%
%  U L E M . S T Y
%
%  A style file to provide various types of underlining that can stretch 
%  between words and be broken across lines.  Use with LaTeX or plain TeX.
%  In LaTeX this style replaces italics with underlining in \em-phasized text.
%  It is most suitable for simple text such as {\em ibid.} or {\em \LaTeX:
%  A Document Preparation System\/} that may need to be underlined in a
%  manuscript submitted for publication.  This is ONLY to be used when emphasis
%  is delimited by braces.  A declaration \normalem (or the \usepackage
%  option "normalem") restores the normal \em behavior.
%
%  Full instructions appear after \endinput.  In summary:
%    \uline{important}   underlined text
%    \uuline{urgent}     double-underlined text
%    \uwave{boat}        wavy underline
%    \sout{wrong}        line drawn through word
%    \xout{removed}      marked over with //////.
%    {\em phasized\/}  | In LaTeX, by default, these are underlined; use
%    \emph{asized}     | \normalem or [normalem] to restore italics
%    \useunder{\uwave}{\bfseries}{\textbf}  
%                        use wavy underline in place of bold face
%
%  Copyright (c) 1989,1992,1993,1994 by Donald Arseneau
%
%  These definitions may be freely transmitted, reproduced, or modified for
%  non-commercial purposes provided that this notice is left intact.

%  Defend against multiple loading.
\expandafter \ifx \csname UL@box\endcsname \relax \else \endinput \fi

%  Set catcode of @ in case it isn't a "letter" already
\expandafter\edef\csname UL@catcode\endcsname
  {\catcode\string`\string @=\the\catcode\string`\@
  \let \csname UL@catcode\endcsname \noexpand\undefined}
\catcode\string`\@=11

\def\uline{\bgroup \ULset}

\newbox\UL@hyphenbox
\newbox\UL@box
\def\ULthickness{.4pt}% can change this with \renewcommand
\newskip\UL@skip
\newdimen\ULdepth  \ULdepth=\maxdimen
%  "maxdimen" depth causes the depth to be set according to the font.  You 
%  can change \ULdepth for a permanent setting or a special effect (\sout).

\let\LA@space\ \let\LA@hskip\hskip

\def\UL@end *{\relax\relax}% something harmless unlikely to be found elsewhere

%   For regular underlines, set the depth based on the font, or retain
%   preset value.
%
\def\ULset{\ifdim\ULdepth=\maxdimen\setbox\UL@box\hbox{(}\ULdepth\dp\UL@box\fi
  \def\UL@leadtype{\leaders \hrule \@height\dimen@ \@depth\ULdepth}%
  \dimen@-\ULdepth \advance\dimen@\ULthickness \ULon}

\def\ULon#1{\leavevmode\UL@ender \let\ULon\UL@onin \let\\\UL@cr 
  \everymath{\UL@hrest}\let\-\UL@dischyp \let\ \UL@space \let\hskip\UL@hskip 
  \let\newline\UL@newline % \let\@lnbk\UL@lnbk \let\@nolnbk\UL@nolnbk
  \def\hfil{\hskip\z@ plus1fil\relax}\def\hfill{\hskip\z@ plus1fill\relax}%
  \def\hss{\hskip\z@ plus1filminus1fil\relax}\let\penalty\UL@penalty
  \setbox\UL@hyphenbox\hbox{\setbox\UL@box\hbox{\char
    \ifnum \hyphenchar\font<\z@ \string`\-\else \hyphenchar\font\fi
    }\UL@putbox}\UL@word\@empty#1\xdef\UL@spfactor{\the\spacefactor} \UL@end * }

\def\UL@onin#1{\leavevmode\UL@ender % when nested, do multiple underlining 
  \dimen@\ULthickness \advance\ULdepth 3\dimen@ \advance\dimen@-\ULdepth 
  \setbox\UL@box\hbox{{#1}}\let\UL@start\relax\UL@putbox\egroup}
% \UL@putbox is disabled in inner mode, so re-enable it by changing \UL@start
% \UL@hrest is implicit due to \everyhbox

\def\UL@unegroup{}
\gdef\UL@ender{}
% end-brace matching hack for when command is used as a font declaration:
\def\UL@swender{\aftergroup\egroup\gdef\UL@ender{}}

% must expand to nothing outside the ifs for syntactical spaces to work
\def\UL@word#1 {\expandafter\UL@start#1 %
  \expandafter\ifx\expandafter\UL@end#1\egroup 
   \unskip \unskip \unskip % remove extra leader at end
   \spacefactor\UL@spfactor \let\UL@word\egroup
  \else % not finished
   \ifmmode\else \ifdim\lastskip=\z@\else % allow syntactical spaces
     \global\UL@skip\lastskip \unskip 
     \UL@stop \UL@leaders
   \fi\fi
  \fi \UL@word\@empty}% \@empty preserves braces in param 

\def\UL@start{\setbox\UL@box\hbox\bgroup
  \everyvbox{\UL@hrest}\everyhbox{\UL@hrest}%
% the following are to cope with stops (\ ,\- etc) within extra braces
  \let\UL@start\@empty \let\UL@unegroup\bgroup \let\UL@leadtype\@empty
  \kern-3sp\kern3sp % kerns so I can test for beginning of list
  \if@ignore \global\@ignorefalse \expandafter\ignorespaces \fi}

\def\UL@stop{\global\@clb\lastpenalty % store penalty in \@clb; no \cline here!
  \ifdim\lastkern=3sp \egroup % Nothing in hbox (?)
     \ifdim\wd\UL@box=\z@ \else \UL@putbox \fi % not true, so output box
  \else  \egroup \UL@putbox % something in box
  \fi \UL@unegroup}

\def\UL@putbox{\ifx\UL@start\@empty \else % not inner
   {\UL@skip\wd\UL@box \advance\UL@skip\UL@pixel
   \vrule \@height\dimen@ \@depth\ULdepth \@width\UL@skip
   \kern-\UL@skip}\box\UL@box
   \ifnum\@clb=\z@ \else \LA@penalty\@clb \fi
 \fi}

%  With interword leaders, give some overlap to avoid gaps caused by
%  round-off errors in the printing program.  Needs \unskip \unskip \unskip
%  above.  This version overlaps 1/300 inch, which looks good at high 
%  resolution, and will still work down to ~150 dpi.  Change the value
%  of \UL@pixel if necessary.

\newdimen\UL@pixel \UL@pixel=1truein \divide\UL@pixel 300

\def\UL@leaders{{\LA@hskip-\UL@pixel \advance\UL@skip\tw@\UL@pixel
   \UL@leadtype\LA@hskip\UL@skip  \LA@hskip-\UL@pixel}}

% restore some things for inside math or \mbox
\def\UL@hrest{\let\ \LA@space \let\-\@empty \let\penalty\LA@penalty}

\def\UL@space{\LA@space \global\UL@skip\lastskip \unskip \UL@reskip}% \

\def\UL@dischyp{\LA@penalty\z@ % zero penalty => no break (see \UL@stop)
  \UL@stop \discretionary{\copy\UL@hyphenbox}{}{}\UL@start}% \-

\let\LA@penalty\penalty
\def\UL@penalty{\ifhmode \afterassignment\UL@@penalty\count@
  \else\LA@penalty\fi}
\def\UL@@penalty{\LA@penalty \ifnum\count@=\z@ 
  \@ne \else \count@ \fi % zero penalty => no penalty, so use 1 instead.
  \UL@stop \UL@start}

% The test  \ifx\ \LA@space \else  means we are neither in math mode nor an
% \mbox, so it is safe to stop the current \UL@box.  \ , \- , and \penalty 
% (= \linebreak or \nolinebreak) are common enough that they are restored 
% directly (by \UL@hrest); \\, \newline, \hskip (= \hspace) are rare enough 
% that the test is incorporated in their UL versions. This adds processing 
% when they're used, but saves processing in \UL@hrest called by \everymath 
% and \everyhbox.

\def\UL@hskip{\ifx\ \LA@space \LA@hskip \else
  \afterassignment\UL@reskip \global\UL@skip \fi}

\def\UL@reskip{\UL@stop \UL@leaders \UL@start}

% Redefine \\ and \newline so the vertical space from \\[ ] is not lost
% and so the \hfil is not underlined!  \\ and \newline do nothing if inside 
% inner braces.
 
\def\UL@cr{\unskip \ifx\ \LA@space \else \UL@stop \fi
  \unskip\unskip\unskip \@normalcr}

\def\UL@newline{\ifx\UL@start\@empty % (\UL@cr may have \UL@stop-ed already)
  \unskip \ifx\ \LA@space \else \UL@stop \fi \fi
  \unskip\unskip\unskip \LA@hskip \z@ plus1fil\LA@penalty -\@M \UL@start}

% That concludes the basic underlining.  To put various other objects
% (characters) under (or over) text we need to use some slightly different
% macros, identified by the ULC@ in the name...

\newbox\ULC@box

\def\ULC@putbox{\ifx\UL@start\@empty \else % not inner
  \vrule\@width\z@ \LA@penalty\@M
  {\UL@skip\wd\UL@box \UL@leaders}\kern-\wd\UL@box \box\UL@box
  \ifnum\@clb=\z@ \else \LA@penalty\@clb \fi \fi}

% ... and \markoverwith sets up each type of special underline by
% switcing to the \ULC@ commands.

\def\markoverwith#1{\def\UL@leadtype{\leaders\copy\ULC@box}% box size -> pixel size
   \let\UL@putbox\ULC@putbox \setbox\ULC@box\hbox{#1}\UL@pixel.5\wd\ULC@box}

% Now define various special underlines.  All the definitions go like
% \def \command {\bgroup \markoverwith{something} \ULon}

% For drawing a wavey underline instead of a straight one the command
% is \uwave (under-wave) which uses the wiggle from 6-pt lasy font:

\def\uwave{\bgroup \markoverwith{\lower3.5pt\hbox{\sixly
  \kern-.21pt \char58 \kern-.21pt }}\ULon}
\font\sixly=lasy6 % does not re-load if already loaded, so no memory problem.

% To draw a double underline under text, use \uuline{text}

\def\uuline{\bgroup \markoverwith{\hbox
 {\kern-.03em\vtop{\kern.2ex\hrule width.2em\kern1.1pt\hrule}\kern-.03em}%
 }\ULon}

% To draw a line through text instead of under it (strike out)
% do `under' line with negative depth.  Note that this one uses a
% real line, not characters, so there is no \markoverwith.

\def\sout{\bgroup \ULdepth=-.5ex \ULset}

% To mark //// over text instead of underlining (x-out)
%
\def\xout{\bgroup \markoverwith{\kern-.1em/\kern-.1em}\ULon}

% \useunder {underline_command}{font_declaration}{font_command}
% e.g.: \useunder{\uuline}{\bfseries}{\textbf}
%       \useunder{\uwave}{\bf}{}
\def\useunder#1#2#3{\relax
  \ifx\relax#2\relax\else % declaration command given
    \def#2{\def\@tempa{#1}\global\let\UL@ender\UL@swender
    \expandafter\@tempa\expandafter{\ifnum\z@=\string`}\fi}%
    \MakeRobust{#2}\fi
  \ifx\relax#3\relax\else \def#3{#1}\MakeRobust{#3}\fi % argumentative command
}

\ifx\@ifundefined\undefined

% Allow plain TeX to use this style:
  \def\@height{height}
  \def\@depth{depth}
  \def\@width{width}
  \def\@empty{}
  \def\@gobble#1{}
  \def\MakeRobust#1{}
% Do non-outer \newif with no visible \if's or \fi's when skipping
  \csname newif\expandafter\endcsname \csname if@ignore\endcsname
  \csname newcount\endcsname\@clb

\else

 \def\MakeRobust#1{\expandafter\let
   \csname \expandafter\@gobble\string#1 \endcsname=#1%
  \edef#1{\noexpand\protect \expandafter\noexpand
   \csname\expandafter\@gobble\string#1 \endcsname}
  }
  \MakeRobust\uline
  \MakeRobust\uuline
  \MakeRobust\uwave
  \MakeRobust\sout
  \MakeRobust\xout

  \let\LA@em\em   \let\LA@emph\emph
  \expandafter\let\expandafter\LA@Pem \csname em \endcsname
  \expandafter\let\expandafter\LA@Pemph \csname emph \endcsname
  \def\ULforem{\useunder{\uline}{\em}{\emph}}
  \def\normalem{\let\em\LA@em \let\emph\LA@emph
    \expandafter\let\csname em \endcsname\LA@Pem
    \expandafter\let\csname emph \endcsname\LA@Pemph}
  \ULforem  %  default is to use underlining for \em,

\fi

% Process LaTeX \package options; plain TeX skips this section

\ifx\ProvidesPackage\undefined \else
  \ProvidesPackage{ulem}[1994/07/23]
  \DeclareOption{normalem}{\normalem}
  \DeclareOption{ULforem}{\ULforem}
  \DeclareOption{normalbf}{}
  \DeclareOption{UWforbf}{\useunder{\uwave}{\bfseries}{\textbf}}
  \ProcessOptions 
\fi

\UL@catcode % restore catcode of @ to starting value

\endinput

ULEM is a package for LaTeX or plain TeX which provides various types of
underlining that can stretch between words and be broken across lines. 
In LaTeX this style replaces italics with underlining in emphasized text
given by \em or \emph -- but only if the text is delimited by braces.  A
declaration \normalem (or the \usepackage option [normalem]) restores the
normal \em behavior.  For underlining in plain TeX, \input ulem.sty, and 
use the \uline command.

Unlike regular underlining, ulem allows line breaks, and even primitive
hyphenation, within the underlined text; but it is far from perfect. It is
most suitable for simple text like  {\em \LaTeX: A document preparation
system\/} that may need to be underlined in a manuscript submitted for
publication.  Again, ulem will only replace \em and \emph when the text is
delimited by explicit braces.  The thickness of the underline rule is given
by \ULthickness; use \renewcommand or \def (not \setlength) to change it.
The depth of the underline is controlled by the length \ULdepth. The default 
value is a special flag which lets the current font control the depth. 
You can set a particular value to \ULdepth (using \setlength) to force a 
particular depth, either locally for a special purpose, or for the document
as a whole.  See the definition of \sout.

Every word is typeset in an underlined box, so automatic hyphenation is
normally disabled, but explicit discretionary hyphens (\-) will still be
obeyed.  Several text-formatting commands are specially supported within 
the underlining:  \-, \ , ~, \\, \newline, \linebreak, \nolinebreak, 
\penalty, \hskip, \hspace, \hfil, \hfill, \hss.  Displayed math and \par 
are deliberately not supported to aid in the detection of runaway arguments 
(missing braces).  The special commands do have a problem: they end a
group so any local assignments are lost.

The underlines continue between words, and stretch just like ordinary
spaces do.  Since spaces delimit words, there may be some difficulty with
syntactical spaces (e.g. "2.3 pt"). Some effort is made to handle such
cases, but sometimes [such as \let\x= y] the space is interpreted
incorrectly. You can usually solve the problem by enclosing the offending
command in braces or in a macro [\newcommand\xeqy{\let\x= y}], but...

One important incompatability with braces and macro replacement:  
ALL THE TEXT IN BRACES OR COMING FROM A MACRO IS TYPESET IN A BOX.  
That is, braces will suppress stretching and linebreaks in the text they
enclose.  Moreover, the specially-taken-care-of commands \-, \\, \newline
and \linebreak are usually ignored if they appear inside extra braces.
They operate only when the braces delimit a command parameter without
introducing a level of grouping.  (Even though braces delimiting command 
parameters do not normally imply grouping, many commands will add their
own grouping.)  Thus, you should try to limit inner braces to short bits of
text or for delimiting parameters to commands. For emergengy repairs, see
the "Marat/Sade" example below.  Syntactical spaces inside braces never
cause a problem, nor do spaces in math mode. 

Text produced by expansion of a command (macro) is boxed too, but \\, \
and \- still work properly in the expansion text:
        \newcommand\iff{if and only if} {\em \iff}
does not allow any stretching or linebreaking between words, but
        \newcommand\iff{if\ and\ only\ if} {\em \iff}
allows stretching and linebreaking.  There is a problem though:  the 
\  between words closes a group and any local assignments will be lost, 
in particular, font changes. 

Nested \em commands produce multiple underlining, but heed the warnings
about braces above.  To get italics without underlining, use \it.  Nesting
of other types of underline is also possible, but the `underlines' may
overlap. 

HERE IS A SIMPLE EXAMPLE.

\noindent 'Twas {\em brillig\/} and the {\em slithy~toves\/}
did {\em gyre\/} and {\em gim\-ble\/} in the {\em wabe,\\[2pt] }
All {\em mim\-sey\/} were the {\em boro\-goves\/} and
the {\em mome raths outgrabe}.

HERE IS A DIFFICULT EXAMPLE.

\usepackage{ulem}
\setlength\textwidth{3.3in}
\begin{document}
% \large
No, I did {\em not} act in the movie {\em \emph{The} %    <<<<<<< Nested
\emph{Persecu}\-\emph{tion} \emph{and} \emph{Assassination} \emph{of}
\emph{Jean-Paul} \emph{Marat}, as per\-formed by the Inmates
of the Asylum of Charenton under the Direc\-tion of the
Marquis de~Sade!} But I {\em did} see it.
\end{document}

In the nested emphasis, \emph had to be given for each word separately 
so the spaces between could stretch and break into lines.  Even the
discretionary hyphen (\-) in `Persecution' had to be outside the braces,
but the hyphen in Direction was just fine because it was not in nested
braces. The same applies to other special commands like \  and ~. This
example really illustrates that ULEM does not handle nested emphasis very
well!  Nevertheless, it is fine for simple things. 

Underlining can also be done according to \uline{this text}. To use this
type of underlining, but have \em still produce italics, put the command
\normalem in the preamble of the document or load ulem with
\usepackage[normalem]{ulem}. 

Some variations on underlining are provided, including a wavey underline 
(\uwave{under-wave}), double underlines (\uuline{two lines under this}), 
a line through text rather than under it (\sout{strike out}), text
crossed-out with /////// (\xout{cross out, X out}).  You can define your
own styles following the examples provided.  The definition should be 
something like: 

\newcommand\command{\bgroup \markoverwith{something}\ULon}

Any type of underlining can be substituted for any font-selection command 
by issuing a proper \useunder declaration:

\useunder{\underlinecommand}{\fontdeclaration}{\fontcommand}

e.g., \useunder{\uuline}{\bfseries}{\textbf} gives a double underline
instead of bold face in LaTeX.  The commands \normalem and \ULforem
switch underlining for \em off and on, respectively, and so do the
\usepackage options [normalem] and [ULforem]. There is also the
\usepackage style option [UWforbf] to replace boldface with a wavey
underline: \useunder{\UWave}{\bfseries}{\textbf}. This doesn't work
in section titles, unfortunately, because the titles are not simple
text and are not delimited by explicit braces.  In plain TeX you get
this with the command \useunder{\UWave}{\bf}{}. You can even skip a
step: \useunder{\bgroup\markoverwith{!}\ULon}{\sf}{}! 

All the underlining commands are robust in LaTeX.

%  Previous bug-finders: Esther Hu (\hfill in plain); Lones Smith (\tt\-);
%  Steve Anderson (\ooalign accents).
%  The bug finders' fee is now $0.00; it will double for each new bug found.
%  Version 1994:
%  Many changes! Notably: LaTeX2e options and \emph. Nesting works (somewhat). 
%  Behavior with inner braces is more consistent (not stripped).  \useunder.  
%  Better underwave (using lasy6). Special underlines are not commented out.
%
%  Send problem reports to asnd@reg.triumf.ca
%
% test integrity:
% brackets:  round, square, curly, angle:   () [] {} <>
% backslash, slash, vertical, at, dollar, and: \ / | @ $ &
% hat, grave, acute (apostrophe), quote, tilde, under:   ^ ` ' " ~ _
