Index: doc/papers/general/Paper.tex =================================================================== --- doc/papers/general/Paper.tex (revision c4d4ecf2236c625c2cb2120b42a876a14cc53dff) +++ doc/papers/general/Paper.tex (revision 8f67d442595ccba6342b86d7428843dd8b34c353) @@ -4,19 +4,20 @@ \usepackage{epic,eepic} \usepackage{xspace,calc,comment} -\usepackage{upquote} % switch curled `'" to straight -\usepackage{listings} % format program code +\usepackage{upquote} % switch curled `'" to straight +\usepackage{listings} % format program code +\usepackage[flushmargin]{footmisc} % support label/reference in footnote \usepackage{rotating} \usepackage[usenames]{color} -\usepackage{pslatex} % reduce size of san serif font +\usepackage{pslatex} % reduce size of san serif font \usepackage[plainpages=false,pdfpagelabels,pdfpagemode=UseNone,pagebackref=true,breaklinks=true,colorlinks=true,linkcolor=blue,citecolor=blue,urlcolor=blue]{hyperref} \setlength{\textheight}{9in} %\oddsidemargin 0.0in -\renewcommand{\topfraction}{0.8} % float must be greater than X of the page before it is forced onto its own page -\renewcommand{\bottomfraction}{0.8} % float must be greater than X of the page before it is forced onto its own page -\renewcommand{\floatpagefraction}{0.8} % float must be greater than X of the page before it is forced onto its own page -\renewcommand{\textfraction}{0.0} % the entire page maybe devoted to floats with no text on the page at all - -\lefthyphenmin=4 % hyphen only after 4 characters +\renewcommand{\topfraction}{0.8} % float must be greater than X of the page before it is forced onto its own page +\renewcommand{\bottomfraction}{0.8} % float must be greater than X of the page before it is forced onto its own page +\renewcommand{\floatpagefraction}{0.8} % float must be greater than X of the page before it is forced onto its own page +\renewcommand{\textfraction}{0.0} % the entire page maybe devoted to floats with no text on the page at all + +\lefthyphenmin=4 % hyphen only after 4 characters \righthyphenmin=4 @@ -24,7 +25,7 @@ \newcommand{\CFAIcon}{\textsf{C}\raisebox{\depth}{\rotatebox{180}{\textsf{A}}}\xspace} % Cforall symbolic name -\newcommand{\CFA}{\protect\CFAIcon} % safe for section/caption -\newcommand{\CFL}{\textrm{Cforall}\xspace} % Cforall symbolic name -\newcommand{\Celeven}{\textrm{C11}\xspace} % C11 symbolic name +\newcommand{\CFA}{\protect\CFAIcon} % safe for section/caption +\newcommand{\CFL}{\textrm{Cforall}\xspace} % Cforall symbolic name +\newcommand{\Celeven}{\textrm{C11}\xspace} % C11 symbolic name \newcommand{\CC}{\textrm{C}\kern-.1em\hbox{+\kern-.25em+}\xspace} % C++ symbolic name \newcommand{\CCeleven}{\textrm{C}\kern-.1em\hbox{+\kern-.25em+}11\xspace} % C++11 symbolic name @@ -56,5 +57,5 @@ \newcommand{\LstCommentStyle}[1]{{\lst@basicstyle{\lst@commentstyle{#1}}}} -\newlength{\gcolumnposn} % temporary hack because lstlisting does not handle tabs correctly +\newlength{\gcolumnposn} % temporary hack because lstlisting does not handle tabs correctly \newlength{\columnposn} \setlength{\gcolumnposn}{2.75in} @@ -72,5 +73,5 @@ % Latin abbreviation -\newcommand{\abbrevFont}{\textit} % set empty for no italics +\newcommand{\abbrevFont}{\textit} % set empty for no italics \newcommand{\EG}{\abbrevFont{e}.\abbrevFont{g}.} \newcommand*{\eg}{% @@ -1116,5 +1117,5 @@ \CFA disallows the declaration of local variable, \eg @z@, directly within the @switch@ body, because a declaration cannot occur immediately after a @case@ since a label can only be attached to a statement, and the use of @z@ is undefined in @case 1@ as neither storage allocation nor initialization may have occurred. -C @switch@ provides multiple entry points into the statement body, but once an entry point is selected, control continues across \emph{all} @case@ clauses until the end of the @switch@ body, called \newterm{fall through}. +C @switch@ provides multiple entry points into the statement body, but once an entry point is selected, control continues across \emph{all} @case@ clauses until the end of the @switch@ body, called \newterm{fall through}; @case@ clauses are made disjoint by the @break@ statement. While the ability to fall through \emph{is} a useful form of control flow, it does not match well with programmer intuition, resulting in many errors from missing @break@ statements. @@ -1538,4 +1539,49 @@ Therefore, a programmer has the option of either continuing to use traditional C declarations or take advantage of the new style. Clearly, both styles need to be supported for some time due to existing C-style header-files, particularly for UNIX-like systems. + +The syntax of the new routine prototype declaration follows directly from the new routine definition syntax; +as well, parameter names are optional, \eg: +\begin{cfa} +[ int x ] f (); $\C{// returning int with no parameters}$ +[ * int ] g (int y); $\C{// returning pointer to int with int parameter}$ +[ ] h ( int, char ); $\C{// returning no result with int and char parameters}$ +[ * int, int ] j ( int ); $\C{// returning pointer to int and int, with int parameter}$ +\end{cfa} +This syntax allows a prototype declaration to be created by cutting and pasting source text from the routine definition header (or vice versa). +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, \eg: +\begin{cquote} +\lstDeleteShortInline@% +\begin{tabular}{@{}l@{\hspace{3em}}l@{}} +\multicolumn{1}{c@{\hspace{3em}}}{\textbf{\CFA}} & \multicolumn{1}{c}{\textbf{C}} \\ +\begin{cfa} +[double] foo(), foo( int ), foo( double ) {...} +\end{cfa} +& +\begin{cfa} +double foo1(), foo2( int ), foo3( double ); +\end{cfa} +\end{tabular} +\lstMakeShortInline@% +\end{cquote} +\CFA allows the last routine in the list to define its body. + +Declaration qualifiers can only appear at the start of a \CFA routine declaration,\footref{StorageClassSpecifier} \eg: +\begin{cfa} +extern [ int ] f ( int ); +static [ int ] g ( int ); +\end{cfa} + +The syntax for pointers to \CFA routines specifies the pointer name on the right, \eg: +\begin{cfa} +* [ int x ] () fp; $\C{// pointer to routine returning int with no parameters}$ +* [ * int ] (int y) gp; $\C{// pointer to routine returning pointer to int with int parameter}$ +* [ ] (int,char) hp; $\C{// pointer to routine returning no result with int and char parameters}$ +* [ * int,int ] ( int ) jp; $\C{// pointer to routine returning pointer to int and int, with int parameter}$ +\end{cfa} +While parameter names are optional, \emph{a routine name cannot be specified}; +for example, the following is incorrect: +\begin{cfa} +* [ int x ] f () fp; $\C{// routine name "f" is not allowed}$ +\end{cfa} @@ -1764,4 +1810,97 @@ \end{cfa} }% + + +\section{Libraries} + +\subsection{I/O} +\label{s:IOLibrary} + +The goal of \CFA I/O is to simplify the common cases, while fully supporting polymorphism and user defined types in a consistent way. +The approach combines ideas from \CC and Python. +The \CFA header file for the I/O library is @fstream@. + +The common case is printing out a sequence of variables separated by whitespace. +\begin{cquote} +\lstDeleteShortInline@% +\begin{tabular}{@{}l@{\hspace{3em}}l@{}} +\multicolumn{1}{c@{\hspace{3em}}}{\textbf{\CFA}} & \multicolumn{1}{c}{\textbf{\CC}} \\ +\begin{cfa} +int x = 1, y = 2, z = 3; +sout | x `|` y `|` z | endl; +\end{cfa} +& +\begin{cfa} + +cout << x `<< " "` << y `<< " "` << z << endl; +\end{cfa} +\\ +\begin{cfa}[showspaces=true,aboveskip=0pt,belowskip=0pt] +1` `2` `3 +\end{cfa} +& +\begin{cfa}[showspaces=true,aboveskip=0pt,belowskip=0pt] +1 2 3 +\end{cfa} +\end{tabular} +\lstMakeShortInline@% +\end{cquote} +The \CFA form has half the characters of the \CC form, and is similar to Python I/O with respect to implicit separators. +Similar simplification occurs for tuple I/O, which prints all tuple values separated by ``\lstinline[showspaces=true]@, @''. +\begin{cfa} +[int, [ int, int ] ] t1 = [ 1, [ 2, 3 ] ], t2 = [ 4, [ 5, 6 ] ]; +sout | t1 | t2 | endl; $\C{// print tuples}$ +\end{cfa} +\begin{cfa}[showspaces=true,aboveskip=0pt] +1`, `2`, `3 4`, `5`, `6 +\end{cfa} +Finally, \CFA uses the logical-or operator for I/O as it is the lowest-priority overloadable operator, other than assignment. +Therefore, fewer output expressions require parenthesis. +\begin{cquote} +\lstDeleteShortInline@% +\begin{tabular}{@{}ll@{}} +\textbf{\CFA:} +& +\begin{cfa} +sout | x * 3 | y + 1 | z << 2 | x == y | (x | y) | (x || y) | (x > z ? 1 : 2) | endl; +\end{cfa} +\\ +\textbf{\CC:} +& +\begin{cfa} +cout << x * 3 << y + 1 << `(`z << 2`)` << `(`x == y`)` << (x | y) << (x || y) << (x > z ? 1 : 2) << endl; +\end{cfa} +\\ +\textbf{output:} +& +\begin{cfa}[showspaces=true,aboveskip=0pt] +3 3 12 0 3 1 2 +\end{cfa} +\end{tabular} +\lstMakeShortInline@% +\end{cquote} +There is a weak similarity between the \CFA logical-or operator and the Shell pipe-operator for moving data, where data flows in the correct direction for input but the opposite direction for output. + +The implicit separator character (space/blank) is a separator not a terminator. +The rules for implicitly adding the separator are: +\begin{list}{\footnotesize$\bullet$}{\itemsep=2pt\parsep=0pt} +\item +A separator does not appear at the start or end of a line. +\item +A separator does not appear before or after a character literal or variable. +\item +A separator does not appear before or after a null (empty) C string, which is a local mechanism to disable insertion of the separator character. +\item +A separator does not appear before a C string starting with the characters: \lstinline[mathescape=off,basicstyle=\tt]@([{=$@ +\item +A seperator does not appear after a C string ending with the characters: \lstinline[basicstyle=\tt]@,.;!?)]}%@ +\item +{\lstset{language=CFA,deletedelim=**[is][]{`}{`}} +A seperator does not appear before or after a C string begining/ending with the quote or whitespace characters: \lstinline[basicstyle=\tt,showspaces=true]@`'": \t\v\f\r\n@ +}% +\item +There are routines to set and get the separator string, and manipulators to toggle separation on and off in the middle of output. +\end{list} + \section{Evaluation}