\NeedsTeXFormat{LaTeX2e}[2.09]
\ProvidesPackage{ttquot}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% ttquot.sty
%
% This style is intended to make it easier to write text on technical
% subjects, so that the text is readable even when it is TeX source.
%
% One of the most common problems is switching conveniently into the
% typewriter font and back. This style file makes the ordinary double
% quotation mark (") serve this function. Note that the meaning of \tt
% may be different in math and text mode, for example if the "times"
% package is being used.
%
% This package also makes underscore characters (_) switch into
% emphasized mode and back, unless inside " quotes or in math mode. This
% makes ordinary variable names easier to type in typewriter font, and
% makes emphasized mode obey a common ASCII text convention.
%
% Options:
%   sfcode
%       Makes text inside quotation marks come out in \sf font.
%   small
%       Makes text inside quotation marks come out \small (except in math
%       mode.) This is especially useful when using the times package, because
%       the Courier and Helvetica fonts are larger than Times.
%   stdbraces
%       By default, the commands \{ and \} emit ordinary characters 123 and
%       125 inside quotation marks. This works well if you are in \tt font,
%       but not so well in a font (e.g., \sf) lacking these characters. Use
%       stdbraces to defeat it.
%   bfemph
%       Make underscore turn on boldface instead of italics.
%
% The following macros are defined and may be used or overridden.
%
% \ttquot@activate       Turn on ttquot processing. On by default.
% \ttquot@deactivate     Turn off ttquot processing.
% \ttquot@ttmode         The 'code' environment introduced by "
% \ttquot@emmode         The 'emphasized' environment introduced by _
% \ttquot@setup          Commands that are emitted in the " environment.
% \ttquot@ttfont         The font part of tt@setup, By default, \tt.
% \ttquot@ttsize         The font size part of tt@setup, By default, nothing.
% \ttquot@emfont         The commands that are emitted in the _ environment.
%                        By default, \em
% \ttquot@braces         Another command emitted in the " environment.
%                        By default, changes braces to use tt font chars.
%                        The "stdbraces" option defeats this.
% \ttquot@mark           Always represents the plain character (")
% \ttquot@us             Represents the original meaning of (_)
%
% This style file is maintained by Andrew Myers (andru@cs.cornell.edu)
%
% Change log:
%  Fri Nov  6 14:35:49 EST 1992         Added this documentation        andru
%  Tue Nov 10 23:05:44 EST 1992         Changed underscore to do \em    andru
%  Wed Nov 11 17:00:00 EST 1992         Fixed various bugs, added *     andru
%  Tue Feb 16 23:48:20 EST 1993         Fixed "number" bug, added \*    andru
%  Tue Mar 23 13:39:39 EST 1993         Got rid of a little cruft       andru
%  Tue Apr 26 16:07:18 EDT 1994         Made _ work in other fonts      andru
%  Wed Oct 12 17:39:49 EDT 1994         Made activate/deactivate work   andru
%  Wed Feb 08 15:00:31 EST 1995         Made * work again               andru
%  Wed Jun  7 18:08:23 EDT 1995         Got rid of *                    andru
%  Sun Aug  4 15:58:16 EDT 2002         Rewrite using environments      andru
%  Thu Aug 15 11:39:12 EDT 2002         More documentation              andru
% 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Options
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\DeclareOption{sfcode}{\def\ttquot@ttfont{\sf}}
\DeclareOption{small}{\def\ttquot@ttsize{\ifmmode\else\small\fi}}
\DeclareOption{stdbraces}{\def\ttquot@braces{}}
\DeclareOption{bfemph}{\def\ttquot@emfont{\bf}}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Save original definitions
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\let\ttquot@mark="% Catch original definition of quotation mark
\let\ttquot@us=_% Catch original definition of underscore

% Change character codes to make them active temporarily.
\catcode`\"=\active%
\catcode`\_=\active%

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Change " to place its contents inside {\ttquot@ttfont ... }
% Also, underscores are underscores, not subscripts
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\newenvironment{ttquot@ttmode}{%
\ttquot@setup%
\def_{\ifmmode\ttquot@us\else\_\fi}%
\def"{\end{ttquot@ttmode}}%
}%
{}

\def\ttquot@setup{
\ttquot@ttfont%
\ttquot@ttsize%
\ttquot@braces%
}

\def\ttquot@ttfont{\tt}
\def\ttquot@braces{\def\{{\char123}\def\}{\char125}}
\def\ttquot@ttsize{}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Change _ to place its contents inside {\ttquot@emfont ... }
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\newenvironment{ttquot@emmode}{%
\ttquot@emfont%
\def_{\end{ttquot@emmode}}%
}%
{}

\gdef\ttquot@emfont{\em}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Change LaTeX's verbatim mode to use \ttquot@ttfont
% instead of \tt; also, do right thing with _
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\def\@verbatim{\trivlist \item[]\if@minipage\else\vskip\parskip\fi
\leftskip\@totalleftmargin\rightskip\z@
\parindent\z@\parfillskip\@flushglue\parskip\z@
\@tempswafalse \def\par{\if@tempswa\hbox{}\fi\@tempswatrue\@@par}
\obeylines \ttquot@ttfont
\@noligs \let\do\@makeother \dospecials
\catcode`\_=13%
\def_{\_}
\catcode``=13%
}


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Macros to turn the package on and off
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\gdef\ttquot@activate{%
\catcode`\"=\active%
\catcode`\_=\active%
\def"{\begin{ttquot@ttmode}}
\def_{\ifmmode\ttquot@us\else\begin{ttquot@emmode}\fi}
}

\gdef\ttquot@deactivate{%
\def"{\ttquot@mark}%
\def_{\ttquot@us}%
\catcode`\"=12%
\catcode`\_=8%
}

% Restore character codes to avoid messing up other packages.
% Character codes will be turned back on at beginning of document.
\catcode`\"=12
\catcode`\_=8

\ProcessOptions
\AtBeginDocument{\ttquot@activate}