bytefield 2.0 (30jan11)

git-svn-id: svn://tug.org/texlive/trunk@21225 c570f23f-e606-0410-a88d-b1316a301751

8 files changed, 1713 insertions, 478 deletions

diff --git a/Master/texmf-dist/doc/latex/bytefield/README b/Master/texmf-dist/doc/latex/bytefield/README
index 66ba8b7a5bd..24710fe8d9b 100644
--- a/Master/texmf-dist/doc/latex/bytefield/README
+++ b/Master/texmf-dist/doc/latex/bytefield/README
@@ -34,7 +34,7 @@ hyperref hyperlinks.
 Copyright and license
 ---------------------
 
-Copyright (C) 2010 Scott Pakin, scott+bf@pakin.org
+Copyright (C) 2011 Scott Pakin, scott+bf@pakin.org
 
 This package may be distributed and/or modified under the conditions
 of the LaTeX Project Public License, either version 1.3a of this
diff --git a/Master/texmf-dist/doc/latex/bytefield/bf-example.pdf b/Master/texmf-dist/doc/latex/bytefield/bf-example.pdf
new file mode 100644
index 00000000000..44f931eea43
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/bytefield/bf-example.pdf
diff --git a/Master/texmf-dist/doc/latex/bytefield/example.tex b/Master/texmf-dist/doc/latex/bytefield/bf-example.tex
index 1c69023fdcd..1604261a2c1 100644
--- a/Master/texmf-dist/doc/latex/bytefield/example.tex
+++ b/Master/texmf-dist/doc/latex/bytefield/bf-example.tex
@@ -1,14 +1,14 @@
 \documentclass[11pt]{article}
-\usepackage{fullpage}
+\usepackage[margin=1in]{geometry}
 \usepackage{longtable}
-\usepackage{bytefield}
+\usepackage[bitheight=6ex]{bytefield}
 \usepackage{color}
 \usepackage[bookmarksopen=true]{hyperref}
 
 \title{Integrating \texttt{bytefield} and \texttt{hyperref}}
 \author{\href{http://www.pakin.org/~scott}{Scott Pakin 
   \texttt{<scott+bf@pakin.org>}}}
-\date{21 June 2000}
+\date{18 January 2011}
 \hypersetup{%
 pdftitle={Integrating bytefield and hyperref},
 pdfauthor={Scott Pakin <scott+bf@pakin.org>},
@@ -100,12 +100,11 @@ not require hyperlinks to be re-specified when the figure changes.
    they exist, must always have a value of zero.
 
 \begin{figure}[htbp]
-  \begin{center}
-  \setlength{\byteheight}{6ex}
+  \centering
   \begin{bytefield}{32}
     \bitheader{0,7-8,15-16,23-24,31} \\
 
-    \wordgroupr{transport \\ header}
+    \begin{rightwordgroup}{transport \\ header}
       % We have to do the \parbox explicitly in the next line because
       % \hyperlink typesets its argument in horizontal mode.
       \bitbox{8}{\hyperlink{protocol-version}{\parbox{\width}{\centering protocol version}}} &
@@ -123,16 +122,15 @@ not require hyperlinks to be re-specified when the figure changes.
 
       \bitbox{16}{\hyperlink{window}{window}} &
       \bitbox{16}{\hyperlink{retention}{retention}}
-    \endwordgroupr \\
+    \end{rightwordgroup} \\
 
-  \wordgroupr{data \\ fields}
+  \begin{rightwordgroup}{data \\ fields}
     \wordbox[lrt]{1}{%
       \parbox{0.6\width}{\centering (data content and format dependent on packet type and modifier)}} \\
     \skippedwords \\
     \wordbox[lrb]{1}{} 
-  \endwordgroupr
+  \end{rightwordgroup}
   \end{bytefield}
-  \end{center}
   \caption{MTP packet format}
   \label{fig:packet-format}
 \end{figure}
@@ -351,8 +349,7 @@ not require hyperlinks to be re-specified when the figure changes.
    into the web.}
 
 \begin{figure}[htbp]
-  \begin{center}
-  \setlength{\byteheight}{6ex}
+  \centering
   \begin{bytefield}{32}
     \bitheader{0,7-8,15-16,23-24,31} \\
 
@@ -362,7 +359,6 @@ not require hyperlinks to be re-specified when the figure changes.
     \bitbox{16}{\hyperlink{msg-seq}{message sequence number}} &
     \bitbox{16}{\hyperlink{packet-seq}{packet sequence number}}
   \end{bytefield}
-  \end{center}
   \caption{Message acceptance record}
   \label{fig:msg-accept}
 \end{figure}
diff --git a/Master/texmf-dist/doc/latex/bytefield/bytefield.pdf b/Master/texmf-dist/doc/latex/bytefield/bytefield.pdf
index e2d1e3bbcf0..b00314cce3e 100644
--- a/Master/texmf-dist/doc/latex/bytefield/bytefield.pdf
+++ b/Master/texmf-dist/doc/latex/bytefield/bytefield.pdf
diff --git a/Master/texmf-dist/doc/latex/bytefield/example.pdf b/Master/texmf-dist/doc/latex/bytefield/example.pdf
deleted file mode 100644
index 57d9108c361..00000000000
--- a/Master/texmf-dist/doc/latex/bytefield/example.pdf
+++ /dev/null
diff --git a/Master/texmf-dist/source/latex/bytefield/bytefield.dtx b/Master/texmf-dist/source/latex/bytefield/bytefield.dtx
index 4f6d096cb78..7a6c8b42a81 100644
--- a/Master/texmf-dist/source/latex/bytefield/bytefield.dtx
+++ b/Master/texmf-dist/source/latex/bytefield/bytefield.dtx
@@ -1,6 +1,6 @@
 % \iffalse meta-comment
 %
-% Copyright (C) 2010 by Scott Pakin <scott+bf@pakin.org>
+% Copyright (C) 2011 by Scott Pakin <scott+bf@pakin.org>
 % ------------------------------------------------------
 %
 % This file may be distributed and/or modified under the
@@ -22,7 +22,7 @@
 %<package>\NeedsTeXFormat{LaTeX2e}[1999/12/01]
 %<package>\ProvidesPackage{bytefield}
 %<*package>
-    [2010/10/31 v1.3 Network protocol diagrams]
+    [2011/01/25 v2.0 Network protocol diagrams]
 %</package>
 %
 %<*driver>
@@ -31,27 +31,29 @@
 \usepackage{bytefield}
 \usepackage{color}
 \usepackage{rotating}
+\usepackage{multirow}
 \usepackage{calc}
 \usepackage{array}
-\IfFileExists{hyperref.sty}{%
-  \usepackage{hyperref}
-  \definecolor{darkred}{rgb}{0.5,0,0}
-  \definecolor{darkgreen}{rgb}{0,0.3,0}
-  \definecolor{darkblue}{rgb}{0,0,0.5}
-  \definecolor{darkbrown}{rgb}{0.28,0.07,0.07}
-  \hypersetup{%
-    pdftitle={The bytefield package},
-    pdfauthor={Scott Pakin <scott+bf@pakin.org>},
-    pdfsubject={Protocol diagrams for LaTeX},
-    pdfkeywords={bits, bytes, bit fields, communication, network protocol
-      diagrams, LaTeX2e, memory maps},
-    bookmarksopen=true,
-    colorlinks=true,
-    citecolor=darkblue,
-    urlcolor=darkgreen,
-    linkcolor=darkred,
-    menucolor=darkbrown}
-}
+\usepackage{wasysym}
+\IfFileExists{hypdoc.sty}{\usepackage{hypdoc}}{}
+\usepackage{hyperref}%
+
+\definecolor{darkred}{rgb}{0.5,0,0}
+\definecolor{darkgreen}{rgb}{0,0.3,0}
+\definecolor{darkblue}{rgb}{0,0,0.5}
+\definecolor{darkbrown}{rgb}{0.28,0.07,0.07}
+\hypersetup{%
+  pdftitle={The bytefield package},
+  pdfauthor={Scott Pakin <scott+bf@pakin.org>},
+  pdfsubject={Protocol diagrams for LaTeX},
+  pdfkeywords={bits, bytes, bit fields, communication, network protocol
+    diagrams, LaTeX2e, memory maps},
+  bookmarksopen=true,
+  colorlinks=true,
+  citecolor=darkblue,
+  urlcolor=darkgreen,
+  linkcolor=darkred,
+  menucolor=darkbrown}
 \EnableCrossrefs
 \CodelineIndex
 \RecordChanges
@@ -64,7 +66,7 @@
 %</driver>
 % \fi
 %
-% \CheckSum{615}
+% \CheckSum{851}
 %
 % \CharacterTable
 %  {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
@@ -85,25 +87,40 @@
 %
 % \changes{v1.0}{2000/07/02}{Initial version}
 % \changes{v1.1}{2002/09/14}{Restructured the \texttt{.dtx} file}
+% \changes{v1.4}{2011/01/09}{Made assignments to \cs{counting@words}
+%   global to prevent vertical-spacing problems with back-to-back word
+%   groups (bug fix due to Steven R. King)}
+% \changes{v1.4}{2011/01/16}{Split \cs{curlyspace}, \cs{labelspace}, and
+%   \cs{curlyshrinkage} into \texttt{left} and \texttt{right} versions}
+% \changes{v2.0}{2011/01/18}{Made a number of non-backwards-compatible
+%   changes, including replacing \cs{wordgroupr} and \cs{endwordgroupr}
+%   with a \texttt{rightwordgroup} environment and \cs{wordgroupl} and
+%   \cs{endwordgroupl} with a \texttt{leftwordgroup} environment and
+%   also replacing a slew of user-visible lengths and macros with a
+%   single \cs{bytefieldsetup} macro}
 %
 % \GetFileInfo{bytefield.dtx}
 %
 % \DoNotIndex{\&,\{,\}}
 % \DoNotIndex{\addtocounter,\advance}
 % \DoNotIndex{\begin,\begingroup,\bgroup}
-% \DoNotIndex{\catcode,\ch@ck,\count,\cr}
+% \DoNotIndex{\catcode,\ch@ck,\count,\cr,\csname}
 % \DoNotIndex{\DeclareRobustCommand,\def,\dimen,\dimendef}
-% \DoNotIndex{\edef,\egroup,\else,\end,\endgroup,\expandafter}
+% \DoNotIndex{\edef,\egroup,\else,\end,\endcsname,\endgroup,\expandafter}
 % \DoNotIndex{\fi}
 % \DoNotIndex{\gdef,\global}
+% \DoNotIndex{\hspace}
 % \DoNotIndex{\if,\ifnum,\ifx,\ignorespaces,\insc@unt}
-% \DoNotIndex{\let}
-% \DoNotIndex{\newbox,\newcounter,\newenvironment,\newif,\newlength}
-% \DoNotIndex{\newsavebox}
+% \DoNotIndex{\let,\loop}
+% \DoNotIndex{\MessageBreak}
+% \DoNotIndex{\newbox,\newcommand,\newcounter,\newenvironment,\newif}
+% \DoNotIndex{\newlength,\newsavebox,\noexpand}
 % \DoNotIndex{\raisebox,\ratio,\real,\relax,\renewcommand}
+% \DoNotIndex{\par,\protect}
+% \DoNotIndex{\renewenvironment,\repeat}
 % \DoNotIndex{\sbox,\setcounter,\setlength,\settowidth,\space,\string}
 % \DoNotIndex{\the}
-% \DoNotIndex{\usebox}
+% \DoNotIndex{\usebox,\usepackage}
 % \DoNotIndex{\value,\vbox}
 % \DoNotIndex{\wlog}
 % \DoNotIndex{\xdef}
@@ -123,15 +140,6 @@
 %   \end{tabular}\end{lrbox}^^A
 %   \vspace{3ex}\noindent\hspace*{-3em}\fbox{\usebox{\declbox}}\vspace*{2ex}}
 %
-% ^^A  Draw a cute smiley face to use within text (classier than ":-)").
-% \newcommand{\smileyface}{\raisebox{-2pt}{^^A
-% \begin{picture}(9,9)
-%   \put(5,5){\circle{9}}
-%   \put(3.5,7){\circle*{2}}
-%   \put(6.6,7){\circle*{2}}
-%   \put(0,0){\makebox(9,3)[t]{\tiny $\,\smile$}}
-% \end{picture}}}
-%
 % ^^A  Define an ellipsis that permits a subsequent line break.
 % \newcommand{\ellipsis}{$\ldots$\linebreak[0]}
 %
@@ -146,24 +154,110 @@
 % ^^A  Define something like \cs to use within \StopEventually.
 % \DeclareRobustCommand{\cseq}[1]{\texttt{\string#1}}
 %
+% ^^A  Index a package.  This code was adapted from \SpecialEnvIndex.
+% \makeatletter
+% \def\SpecialPkgIndex#1{^^A
+%   \@bsphack
+%     \index{#1\actualchar{\protect\sffamily#1} (package)\encapchar usage}^^A
+%     \index{packages:\levelchar#1\actualchar{\protect\sffamily#1}^^A
+%       \encapchar usage}^^A
+%   \@esphack
+% }
+%
+% ^^A  The following was adapted from hypdoc's redefinition of \SpecialEnvIndex.
+% \expandafter\ifx\csname c@HD@hypercount\endcsname\relax
+% \else
+%   \let\HDorg@SpecialPkgIndex\SpecialPkgIndex
+%   \renewcommand*\SpecialPkgIndex[1]{^^A
+%     \@bsphack
+%     \begingroup
+%       \HD@target
+%       \let\HDorg@encapchar\encapchar
+%       \edef\encapchar usage{^^A
+%         \HDorg@encapchar hdpindex{usage}^^A
+%       }^^A
+%       \HDorg@SpecialPkgIndex{#1}^^A
+%     \endgroup
+%     \@esphack
+%   }
+% \fi
+% \makeatother
+%
+% ^^A  Define a logical style for package names.
+% \DeclareRobustCommand{\pkgname}[1]{^^A
+%   \textsf{#1}^^A
+%   \SpecialPkgIndex{#1}^^A
+% }
+%
+%
+% ^^A  Index an option.  This code was adapted from \SpecialEnvIndex.
+% \makeatletter
+% \def\SpecialOptionIndex#1{^^A
+%   \@bsphack
+%     \index{#1\actualchar{\protect\sffamily#1} (option)\encapchar usage}^^A
+%     \index{options:\levelchar#1\actualchar{\protect\sffamily#1}^^A
+%       \encapchar usage}^^A
+%   \@esphack
+% }
+%
+% ^^A  The following was adapted from hypdoc's redefinition of \SpecialEnvIndex.
+% \expandafter\ifx\csname c@HD@hypercount\endcsname\relax
+% \else
+%   \let\HDorg@SpecialOptionIndex\SpecialOptionIndex
+%   \renewcommand*\SpecialOptionIndex[1]{^^A
+%     \@bsphack
+%     \begingroup
+%       \HD@target
+%       \let\HDorg@encapchar\encapchar
+%       \edef\encapchar usage{^^A
+%         \HDorg@encapchar hdpindex{usage}^^A
+%       }^^A
+%       \HDorg@SpecialOptionIndex{#1}^^A
+%     \endgroup
+%     \@esphack
+%   }
+% \fi
+% \makeatother
+%
+% ^^A  Define a logical style for package-option names.
+% \DeclareRobustCommand{\optname}[1]{^^A
+%   \texttt{#1}^^A
+%   \SpecialOptionIndex{#1}^^A
+% }
+%
 %
 % \begin{abstract}
-% The \texttt{bytefield} package helps the user create illustrations for
+% The \pkgname{bytefield} package helps the user create illustrations for
 % network protocol specifications and anything else that utilizes fields of
 % data.  These illustrations show how the bits and bytes are laid out in a
 % packet or in memory.
 % \end{abstract}
 %
+%
+% \vspace{\baselineskip}
+% \begin{center}
+% \fbox{%
+%   \begin{minipage}{0.65\linewidth}
+%     \textsc{Warning}: \pkgname{bytefield} version~2.\textit{x} breaks
+%     compatibility with older versions of the package.  See
+%     Section~\ref{sec:upgrading} for help porting documents to the new
+%     interface.
+%   \end{minipage}%
+% }
+% \end{center}
+% \vspace{\baselineskip}
+%
+%
 % \section{Introduction}
 %
 % Network protocols are usually specified in terms of a sequence of bits
 % and bytes arranged in a field.  This is portrayed graphically as
 % a grid of boxes.  Each row in the grid represents one word (frequently,
 % 32~bits), and each column represents a bit within a word.
-% The \texttt{bytefield} package makes it easy to typeset these sorts of
+% The \pkgname{bytefield} package makes it easy to typeset these sorts of
 % figures.
 %
-% \texttt{bytefield} lets one draw protocol diagrams that contain:
+% \pkgname{bytefield} lets one draw protocol diagrams that contain:
 %
 % \begin{itemize}
 %   \item Words of any arbitrary number of bits
@@ -174,55 +268,62 @@
 %   \item ``Skipped words'' within fields
 % \end{itemize}
 %
-% Because \texttt{bytefield} draws its figures using only
+% Because \pkgname{bytefield} draws its figures using only
 % the \LaTeX{} \texttt{picture} environment, these figures are not
 % specific to any particular backend, do not require PostScript support,
 % and do not need support from external programs.  Furthermore, unlike an
-% imported graphic, \texttt{bytefield} pictures can include arbitrary
+% imported graphic, \pkgname{bytefield} pictures can include arbitrary
 % \LaTeX{} constructs, such as mathematical equations, |\ref|s and
 % |\cite|s to the surrounding document, and macro calls.
 %
 %
 % \section{Usage}
+% \label{sec:usage}
 %
 % \subsection{Basic commands}
+% \label{sec:basic-cmds}
 %
-% This section explains how to use the \texttt{bytefield} package.
+% This section explains how to use the \pkgname{bytefield} package.
 % It lists all the exported environments, commands, and variables in
-% decreasing order of importance.
+% decreasing order of usefulness.
 %
 % \begin{decl}
-%   |\begin{bytefield}| \marg{bit-width} \\
+%   \SpecialEnvIndex{bytefield}
+%   |\begin{bytefield}| \oarg{parameters} \marg{bit-width} \\
 %   \meta{fields} \\
 %   |\end{bytefield}|
 % \end{decl}
 %
-% The top-level environment is called, not surprisingly,
-% ``|bytefield|''.  It takes one (mandatory) argument, which is the
-% number of bits in each word.  One can think of a \texttt{bytefield} as
-% being analogous to a \texttt{tabular}: words are separated
-% by~|\\|, and fields within a word are separated by~|&|.
+% The \pkgname{bytefield} package's top-level environment is called, not
+% surprisingly, ``|bytefield|''.  It takes one mandatory argument, which
+% is the number of bits in each word, and one optional argument, which
+% is a set of parameters, described in Section~\ref{sec:options}, for
+% formatting the bit-field's layout.  One can think of a |bytefield| as
+% being analogous to a |tabular|: words are separated by~``|\\|'', and
+% fields within a word are separated by~``|&|''.
 %
 % \begin{decl}
-%   |\wordbox| \oarg{sides} \marg{height} \marg{text} \\
-%   |\bitbox| \oarg{sides} \marg{width} \marg{text}
+%   \SpecialUsageIndex{\bitbox}
+%   |\bitbox| \oarg{sides} \marg{width} \marg{text} \\
+%   \SpecialUsageIndex{\wordbox}
+%   |\wordbox| \oarg{sides} \marg{height} \marg{text}
 % \end{decl}
 %
-% The two main commands one uses within a \texttt{bytefield} environment
-% are |\wordbox| and |\bitbox|.  The former typesets a field
-% that is one or more words tall and an entire word wide.
-% The latter typesets a field that is one or more bits wide and a single
-% word tall.
+% The two main commands one uses within a \pkgname{bytefield}
+% environment are |\bitbox| and |\wordbox|.  The former typesets a field
+% that is one or more bits wide and a single word tall.  The latter
+% typesets a field that is one or more words tall and an entire word
+% wide.
 %
-% The optional argument, \meta{sides}, is a list of letters
-% specifying which sides of the field box to draw---|[l]|eft, |[r]|ight,
-% |[t]|op, and/or |[b]|ottom.  The default is ``|lrtb|'' (i.e., all sides
-% are drawn).  \meta{text} is the text to include within the |\wordbox| or
-% |\bitbox|.  It is typeset horizontally centered within a vertically
-% centered |\parbox|.  Hence, words will wrap, and |\\| can
-% be used to break lines manually.
+% The optional argument, \meta{sides}, is a list of letters specifying
+% which sides of the field box to draw---[|l|]eft, [|r|]ight, [|t|]op,
+% and/or [|b|]ottom.  The default is ``|lrtb|'' (i.e.,~all sides are
+% drawn).  \meta{text} is the text to include within the |\bitbox| or
+% |\wordbox|.  It is typeset horizontally centered within a vertically
+% centered |\parbox|.  Hence, words will wrap, and ``|\\|'' can be used
+% to break lines manually.
 %
-% The following example shows how to produce a simple 16-bit-wide byte field:
+% The following example shows how to produce a simple 16-bit-wide field:
 %
 % \begin{verbatim}
 %       \begin{bytefield}{16}
@@ -232,7 +333,7 @@
 %       \end{bytefield}
 % \end{verbatim}
 %
-% The resulting figure looks like this:
+% The resulting bit field looks like this:
 %
 % \begin{bffigure}
 %       \begin{bytefield}{16}
@@ -242,20 +343,22 @@
 %       \end{bytefield}
 % \end{bffigure}
 %
-% It is the user's responsibility to ensure that the total
-% number of bits in each row adds up to the number of bits in a single
-% word (the mandatory argument to the |bytefield| environment).
+% It is the user's responsibility to ensure that the total number of
+% bits in each row adds up to the number of bits in a single word (the
+% mandatory argument to the |bytefield| environment);
+% \pkgname{bytefield} does not currently check for under- or overruns.
 %
-% Within a |\wordbox| or |\bitbox|, the \texttt{bytefield} package
+% Within a |\bitbox| or |\wordbox|, the \pkgname{bytefield} package
 % defines |\height|, |\depth|, |\totalheight|, and |\width| to the
 % corresponding dimensions of the box.  Section~\ref{sec:tricks} gives an
 % example of how these lengths may be utilized.
 %
 % \begin{decl}
+%   \SpecialUsageIndex{\bitheader}
 %   |\bitheader| \oarg{endianness} \marg{bit-positions}
 % \end{decl}
 %
-% To make the figure more readable, it helps to label bit positions across
+% To make the bit field more readable, it helps to label bit positions across
 % the top.  The |\bitheader| command provides a flexible way to do that.
 % The optional argument, \meta{endianness} is one of ``|b|'' or ``|l|''
 % and specifies whether the bits in each word are numbered in big-endian
@@ -281,7 +384,7 @@
 %       \end{bytefield}
 % \end{verbatim}
 %
-% The resulting figure looks like this:
+% The resulting bit field looks like this:
 %
 % \begin{bffigure}
 %       \begin{bytefield}{32}
@@ -293,54 +396,62 @@
 %
 %
 % \begin{decl}
-%   |\wordgroupr| \marg{text} \\
-%   |\endwordgroupr| \\
+%   \SpecialEnvIndex{rightwordgroup}
+%   |\begin{rightwordgroup}| \marg{text} \\
+%   \meta{rows of bit boxes and word boxes} \\
+%   |\end{rightwordgroup}| \\
 %   \\
-%   |\wordgroupl| \marg{text} \\
-%   |\endwordgroupl|
+%   \SpecialEnvIndex{leftwordgroup}
+%   |\begin{leftwordgroup}| \marg{text} \\
+%   \meta{rows of bit boxes and word boxes} \\
+%   |\end{leftwordgroup}|
 % \end{decl}
 %
 % When a set of words functions as a single, logical unit, it helps to
 % group these words together visually.  All words defined between
-% |\wordgroupr| and |\endwordgroupr| will be labeled on the right with
-% \meta{text}.  Similarly, all words defined between
-% |\wordgroupl| and |\endwordgroupl| will be labeled on the left with
-% \meta{text}.  |\wordgroup|\textit{x} must lie at the beginning of a row
-% (i.e., right after a |\\|), and |\endwordgroup|\textit{x} must lie right
-% \emph{before} the end of the row (i.e., right before a |\\|).
-%
-% |\wordgroupr|\ellipsis|\endwordgroupr| and
-% |\wordgroupl|\ellipsis|\endwordgroupl| can overlap each other.
+% |\begin{rightwordgroup}| and |\end{rightwordgroup}| will be labeled on
+% the right with \meta{text}.  Similarly, all words defined between
+% |\begin{leftwordgroup}| and |\end{leftwordgroup}| will be labeled on
+% the left with \meta{text}.  |\begin{|\meta{side}|wordgroup}| must lie
+% at the beginning of a row (i.e.,~right after a ``|\\|''), and
+% |\end{|\meta{side}|wordgroup}| must lie right \emph{before} the end of
+% the row (i.e.,~right before a ``|\\|'').
+%
+% Unlike other \LaTeX\ environments, |rightwordgroup| and
+% |leftwordgroup| do not have to nest properly with each other.
 % However, they cannot overlap themselves.  In other words,
-% |\wordgroupr|\ellipsis|\wordgroupl|\ellipsis|\endwordgroupr|\ellipsis|\endwordgroupl|
-% is a valid sequence, but
-% |\wordgroupr|\ellipsis|\wordgroupr|\ellipsis|\endwordgroupr|\ellipsis|\endwordgroupr|
-% is not.
+% |\begin{rightwordgroup}|\ellipsis |\begin{leftwordgroup}|\ellipsis
+% |\end{rightwordgroup}|\ellipsis |\end{leftwordgroup}| is a valid
+% sequence, but |\begin{rightwordgroup}|\ellipsis
+% |\begin{rightwordgroup}|\ellipsis |\end{rightwordgroup}|\ellipsis
+% |\end{rightwordgroup}| is not.
 %
-% The following example shows how to use |\wordgroupr| and |\endwordgroupr|:
+% The following example presents the basic usage of
+% |\begin{rightwordgroup}| and |\end{rightwordgroup}|:
 %
 % \begin{verbatim}
 %       \begin{bytefield}{16}
 %         \bitheader{0,7,8,15} \\
-%         \wordgroupr{Header}
+%         \begin{rightwordgroup}{Header}
 %           \bitbox{4}{Tag} & \bitbox{12}{Mask} \\
 %           \bitbox{8}{Source} & \bitbox{8}{Destination}
-%         \endwordgroupr \\
+%         \end{rightwordgroup} \\
 %         \wordbox{3}{Data}
 %       \end{bytefield}
 % \end{verbatim}
 %
 % \noindent
-% Note the justaposition of |\\| to |\wordgroupr| and |\endwordgroupr|
-% in the above.  The resulting figure looks like this:
+% Note the juxtaposition of ``|\\|'' to the |\begin{rightwordgroup}| and
+% the |\end{rightwordgroup}| in the above.  The resulting bit field
+% looks like this:
 %
 % \begin{bffigure}
 %       \begin{bytefield}{16}
 %         \bitheader{0,7,8,15} \\
-%         \wordgroupr{Header}
+%         \begin{rightwordgroup}{Header}
 %           \bitbox{4}{Tag} & \bitbox{12}{Mask} \\
 %           \bitbox{8}{Source} & \bitbox{8}{Destination}
-%         \endwordgroupr \\
+%         \end{rightwordgroup} \\
 %         \wordbox{3}{Data}
 %       \end{bytefield}
 % \end{bffigure}
@@ -351,12 +462,12 @@
 % \begin{verbatim}
 %       \begin{bytefield}{16}
 %         \bitheader{0,7,8,15} \\
-%         \wordgroupr{Header}
+%         \begin{rightwordgroup}{Header}
 %           \bitbox{4}{Tag} & \bitbox{12}{Mask} \\
-%           \wordgroupl{Node IDs}
+%           \begin{leftwordgroup}{Node IDs}
 %             \bitbox{8}{Source} & \bitbox{8}{Destination}
-%           \endwordgroupl
-%         \endwordgroupr \\
+%           \end{leftwordgroup}
+%         \end{rightwordgroup} \\
 %         \wordbox{3}{Data}
 %       \end{bytefield}
 % \end{verbatim}
@@ -364,27 +475,31 @@
 % \begin{bffigure}
 %       \begin{bytefield}{16}
 %         \bitheader{0,7,8,15} \\
-%         \wordgroupr{Header}
+%         \begin{rightwordgroup}{Header}
 %           \bitbox{4}{Tag} & \bitbox{12}{Mask} \\
-%           \wordgroupl{Node IDs}
+%           \begin{leftwordgroup}{Node IDs}
 %             \bitbox{8}{Source} & \bitbox{8}{Destination}
-%           \endwordgroupl
-%         \endwordgroupr \\
+%           \end{leftwordgroup}
+%         \end{rightwordgroup} \\
 %         \wordbox{3}{Data}
 %       \end{bytefield}
 % \end{bffigure}
 %
 % \noindent
-% Again, note the justaposition of |\\| to the various word-grouping
+% Because |rightwordgroup| and |leftwordgroup| are not required to nest
+% properly, the resulting bit field would look the same if the
+% |\end{leftwordgroup}| and |\end{rightwordgroup}| were swapped.  Again,
+% note the justaposition of ``|\\|'' to the various word-grouping
 % commands in the above.
 %
 % \begin{decl}
+%   \SpecialUsageIndex{\skippedwords}
 %   |\skippedwords|
 % \end{decl}
 %
 % Draw a graphic representing a number of words that are not shown.
 % |\skippedwords| is intended to work with the \meta{sides} argument
-% to |\wordbox|.  For example:
+% to |\wordbox|, as in the following example:
 %
 % \begin{verbatim}
 %       \begin{bytefield}{16}
@@ -407,44 +522,291 @@
 % \end{bffigure}
 %
 % \begin{decl}
-%   |\bitwidth| \\
-%   |\byteheight|
+%   \SpecialUsageIndex{\bytefieldsetup}
+%   |\bytefieldsetup| \marg{key=value list}
 % \end{decl}
 %
-% The above variables represent the width of each bit and height of each
-% byte in the figure.  Change them with |\setlength| to adjust the size
-% of the figure.  The default value of |\byteheight| is~|2ex|, and the
-% default value of |\bitwidth| is the width of ``|{\tiny 99i}|'',
-% i.e.,~the width of a two-digit number plus a small amount of extra space.
-% This enables |\bitheader| to show two-digit numbers without overlap.
+% Alter the formatting of all subsequent bit fields.
+% Section~\ref{sec:options} describes the possible values for each
+% \meta{key=value} item in the (comma-separated) list that
+% |\bytefieldsetup| accepts as its argument.  Note that changes made
+% with |\bytefieldsetup| are local to their current scope.  Hence, if
+% used within an environment (e.g.,~|figure|), |\bytefieldsetup| does
+% not impact bit fields drawn outside that environment.
+%
+%
+% \subsection{Formatting options}
+% \label{sec:options}
+%
+% A document author can customize many of the \pkgname{bytefield}
+% package's figure-formatting parameters, either globally or on a
+% per-figure basis.  The parameters described below can be specified in
+% any of three locations:
+%
+% \begin{itemize}
+%   \item as package options (i.e.,~in the
+%     |\usepackage|\oarg{options}|{bytefield}| line), which affects all
+%     |bytefield| environments in the entire document,
+%
+%   \item anywhere in the document using the |\bytefieldsetup| command,
+%     which affects all subsequent |bytefield| environments in the
+%     current scope, or
+%
+%   \item as the optional argument to a |\begin{bytefield}|, which
+%     affects only that single bit-field figure.
+% \end{itemize}
+%
+% Unfortunately, \LaTeXe\ tends to abort with a ``\texttt{TeX capacity
+%   exceeded}'' or ``\texttt{Missing \cs{endcsname} inserted}'' error
+% when a control sequence (i.e.,~|\|\meta{name}) or |\|\meta{symbol}) is
+% encountered within the optional argument to |\usepackage|.  Hence,
+% parameters that typically expect a control sequence in their
+% argument---in particular, \optname{bitformatting},
+% \optname{boxformatting}, \optname{leftcurly}, and
+% \optname{rightcurly}---should best be avoided within the
+% |\usepackage|\oarg{options}|{bytefield}| line.
 %
 % \begin{decl}
-%   |\curlyspace| \\
-%   |\labelspace|
+%   \optname{bitwidth} = \meta{length} \\
+%   \optname{bitheight} = \meta{length}
 % \end{decl}
 %
-% |\curlyspace| is the space to insert between the figure and the curly
-% brace preceding a word group (default: |1ex|).  |\labelspace| is the
-% space to insert between the curly brace and the label (default: |0.5ex|).
-% Change these with |\setlength| to adjust the spacing.
+% The above parameters represent the width and height of each bit in a
+% bit field.  The default value of \optname{bitwidth} is the width of
+% ``|{\tiny 99i}|'', i.e.,~the width of a two-digit number plus a small
+% amount of extra space.  This enables |\bitheader| to show two-digit
+% numbers without overlap.  The default value of \optname{bitheight}
+% is~|2ex|, which should allow a normal piece of text to appear within a
+% |\bitbox| or |\wordbox| without abutting the box's top or bottom edge.
+%
+% As a special case, if \optname{bitwidth} is set to the word
+% ``|auto|'', it will be set to the width of ``|99i|'' in the current
+% bit-number formatting (cf.~\optname{bitformatting} below).  This
+% feature provides a convenient way to adjust the bit width after a
+% formatting change.
 %
 % \begin{decl}
-%   |\curlyshrinkage|
+%   \optname{bitformatting} = \meta{command} \emph{or} \marg{commands}
+% \end{decl}
+%
+% The numbers that appear in a bit header are typeset in the
+% \optname{bitformatting} style, which defaults to |\tiny|.  To alter
+% the style of bit numbers in the bit header, set
+% \optname{bitformatting} to a macro that takes a single argument (like
+% |\textbf|) or no arguments (like |\small|).  Groups of commands
+% (e.g.,~|{\large\itshape}|) are also acceptable.
+%
+% When \optname{bitformatting} is set, \optname{bitwidth} usually needs
+% to be recalculated as well to ensure that a correct amount of spacing
+% surrounds each number in the bit header.  As described above, setting
+% |bitwidth=auto| is a convenient shortcut for recalculating the
+% bit-width in the common case of bit fields containing no more than 99
+% bits per line and no particularly wide labels in bit boxes that
+% contain only a few bits.
+%
+% The following example shows how to use \optname{bitformatting} and
+% \optname{bitwidth} to format a bit header with small, boldface text:
+%
+% \begin{verbatim}
+%       \begin{bytefield}[bitformatting={\small\bfseries},bitwidth=auto]{20}
+%         \bitheader[b]{0-19} \\
+%         \bitbox{1}{\tiny F/E} & \bitbox{1}{\tiny T0} & \bitbox{1}{\tiny T1}
+%         & \bitbox{1}{\tiny Fwd} & \bitbox{16}{Data value} \\
+%       \end{bytefield}
+% \end{verbatim}
+%
+% \noindent
+% The resulting bit field looks like this:
+%
+% \begin{bffigure}
+%       \begin{bytefield}[bitformatting={\small\bfseries},bitwidth=auto]{20}
+%         \bitheader[b]{0-19} \\
+%         \bitbox{1}{\tiny F/E} & \bitbox{1}{\tiny T0} & \bitbox{1}{\tiny T1}
+%         & \bitbox{1}{\tiny Fwd} & \bitbox{16}{Data value} \\
+%       \end{bytefield}
+% \end{bffigure}
+%
+% \begin{decl}
+%   \optname{boxformatting} = \meta{command} \emph{or} \marg{commands}
+% \end{decl}
+%
+% The text that appears in a |\bitbox| or |\wordbox| is formatted in the
+% \optname{boxformatting} style, which defaults to |\centering|.  To
+% alter the style of bit numbers in the bit header, set
+% \optname{boxformatting} to a macro that takes a single argument (like
+% |\textbf| but not |\textbf|---see below) or no arguments (like
+% |\small|).  Groups of commands (e.g.,~|{\large\itshape}|) are also
+% acceptable.
+%
+% If \optname{boxformatting} is set to a macro that takes an argument,
+% the macro must be defined as a ``long'' macro, which means it can
+% accept more than one paragraph as an argument.  Commands defined with
+% |\newcommand| are automatically made long, but commands defined with
+% |\newcommand*| are not.  \LaTeX's |\text|\dots\ formatting commands
+% (e.g.,~|\textbf|) are not long and therefore cannot be used directly
+% in \optname{boxformatting}; use the zero-argument versions
+% (e.g.,~|\bfseries|) instead.
+%
+% The following example shows how to use \optname{boxformatting} to
+% format the text within each box horizontally centered and italicized:
+%
+% \begin{verbatim}
+%       \begin{bytefield}[boxformatting={\centering\itshape},
+%                         bitwidth=1.5em]{20}
+%         \bitheader[b]{0-19} \\
+%         \bitbox{1}{\tiny F/E} & \bitbox{1}{\tiny T0} & \bitbox{1}{\tiny T1}
+%         & \bitbox{1}{\tiny Fwd} & \bitbox{16}{Data value} \\
+%       \end{bytefield}
+% \end{verbatim}
+%
+% \noindent
+% The resulting bit field looks like this:
+%
+% \begin{bffigure}
+%       \begin{bytefield}[boxformatting={\centering\itshape},
+%                         bitwidth=1.5em]{20}
+%         \bitheader[b]{0-19} \\
+%         \bitbox{1}{\tiny F/E} & \bitbox{1}{\tiny T0} & \bitbox{1}{\tiny T1}
+%         & \bitbox{1}{\tiny Fwd} & \bitbox{16}{Data value} \\
+%       \end{bytefield}
+% \end{bffigure}
+%
+% \begin{decl}
+%   \optname{leftcurly} = \meta{delimiter} \\
+%   \optname{rightcurly} = \meta{delimiter}
+% \end{decl}
+%
+% Word groups are normally indicated by a curly brace spanning all of
+% its rows.  However, the curly brace can be replaced by any other
+% extensible math delimiter (i.e.,~a symbol that can meaningfully follow
+% |\left| or |\right| in math mode) via a suitable redefinition of
+% \optname{leftcurly} or \optname{rightcurly}.  As in math mode, ``|.|''
+% means ``no symbol'', as in the following example (courtesy of
+% Steven~R. King):
+%
+% \begin{verbatim}
+%       \begin{bytefield}[rightcurly=., rightcurlyspace=0pt]{32}
+%         \bitheader[b]{0,7,8,15,16,23,24,31} \\
+%         \begin{rightwordgroup}{0Ch}
+%           \bitbox{8}{Byte 15 \\ \tiny (highest address)}
+%           & \bitbox{8}{Byte 14}
+%           & \bitbox{8}{Byte 13}
+%           & \bitbox{8}{Byte 12}
+%         \end{rightwordgroup} \\
+%         \begin{rightwordgroup}{08h}
+%           \bitbox{32}{Long 0}
+%         \end{rightwordgroup} \\
+%         \begin{rightwordgroup}{04h}
+%           \bitbox{16}{Word 1} & \bitbox{16}{Word 0}
+%         \end{rightwordgroup} \\
+%         \begin{rightwordgroup}{00h}
+%           \bitbox{8}{Byte 3}
+%           & \bitbox{8}{Byte 2}
+%           & \bitbox{8}{Byte 1}
+%           & \bitbox{8}{Byte 0 \\ \tiny (lowest address)}
+%         \end{rightwordgroup} \\
+%       \end{bytefield}
+% \end{verbatim}
+%
+% \begin{bffigure}
+%       \begin{bytefield}[rightcurly=., rightcurlyspace=0pt]{32}
+%         \bitheader[b]{0,7,8,15,16,23,24,31} \\
+%         \begin{rightwordgroup}{0Ch}
+%           \bitbox{8}{Byte 15 \\ \tiny (highest address)}
+%           & \bitbox{8}{Byte 14}
+%           & \bitbox{8}{Byte 13}
+%           & \bitbox{8}{Byte 12}
+%         \end{rightwordgroup} \\
+%         \begin{rightwordgroup}{08h}
+%           \bitbox{32}{Long 0}
+%         \end{rightwordgroup} \\
+%         \begin{rightwordgroup}{04h}
+%           \bitbox{16}{Word 1} & \bitbox{16}{Word 0}
+%         \end{rightwordgroup} \\
+%         \begin{rightwordgroup}{00h}
+%           \bitbox{8}{Byte 3}
+%           & \bitbox{8}{Byte 2}
+%           & \bitbox{8}{Byte 1}
+%           & \bitbox{8}{Byte 0 \\ \tiny (lowest address)}
+%         \end{rightwordgroup} \\
+%       \end{bytefield}
+% \end{bffigure}
+%
+% \begin{decl}
+%   \optname{leftcurlyspace} = \meta{length} \\
+%   \optname{rightcurlyspace} = \meta{length} \\
+%   \optname{curlyspace} = \meta{length}
+% \end{decl}
+%
+% \optname{leftcurlyspace} and \optname{rightcurlyspace} specify the
+% space to insert between the bit field and the curly brace in a left or
+% right word group (default:~|1ex|).  Setting \optname{curlyspace} is a
+% shortcut for setting both \optname{leftcurlyspace} and
+% \optname{rightcurlyspace} to the same value.
+%
+% \begin{decl}
+%   |leftlabelspace| = \meta{length} \\
+%   |rightlabelspace| = \meta{length} \\
+%   |labelspace| = \meta{length}
+% \end{decl}
+%
+% |leftlabelspace| and |rightlabelspace| specify the space to insert
+% between the curly brace and the text label in a left or right word
+% group (default:~|0.5ex|).  Setting |labelspace| is a shortcut for
+% setting both |leftlabelbrace| and |rightlabelspace| to the same value.
+%
+% \bigskip
+%
+% Figure~\ref{fig:rightspace} illustrates the juxtaposition of
+% \optname{rightcurlyspace} and |rightlabelspace| to a word group and
+% its label.  The \optname{leftcurlyspace} and |leftlabelspace|
+% parameters are symmetric.
+%
+% \begin{figure}[htbp]
+%   \[
+%   \begin{array}{*5{@{}c}@{}}
+%     \cline{1-1}
+%     \multicolumn{1}{c|}{\cdots\quad\meta{bit-field rows}}
+%     &
+%     & \left.\rule{0pt}{3ex}\right\}
+%     &
+%     & \meta{label} \\[2ex] \cline{1-1}
+%     & \underbrace{\hspace*{6em}}_{\mathtt{rightcurlyspace}}
+%     &
+%     & \underbrace{\hspace*{6em}}_{\mathtt{rightlabelspace}} \\
+%   \end{array}
+%   \]
+%   \caption{Role of \texttt{rightcurlyspace} and \texttt{rightlabelspace}}
+%   \label{fig:rightspace}
+% \end{figure}
+%
+% \begin{decl}
+%   \optname{leftcurlyshrinkage} = \meta{length} \\
+%   \optname{rightcurlyshrinkage} = \meta{length} \\
+%   \optname{curlyshrinkage} = \meta{length}
 % \end{decl}
 %
 % In \TeX/\LaTeX, the height of a curly brace does not include the tips.
 % Hence, in a word group label, the tips of the curly brace will extend
-% beyond the height of the word group.  |\curlyshrinkage| is an amount by
-% which to reduce the height of curly braces in labels.  It is set to |5pt|,
-% and it is extremely unlikely that one would ever need to change it.
-% Nevertheless, it is documented here in case the document is typeset with
-% a math font containing radically different curly braces from the ones
-% that come with \TeX/\LaTeX.
+% beyond the height of the word group.
+% \optname{leftcurlyshrinkage}\slash \optname{rightcurlyshrinkage} is an
+% amount by which to reduce the height of the curly brace in a
+% left\slash right word group's label.  Setting \optname{curlyshrinkage}
+% is a shortcut for setting both \optname{leftcurlyshrinkage} and
+% \optname{rightcurlyshrinkage} to the same value.  Shrinkages default
+% to~|5pt|, and it is extremely unlikely that one would ever need to
+% change them.  Nevertheless, these parameters are included here in case
+% a document is typeset with a math font containing radically different
+% curly braces from the ones that come with \TeX/\LaTeX\ or that
+% replaces the curly braces (using \optname{leftcurly}\slash
+% \optname{rightcurly}, described above) with symbols of substantially
+% different heights.
+%
 %
 % \subsection{Common tricks}
 % \label{sec:tricks}
 %
-% This section shows some clever ways to use \texttt{bytefield}'s commands
+% This section shows some clever ways to use \pkgname{bytefield}'s commands
 % to produce some useful effects.
 %
 % \paragraph{Odd-sized fields}
@@ -469,8 +831,8 @@
 % \end{bffigure}
 %
 % \paragraph{Ellipses}
-% To skip words from the middle of enumerated data, put some |\vdots|
-% in a |\wordbox| with empty \meta{sides}:
+% To skip words that appear the middle of enumerated data, put some
+% |\vdots| in a |\wordbox| with empty \meta{sides}:
 %
 % \begin{verbatim}
 %       \begin{bytefield}{16}
@@ -508,7 +870,7 @@
 %
 % \newsavebox{\bitwidthOK}
 % \begin{lrbox}{\bitwidthOK}
-%   \settowidth{\bitwidth}{OK~}\relax
+%   \bytefieldsetup{bitwidth=\widthof{OK~}}\relax
 %   \begin{bytefield}{8}
 %     \bitbox{1}{OK} & \bitbox{7}{Data} \\
 %   \end{bytefield}
@@ -539,16 +901,18 @@
 %
 % \begin{tabular}{ll}
 %   \emph{Default}: & \raisebox{-4ex}{\usebox{\defaultOK}} \\
-%   |\settowidth{\bitwidth}{OK~}|: & \raisebox{-4ex}{\usebox{\bitwidthOK}} \\
+%   |\bytefieldsetup{%|
+%   & \multirow{2}*{\raisebox{-4ex}{\usebox{\bitwidthOK}}} \\
+%   |  bitwidth=\widthof{OK~}}|: & \\[2ex]
 %   |\tiny OK|: & \raisebox{-4ex}{\usebox{\tinyOK}} \\
 %   |\tiny O \\ K|: & \raisebox{-4ex}{\usebox{\verticalOK}} \\
 %   |\rotatebox{90}{\small OK}|: & \raisebox{-4ex}{\usebox{\rotateOK}} \\
 % \end{tabular}
 %
 % \paragraph{Unused bits}
-% Because |\width| and |\height| are defined within |\bitbox|es (also
-% |\wordbox|es), we can represent unused bits by filling a |\bitbox|
-% with a rule of size |\width|~$\times$ |\height|:
+% Because |\width| and |\height| are defined within bit boxes (also word
+% boxes), we can represent unused bits by filling a |\bitbox| with a
+% rule of size |\width|~$\times$ |\height|:
 %
 % \begin{verbatim}
 %       \begin{bytefield}{32}
@@ -571,7 +935,7 @@
 % \end{bffigure}
 %
 % \noindent
-% The effect is much better when the \texttt{color} package is used to
+% The effect is much better when the \pkgname{color} package is used to
 % draw the unused bits in color.  (Gray looks nice.)
 %
 % \begin{verbatim}
@@ -596,6 +960,120 @@
 %       \end{bytefield}
 % \end{bffigure}
 %
+% \paragraph{Aligning text on the baseline}
+% Because \pkgname{bytefield} internally uses \LaTeX's |picture|
+% environment and that environment's |\makebox| command to draw bit
+% boxes and word boxes, the text within a box is centered vertically
+% with no attention paid to the text's baseline.  As a result, some bit
+% fields appear somewhat askew:
+%
+% \begin{verbatim}
+%       \begin{bytefield}[bitwidth=1.5em]{2}
+%         \bitbox{1}{M} & \bitbox{1}{y} \\
+%       \end{bytefield}
+% \end{verbatim}
+%
+% \begin{bffigure}
+%       \begin{bytefield}[bitwidth=1.5em]{2}
+%         \bitbox{1}{M} & \bitbox{1}{y} \\
+%       \end{bytefield}
+% \end{bffigure}
+%
+% A solution is to use the \optname{boxformatting} option to trick
+% |\makebox| into thinking that all text has the same height and depth.
+% Here we use |\raisebox| to indicate that all text is as tall as a
+% ``|W|'' and does not descend at all below the baseline:
+%
+% \begin{verbatim}
+%       \newlength{\maxheight}
+%       \setlength{\maxheight}{\heightof{W}}
+%
+%       \newcommand{\baselinealign}[1]{%
+%         \centering
+%         \raisebox{0pt}[\maxheight][0pt]{#1}%
+%       }
+%
+%       \begin{bytefield}[boxformatting=\baselinealign,
+%                         bitwidth=1.5em]{2}
+%         \bitbox{1}{M} & \bitbox{1}{y} \\
+%       \end{bytefield}
+% \end{verbatim}
+%
+% \begin{bffigure}
+%       \newlength{\maxheight}
+%       \setlength{\maxheight}{\heightof{W}}
+%       \newcommand{\baselinealign}[1]{%
+%         \centering
+%         \raisebox{0pt}[\maxheight][0pt]{#1}%
+%       }
+%       \begin{bytefield}[boxformatting=\baselinealign,
+%                         bitwidth=1.5em]{2}
+%         \bitbox{1}{M} & \bitbox{1}{y} \\
+%       \end{bytefield}
+% \end{bffigure}
+%
+% \paragraph{Register contents}
+% Sometimes, rather than listing the \emph{meaning} of each bit field
+% within each |\bitbox| or |\wordbox|, it may be desirable to list the
+% \emph{contents}, with the meaning described in an additional label
+% above each bit number in the bit header.  Although the
+% \pkgname{register} package is more suited to this form of layout,
+% \pkgname{bytefield} can serve in a pinch with the help of the
+% |\turnbox| macro from the \pkgname{rotating} package:
+%
+% \begin{verbatim}
+%      \newcommand{\bitlabel}[2]{%
+%        \bitbox[]{#1}{%
+%          \raisebox{0pt}[4ex][0pt]{%
+%            \turnbox{45}{\fontsize{7}{7}\selectfont#2}%
+%          }%
+%        }%
+%      }
+%
+%      \begin{bytefield}[bitwidth=1em]{16}
+%         \bitlabel{1}{Carry} & \bitlabel{1}{Reserved} &
+%         \bitlabel{1}{Parity} & \bitlabel{1}{Reserved} &
+%         \bitlabel{1}{Adjust} & \bitlabel{1}{Reserved} &
+%         \bitlabel{1}{Zero} & \bitlabel{1}{Sign} &
+%         \bitlabel{1}{Trap} & \bitlabel{1}{Interrupt enable} &
+%         \bitlabel{1}{Direction} & \bitlabel{1}{Overflow} &
+%         \bitlabel{2}{I/O privilege level (12--13)} &
+%         \bitlabel{1}{Nested task} & \bitlabel{1}{Reserved} \\
+%         \bitheader{0-15} \\
+%         \bitbox{1}{0} & \bitbox{1}{1} & \bitbox{1}{0} & \bitbox{1}{0} &
+%         \bitbox{1}{0} & \bitbox{1}{0} & \bitbox{1}{0} & \bitbox{1}{1} &
+%         \bitbox{1}{0} & \bitbox{1}{1} & \bitbox{1}{0} & \bitbox{1}{0} &
+%         \bitbox{1}{0} & \bitbox{1}{0} & \bitbox{1}{0} & \bitbox{1}{0} \\
+%       \end{bytefield}
+% \end{verbatim}
+%
+% \vspace{3\baselineskip}   ^^A  Allow extra room for the rotated headers.
+% \begin{bffigure}
+%      \newcommand{\bitlabel}[2]{%
+%        \bitbox[]{#1}{%
+%          \raisebox{0pt}[4ex][0pt]{%
+%            \turnbox{45}{\fontsize{7}{7}\selectfont#2}%
+%          }%
+%        }%
+%      }
+%      \begin{bytefield}[bitwidth=1em]{16}
+%         \bitlabel{1}{Carry} & \bitlabel{1}{Reserved} &
+%         \bitlabel{1}{Parity} & \bitlabel{1}{Reserved} &
+%         \bitlabel{1}{Adjust} & \bitlabel{1}{Reserved} &
+%         \bitlabel{1}{Zero} & \bitlabel{1}{Sign} &
+%         \bitlabel{1}{Trap} & \bitlabel{1}{Interrupt enable} &
+%         \bitlabel{1}{Direction} & \bitlabel{1}{Overflow} &
+%         \bitlabel{2}{I/O privilege level (12--13)} &
+%         \bitlabel{1}{Nested task} & \bitlabel{1}{Reserved} \\
+%         \bitheader{0-15} \\
+%         \bitbox{1}{0} & \bitbox{1}{1} & \bitbox{1}{0} & \bitbox{1}{0} &
+%         \bitbox{1}{0} & \bitbox{1}{0} & \bitbox{1}{0} & \bitbox{1}{1} &
+%         \bitbox{1}{0} & \bitbox{1}{1} & \bitbox{1}{0} & \bitbox{1}{0} &
+%         \bitbox{1}{0} & \bitbox{1}{0} & \bitbox{1}{0} & \bitbox{1}{0} \\
+%       \end{bytefield}
+% \end{bffigure}
+%
+%
 % \subsection{Not-so-common tricks}
 %
 % \paragraph{Colored fields}
@@ -614,9 +1092,7 @@
 %         \definecolor{lightgreen}{rgb}{0.64,1,0.71}
 %         \definecolor{lightred}{rgb}{1,0.7,0.71}
 %
-%         \settowidth{\byteheight}{~Sign~}
-%         \setlength{\bitwidth}{\baselineskip}
-%         \begin{bytefield}{32}
+%         \begin{bytefield}[bitheight=\widthof{~Sign~}]{32}
 %           \bitheader[b]{31,23,0} \\
 %           \colorbitbox{lightcyan}{1}{\rotatebox{90}{Sign}} &
 %           \colorbitbox{lightgreen}{8}{Exponent} &
@@ -625,55 +1101,212 @@
 %       \endgroup
 % \end{verbatim}
 %
-% \begin{center}
-% \small
-% \newcommand{\colorbitbox}[3]{%
-%   \rlap{\bitbox{#2}{\color{#1}\rule{\width}{\height}}}^^A
-%   \bitbox{#2}{#3}}
-% \definecolor{lightcyan}{rgb}{0.84,1,1}
-% \definecolor{lightgreen}{rgb}{0.64,1,0.71}
-% \definecolor{lightred}{rgb}{1,0.7,0.71}
-%
-% \settowidth{\byteheight}{~Sign~}
-% \setlength{\bitwidth}{\baselineskip}
-% \begin{bytefield}{32}
-%   \bitheader[b]{31,23,0} \\
-%   \colorbitbox{lightcyan}{1}{\rotatebox{90}{Sign}} &
-%   \colorbitbox{lightgreen}{8}{Exponent} &
-%   \colorbitbox{lightred}{23}{Mantissa} \\
-% \end{bytefield}
-% \end{center}
+% \begin{bffigure}
+%       \begingroup
+%         \small
+%         \newcommand{\colorbitbox}[3]{^^A
+%           \rlap{\bitbox{#2}{\color{#1}\rule{\width}{\height}}}^^A
+%           \bitbox{#2}{#3}}^^A
+%         \definecolor{lightcyan}{rgb}{0.84,1,1}^^A
+%         \definecolor{lightgreen}{rgb}{0.64,1,0.71}^^A
+%         \definecolor{lightred}{rgb}{1,0.7,0.71}^^A
+%         \bytefieldsetup{bitheight=\widthof{~Sign~}}^^A
+%         \begin{bytefield}[bitheight=\widthof{~Sign~}]{32}
+%           \bitheader[b]{31,23,0} \\
+%           \colorbitbox{lightcyan}{1}{\rotatebox{90}{Sign}} &
+%           \colorbitbox{lightgreen}{8}{Exponent} &
+%           \colorbitbox{lightred}{23}{Mantissa} \\
+%         \end{bytefield}
+%       \endgroup
+% \end{bffigure}
+%
+% \paragraph{Renumbered bit headers}
+% The |\bitheader| macro always numbers bits starting from~0.  However,
+% one may occasionally want to begin numbering from a different value.
+% (This was in fact a feature request from Chris L'Esperance.)  The way
+% to accomplish this is to define a macro that adds a value to its
+% argument and specify this macro to the \optname{bitformatting}
+% parameter.  This works because the argument passed to a macro named by
+% \optname{bitformatting} is always numeric except when called from
+% |bitwidth=auto|.  (Caveat: This happens automatically at the
+% |\begin{document}|.)  However, \pkgname{bytefield} sometimes passes a
+% \optname{bitformatting}-named macro the value~|1234567890| to measure
+% the height of a formatted bit number.  The examples below include a
+% case in which this value needs to be checked explicitly to ensure that
+% the height is correct even when the formatted number is rotated by
+% 90\textdegree.
+%
+% \begin{verbatim}
+%       \begin{bytefield}{16}
+%         \bitheader{0-15} \\
+%         \bitbox{8}{Header} & \bitbox{8}{First byte} \\
+%       \end{bytefield}
+% \end{verbatim}
+%
+% \begin{bffigure}
+%       \begin{bytefield}{16}
+%         \bitheader{0-15} \\
+%         \bitbox{8}{Header} & \bitbox{8}{First byte} \\
+%       \end{bytefield}
+% \end{bffigure}
+%
+% \begin{verbatim}
+%       \newcommand{\formatplusXVI}[1]{%
+%         \tiny
+%         \count10=#1
+%         \advance\count10 by 16
+%         \the\count10
+%       }
+%       \begin{bytefield}[bitformatting=\formatplusXVI]{16}
+%         \bitheader{0-15} \\
+%         \bitbox{8}{Second byte} & \bitbox{8}{Third byte} \\
+%       \end{bytefield}
+% \end{verbatim}
+%
+% \begin{bffigure}
+%       \newcommand{\formatplusXVI}[1]{%
+%         \tiny
+%         \count10=#1
+%         \advance\count10 by 16
+%         \the\count10
+%       }
+%       \begin{bytefield}[bitformatting=\formatplusXVI]{16}
+%         \bitheader{0-15} \\
+%         \bitbox{8}{Second byte} & \bitbox{8}{Third byte} \\
+%       \end{bytefield}
+% \end{bffigure}
+%
+% \begin{verbatim}
+%       \newcommand{\formatplusMMMMMMMMCLXXVI}[1]{%
+%         \tiny
+%         \count10=#1
+%         \ifnum\count10=1234567890
+%           \rotatebox[origin=B]{90}{8191}%
+%         \else
+%           \advance\count10 by 8176
+%           \rotatebox[origin=B]{90}{\the\count10}%
+%         \fi
+%       }
+%
+%       \begin{bytefield}[bitformatting=\formatplusMMMMMMMMCLXXVI]{16}
+%         \bitheader{0-15} \\
+%         \bitbox{8}{1022nd byte} & \bitbox{8}{Trailer} \\
+%       \end{bytefield}
+% \end{verbatim}
+%
+% \begin{bffigure}
+%       \newcommand{\formatplusMMMMMMMMCLXXVI}[1]{%
+%         \tiny
+%         \count10=#1
+%         \ifnum\count10=1234567890
+%           \rotatebox[origin=B]{90}{8191}%
+%         \else
+%           \advance\count10 by 8176
+%           \rotatebox[origin=B]{90}{\the\count10}%
+%         \fi
+%       }
+%       \begin{bytefield}[bitformatting=\formatplusMMMMMMMMCLXXVI]{16}
+%         \bitheader{0-15} \\
+%         \bitbox{8}{1022nd byte} & \bitbox{8}{Trailer} \\
+%       \end{bytefield}
+% \end{bffigure}
+%
+% As an even trickier example of modifying bit numbers, the following
+% shows how to \emph{conditionally} modify the bit number: If the number
+% is |1234567890| (for \pkgname{bytefield}'s bit-height calculation, the
+% number is used as is; numbers greater than~9 are increased by 48;
+% numbers less than~4 are unmodified; the number~6 is replaced by an
+% ellipsis; and all other numbers are discarded.
+%
+% \begin{verbatim}
+%       \newcommand{\fakesixtyfourbits}[1]{%
+%         \tiny
+%         \ifnum#1=1234567890
+%           #1
+%         \else
+%           \ifnum#1>9
+%             \count32=#1
+%             \advance\count32 by 48
+%             \the\count32%
+%           \else
+%             \ifnum#1<4
+%               #1%
+%             \else
+%               \ifnum#1=6
+%                 $\cdots$%
+%               \fi
+%             \fi
+%           \fi
+%         \fi
+%       }
+%       \begin{bytefield}[%
+%           bitwidth=\widthof{\tiny Fwd~},
+%           bitformatting=\fakesixtyfourbits]{16}
+%         \bitheader[b]{0-15} \\
+%         \bitbox{1}{\tiny F/E} & \bitbox{1}{\tiny T0} & \bitbox{1}{\tiny T1}
+%         & \bitbox{1}{\tiny Fwd} & \bitbox{12}{Data value} \\
+%       \end{bytefield}
+% \end{verbatim}
+%
+% \begin{bffigure}
+%       \newcommand{\fakesixtyfourbits}[1]{%
+%         \tiny
+%         \ifnum#1=1234567890
+%           #1
+%         \else
+%           \ifnum#1>9
+%             \count32=#1
+%             \advance\count32 by 48
+%             \the\count32%
+%           \else
+%             \ifnum#1<4
+%               #1%
+%             \else
+%               \ifnum#1=6
+%                 $\cdots$%
+%               \fi
+%             \fi
+%           \fi
+%         \fi
+%       }
+%       \begin{bytefield}[%
+%           bitwidth=\widthof{\tiny Fwd~},
+%           bitformatting=\fakesixtyfourbits]{16}
+%         \bitheader[b]{0-15} \\
+%         \bitbox{1}{\tiny F/E} & \bitbox{1}{\tiny T0} & \bitbox{1}{\tiny T1}
+%         & \bitbox{1}{\tiny Fwd} & \bitbox{12}{Data value} \\
+%       \end{bytefield}
+% \end{bffigure}
 %
 % \paragraph{Memory-map diagrams}
-% While certainly not the intended purpose of the \texttt{bytefield}
-% package, one can utilize |\wordbox|es with empty \meta{sides} and
+% While certainly not the intended purpose of the \pkgname{bytefield}
+% package, one can utilize word boxes with empty \meta{sides} and
 % word labels to produce memory-map diagrams:
 %
 % \begin{verbatim}
-%       \setlength{\byteheight}{4\baselineskip}
 %       \newcommand{\descbox}[2]{\parbox[c][3.8\baselineskip]{0.95\width}{%
 %         \raggedright #1\vfill #2}}
-%       \begin{bytefield}{32}
-%         \wordgroupr{Partition 4}
+%       \begin{bytefield}[bitheight=4\baselineskip]{32}
+%         \begin{rightwordgroup}{Partition 4}
 %           \bitbox[]{8}{\texttt{0xFFFFFFFF} \\[2\baselineskip]
 %             \texttt{0xC0000000}} &
 %           \bitbox{24}{\descbox{1\,GB area for VxDs, memory manager,
 %             file system code; shared by all processes.}{Read/writable.}}
-%         \endwordgroupr \\
-%         \wordgroupr{Partition 3}
+%         \end{rightwordgroup} \\
+%         \begin{rightwordgroup}{Partition 3}
 %           \bitbox[]{8}{\texttt{0xBFFFFFFF} \\[2\baselineskip]
 %             \texttt{0x80000000}} &
 %           \bitbox{24}{\descbox{1\,GB area for memory-mapped files,
 %             shared system \textsc{dll}s, file system code; shared by all
 %             processes.}{Read/writable.}}
-%         \endwordgroupr \\
-%         \wordgroupr{Partition 2}
+%         \end{rightwordgroup} \\
+%         \begin{rightwordgroup}{Partition 2}
 %           \bitbox[]{8}{\texttt{0x7FFFFFFF} \\[2\baselineskip]
 %             \texttt{0x00400000}} &
 %           \bitbox{24}{\descbox{$\sim$2\,GB area private to process,
 %              process code, and data.}{Read/writable.}}
-%         \endwordgroupr \\
-%         \wordgroupr{Partition 1}
+%         \end{rightwordgroup} \\
+%         \begin{rightwordgroup}{Partition 1}
 %           \bitbox[]{8}{\texttt{0x003FFFFF} \\[2\baselineskip]
 %             \texttt{0x00001000}} &
 %           \bitbox{24}{\descbox{4\,MB area for MS-DOS and Windows~3.1
@@ -683,34 +1316,33 @@
 %           \bitbox{24}{\descbox{4096~byte area for MS-DOS and Windows~3.1
 %             compatibility.}{Protected---catches \textsc{null}
 %             pointers.}}
-%         \endwordgroupr \\
+%         \end{rightwordgroup} \\
 % \end{verbatim}
 %
 % \begin{bffigure}
-%       \setlength{\byteheight}{4\baselineskip}
 %       \newcommand{\descbox}[2]{\parbox[c][3.8\baselineskip]{0.95\width}{%
 %         \raggedright #1\vfill #2}}
-%       \begin{bytefield}{32}
-%         \wordgroupr{Partition 4}
+%       \begin{bytefield}[bitheight=4\baselineskip]{32}
+%         \begin{rightwordgroup}{Partition 4}
 %           \bitbox[]{8}{\texttt{0xFFFFFFFF} \\[2\baselineskip]
 %             \texttt{0xC0000000}} &
 %           \bitbox{24}{\descbox{1\,GB area for VxDs, memory manager,
 %             file system code; shared by all processes.}{Read/writable.}}
-%         \endwordgroupr \\
-%         \wordgroupr{Partition 3}
+%         \end{rightwordgroup} \\
+%         \begin{rightwordgroup}{Partition 3}
 %           \bitbox[]{8}{\texttt{0xBFFFFFFF} \\[2\baselineskip]
 %             \texttt{0x80000000}} &
 %           \bitbox{24}{\descbox{1\,GB area for memory-mapped files,
 %             shared system \textsc{dll}s, file system code; shared by all
 %             processes.}{Read/writable.}}
-%         \endwordgroupr \\
-%         \wordgroupr{Partition 2}
+%         \end{rightwordgroup} \\
+%         \begin{rightwordgroup}{Partition 2}
 %           \bitbox[]{8}{\texttt{0x7FFFFFFF} \\[2\baselineskip]
 %             \texttt{0x00400000}} &
 %           \bitbox{24}{\descbox{$\sim$2\,GB area private to process, process
 %             code, and data.}{Read/writable.}}
-%         \endwordgroupr \\
-%         \wordgroupr{Partition 1}
+%         \end{rightwordgroup} \\
+%         \begin{rightwordgroup}{Partition 1}
 %           \bitbox[]{8}{\texttt{0x003FFFFF} \\[2\baselineskip]
 %             \texttt{0x00001000}} &
 %           \bitbox{24}{\descbox{4\,MB area for MS-DOS and Windows~3.1
@@ -720,21 +1352,20 @@
 %           \bitbox{24}{\descbox{4096~byte area for MS-DOS and Windows~3.1
 %             compatibility.}{Protected---catches \textsc{null}
 %             pointers.}}
-%         \endwordgroupr \\
+%         \end{rightwordgroup} \\
 %       \end{bytefield}
 % \end{bffigure}
 %
 %
 % \subsection{Putting it all together}
 %
-% The following code showcases most of \texttt{bytefield}'s features in a
+% The following code showcases most of \pkgname{bytefield}'s features in a
 % single figure.
 %
 % \begin{verbatim}
-%       \setlength{\byteheight}{2.5\baselineskip}
-%       \begin{bytefield}{32}
+%       \begin{bytefield}[bitheight=2.5\baselineskip]{32}
 %         \bitheader{0,7,8,15,16,23,24,31} \\
-%         \wordgroupr{\parbox{6em}{\raggedright These words were taken
+%         \begin{rightwordgroup}{\parbox{6em}{\raggedright These words were taken
 %           verbatim from the TCP header definition (RFC~793).}}
 %           \bitbox{4}{Data offset} & \bitbox{6}{Reserved} &
 %             \bitbox{1}{\tiny U\\R\\G} & \bitbox{1}{\tiny A\\C\\K} &
@@ -742,24 +1373,24 @@
 %             \bitbox{1}{\tiny S\\Y\\N} & \bitbox{1}{\tiny F\\I\\N} &
 %             \bitbox{16}{Window} \\
 %           \bitbox{16}{Checksum} & \bitbox{16}{Urgent pointer}
-%         \endwordgroupr \\
+%         \end{rightwordgroup} \\
 %         \wordbox[lrt]{1}{Data octets} \\
 %         \skippedwords \\
 %         \wordbox[lrb]{1}{} \\
-%         \wordgroupl{\parbox{6em}{\raggedright Note that we can display,
+%         \begin{leftwordgroup}{\parbox{6em}{\raggedright Note that we can display,
 %           for example, a misaligned 64-bit value with clever use of the
-%           optional argument to \texttt{\textbackslash wordbox} and
-%           \texttt{\textbackslash bitbox}.}}
+%           optional argument to \texttt{\string\wordbox} and
+%           \texttt{\string\bitbox}.}}
 %           \bitbox{8}{Source} & \bitbox{8}{Destination} &
 %             \bitbox[lrt]{16}{} \\
 %           \wordbox[lr]{1}{Timestamp} \\
-%           \wordgroupr{\parbox{6em}{\raggedright Why two Length fields?
+%           \begin{rightwordgroup}{\parbox{6em}{\raggedright Why two Length fields?
 %             No particular reason.}}
 %             \bitbox[lrb]{16}{} & \bitbox{16}{Length}
-%         \endwordgroupl \\
+%         \end{leftwordgroup} \\
 %             \bitbox{6}{Key} & \bitbox{6}{Value} & \bitbox{4}{Unused} &
 %               \bitbox{16}{Length}
-%           \endwordgroupr \\
+%           \end{rightwordgroup} \\
 %         \wordbox{1}{Total number of 16-bit data words that follow this
 %           header word, excluding the subsequent checksum-type value} \\
 %         \bitbox{16}{Data~1} & \bitbox{16}{Data~2} \\
@@ -777,11 +1408,13 @@
 % \noindent
 % Figure~\ref{fig:complex-diagram} shows the resulting protocol diagram.
 %
+% \newsavebox{\protocoldiagram}
 % \begin{figure}[phtb]
-%       \setlength{\byteheight}{2.5\baselineskip}
-%       \begin{bytefield}{32}
+%    \centering
+%    \begin{lrbox}{\protocoldiagram}
+%       \begin{bytefield}[bitheight=2.5\baselineskip]{32}
 %         \bitheader{0,7,8,15,16,23,24,31} \\
-%         \wordgroupr{\parbox{6em}{\raggedright These words were taken
+%         \begin{rightwordgroup}{\parbox{6em}{\raggedright These words were taken
 %           verbatim from the TCP header definition (RFC~793).}}
 %           \bitbox{4}{Data offset} & \bitbox{6}{Reserved} &
 %             \bitbox{1}{\tiny U\\R\\G} & \bitbox{1}{\tiny A\\C\\K} &
@@ -789,23 +1422,23 @@
 %             \bitbox{1}{\tiny S\\Y\\N} & \bitbox{1}{\tiny F\\I\\N} &
 %             \bitbox{16}{Window} \\
 %           \bitbox{16}{Checksum} & \bitbox{16}{Urgent pointer}
-%         \endwordgroupr \\
+%         \end{rightwordgroup} \\
 %         \wordbox[lrt]{1}{Data octets} \\
 %         \skippedwords \\
 %         \wordbox[lrb]{1}{} \\
-%         \wordgroupl{\parbox{6em}{\raggedright Note that we can display,
+%         \begin{leftwordgroup}{\parbox{6em}{\raggedright Note that we can display,
 %           for example, a misaligned 64-bit value with clever use of the
-%           optional argument to \texttt{\textbackslash wordbox} and
-%           \texttt{\textbackslash bitbox}.}}
+%           optional argument to \texttt{\string\wordbox} and
+%           \texttt{\string\bitbox}.}}
 %           \bitbox{8}{Source} & \bitbox{8}{Destination} & \bitbox[lrt]{16}{} \\
 %           \wordbox[lr]{1}{Timestamp} \\
-%           \wordgroupr{\parbox{6em}{\raggedright Why two Length fields?
+%           \begin{rightwordgroup}{\parbox{6em}{\raggedright Why two Length fields?
 %             No particular reason.}}
 %             \bitbox[lrb]{16}{} & \bitbox{16}{Length}
-%         \endwordgroupl \\
+%         \end{leftwordgroup} \\
 %             \bitbox{6}{Key} & \bitbox{6}{Value} & \bitbox{4}{Unused} &
 %               \bitbox{16}{Length}
-%           \endwordgroupr \\
+%           \end{rightwordgroup} \\
 %         \wordbox{1}{Total number of 16-bit data words that follow this
 %           header word, excluding the subsequent checksum-type value} \\
 %         \bitbox{16}{Data~1} & \bitbox{16}{Data~2} \\
@@ -817,49 +1450,126 @@
 %           \bitbox{12}{Command} \\
 %         \wordbox{2}{64-bit random number}
 %       \end{bytefield}
-%   \caption{Complex protocol diagram drawn with the \texttt{bytefield}
+%     \end{lrbox}
+%     \makebox[0pt][c]{\usebox{\protocoldiagram}}
+%   \caption{Complex protocol diagram drawn with the \pkgname{bytefield}
 %     package}
 %   \label{fig:complex-diagram}
 % \end{figure}
 %
 %
+% \subsection{Upgrading from older versions}
+% \label{sec:upgrading}
+%
+% \pkgname{bytefield}'s user interface changed substantially with the
+% introduction of version~2.0.  Because documents written for
+% \pkgname{bytefield}~v1.\textit{x} will not build properly under later
+% versions of the package, this section shows how to convert documents
+% to the new interface.
+%
+% \begin{decl}
+%   \SpecialUsageIndex{\wordgroupr}
+%   |\wordgroupr| \\
+%   \SpecialUsageIndex{\endwordgroupr}
+%   |\endwordgroupr|
+% \end{decl}
+%
+% These have been replaced with the |rightwordgroup| environment to make
+% their invocation more \LaTeX-like.  Use |\begin{rightwordgroup}|
+% instead of |\wordgroupr| and |\end{rightwordgroup}| instead of
+% |\endwordgroupr|.
+%
+% \begin{decl}
+%   \SpecialUsageIndex{\wordgroupl}
+%   |\wordgroupl| \\
+%   \SpecialUsageIndex{\endwordgroupl}
+%   |\endwordgroupl|
+% \end{decl}
+%
+% These have been replaced with the |leftwordgroup| environment to make
+% their invocation more \LaTeX-like.  Use |\begin{leftwordgroup}|
+% instead of |\wordgroupl| and |\end{leftwordgroup}| instead of
+% |\endwordgroupl|.
+%
+% \begin{decl}
+%   \SpecialUsageIndex{\bitwidth}
+%   |\bitwidth|
+% \end{decl}
+%
+% Instead of changing bit widths with
+% |\setlength{\bitwidth}{|\meta{width}|}|, use
+% |\bytefieldsetup{bitwidth=|\meta{width}|}|.
+%
+% \begin{decl}
+%   \SpecialUsageIndex{\byteheight}
+%   |\byteheight|
+% \end{decl}
+%
+% Instead of changing bit heights with
+% |\setlength{\byteheight}{|\meta{height}|}|, use
+% |\bytefieldsetup{bitheight=|\meta{height}|}| (and note the change from
+% ``|byte|'' to ``|bit|'' for consistency with \optname{bitwidth}).
+%
+% \begin{decl}
+%   \SpecialUsageIndex{\curlyspace}
+%   |\curlyspace| \\
+%   \SpecialUsageIndex{\labelspace}
+%   |\labelspace|
+% \end{decl}
+%
+% Instead of using |\setlength{\curlyspace}{|\meta{dist}|}| and
+% |\setlength{\labelspace}{|\meta{dist}|}| to alter the horizontal space
+% that appears before and after a curly brace, use
+% |\bytefieldsetup{curlyspace=|\meta{dist}|}| and
+% |\bytefieldsetup{labelspace=|\meta{dist}|}|.  Note that, as described
+% in Section~\ref{sec:basic-cmds}, left and right spacing can be set
+% independently if desired.
+%
+% \begin{decl}
+%   \SpecialUsageIndex{\curlyshrinkage}
+%   |\curlyshrinkage|
+% \end{decl}
+%
+% Instead of using |\setlength{\curlyshrinkage}{|\meta{dist}|}| to
+% reduce the vertical space occupied by a curly brace, use
+% |\bytefieldsetup{curlyshrinkage=|\meta{dist}|}|.  Note that, as
+% described in Section~\ref{sec:basic-cmds}, left and right curly-brace
+% height can be reduced independently if desired.
+%
+% \bigskip
+%
+% As a crutch to help build older documents with minimal modification,
+% \pkgname{bytefield} provides a |compat1| package option that restores
+% the old interface.  This option, invoked with
+% |\usepackage[compat1]{bytefield}|, may disappear in a future version
+% of the package and should therefore not be relied upon as a long-term
+% approach to using \pkgname{bytefield}.
+%
+%
 % \StopEventually{^^A
 %
 %   \section{Future work}
 %
-%   \texttt{bytefield} is my first \LaTeX{} package, and, as such, there
-%   are a number of macros that could probably have been implemented a lot
-%   better.  The package should really get a major rewrite.  If I were to
-%   do it all over again, I would probably not use an \cseq\ialign\ for the
-%   main \texttt{bytefield} environment.  The problem---as I discovered
-%   too late---is that \cseq\begin\ellipsis\cseq\end\ blocks are unable to
-%   cross cells of an \cseq\ialign\ (or \texttt{tabular} environment, for
-%   that matter).
-%
-%   That said, I'd like the next major release of \texttt{bytefield} to
-%   let the user use \texttt{\cseq\begin\char'173
-%   wordgroup\char'175[r]}\ellipsis \texttt{\cseq\end\char'173
-%   wordgroup\char'175} instead of
-%   \cseq\wordgroupr\ellipsis\cseq\endwordgroupr\ and
-%   \texttt{\cseq\begin\char'173 wordgroup\char'175[l]}\ellipsis
-%   \texttt{\cseq\end\char'173 wordgroup\char'175} instead of
-%   \cseq\wordgroupl\ellipsis\cseq\endwordgroupl.  That would make the
-%   word-grouping commands a little more \LaTeX-ish.
-%
-%   Finally, a minor improvement I'd like to make in the package is to
-%   move left, small curly braces closer to the figure.  In the following
-%   figure, notice how distant the small curly appears from the figure
-%   body:
+%   \pkgname{bytefield} is my first \LaTeX\ package, and, as such, there
+%   are a number of macros that could probably have been implemented a
+%   lot better.  For example, \pkgname{bytefield} is somewhat wasteful
+%   of \meta{dimen} registers (although it did get a lot better with
+%   version~1.1 and again with version~1.3).  The package should really
+%   get a major overhaul now that I've gotten better at \TeX\slash
+%   \LaTeX\ programming.  One minor improvement I'd like to make in the
+%   package is to move left, small curly braces closer to the bit field.
+%   In the following figure, notice how distant the small curly appears
+%   from the bit-field body:
 %
 %   \begin{bffigure}
-%         \setlength{\byteheight}{4ex}
+%         \bytefieldsetup{bitheight=4ex}
 %         \begin{bytefield}{16}
-%           \wordgroupl{Too distant}
+%           \begin{leftwordgroup}{Too distant}
 %             \wordbox{1}{Something}
-%           \endwordgroupl \\
-%           \wordgroupl{Looks okay}
+%           \end{leftwordgroup} \\
+%           \begin{leftwordgroup}{Looks okay}
 %             \wordbox{4}{Something else}
-%           \endwordgroupl
+%           \end{leftwordgroup}
 %         \end{bytefield}
 %   \end{bffigure}
 %
@@ -873,19 +1583,15 @@
 %
 % \newcommand{\usermacro}{\marginpar{\vspace*{1ex}{\hspace{18pt}\huge$\star$}\vspace*{-1ex}}}
 %
-% This section contains the complete source code for \texttt{bytefield}.
+% This section contains the complete source code for \pkgname{bytefield}.
 % Most users will not get much out of it, but it should be of use to
 % those who need more precise documentation and those who want to extend
-% (or debug~\smileyface) the \texttt{bytefield} package.
-%
-% In this section, macros marked in the margin with a ``{\Large $\star$}''
-% are intended to be called by the user (and were described in the previous
-% section).  All other macros are used only internally by \texttt{bytefield}.
-%
-%    \begin{macrocode}
-%<*package>
-%    \end{macrocode}
+% (or debug~\smiley) the \pkgname{bytefield} package.
 %
+% In this section, macros marked in the margin with a ``{\Large
+%   $\star$}'' are intended to be called by the user (and were described
+% in Section~\ref{sec:usage}).  All other macros are used only
+% internally by \pkgname{bytefield}.
 %
 % \subsection{Required packages}
 %
@@ -896,11 +1602,12 @@
 % version of |calc.sty| we explicitly specify a later date when loading
 % the |calc| package.
 % \changes{v1.2a}{2005/07/31}{Specified an explicit package date when
-%   loading the \texttt{calc} package to avoid loading an outdated
+%   loading the \pkgname{calc} package to avoid loading an outdated
 %   version.  Thanks to Kevin Quick for discovering that outdated versions
-%   of \texttt{calc} are still being included in \TeX{} distributions.}
+%   of \pkgname{calc} are still being included in \TeX{} distributions.}
 %    \begin{macrocode}
 \RequirePackage{calc}[1998/07/07]
+\RequirePackage{keyval}
 %    \end{macrocode}
 %
 %
@@ -910,25 +1617,31 @@
 % and the ``skipped words''-drawing macros.
 %
 % \begin{macro}{\bf@newdimen}
-% \changes{v1.1}{2002/09/15}{Bug fix: Added
-%   \texttt{\string\string\string\bf@newdimen} to eliminate ``\texttt{No
-%   room for a new \string\string\string\dimen}'' errors (reported by
-%   Vitaly A. Repin)}
+% \begin{macro}{\allocationnumber}
+% \changes{v1.1}{2002/09/15}{Bug fix: Added \cs{bf@newdimen} to greatly
+%   reduce the likelihood of ``\texttt{No room for a new \cs{dimen}}''
+%   errors (reported by Vitaly A. Repin)}
 % |\newdimen| defines new \meta{dimen}s globally.  |\bf@newdimen|
 % defines them locally.  It simply merges \LaTeXe's |\newdimen| and
 % |\alloc@| macros while omitting |\alloc@|'s ``|\global|'' declaration.
 %    \begin{macrocode}
 \def\bf@newdimen#1{\advance\count11 by 1
-  \ch@ck1\insc@unt\dimen% Check room
+  \ch@ck1\insc@unt\dimen
   \allocationnumber=\count11
   \dimendef#1=\allocationnumber
-  \wlog{\string#1=\string\dimen\the\allocationnumber\space (locally)}}
+  \wlog{\string#1=\string\dimen\the\allocationnumber\space (locally)}%
+}
 %    \end{macrocode}
-% If we're using $\varepsilon$-\TeX, we have access to many more
-% \meta{dimen}s.  The \textsf{etex} package makes these available via
-% the |\locdimen| macro.  At the start of the document we check if
-% |\locdimen| is defined and, if so, replace the preceding definition of
-% |\bf@newdimen| with \textsf{etex}'s |\locdimen|.
+% \end{macro}
+% \end{macro}
+%
+% \begin{macro}{\bf@newdimen}
+% If we're using $\varepsilon$-\TeX\ then we have access to many more
+% \meta{dimen}s than in original \TeX\@.  The \textsf{etex} package
+% makes these extra \meta{dimen}s available via the |\locdimen| macro.
+% At the start of the document we check if |\locdimen| is defined and,
+% if so, replace the preceding definition of |\bf@newdimen| with
+% \textsf{etex}'s |\locdimen|.
 % \changes{v1.3}{2010/10/31}{Added support for $\varepsilon$-\TeX's larger
 %   local \meta{dimen} pool (code provided by Heiko Oberdiek)}
 %    \begin{macrocode}
@@ -958,9 +1671,9 @@
 %
 % \begin{macro}{\inc@bytefield@height}
 % We have to define a special macro to increment |\bytefield@height|
-% because the \texttt{calc} package's |\addtolength| macro doesn't seem
+% because the \pkgname{calc} package's |\addtolength| macro doesn't seem
 % to see the global value.  So we |\setlength| a temporary (to get
-% \texttt{calc}'s nice infix features) and |\advance| |\bytefield@height|
+% \pkgname{calc}'s nice infix features) and |\advance| |\bytefield@height|
 % by that amount.
 %    \begin{macrocode}
 \newlength{\bytefield@height@increment}
@@ -983,7 +1696,7 @@
 % \begin{macro}{\entire@bytefield@picture}
 % A box containing the entire bytefield.  By storing everything in a box
 % and then typesetting it later (at the |\end{bytefield}|), we can center
-% the bytefield, put a box around it, and do other operations on the entire
+% the bit field, put a box around it, and do other operations on the entire
 % figure.
 %    \begin{macrocode}
 \newsavebox{\entire@bytefield@picture}
@@ -992,38 +1705,44 @@
 %
 % \begin{environment}{bytefield}
 % \usermacro
+% \begin{macro}{\old@nl}
+% \begin{macro}{\amp}
 % Environment containing the layout of bits in a sequence of bytes.
-% This is the main environment defined by the \texttt{bytefield} pacakge.
+% This is the main environment defined by the \pkgname{bytefield} package.
 % The argument is the number of bits wide the bytefield should be.
 % We turn |&| into a space character so the user can think of a
-% \texttt{bytefield} as being analogous to a \texttt{tabular} environment,
+% \pkgname{bytefield} as being analogous to a \texttt{tabular} environment,
 % even though we're really setting the bulk of the picture in a single
 % column.  (Row labels go in separate columns, however.)
 %    \begin{macrocode}
-\newenvironment{bytefield}[1]{%
-  \setcounter{bits@wide}{#1}%
+\newenvironment{bytefield}[2][]{%
+  \bf@bytefieldsetup{#1}%
+  \setcounter{bits@wide}{#2}%
   \let\old@nl=\\%
   \let\amp=&%
   \catcode`\&=10
   \openup -1pt
   \setlength{\bytefield@height}{0pt}%
   \setlength{\unitlength}{1pt}%
-  \counting@wordstrue
+  \global\counting@wordstrue
   \begin{lrbox}{\entire@bytefield@picture}%
 %    \end{macrocode}
+% \end{macro}
+% \end{macro}
 % \begin{macro}{\\}
 % We redefine |\\| within the |bytefield| environment to make it aware
 % of curly braces that surround the protocol diagram.
 %    \begin{macrocode}
   \renewcommand{\\}{%
-    \amp\show@wordlabelr\cr%
-    \ignorespaces\counting@wordstrue\make@lspace\amp}%
+    \unskip
+    \amp\show@wordlabelr\cr
+    \ignorespaces\global\counting@wordstrue\make@lspace\amp}%
 %    \end{macrocode}
 % \end{macro}
 %    \begin{macrocode}
-  \vbox\bgroup\ialign\bgroup##\amp##\amp##\cr\amp%
+  \vbox\bgroup\ialign\bgroup##\amp##\amp##\cr\amp
 }{%
-  \amp\show@wordlabelr\cr\egroup\egroup%
+  \amp\show@wordlabelr\cr\egroup\egroup
   \end{lrbox}%
   \usebox{\entire@bytefield@picture}}
 %    \end{macrocode}
@@ -1033,23 +1752,44 @@
 %
 % \subsubsection{Drawing (proper)}
 %
-% \begin{macro}{\bitwidth}
-% \usermacro
+% \begin{macro}{\bf@bitformatting}
+% Formats a bit number in the bit header.  |\bf@bitformatting| may be
+% redefined to take either a single argument (\`a~la |\textbf|) or no
+% argument (\`a~la |\small|).
+% \changes{v1.4}{2011/01/15}{Introduced this macro at Steven R. King's
+%   request to enable users to alter the bit header's font size}
+%    \begin{macrocode}
+\newcommand*{\bf@bitformatting}{\tiny}
+%    \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\bf@boxformatting}
+% Formats the text within a bit box or word box.  |\bf@boxformatting|
+% takes either a single argument (\`a~la |\textbf|) or no argument
+% (\`a~la |\small|).  The text that follows |\bf@boxformatting| is
+% guaranteed to be a group that ends in |\par|, so if
+% |\bf@boxformatting| accepts an argument, the macro should be defined
+% with |\long| (e.g.,~with |\newcommand| but not with |\newcommand*|).
+%    \begin{macrocode}
+\newcommand*{\bf@boxformatting}{\centering}
+%    \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\bf@bitwidth}
 % The width of a single bit.  Note that this is wide enough to display a
 % two-digit number without it running into adjacent numbers.  For larger
 % words, be sure to |\setlength| this larger.
 %    \begin{macrocode}
-\newlength{\bitwidth}
-\AtBeginDocument{\settowidth{\bitwidth}{\tiny 99i}}
+\newlength{\bf@bitwidth}
+\settowidth{\bf@bitwidth}{\bf@bitformatting{99i}}
 %    \end{macrocode}
 % \end{macro}
 %
-% \begin{macro}{\byteheight}
-% \usermacro
-% The height of a single byte.
+% \begin{macro}{\bf@bitheight}
+% The height of a single bit within the bit field.
 %    \begin{macrocode}
-\newlength{\byteheight}
-\AtBeginDocument{\setlength{\byteheight}{4ex}}
+\newlength{\bf@bitheight}
+\setlength{\bf@bitheight}{4ex}
 %    \end{macrocode}
 % \end{macro}
 %
@@ -1072,9 +1812,9 @@
 % |[r]|ight, |[t]|op, and/or |[b]|ottom (default: |lrtb|).
 %    \begin{macrocode}
 \DeclareRobustCommand{\bitbox}[3][lrtb]{%
-  \setlength{\units@wide}{\bitwidth * #2}%
+  \setlength{\units@wide}{\bf@bitwidth * #2}%
   \parse@bitbox@arg{#1}%
-  \draw@bit@picture{\strip@pt\units@wide}{\strip@pt\byteheight}{#3}}
+  \draw@bit@picture{\strip@pt\units@wide}{\strip@pt\bf@bitheight}{#3}}
 %    \end{macrocode}
 % \end{macro}
 %
@@ -1086,8 +1826,8 @@
 % |[r]|ight, |[t]|op, and/or |[b]|ottom (default: |lrtb|).
 %    \begin{macrocode}
 \DeclareRobustCommand{\wordbox}[3][lrtb]{%
-  \setlength{\units@wide}{\bitwidth * \value{bits@wide}}%
-  \setlength{\units@tall}{\byteheight * #2}%
+  \setlength{\units@wide}{\bf@bitwidth * \value{bits@wide}}%
+  \setlength{\units@tall}{\bf@bitheight * #2}%
   \parse@bitbox@arg{#1}%
   \draw@bit@picture{\strip@pt\units@wide}{\strip@pt\units@tall}{#3}}
 %    \end{macrocode}
@@ -1116,7 +1856,7 @@
 %   First, we plot the user's text, with all sorts of useful lengths
 %   predefined.
 %    \begin{macrocode}
-    \put(0,0){\makebox(#1,#2){\parbox[c]{#1\unitlength}{%
+    \put(0,0){\makebox(#1,#2){\parbox{#1\unitlength}{%
       \bf@newdimen\height
       \bf@newdimen\depth
       \bf@newdimen\totalheight
@@ -1127,7 +1867,7 @@
       \width=#1\unitlength
       \def\widthunits{#1}%
       \def\heightunits{#2}%
-      \centering #3}}}%
+      \bf@boxformatting{#3\par}}}}%
 %    \end{macrocode}
 % \end{macro}
 % \end{macro}
@@ -1160,7 +1900,7 @@
 %    \begin{macrocode}
   \ifcounting@words
     \inc@bytefield@height{\unitlength * \real{#2}}%
-    \counting@wordsfalse
+    \global\counting@wordsfalse
   \fi
   \ignorespaces}
 %    \end{macrocode}
@@ -1247,7 +1987,7 @@
 % is the vertical space between the two diagonal lines (default: |2ex|).
 %    \begin{macrocode}
 \DeclareRobustCommand{\skippedwords}[1][2ex]{%
-  \setlength{\units@wide}{\bitwidth * \value{bits@wide}}%
+  \setlength{\units@wide}{\bf@bitwidth * \value{bits@wide}}%
   \setlength{\units@high}{1pt * \ratio{\units@wide}{6.0pt}}%
   \setlength{\units@tall}{#1 + \units@high}%
   \edef\num@wide{\strip@pt\units@wide}%
@@ -1261,7 +2001,7 @@
   \end{picture}%
   \ifcounting@words
     \inc@bytefield@height{\unitlength * \real{\num@tall}}%
-    \counting@wordsfalse
+    \global\counting@wordsfalse
   \fi}
 %    \end{macrocode}
 % \end{macro}
@@ -1280,8 +2020,8 @@
 %    \begin{macrocode}
 \DeclareRobustCommand{\bitheader}[2][l]{%
   \parse@bitbox@arg{lrtb}%
-  \setlength{\units@wide}{\bitwidth * \value{bits@wide}}%
-  \setlength{\units@tall}{\heightof{\tiny 9}}%
+  \setlength{\units@wide}{\bf@bitwidth * \value{bits@wide}}%
+  \setlength{\units@tall}{\heightof{\bf@bitformatting{1234567890}}}%
   \setlength{\units@high}{\units@tall * -1}%
   \def\bit@endianness{#1}%
   \begin{picture}(\strip@pt\units@wide,\strip@pt\units@tall)%
@@ -1290,7 +2030,7 @@
   \end{picture}%
   \ifcounting@words
     \inc@bytefield@height{\unitlength * \real{\strip@pt\units@tall}}%
-    \counting@wordsfalse
+    \global\counting@wordsfalse
   \fi
   \ignorespaces}
 %    \end{macrocode}
@@ -1338,13 +2078,13 @@
     \ifnum\value{header@val}<\value{max@header@val}%
       \if\bit@endianness b%
         \setlength{\header@xpos}{%
-          \bitwidth * (\value{bits@wide}-\value{header@val}-1)}
+          \bf@bitwidth * (\value{bits@wide}-\value{header@val}-1)}
       \else
-        \setlength{\header@xpos}{\bitwidth * \value{header@val}}
+        \setlength{\header@xpos}{\bf@bitwidth * \value{header@val}}
       \fi
       \put(\strip@pt\header@xpos,0){%
-        \makebox(\strip@pt\bitwidth,\strip@pt\units@tall){%
-          \tiny \theheader@val}}
+        \makebox(\strip@pt\bf@bitwidth,\strip@pt\units@tall){%
+          \bf@bitformatting{\theheader@val}}}
       \addtocounter{header@val}{1}
   \repeat}
 %    \end{macrocode}
@@ -1354,41 +2094,61 @@
 %
 % \subsubsection{Curly-brace manipulation}
 %
-% \begin{macro}{\curlyshrinkage}
-% \usermacro
-% Reduce the height of a curly brace by |\curlyshrinkage| so its ends don't
+% \begin{macro}{\bf@leftcurlyshrinkage}
+% \begin{macro}{\bf@rightcurlyshrinkage}
+% Reduce the height of a left (right) curly brace by
+% |\bf@leftcurlyshrinkage| (|\bf@rightcurlyshrinkage|) so its ends don't
 % overlap whatever is above or below it.  The default value (5\,pt.) was
-% determined empirically and shouldn't need to be changed.  However,
-% on the off-chance the user employs a math font with very different
-% curly braces from Computer Modern's, |\curlyshrinkage| can be modified.
+% determined empirically and shouldn't need to be changed.  However, on
+% the off-chance the user employs a math font with very different curly
+% braces from Computer Modern's, |\bf@leftcurlyshrinkage| and
+% |\bf@rightcurlyshrinkage| can be modified.
 %    \begin{macrocode}
-\newlength{\curlyshrinkage}
-\setlength{\curlyshrinkage}{5pt}
+\def\bf@leftcurlyshrinkage{5pt}
+\def\bf@rightcurlyshrinkage{5pt}
 %    \end{macrocode}
 % \end{macro}
+% \end{macro}
 %
-% \begin{macro}{\curlyspace}
-% \usermacro
-% \begin{macro}{\labelspace}
-% \usermacro
+% \begin{macro}{\bf@leftcurlyspace}
+% \begin{macro}{\bf@rightcurlyspace}
+% \begin{macro}{\bf@leftlabelspace}
+% \begin{macro}{\bf@rightlabelspace}
 % Space to insert before a curly brace and before a word label
-% (i.e., after a curly brace).  Because the default values are specified
-% in terms of $x$~heights, we wait until the |\begin{document}| to set
-% them, after the default font has been selected.
+% (i.e.,~after a curly brace).
+%    \begin{macrocode}
+\def\bf@leftcurlyspace{0pt}
+\def\bf@rightcurlyspace{0pt}
+\def\bf@leftlabelspace{0pt}
+\def\bf@rightlabelspace{0pt}
+%    \end{macrocode}
+%    \begin{macrocode}
+\gdef\bf@leftcurlyspace{1ex}
+\gdef\bf@rightcurlyspace{1ex}
+\gdef\bf@leftlabelspace{0.5ex}
+\gdef\bf@rightlabelspace{0.5ex}
+%    \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \begin{macro}{\bf@leftcurly}
+% \begin{macro}{\bf@rightcurly}
+% Symbols to use as left and right curly braces.  These symbols must be
+% extensible math symbols (i.e.,~they will immediately follow |\left| or
+% |\right| in math mode).
 %    \begin{macrocode}
-\newlength{\curlyspace}
-\AtBeginDocument{\setlength{\curlyspace}{1ex}}
-\newlength{\labelspace}
-\AtBeginDocument{\setlength{\labelspace}{0.5ex}}
+\let\bf@leftcurly=\{
+\let\bf@rightcurly=\}
 %    \end{macrocode}
 % \end{macro}
 % \end{macro}
 %
 % \begin{macro}{\curly@box}
 % Define a box in which to temporarily store formatted curly braces.
-% \changes{v1.2}{2004/06/14}{Bug fix: Defined
-%   \texttt{\string\string\string\curly@box} globally (suggested by
-%     Stefan Ulrich)}
+% \changes{v1.2}{2004/06/14}{Bug fix: Defined \cs{curly@box} globally
+%   (suggested by Stefan Ulrich)}
 %    \begin{macrocode}
 \newbox{\curly@box}
 %    \end{macrocode}
@@ -1398,6 +2158,7 @@
 % \begin{macro}{\curly@height}
 % \begin{macro}{\half@curly@height}
 % \begin{macro}{\curly@shift}
+% \begin{macro}{\old@axis}
 % Store a ``\}'' that's |#2| tall in box |#1|.
 % The only unintuitive thing here is that we have to redefine
 % |\fontdimen22|---axis height---to~0\,pt.\ before typesetting the curly
@@ -1406,18 +2167,20 @@
 %    \begin{macrocode}
 \def\store@rcurly#1#2{%
   \begingroup
-    \bf@newdimen\curly@height%
-    \setlength{\curly@height}{#2 - \curlyshrinkage}%
-    \bf@newdimen\half@curly@height%
+    \bf@newdimen\curly@height
+    \setlength{\curly@height}{#2 - \bf@rightcurlyshrinkage}%
+    \bf@newdimen\half@curly@height
     \setlength{\half@curly@height}{0.5\curly@height}%
-    \bf@newdimen\curly@shift%
-    \setlength{\curly@shift}{\half@curly@height + 0.5\curlyshrinkage}%
+    \bf@newdimen\curly@shift
+    \setlength{\curly@shift}{\bf@rightcurlyshrinkage}%
+    \setlength{\curly@shift}{\half@curly@height + 0.5\curly@shift}%
     \global\sbox{#1}{\raisebox{\curly@shift}{%
       $\xdef\old@axis{\the\fontdimen22\textfont2}$%
       $\fontdimen22\textfont2=0pt%
-       \left.\vrule height\half@curly@height
-                    width 0pt
-                    depth\half@curly@height\right\}$%
+       \left.
+       \vrule height\half@curly@height
+              width 0pt
+              depth\half@curly@height\right\bf@rightcurly$%
       $\fontdimen22\textfont2=\old@axis$}}%
   \endgroup
 }
@@ -1426,6 +2189,7 @@
 % \end{macro}
 % \end{macro}
 % \end{macro}
+% \end{macro}
 %
 % \begin{macro}{\store@lcurly}
 % \begin{macro}{\curly@height}
@@ -1435,18 +2199,20 @@
 %    \begin{macrocode}
 \def\store@lcurly#1#2{%
   \begingroup
-    \bf@newdimen\curly@height%
-    \setlength{\curly@height}{#2 - \curlyshrinkage}%
-    \bf@newdimen\half@curly@height%
+    \bf@newdimen\curly@height
+    \setlength{\curly@height}{#2 - \bf@leftcurlyshrinkage}%
+    \bf@newdimen\half@curly@height
     \setlength{\half@curly@height}{0.5\curly@height}%
-    \bf@newdimen\curly@shift%
-    \setlength{\curly@shift}{\half@curly@height + 0.5\curlyshrinkage}%
+    \bf@newdimen\curly@shift
+    \setlength{\curly@shift}{\bf@leftcurlyshrinkage}%
+    \setlength{\curly@shift}{\half@curly@height + 0.5\curly@shift}%
     \global\sbox{#1}{\raisebox{\curly@shift}{%
       $\xdef\old@axis{\the\fontdimen22\textfont2}$%
       $\fontdimen22\textfont2=0pt%
-       \left\{\vrule height\half@curly@height
-                     width 0pt
-                     depth\half@curly@height\right.$%
+       \left\bf@leftcurly
+       \vrule height\half@curly@height
+              width 0pt
+              depth\half@curly@height\right.$%
       $\fontdimen22\textfont2=\old@axis$}}%
   \endgroup
 }
@@ -1461,7 +2227,7 @@
 % \begin{macro}{\show@wordlabelr}
 % This macro is output in the third column of every row of the
 % |\ialign|ed bytefield table.  It's normally a no-op, but
-% |\endwordgroupr| defines it to output the word label and then
+% |\end{rightwordgroup}| defines it to output the word label and then
 % reset itself to a no-op.
 %    \begin{macrocode}
 \def\show@wordlabelr{}
@@ -1479,39 +2245,49 @@
 % \end{macro}
 % \end{macro}
 %
-% \begin{macro}{\wordgroupr}
-% \usermacro
-% \begin{macro}{\endwordgroupr}
+% \begin{environment}{rightwordgroup}
 % \usermacro
-% Label the words defined between |\wordgroupr| and |\endwordgroupr|
-% on the right side of the figure.
+% Label the words defined between |\begin{rightwordgroup}| and |\end{rightwordgroup}|
+% on the right side of the bit field.
 % The argument is the text of the label.  The label is typeset to the
 % right of a large curly brace, which groups the words together.
 %    \begin{macrocode}
-\newenvironment{wordgroupr}[1]{%
+\newenvironment{rightwordgroup}[1]{%
+%    \end{macrocode}
+% We begin by ending the group that |\begin{rightwordgroup}| created.  This
+% lets the |rightwordgroup| environment span rows (because we're technically
+% no longer within the environment).
+%    \begin{macrocode}
+  \endgroup
 %    \end{macrocode}
 % \begin{macro}{\wordlabelr@start}
 % \begin{macro}{\wordlabelr@text}
-% \begin{macro}{\wordlabelr@end}
-% |\wordgroupr| merely stores the starting height in |\wordlabelr@start|
-% and the user-supplied text in |\wordlabelr@text|.  |\endwordgroupr|
+% |\begin{rightwordgroup}| merely stores the starting height in |\wordlabelr@start|
+% and the user-supplied text in |\wordlabelr@text|.  |\end{rightwordgroup}|
 % does most of the work.
 %    \begin{macrocode}
   \global\wordlabelr@start=\bytefield@height
   \gdef\wordlabelr@text{#1}%
-  \ignorespaces%
+  \ignorespaces
 }{%
-  \global\wordlabelr@end=\bytefield@height
 %    \end{macrocode}
 % \end{macro}
 % \end{macro}
+% \begin{macro}{\wordlabelr@end}
+% Because we already ended the group that |\begin{rightwordgroup}| created
+% we now have to begin a group for |\end{rightwordgroup}| to end.
+%    \begin{macrocode}
+  \begingroup
+  \global\wordlabelr@end=\bytefield@height
+%    \end{macrocode}
 % \end{macro}
 % \begin{macro}{\show@wordlabelr}
-% Redefine |\show@wordlabelr| to output |\curlyspace| space, followed by
-% a large curly brace (in |\curlybox|), followed by |\labelspace| space,
-% followed by the user's text (previously recorded in |\wordlabelr@text|).
-% We typeset |\wordlabelr@text| within a |tabular| environment, so
-% \LaTeX\ will calculate its width automatically.
+% Redefine |\show@wordlabelr| to output |\bf@rightcurlyspace| space,
+% followed by a large curly brace (in |\curlybox|), followed by
+% |\bf@rightlabelspace| space, followed by the user's text (previously
+% recorded in |\wordlabelr@text|).  We typeset |\wordlabelr@text| within
+% a |tabular| environment, so \LaTeX\ will calculate its width
+% automatically.
 %    \begin{macrocode}
   \gdef\show@wordlabelr{%
     \sbox{\word@label@box}{%
@@ -1519,17 +2295,17 @@
     \settowidth{\label@box@width}{\usebox{\word@label@box}}%
     \setlength{\label@box@height}{\wordlabelr@end-\wordlabelr@start}%
     \store@rcurly{\curly@box}{\label@box@height}%
-    \bf@newdimen\total@box@width%
+    \bf@newdimen\total@box@width
     \setlength{\total@box@width}{%
-      \curlyspace +
+      \bf@rightcurlyspace +
       \widthof{\usebox{\curly@box}} +
-      \labelspace +
+      \bf@rightlabelspace +
       \label@box@width}%
     \begin{picture}(\strip@pt\total@box@width,0)
       \put(0,0){%
-        \hspace*{\curlyspace}%
+        \hspace*{\bf@rightcurlyspace}%
         \usebox{\curly@box}%
-        \hspace*{\labelspace}%
+        \hspace*{\bf@rightlabelspace}%
         \makebox(\strip@pt\label@box@width,\strip@pt\label@box@height){%
           \usebox{\word@label@box}}}
     \end{picture}%
@@ -1537,11 +2313,20 @@
 % The last thing |\show@wordlabelr| does is redefine itself back to a no-op.
 %    \begin{macrocode}
     \gdef\show@wordlabelr{}}%
-  \ignorespaces}
 %    \end{macrocode}
 % \end{macro}
+% \begin{macro}{\@currenvir}
+%    \begin{macrocode}
+% Because of our meddling with |\begingroup| and |\endgroup|, the
+% current environment is all messed up.  We therefore force the
+% |\end{rightwordgroup}| to succeed, even if it doesn't match the preceding
+% |\begin|.
+  \def\@currenvir{rightwordgroup}%
+  \ignorespaces
+}
+%    \end{macrocode}
 % \end{macro}
-% \end{macro}
+% \end{environment}
 %
 % \subsubsection{Left-side labels}
 %
@@ -1557,7 +2342,7 @@
 % \end{macro}
 %
 % \begin{macro}{\total@box@width}
-% The total width of the next label to typeset on the left of the figure,
+% The total width of the next label to typeset on the left of the bit field,
 % that is, the aggregate width of the text box, curly brace, and spaces
 % on either side of the curly brace.
 %    \begin{macrocode}
@@ -1568,46 +2353,52 @@
 % \begin{macro}{\make@lspace}
 % This macro is output in the first column of every row of the
 % |\ialign|ed bytefield table.  It's normally a no-op, but
-% |\wordgroupl| defines it to output enough space for the next word
+% |\begin{leftwordgroup}| defines it to output enough space for the next word
 % label and then reset itself to a no-op.
 %    \begin{macrocode}
 \gdef\make@lspace{}
 %    \end{macrocode}
 % \end{macro}
 %
-% \begin{macro}{\wordgroupl}
-% \usermacro
-% \begin{macro}{\endwordgroupl}
+% \begin{environment}{leftwordgroup}
 % \usermacro
-% Same as |\wordgroupr| and |\endwordgroupr|, but put the label on the left.
-% However, the following code is not symmetric to that of |\wordgroupr|
-% and |\endwordgroupr|.  The problem is that we encounter |\wordgroupl|
-% after entering the second (i.e., figure) column, which doesn't give us
-% a chance to reserve space in the first (i.e., left label) column.
-% When we reach the |\endwordgroupl|, we know the height of the group of
-% words we wish to label.  However, if we try to label the words in the
-% subsequent first column, we won't know the vertical offset from the
-% ``cursor'' at which to start drawing the label, because we can't know
-% the height of the subsequent row until we reach the second
+% This environment is essentially the same as the |rightwordgroup|
+% environment but puts the label on the left.  However, the following
+% code is not symmetric to that of |rightwordgroup|.  The problem is that we
+% encounter |\begin{leftwordgroup}| after entering the second
+% (i.e.,~figure) column, which doesn't give us a chance to reserve space
+% in the first (i.e.,~left label) column.  When we reach the
+% |\end{leftwordgroup}|, we know the height of the group of words we wish
+% to label.  However, if we try to label the words in the subsequent
+% first column, we won't know the vertical offset from the ``cursor'' at
+% which to start drawing the label, because we can't know the height of
+% the subsequent row until we reach the second
 % column.\footnote{Question: Is there a way to push the label up to the
-% \emph{top} of the subsequent row, perhaps with
-% \texttt{\textbackslash vfill}?}
+%   \emph{top} of the subsequent row, perhaps with
+%   \texttt{\string\vfill}?}
 %
 % Our solution is to allocate space for the box the next time we enter a
 % first column.  As long as space is eventually allocated, the column
-% will expand to fit that space.  |\endwordgroupl| outputs the label
-% immediately.  Even though |\endwordgroupl| is called at the end
-% of the \emph{second} column, it |\put|s the label at a sufficiently
-% negative $x$ location for it to overlap the first column.  Because there
-% will eventually be enough space to accomodate the label, we know that
-% the label won't overlap the figure or extend beyond the figure boundaries.
+% will expand to fit that space.  |\end{leftwordgroup}| outputs the label
+% immediately.  Even though |\end{leftwordgroup}| is called at the end of
+% the \emph{second} column, it |\put|s the label at a sufficiently
+% negative $x$ location for it to overlap the first column.  Because
+% there will eventually be enough space to accomodate the label, we know
+% that the label won't overlap the bit field or extend beyond the bit-field
+% boundaries.
 %    \begin{macrocode}
-\newenvironment{wordgroupl}[1]{%
+\newenvironment{leftwordgroup}[1]{%
+%    \end{macrocode}
+% We begin by ending the group that |\begin{rightwordgroup}| created.  This
+% lets the |leftwordgroup| environment span rows (because we're technically
+% no longer within the environment).
+%    \begin{macrocode}
+  \endgroup
 %    \end{macrocode}
 % \begin{macro}{\wordlabell@start}
 % \begin{macro}{\wordlabell@text}
-% First, we store the starting height and label text, which are needed
-% by |\endwordgroupl|.
+% We store the starting height and label text, which are needed by the
+% |\end{leftwordgroup}|.
 %    \begin{macrocode}
   \global\wordlabell@start=\bytefield@height
   \gdef\wordlabell@text{#1}%
@@ -1617,7 +2408,7 @@
 % Next, we typeset a draft version of the label into |\word@label@box|,
 % which we measure (into |\total@lbox@width|) and then discard.
 % We can't typeset the final version of the label until we reach the
-% |\endwordgroupl|, because that's when we learn the height of the
+% |\end{leftwordgroup}|, because that's when we learn the height of the
 % word group.  Without knowing the height of the word group, we don't
 % how how big to make the curly brace.  In the scratch version, we make
 % the curly brace 5\,cm.~tall.  This should be more than large enough to
@@ -1629,12 +2420,13 @@
   \settowidth{\label@box@width}{\usebox{\word@label@box}}%
   \store@lcurly{\curly@box}{5cm}%
   \setlength{\total@lbox@width}{%
-    \curlyspace +
+    \bf@leftcurlyspace +
     \widthof{\usebox{\curly@box}} +
-    \labelspace +
+    \bf@leftlabelspace +
     \label@box@width}%
   \global\total@lbox@width=\total@lbox@width
 %    \end{macrocode}
+% \begin{macro}{\make@lspace}
 % Now we know how wide the box is going to be (unless, of course,
 % the user is using some weird math font that scales the width of a curly
 % brace proportionally to its height).  So we redefine |\make@lspace| to
@@ -1644,22 +2436,29 @@
   \gdef\make@lspace{%
     \hspace*{\total@lbox@width}%
     \gdef\make@lspace{}}%
-  \ignorespaces%
+  \ignorespaces
 }{%
 %    \end{macrocode}
-% |\endwordgroupl| is comparatively straightforward.  We calculate the
-% final height of the word group, and then output the label text, followed
-% by |\labelspace| space, followed by a curly brace (now that we know how
-% tall it's supposed to be), followed by |\curlyspace| space.  The trick,
-% as described earlier, is that we typeset the entire label in the second
-% column, but in a $0 \times 0$ |picture| environment and with a negative
-% horizontal offset (|\starting@point|), thereby making it overlap the
-% first column.
+% \end{macro}
+% Because we already ended the group that |\begin{leftwordgroup}| created
+% we have to start the |\end{leftwordgroup}| by beginning a group for
+% |\end{leftwordgroup}| to end.
+%    \begin{macrocode}
+  \begingroup
+%    \end{macrocode}
+% The |\end{leftwordgroup}| code is comparatively straightforward.  We
+% calculate the final height of the word group, and then output the
+% label text, followed by |\bf@leftlabelspace| space, followed by a
+% curly brace (now that we know how tall it's supposed to be), followed
+% by |\bf@leftcurlyspace| space.  The trick, as described earlier, is
+% that we typeset the entire label in the second column, but in a $0
+% \times 0$ |picture| environment and with a negative horizontal offset
+% (|\starting@point|), thereby making it overlap the first column.
 %    \begin{macrocode}
   \global\wordlabell@end=\bytefield@height
   \bf@newdimen\starting@point
   \setlength{\starting@point}{%
-    -\total@lbox@width - \bitwidth*\value{bits@wide}}%
+    -\total@lbox@width - \bf@bitwidth*\value{bits@wide}}%
   \sbox{\word@label@box}{%
     \begin{tabular}[b]{@{}l@{}}\wordlabell@text\end{tabular}}%
   \settowidth{\label@box@width}{\usebox{\word@label@box}}%
@@ -1669,14 +2468,22 @@
     \put(\strip@pt\starting@point,0){%
       \makebox(\strip@pt\label@box@width,\strip@pt\label@box@height){%
         \usebox{\word@label@box}}%
-      \hspace*{\labelspace}%
+      \hspace*{\bf@leftlabelspace}%
       \usebox{\curly@box}%
-      \hspace*{\curlyspace}}
+      \hspace*{\bf@leftcurlyspace}}
   \end{picture}%
+%    \end{macrocode}
+% \begin{macro}{\@currenvir}
+%    \begin{macrocode}
+% Because of our meddling with |\begingroup| and |\endgroup|, the
+% current environment is all messed up.  We therefore force the
+% |\end{leftwordgroup}| to succeed, even if it doesn't match the preceding
+% |\begin|.
+  \def\@currenvir{leftwordgroup}%
   \ignorespaces}
 %    \end{macrocode}
 % \end{macro}
-% \end{macro}
+% \end{environment}
 %
 % \subsubsection{Scratch space}
 %
@@ -1694,9 +2501,315 @@
 % \end{macro}
 % \end{macro}
 %
+% \subsection{Compatibility mode}
+%
+% \begin{macro}{\bf@enter@compatibility@mode@i}
+% \pkgname{bytefield}'s interface changed substantially with the move to
+% version~2.0.  To give version~1.\textit{x} users a quick way to build
+% their old documents, we provide a version~1.\textit{x} compatibility
+% mode.  We don't enable this by default because it exposes a number of
+% extra length registers (a precious resource) and we therefore want to
+% encourage users to migrate to the new interface.
 %    \begin{macrocode}
-%</package>
+\newcommand{\bf@enter@compatibility@mode@i}{%
 %    \end{macrocode}
+% \begin{macro}{\bitwidth}
+% \begin{macro}{\byteheight}
+% \begin{macro}{\curlyspace}
+% \begin{macro}{\labelspace}
+% \begin{macro}{\curlyshrinkage}
+% Define a handful of lengths that the user was allowed to |\setlength|
+% explicitly in \pkgname{bytefield}~1.\textit{x}.
+%    \begin{macrocode}
+  \PackageInfo{bytefield}{Entering version 1 compatibility mode}%
+  \newlength{\bitwidth}%
+  \newlength{\byteheight}%
+  \newlength{\curlyspace}%
+  \newlength{\labelspace}%
+  \newlength{\curlyshrinkage}%
+%    \end{macrocode}
+%    \begin{macrocode}
+  \settowidth{\bitwidth}{\tiny 99i}%
+  \setlength{\byteheight}{4ex}%
+  \setlength{\curlyspace}{1ex}%
+  \setlength{\labelspace}{0.5ex}%
+  \setlength{\curlyshrinkage}{5pt}%
+%    \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \begin{macro}{\newbytefield}
+% \begin{macro}{\endnewbytefield}
+% \begin{environment}{bytefield}
+% Redefine the |bytefield| environment in terms of the existing
+% (new-interface) |bytefield| environment.  The difference is that the
+% redefinition utilizes all of the preceding lengths.
+%    \begin{macrocode}
+  \let\newbytefield=\bytefield
+  \let\endnewbytefield=\endbytefield
+  \renewenvironment{bytefield}[1]{%
+    \begin{newbytefield}[%
+      bitwidth=\bitwidth,
+      bitheight=\byteheight,
+      curlyspace=\curlyspace,
+      labelspace=\labelspace,
+      curlyshrinkage=\curlyshrinkage]{##1}%
+  }{%
+    \end{newbytefield}%
+  }
+%    \end{macrocode}
+% \end{environment}
+% \end{macro}
+% \end{macro}
+% \begin{macro}{\wordgroupr}
+% \begin{macro}{\endwordgroupr}
+% \begin{macro}{\wordgroupl}
+% \begin{macro}{\endwordgroupl}
+% Define |\wordgroupr|, |\endwordgroupr|, |\wordgroupl|, and
+% |\endwordgroupl| in terms of the new |rightwordgroup| and
+% |leftwordgroup| environments.
+%    \begin{macrocode}
+  \def\wordgroupr{\begin{rightwordgroup}}
+  \def\endwordgroupr{\end{rightwordgroup}}
+  \def\wordgroupl{\begin{leftwordgroup}}
+  \def\endwordgroupl{\end{leftwordgroup}}
+%    \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \begin{macro}{\bytefieldsetup}
+% Disable |\bytefieldsetup| in compatibility mode because it doesn't
+% work as expected.  (Every use of the compatibility-mode |bytefield|
+% environment overwrites all of the figure-formatting values.)
+%    \begin{macrocode}
+  \renewcommand{\bytefieldsetup}[1]{%
+    \PackageError{bytefield}{%
+      The \protect\bytefieldsetup\space macro is not available in\MessageBreak
+      version 1 compatibility mode%
+    }{%
+      Remove [compat1] from the \protect\usepackage{bytefield} line to
+      make \protect\bytefieldsetup\MessageBreak
+      available to this document.\space\space (The document may also need
+      to be modified to use\MessageBreak
+      the new bytefield interface.)
+    }%
+  }%
+}
+%    \end{macrocode}
+% \end{macro}
+% \end{macro}
+%
+% \begin{macro}{\wordgroupr}
+% \begin{macro}{\endwordgroupr}
+% \begin{macro}{\wordgroupl}
+% \begin{macro}{\endwordgroupl}
+% Issue a helpful error message for the commands that were removed in
+% \pkgname{bytefield}~v2.0.  While this won't help users who first
+% invalid action is to modify a no-longer-extant length register such as
+% |\bitwidth| or |\byteheight|, it may benefit at least a few users who
+% didn't realize that the \pkgname{bytefield} interface has changed
+% substantially with version~2.0.
+%    \begin{macrocode}
+\newcommand{\wordgroupr}{%
+  \PackageError{bytefield}{%
+    Macros \protect\wordgroupr, \protect\wordgroupl, \protect\endwordgroupr,
+    \MessageBreak
+    and \protect\endwordgroupl\space no longer exist%
+  }{%
+    Starting with version 2.0, bytefield uses \protect\begin{wordgroupr}...
+    \MessageBreak
+    \protect\end{wordgroupr} and \protect\begin{wordgroupl}...%
+    \protect\end{wordgroupl}\MessageBreak
+    to specify word groups and a new \protect\bytefieldsetup\space macro to
+    \MessageBreak
+    change bytefield's various formatting parameters.%
+  }%
+}
+\let\endwordgroupr=\wordgroupr
+\let\wordgroupl=\wordgroupr
+\let\endwordgroupl=\wordgroupr
+%    \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+%
+% \subsection{Option processing}
+%
+% We use the \textsf{keyval} package to handle option processing.
+% Because all of \pkgname{bytefield}'s options have local impact, options
+% can be specified either as package arguments or through the use of the
+% |\bytefieldsetup| macro.
+%
+% \begin{macro}{\KV@bytefield@bitwidth}
+% \begin{macro}{\bf@bw@arg}
+% \begin{macro}{\bf@auto}
+% Specify the width of a bit number in the bit header.  If the special
+% value ``|auto|'' is given, set the width to the width of a formatted
+% ``|99i|''.
+%    \begin{macrocode}
+\define@key{bytefield}{bitwidth}{%
+  \def\bf@bw@arg{#1}%
+  \def\bf@auto{auto}%
+  \ifx\bf@bw@arg\bf@auto
+    \settowidth{\bf@bitwidth}{\bf@bitformatting{99i}}%
+  \else
+    \setlength{\bf@bitwidth}{#1}%
+  \fi
+}
+%    \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \begin{macro}{\KV@bytefield@bf@bitheight}
+% Specify the height of a bit in a |\bitbox| or |\wordbox|.
+%    \begin{macrocode}
+\define@key{bytefield}{bitheight}{\setlength{\bf@bitheight}{#1}}
+%    \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\KV@bytefield@bitformatting}
+% Specify the style of a bit number in the bit header.  This should be
+% passed an expression that takes either one argument (e.g.,~|\textit|)
+% or no arguments (e.g.,~|{\small\bfseries}|).
+%    \begin{macrocode}
+\define@key{bytefield}{bitformatting}{\def\bf@bitformatting{#1}}
+%    \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\KV@bytefield@boxformatting}
+% Specify a style to be applied to the contents of every bit box and
+% word box. This should be passed an expression that takes either one
+% argument (e.g.,~|\textit|) or no arguments
+% (e.g.,~|{\small\bfseries}|).
+%    \begin{macrocode}
+\define@key{bytefield}{boxformatting}{\def\bf@boxformatting{#1}}
+%    \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\KV@bytefield@leftcurly}
+% \begin{macro}{\KV@bytefield@rightcurly}
+% Specify the symbol to use for bracketing a left or right word group.
+% This must be an extensible math delimiter (i.e.,~something that can
+% immediately follow |\left| or |\right| in math mode).
+%    \begin{macrocode}
+\define@key{bytefield}{leftcurly}{\def\bf@leftcurly{#1}}
+\define@key{bytefield}{rightcurly}{\def\bf@rightcurly{#1}}
+%    \end{macrocode}
+% \end{macro}
+% \end{macro}
+%
+% \begin{macro}{\KV@bytefield@leftcurlyspace}
+% \begin{macro}{\KV@bytefield@rightcurlyspace}
+% \begin{macro}{\KV@bytefield@curlyspace}
+% Specify the amount of space between the bit fields in a word group and
+% the adjacent left or right curly brace.  The \optname{curlyspace}
+% option is a shortcut that puts the same space before both left and
+% right curly braces.
+%    \begin{macrocode}
+\define@key{bytefield}{leftcurlyspace}{\def\bf@leftcurlyspace{#1}}
+\define@key{bytefield}{rightcurlyspace}{\def\bf@rightcurlyspace{#1}}
+\define@key{bytefield}{curlyspace}{%
+  \def\bf@leftcurlyspace{#1}%
+  \def\bf@rightcurlyspace{#1}%
+}
+%    \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \begin{macro}{\KV@bytefield@leftlabelspace}
+% \begin{macro}{\KV@bytefield@rightlabelspace}
+% \begin{macro}{\KV@bytefield@labelspace}
+% Specify the amount of space between a left or right word group's curly
+% brace and the associated label text.  The |labelspace| option is a
+% shortcut that puts the same space after both left and right curly
+% braces.
+%    \begin{macrocode}
+\define@key{bytefield}{leftlabelspace}{\def\bf@leftlabelspace{#1}}
+\define@key{bytefield}{rightlabelspace}{\def\bf@rightlabelspace{#1}}
+\define@key{bytefield}{labelspace}{%
+  \def\bf@leftlabelspace{#1}%
+  \def\bf@rightlabelspace{#1}%
+}
+%    \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \begin{macro}{\KV@bytefield@leftcurlyshrinkage}
+% \begin{macro}{\KV@bytefield@rightcurlyshrinkage}
+% \begin{macro}{\KV@bytefield@curlyshrinkage}
+% Specify the number of points by which to reduce the height of a curly
+% brace (left, right, or both) so its ends don't overlap whatever's
+% above or below it.
+%    \begin{macrocode}
+\define@key{bytefield}{leftcurlyshrinkage}{\def\bf@leftcurlyshrinkage{#1}}
+\define@key{bytefield}{rightcurlyshrinkage}{\def\bf@rightcurlyshrinkage{#1}}
+\define@key{bytefield}{curlyshrinkage}{%
+  \def\bf@leftcurlyshrinkage{#1}%
+  \def\bf@rightcurlyshrinkage{#1}%
+}
+%    \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \begin{macro}{\bytefieldsetup}
+% \usermacro
+% \changes{v2.0}{2011/01/18}{Introduced this macro to provide a more
+%   convenient way of configuring \pkgname{bytefield}'s parameters}
+% \begin{macro}{\bf@bytefieldsetup}
+% Reconfigure values for various \pkgname{bytefield} parameters.
+% Internally to the package we use the |\bf@bytefieldsetup| macro
+% instead of |\bytefieldsetup|.  This enables us to redefine
+% |\bytefieldsetup| when entering version~1 compatibility mode without
+% impacting the rest of \pkgname{bytefield}.
+%    \begin{macrocode}
+\newcommand{\bf@bytefieldsetup}{\setkeys{bytefield}}
+\let\bytefieldsetup=\bf@bytefieldsetup
+%    \end{macrocode}
+% \end{macro}
+% \end{macro}
+%
+% We define only a single option that can be used only as a package
+% option, not as an argument to |\bytefieldsetup|: |compat1| instructs
+% \pkgname{bytefield} to enter version~1 compatibility mode---at the
+% cost of a number of additional length registers and the inability to
+% specify parameters in the argument to the |bytefield| environment.
+%    \begin{macrocode}
+\DeclareOption{compat1}{\bf@enter@compatibility@mode@i}
+%    \end{macrocode}
+%
+% \begin{macro}{\bf@package@options}
+% \begin{macro}{\next}
+% We want to use |\bf@bytefieldsetup| to process \pkgname{bytefield}
+% package options.  Unfortunately, |\DeclareOption| doesn't handle
+% \meta{key}=\meta{value} arguments.  Hence, we use |\DeclareOption*| to
+% catch \emph{all} options, each of which it appends to
+% |\bf@package@options|.  |\bf@package@options| is passed to
+% |\bf@bytefieldsetup| only at the beginning of the document so that the
+% options it specifies (a)~can refer to ex-heights and (b)~override the
+% default values, which are also set at the beginning of the document.
+%    \begin{macrocode}
+\def\bf@package@options{}
+\DeclareOption*{%
+  \edef\next{%
+    \noexpand\g@addto@macro\noexpand\bf@package@options{,\CurrentOption}%
+  }%
+  \next
+}
+\ProcessOptions\relax
+\expandafter\bf@bytefieldsetup\expandafter{\bf@package@options}
+%    \end{macrocode}
+% \end{macro}
+% \end{macro}
 %
 % \Finale
 \endinput
diff --git a/Master/texmf-dist/source/latex/bytefield/bytefield.ins b/Master/texmf-dist/source/latex/bytefield/bytefield.ins
index adfda84046e..9eac6249190 100644
--- a/Master/texmf-dist/source/latex/bytefield/bytefield.ins
+++ b/Master/texmf-dist/source/latex/bytefield/bytefield.ins
@@ -1,5 +1,5 @@
 %%
-%% Copyright (C) 2010 by Scott Pakin <scott+bf@pakin.org>
+%% Copyright (C) 2011 by Scott Pakin <scott+bf@pakin.org>
 %%
 %% This file may be distributed and/or modified under the conditions of
 %% the LaTeX Project Public License, either version 1.3a of this license
@@ -21,7 +21,7 @@
 
 This is a generated file.
 
-Copyright (C) 2010 by Scott Pakin <scott+bf@pakin.org>
+Copyright (C) 2011 by Scott Pakin <scott+bf@pakin.org>
 
 This file may be distributed and/or modified under the conditions of
 the LaTeX Project Public License, either version 1.3a of this license
diff --git a/Master/texmf-dist/tex/latex/bytefield/bytefield.sty b/Master/texmf-dist/tex/latex/bytefield/bytefield.sty
index 40ce86b2517..98e039072c7 100644
--- a/Master/texmf-dist/tex/latex/bytefield/bytefield.sty
+++ b/Master/texmf-dist/tex/latex/bytefield/bytefield.sty
@@ -8,7 +8,7 @@
 %% 
 %% This is a generated file.
 %% 
-%% Copyright (C) 2010 by Scott Pakin <scott+bf@pakin.org>
+%% Copyright (C) 2011 by Scott Pakin <scott+bf@pakin.org>
 %% 
 %% This file may be distributed and/or modified under the conditions of
 %% the LaTeX Project Public License, either version 1.3a of this license
@@ -22,13 +22,15 @@
 %% 
 \NeedsTeXFormat{LaTeX2e}[1999/12/01]
 \ProvidesPackage{bytefield}
-    [2010/10/31 v1.3 Network protocol diagrams]
+    [2011/01/25 v2.0 Network protocol diagrams]
 \RequirePackage{calc}[1998/07/07]
+\RequirePackage{keyval}
 \def\bf@newdimen#1{\advance\count11 by 1
-  \ch@ck1\insc@unt\dimen% Check room
+  \ch@ck1\insc@unt\dimen
   \allocationnumber=\count11
   \dimendef#1=\allocationnumber
-  \wlog{\string#1=\string\dimen\the\allocationnumber\space (locally)}}
+  \wlog{\string#1=\string\dimen\the\allocationnumber\space (locally)}%
+}
 \AtBeginDocument{%
   \begingroup\expandafter\expandafter\expandafter\endgroup
   \expandafter\ifx\csname locdimen\endcsname\relax
@@ -44,42 +46,46 @@
   \global\advance\bytefield@height by \bytefield@height@increment}
 \newcounter{bits@wide}
 \newsavebox{\entire@bytefield@picture}
-\newenvironment{bytefield}[1]{%
-  \setcounter{bits@wide}{#1}%
+\newenvironment{bytefield}[2][]{%
+  \bf@bytefieldsetup{#1}%
+  \setcounter{bits@wide}{#2}%
   \let\old@nl=\\%
   \let\amp=&%
   \catcode`\&=10
   \openup -1pt
   \setlength{\bytefield@height}{0pt}%
   \setlength{\unitlength}{1pt}%
-  \counting@wordstrue
+  \global\counting@wordstrue
   \begin{lrbox}{\entire@bytefield@picture}%
   \renewcommand{\\}{%
-    \amp\show@wordlabelr\cr%
-    \ignorespaces\counting@wordstrue\make@lspace\amp}%
-  \vbox\bgroup\ialign\bgroup##\amp##\amp##\cr\amp%
+    \unskip
+    \amp\show@wordlabelr\cr
+    \ignorespaces\global\counting@wordstrue\make@lspace\amp}%
+  \vbox\bgroup\ialign\bgroup##\amp##\amp##\cr\amp
 }{%
-  \amp\show@wordlabelr\cr\egroup\egroup%
+  \amp\show@wordlabelr\cr\egroup\egroup
   \end{lrbox}%
   \usebox{\entire@bytefield@picture}}
-\newlength{\bitwidth}
-\AtBeginDocument{\settowidth{\bitwidth}{\tiny 99i}}
-\newlength{\byteheight}
-\AtBeginDocument{\setlength{\byteheight}{4ex}}
+\newcommand*{\bf@bitformatting}{\tiny}
+\newcommand*{\bf@boxformatting}{\centering}
+\newlength{\bf@bitwidth}
+\settowidth{\bf@bitwidth}{\bf@bitformatting{99i}}
+\newlength{\bf@bitheight}
+\setlength{\bf@bitheight}{4ex}
 \newlength{\units@wide}
 \newlength{\units@tall}
 \DeclareRobustCommand{\bitbox}[3][lrtb]{%
-  \setlength{\units@wide}{\bitwidth * #2}%
+  \setlength{\units@wide}{\bf@bitwidth * #2}%
   \parse@bitbox@arg{#1}%
-  \draw@bit@picture{\strip@pt\units@wide}{\strip@pt\byteheight}{#3}}
+  \draw@bit@picture{\strip@pt\units@wide}{\strip@pt\bf@bitheight}{#3}}
 \DeclareRobustCommand{\wordbox}[3][lrtb]{%
-  \setlength{\units@wide}{\bitwidth * \value{bits@wide}}%
-  \setlength{\units@tall}{\byteheight * #2}%
+  \setlength{\units@wide}{\bf@bitwidth * \value{bits@wide}}%
+  \setlength{\units@tall}{\bf@bitheight * #2}%
   \parse@bitbox@arg{#1}%
   \draw@bit@picture{\strip@pt\units@wide}{\strip@pt\units@tall}{#3}}
 \DeclareRobustCommand{\draw@bit@picture}[3]{%
   \begin{picture}(#1,#2)%
-    \put(0,0){\makebox(#1,#2){\parbox[c]{#1\unitlength}{%
+    \put(0,0){\makebox(#1,#2){\parbox{#1\unitlength}{%
       \bf@newdimen\height
       \bf@newdimen\depth
       \bf@newdimen\totalheight
@@ -90,7 +96,7 @@
       \width=#1\unitlength
       \def\widthunits{#1}%
       \def\heightunits{#2}%
-      \centering #3}}}%
+      \bf@boxformatting{#3\par}}}}%
     \ifbitbox@top
       \put(0,#2){\line(1,0){#1}}
     \fi
@@ -106,7 +112,7 @@
   \end{picture}%
   \ifcounting@words
     \inc@bytefield@height{\unitlength * \real{#2}}%
-    \counting@wordsfalse
+    \global\counting@wordsfalse
   \fi
   \ignorespaces}
 \newif\ifbitbox@top
@@ -141,7 +147,7 @@
   \fi}
 \newlength{\units@high}
 \DeclareRobustCommand{\skippedwords}[1][2ex]{%
-  \setlength{\units@wide}{\bitwidth * \value{bits@wide}}%
+  \setlength{\units@wide}{\bf@bitwidth * \value{bits@wide}}%
   \setlength{\units@high}{1pt * \ratio{\units@wide}{6.0pt}}%
   \setlength{\units@tall}{#1 + \units@high}%
   \edef\num@wide{\strip@pt\units@wide}%
@@ -155,12 +161,12 @@
   \end{picture}%
   \ifcounting@words
     \inc@bytefield@height{\unitlength * \real{\num@tall}}%
-    \counting@wordsfalse
+    \global\counting@wordsfalse
   \fi}
 \DeclareRobustCommand{\bitheader}[2][l]{%
   \parse@bitbox@arg{lrtb}%
-  \setlength{\units@wide}{\bitwidth * \value{bits@wide}}%
-  \setlength{\units@tall}{\heightof{\tiny 9}}%
+  \setlength{\units@wide}{\bf@bitwidth * \value{bits@wide}}%
+  \setlength{\units@tall}{\heightof{\bf@bitformatting{1234567890}}}%
   \setlength{\units@high}{\units@tall * -1}%
   \def\bit@endianness{#1}%
   \begin{picture}(\strip@pt\units@wide,\strip@pt\units@tall)%
@@ -169,7 +175,7 @@
   \end{picture}%
   \ifcounting@words
     \inc@bytefield@height{\unitlength * \real{\strip@pt\units@tall}}%
-    \counting@wordsfalse
+    \global\counting@wordsfalse
   \fi
   \ignorespaces}
 \def\parse@range@list#1,{%
@@ -188,64 +194,76 @@
     \ifnum\value{header@val}<\value{max@header@val}%
       \if\bit@endianness b%
         \setlength{\header@xpos}{%
-          \bitwidth * (\value{bits@wide}-\value{header@val}-1)}
+          \bf@bitwidth * (\value{bits@wide}-\value{header@val}-1)}
       \else
-        \setlength{\header@xpos}{\bitwidth * \value{header@val}}
+        \setlength{\header@xpos}{\bf@bitwidth * \value{header@val}}
       \fi
       \put(\strip@pt\header@xpos,0){%
-        \makebox(\strip@pt\bitwidth,\strip@pt\units@tall){%
-          \tiny \theheader@val}}
+        \makebox(\strip@pt\bf@bitwidth,\strip@pt\units@tall){%
+          \bf@bitformatting{\theheader@val}}}
       \addtocounter{header@val}{1}
   \repeat}
-\newlength{\curlyshrinkage}
-\setlength{\curlyshrinkage}{5pt}
-\newlength{\curlyspace}
-\AtBeginDocument{\setlength{\curlyspace}{1ex}}
-\newlength{\labelspace}
-\AtBeginDocument{\setlength{\labelspace}{0.5ex}}
+\def\bf@leftcurlyshrinkage{5pt}
+\def\bf@rightcurlyshrinkage{5pt}
+\def\bf@leftcurlyspace{0pt}
+\def\bf@rightcurlyspace{0pt}
+\def\bf@leftlabelspace{0pt}
+\def\bf@rightlabelspace{0pt}
+\gdef\bf@leftcurlyspace{1ex}
+\gdef\bf@rightcurlyspace{1ex}
+\gdef\bf@leftlabelspace{0.5ex}
+\gdef\bf@rightlabelspace{0.5ex}
+\let\bf@leftcurly=\{
+\let\bf@rightcurly=\}
 \newbox{\curly@box}
 \def\store@rcurly#1#2{%
   \begingroup
-    \bf@newdimen\curly@height%
-    \setlength{\curly@height}{#2 - \curlyshrinkage}%
-    \bf@newdimen\half@curly@height%
+    \bf@newdimen\curly@height
+    \setlength{\curly@height}{#2 - \bf@rightcurlyshrinkage}%
+    \bf@newdimen\half@curly@height
     \setlength{\half@curly@height}{0.5\curly@height}%
-    \bf@newdimen\curly@shift%
-    \setlength{\curly@shift}{\half@curly@height + 0.5\curlyshrinkage}%
+    \bf@newdimen\curly@shift
+    \setlength{\curly@shift}{\bf@rightcurlyshrinkage}%
+    \setlength{\curly@shift}{\half@curly@height + 0.5\curly@shift}%
     \global\sbox{#1}{\raisebox{\curly@shift}{%
       $\xdef\old@axis{\the\fontdimen22\textfont2}$%
       $\fontdimen22\textfont2=0pt%
-       \left.\vrule height\half@curly@height
-                    width 0pt
-                    depth\half@curly@height\right\}$%
+       \left.
+       \vrule height\half@curly@height
+              width 0pt
+              depth\half@curly@height\right\bf@rightcurly$%
       $\fontdimen22\textfont2=\old@axis$}}%
   \endgroup
 }
 \def\store@lcurly#1#2{%
   \begingroup
-    \bf@newdimen\curly@height%
-    \setlength{\curly@height}{#2 - \curlyshrinkage}%
-    \bf@newdimen\half@curly@height%
+    \bf@newdimen\curly@height
+    \setlength{\curly@height}{#2 - \bf@leftcurlyshrinkage}%
+    \bf@newdimen\half@curly@height
     \setlength{\half@curly@height}{0.5\curly@height}%
-    \bf@newdimen\curly@shift%
-    \setlength{\curly@shift}{\half@curly@height + 0.5\curlyshrinkage}%
+    \bf@newdimen\curly@shift
+    \setlength{\curly@shift}{\bf@leftcurlyshrinkage}%
+    \setlength{\curly@shift}{\half@curly@height + 0.5\curly@shift}%
     \global\sbox{#1}{\raisebox{\curly@shift}{%
       $\xdef\old@axis{\the\fontdimen22\textfont2}$%
       $\fontdimen22\textfont2=0pt%
-       \left\{\vrule height\half@curly@height
-                     width 0pt
-                     depth\half@curly@height\right.$%
+       \left\bf@leftcurly
+       \vrule height\half@curly@height
+              width 0pt
+              depth\half@curly@height\right.$%
       $\fontdimen22\textfont2=\old@axis$}}%
   \endgroup
 }
 \def\show@wordlabelr{}
 \newlength{\wordlabelr@start}
 \newlength{\wordlabelr@end}
-\newenvironment{wordgroupr}[1]{%
+\newenvironment{rightwordgroup}[1]{%
+  \endgroup
   \global\wordlabelr@start=\bytefield@height
   \gdef\wordlabelr@text{#1}%
-  \ignorespaces%
+  \ignorespaces
 }{%
+  \begingroup
   \global\wordlabelr@end=\bytefield@height
   \gdef\show@wordlabelr{%
     \sbox{\word@label@box}{%
@@ -253,27 +271,30 @@
     \settowidth{\label@box@width}{\usebox{\word@label@box}}%
     \setlength{\label@box@height}{\wordlabelr@end-\wordlabelr@start}%
     \store@rcurly{\curly@box}{\label@box@height}%
-    \bf@newdimen\total@box@width%
+    \bf@newdimen\total@box@width
     \setlength{\total@box@width}{%
-      \curlyspace +
+      \bf@rightcurlyspace +
       \widthof{\usebox{\curly@box}} +
-      \labelspace +
+      \bf@rightlabelspace +
       \label@box@width}%
     \begin{picture}(\strip@pt\total@box@width,0)
       \put(0,0){%
-        \hspace*{\curlyspace}%
+        \hspace*{\bf@rightcurlyspace}%
         \usebox{\curly@box}%
-        \hspace*{\labelspace}%
+        \hspace*{\bf@rightlabelspace}%
         \makebox(\strip@pt\label@box@width,\strip@pt\label@box@height){%
           \usebox{\word@label@box}}}
     \end{picture}%
     \gdef\show@wordlabelr{}}%
-  \ignorespaces}
+  \def\@currenvir{rightwordgroup}%
+  \ignorespaces
+}
 \newlength{\wordlabell@start}
 \newlength{\wordlabell@end}
 \newlength{\total@lbox@width}
 \gdef\make@lspace{}
-\newenvironment{wordgroupl}[1]{%
+\newenvironment{leftwordgroup}[1]{%
+  \endgroup
   \global\wordlabell@start=\bytefield@height
   \gdef\wordlabell@text{#1}%
   \sbox{\word@label@box}{%
@@ -281,20 +302,21 @@
   \settowidth{\label@box@width}{\usebox{\word@label@box}}%
   \store@lcurly{\curly@box}{5cm}%
   \setlength{\total@lbox@width}{%
-    \curlyspace +
+    \bf@leftcurlyspace +
     \widthof{\usebox{\curly@box}} +
-    \labelspace +
+    \bf@leftlabelspace +
     \label@box@width}%
   \global\total@lbox@width=\total@lbox@width
   \gdef\make@lspace{%
     \hspace*{\total@lbox@width}%
     \gdef\make@lspace{}}%
-  \ignorespaces%
+  \ignorespaces
 }{%
+  \begingroup
   \global\wordlabell@end=\bytefield@height
   \bf@newdimen\starting@point
   \setlength{\starting@point}{%
-    -\total@lbox@width - \bitwidth*\value{bits@wide}}%
+    -\total@lbox@width - \bf@bitwidth*\value{bits@wide}}%
   \sbox{\word@label@box}{%
     \begin{tabular}[b]{@{}l@{}}\wordlabell@text\end{tabular}}%
   \settowidth{\label@box@width}{\usebox{\word@label@box}}%
@@ -304,14 +326,118 @@
     \put(\strip@pt\starting@point,0){%
       \makebox(\strip@pt\label@box@width,\strip@pt\label@box@height){%
         \usebox{\word@label@box}}%
-      \hspace*{\labelspace}%
+      \hspace*{\bf@leftlabelspace}%
       \usebox{\curly@box}%
-      \hspace*{\curlyspace}}
+      \hspace*{\bf@leftcurlyspace}}
   \end{picture}%
+  \def\@currenvir{leftwordgroup}%
   \ignorespaces}
 \newlength{\label@box@width}
 \newlength{\label@box@height}
 \newsavebox{\word@label@box}
+\newcommand{\bf@enter@compatibility@mode@i}{%
+  \PackageInfo{bytefield}{Entering version 1 compatibility mode}%
+  \newlength{\bitwidth}%
+  \newlength{\byteheight}%
+  \newlength{\curlyspace}%
+  \newlength{\labelspace}%
+  \newlength{\curlyshrinkage}%
+  \settowidth{\bitwidth}{\tiny 99i}%
+  \setlength{\byteheight}{4ex}%
+  \setlength{\curlyspace}{1ex}%
+  \setlength{\labelspace}{0.5ex}%
+  \setlength{\curlyshrinkage}{5pt}%
+  \let\newbytefield=\bytefield
+  \let\endnewbytefield=\endbytefield
+  \renewenvironment{bytefield}[1]{%
+    \begin{newbytefield}[%
+      bitwidth=\bitwidth,
+      bitheight=\byteheight,
+      curlyspace=\curlyspace,
+      labelspace=\labelspace,
+      curlyshrinkage=\curlyshrinkage]{##1}%
+  }{%
+    \end{newbytefield}%
+  }
+  \def\wordgroupr{\begin{rightwordgroup}}
+  \def\endwordgroupr{\end{rightwordgroup}}
+  \def\wordgroupl{\begin{leftwordgroup}}
+  \def\endwordgroupl{\end{leftwordgroup}}
+  \renewcommand{\bytefieldsetup}[1]{%
+    \PackageError{bytefield}{%
+      The \protect\bytefieldsetup\space macro is not available in\MessageBreak
+      version 1 compatibility mode%
+    }{%
+      Remove [compat1] from the \protect\usepackage{bytefield} line to
+      make \protect\bytefieldsetup\MessageBreak
+      available to this document.\space\space (The document may also need
+      to be modified to use\MessageBreak
+      the new bytefield interface.)
+    }%
+  }%
+}
+\newcommand{\wordgroupr}{%
+  \PackageError{bytefield}{%
+    Macros \protect\wordgroupr, \protect\wordgroupl, \protect\endwordgroupr,
+    \MessageBreak
+    and \protect\endwordgroupl\space no longer exist%
+  }{%
+    Starting with version 2.0, bytefield uses \protect\begin{wordgroupr}...
+    \MessageBreak
+    \protect\end{wordgroupr} and \protect\begin{wordgroupl}...%
+    \protect\end{wordgroupl}\MessageBreak
+    to specify word groups and a new \protect\bytefieldsetup\space macro to
+    \MessageBreak
+    change bytefield's various formatting parameters.%
+  }%
+}
+\let\endwordgroupr=\wordgroupr
+\let\wordgroupl=\wordgroupr
+\let\endwordgroupl=\wordgroupr
+\define@key{bytefield}{bitwidth}{%
+  \def\bf@bw@arg{#1}%
+  \def\bf@auto{auto}%
+  \ifx\bf@bw@arg\bf@auto
+    \settowidth{\bf@bitwidth}{\bf@bitformatting{99i}}%
+  \else
+    \setlength{\bf@bitwidth}{#1}%
+  \fi
+}
+\define@key{bytefield}{bitheight}{\setlength{\bf@bitheight}{#1}}
+\define@key{bytefield}{bitformatting}{\def\bf@bitformatting{#1}}
+\define@key{bytefield}{boxformatting}{\def\bf@boxformatting{#1}}
+\define@key{bytefield}{leftcurly}{\def\bf@leftcurly{#1}}
+\define@key{bytefield}{rightcurly}{\def\bf@rightcurly{#1}}
+\define@key{bytefield}{leftcurlyspace}{\def\bf@leftcurlyspace{#1}}
+\define@key{bytefield}{rightcurlyspace}{\def\bf@rightcurlyspace{#1}}
+\define@key{bytefield}{curlyspace}{%
+  \def\bf@leftcurlyspace{#1}%
+  \def\bf@rightcurlyspace{#1}%
+}
+\define@key{bytefield}{leftlabelspace}{\def\bf@leftlabelspace{#1}}
+\define@key{bytefield}{rightlabelspace}{\def\bf@rightlabelspace{#1}}
+\define@key{bytefield}{labelspace}{%
+  \def\bf@leftlabelspace{#1}%
+  \def\bf@rightlabelspace{#1}%
+}
+\define@key{bytefield}{leftcurlyshrinkage}{\def\bf@leftcurlyshrinkage{#1}}
+\define@key{bytefield}{rightcurlyshrinkage}{\def\bf@rightcurlyshrinkage{#1}}
+\define@key{bytefield}{curlyshrinkage}{%
+  \def\bf@leftcurlyshrinkage{#1}%
+  \def\bf@rightcurlyshrinkage{#1}%
+}
+\newcommand{\bf@bytefieldsetup}{\setkeys{bytefield}}
+\let\bytefieldsetup=\bf@bytefieldsetup
+\DeclareOption{compat1}{\bf@enter@compatibility@mode@i}
+\def\bf@package@options{}
+\DeclareOption*{%
+  \edef\next{%
+    \noexpand\g@addto@macro\noexpand\bf@package@options{,\CurrentOption}%
+  }%
+  \next
+}
+\ProcessOptions\relax
+\expandafter\bf@bytefieldsetup\expandafter{\bf@package@options}
 \endinput
 %%
 %% End of file `bytefield.sty'.