    69326921
    6933 float fdim( float, float );§\indexc{fdim}§
     6922float fdim( float, float );$\indexc{fdim}$
    69346923double fdim( double, double );
    69356924long double fdim( long double, long double );
    69366925
    6937 float nan( const char * );§\indexc{nan}§
     6926float nan( const char * );$\indexc{nan}$
    69386927double nan( const char * );
    69396928long double nan( const char * );
     
    69456934\leavevmode
    69466935\begin{cfa}[aboveskip=0pt,belowskip=0pt]
    6947 float exp( float );§\indexc{exp}§
     6936float exp( float );$\indexc{exp}$
    69486937double exp( double );
    69496938long double exp( long double );
     
    69526941long double _Complex exp( long double _Complex );
    69536942
    6954 float exp2( float );§\indexc{exp2}§
     6943float exp2( float );$\indexc{exp2}$
    69556944double exp2( double );
    69566945long double exp2( long double );
     
    69596948// long double _Complex exp2( long double _Complex );
    69606949
    6961 float expm1( float );§\indexc{expm1}§
     6950float expm1( float );$\indexc{expm1}$
    69626951double expm1( double );
    69636952long double expm1( long double );
    69646953
    6965 float pow( float, float );§\indexc{pow}§
     6954float pow( float, float );$\indexc{pow}$
    69666955double pow( double, double );
    69676956long double pow( long double, long double );
     
    69766965\leavevmode
    69776966\begin{cfa}[aboveskip=0pt,belowskip=0pt]
    6978 float log( float );§\indexc{log}§
     6967float log( float );$\indexc{log}$
    69796968double log( double );
    69806969long double log( long double );
     
    69836972long double _Complex log( long double _Complex );
    69846973
    6985 float log2( float );§\indexc{log2}§
     6974float log2( float );$\indexc{log2}$
    69866975double log2( double );
    69876976long double log2( long double );
     
    69906979// long double _Complex log2( long double _Complex );
    69916980
    6992 float log10( float );§\indexc{log10}§
     6981float log10( float );$\indexc{log10}$
    69936982double log10( double );
    69946983long double log10( long double );
     
    69976986// long double _Complex log10( long double _Complex );
    69986987
    6999 float log1p( float );§\indexc{log1p}§
     6988float log1p( float );$\indexc{log1p}$
    70006989double log1p( double );
    70016990long double log1p( long double );
    70026991
    7003 int ilogb( float );§\indexc{ilogb}§
     6992int ilogb( float );$\indexc{ilogb}$
    70046993int ilogb( double );
    70056994int ilogb( long double );
    70066995
    7007 float logb( float );§\indexc{logb}§
     6996float logb( float );$\indexc{logb}$
    70086997double logb( double );
    70096998long double logb( long double );
    70106999
    7011 float sqrt( float );§\indexc{sqrt}§
     7000float sqrt( float );$\indexc{sqrt}$
    70127001double sqrt( double );
    70137002long double sqrt( long double );
     
    70167005long double _Complex sqrt( long double _Complex );
    70177006
    7018 float cbrt( float );§\indexc{cbrt}§
     7007float cbrt( float );$\indexc{cbrt}$
    70197008double cbrt( double );
    70207009long double cbrt( long double );
    70217010
    7022 float hypot( float, float );§\indexc{hypot}§
     7011float hypot( float, float );$\indexc{hypot}$
    70237012double hypot( double, double );
    70247013long double hypot( long double, long double );
     
    70307019\leavevmode
    70317020\begin{cfa}[aboveskip=0pt,belowskip=0pt]
    7032 float sin( float );§\indexc{sin}§
     7021float sin( float );$\indexc{sin}$
    70337022double sin( double );
    70347023long double sin( long double );
     
    70377026long double _Complex sin( long double _Complex );
    70387027
    7039 float cos( float );§\indexc{cos}§
     7028float cos( float );$\indexc{cos}$
    70407029double cos( double );
    70417030long double cos( long double );
     
    70447033long double _Complex cos( long double _Complex );
    70457034
    7046 float tan( float );§\indexc{tan}§
     7035float tan( float );$\indexc{tan}$
    70477036double tan( double );
    70487037long double tan( long double );
     
    70517040long double _Complex tan( long double _Complex );
    70527041
    7053 float asin( float );§\indexc{asin}§
     7042float asin( float );$\indexc{asin}$
    70547043double asin( double );
    70557044long double asin( long double );
     
    70587047long double _Complex asin( long double _Complex );
    70597048
    7060 float acos( float );§\indexc{acos}§
     7049float acos( float );$\indexc{acos}$
    70617050double acos( double );
    70627051long double acos( long double );
     
    70657054long double _Complex acos( long double _Complex );
    70667055
    7067 float atan( float );§\indexc{atan}§
     7056float atan( float );$\indexc{atan}$
    70687057double atan( double );
    70697058long double atan( long double );
     
    70727061long double _Complex atan( long double _Complex );
    70737062
    7074 float atan2( float, float );§\indexc{atan2}§
     7063float atan2( float, float );$\indexc{atan2}$
    70757064double atan2( double, double );
    70767065long double atan2( long double, long double );
    70777066
    7078 float atan( float, float ); §\C{// alternative name for atan2}§
    7079 double atan( double, double );§\indexc{atan}§
     7067float atan( float, float ); $\C{// alternative name for atan2}$
     7068double atan( double, double );$\indexc{atan}$
    70807069long double atan( long double, long double );
    70817070\end{cfa}
     
    70867075\leavevmode
    70877076\begin{cfa}[aboveskip=0pt,belowskip=0pt]
    7088 float sinh( float );§\indexc{sinh}§
     7077float sinh( float );$\indexc{sinh}$
    70897078double sinh( double );
    70907079long double sinh( long double );
     
    70937082long double _Complex sinh( long double _Complex );
    70947083
    7095 float cosh( float );§\indexc{cosh}§
     7084float cosh( float );$\indexc{cosh}$
    70967085double cosh( double );
    70977086long double cosh( long double );
     
    71007089long double _Complex cosh( long double _Complex );
    71017090
    7102 float tanh( float );§\indexc{tanh}§
     7091float tanh( float );$\indexc{tanh}$
    71037092double tanh( double );
    71047093long double tanh( long double );
     
    71077096long double _Complex tanh( long double _Complex );
    71087097
    7109 float asinh( float );§\indexc{asinh}§
     7098float asinh( float );$\indexc{asinh}$
    71107099double asinh( double );
    71117100long double asinh( long double );
     
    71147103long double _Complex asinh( long double _Complex );
    71157104
    7116 float acosh( float );§\indexc{acosh}§
     7105float acosh( float );$\indexc{acosh}$
    71177106double acosh( double );
    71187107long double acosh( long double );
     
    71217110long double _Complex acosh( long double _Complex );
    71227111
    7123 float atanh( float );§\indexc{atanh}§
     7112float atanh( float );$\indexc{atanh}$
    71247113double atanh( double );
    71257114long double atanh( long double );
     
    71347123\leavevmode
    71357124\begin{cfa}[aboveskip=0pt,belowskip=0pt]
    7136 float erf( float );§\indexc{erf}§
     7125float erf( float );$\indexc{erf}$
    71377126double erf( double );
    71387127long double erf( long double );
     
    71417130long double _Complex erf( long double _Complex );
    71427131
    7143 float erfc( float );§\indexc{erfc}§
     7132float erfc( float );$\indexc{erfc}$
    71447133double erfc( double );
    71457134long double erfc( long double );
     
    71487137long double _Complex erfc( long double _Complex );
    71497138
    7150 float lgamma( float );§\indexc{lgamma}§
     7139float lgamma( float );$\indexc{lgamma}$
    71517140double lgamma( double );
    71527141long double lgamma( long double );
     
    71557144long double lgamma( long double, int * );
    71567145
    7157 float tgamma( float );§\indexc{tgamma}§
     7146float tgamma( float );$\indexc{tgamma}$
    71587147double tgamma( double );
    71597148long double tgamma( long double );
     
    71657154\leavevmode
    71667155\begin{cfa}[aboveskip=0pt,belowskip=0pt]
    7167 float floor( float );§\indexc{floor}§
     7156float floor( float );$\indexc{floor}$
    71687157double floor( double );
    71697158long double floor( long double );
    71707159
    7171 float ceil( float );§\indexc{ceil}§
     7160float ceil( float );$\indexc{ceil}$
    71727161double ceil( double );
    71737162long double ceil( long double );
    71747163
    7175 float trunc( float );§\indexc{trunc}§
     7164float trunc( float );$\indexc{trunc}$
    71767165double trunc( double );
    71777166long double trunc( long double );
    71787167
    7179 float rint( float );§\indexc{rint}§
     7168float rint( float );$\indexc{rint}$
    71807169long double rint( long double );
    71817170long int rint( float );
     
    71867175long long int rint( long double );
    71877176
    7188 long int lrint( float );§\indexc{lrint}§
     7177long int lrint( float );$\indexc{lrint}$
    71897178long int lrint( double );
    71907179long int lrint( long double );
     
    71937182long long int llrint( long double );
    71947183
    7195 float nearbyint( float );§\indexc{nearbyint}§
     7184float nearbyint( float );$\indexc{nearbyint}$
    71967185double nearbyint( double );
    71977186long double nearbyint( long double );
    71987187
    7199 float round( float );§\indexc{round}§
     7188float round( float );$\indexc{round}$
    72007189long double round( long double );
    72017190long int round( float );
     
    72067195long long int round( long double );
    72077196
    7208 long int lround( float );§\indexc{lround}§
     7197long int lround( float );$\indexc{lround}$
    72097198long int lround( double );
    72107199long int lround( long double );
     
    72197208\leavevmode
    72207209\begin{cfa}[aboveskip=0pt,belowskip=0pt]
    7221 float copysign( float, float );§\indexc{copysign}§
     7210float copysign( float, float );$\indexc{copysign}$
    72227211double copysign( double, double );
    72237212long double copysign( long double, long double );
    72247213
    7225 float frexp( float, int * );§\indexc{frexp}§
     7214float frexp( float, int * );$\indexc{frexp}$
    72267215double frexp( double, int * );
    72277216long double frexp( long double, int * );
    72287217
    7229 float ldexp( float, int );§\indexc{ldexp}§
     7218float ldexp( float, int );$\indexc{ldexp}$
    72307219double ldexp( double, int );
    72317220long double ldexp( long double, int );
    72327221
    7233 [ float, float ] modf( float );§\indexc{modf}§
     7222[ float, float ] modf( float );$\indexc{modf}$
    72347223float modf( float, float * );
    72357224[ double, double ] modf( double );
     
    72387227long double modf( long double, long double * );
    72397228
    7240 float nextafter( float, float );§\indexc{nextafter}§
     7229float nextafter( float, float );$\indexc{nextafter}$
    72417230double nextafter( double, double );
    72427231long double nextafter( long double, long double );
    72437232
    7244 float nexttoward( float, long double );§\indexc{nexttoward}§
     7233float nexttoward( float, long double );$\indexc{nexttoward}$
    72457234double nexttoward( double, long double );
    72467235long double nexttoward( long double, long double );
    72477236
    7248 float scalbn( float, int );§\indexc{scalbn}§
     7237float scalbn( float, int );$\indexc{scalbn}$
    72497238double scalbn( double, int );
    72507239long double scalbn( long double, int );
    72517240
    7252 float scalbln( float, long int );§\indexc{scalbln}§
     7241float scalbln( float, long int );$\indexc{scalbln}$
    72537242double scalbln( double, long int );
    72547243long double scalbln( long double, long int );
     
    72677256\begin{cfa}[aboveskip=0pt,belowskip=0pt]
    72687257struct Duration {
    7269         int64_t tv; §\C{// nanoseconds}§
     7258        int64_t tv; $\C{// nanoseconds}$
    72707259};
    72717260
     
    73977386\begin{cfa}[aboveskip=0pt,belowskip=0pt]
    73987387struct Time {
    7399         uint64_t tv; §\C{// nanoseconds since UNIX epoch}§
     7388        uint64_t tv; $\C{// nanoseconds since UNIX epoch}$
    74007389};
    74017390
     
    74687457\begin{cfa}[aboveskip=0pt,belowskip=0pt]
    74697458struct Clock {
    7470         Duration offset; §\C{// for virtual clock: contains offset from real-time}§
    7471         int clocktype; §\C{// implementation only -1 (virtual), CLOCK\_REALTIME}§
     7459        Duration offset; $\C{// for virtual clock: contains offset from real-time}$
     7460        int clocktype; $\C{// implementation only -1 (virtual), CLOCK\_REALTIME}$
    74727461};
    74737462
     
    74777466void ?{}( Clock & clk, Duration adj );
    74787467
    7479 Duration getResNsec(); §\C{// with nanoseconds}§
    7480 Duration getRes(); §\C{// without nanoseconds}§
    7481 
    7482 Time getTimeNsec(); §\C{// with nanoseconds}§
    7483 Time getTime(); §\C{// without nanoseconds}§
     7468Duration getResNsec(); $\C{// with nanoseconds}$
     7469Duration getRes(); $\C{// without nanoseconds}$
     7470
     7471Time getTimeNsec(); $\C{// with nanoseconds}$
     7472Time getTime(); $\C{// without nanoseconds}$
    74847473Time getTime( Clock & clk );
    74857474Time ?()( Clock & clk );
     
    74977486
    74987487\begin{cfa}
    7499 void ?{}( Int * this ); §\C{// constructor/destructor}§
     7488void ?{}( Int * this ); $\C{// constructor/destructor}$
    75007489void ?{}( Int * this, Int init );
    75017490void ?{}( Int * this, zero_t );
     
    75067495void ^?{}( Int * this );
    75077496
    7508 Int ?=?( Int * lhs, Int rhs ); §\C{// assignment}§
     7497Int ?=?( Int * lhs, Int rhs ); $\C{// assignment}$
    75097498Int ?=?( Int * lhs, long int rhs );
    75107499Int ?=?( Int * lhs, unsigned long int rhs );
     
    75237512unsigned long int narrow( Int val );
    75247513
    7525 int ?==?( Int oper1, Int oper2 ); §\C{// comparison}§
     7514int ?==?( Int oper1, Int oper2 ); $\C{// comparison}$
    75267515int ?==?( Int oper1, long int oper2 );
    75277516int ?==?( long int oper2, Int oper1 );
     
    75597548int ?>=?( unsigned long int oper1, Int oper2 );
    75607549
    7561 Int +?( Int oper ); §\C{// arithmetic}§
     7550Int +?( Int oper ); $\C{// arithmetic}$
    75627551Int -?( Int oper );
    75637552Int ~?( Int oper );
     
    76417630Int ?>>=?( Int * lhs, mp_bitcnt_t shift );
    76427631
    7643 Int abs( Int oper ); §\C{// number functions}§
     7632Int abs( Int oper ); $\C{// number functions}$
    76447633Int fact( unsigned long int N );
    76457634Int gcd( Int oper1, Int oper2 );
     
    76537642Int sqrt( Int oper );
    76547643
    7655 forall( dtype istype | istream( istype ) ) istype * ?|?( istype * is, Int * mp );  §\C{// I/O}§
     7644forall( dtype istype | istream( istype ) ) istype * ?|?( istype * is, Int * mp );  $\C{// I/O}$
    76567645forall( dtype ostype | ostream( ostype ) ) ostype * ?|?( ostype * os, Int mp );
    76577646\end{cfa}
     
    76647653\hline
    76657654\begin{cfa}
    7666 #include <gmp>§\indexc{gmp}§
     7655#include <gmp>$\indexc{gmp}$
    76677656int main( void ) {
    76687657        sout | "Factorial Numbers";
     
    76787667&
    76797668\begin{cfa}
    7680 #include <gmp.h>§\indexc{gmp.h}§
     7669#include <gmp.h>$\indexc{gmp.h}$
    76817670int main( void ) {
    7682         ®gmp_printf®( "Factorial Numbers\n" );
    7683         ®mpz_t® fact;
    7684         ®mpz_init_set_ui®( fact, 1 );
    7685         ®gmp_printf®( "%d %Zd\n", 0, fact );
     7671        @gmp_printf@( "Factorial Numbers\n" );
     7672        @mpz_t@ fact;
     7673        @mpz_init_set_ui@( fact, 1 );
     7674        @gmp_printf@( "%d %Zd\n", 0, fact );
    76867675        for ( unsigned int i = 1; i <= 40; i += 1 ) {
    7687                 ®mpz_mul_ui®( fact, fact, i );
    7688                 ®gmp_printf®( "%d %Zd\n", i, fact );
     7676                @mpz_mul_ui@( fact, fact, i );
     7677                @gmp_printf@( "%d %Zd\n", i, fact );
    76897678        }
    76907679}
     
    77517740\begin{cfa}[belowskip=0pt]
    77527741// implementation
    7753 struct Rational {§\indexc{Rational}§
    7754         long int numerator, denominator; §\C{// invariant: denominator > 0}§
     7742struct Rational {$\indexc{Rational}$
     7743        long int numerator, denominator; $\C{// invariant: denominator > 0}$
    77557744}; // Rational
    77567745
    7757 Rational rational(); §\C{// constructors}§
     7746Rational rational(); $\C{// constructors}$
    77587747Rational rational( long int n );
    77597748Rational rational( long int n, long int d );
     
    77617750void ?{}( Rational * r, one_t );
    77627751
    7763 long int numerator( Rational r ); §\C{// numerator/denominator getter/setter}§
     7752long int numerator( Rational r ); $\C{// numerator/denominator getter/setter}$
    77647753long int numerator( Rational r, long int n );
    77657754long int denominator( Rational r );
    77667755long int denominator( Rational r, long int d );
    77677756
    7768 int ?==?( Rational l, Rational r ); §\C{// comparison}§
     7757int ?==?( Rational l, Rational r ); $\C{// comparison}$
    77697758int ?!=?( Rational l, Rational r );
    77707759int ?<?( Rational l, Rational r );
     
    77737762int ?>=?( Rational l, Rational r );
    77747763
    7775 Rational -?( Rational r ); §\C{// arithmetic}§
     7764Rational -?( Rational r ); $\C{// arithmetic}$
    77767765Rational ?+?( Rational l, Rational r );
    77777766Rational ?-?( Rational l, Rational r );
     
    77797768Rational ?/?( Rational l, Rational r );
    77807769
    7781 double widen( Rational r ); §\C{// conversion}§
     7770double widen( Rational r ); $\C{// conversion}$
    77827771Rational narrow( double f, long int md );
    77837772
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