chiark - git - mdw - become/blob - manual/syntax.sty

   1 %%
   2 %% This is file `syntax.sty',
   3 %% generated with the docstrip utility.
   4 %%
   5 %% The original source files were:
   6 %%
   7 %% syntax.dtx  (with options: `package')
   8 %% doafter.dtx  (with options: `macro')
   9 %%
  10 %% IMPORTANT NOTICE
  11 %%
  12 %% syntax package -- typesetting syntax descriptions
  13 %% Copyright (c) 1996 Mark Wooding
  14 %%
  15 %% This program is free software; you can redistribute it and/or modify
  16 %% it under the terms of the GNU General Public License as published by
  17 %% the Free Software Foundation; either version 2 of the License, or
  18 %% (at your option) any later version.
  19 %%
  20 %% This program is distributed in the hope that it will be useful,
  21 %% but WITHOUT ANY WARRANTY; without even the implied warranty of
  22 %% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23 %% GNU General Public License for more details.
  24 %%
  25 %% You should have received a copy of the GNU General Public License
  26 %% along with this program; if not, write to the Free Software
  27 %% Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  28 %%
  29 \NeedsTeXFormat{LaTeX2e}
  30 \ProvidesPackage{syntax}
  31                 [1996/05/17 1.9 Syntax typesetting (MDW)]
  32 %% \CharacterTable
  33 %%  {Upper-case    \A\B\C\D\E\F\G\H\I\J\K\L\M\N\O\P\Q\R\S\T\U\V\W\X\Y\Z
  34 %%   Lower-case    \a\b\c\d\e\f\g\h\i\j\k\l\m\n\o\p\q\r\s\t\u\v\w\x\y\z
  35 %%   Digits        \0\1\2\3\4\5\6\7\8\9
  36 %%   Exclamation   \!     Double quote  \"     Hash (number) \#
  37 %%   Dollar        \$     Percent       \%     Ampersand     \&
  38 %%   Acute accent  \'     Left paren    \(     Right paren   \)
  39 %%   Asterisk      \*     Plus          \+     Comma         \,
  40 %%   Minus         \-     Point         \.     Solidus       \/
  41 %%   Colon         \:     Semicolon     \;     Less than     \<
  42 %%   Equals        \=     Greater than  \>     Question mark \?
  43 %%   Commercial at \@     Left bracket  \[     Backslash     \\
  44 %%   Right bracket \]     Circumflex    \^     Underscore    \_
  45 %%   Grave accent  \`     Left brace    \{     Vertical bar  \|
  46 %%   Right brace   \}     Tilde         \~}
  47 %%
  48 \DeclareOption{rounded}{\sd@roundtrue}
  49 \DeclareOption{square}{\sd@roundfalse}
  50 \DeclareOption{nounderscore}{\@uscorefalse}
  51 \newif\ifsd@round
  52 \newif\if@uscore\@uscoretrue
  53 \ExecuteOptions{square}
  54 \ProcessOptions
  55 \def\addspecial#1{%
  56   \remspecial{#1}%
  57   \expandafter\def\expandafter\dospecials\expandafter{\dospecials\do#1}%
  58   \expandafter\def\expandafter\@santize\expandafter{%
  59     \@sanitize\@makeother#1}%
  60 }
  61 \def\remspecial#1{%
  62   \def\do##1{\ifnum`#1=`##1 \else\noexpand\do\noexpand##1\fi}%
  63   \edef\dospecials{\dospecials}%
  64   \def\@makeother##1{\ifnum`#1=`##1 \else%
  65     \noexpand\@makeother\noexpand##1\fi}%
  66   \edef\@sanitize{\@sanitize}%
  67   \def\@makeother##1{\catcode`##112}%
  68 }
  69 \def\underscore{%
  70   \leavevmode%
  71   \kern.06em%
  72   \vbox{%
  73     \hrule\@width.6em\@depth.4ex\@height-.34ex%
  74   }%
  75   \ifdim\fontdimen\@ne\font=\z@%
  76     \kern.06em%
  77   \fi%
  78 }
  79 \let\usc@builtindischyphen\-
  80 \def\@uscore.{%
  81   \ifmmode%
  82     \expandafter\@firstoftwo%
  83   \else%
  84     \expandafter\@secondoftwo%
  85   \fi%
  86   \sb%
  87   {\textunderscore\@ifnextchar_{}{\usc@builtindischyphen}}%
  88 }
  89 \if@uscore
  90   \AtBeginDocument{%
  91     \catcode`\_\active%
  92     \begingroup%
  93     \lccode`\~`\_%
  94     \lowercase{\endgroup\def~{\protect\@uscore.}}%
  95   }
  96 \fi
  97 \expandafter\let\csname?\string\textunderscore\endcsname\underscore
  98 \def\shortverb#1{%
  99   \@ifundefined{cc@\string#1}{%
 100     \addspecial#1%
 101     \begingroup%
 102     \lccode`\~`#1%
 103     \lowercase{%
 104       \endgroup%
 105       \expandafter\let\csname mn@\string#1\endcsname~%
 106       \expandafter\edef\csname cc@\string#1\endcsname{%
 107         \catcode`\noexpand#1\the\catcode`#1%
 108         \let\noexpand~\expandafter\noexpand%
 109           \csname mn@\string#1\endcsname%
 110         \noexpand\remspecial\noexpand#1%
 111         \let\csname cc@\string#1\endcsname\relax%
 112       }%
 113       \def~{\verb~\syn@ttspace}%
 114     }%
 115     \catcode`#1\active%
 116   }{%
 117     \PackageWarning{syntax}{Character `\expandafter\@gobble\string#1'
 118                             is already a verbatim\MessageBreak
 119                             delimiter}%
 120   }%
 121 }
 122 \def\unverb#1{%
 123   \@ifundefined{cc@\string#1}{%
 124     \PackageWarning{syntax}{Character `\expandafter\@gobble\string#1'
 125                             is not a verbatim\MessageBreak
 126                             delimiter}%
 127   }{%
 128     \csname cc@\string#1\endcsname%
 129   }%
 130 }
 131 \newcommand{\syntleft}{$\langle$\normalfont\itshape}
 132 \newcommand{\syntright}{$\rangle$}
 133 \newcommand{\ulitleft}{\normalfont\ttfamily\syn@ttspace\frenchspacing}
 134 \newcommand{\ulitright}{}
 135 \newcommand{\litleft}{`\bgroup\ulitleft}
 136 \newcommand{\litright}{\ulitright\egroup'}
 137 \def\synt#1{\mbox{\syntleft{#1\/}\syntright}}
 138 \def\lit{\@ifstar{\lit@i\ulitleft\ulitright}{\lit@i\litleft\litright}}
 139 \def\lit@i#1#2#3{\mbox{#1{#3\/}#2}}
 140 \def\syn@ttspace@{\spaceskip.35em\@plus.2em\@minus.15em\relax}
 141 \def\ttthinspace{\let\syn@ttspace\syn@ttspace@}
 142 \def\ttthickspace{\let\syn@ttspace\@empty}
 143 \ttthinspace
 144 \def\readupto#1#2#3{%
 145   \bgroup%
 146   \verb@eol@error%
 147   \let\do\@makeother\dospecials%
 148   #2%
 149   \catcode`#1\active%
 150   \lccode`\~`#1%
 151   \gdef\verb@balance@group{\verb@egroup%
 152      \@latex@error{\noexpand\verb illegal in command argument}\@ehc}%
 153   \def\@vhook{\verb@egroup#3}%
 154   \aftergroup\verb@balance@group%
 155   \lowercase{\let~\@vhook}%
 156 }
 157 \def\syn@assist#1#2#3#4#5{%
 158   \mbox\bgroup%
 159   \chardef\\`\\%
 160   \chardef\>`\>%
 161   \chardef\'`\'%
 162   \chardef\"`\"%
 163   \chardef\ `\ %
 164   \def\ch##1{\char`##1}%
 165   \def\act##1{%
 166     \catcode`##1\active%
 167     \begingroup%
 168     \lccode`\~`##1%
 169     \lowercase{\endgroup\def~}%
 170   }%
 171   #1%
 172   \begingroup%
 173   \readupto#3{%
 174     \catcode`\\0%
 175     \catcode`\ 10%
 176     #2%
 177   }{%
 178     \/\endgroup#4\egroup#5%
 179   }%
 180 }
 181 \begingroup
 182 \catcode`\<\active
 183 \catcode`\|\active
 184 \catcode`\"\active
 185 \catcode`\`\active
 186 \gdef\syn@shorts#1#2{%
 187   \def<{%
 188     #1%
 189     \syn@assist%
 190       \syntleft%
 191       {\act_{\@foundunderscore}}%
 192       >%
 193       \syntright%
 194       {#2}%
 195   }%
 196   \def`{%
 197     #1%
 198     \syn@assist%
 199       \litleft%
 200       \relax%
 201       '%
 202       \litright%
 203       {#2}%
 204   }%
 205   \def"{%
 206     #1%
 207     \syn@assist%
 208       \ulitleft%
 209       \relax%
 210       "%
 211       \ulitright%
 212       {#2}%
 213   }%
 214   \def|{\textbar}%
 215 }
 216 \endgroup
 217 \def\syntaxShortcuts#1#2{%
 218   \syn@shorts{#1}{#2}%
 219   \addspecial\`%
 220   \addspecial\<%
 221   \addspecial\|%
 222   \addspecial\"%
 223   \catcode`\|\active%
 224   \catcode`\<\active%
 225   \catcode`\"\active%
 226   \catcode`\`\active%
 227 }
 228 \def\synshorts{\syntaxShortcuts\relax\relax}
 229 \def\synshortsoff{%
 230   \catcode`\|12%
 231   \catcode`\<12%
 232   \catcode`\"12%
 233   \catcode`\`12%
 234 }
 235 \def\syntax#{\bgroup\syntaxShortcuts\relax\relax\let\@let@token}
 236 \newskip\grammarparsep
 237   \grammarparsep8\p@\@plus\p@\@minus\p@
 238 \newdimen\grammarindent
 239   \grammarindent2em
 240 \newcommand{\grammarlabel}[2]{%
 241   \synt{#1} \hfill#2%
 242 }
 243 \def\gr@implitem<#1> #2 {%
 244   \sbox\z@{\hskip\labelsep\grammarlabel{#1}{#2}}%
 245   \strut\@@par%
 246   \vskip-\parskip%
 247   \vskip-\baselineskip%
 248   \hrule\@height\z@\@depth\z@\relax%
 249   \item[\unhbox\z@]%
 250   \catcode`\<\active%
 251 }
 252 \let\gr@leftsq\[
 253 \let\gr@rightsq\]
 254 \def\[{\gr@leftsq}
 255 \def\]{\gr@rightsq}
 256 \newenvironment{grammar}{%
 257   \list{}{%
 258     \labelwidth\grammarindent%
 259     \leftmargin\grammarindent%
 260     \advance\grammarindent\labelsep
 261     \itemindent\z@%
 262     \listparindent\z@%
 263     \parsep\grammarparsep%
 264   }%
 265   \let\\\@normalcr
 266   \syntaxShortcuts\relax\relax%
 267   \def\alt{\\\llap{\textbar\quad}}%
 268   \def\gr@setpar{%
 269     \def\par{%
 270       \parshape\@ne\@totalleftmargin\linewidth%
 271       \@@par%
 272       \catcode`\<12%
 273       \everypar{%
 274         \everypar{}%
 275         \catcode`\<\active%
 276         \gr@implitem%
 277       }%
 278     }%
 279   }%
 280   \gr@setpar%
 281   \par%
 282   \def\gr@endsyntdiag]{\end{syntdiag}\gr@setpar\par}%
 283   \def\[{\@ifnextchar[{\begin{syntdiag}\@gobble}\gr@leftsq}%
 284   \def\]{\@ifnextchar]\gr@endsyntdiag\gr@rightsq}%
 285 }{%
 286   \@newlistfalse%
 287   \everypar{}%
 288   \endlist%
 289 }
 290 \newskip\sdstartspace
 291 \newskip\sdendspace
 292 \newskip\sdmidskip
 293 \newskip\sdtokskip
 294 \newskip\sdfinalskip
 295 \newdimen\sdrulewidth
 296 \newdimen\sdcirclediam
 297 \newdimen\sdindent
 298 \dimendef\sd@lower\z@
 299 \dimendef\sd@upper\tw@
 300 \dimendef\sd@mid4
 301 \dimendef\sd@topcirc6
 302 \dimendef\sd@botcirc8
 303 \def\sd@setsize{%
 304   \sd@mid\ht\strutbox%
 305   \advance\sd@mid-\dp\strutbox%
 306   \sd@mid.5\sd@mid%
 307   \sd@upper\sdrulewidth%
 308     \advance\sd@upper\sd@mid%
 309   \sd@lower\sdrulewidth%
 310     \advance\sd@lower-\sd@mid%
 311   \sd@topcirc-.5\sdcirclediam%
 312     \advance\sd@topcirc\sd@mid%
 313   \sd@botcirc-.5\sdcirclediam%
 314     \advance\sd@botcirc-\sd@mid%
 315 }
 316 \newcommand{\sdsize}{%
 317   \small%
 318 }
 319 \newcommand{\sdlengths}{%
 320   \setlength{\sdstartspace}{1em minus 10pt}%
 321   \setlength{\sdendspace}{1em minus 10pt}%
 322   \setlength{\sdmidskip}{0.5em plus 0.0001fil}%
 323   \setlength{\sdtokskip}{0.25em plus 0.0001fil}%
 324   \setlength{\sdfinalskip}{0.5em plus 10000fil}%
 325   \setlength{\sdrulewidth}{0.2pt}%
 326   \setlength{\sdcirclediam}{8pt}%
 327   \setlength{\sdindent}{0pt}%
 328 }
 329 \newif\ifsd@base
 330 \newif\ifsd@top
 331 \newif\ifsd@toplayer
 332 \newif\ifsd@backwards
 333 \def\sd@err{\PackageError{syntax}}
 334 \def\sd@arrow{%
 335   \ht\tw@\z@%
 336   \dp\tw@\z@%
 337   \raise\sd@mid\box\tw@%
 338   \egroup%
 339 }
 340 \def\sd@rightarr{%
 341   \bgroup%
 342   \setbox\tw@\hbox{\kern-6\p@\@linefnt\char'55}%
 343   \sd@arrow%
 344 }
 345 \def\sd@leftarr{%
 346   \bgroup%
 347   \raise\sd@mid\hbox{\@linefnt\char'33\kern-6\p@}%
 348   \sd@arrow%
 349 }
 350 \def\sd@uparr{%
 351   \bgroup%
 352   \setbox\tw@\hb@xt@\z@{\kern-\sdrulewidth\@linefnt\char'66\hss}%
 353   \setbox\tw@\hbox{\lower10\p@\box\tw@}%
 354   \sd@arrow%
 355 }
 356 \def\sd@downarr{%
 357   \bgroup%
 358   \setbox\tw@\hb@xt@\z@{\kern-\sdrulewidth\@linefnt\char'77\hss}%
 359   \sd@arrow%
 360 }
 361 \def\sd@circ#1{%
 362   \@getcirc\sdcirclediam%
 363   \advance\@tempcnta#1%
 364   \setbox\tw@\hbox{\lower\sdrulewidth%
 365     \hbox{\@circlefnt\char\@tempcnta}}%
 366   \wd\tw@\z@%
 367   \leavevmode%
 368 }
 369 \def\sd@tlcirc{{%
 370   \sd@circ3%
 371   \ht\tw@\sdrulewidth%
 372   \dp\tw@.5\sdcirclediam%
 373   \kern-\tw@\sdrulewidth%
 374   \raise\sd@mid\box\tw@%
 375   \kern.5\sdcirclediam%
 376 }}
 377 \def\sd@trcirc{{%
 378   \sd@circ0%
 379   \ht\tw@\sdrulewidth%
 380   \dp\tw@.5\sdcirclediam%
 381   \kern.5\sdcirclediam%
 382   \raise\sd@mid\box\tw@%
 383 }}
 384 \def\sd@blcirc{{%
 385   \sd@circ2%
 386   \ht\tw@.5\sdcirclediam%
 387   \dp\tw@\sdrulewidth%
 388   \kern-\tw@\sdrulewidth%
 389   \raise\sd@mid\box\tw@%
 390   \kern.5\sdcirclediam%
 391 }}
 392 \def\sd@brcirc{{%
 393   \sd@circ1%
 394   \ht\tw@.5\sdcirclediam%
 395   \dp\tw@\sdrulewidth%
 396   \kern.5\sdcirclediam%
 397   \raise\sd@mid\box\tw@%
 398 }}
 399 \def\sd@llc#1{%
 400   \hb@xt@.5\sdcirclediam{%
 401     \sd@rule\hskip.5\sdcirclediam%
 402     \hss%
 403     #1%
 404   }%
 405 }
 406 \def\sd@rlc#1{%
 407   \hb@xt@.5\sdcirclediam{%
 408     #1%
 409     \hss%
 410     \sd@rule\hskip.5\sdcirclediam%
 411   }%
 412 }
 413 \def\sd@rule{\leaders\hrule\@height\sd@upper\@depth\sd@lower}
 414 \def\sd@gap#1{%
 415   \ifsd@base%
 416     \skip@#1%
 417       \divide\skip\z@\tw@%
 418     \nobreak\sd@rule\hskip\skip@%
 419     \discretionary{%
 420       \sd@qarrow{->}%
 421     }{%
 422       \hbox{%
 423         \sd@qarrow{>-}%
 424         \sd@rule\hskip\sdstartspace%
 425         \sd@rule\hskip3.5\p@%
 426       }%
 427     }{%
 428     }%
 429     \nobreak\sd@rule\hskip\skip@%
 430   \else%
 431     \sd@rule\hskip#1%
 432   \fi%
 433 }
 434 \def\syntdiag{%
 435   \syntaxShortcuts\sd@tok@i\sd@tok@ii%
 436   \@ifnextchar[\syntdiag@i{\syntdiag@i[]}%
 437 }
 438 \def\syntdiag@i[#1]{%
 439   \sdsize\sdlengths%
 440   #1%
 441   \sd@setsize%
 442   \list{}{%
 443     \leftmargin\sdindent%
 444     \rightmargin\leftmargin%
 445     \labelsep\z@%
 446     \labelwidth\z@%
 447   }%
 448   \item[]%
 449   \parfillskip\z@%
 450   \noindent%
 451   \sd@qarrow{>>-}%
 452   \nobreak\sd@rule\hskip\sdstartspace%
 453   \sd@basetrue%
 454   \sloppy%
 455   \interlinepenalty100%
 456   \hyphenpenalty0%
 457   \catcode`\ 9%
 458   \catcode`\^^M9%
 459   \def\gr@leftsq{\begin{stack}\\}%
 460   \def\gr@rightsq{\end{stack}}%
 461   \def\({\begin{stack}}%
 462   \def\){\end{stack}}%
 463   \def\<{\begin{rep}}%
 464   \def\>{\end{rep}}%
 465   \let\\\sd@newline%
 466   \ignorespaces%
 467 }
 468 \def\endsyntdiag{%
 469   \unskip%
 470   \nobreak\sd@rule\hskip\sdmidskip%
 471   \sd@rule\hskip\sdfinalskip%
 472   \sd@qarrow{-><}%
 473   \endlist%
 474 }
 475 \@namedef{syntdiag*}{%
 476   \syntaxShortcuts\sd@tok@i\sd@tok@ii%
 477   \@ifnextchar[\syntdiag@s@i{\syntdiag@s@i[]}%
 478 }
 479 \def\syntdiag@s@i[#1]{%
 480   \@ifnextchar[{\syntdiag@s@ii{#1}}{\syntdiag@s@iii{#1}{\hbox}}%
 481 }
 482 \def\syntdiag@s@ii#1[#2]{\syntdiag@s@iii{#1}{\hb@xt@#2}}
 483 \def\syntdiag@s@iii#1#2{%
 484   \leavevmode%
 485   #2\bgroup%
 486   \let\@@left\left%
 487   \let\@@right\right%
 488   \def\left##1{\def\sd@startarr{##1}}%
 489   \def\right##1{\def\sd@endarr{##1}}%
 490   \left{>-}\right{->}%
 491   \sdsize\sdlengths%
 492   #1%
 493   \sd@setsize%
 494   \let\left\@@left%
 495   \let\right\@@right%
 496   \sd@qarrow\sd@startarr%
 497   \sd@rule\hskip\sdmidskip%
 498   \sd@basefalse%
 499   \catcode`\ 9%
 500   \catcode`\^^M9%
 501   \ignorespaces%
 502 }
 503 \@namedef{endsyntdiag*}{%
 504   \unskip%
 505   \sd@rule\hskip\sdmidskip%
 506   \sd@rule\hskip\sdfinalskip%
 507   \sd@qarrow\sd@endarr%
 508   \egroup%
 509 }
 510 \def\sd@qarrow#1{%
 511   \begingroup%
 512   \lccode`\~=`\<\lowercase{\def~{<}}%
 513   \hbox{\csname sd@arr@#1\endcsname}%
 514   \endgroup%
 515 }
 516 \@namedef{sd@arr@>>-}{\sd@rightarr\kern-.5\p@\sd@rightarr\kern-\p@}
 517 \@namedef{sd@arr@>-}{\sd@rightarr\kern-\p@}
 518 \@namedef{sd@arr@->}{\sd@rightarr}
 519 \@namedef{sd@arr@-><}{\sd@rightarr\kern-\p@\sd@leftarr}
 520 \@namedef{sd@arr@...}{$\cdots$}
 521 \@namedef{sd@arr@-}{}
 522 \def\sd@newline{\@ifstar{\vadjust{\penalty\@M}\sd@nl@i}\sd@nl@i}
 523 \def\sd@nl@i{\@ifnextchar[\sd@nl@ii\sd@nl@iii}
 524 \def\sd@nl@ii[#1]{\vspace{#1}\sd@nl@iii}
 525 \def\sd@nl@iii{%
 526   \nobreak\sd@rule\hskip\sdmidskip%
 527   \sd@rule\hskip\sdfinalskip%
 528   \kern-3\p@%
 529   \sd@rightarr%
 530   \newline%
 531   \sd@rightarr%
 532   \nobreak\sd@rule\hskip\sdstartspace%
 533   \sd@rule\hskip3.5\p@%
 534 }
 535 \def\sdbox#1{%
 536   \@tempskipa#1\relax%
 537   \sd@gap\@tempskipa%
 538   \setbox\z@\hbox\bgroup%
 539     \begingroup%
 540     \catcode`\ 10%
 541     \catcode`\^^M5%
 542     \synshortsoff%
 543 }
 544 \def\endsdbox{%
 545     \endgroup%
 546   \egroup%
 547   \@tempdima\ht\z@%
 548   \advance\@tempdima-\dp\z@%
 549   \advance\@tempdima-\tw@\sd@mid%
 550   \lower.5\@tempdima\box\z@%
 551   \sd@gap\@tempskipa%
 552 }
 553 \def\sd@tok@i{%
 554   \sdbox\sdtokskip%
 555   \strut%
 556   \space%
 557 }
 558 \def\sd@tok@ii{%
 559   \space%
 560   \endsdbox%
 561 }
 562 \def\tok#{%
 563   \sdbox\sdtokskip%
 564   \strut%
 565   \enspace%
 566   \syntaxShortcuts\relax\relax%
 567   \doafter\sd@tok%
 568 }
 569 \def\sd@tok{%
 570   \enspace%
 571   \endsdbox%
 572 }
 573 \newcommand\stack[1][t]{%
 574   \sd@gap\sdmidskip%
 575   \begingroup\sd@basefalse%
 576   \sd@toplayertrue%
 577   \let\\\sd@stackcr%
 578   \if#1t%
 579     \let\@tempa\vtop%
 580     \sd@toptrue%
 581     \ifsd@round\llap{\sd@trcirc\kern\tw@\sdrulewidth}\fi%
 582   \else\if#1b%
 583     \let\@tempa\vbox%
 584     \sd@topfalse%
 585     \ifsd@round\llap{\sd@brcirc\kern\tw@\sdrulewidth}\fi%
 586   \else%
 587     \sd@err{Bad position argument passed to stack}%
 588            {The positioning argument must be one of `t' or `b'.  I%
 589             have^^Jassumed you meant to type `t'.}%
 590     \let\@tempa\vtop%
 591   \fi\fi%
 592   \@tempa\bgroup%
 593   \offinterlineskip%
 594   \ialign\bgroup%
 595     ##\cr%
 596   \setbox\z@\hbox\bgroup%
 597     \strut%
 598 }
 599 \def\endstack{%
 600   \egroup%
 601   \ifsd@toplayer%
 602     \sd@dostack\sd@upper\sd@lower\relax\relax%
 603   \else%
 604     \ifsd@round%
 605       \ifsd@top%
 606         \sd@dostack{\ht\z@}\sd@botcirc\sd@blcirc\sd@brcirc%
 607       \else%
 608         \sd@dostack{\ht\z@}\sd@botcirc\relax\relax%
 609       \fi%
 610     \else%
 611       \sd@dostack{\ht\z@}\sd@lower\relax\relax%
 612     \fi%
 613   \fi%
 614   \egroup%
 615   \egroup%
 616   \ifsd@round%
 617     \ifsd@top
 618       \rlap{\kern\tw@\sdrulewidth\sd@tlcirc}%
 619     \else%
 620       \rlap{\kern\tw@\sdrulewidth\sd@blcirc}%
 621     \fi%
 622   \fi%
 623   \endgroup\sd@gap\sdmidskip%
 624 }
 625 \def\sd@stackcr{%
 626   \egroup%
 627   \ifsd@toplayer%
 628     \ifsd@round%
 629       \ifsd@top%
 630         \sd@dostack\sd@topcirc{\dp\z@}\relax\relax%
 631       \else%
 632         \sd@dostack\sd@topcirc{\dp\z@}\sd@tlcirc\sd@trcirc%
 633       \fi%
 634     \else%
 635       \sd@dostack\sd@upper{\dp\z@}\relax\relax%
 636     \fi%
 637   \else%
 638     \ifsd@round%
 639       \ifsd@top%
 640         \sd@dostack{\ht\z@}{\dp\z@}\sd@blcirc\sd@brcirc%
 641       \else%
 642         \sd@dostack{\ht\z@}{\dp\z@}\sd@tlcirc\sd@trcirc%
 643       \fi%
 644     \else%
 645       \sd@dostack{\ht\z@}{\dp\z@}\relax\relax%
 646     \fi%
 647   \fi%
 648   \sd@toplayerfalse%
 649   \setbox\z@\hbox\bgroup%
 650     \strut%
 651 }
 652 \def\sd@dostack#1#2#3#4{%
 653   \@tempdima#1%
 654   \@tempdimb#2%
 655   \kern-\tw@\sdrulewidth%
 656   \vrule\@height\@tempdima\@depth\@tempdimb\@width\tw@\sdrulewidth%
 657   #3%
 658   \sd@rule\hfill%
 659   \sd@gap\sdtokskip%
 660   \unhbox\z@%
 661   \sd@gap\sdtokskip%
 662   \sd@rule\hfill%
 663   #4%
 664   \vrule\@height\@tempdima\@depth\@tempdimb\@width\tw@\sdrulewidth%
 665   \kern-\tw@\sdrulewidth%
 666   \cr%
 667 }
 668 \newcommand\rep[1][t]{%
 669   \sd@gap\sdmidskip%
 670   \begingroup\sd@basefalse%
 671   \ifsd@backwards\sd@backwardsfalse\else\sd@backwardstrue\fi%
 672    \let\\\sd@loop%
 673   \if#1t%
 674     \let\@tempa\vbox%
 675     \sd@toptrue%
 676   \else\if#1b%
 677     \let\@tempa\vtop%
 678     \sd@topfalse%
 679   \else%
 680     \sd@err{Bad position argument passed to loop}%
 681            {The positioning argument must be `t' or `b'.  I have^^J%
 682             assumed you meant to type `t'.}%
 683     \let\@tempa\vbox%
 684     \sd@toptrue%
 685   \fi\fi%
 686   \@tempa\bgroup%
 687   \setbox\tw@\copy\strutbox%
 688   \setbox\z@\hbox\bgroup\strut%
 689 }
 690 \def\endrep{%
 691   \egroup%
 692   \ifsd@top%
 693     \ifsd@round%
 694       \sd@doloop\tw@\z@\relax\relax%
 695         \sd@tlcirc\sd@trcirc{\sd@rlc\sd@blcirc}{\sd@llc\sd@brcirc}%
 696     \else%
 697       \sd@doloop\tw@\z@\relax\sd@downarr\relax\relax\relax\relax%
 698     \fi%
 699   \else%
 700     \ifsd@round%
 701       \sd@doloop\z@\tw@\relax\relax%
 702         {\sd@rlc\sd@tlcirc}{\sd@llc\sd@trcirc}\sd@blcirc\sd@brcirc%
 703     \else%
 704       \sd@doloop\z@\tw@\sd@uparr\relax\relax\relax\relax\relax%
 705     \fi%
 706   \fi%
 707   \egroup%
 708   \endgroup\sd@gap\sdmidskip%
 709 }
 710 \def\sd@loop{%
 711   \egroup%
 712   \def\\{\sd@err{Too many \string\\\space commands in loop}\@ehc}%
 713   \setbox\tw@\hbox\bgroup\strut%
 714 }
 715 \def\sd@doloop#1#2#3#4#5#6#7#8{%
 716   \@tempdima\dp#1\relax%
 717   \@tempdimb\ht#2\relax%
 718   \offinterlineskip%
 719   \ialign{%
 720     ##\cr%
 721     \ifsd@round%
 722       \sd@doloop@i#1#3\sd@topcirc\@tempdima{#5}{#6}%
 723       \sd@doloop@i#2#4\@tempdimb\sd@botcirc{#7}{#8}%
 724     \else%
 725       \sd@doloop@i#1#3\sd@upper\@tempdima{#5}{#6}%
 726       \sd@doloop@i#2#4\@tempdimb\sd@lower{#7}{#8}%
 727     \fi%
 728   }%
 729 }
 730 \def\sd@doloop@i#1#2#3#4#5#6{%
 731   \ifsd@backwards#2\fi%
 732   \kern-\tw@\sdrulewidth%
 733   \vrule\@height#3\@depth#4\@width\tw@\sdrulewidth%
 734   #5%
 735   \sd@rule\hfill%
 736   \sd@gap\sdtokskip%
 737   \unhbox#1%
 738   \sd@gap\sdtokskip%
 739   \sd@rule\hfill%
 740   #6%
 741   \vrule\@height#3\@depth#4\@width\tw@\sdrulewidth%
 742   \ifsd@backwards\else#2\fi%
 743   \kern-\tw@\sdrulewidth%
 744   \cr%
 745 }
 746 %%
 747 %% doafter package -- insert a token really after a group
 748 %% Copyright (c) 1996 Peter Schmitt and Mark Wooding
 749 %%
 750 \let\@@aftergroup\aftergroup
 751 \def\doafter#1{%
 752   \def\@tempa{\@@aftergroup#1}%
 753   \afterassignment\doafter@i\let\@let@token%
 754 }
 755 \def\doafter@i{%
 756   \@let@token%
 757   \let\aftergroup\@my@aftergroup%
 758   \@@aftergroup\@prepare@after\@tempa%
 759 }
 760 \def\ag@cnt@local{0 }
 761 \let\ag@cnt@global\ag@cnt@local
 762 \def\@my@aftergroup{%
 763   \begingroup%
 764     \count@\ag@cnt@local%
 765     \advance\count@\@ne%
 766     \xdef\ag@cnt@global{\the\count@\space}%
 767   \endgroup%
 768   \let\ag@cnt@local\ag@cnt@global%
 769   \@@aftergroup\@after@token\@@aftergroup%
 770 }
 771 \def\@after@token{%
 772   \@start@after@group%
 773   \@after@token%
 774 }
 775 \def\@start@after@group{%
 776   \begingroup%
 777   \count@\ag@cnt@global%
 778   \clubpenalty\ag@cnt@local%
 779   \let\@after@token\@after@token@i%
 780 }
 781 \def\@after@token@i{%
 782   \advance\count@\m@ne%
 783   \ifnum\count@=\clubpenalty%
 784     \global\let\ag@cnt@global\ag@cnt@local%
 785     \expandafter\@after@aftertoken\expandafter\@after@all%
 786   \else%
 787     \expandafter\@@aftergroup%
 788   \fi%
 789 }
 790 \let\@after@all\endgroup
 791 \def\@prepare@after{%
 792   \ifx\ag@cnt@local\ag@cnt@global\else%
 793     \expandafter\@prepare@after@i%
 794   \fi%
 795 }
 796 \def\@prepare@after@i#1{%
 797   \@start@after@group%
 798   \def\@after@all{\@@aftergroup#1\endgroup}%
 799 }
 800 \def\@after@aftertoken#1{%
 801   \let\bgroup\relax\let\egroup\relax%
 802   \toks@{#1}%
 803   \futurelet\@let@token\@after@aftertoken@i%
 804 }
 805 \def\@after@aftertoken@i{%
 806   \ifcat\noexpand\@let@token{%
 807     \@@aftergroup{%
 808   \else\ifcat\noexpand\@let@token}%
 809     \@@aftergroup}%
 810   \else%
 811     \def\@tempa##1{\@@aftergroup##1\the\toks@}%
 812     \expandafter\expandafter\expandafter\@tempa%
 813   \fi\fi%
 814 }
 815 \endinput
 816 %%
 817 %% End of file `syntax.sty'.