%
%  U L E M . S T Y       [2012-05-18]
%
%  The ulem package provides various types of underlining that can stretch
%  between words and be broken across lines in LaTeX or plain TeX.
%  In LaTeX ulem replaces italics with underlining in \em-phasized text.
%  It is most suitable for simple text such as {\em ibid.} or \emph{\LaTeX:
%  A Document Preparation System} that may need to be underlined in a
%  manuscript submitted for publication.  A declaration of \normalem (or 
%  the \usepackage option "normalem") restores the normal \em behavior.
%
%  Full instructions appear in ulem.ltx (ulem.pdf).  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 //////.
%    \dashuline{dashing} dash underline
%    \dotuline{dotty}    dotted underline
%
%    {\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
%    Use \markoverwith for defining new types of underlining.
%
%  Copyright (c) 1989-2011 by Donald Arseneau (Vancouver, Canada; asnd@triumf.ca)
%
%  This software may be freely transmitted, reproduced, or modified for any
%  purpose provided that this copyright notice is left intact.  
%  (Small excerpts may be taken and used without any restriction.)
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%  Defend against multiple loading.
\expandafter \ifx \csname UL@box\endcsname \relax \else 
 \immediate\write16{ulem.sty refuses to load twice. }\endinput \fi

%  Set catcode of @ in case it isn't a "letter" already
\chardef\ULthickness\catcode\string`\@ % hold catcode temporarily
\catcode\string`\@=11

\def\uline{\relax \ifmmode\expandafter\underline 
           \else \bgroup\expandafter\ULset\fi}

\newbox\UL@box
\newbox\UL@hyphenbox
\newskip\UL@skip
\newtoks\UL@hook

\newdimen\UL@height

\newcount\UL@pe
\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
%   the preset value, then start underlining.
\def\ULset{\UL@setULdepth
  \def\UL@leadtype{\leaders \hrule \@height\UL@height \@depth\ULdepth}%
  \ifmmode \ULdepth-4\p@ \fi
  \UL@height-\ULdepth \advance\UL@height\ULthickness \ULon}

% Automatically set \ULdepth if it is to be automatic (flagged by \maxdimen)
\def\UL@setULdepth{\relax
  \ifdim\ULdepth=\maxdimen  % Set depth based on font, if not set already
   \setbox\UL@box\hbox{{(j}}\ULdepth\dp\UL@box\advance\ULdepth.4\p@
   % use setbox to support plain TeX
 \fi}

%   \ULon simply calls \UL@on (possibly \UL@on=\UL@onin) for text mode, but
%   \UL@onmath if it is math mode.
\def\ULon{\ifmmode \expandafter\UL@onmath\else \expandafter\UL@on\fi}

%   \UL@on sets the engine of underline running, and tells it
%   where to stop.
\long\def\UL@on#1{\leavevmode\UL@ender \let\UL@on\UL@onin 
  \everymath{\UL@hrest}\everyvbox{\UL@hrest}\let\hskip\UL@hskip
  \let\\\UL@cr \let\-\UL@dischyp \let\newline\UL@newline \let\ \UL@space
  \def\hfil{\hskip\z@ plus1fil\relax}\def\hfill{\hskip\z@ plus1fill\relax}%
  \def\hss{\hskip\z@ plus1filminus1fil\relax}\let\penalty\UL@penalty
  \the\UL@hook
  \UL@word\@empty#1\xdef\UL@spfactor{\the\spacefactor} \UL@end * }

%   This is what \ULon does when it appears nested in an inner place.
\def\UL@onin#1{\leavevmode\UL@ender % when nested, do multiple underlining
  \UL@height\ULthickness \advance\ULdepth\thr@@\UL@height 
  \advance\UL@height-\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.  Double braces for \hbox are in
% lieu of \color@begin(end)group.

%   This is what \ULon does in math mode.
\def\UL@onmath#1{\UL@ender\mathord{\UL@hrest\mathop{\kern\z@#1}\limits\sb
  {\UL@leadtype\LA@hskip\p@ plus1fill}}\egroup}

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

% must expand to nothing outside the ifs for syntactical spaces to work.
% the \expandafters get rid of the \@empty inserted at the beg. of word
\def\UL@word#1 {\expandafter\UL@start#1 %
  \expandafter\ifx\expandafter\UL@end#1\egroup\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

% \UL@start: start of each chunk. It gives two levels of grouping.
% Each chunk is ended by \UL@stop.  Local intermissions go like
% \UL@stop...\UL@start.
\def\UL@start{\setbox\UL@box\hbox\bgroup\everyhbox{\UL@hrest}%
% the following are to cope with stops (\ ,\- etc) within extra braces
  \let\UL@start\@empty \def\UL@unegroup{\bgroup\bgroup}\let\UL@leadtype\@empty
  \bgroup \kern-3sp\kern3sp % kerns so I can test for beginning of list
  \if@ignore \global\@ignorefalse \ignorespaces \fi}

\def\UL@stop{\global\UL@pe\lastpenalty \unpenalty % penalty in \UL@pe
  \ifnum\lastkern=\thr@@ \egroup\egroup % Nothing in hbox...but make sure:
    \ifdim\wd\UL@box=\z@ \else \UL@putbox \fi % something in box so print it
  \else  \egroup\egroup \UL@putbox % something in box so print it
  \fi \ifnum\UL@pe=\z@ \else \LA@penalty\UL@pe \fi % use penalty from inside box
  \UL@unegroup}
% notice that a box with only a penalty in it is discarded, but the penalty
% is still used!  This is so a series of discardable glues and penalties
% behaves properly.

\def\UL@putbox{\ifx\UL@start\@empty \else % not inner
  \vrule\@width\z@ \LA@penalty\@M
  {\UL@skip\wd\UL@box \UL@leaders \kern-\UL@skip}%
  \box\UL@box  \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=1in \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}% \

% Hyphenation is done by explicit \discretionary.  The overlapping melds
% with the running overlap because it *is* part of the running overlap:
% The word fragment is extended by the width of the hyphenation which is
% then overlapped by leaders.  The discretionary may occupy this space
% if a break occurs; otherwise the next syllable gets doubly-overlapped
% (in registration) for a distance of the hyphen's width.
\def\UL@dischyp{\global\setbox\UL@hyphenbox\hbox
   {\ifnum \hyphenchar\font<\z@ \string-\else \char\hyphenchar\font \fi}%
   \kern\wd\UL@hyphenbox \LA@penalty\@M 
   \UL@stop \kern-\wd\UL@hyphenbox
   \discretionary{\box\UL@hyphenbox}{}{}\UL@start}

\let\LA@penalty\penalty
\def\UL@penalty{\relax\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
% \everyvbox 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 \let\UL@vad\@gobble
  \else \UL@stop \unskip\unskip\unskip \let\UL@vad\vadjust \fi
  \@ifstar{\UL@vad{\LA@penalty\@M}\UL@cra}\UL@cra}
\def\UL@cra{\@ifnextchar[\UL@crb\UL@newline}
\def\UL@crb[#1]{\UL@vad{\vskip#1}\UL@newline}

\def\UL@newline{\ifx\UL@start\@empty % (\UL@cr may have \UL@stop-ed already)
  \unskip \ifx\ \LA@space \else \UL@stop \unskip\unskip\unskip \fi\fi 
  \LA@hskip \z@\@plus.0001fil\LA@penalty -\@M \UL@start}

% That concludes the basic underlining.  To put various other objects
% (characters) under (or over) text we need to define \markoverwith
% to set the overlay material in a box, and use leaders of that box for
% overlaying the text.  Here, the meaning of \UL@pixel is changed so
% that  `pixel' size = box size.  Note that we generally need \leaders
% (not \cleaders) for text, because an underline will be a patchwork 
% of small \leaders, and the characters must stay in registration.
% However, we "hook" the leaders command so specific applications can
% reassign it (\let\ULleaders\xleaders or \let\ULleaders\cleaders).
%
\newbox\ULC@box
\let\ULleaders\leaders

\def\markoverwith#1{\setbox\ULC@box\hbox{{#1}}\UL@pixel.5\wd\ULC@box
   \ifmmode \setbox\ULC@box\hbox{\raise1.4ex\box\ULC@box}%
    \dp\ULC@box-1.4ex\ht\ULC@box\z@ \def\UL@leadtype{\cleaders\copy\ULC@box}%
   \else
    \def\UL@leadtype{\ULleaders\copy\ULC@box}%
   \fi}

% 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{\lower3.5\p@\hbox{\sixly \char58}}\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 \UL@setULdepth
 \markoverwith{\lower\ULdepth\hbox
   {\kern-.03em\vbox{\hrule width.2em\kern1.2\p@\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=-.55ex \ULset}

% To mark //// over text instead of underlining (x-out)
%
\def\xout{\bgroup \markoverwith{\hbox to.35em{\hss/\hss}}\ULon}

\def\dotuline{\bgroup 
  \UL@setULdepth
  \markoverwith{\begingroup
     \advance\ULdepth0.08ex 
     \lower\ULdepth\hbox{\kern.1em .\kern.04em}%
     \endgroup}%
  \ULon}

\def\dashuline{\bgroup 
  \UL@setULdepth
  \markoverwith{\kern.13em
  \vtop{\kern\ULdepth \hrule width .3em}%
  \kern.13em}\ULon}

% A command to declare that an underline command should be used in 
% place of a particular font selection:
% \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 % argumentative command
    \def#3{#1}\MakeRobust{#3}\fi}

\expandafter\ifx \csname @ifundefined\endcsname \relax

% Allow plain TeX to use ulem.sty:
  \def\@height{height}
  \def\@depth{depth}
  \def\@width{width}
  \def\@empty{}
  \long\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

\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

\expandafter\ifx\csname ProvidesPackage\endcsname \relax \else
  \ProvidesPackage{ulem}[2012/05/18]
  \DeclareOption{normalem}{\normalem}
  \DeclareOption{ULforem}{\ULforem}
  \DeclareOption{normalbf}{}
  \DeclareOption{UWforbf}{\useunder{\uwave}{\bf}{\textbf}}
  \ProcessOptions
%
  \AtBeginDocument{\let\UL@marginpar\marginpar}%
  \newcommand\UL@marpar[2][\gDefault@pt]{\gdef\gDefault@pt{#2}%
   \ifx\ \LA@space \@latexerr{Marginpar lost}%
   \else \UL@stop \UL@marginpar[#1]{#2}\UL@start \fi}
  \addto@hook\UL@hook{\let\marginpar\UL@marpar}
\fi

\catcode`@=\ULthickness % Scratch meaning: restore catcode of @ 

\def\ULthickness{.4pt}% can change this with \renewcommand
\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).

\endinput

%====================== BEGIN INSTRUCTIONS ===========================
These plain text instructions may disappear soon.  The primary instructions
are in ulem.ltx (ulem.pdf, ulem.dvi).

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 incompatibility 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 emergency 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 and color changes.

This loss of local assignments will break some other standard commands,
(e.g., \cite) which produce multiple `words' using local assignments.
The way to protect such commands is to bury them in an \mbox:
        {\em every\-one agrees~\mbox{\cite{you,me}}.}

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 ~. Also,
the spaces are printed with only a single underline because they are
outside the nested \emph commands.  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}),
dashed (\dashuline{dashes underneath}) or dotted (\dotuline{dots below})
underlines,
a line through text rather than under it (\sout{strike out}), and 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}

The "something" can be as simple as a single character, or as complex as
you can keep track of.

The various underlining commands are essentially textual, and will not
work quite the same in math mode.  But since some font commands, like \bf,
serve both for text and math, math mode is handled (in an approximate way).
The performance in math mode is somewhat different from in text: there will
be no line breaks or stretching in the underlined text, and the vertical
positioning may not be right.  The results should be best for \uline,
\uwave, \uuline, and any other truly UNDER-line you define.

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.

UWforbf does handle \bf in math mode, but it doesn't work in section titles,
unfortunately, because the titles are not delimited by explicit braces when
printed by the \section command.  For the present version, the \bfseries
command still produces bold face, but \bf makes an under-wave. To get under-
waved section titles you can do

\renewcommand\@seccntformat[1]{\uwave{\csname the#1\endcsname}\hskip 1em}

and later specify \section[...]{\uwave{...}}.

In plain TeX there is no \textbf so you should use \useunder{\UWave}{\bf}{}.
You can even skip a step and define the underline or overprint with \useunder:
\useunder{\bgroup\markoverwith{!}\ULon}{\sf}{}

Some commands, such as \\ and \hskip are given special treatment, but 
others (like \marginpar) are not.  Support for others can be added by 
assigning special meanings in the token register \UL@hook.  (In LaTeX do 
\addto@hook\UL@hook{\let\command\ULversion}.)  The UL versions of commands 
should be modelled on \UL@hskip or \UL@cr, and should include the test 
"\ifx\ \LA@space".  For example, support for "\marginpar" is added through
the hook mechanism.

All the underlining commands are robust in LaTeX.

%====================== END INSTRUCTIONS ===========================

%  Previous bug-finders: Esther Hu (\hfill in plain); Lones Smith (\tt\-);
%  Steve Anderson (\ooalign accents); Thanassi Protopapas ( { in tables).
%  The bug finders' fee is now $0.00; it will double for each new bug found.
%  Version (identified by year)
%  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.
%  patch 1995:  fix \UL@swender to work in {tabular}; make hyphenation join
%  well; crude math support; eliminate \@clb
%  1996: use "\csname ProvidesPackage\endcsname", tidying.
%  1997: fix \\ when LaTeX changed; remove extra overlap in putbox.
%  2000: hook (and marginpar)
%  2004: Fix spacing in \uwave and \xout. \ULleaders hook.
%  2009: Accept \par in argument (\long)
%  2010: Include \dotuline and \dashuline, typeset documentation, add \UL@setULdepth
%  2011: Change \dimen@ to \UL@height
%  2012: Removed \let\par garbage
%
%  Send problem reports to asnd@triumf.ca
%
% test integrity:
% brackets:  round, square, curly, angle:   () [] {} <>
% backslash, slash, vertical, at, dollar, and: \ / | @ $ &
% hat, grave, acute (apostrophe), quote, tilde, under:   ^ ` ' " ~ _