Changes in doc/user/user.tex [d92ff4a:ba80f99]
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rd92ff4a rba80f99 1 1 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%% -*- Mode: Latex -*- %%%%%%%%%%%%%%%%%%%%%%%%%%%% 2 %% 2 %% 3 3 %% Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo 4 4 %% 5 5 %% The contents of this file are covered under the licence agreement in the 6 6 %% file "LICENCE" distributed with Cforall. 7 %% 8 %% user.tex -- 9 %% 7 %% 8 %% user.tex -- 9 %% 10 10 %% Author : Peter A. Buhr 11 11 %% Created On : Wed Apr 6 14:53:29 2016 12 12 %% Last Modified By : Peter A. Buhr 13 %% Last Modified On : Thu Jul 26 17:29:05201814 %% Update Count : 33 6613 %% Last Modified On : Fri Aug 31 07:54:50 2018 14 %% Update Count : 3396 15 15 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 16 16 … … 72 72 73 73 % Names used in the document. 74 \newcommand{\Version}{\input{ ../../version}}74 \newcommand{\Version}{\input{build/version}} 75 75 \newcommand{\Textbf}[2][red]{{\color{#1}{\textbf{#2}}}} 76 76 \newcommand{\Emph}[2][red]{{\color{#1}\textbf{\emph{#2}}}} … … 210 210 Even with all its problems, C continues to be popular because it allows writing software at virtually any level in a computer system without restriction. 211 211 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. 212 The TIOBE index~\cite{TIOBE} for July 2018 ranks the top 5 most \emph{popular} programming languages as:\Index*{Java} 16\%, C 14\%, \Index*[C++]{\CC{}} 7.5\%, Python 6\%, Visual Basic 4\% = 47.5\%, where the next 50 languages are less than 4\% each, with a long tail.212 The TIOBE index~\cite{TIOBE} for July 2018 ranks the top five most \emph{popular} programming languages as \Index*{Java} 16\%, C 14\%, \Index*[C++]{\CC{}} 7.5\%, Python 6\%, Visual Basic 4\% = 47.5\%, where the next 50 languages are less than 4\% each, with a long tail. 213 213 The top 3 rankings over the past 30 years are: 214 214 \begin{center} … … 351 351 The 2011 C standard plus GNU extensions. 352 352 \item 353 \Indexc[deletekeywords=inline]{-fgnu89-inline}\index{compilation option!-fgnu89-inline@{\lstinline[deletekeywords=inline] @-fgnu89-inline@}}353 \Indexc[deletekeywords=inline]{-fgnu89-inline}\index{compilation option!-fgnu89-inline@{\lstinline[deletekeywords=inline]$-fgnu89-inline$}} 354 354 Use the traditional GNU semantics for inline routines in C11 mode, which allows inline routines in header files. 355 355 \end{description} … … 430 430 #endif 431 431 \end{cfa} 432 which conditionally includes the correct header file, if the program is compiled using \Indexc{gcc} or \Indexc{cfa}. 432 which conditionally includes the correct header file, if the program is compiled using \Indexc{gcc} or \Indexc{cfa}. 433 433 434 434 … … 455 455 #endif 456 456 457 ®#include_next <bfdlink.h> 457 ®#include_next <bfdlink.h> §\C{// must have internal check for multiple expansion}§ 458 458 ® 459 459 #if defined( with ) && defined( __CFA_BFD_H__ ) §\C{// reset only if set}§ … … 504 504 505 505 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}, to perform the exponentiation operation. 506 \CFA extends the basic operators with the exponentiation operator ©?\?©\index{?\\?@ \lstinline@?\?@} and ©?\=?©\index{?\\=?@\lstinline@?\=?@}, as in, ©x \ y© and ©x \= y©, which means $x^y$ and $x \leftarrow x^y$.506 \CFA extends the basic operators with the exponentiation operator ©?\?©\index{?\\?@©?\?©} and ©?\=?©\index{?\\=?@©\=?©}, as in, ©x \ y© and ©x \= y©, which means $x^y$ and $x \leftarrow x^y$. 507 507 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)©. 508 508 … … 516 516 256 64 -64 0.015625 -0.015625 18.3791736799526 0.264715-1.1922i 517 517 \end{cfa} 518 Parenthesis are necessary for the complex constants or the expression is parsed as ©1.0f+(2.0fi \ 3.0f)+2.0fi©.518 Parenthesis are necessary for complex constants or the expression is parsed as ©1.0f+®(®2.0fi \ 3.0f®)®+2.0fi©. 519 519 The exponentiation operator is available for all the basic types, but for user-defined types, only the integral-computation versions are available. 520 520 For returning an integral value, the user type ©T© must define multiplication, ©*©, and one, ©1©; … … 527 527 528 528 529 %\subsection{\texorpdfstring{\protect\lstinline@if@ Statement}{if Statement}} 530 \subsection{\texorpdfstring{\LstKeywordStyle{if} Statement}{if Statement}} 531 532 The ©if© expression allows declarations, similar to ©for© declaration expression: 533 \begin{cfa} 534 if ( int x = f() ) ... §\C{// x != 0}§ 535 if ( int x = f(), y = g() ) ... §\C{// x != 0 \&\& y != 0}§ 536 if ( int x = f(), y = g(); ®x < y® ) ... §\C{// relational expression}§ 537 \end{cfa} 538 Unless a relational expression is specified, each variable is compared not equal to 0, which is the standard semantics for the ©if© expression, and the results are combined using the logical ©&&© operator.\footnote{\CC only provides a single declaration always compared not equal to 0.} 529 %\subsection{\texorpdfstring{\protect\lstinline@if@/\protect\lstinline@while@ Statement}{if Statement}} 530 \subsection{\texorpdfstring{\LstKeywordStyle{if}/\LstKeywordStyle{while} Statement}{if/while Statement}} 531 532 The ©if©/©while© expression allows declarations, similar to ©for© declaration expression. 533 (Does not make sense for ©do©-©while©.) 534 \begin{cfa} 535 if ( ®int x = f()® ) ... §\C{// x != 0}§ 536 if ( ®int x = f(), y = g()® ) ... §\C{// x != 0 \&\& y != 0}§ 537 if ( ®int x = f(), y = g(); x < y® ) ... §\C{// relational expression}§ 538 if ( ®struct S { int i; } x = { f() }; x.i < 4® ) §\C{// relational expression}§ 539 540 while ( ®int x = f()® ) ... §\C{// x != 0}§ 541 while ( ®int x = f(), y = g()® ) ... §\C{// x != 0 \&\& y != 0}§ 542 while ( ®int x = f(), y = g(); x < y® ) ... §\C{// relational expression}§ 543 while ( ®struct S { int i; } x = { f() }; x.i < 4® ) ... §\C{// relational expression}§ 544 \end{cfa} 545 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.} 539 546 The scope of the declaration(s) is local to the @if@ statement but exist within both the ``then'' and ``else'' clauses. 547 548 549 %\subsection{\texorpdfstring{\protect\lstinline@for@ Statement}{for Statement}} 550 \subsection{\texorpdfstring{\LstKeywordStyle{for} Statement}{for Statement}} 551 552 The ©for©/©while©/©do-while© loop-control allows empty or simplified ranges. 553 An empty conditional implies ©1©. 554 The up-to range ©~©\index{~@©~©} means exclusive range [M,N); 555 the up-to range ©~=©\index{~=@©~=©} means inclusive range [M,N]. 556 The down-to range ©-~©\index{-~@©-~©} means exclusive range [N,M); 557 the down-to range ©-~=©\index{-~=@©-~=©} means inclusive range [N,M]. 558 ©0© is the implicit start value; 559 ©1© is the implicit increment value for an up-to range and ©-1© for an implicit down-to range. 560 The loop index is polymorphic in the type of the start value or comparison value when start is implicitly ©0©. 561 \begin{cquote} 562 \begin{tabular}{@{}ll|l@{}} 563 \multicolumn{2}{c|}{for control} & \multicolumn{1}{c}{output} \\ 564 \hline 565 \begin{cfa} 566 while ®()® { sout | "empty"; break; } 567 do { sout | "empty"; break; } while ®()®; 568 for ®()® { sout | "empty"; break; } 569 for ( ®0® ) { sout | "A"; } 570 for ( ®1® ) { sout | "A"; } 571 for ( ®10® ) { sout | "A"; } 572 for ( ®1 ~= 10 ~ 2® ) { sout | "B"; } 573 for ( ®10 -~= 1 ~ -2® ) { sout | "C"; } 574 for ( ®0.5 ~ 5.5® ) { sout | "D"; } 575 for ( ®5.5 -~ 0.5® ) { sout | "E"; } 576 for ( ®i; 10® ) { sout | i; } 577 for ( ®i; 1 ~= 10 ~ 2® ) { sout | i; } 578 for ( ®i; 10 -~= 1 ~ -2® ) { sout | i; } 579 for ( ®i; 0.5 ~ 5.5® ) { sout | i; } 580 for ( ®i; 5.5 -~ 0.5® ) { sout | i; } 581 for ( ®ui; 2u ~= 10u ~ 2u® ) { sout | ui; } 582 for ( ®ui; 10u -~= 2u ~ -2u® ) { sout | ui; } 583 int start = 3, comp = 10, inc = 2; 584 for ( ®i; start ~ comp ~ inc + 1® ) { sout | i; } 585 \end{cfa} 586 & 587 \begin{cfa} 588 sout | endl; 589 sout | endl; 590 sout | endl; 591 sout | endl; 592 sout | endl; 593 sout | endl; 594 sout | endl; 595 sout | endl; 596 sout | endl; 597 sout | endl; 598 sout | endl; 599 sout | endl; 600 sout | endl; 601 sout | endl; 602 sout | endl; 603 sout | endl; 604 sout | endl; 605 606 sout | endl; 607 \end{cfa} 608 & 609 \begin{cfa} 610 empty 611 empty 612 empty 613 614 A 615 A A A A A A A A A A 616 B B B B B 617 C C C C C 618 D D D D D 619 E E E E E 620 0 1 2 3 4 5 6 7 8 9 621 1 3 5 7 9 622 10 8 6 4 2 623 0.5 1.5 2.5 3.5 4.5 624 5.5 4.5 3.5 2.5 1.5 625 2 4 6 8 10 626 10 8 6 4 2 627 628 3 6 9 629 \end{cfa} 630 \end{tabular} 631 \end{cquote} 540 632 541 633 … … 800 892 801 893 894 % for () => for ( ;; ) 895 % for ( 10 - t ) => for ( typeof(10 - t) ? = 0 ; ? < 10 - t; ? += 1 ) // using 0 and 1 896 % for ( i ; 10 - t ) => for ( typeof(10 - t) i = 0 ; i < 10 - t; i += 1 ) // using 0 and 1 897 % for ( T i ; 10 - t ) => for ( T i = 0 ; i < 10 - t; i += 1 ) // using 0 and 1 898 % for ( 3~9 ) => for ( int ? = 3 ; ? < 9; ? += 1 ) // using 1 899 % for ( i ; 3~9 ) => for ( int i = 3 ; i < 9; i += 1 ) // using 1 900 % for ( T i ; 3~9 ) => for ( T i = 3 ; i < 9; i += 1 ) // using 1 901 902 802 903 %\subsection{\texorpdfstring{Labelled \protect\lstinline@continue@ / \protect\lstinline@break@}{Labelled continue / break}} 803 904 \subsection{\texorpdfstring{Labelled \LstKeywordStyle{continue} / \LstKeywordStyle{break} Statement}{Labelled continue / break Statement}} … … 805 906 While C provides ©continue© and ©break© statements for altering control flow, both are restricted to one level of nesting for a particular control structure. 806 907 Unfortunately, this restriction forces programmers to use \Indexc{goto} to achieve the equivalent control-flow for more than one level of nesting. 807 To prevent having to switch to the ©goto©, \CFA extends the \Indexc{continue}\index{continue@ \lstinline@continue@!labelled}\index{labelled!continue@©continue©} and \Indexc{break}\index{break@\lstinline@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.908 To 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. 808 909 For both ©continue© and ©break©, the target label must be directly associated with a ©for©, ©while© or ©do© statement; 809 910 for ©break©, the target label can also be associated with a ©switch©, ©if© or compound (©{}©) statement. … … 890 991 \end{figure} 891 992 892 Both labelled ©continue© and ©break© are a ©goto©\index{goto@ \lstinline@goto@!restricted} restricted in the following ways:993 Both labelled ©continue© and ©break© are a ©goto©\index{goto@©goto©!restricted} restricted in the following ways: 893 994 \begin{itemize} 894 995 \item … … 1447 1548 \end{cfa} 1448 1549 Algol68 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. 1449 Unfortunately, automatic dereferencing does not work in all cases, and so some mechanism is necessary to fix incorrect choices. 1550 Unfortunately, automatic dereferencing does not work in all cases, and so some mechanism is necessary to fix incorrect choices. 1450 1551 1451 1552 Rather than inferring dereference, most programming languages pick one implicit dereferencing semantics, and the programmer explicitly indicates the other to resolve address-duality. … … 2282 2383 struct T t; 2283 2384 } s; 2284 2385 2285 2386 2286 2387 … … 2354 2455 } 2355 2456 \end{cfa} 2356 because 2457 because 2357 2458 2358 2459 Currently, there are no \Index{lambda} expressions, \ie unnamed routines because routine names are very important to properly select the correct routine. … … 3394 3495 sout | sepDisable | 1 | 2 | 3 | endl; // globally turn off implicit separator 3395 3496 sout | sepEnable | 1 | 2 | 3 | endl; // globally turn on implicit separator 3396 3497 3397 3498 sout | 1 | sepOff | 2 | 3 | endl; // locally turn on implicit separator 3398 3499 sout | sepDisable | 1 | sepOn | 2 | 3 | endl; // globally turn off implicit separator
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