Changeset 43bbdf3

Timestamp:

Feb 5, 2018, 9:09:44 PM (6 years ago)

Author:

Peter A. Buhr <pabuhr@…>

Branches:

ADT, aaron-thesis, arm-eh, ast-experimental, cleanup-dtors, deferred_resn, demangler, enum, forall-pointer-decay, jacob/cs343-translation, jenkins-sandbox, master, new-ast, new-ast-unique-expr, new-env, no_list, persistent-indexer, pthread-emulation, qualifiedEnum, resolv-new, with_gc

Children:

6bfe5cc

Parents:

cbe477e

Message:

initial work in "with" clause/statement

File:

• doc/papers/general/Paper.tex (modified) (6 diffs)

doc/papers/general/Paper.tex

@@ -61 +61 @@
 \newcommand{\C}[2][\@empty]{\ifx#1\@empty\else\global\setlength{\columnposn}{#1}\global\columnposn=\columnposn\fi\hfill\makebox[\textwidth-\columnposn][l]{\lst@basicstyle{\LstCommentStyle{#2}}}}
 \newcommand{\CRT}{\global\columnposn=\gcolumnposn}
+
+% Denote newterms in particular font and index them without particular font and in lowercase, e.g., \newterm{abc}.
+% The option parameter provides an index term different from the new term, e.g., \newterm[\texttt{abc}]{abc}
+% The star version does not lowercase the index information, e.g., \newterm*{IBM}.
+\newcommand{\newtermFontInline}{\emph}
+\newcommand{\newterm}{\@ifstar\@snewterm\@newterm}
+\newcommand{\@newterm}[2][\@empty]{\lowercase{\def\temp{#2}}{\newtermFontInline{#2}}\ifx#1\@empty\index{\temp}\else\index{#1@{\protect#2}}\fi}
+\newcommand{\@snewterm}[2][\@empty]{{\newtermFontInline{#2}}\ifx#1\@empty\index{#2}\else\index{#1@{\protect#2}}\fi}
 
 % Latin abbreviation
@@ -1040 +1048 @@
 \TODO{choose and fallthrough here as well?}
 
+
 \subsection{\texorpdfstring{\LstKeywordStyle{with} Clause / Statement}{with Clause / Statement}}
 \label{s:WithClauseStatement}
 
-In any programming language, some functions have a naturally close relationship with a particular data type. 
-Object-oriented programming allows this close relationship to be codified in the language by making such functions \emph{class methods} of their related data type.
-Class methods have certain privileges with respect to their associated data type, notably un-prefixed access to the fields of that data type. 
-When writing C functions in an object-oriented style, this un-prefixed access is swiftly missed, as access to fields of a @Foo* f@ requires an extra three characters @f->@ every time, which disrupts coding flow and clutters the produced code. 
-
-\TODO{Fill out section. Be sure to mention arbitrary expressions in with-blocks, recent change driven by Thierry to prioritize field name over parameters.}
-
-
-In object-oriented programming, there is an implicit first parameter, often names @self@ or @this@, which is elided.
+Grouping heterogenous data into \newterm{aggregate}s is a common programming practice, and an aggregate can be further organized into more complex structures, such as arrays and containers:
+\begin{cfa}
+struct S {                                                              $\C{// aggregate}$
+        char c;                                                         $\C{// fields}$
+        int i;
+        double d;
+};
+S s, as[10];
+\end{cfa}
+However, routines manipulating aggregates have repeition of the aggregate name to access its containing fields:
+\begin{cfa}
+void f( S s ) {
+        `s.`c; `s.`i; `s.`d;                            $\C{// access containing fields}$
+}
+\end{cfa}
+A similar situation occurs in object-oriented programming, \eg \CC:
 \begin{C++}
 class C {
-        int i, j;
-        int mem() {                                     $\C{\color{red}// implicit "this" parameter}$
-                i = 1;                                  $\C{\color{red}// this-{\textgreater}i}$
-                j = 2;                                  $\C{\color{red}// this-{\textgreater}j}$
+        char c;                                                         $\C{// fields}$
+        int i;
+        double d;
+        int mem() {                                                     $\C{// implicit "this" parameter}$
+                `this->`c; `this->`i; `this->`d;$\C{// access containing fields}$
         }
 }
 \end{C++}
-Since \CFA is non-object-oriented, the equivalent object-oriented program looks like:
+Nesting of member routines in a \lstinline[language=C++]@class@ allows eliding \lstinline[language=C++]@this->@ because of nested lexical-scoping.
+
+% In object-oriented programming, there is an implicit first parameter, often names @self@ or @this@, which is elided.
+% In any programming language, some functions have a naturally close relationship with a particular data type. 
+% Object-oriented programming allows this close relationship to be codified in the language by making such functions \emph{class methods} of their related data type.
+% Class methods have certain privileges with respect to their associated data type, notably un-prefixed access to the fields of that data type. 
+% When writing C functions in an object-oriented style, this un-prefixed access is swiftly missed, as access to fields of a @Foo* f@ requires an extra three characters @f->@ every time, which disrupts coding flow and clutters the produced code. 
+% 
+% \TODO{Fill out section. Be sure to mention arbitrary expressions in with-blocks, recent change driven by Thierry to prioritize field name over parameters.}
+
+\CFA provides a @with@ clause/statement (see Pascal~\cite[\S~4.F]{Pascal}) to elided aggregate qualification to fields by opening a scope containing field identifiers.
+Hence, the qualified fields become variables, and making it easier to optimizing field references in a block.
 \begin{cfa}
-struct S { int i, j; };
-int mem( S & `this` ) {                 $\C{// explicit "this" parameter}$
-        `this.`i = 1;                           $\C{// "this" is not elided}$
-        `this.`j = 2;
+void f( S s ) `with s` {                                $\C{// with clause}$
+        c; i; d;                                                        $\C{\color{red}// s.c, s.i, s.d}$
 }
 \end{cfa}
-but it is cumbersome having to write "this." many times in a member.
-
-\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.
+and the equivalence for object-style programming is:
 \begin{cfa}
-int mem( S &this ) `with this` { $\C{// with clause}$
-        i = 1;                                          $\C{\color{red}// this.i}$
-        j = 2;                                          $\C{\color{red}// this.j}$
+int mem( S & this ) `with this` {               $\C{// with clause}$
+        c; i; d;                                                        $\C{\color{red}// this.c, this.i, this.d}$
 }
 \end{cfa}
-which extends to multiple routine parameters:
+The key generality over the object-oriented approach is that one aggregate parameter \lstinline[language=C++]@this@ is not treated specially over other aggregate parameters:
 \begin{cfa}
 struct T { double m, n; };
-int mem2( S & this1, T & this2 ) `with this1, this2` {
-        i = 1; j = 2;
-        m = 1.0; n = 2.0;
+int mem( S & s, T & t ) `with s, t` {   $\C{// multiple aggregate parameters}$
+        c; i; d;                                                        $\C{\color{red}// s.c, s.i, s.d}$
+        m; n;                                                           $\C{\color{red}// t.m, t.n}$
+}
+\end{cfa}
+The equivalent object-oriented style is:
+\begin{cfa}
+int S::mem( T & t ) {                                   $\C{// multiple aggregate parameters}$
+        c; i; d;                                                        $\C{\color{red}// this-\textgreater.c, this-\textgreater.i, this-\textgreater.d}$
+        `t.`m; `t.`n;
 }
 \end{cfa}
@@ -1092 +1122 @@
         struct S1 { ... } s1;
         struct S2 { ... } s2;
-        `with s1` {                                     $\C{// with statement}$
+        `with s1` {                                             $\C{// with statement}$
                 // access fields of s1 without qualification
-                `with s2` {                             $\C{// nesting}$
+                `with s2` {                                     $\C{// nesting}$
                         // access fields of s1 and s2 without qualification
                 }
@@ -1110 +1140 @@
 struct T { int i; int k; int m } b, c;
 `with a, b` {
-        j + k;                                          $\C{// unambiguous, unique names define unique types}$
-        i;                                                      $\C{// ambiguous, same name and type}$
-        a.i + b.i;                                      $\C{// unambiguous, qualification defines unique names}$
-        m;                                                      $\C{// ambiguous, same name and no context to define unique type}$
-        m = 5.0;                                        $\C{// unambiguous, same name and context defines unique type}$
-        m = 1;                                          $\C{// unambiguous, same name and context defines unique type}$
-}
-`with c` { ... }                                $\C{// ambiguous, same name and no context}$
-`with (S)c` { ... }                             $\C{// unambiguous, same name and cast defines unique type}$
+        j + k;                                                  $\C{// unambiguous, unique names define unique types}$
+        i;                                                              $\C{// ambiguous, same name and type}$
+        a.i + b.i;                                              $\C{// unambiguous, qualification defines unique names}$
+        m;                                                              $\C{// ambiguous, same name and no context to define unique type}$
+        m = 5.0;                                                $\C{// unambiguous, same name and context defines unique type}$
+        m = 1;                                                  $\C{// unambiguous, same name and context defines unique type}$
+}
+`with c` { ... }                                        $\C{// ambiguous, same name and no context}$
+`with (S)c` { ... }                                     $\C{// unambiguous, same name and cast defines unique type}$
 \end{cfa}
 
@@ -1226 +1256 @@
 \TODO{Pull more draft text from user manual; make sure to discuss initialization and reference conversions}
 
+
 \subsection{Constructors and Destructors}
 
@@ -1244 +1275 @@
 
 \TODO{Some text already at the end of Section~\ref{sec:poly-fns}}
+
 
 \subsection{Units}