294 lines
12 KiB
TeX
294 lines
12 KiB
TeX
% code.sty: -*- latex -*-
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% Latex macros for a "weak" verbatim mode.
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% -- like verbatim, except \, {, and } have their usual meanings.
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% Environments: code, tightcode, codeaux, codebox, centercode
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% Commands: \dcd, \cddollar, \cdmath, \cd, \codeallowbreaks, \codeskip, \^
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% Already defined in LaTeX, but of some relevance: \#, \$, \%, \&, \_, \{, \}
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% Changelog at the end of the file.
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% These commands give you an environment, code, that is like verbatim
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% except that you can still insert commands in the middle of the environment:
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% \begin{code}
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% for(x=1; x<loop_bound; x++)
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% y += x^3; /* {\em Add in {\tt x} cubed} */
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% \end{code}
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%
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% All characters are ordinary except \{}. To get \{} in your text,
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% you use the commands \\, \{, and \}.
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% These macros mess with the definition of the special chars (e.g., ^_~%).
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% The characters \{} are left alone, so you can still have embedded commands:
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% \begin{code} f(a,b,\ldots,y,z) \end{code}
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% However, if your embedded commands use the formerly-special chars, as in
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% \begin{code} x := x+1 /* \mbox{\em This is $y^3$} */ \end{code}
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% then you lose. The $ and ^ chars are scanned in as non-specials,
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% so they don't work. If the chars are scanned *outside* the code env,
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% then you have no problem:
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% \def\ycube{$y^3$}
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% \begin{code} x := x+1 /* {\em This is \ycube} */ \end{code}
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% If you must put special chars inside the code env, you do it by
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% prefixing them with the special \dcd ("decode") command, that
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% reverts the chars to back to special status:
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% \begin{code} x := x+1 /* {\dcd\em This is $y^3$} */ \end{code}
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% \dcd's scope is bounded by its enclosing braces. It is only defined within
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% the code env. You can also turn on just $ with the \cddollar command;
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% you can turn on just $^_ with the \cdmath command. See below.
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%
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% Alternatively, just use \(...\) for $...$, \sp for ^, and \sb for _.
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% WARNING:
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% Like \verb, you cannot put a \cd{...} inside an argument to a macro
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% or a command. If you try, for example,
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% \mbox{\cd{$x^y$}}
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% you will lose. That is because the text "\cd{$x^y$}" gets read in
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% as \mbox's argument before the \cd executes. But the \cd has to
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% have a chance to run before LaTeX ever reads the $x^y$ so it can
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% turn off the specialness of $ and ^. So, \cd has to appear at
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% top level, not inside an argument. Similarly, you can't have
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% a \cd or a \code inside a macro (Although you could use \gdef to
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% define a macro *inside* a \cd, which you could then use outside.
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% Don't worry about this if you don't understand it.)
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% BUG: In the codebox env, the effect of a \dcd, \cddollar, or \cdmath
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% command is reset at the end of each line. This can be hacked by
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% messing with the \halign's preamble, if you feel up to it.
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% Useage note: the initial newline after the \begin{code} or
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% \begin{codebox} is eaten, but the last newline is not.
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% So,
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% \begin{code}
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% foo
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% bar
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% \end{code}
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% leaves one more blank line after bar than does
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% \begin{code}
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% foo
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% bar\end{code}
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% Moral: get in the habit of terminating code envs without a newline
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% (as in the second example).
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%
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% All this stuff tweaks the meaning of space, tab, and newline.
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%===============================================================================
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% \cd@obeyspaces
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% Turns all spaces into non-breakable spaces.
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% Note: this is like \@vobeyspaces except without spurious space in defn.
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% @xobeysp is basically a space; it's defined in latex.tex.
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%
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{\catcode`\ =\active\gdef\cd@obeyspaces{\catcode`\ =\active\let =\@xobeysp}}
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% \cd@obeytabs
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% Turns all tabs into 8 non-breakable spaces (which is bogus).
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%
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{\catcode`\^^I=\active %
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\gdef\cd@obeytabs{\catcode`\^^I=\active\let^^I=\cd@tab}}
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\def\cd@tab{\@xobeysp\@xobeysp\@xobeysp\@xobeysp\@xobeysp\@xobeysp\@xobeysp\@xobeysp}
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% \cd@obeylines
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% Turns all cr's into linebreaks. Pagebreaks are not permitted between lines.
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% This is copied from lplain.tex's \obeylines, with the cr def'n changed.
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%
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{\catcode`\^^M=\active % these lines must end with %
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\gdef\cd@obeylines{\catcode`\^^M=\active\let^^M=\cd@cr}}
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% What ^M turns into. This def'n keeps blank lines from being compressed out.
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\def\cd@cr{\par\penalty10000\leavevmode} % TeX magicness
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%\def\cd@cr{\par\penalty10000\mbox{}} % LaTeX
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% \codeallowbreaks
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% Same as \cd@obeylines, except pagebreaks are allowed.
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% Put this command inside a code env to allow pagebreaks.
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{\catcode`\^^M=\active % these lines must end with %
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\gdef\codeallowbreaks{\catcode`\^^M\active\let^^M\cd@crbr}}
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\def\cd@crbr{\leavevmode\endgraf} % What ^M turns into.
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% \cd@obeycrsp
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% Turns cr's into non-breakable spaces. Used by \cd.
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{\catcode`\^^M=\active % these lines must end with %
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\gdef\cd@obeycrsp{\catcode`\^^M=\active\let^^M=\@xobeysp}}
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% =============================================================================
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% Set up code environment, in which most of the common special characters
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% appearing in code are treated verbatim, namely: $&#^_~%
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% \ { } are still enabled so that macros can be called in this
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% environment. Use \\, \{, and \} to use these characters verbatim
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% in this environment.
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%
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% Inside a group, you can make
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% all the hacked chars special with the \dcd command
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% $ special with the \cddollar command
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% $^_ special with the \cdmath command.
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% If you have a bunch of math $..$'s in your code env, then a global \cddollar
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% or \cdmath at the beginning of the env can save a lot of trouble.
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% When chars are special (e.g., after a \dcd), you can still get #$%&_{} with
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% \#, \$, \%, \&, \_, \{, and \} -- this is standard LaTeX.
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% Additionally, \\ gives \ inside the code env, and when \cdmath
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% makes ^ special, it also defines \^ to give ^.
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%The hacked characters can be made special again
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% within a group by using the \dcd command.
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% Note: this environment allows no breaking of lines whatsoever; not
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% at spaces or hypens. To arrange for a break use the standard \- command,
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% or a \discretionary{}{}{} which breaks, but inserts nothing. This is useful,
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% for example for allowing hypenated identifiers to be broken, e.g.
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% \def\={\discretionary{}{}{}} %optional break
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% FOO-\=BAR.
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\def\setupcode{\parsep=0pt\parindent=0pt%
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\tt\frenchspacing\catcode``=13\@noligs%
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\def\\{\char`\\}%
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\let\dcd=\cd@dcd\let\cddollar=\cd@dollarspecial\let\cdmath=\cd@mathspecial%
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\@makeother\$\@makeother\&\@makeother\#%
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\@makeother\^\@makeother\_\@makeother\~%
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\@makeother\%\cd@obeytabs\cd@obeyspaces}
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% other: $&#^_~%
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% left special: \{}
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% unnecessary: @`'"
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%% codebox, centercode
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%%=============================================================================
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%% The codebox env makes a box exactly as wide as it needs to be
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%% (i.e., as wide as the longest line of code is). This is useful
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%% if you want to center a chunk of code, or flush it right, or
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%% something like that. The optional argument to the environment,
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%% [t], [c], or [b], specifies how to vertically align the codebox,
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%% just as with arrays or other boxes. Default is [c].
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%% Must be a newline immediately after "\begin{codebox}[t]"!
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{\catcode`\^^M=\active % these lines must end with %
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\gdef\cd@obeycr{\catcode`\^^M=\active\let^^M=\cr}}
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% If there is a [<letter>] option, then the following newline will
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% be read *after* ^M is bound to \cr, so we're cool. If there isn't
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% an option given (i.e., default to [c]), then the @\ifnextchar will
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% gobble up the newline as it gobbles whitespace. So we insert the
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% \cr explicitly. Isn't TeX fun?
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\def\codebox{\leavevmode\@ifnextchar[{\@codebox}{\@codebox[c]\cr}} %]
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\def\@codebox[#1]%
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{\hbox\bgroup$\if #1t\vtop \else \if#1b\vbox \else \vcenter \fi\fi\bgroup%
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\tabskip\z@\setupcode\cd@obeycr% just before cd@obey
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\halign\bgroup##\hfil\span}
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\def\endcodebox{\crcr\egroup\egroup\m@th$\egroup}
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% Center the box on the page:
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\newenvironment{centercode}%
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{\begin{center}\begin{codebox}[c]}%
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{\end{codebox}\end{center}}
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%% code, codeaux, tightcode
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%%=============================================================================
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%% Code environment as described above. Lines are kept on one page.
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%% This actually works by setting a huge penalty for breaking
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%% between lines of code. Code is indented same as other displayed paras.
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%% Note: to increase left margin, use \begin{codeaux}{\leftmargin=1in}.
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% To allow pagebreaks, say \codeallowbreaks immediately inside the env.
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% You can allow breaks at specific lines with a \pagebreak form.
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%% N.B.: The \global\@ignoretrue command must be performed just inside
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%% the *last* \end{...} before the following text. If not, you will
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%% get an extra space on the following line. Blech.
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%% This environment takes two arguments.
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%% The second, required argument is the \list parameters to override the
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%% \@listi... defaults.
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%% - Usefully set by clients: \topsep \leftmargin
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%% - Possible, but less useful: \partopsep
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%% The first, optional argument is the extra \parskip glue that you get around
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%% \list environments. It defaults to the value of \parskip.
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\def\codeaux{\@ifnextchar[{\@codeaux}{\@codeaux[\parskip]}} %]
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\def\@codeaux[#1]#2{%
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\bgroup\parskip#1%
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\begin{list}{}%
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{\parsep\z@\rightskip\z@\listparindent\z@\itemindent\z@#2}%
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\item[]\setupcode\cd@obeylines}%
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\def\endcodeaux{\end{list}\leavevmode\egroup\ignorespaces\global\@ignoretrue}
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%% Code env is codeaux with the default margin and spacing \list params:
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\def\code{\codeaux{}} \let\endcode=\endcodeaux
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%% Like code, but with no extra vertical space above and below.
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\def\tightcode{\codeaux[=0pt]{\topsep\z@}}%
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\let\endtightcode\endcodeaux
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% {\vspace{-1\parskip}\begin{codeaux}{\partopsep\z@\topsep\z@}}%
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% {\end{codeaux}\vspace{-1\parskip}}
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% Reasonable separation between lines of code
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\newcommand{\codeskip}{\penalty0\vspace{2ex}}
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% \cd is used to build a code environment in the middle of text.
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% Note: only difference from display code is that cr's are taken
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% as unbreakable spaces instead of linebreaks.
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\def\cd{\leavevmode\begingroup\ifmmode\let\startcode=\startmcode\else%
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\let\startcode\starttcode\fi%
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\setupcode\cd@obeycrsp\startcode}
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\def\starttcode#1{#1\endgroup}
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\def\startmcode#1{\hbox{#1}\endgroup}
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% Restore $&#^_~% to their normal catcodes
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% Define \^ to give the ^ char.
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% \dcd points to this guy inside a code env.
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\def\cd@dcd{\catcode`\$=3\catcode`\&=4\catcode`\#=6\catcode`\^=7%
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\catcode`\_=8\catcode`\~=13\catcode`\%=14\def\^{\char`\^}}
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% Selectively enable $, and $^_ as special.
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% \cd@mathspecial also defines \^ give the ^ char.
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% \cddollar and \cdmath point to these guys inside a code env.
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\def\cd@dollarspecial{\catcode`\$=3}
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\def\cd@mathspecial{\catcode`\$=3\catcode`\^=7\catcode`\_=8%
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\def\^{\char`\^}}
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% Change log:
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% Started off as some macros found in C. Rich's library.
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% Olin 1/90:
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% Removed \makeatletter, \makeatother's -- they shouldn't be there,
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% because style option files are read with makeatletter. The terminal
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% makeatother screwed things up for the following style options.
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% Olin 3/91:
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% Rewritten.
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% - Changed things so blank lines don't get compressed out (the \leavevmove
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% in \cd@cr and \cd@crwb).
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% - Changed names to somewhat less horrible choices.
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% - Added lots of doc, so casual hackers can more easily mess with all this.
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% - Removed `'"@ from the set of hacked chars, since they are already
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% non-special.
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% - Removed the bigcode env, which effect can be had with the \codeallowbreaks
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% command.
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% - Removed the \@noligs command, since it's already defined in latex.tex.
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% - Win big with the new \dcd, \cddollar, and \cdmath commands.
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% - Now, *only* the chars \{} are special inside the code env. If you need
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% more, use the \dcd command inside a group.
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% - \cd now works inside math mode. (But if you use it in a superscript,
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% it still comes out full size. You must explicitly put a \scriptsize\tt
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% inside the \cd: $x^{\cd{\scriptsize\tt...}}$. A \leavevmode was added
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% so that if you begin a paragraph with a \cd{...}, TeX realises you
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% are starting a paragraph.
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% - Added the codebox env. Tricky bit involving the first line hacked
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% with help from David Long.
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