cwebmac.tex

著名算法大师高爷爷设计的语言。此语言结合了Tex和C

% standard macros for CWEB listings (in addition to plain.tex)
% Version 3.65 --- March 2005
\ifx\renewenvironment\undefined\else\endinput\fi % LaTeX will use other macros
\xdef\fmtversion{\fmtversion+CWEB3.65}
\chardef\cwebversion=3 \chardef\cwebrevision=65
\newif\ifpdf
\ifx\pdf+\pdftrue\fi
% Uncomment the following line if you want PDF goodies to be the default
%\ifx\pdf-\else\pdftrue\fi
\def\pdflinkcolor{0 0 1} % the RGB values for hyperlink color
\newif\ifpdftex
\ifx\pdfoutput\undefined \pdftexfalse \else\ifnum\pdfoutput=0 \pdftexfalse
\else \pdftextrue \pdfoutput=1 \input pdfcolor \let\setcolor\pdfsetcolor \fi\fi
\newif\ifacro \ifpdf\acrotrue\fi \ifpdftex\acrotrue\fi

\let\:=\. % preserve a way to get the dot accent
 % (all other accents will still work as usual)

\parskip 0pt % no stretch between paragraphs
\parindent 1em % for paragraphs and for the first line of C text

\font\ninerm=cmr9
\let\mc=\ninerm % medium caps
\def\CEE/{{\mc C\spacefactor1000}}
\def\UNIX/{{\mc U\kern-.05emNIX\spacefactor1000}}
\def\TEX/{\TeX}
\def\CPLUSPLUS/{{\mc C\PP\spacefactor1000}}
\def\Cee{\CEE/} % for backward compatibility
\def\9#1{}
 % with this definition of \9 you can say @:sort key}{TeX code@>
 % to alphabetize an index entry by the sort key but format with the TeX code
\font\eightrm=cmr8
\let\sc=\eightrm % for smallish caps (NOT a caps-and-small-caps font)
\let\mainfont=\tenrm
\let\cmntfont\tenrm
%\font\tenss=cmss10 \let\cmntfont\tenss % alternative comment font
\font\titlefont=cmr7 scaled\magstep4 % title on the contents page
\font\ttitlefont=cmtt10 scaled\magstep2 % typewriter type in title
\font\tentex=cmtex10 % TeX extended character set (used in strings)
\fontdimen7\tentex=0pt % no double space after sentences

\def\\#1{\leavevmode\hbox{\it#1\/\kern.05em}} % italic type for identifiers
\def\|#1{\leavevmode\hbox{$#1$}} % one-letter identifiers look better this way
\def\&#1{\leavevmode\hbox{\bf
  \def\_{\kern.04em\vbox{\hrule width.3em height .6pt}\kern.08em}%
  #1\/\kern.05em}} % boldface type for reserved words
\def\.#1{\leavevmode\hbox{\tentex % typewriter type for strings
  \let\\=\BS % backslash in a string
  \let\{=\LB % left brace in a string
  \let\}=\RB % right brace in a string
  \let\~=\TL % tilde in a string
  \let\ =\SP % space in a string
  \let\_=\UL % underline in a string
  \let\&=\AM % ampersand in a string
  \let\^=\CF % circumflex in a string
  #1\kern.05em}}
\def\){{\tentex\kern-.05em}\discretionary{\hbox{\tentex\BS}}{}{}}
\def\AT{@} % at sign for control text (not needed in versions >= 2.9)
\def\ATL{\par\noindent\bgroup\catcode`\_=12 \postATL} % print @l in limbo
\def\postATL#1 #2 {\bf letter \\{\uppercase{\char"#1}}
   tangles as \tentex "#2"\egroup\par}
\def\noATL#1 #2 {}
\def\noatl{\let\ATL=\noATL} % suppress output from @l
\def\ATH{{\acrofalse\X\kern-.5em:Preprocessor definitions\X}}
\let\PB=\relax % hook for program brackets |...| in TeX part or section name

\chardef\AM=`\& % ampersand character in a string
\chardef\BS=`\\ % backslash in a string
\chardef\LB=`\{ % left brace in a string
\chardef\RB=`\} % right brace in a string
\def\SP{{\tt\char`\ }} % (visible) space in a string
\chardef\TL=`\~ % tilde in a string
\chardef\UL=`\_ % underline character in a string
\chardef\CF=`\^ % circumflex character in a string

\newbox\PPbox % symbol for ++
\setbox\PPbox=\hbox{\kern.5pt\raise1pt\hbox{\sevenrm+\kern-1pt+}\kern.5pt}
\def\PP{\copy\PPbox}
\newbox\MMbox \setbox\MMbox=\hbox{\kern.5pt\raise1pt\hbox{\sevensy\char0
 \kern-1pt\char0}\kern.5pt}
\def\MM{\copy\MMbox}
\newbox\MGbox % symbol for ->
\setbox\MGbox=\hbox{\kern-2pt\lower3pt\hbox{\teni\char'176}\kern1pt}
\def\MG{\copy\MGbox}
\def\MRL#1{\mathrel{\let\K==#1}}
%\def\MRL#1{\KK#1}\def\KK#1#2{\buildrel\;#1\over{#2}}
\let\GG=\gg
\let\LL=\ll
\let\NULL=\Lambda
\mathchardef\AND="2026 % bitwise and; also \& (unary operator)
\let\OR=\mid % bitwise or
\let\XOR=\oplus % bitwise exclusive or
\def\CM{{\sim}} % bitwise complement
\newbox\MODbox \setbox\MODbox=\hbox{\eightrm\%}
\def\MOD{\mathbin{\copy\MODbox}}
\def\DC{\kern.1em{::}\kern.1em} % symbol for ::
\def\PA{\mathbin{.*}} % symbol for .*
\def\MGA{\mathbin{\MG*}} % symbol for ->*
\def\this{\&{this}}

\newbox\bak \setbox\bak=\hbox to -1em{} % backspace one em
\newbox\bakk\setbox\bakk=\hbox to -2em{} % backspace two ems

\newcount\ind % current indentation in ems
\def\1{\global\advance\ind by1\hangindent\ind em} % indent one more notch
\def\2{\global\advance\ind by-1} % indent one less notch
\def\3#1{\hfil\penalty#10\hfilneg} % optional break within a statement
\def\4{\copy\bak} % backspace one notch
\def\5{\hfil\penalty-1\hfilneg\kern2.5em\copy\bakk\ignorespaces}% optional break
\def\6{\ifmmode\else\par % forced break
  \hangindent\ind em\noindent\kern\ind em\copy\bakk\ignorespaces\fi}
\def\7{\Y\6} % forced break and a little extra space
\def\8{\hskip-\ind em\hskip 2em} % no indentation

\newcount\gdepth % depth of current major group, plus one
\newcount\secpagedepth
\secpagedepth=3 % page breaks will occur for depths -1, 0, and 1
\newtoks\gtitle % title of current major group
\newskip\intersecskip \intersecskip=12pt minus 3pt % space between sections
\let\yskip=\smallskip
\def\?{\mathrel?}
\def\note#1#2.{\Y\noindent{\hangindent2em%
    \baselineskip10pt\eightrm#1~\ifacro{\pdfnote#2.}\else#2\fi.\par}}

\newtoks\toksA \newtoks\toksB \newtoks\toksC \newtoks\toksD
\newtoks\toksE \newtoks\toksF \newtoks\usersanitizer
\newcount\countA \countA=0 \newcount\countB \countB=0
\newcount\countC \countC=0
\newif\iftokprocessed \newif\ifTnum \newif\ifinstr
{\def\\{\global\let\spacechar= }\\ }

\ifacro % The following are pdf macros
\def\thewidth{\the\wd0 \space}
\def\theheight{\the\ht\strutbox\space}
\def\thedepth{\the\dp\strutbox\space}
\ifpdftex
  \ifx\pdfannotlink\undefined\let\pdfannotlink\pdfstartlink\fi% for pdfTeX 0.14
  \def\pdflink#1#2{\hbox{\pdfannotlink height\ht\strutbox depth\dp\strutbox
    attr{/Border [0 0 0]} goto num #1 \BlueGreen #1\Black\pdfendlink}}
\else\def\pdflink#1#2{\setbox0=\hbox{\special{pdf: bc [ \pdflinkcolor ]}{#1}%
    \special{pdf: ec}}\special{pdf: ann width \thewidth height \theheight
      depth \thedepth << /Type /Annot /Subtype /Link
      /Border [0 0 0] /A << /S /GoTo /D (#2) >> >>}\box0\relax}\fi
\def\pdfnote#1.{\setbox0=\hbox{\toksA={#1.}\toksB={}\maketoks}\the\toksA}
\def\firstsecno#1.{\setbox0=\hbox{\toksA={#1.}\toksB={}%
    \def\makenote{\addtokens\toksB{\the\toksC}\def\makenote{\toksD={}
      \toksC={}\let\space\empty}\makenote}\maketoks}}
\def\addtokens#1#2{\edef\addtoks{\noexpand#1={\the#1#2}}\addtoks}
\def\poptoks#1#2|ENDTOKS|{\let\first=#1\toksD={#1}%
  \ifcat\noexpand\first0\countB=`#1\else\countB=0\fi\toksA={#2}}
\def\maketoks{\expandafter\poptoks\the\toksA|ENDTOKS|%
  \ifnum\countB>`9 \countB=0 \fi
  \ifnum\countB<`0
    \ifnum0=\countC\else\makenote\fi
    \ifx\first.\let\next=\maketoksdone\else
        \let\next=\maketoks
        \addtokens\toksB{\the\toksD}
        \ifx\first,\addtokens\toksB{\space}\fi
    \fi
  \else \addtokens\toksC{\the\toksD}\global\countC=1\let\next=\maketoks
  \fi
  \next
}
\def\makenote{\addtokens\toksB
    {\noexpand\pdflink{\the\toksC}{\romannumeral\the\toksC}}\toksC={}\global\countC=0}
\def\maketoksdone{\edef\st{\global\noexpand\toksA={\the\toksB}}\st}
\def\pdfURL#1#2{\ifpdftex\pdfannotlink height\ht\strutbox depth\dp\strutbox
  attr {/Border [0 0 0]} user { /Type /Action /Subtype /Link /A
      << /S /URI /URI (#2) >>}\BlueGreen #1\Black \pdfendlink
  \else \ifpdf{\setbox0=\hbox{\special{pdf: bc [ \pdflinkcolor ]}{#1}%
    \special{pdf: ec}}\special{pdf: ann width \thewidth\space height \theheight
      \space depth \thedepth\space << /Border [0 0 0]
      /Type /Action /Subtype /Link /A << /S /URI /URI (#2) >> >>}\box0\relax}%
  \else #1 ({\tt#2})\fi\fi}
{\catcode`\~=12 \gdef\TILDE/{~}} % ~ in a URL
{\catcode`\_=12 \gdef\UNDER/{_}} % _ in a URL
\def\sanitizecommand#1#2{\addtokens\usersanitizer
       {\noexpand\dosanitizecommand\noexpand#1{#2}}}
\def\dosanitizecommand#1#2{\ifx\nxt#1\addF{#2}\fi}

\catcode`\[=1 \catcode`\]=2 \catcode`\{=12 \catcode`\}=12
  \def\lbchar[{]  \def\rbchar[}]
\catcode`\[=12 \catcode`\]=12 \catcode`\{=1 \catcode`\}=2
\catcode`\~=12 \def\tildechar{~}  \catcode`\~=13
\catcode`\|=0 |catcode`|\=12 |def|bschar{\} |catcode`|\=0 \catcode`\|=12
\def\makeoutlinetoks{\Tnumfalse\afterassignment\makeolproctok\let\nxt= }
\def\makeolnexttok{\afterassignment\makeolproctok\let\nxt= }
\def\makeolgobbletok{\afterassignment\makeolnexttok\let\nxt= }
\def\addF#1{\addtokens\toksF{#1}\tokprocessedtrue}
% now comes a routine to "sanitize" section names, for pdf outlines
\def\makeolproctok{\tokprocessedfalse
  \let\next\makeolnexttok % default
  \ifx\nxt\outlinedone\let\next\outlinedone
  \else\ifx{\nxt \else\ifx}\nxt \Tnumfalse \instrfalse % skip braces
  \else\ifx$\nxt % or a $ sign
  \else\ifx^\nxt \addF^\else\ifx_\nxt \addF_% sanitize ^ and _
  \else\ifx\nxt\spacechar \addF\space
  \else\if\noexpand\nxt\relax % we have a control sequence; is it one we know?
    \ifx\nxt~\addF\space
    \else\ifx\nxt\onespace\addF\space
    \else\the\usersanitizer
    \iftokprocessed\else\makeolproctokctli
    \iftokprocessed\else\makeolproctokctlii
    \iftokprocessed\else\makeolproctokctliii % if not recognised, skip it
    \fi\fi\fi\fi\fi
   \else  % we don't have a control sequence, it's an ordinary char
    \ifx/\nxt \addF{\string\/}% quote chars special to PDF with backslash
    \else\ifx(\nxt \addF{\string\(}\else\ifx)\nxt \addF{\string\)}%
    \else\ifx[\nxt \addF{\string\[}\else\ifx]\nxt \addF{\string\]}%
    \else\expandafter\makeolproctokchar\meaning\nxt
   \fi\fi\fi\fi\fi\fi\fi\fi\fi\fi\fi\fi\fi
  \next
}
\def\makeolproctokchar#1 #2 #3{\addF{#3}}
\def\makeolproctokctli{%
  \ifx\nxt\CEE\addF{C}\let\next\makeolgobbletok % \CEE/
  \else\ifx\nxt\UNIX\addF{UNIX}\let\next\makeolgobbletok % \UNIX/
  \else\ifx\nxt\TEX\addF{TeX}\let\next\makeolgobbletok % \TEX/
  \else\ifx\nxt\TeX\addF{TeX}\else\ifx\nxt\LaTeX\addF{LaTeX}%
  \else\ifx\nxt\CPLUSPLUS\addF{C++}\let\next\makeolgobbletok % \CPLUSPLUS/
  \else\ifx\nxt\Cee\addF{C}%
  \else\ifx\nxt\PB \let\next\makeolgobbletok \tokprocessedtrue % \PB{...}
  \else\ifx\nxt\.\tokprocessedtrue\instrtrue % \.{...}
      % skip \|
  \else\ifx\nxt\\\ifinstr\addF{\bschar\bschar}\else\tokprocessedtrue\fi
  \else\ifx\nxt\&\ifinstr\addF&\else\tokprocessedtrue\fi
  \else\ifx\nxt\~\ifTnum\addF{0}\else\addF\tildechar\fi % 077->\T{\~77}
  \else\ifx\nxt\_\ifTnum\addF{E}\else\addF_\fi  % 0.1E5->\T{0.1\_5}
  \else\ifx\nxt\^\ifTnum\addF{0x}\else\addF^\fi  % 0x77 -> \T{\^77}
  \else\ifx\nxt\$\ifTnum\tokprocessedtrue\else\addF$\fi % \T{77\$L}
  \else\ifx\nxt\{\addF\lbchar       \else\ifx\nxt\}\addF\rbchar
  \else\ifx\nxt\ \addF\space        \else\ifx\nxt\#\addF{\string\#}%
  \else\ifx\nxt\PP\addF{++}\else\ifx\nxt\MM\addF{--}%
  \fi\fi\fi\fi\fi\fi\fi\fi\fi\fi\fi\fi\fi\fi\fi\fi\fi\fi\fi\fi\fi
}
\def\makeolproctokctlii{%
  \ifx\nxt\MG\addF{->}\else\ifx\nxt\GG\addF{>>}%
  \else\ifx\nxt\LL\addF{<<}\else\ifx\nxt\NULL\addF{NULL}%
  \else\ifx\nxt\AND\addF&\else\ifx\nxt\OR\addF|%
  \else\ifx\nxt\XOR\addF^\else\ifx\nxt\CM\addF\tildechar
  \else\ifx\nxt\MOD\addF{\string\%}\else\ifx\nxt\DC\addF{::}%
  \else\ifx\nxt\PA\addF{.*}\else\ifx\nxt\MGA\addF{->*}%
  \else\ifx\nxt\this\addF{this}\else\ifx\nxt\?\addF?%
  \else\ifx\nxt\E\addF{==}\else\ifx\nxt\G\addF{>=}%
  \else\ifx\nxt\I\addF{!=}\else\ifx\nxt\K\addF{=}%
  \else\ifx\nxt\l\addF{l}\else\ifx\nxt\L\addF{L}%
  \else\ifx\nxt\o\addF{o}\else\ifx\nxt\O\addF{O}%
  \else\ifx\nxt\R\addF!%
  \else\ifx\nxt\T \Tnumtrue \let\next\makeolgobbletok
    \tokprocessedtrue % \T{number}
  \else\ifx\nxt\AM\addF&\else\ifx\nxt\%\addF{\string\%}%
  \fi\fi\fi\fi\fi \fi\fi\fi\fi\fi
  \fi\fi\fi\fi\fi \fi\fi\fi\fi\fi
  \fi\fi\fi\fi\fi\fi
}
\def\makeolproctokctliii{%
  \ifx\nxt\V\addF{||}\else\ifx\nxt\W\addF{&&}\else\ifx\nxt\Z\addF{<=}%
  \else\ifx\nxt\*\addF*\else\ifx\nxt\Xand\addF{\space and\space}%
  \else\ifx\nxt\Xandxeq\addF{\space and_eq\space}%
  \else\ifx\nxt\Xbitand\addF{\space bitand\space}%
  \else\ifx\nxt\Xbitor\addF{\space bitor\space}%
  \else\ifx\nxt\Xcompl\addF{\space compl\space}%
  \else\ifx\nxt\Xnot\addF{\space not\space}%
  \else\ifx\nxt\Xnotxeq\addF{\space not_eq\space}%
  \else\ifx\nxt\Xor\addF{\space or\space}%
  \else\ifx\nxt\Xorxeq\addF{\space or_eq\space}%
  \else\ifx\nxt\Xxor\addF{\space xor\space}%
  \else\ifx\nxt\Xxorxeq\addF{\space xor_eq\space}%
  \fi\fi\fi\fi\fi\fi\fi\fi\fi\fi
  \fi\fi\fi\fi\fi