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authorKarl Berry <karl@freefriends.org>2006-01-09 00:49:07 +0000
committerKarl Berry <karl@freefriends.org>2006-01-09 00:49:07 +0000
commit007f67a693e4d031fd3d792df8e4d5f43e2cb2e7 (patch)
tree90d17e00e572ecb1e24764b6f29c80e098b08d29 /Master/texmf-dist/doc/latex/msc
parent950209b26f70aa87ed07c54f82a95b6f03b7c3a0 (diff)
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git-svn-id: svn://tug.org/texlive/trunk@84 c570f23f-e606-0410-a88d-b1316a301751
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-rw-r--r--Master/texmf-dist/doc/latex/msc/COPYRIGHT28
-rw-r--r--Master/texmf-dist/doc/latex/msc/README43
-rw-r--r--Master/texmf-dist/doc/latex/msc/maintenance.tex257
-rw-r--r--Master/texmf-dist/doc/latex/msc/manual.tex2834
-rw-r--r--Master/texmf-dist/doc/latex/msc/refman.tex1672
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diff --git a/Master/texmf-dist/doc/latex/msc/COPYRIGHT b/Master/texmf-dist/doc/latex/msc/COPYRIGHT
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+%% MSC Macro Package
+%% msc.sty
+%% Version 1.14
+%% March 15, 2004
+%%
+%% Copyright 2002 V. Bos and S. Mauw
+%
+% This program may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.2
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+% http://www.latex-project.org/lppl.txt
+% and version 1.2 or later is part of all distributions of LaTeX
+% version 1999/12/01 or later.
+%
+% This program consists of the files
+% msc.sty
+% manual.tex
+% manual.ps
+% refman.tex
+% refman.ps
+% biblio.bib
+% maintenance.tex
+% maintenance.ps
+% README
+% COPYRIGHT
+
+
diff --git a/Master/texmf-dist/doc/latex/msc/README b/Master/texmf-dist/doc/latex/msc/README
new file mode 100644
index 00000000000..eea9428f21b
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@@ -0,0 +1,43 @@
+MSC Macro Package
+-----------------
+Version 1.14
+March 15, 2004
+
+----------------------------------------------------------------------
+Copyright 2002 V. Bos and S. Mauw
+
+This program may be distributed and/or modified under the
+conditions of the LaTeX Project Public License, either version 1.2
+of this license or (at your option) any later version.
+The latest version of this license is in
+ http://www.latex-project.org/lppl.txt
+and version 1.2 or later is part of all distributions of LaTeX
+version 1999/12/01 or later.
+
+This program consists of the files
+ msc.sty
+ manual.tex
+ manual.ps
+ refman.tex
+ refman.ps
+ biblio.bib
+ maintenance.tex
+ maintenance.ps
+ README
+ COPYRIGHT
+
+----------------------------------------------------------------------
+
+The MSC macro package is a LaTeX2e package to draw MSC diagrams. See
+user manual (manual.ps) and reference manual (refman.ps) for more
+information.
+
+Contact address:
+S. Mauw
+Eindhoven University of Technology
+P.O. Box 513
+5600 MB Eindhoven
+The Netherlands
+Email: sjouke@win.tue.nl, vbos@abo.fi
+Updates via: http://www.win.tue.nl/~sjouke/mscpackage.html
+and via CTAN directory: macros/latex/contrib/msc/
diff --git a/Master/texmf-dist/doc/latex/msc/maintenance.tex b/Master/texmf-dist/doc/latex/msc/maintenance.tex
new file mode 100644
index 00000000000..67eb3479a9c
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/msc/maintenance.tex
@@ -0,0 +1,257 @@
+% file: maintenance.tex
+% Copyright 2002 V. Bos and S. Mauw
+% This file is part of the MSC Macro Package.
+%
+% RCS version: $Id: maintenance.tex,v 1.11 2004/03/15 11:40:27 vbos Exp $
+%
+\documentclass{article}
+\usepackage{a4wide}
+\usepackage{msc}
+
+\title{
+ A {\LaTeX{}} macro package for Message Sequence Charts---Maintenance
+ document
+}
+
+\author{
+ \begin{tabular}{cc}
+ Victor Bos & Sjouke Mauw\\
+ \footnotesize Turku Centre for Computer Science &
+ \footnotesize Eindhoven University of Technology \\ [-0.8ex]
+ \footnotesize Software Construction Laboratory &
+ \footnotesize Department of Mathematics and Computing Science \\ [-0.8ex]
+ \footnotesize Lemminkäisenkatu 14 &
+ \footnotesize P.O.\ Box 513 \\ [-0.8ex]
+ \footnotesize FIN--20520 Turku &
+ \footnotesize NL--5600 MB Eindhoven \\ [-0.8ex]
+ \footnotesize Finland &
+ \footnotesize The Netherlands \\
+ \footnotesize \texttt{vbos@abo.fi} &
+ \footnotesize \texttt{sjouke@win.tue.nl}
+ \end{tabular}
+}
+
+
+\begin{document}
+
+\date{\small Version \mscversion, last update \today}
+
+\maketitle
+
+\begin{abstract}
+\noindent
+The MSC macro package facilitates the \LaTeX\ user to easily include
+Message Sequence Charts in his texts. This document contains
+information which supports the maintenance of the package.
+\end{abstract}
+
+\section{Introduction}
+This document contains three lists related to the maintenance of the
+MSC macro package. This is a \LaTeX\ package for drawing Message
+Sequence Charts.
+For additional information consult the following URL:
+\verb+http://www.win.tue.nl/~sjouke/mscpackage.html+.
+
+The first list contains an overview of all publicly released versions
+of the MSC macro package. The second list contains all known (yet
+unresolved) bugs of the MSC macro package. The third list is the wish
+list, containing wishes expressed by the users of the package w.r.t.
+desired additional functionality.
+
+\section{Versions}
+\begin{itemize}
+\item Version 1.0, First public release, 1999/03/16.
+
+Supports drawing of the following MSC constructs: MSC frame,
+instances, messages (including self and env messages), coregions.
+Includes some parameters for fine tuning of the drawing.
+
+\item Version 1.1, Public release, 1999/03/24.
+
+Minor bug fixes.
+Additionally supports: timers (singular events), lost and found
+messages, generalized ordering. Extra parameters:
+\verb+\lostsymbolradius+, \verb+\timerwidth+. The macro
+\verb+\setfootcolor+ replaces \verb+\setfootgrayness+, and the macro
+\verb+\setmscvalues+ replaces \verb+\resetmsclengths+.
+Some default values have been adjusted.
+
+\item Version 1.2, Public release, 1999/03/29.
+
+Minor bug fixes.
+Code restructuring.
+Additionally supports: Actions.\\
+Extra parameters:
+\verb+\actionheight+, \verb+\actionwidth+.
+
+\item Version 1.3, Public release, 1999/04/10.
+
+Minor bug fixes.
+Additionally supports: Conditions, combined timer symbols, instance
+stop.\\
+Extra parameters:
+\verb+\conditionheight+, \verb+\conditionoverlap+, \verb+\stopwidth+.
+Leveloffset can be specified in \verb+nextlevel+ command.
+
+\item Version 1.4, Public release, 1999/04/23.
+
+Minor bug fixes.\\
+Additionally supports: Instance creation, MSC references, and inline
+expressions.\\
+Extra parameters:
+\verb+\referenceoverlap+, \verb+\inlineoverlap+, \verb+\stopwidth+.\\
+Adjustment of default values. There are now three sizes
+(large/normal/small) instead of two. The middle size is now default.\\
+New command \verb+\setmscscale+ to scale the complete MSC up/down.
+
+
+
+\item Version 1.10, Public release, 2002/04/10.
+
+Major improvements: support for two new types of diagrams: High-level
+MSCs and MSC documents. Additional MSC constructs: fat (double line)
+instances, gates, time measurements, comments, instance regions
+(activation, suspension, and co-regions), method replies (dashed
+message arrows). Left and right overlap of inline expressions and MSC
+references in an MSC diagram can be specified separately.
+
+Reference manual. For a list of (all) commands and lengths, see
+reference manual.
+
+Package now also available at CTAN.
+
+\item Version 1.10a, Public release, 2002/04/11.
+
+Minor bug fixes.\\
+The email addresses and websites mentioned in the files have been
+corrected (if necessary).
+
+The problem with the german package (german.sty) has been solved. This
+bug was found by Christian Kaeunicke. The german package redefines the
+meaning of the " symbol in order to type german texts more
+efficiently. However, this was not compatible with the msc package
+(before version 1.10a), because it uses the " symbol in
+(error)-messages. The new version (1.10a) uses the ' symbol instead of
+the " symbol. This seems to solve the problem with the german
+package. However, there are probably packages assigning special
+meaning to the ' symbol and which will therefore not work properly
+with the msc package.
+
+\item Version 1.11, Public release, 2002/06/06.
+
+Minor bug fix.\\ The \verb+\stepcounter+ problem that occurred while
+using the MSC Macro Package together with overlays (slides) is solved.
+
+\item Version 1.12, beta release, 2002/06/18.
+
+In this version, the user has more control over the positioning of
+message labels. Implementation not finished yet.
+
+\item Version 1.13, beta release, 2002/06/27.
+
+The label positioning of version 1.12 is reimplemented. In fact, the
+implementation of messages is rewritten completely. The same method to
+compute the location of labels is used in \verb+\mess+, \verb+create+,
+\verb+lost+, and \verb+found+. The new implementation is backward
+compatible, meaning that old documents using the MSC Macro Package
+will still look the same.
+
+In addition, the bounding box bug is partly fixed. An \verb+\fbox+ is
+drawn around each msc, hmsc, and mscdoc diagram. This enables dvips to
+compute the right bounding box. Since the \verb+\fbox+ is drawn in
+white, there is no visible result as long as the background is white,
+too. A consequence of this bug fix is that the MSC Macro package
+requires the \textsf{color} package. Just like the other required
+packages, \textsf{pstricks}, \textsf{calc}, and \textsf{ifthen}, this
+is a standard \LaTeXe{} package.
+
+\item Version 1.14, Public release, 2004/03/15.
+
+This version fixes a bug in the drawing routine of messages. In
+earlier versions, the arrow heads of messages were sometimes
+positioned at the center of an instance axis, even though the instance
+was an activation region.
+
+\end{itemize}
+
+\section{Bugs}
+The MSC macro package contains numerous bugs (and hidden features).
+As of now, these are the only ones that have revealed themselves in public.
+
+\begin{itemize}
+
+\item Some starred versions of commands of the MSC Macro package do
+not cooperate with the \textsf{amsbsy} package. The problem is that
+the latter package redefined the macro \verb+\@ifstar+. This bug was
+dicovered by Sjouke Mauw.
+
+\item The size of msc diagrams is computed incorrectly. After
+generating an eps file (dvips -E) from a dvi file containing exactly
+one msc diagram, the diagram is clipped incorrectly. This bug was
+dicovered by Tim Willemse.
+
+\item There are \LaTeX{} packages that assign special meaning to some
+characters. Consequently, the  MSC Macro package might not function properly
+with such packages. Since we cannot anticipate on these semantical
+changes of symbols, we don't know of a good solution to it. However,
+we try to find solutions for these problems if they originated from
+packages that are in the standard \LaTeX{} distribution.
+
+A concrete example was the \textsf{german} package, as pointed out by
+Christian Kaeunicke. This package assigns special meaning to the "
+symbol. If you issue \verb+\usepackage{german}+ \emph{before}
+\verb+\usepackage{msc}+, you will get an error as soon as your first
+msc diagram is compiled. As Christian also mentioned, the error does
+not occur if the import order of the packages is reversed.
+
+As of MSC Macro package version 1.10a, this concrete bug with the
+\textsf{german} package has been solved and the order between
+\textsf{msc} and \textsf{german} is not restricted anymore.
+
+\item The MSC Macro Package (version $\leq 1.10a$) crashes with the
+overlay environment of the slides document class. The bug is due to a
+redefinition of the \verb+\refstepcounter+ macro by the slides
+documentclass. This bug was discovered by Volker Stolz. He and Markus
+Mohnen proposed a solution: increase the counters used by the MSC
+macro package manually. In Version~1.11 this solution is
+implemented. Thanks Volker and Markus!
+
+\item The MSC Macro Package (version $\leq 1.13$) sometimes draws
+arrow heads at the wrong place. Paulo S\'ergio Almeida discovered this
+for messages drawn from right to left and for which the receiver
+instance is an activation region. In fact, as Paulo noticed, the
+manual contains an example of this bug, see Section~6.12 of the
+manual. He also provided some \LaTeX{} code to fix the big. In
+version~1.14, this code replaces the erroneous code.
+
+\end{itemize}
+
+\section{Wishes}
+\begin{itemize}
+
+\item Make the parameters of the MSC Macro package more
+consistent. For example, the \verb+\mess+ macro and the
+\verb+\measure+ have similar positioning parameters, but they cannot
+have the same values. (V. Bos 2002/06/16)
+
+\item Add a section to the user manual describing how to generate
+other formats (like html, PostScript, pdf). (S. Mauw 2002/06/14)
+
+\item Add to the user manual a figure describing the various HMSC lengths.
+ (S. Mauw 2002/06/14)
+
+\item Add automatic resizing of action symbols, as described in one of
+the tricks in the reference manual. (S. Mauw 2002/06/14)
+
+\item Add UML extensions to the MSC Macro package. Describe clearly
+which UML diagrams we support.(S. Mauw, 2002/06/13)
+
+\item Add option to messages to determine relative position of
+label. S. Mauw (sjouke@win.tue.nl), 1999/04/15.
+
+\item A possibility to change the color of instance regions. V. Bos
+(09/04/2002).
+
+\end{itemize}
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/msc/manual.tex b/Master/texmf-dist/doc/latex/msc/manual.tex
new file mode 100644
index 00000000000..a032b52de25
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/msc/manual.tex
@@ -0,0 +1,2834 @@
+% file: manual.tex
+% Copyright 2002 V. Bos and S. Mauw
+% This file is part of the MSC Macro Package.
+%
+% RCS version: $Id: manual.tex,v 1.9 2004/03/15 11:35:47 vbos Exp $
+%
+\documentclass[12pt,a4paper]{article}
+\usepackage{a4wide}
+\usepackage{url}
+\usepackage{moreverb}
+\usepackage{graphicx}
+\usepackage{multicol}
+\usepackage{msc}
+
+% we allow a ragged right
+\setlength{\rightskip}{0pt plus 0.05\linewidth minus 0pt}
+
+
+
+
+
+\newlength{\rpwidth}
+\setlength{\rpwidth}{.5cm}
+\newlength{\rpheight}
+\setlength{\rpheight}{0.5\levelheight}
+\newcommand{\rpN}{%
+ \psframe(-0.5\rpwidth,-\rpheight)(0.5\rpwidth,0\rpheight)%
+ \rput[B](0\rpwidth,-0.8\rpheight){\tiny \textsc{n}}%
+ \pscircle[fillstyle=solid,fillcolor=black](0\rpwidth,0\rpheight){.5\labeldist}%
+}
+\newcommand{\rpNE}{%
+ \psframe(-\rpwidth,-\rpheight)(0\rpwidth,0\rpheight)%
+ \rput[B](-.5\rpwidth,-0.8\rpheight){\tiny \textsc{ne}}%
+ \pscircle[fillstyle=solid,fillcolor=black](0\rpwidth,0\rpheight){.5\labeldist}%
+}
+\newcommand{\rpE}{%
+ \psframe(-\rpwidth,-.5\rpheight)(0\rpwidth,.5\rpheight)%
+ \rput[B](-.5\rpwidth,-0.3\rpheight){\tiny \textsc{e}}%
+ \pscircle[fillstyle=solid,fillcolor=black](0\rpwidth,0\rpheight){.5\labeldist}%
+}
+\newcommand{\rpSE}{%
+ \psframe(-\rpwidth,0\rpheight)(0\rpwidth,\rpheight)%
+ \rput[B](-.5\rpwidth,0.2\rpheight){\tiny \textsc{se}}%
+ \pscircle[fillstyle=solid,fillcolor=black](0\rpwidth,0\rpheight){.5\labeldist}%
+}
+\newcommand{\rpS}{%
+ \psframe(-.5\rpwidth,\rpheight)(.5\rpwidth,0\rpheight)%
+ \rput[t](0\rpwidth,0.8\rpheight){\tiny \textsc{s}}%
+ \pscircle[fillstyle=solid,fillcolor=black](0\rpwidth,0\rpheight){.5\labeldist}%
+}
+\newcommand{\rpSW}{%
+ \psframe(0\rpwidth,0\rpheight)(\rpwidth,\rpheight)%
+ \rput[B](.5\rpwidth,0.2\rpheight){\tiny \textsc{sw}}%
+ \pscircle[fillstyle=solid,fillcolor=black](0\rpwidth,0\rpheight){.5\labeldist}%
+}
+\newcommand{\rpW}{%
+ \psframe(0\rpwidth,-.5\rpheight)(\rpwidth,.5\rpheight)%
+ \rput[B](.5\rpwidth,-0.3\rpheight){\tiny \textsc{w}}%
+ \pscircle[fillstyle=solid,fillcolor=black](0\rpwidth,0\rpheight){.5\labeldist}%
+}
+\newcommand{\rpNW}{%
+ \psframe(0\rpwidth,-\rpheight)(\rpwidth,0\rpheight)%
+ \rput[B](.5\rpwidth,-0.8\rpheight){\tiny \textsc{nw}}%
+ \pscircle[fillstyle=solid,fillcolor=black](0\rpwidth,0\rpheight){.5\labeldist}%
+}
+
+
+
+
+
+% The following code is taken from the doc package. It defines a global
+% macro \bslash that produces a bslash (if present in the current font).
+\makeatletter
+{\catcode`\|=\z@ \catcode`\\=12 |gdef|bslash{\}}
+\makeatother
+\newcommand{\cmd}[1]{\texttt{\bslash #1}}
+
+\newcommand{\acro}[1]{{#1}}
+
+\newcommand{\MSC}{\acro{MSC}}
+\newcommand{\HMSC}{\acro{HMSC}}
+\newcommand{\MSCdoc}{\MSC{}doc}
+\newcommand{\mscpack}{\MSC{} macro package}
+
+\newcommand{\env}[1]{\texttt{#1}}
+\newcommand{\opt}[1]{[#1]}
+\newcommand{\cmdarg}[1]{\{\emph{#1}\}}
+\newcommand{\coordarg}[1]{\emph{#1}}
+\newcommand{\coordargs}[2]{(\coordarg{#1},\coordarg{#2})}
+\newcommand{\lnsvalue}[3]{large/normal/small value #1/#2/#3}
+
+\newenvironment{defs}{%
+ \begin{list}{}%
+ {\setlength{\labelwidth}{0pt}%
+ \setlength{\labelsep}{1em}%
+ \setlength{\leftmargin}{1em}%
+ \setlength{\parsep}{1ex}%
+ \setlength{\listparindent}{0pt}%
+ \setlength{\rightmargin}{0pt}%
+ \renewcommand{\makelabel}[1]{##1}%
+ \raggedright%
+ }%
+ }{%
+ \end{list}}
+
+
+
+\title{
+ A \LaTeX\ macro package for Message Sequence Charts\\{\large User Manual}
+}
+
+\author{
+ \begin{tabular}{cc}
+ Victor Bos & Sjouke Mauw\\
+ \footnotesize Turku Centre for Computer Science &
+ \footnotesize Eindhoven University of Technology \\ [-0.8ex]
+ \footnotesize Software Construction Laboratory &
+ \footnotesize Department of Mathematics and Computing Science \\ [-0.8ex]
+ \footnotesize Lemmink\"aisenkatu 14 &
+ \footnotesize P.O.\ Box 513 \\ [-0.8ex]
+ \footnotesize FIN--20520 Turku &
+ \footnotesize NL--5600 MB Eindhoven \\ [-0.8ex]
+ \footnotesize Finland &
+ \footnotesize The Netherlands \\
+ \footnotesize \texttt{vbos@abo.fi} &
+ \footnotesize \texttt{sjouke@win.tue.nl}
+ \end{tabular}
+}
+
+\date{\small Version \mscversion, last update \today\\
+ Describing \mscpack{} version \mscversion}
+
+\begin{document}
+
+
+\maketitle
+
+\begin{abstract}
+\noindent
+The \mscpack{} facilitates the \LaTeX\ user to easily include
+Message Sequence Charts in his texts. This document describes the
+design and use of the \mscpack.
+\end{abstract}
+
+\tableofcontents
+\section{New}
+\label{new}
+
+\paragraph{Version~1.13} has a reimplementation of message commands in MSC
+diagrams. The affected commands are: \verb+\create+, \verb+\found+,
+\verb+\lost+, \verb+\mess+, and \verb+\order+. The new implementation
+provides more control over the placement of message labels.
+
+The command \verb+\selfmesslabelpos+ has been removed.
+
+The bounding box bug has been partly solved. Now, a white \verb+\fbox+
+is drawn around every (msc, mscdoc, hmsc) diagram. This makes it
+possible for \texttt{dvips -E} to compute the correct bounding box for
+the diagrams. Due to the \verb+\fbox+, each diagram is extended with
+0.3pt on each side (left, top, right, and bottom). This bugfix fails
+if the background is not white. The xdvi program shows the white
+\verb+\fbox+ in black with the result that diagrams have two visible
+frames. This seems to be a bug of xdvi.
+
+The lines around comments (\verb+\msccomment+, Section~\ref{comments})
+are changed from gray into black. The reason for this is that the gray
+lines became invisible after converting the document to HTML.
+
+\paragraph{Version~1.12} is a non-public version. It features a preliminary
+implementation of message label position control.
+
+\paragraph{Version~1.11} is a mainly a bugfix of version~1.10a, see~\cite{BM02b}.
+The next list shows the new features of version~1.10a compared to
+version 1.4.
+
+\begin{itemize}
+\item Support for method replies (dashed message arrows):\cmd{mess*} (Section~\ref{messages})
+\item Fat instances, i.e., double line instances (Section~\ref{instances})
+\item Comments (Section~\ref{comments})
+\item Coregions are now special cases of regions (which includes also
+activation and suspension regions). The \cmd{coregionstart} and
+\cmd{coregionend} commands are obsolete and the \cmd{coregionbarwidth}
+is replaced by \cmd{regionbarwidth}.
+\item Gates (Section~\ref{gates})
+\item High-level \MSC{}'s (Section~\ref{hmsc})
+\item \cmd{inlinestart} has additional optional argument to allow for different left and right overlap (Section~\ref{inlines})
+\item \MSCdoc{}s (Section~\ref{mscdoc})
+\item Reference manual~\cite{BM02}
+\item \cmd{referencestart} has additional optional argument to allow for different left and right overlap (Section~\ref{references})
+\item Regions: generalization of coregions supporting activations, suspension, and coregions (Section~\ref{regions})
+\item Time measurements (Section~\ref{measurements})
+\end{itemize}
+
+
+\section{Introduction}
+\label{introduction}
+
+The \MSC{} language is a visual language for the description of the
+interaction between different components of a system.
+This language is standardized by the ITU (International
+Telecommunication Union) in Recommendation Z.120~\cite{z120}. An
+introductory text on \MSC{} can be found
+in~\cite{RudolphGrabowskiGraubmann96}. \MSC{}s have a
+wide application domain, ranging from requirements specification to
+testing and documentation.
+An example of a Message Sequence Chart is in Figure~\ref{quick}.
+
+In order to support easy drawing of \MSC{}s in \LaTeX\ documents, we have
+developed the \mscpack. The current version of the \mscpack{}
+supports the following \MSC{} constructs: \MSC{} frame, instances (both
+single line width and double line width), messages (including
+self-messages and messages to the environment), actions, singular and
+combined timer events (set, timeout, reset, set-timeout, set-stop),
+lost and found messages, generalized order, conditions, coregions,
+activation regions, suspension regions, gates, instance creation,
+instance stop, time measurements, references, and inline
+expressions. In addition, there is support for \HMSC{}'s (high-level
+\MSC{}s) and \MSCdoc{}s.
+
+In this manual we explain the design and the use of the \mscpack. For
+a complete overview of all features, we refer to the reference
+manual~\cite{BM02}, which is included in the distribution under the
+name \verb+refman.ps+. Another way to learn how to use the \mscpack{}
+is to have a look at the \LaTeX{} source code of the manual and the
+source code of the reference manual. They are included in the
+distribution under the names \verb+manual.tex+ and \verb+refman.tex+,
+respectively. The \MSC{} constructs are simply introduced as
+syntactic constructs. This paper is not meant to describe their use or
+meaning.
+
+We list the backgrounds of the package and some design decisions in
+Section~\ref{background}.
+Section~\ref{install} contains notes on installing the
+package. Section~\ref{quickstart} contains an example of using the
+package. It allows the impatient reader to quickly start using the
+package. The details of using the package are explained in
+Section~\ref{use}. In Section~\ref{parameters} the parameters are
+explained which determine detailed layout of the various symbols.
+A large but meaningless example is given in
+Section~\ref{example}.
+
+
+\section{Background and motivation}
+\label{background}
+Several commercial and non-commercial tools are available, which
+support drawing or generating Message Sequence Charts. However, these
+tools are in general not freely available and often not flexible
+enough to satisfy all user's wishes with respect to the layout and
+graphical appearance of an \MSC{}.
+Therefore, people often use general drawing tools, such as {\em xfig}
+to draw \MSC{}s. However flexible this approach is, it takes quite some
+effort to produce nice \MSC{} drawings in a tool which is not dedicated
+to \MSC{}s. Furthermore, when drawing a number of \MSC{}s it requires some
+preciseness in order to obtain a consistent set of \MSC{}s.
+
+For these reasons, we have started the design of a set of
+\LaTeX\ macros which support the drawing of \MSC{}s. In this way, an \MSC{} can be
+represented in \LaTeX\ in a textual format and compiled into
+e.g.\ PostScript.
+
+We aimed at satisfying the following requirements and design
+decisions.
+\begin{itemize}
+\item
+The package should follow the ITU standard with respect to shape and
+placement of the symbols. (The current version supports
+the \MSC2000 standard.)
+\item
+Static and dynamic semantics are not considered. The user is allowed
+to violate all semantical restrictions and draw inconsistent \MSC{}s.
+The package only supports elementary syntactical requirements.
+\item
+The package should offer functionality at the right level of
+abstraction. Rather than supplying coordinates of pixels, the
+user should be able to express the placement of symbols in terms of
+{\em levels}.
+Nevertheless, the textual representation of \MSC{}s as defined by the ITU
+standard has a level of abstraction which is too high for our purposes.
+It lacks information about the actual positioning of the \MSC{} symbols,
+while we think that in our package this should be under user control.
+\item
+There should be only minimal automatic restructuring and layout of the
+\MSC{} (e.g.\ the relative positioning of two messages should be as
+defined by the user, even if the messages are not causally ordered).
+\item
+The user can customize the appearance of the \MSC{}s by manipulating
+an appropriate set of parameters.
+\end{itemize}
+
+\section{Installation, copyright and system requirements}
+\label{install}
+
+The \mscpack{} is still under development. The authors
+appreciate any comments and suggestions for improvements. The most
+recent version of the package can be downloaded from
+\url{http://www.win.tue.nl/~sjouke/mscpackage.html}.
+
+
+The \mscpack{} has a \emph{LaTeX Project Public License}
+(LPPL), see~\url{http://www.latex-project.org/lppl.txt}:
+{\small
+\verbatiminput{COPYRIGHT}
+} As such, it is free of charge and can be freely
+distributed. Furthermore, it is allowed to make modifications to the
+package, provided that modified versions get different names. The
+authors accept no liability with respect to the functioning of the
+package.
+
+The \mscpack{} runs with \LaTeXe. It has been tested with \LaTeXe\
+version dated 1998/06/01 using \TeX\ version 3.14159. The following
+additional packages are required: \textsf{pstricks}, \textsf{calc},
+\textsf{ifthen}, and \textsf{color}. These packages are in general
+part of the standard \LaTeXe\ distribution. These additional packages
+can be obtained from the {\em ctan} database for \LaTeX\, e.g.\ via
+the following URL: \url{http://www.tex.ac.uk/}. The \textsf{pstricks}
+package is described in~\cite[Chapter~4]{GSM97}. The generated output
+can only be previewed with recent previewing software (e.g.\ xdvi
+version 20c). It may be needed to update all \LaTeX\ related software
+to a more recent version in order to smoothly work with the \mscpack.
+
+The \mscpack{} can be installed easily. Just put the file
+\verb+msc.sty+ in a directory which is searched by \LaTeX{} for style
+files. The set of directories actually searched depends on the \TeX\
+installation, but often the {\em current directory} is included. UNIX
+users may have to set the environment variable \texttt{\$TEXINPUTS} to
+an appropriate value. For more details on this topic consult
+documentation of your \TeX\ installation.
+
+%The following text is currently not applicable -sm
+%
+%A problem may occur when using more packages than the \MSC{} macro
+%package in your \LaTeX\ document. This happens, e.g.\ when using the
+%{\em epsfig} package. These problems are due to the combination of
+%several packages which are required (but not provided) by the \MSC{}
+%macro package. The solution is to change the order of the
+%\verb+usepackage+ clauses.
+
+\section{Quick start}
+\label{quickstart}
+The \mscpack{} is easy to use.
+Below is an example of the use of the package and
+Figure~\ref{quick} shows the generated \MSC{}.
+
+{\small
+\begin{verbatim}
+\documentclass{article}
+\usepackage{msc}
+\begin{document}
+
+\begin{msc}{Example}
+
+\declinst{usr}{User}{}
+\declinst{m1}{Machine 1}{control}
+\declinst{m2}{Machine 2}{drill}
+\declinst{m3}{Machine 3}{test}
+
+\mess{startm1}{usr}{m1}
+\nextlevel
+\mess{startm2}{m1}{m2}
+\nextlevel
+\mess{continue}{m2}{m3}
+\mess{log}{m1}{envleft}
+\nextlevel
+\mess{output}{m3}{usr}[2]
+\nextlevel
+\mess{free}{m1}{usr}
+\nextlevel
+
+\end{msc}
+
+\end{document}
+
+\end{verbatim}
+}
+
+\begin{figure}[htb]
+\begin{center}
+
+\begin{msc}{Example}
+
+\declinst{usr}{User}{}
+\declinst{m1}{Machine 1}{control}
+\declinst{m2}{Machine 2}{drill}
+\declinst{m3}{Machine 3}{test}
+
+\mess{startm1}{usr}{m1}
+\nextlevel
+\mess{startm2}{m1}{m2}
+\nextlevel
+\mess{continue}{m2}{m3}
+\mess{log}{m1}{envleft}
+\nextlevel
+\mess{output}{m3}{usr}[2]
+\nextlevel
+\mess{free}{m1}{usr}
+\nextlevel
+
+\end{msc}
+
+\end{center}
+\caption{The generated \MSC{}}
+\label{quick}
+\end{figure}
+
+The \mscpack{} is activated by the clause
+\verb+\usepackage{msc}+.
+This package contains, among others, a
+definition of the environment \verb+msc+.
+This environment is used to draw \MSC{}s. The \MSC{} definition is surrounded by
+the clauses \verb+\begin{msc}{Example}+ and \verb+\end{msc}+. The name of
+the \MSC{}, {\tt Example}, is displayed in the upper-left corner of the
+\MSC{}.
+
+The next four lines define the \emph{instances}:
+\verb+\declinst{m1}{Machine 1}{control}+ defines an instance with
+\emph{nickname} \verb+m1+ and a description consisting of two parts,
+namely, \verb+Machine 1+ and \verb+control+. The nickname is used in
+all subsequent references to this instance. The first part of the
+description is drawn above the rectangular instance head symbol, and
+the second part of the description is drawn inside the instance head
+symbol.
+
+The following lines contain the definitions of the messages. Every
+message has a source and a destination instance. The clause
+\verb+\mess{startm1}{usr}{m1}+ defines a message with name {\tt
+startm1}, which goes from instance {\tt usr} to instance {\tt m1}.
+
+In order to control the vertical placement of the messages, the \MSC{} is
+divided into levels. At every level, any number of messages may start.
+The vertical position of the end point of a message is determined
+by the optional fourth argument of the message definition, as in the
+clause \verb+\mess{output}{m2}{user}[2]+.
+This argument is the vertical offset (in number of levels) between the
+start point of the message (i.e.\ the current level) and its end point.
+If the value is 0 the message is drawn horizontally. A negative offset
+means that the arrow has an upward slope.
+
+The clause \verb+\nextlevel+ is used to advance to the next level.
+
+\section{Use of the \mscpack}
+\label{use}
+
+\subsection{The \MSC{} frame}
+\label{mscframe}
+The \verb+msc+ environment is used for making \MSC{} definitions. Thus, such a
+definition looks as follows.
+
+\begin{verbatim}
+\begin{msc}[headerpos]{mscname}
+...definition of the MSC...
+\end{msc}
+\end{verbatim}
+
+This draws the frame and the header of the \MSC{}.
+The argument \verb+mscname+ is the name of the \MSC{}.
+The header of an \MSC{} is formed from the keyword \verb+msc+, followed
+by the \verb+mscname+. Positioning of this header is controlled by
+the optional argument \verb+headerpos+. This argument can have values
+\verb+l+ (for a left aligned header), \verb+c+ (for a centered header)
+and \verb+r+ (for a right aligned header).
+The default value of \verb+headerpos+ is \verb+l+.
+
+The size of the \MSC{} frame is determined vertically by the number of levels
+occurring in the \MSC{} (see Section~\ref{levels}) and horizontally by
+the number of instances (see Section~\ref{instances}).
+
+The parameter \verb+\topnamedist+ controls the distance between the
+top of the \MSC{} frame and the header (see Section~\ref{parameters}).
+The parameter \verb+\leftnamedist+ controls the distance between the
+left of the \MSC{} frame and the header if the \verb+headerpos+ is
+\verb+l+ and it controls the distance between the right of the \MSC{}
+frame and the header if \verb+headerpos+ is \verb+r+ (see
+Section~\ref{parameters}).
+
+\subsection{Levels}
+\label{levels}
+An \MSC{} is vertically divided in {\em levels}. All events in an \MSC{} are
+attached to a certain level, or stretch out over several levels.
+Any number of events can be drawn at a certain level.
+An event will always be drawn (or started) at the current level, unless a level
+offset is specified (see e.g.\ the \verb+\mess+ command in
+Section~\ref{messages}). The level offset is an integer number, which
+denotes at which level, relative to the current level, an event should
+be drawn.
+Drawing starts at level 0.
+The following command is used to advance to the next level.
+\begin{verbatim}
+\nextlevel[leveloffset]
+\end{verbatim}
+
+The \verb+leveloffset+ is an integer value which denotes the number of
+levels to advance. By default, the value of \verb+leveloffset+ is 1,
+which means drawing continues at the next level. Setting
+\verb+leveloffset+ to a negative value may result in unexpected
+drawings, however, see the \emph{Tricks} section in the reference
+manual~\cite{BM02}.
+
+There are three parameters which control the size of the levels (see
+Section~\ref{parameters}). These are \verb+\firstlevelheight+ (the
+distance between the instance start symbol and the first level),
+\verb+\levelheight+ (the distance between two consecutive levels), and
+\verb+\lastlevelheight+ (the distance between the last level and the
+instance end symbol). Figure~\ref{parametersfig} on
+page~\pageref{parametersfig} shows all lengths of the \mscpack.
+
+\subsection{Instances}
+\label{instances}
+All instances have to be declared before they can be used. An instance
+consists of an instance head symbol with an associated name, an
+instance axis and an instance end symbol. Normal instances have a
+single line axis. Fat instances have a double line axis. The order of
+the instance declarations determines the order in which the instances
+occur in the drawing.
+
+An instance is declared with the following command.
+
+\begin{verbatim}
+\declinst(*){nickname}{instancenameabove}{instancenamewithin}
+\end{verbatim}
+
+The starred version produces a fat instance.
+The \verb+nickname+ is used for referring to this instance in the rest of the
+\MSC{} definition.
+The \verb+instancenameabove+ is put above the instance head symbol.
+The \verb+instancenamewithin+ is put inside the instance head symbol.
+
+Several parameters allow the user to customize the shape and
+positioning of instances (see Section~\ref{parameters}). These are
+\verb+\topheaddist+ (the distance between the top of the \MSC{} and the
+instance head symbol), \verb+\instheadheight+ (the height of the
+instance head symbol), \verb+\instfootheight+ (the height of the
+instance foot symbol), \verb+\bottomfootdist+ (the distance between
+the instance foot symbol and the bottom of the \MSC{} frame),
+\verb+\instwidth+ (the width of the instance head and foot symbols),
+\verb+\instdist+ (the distance between two instance axes),
+\verb+\envinstdist+ (the distance between the edge of the \MSC{} and the
+first/last instance axis), and \verb+\labeldist+ (the distance between
+the instance head symbol and the part of the instance name drawn above
+the head symbol). The command \verb+\setfootcolor{color}+ sets the
+fill color of the footer symbol. Valid color values are, e.g.,
+\texttt{black} (default), \texttt{white}, and \texttt{gray}.
+
+The following \MSC{} shows the declaration of an \MSC{} with three
+instances. The first and the last are normal instances (one line axis)
+whereas the second is a fat instance (double line axis). The second
+line, \verb+\setmscvalues{small}+, indicates that the small drawing
+style should be used (see Section~\ref{parameters}).
+
+\medskip
+
+\begin{minipage}[c]{0.4\linewidth}
+\begin{msc}[l]{instances}
+\setmscvalues{small}
+
+\declinst{i}{above}{within}
+\declinst*{j}{}{j}
+\declinst{k}{k}{}
+
+\end{msc}
+\end{minipage}
+%
+\begin{minipage}[c]{0.5\linewidth}
+{\small
+\begin{verbatim}
+\begin{msc}{instances}
+\setmscvalues{small}
+
+\declinst{i}{above}{within}
+\declinst*{j}{}{j}
+\declinst{k}{k}{}
+
+\end{msc}
+\end{verbatim}
+}
+\end{minipage}
+
+
+\subsection{Messages}
+\label{messages}
+A message is denoted by an arrow from the sending instance to the
+receiving instance. The instances are referred to by their nicknames.
+A message is defined with the following command.
+
+\begin{verbatim}
+\mess(*)[pos]{name}[labelpos]{sender}[placement]{receiver}[leveloffset]
+\end{verbatim}
+The \verb+name+ of the message may be any string. The \mscpack{}
+processes the \verb+name+ argument in LR-mode,
+see~\cite[page~36]{Lam94}. This means that the string will consist of
+one line. To generate multi-line message names, use the standard
+\cmd{parbox} command, see the \emph{Tricks} section in the reference
+manual~\cite{BM02}. By default, the name of a message label is drawn
+above the center of the arrow, but the optional parameters \verb+pos+,
+\verb+labelpos+, and \verb+placement+ influence the actual location,
+as described below. The arrow starts at the current level at the
+sending instance. The arrow ends at the current level plus the
+\verb+leveloffset+, at the receiving instance. The \verb+leveloffset+
+is an optional integer argument with default value 0. The
+\verb+sender+ and \verb+receiver+ should be the nicknames of declared
+instances.
+
+In case the sending and the receiving instance are the same, the
+message is a \emph{self message}. A self message is drawn as a
+polyline connecting the instance axis to itself.
+
+The starred version of the command, \verb+\mess*+, produces the same
+result as \verb+\mess+, except that the arrow is drawn with a dashed
+line. This can be used to draw a {\em method reply} (see~\cite{z120}).
+
+As mentioned above, placement of the message and its label is
+controlled by the optional parameters \verb+pos+, \verb+labelpos+, and
+\verb+placement+. In case of a self message, \verb+pos+ denotes the
+position of the arrow with respect to the instance axis. Valid values
+are \verb+l+ (left) and \verb+r+ (right). The default value is
+\verb+l+. In case of a non-self message, the \verb+pos+ parameter is
+ignored.
+
+Whereas the \verb+pos+ parameter defines the position of the arrow
+symbol with respect to the instance axis, the \verb+labelpos+
+parameter defines the position of the message label with
+respect to the message arrow. In case of a self message, valid values
+for \verb+labelpos+ are \verb+l+ (left) and~\verb+r+ (right). The
+default value is equal to the, possibly user defined, value of the
+\verb+pos+ parameter. In case of a non-self message, valid values for
+\verb+labelpos+ are \verb+t+ (on top) and~\verb+b+ (below). The
+default value is~\verb+t+.
+
+Finally, the \verb+placement+ parameter defines the relative distance
+of the message label to the beginning of the message. Valid values are
+real numbers in the closed interval $[0,1]$. The default value
+is~$0.5$. While drawing a message, the \mscpack{} computes the
+coordinates of the message label using \verb+placement+ and the length
+and coordinates of the arrow. It then computes a \emph{reference
+point} for the message label and places it on the coordinates just
+computed. Figures \ref{fig:refpoints} (page~\pageref{fig:refpoints})
+and~\ref{fig:refpoints:B} (page~\pageref{fig:refpoints:B})
+schematically show the reference points for message labels. In the
+first figure, the labels are located at the default position. In the
+second figure, all labels are shifted along the arrow by setting
+$\verb+placement+ = 0.9$. The \verb+\lost+ and \verb+\found+ commands
+(Section~\ref{lostfound}) and the \verb+\create+
+(Section~\ref{createstop}) command use the same method to determine
+reference points and message label locations. Note that the boxes with
+the location of the reference points are not generated by the \LaTeX{}
+code given in Figures \ref{fig:refpoints} and~\ref{fig:refpoints:B};
+we enriched the \LaTeX{} code with some extra \textsf{pstricks} code
+(see \LaTeX{} source code of this document).
+
+In addition to label position control, there are three ways to control
+the shape of messages (see Section~\ref{parameters}). These are:
+\verb+\selfmesswidth+ (a parameter to specify the width of the
+polyline used for drawing self-messages), \verb+\labeldist+ (a
+parameter to specify the distance between the label of a message and
+the message arrow), and \verb+\messarrowscale{size}+ (a command to set
+the size of the arrow head of a message). \verb+size+ should be
+positive real number.
+
+Messages to or from the environment (i.e.\ the left or the right side
+of the \MSC{} frame) can be
+specified by setting the sender or the receiver argument to one of the values
+\verb+envleft+ or \verb+envright+. (Note: Since instances and
+environments are treated equally in the implementation, at every position
+where the nickname of an instance is required, also
+\verb+envleft+ and \verb+envright+ are allowed.)
+
+The following \MSC{} shows an example of the use of messages.
+In this sample \MSC{} and the following \MSC{}s in this section we will
+not list the complete textual representations of the \MSC{}s. For brevity
+we omit the environment call and the declarations of the instances.
+Note the final \verb+\nextlevel+ command which is needed
+to make the instance axis long enough to receive message
+\verb+a+.
+
+\medskip
+
+\begin{minipage}[c]{0.4\linewidth}
+\begin{msc}{messages}
+\setmscvalues{small}
+\setlength{\topheaddist}{0.8cm}
+
+\declinst{i}{}{i}
+\declinst{j}{}{j}
+\declinst{k}{}{k}
+
+\mess{a}{j}{i}[3]
+\mess{self}{i}{i}
+\nextlevel
+\mess*{b}{j}{k}
+\mess[b]{c}{k}{envright}
+\nextlevel
+\mess{d}{k}[.6]{i}
+\nextlevel
+
+\end{msc}
+\end{minipage}
+%
+\begin{minipage}[c]{0.5\linewidth}
+{\small
+\begin{verbatim}
+\mess{a}{j}{i}[3]
+\mess{self}{i}{i}
+\nextlevel
+\mess*{b}{j}{k}
+\mess[b]{c}{k}{envright}
+\nextlevel
+\mess{d}{k}[.6]{i}
+\nextlevel
+\end{verbatim}
+}
+\end{minipage}
+
+\begin{figure}[htb]
+\begin{minipage}{\linewidth}
+\setmscvalues{small}
+\begin{multicols}{2}
+\begin{msc}{Label reference points}
+\declinst{m0}{I0}{}
+\declinst{m1}{I1}{}
+\declinst{m2}{I2}{}
+\nextlevel
+
+\mess{\rpS}{m0}{m1}
+\nextlevel
+\mess{\rpN}[b]{m1}{m2}
+\nextlevel[2]
+
+\mess{\rpS}{m1}{m0}
+\nextlevel
+\mess{\rpN}[b]{m2}{m1}
+\nextlevel[2]
+
+\mess{\rpE}{m0}{m0}[2]
+\mess[r]{\rpW}{m2}{m2}[2]
+\nextlevel[4]
+\mess{\rpW}[r]{m0}{m0}[2]
+\mess[r]{\rpE}[l]{m2}{m2}[2]
+\nextlevel[6]
+
+\mess{\rpE}{m0}{m0}[-2]
+\mess[r]{\rpW}{m2}{m2}[-2]
+\nextlevel[4]
+\mess{\rpW}[r]{m0}{m0}[-2]
+\mess[r]{\rpE}[l]{m2}{m2}[-2]
+\nextlevel[2]
+
+\mess{\rpSW}{m0}{m1}[2]
+\mess{\rpNE}[b]{m1}{m2}[2]
+\nextlevel[6]
+
+\mess{\rpSW}{m1}{m0}[-2]
+\mess{\rpNE}[b]{m2}{m1}[-2]
+\nextlevel[2]
+
+\mess{\rpSE}{m1}{m0}[2]
+\mess{\rpNW}[b]{m2}{m1}[2]
+\nextlevel[6]
+
+\mess{\rpSE}{m0}{m1}[-2]
+\mess{\rpNW}[b]{m1}{m2}[-2]
+\nextlevel[2]
+\end{msc}
+\bigskip
+
+\scriptsize
+\begin{verbatim}
+\begin{msc}{Label reference points}
+\declinst{m0}{I0}{}
+\declinst{m1}{I1}{}
+\declinst{m2}{I2}{}
+\nextlevel
+
+\mess{S}{m0}{m1}
+\nextlevel
+\mess{N}[b]{m1}{m2}
+\nextlevel[2]
+
+\mess{S}{m1}{m0}
+\nextlevel
+\mess{N}[b]{m2}{m1}
+\nextlevel[2]
+
+\mess{E}{m0}{m0}[2]
+\mess[r]{W}{m2}{m2}[2]
+\nextlevel[4]
+\mess{W}[r]{m0}{m0}[2]
+\mess[r]{E}[l]{m2}{m2}[2]
+\nextlevel[6]
+
+\mess{E}{m0}{m0}[-2]
+\mess[r]{W}{m2}{m2}[-2]
+\nextlevel[4]
+\mess{W}[r]{m0}{m0}[-2]
+\mess[r]{E}[l]{m2}{m2}[-2]
+\nextlevel[2]
+
+\mess{SW}{m0}{m1}[2]
+\mess{NE}[b]{m1}{m2}[2]
+\nextlevel[6]
+
+\mess{SW}{m1}{m0}[-2]
+\mess{NE}[b]{m2}{m1}[-2]
+\nextlevel[2]
+
+\mess{SE}{m1}{m0}[2]
+\mess{NW}[b]{m2}{m1}[2]
+\nextlevel[6]
+
+\mess{SE}{m0}{m1}[-2]
+\mess{NW}[b]{m1}{m2}[-2]
+\nextlevel[2]
+\end{msc}
+\end{verbatim}
+\end{multicols}
+\end{minipage}
+\caption{Reference points of message labels}
+\label{fig:refpoints}
+\end{figure}
+
+
+\begin{figure}[htb]
+\begin{minipage}{\linewidth}
+\setmscvalues{small}
+\begin{multicols}{2}
+\begin{msc}{Label reference points (2)}
+\declinst{m0}{I0}{}
+\declinst{m1}{I1}{}
+\declinst{m2}{I2}{}
+\nextlevel
+
+\mess{\rpS}{m0}[.9]{m1}
+\nextlevel
+\mess{\rpN}[b]{m1}[.9]{m2}
+\nextlevel[2]
+
+\mess{\rpS}{m1}[.9]{m0}
+\nextlevel
+\mess{\rpN}[b]{m2}{m1}
+\nextlevel[2]
+
+\mess{\rpE}{m0}[.9]{m0}[2]
+\mess[r]{\rpW}{m2}[.9]{m2}[2]
+\nextlevel[4]
+\mess{\rpW}[r]{m0}[.9]{m0}[2]
+\mess[r]{\rpE}[l]{m2}[.9]{m2}[2]
+\nextlevel[6]
+
+\mess{\rpE}{m0}[.9]{m0}[-2]
+\mess[r]{\rpW}{m2}[.9]{m2}[-2]
+\nextlevel[4]
+\mess{\rpW}[r]{m0}[.9]{m0}[-2]
+\mess[r]{\rpE}[l]{m2}[.9]{m2}[-2]
+\nextlevel[2]
+
+\mess{\rpSW}{m0}[.9]{m1}[2]
+\mess{\rpNE}[b]{m1}[.9]{m2}[2]
+\nextlevel[6]
+
+\mess{\rpSW}{m1}[.9]{m0}[-2]
+\mess{\rpNE}[b]{m2}[.9]{m1}[-2]
+\nextlevel[2]
+
+\mess{\rpSE}{m1}[.9]{m0}[2]
+\mess{\rpNW}[b]{m2}[.9]{m1}[2]
+\nextlevel[6]
+
+\mess{\rpSE}{m0}[.9]{m1}[-2]
+\mess{\rpNW}[b]{m1}[.9]{m2}[-2]
+\nextlevel[2]
+\end{msc}
+\bigskip
+
+\scriptsize
+\begin{verbatim}
+\begin{msc}{Label reference points (2)}
+\declinst{m0}{I0}{}
+\declinst{m1}{I1}{}
+\declinst{m2}{I2}{}
+\nextlevel
+
+\mess{S}{m0}[.9]{m1}
+\nextlevel
+\mess{N}[b]{m1}[.9]{m2}
+\nextlevel[2]
+
+\mess{S}{m1}[.9]{m0}
+\nextlevel
+\mess{N}[b]{m2}{m1}
+\nextlevel[2]
+
+\mess{E}{m0}[.9]{m0}[2]
+\mess[r]{W}{m2}[.9]{m2}[2]
+\nextlevel[4]
+\mess{W}[r]{m0}[.9]{m0}[2]
+\mess[r]{E}[l]{m2}[.9]{m2}[2]
+\nextlevel[6]
+
+\mess{E}{m0}[.9]{m0}[-2]
+\mess[r]{W}{m2}[.9]{m2}[-2]
+\nextlevel[4]
+\mess{W}[r]{m0}[.9]{m0}[-2]
+\mess[r]{E}[l]{m2}[.9]{m2}[-2]
+\nextlevel[2]
+
+\mess{SW}{m0}[.9]{m1}[2]
+\mess{NE}[b]{m1}[.9]{m2}[2]
+\nextlevel[6]
+
+\mess{SW}{m1}[.9]{m0}[-2]
+\mess{NE}[b]{m2}[.9]{m1}[-2]
+\nextlevel[2]
+
+\mess{SE}{m1}[.9]{m0}[2]
+\mess{NW}[b]{m2}[.9]{m1}[2]
+\nextlevel[6]
+
+\mess{SE}{m0}[.9]{m1}[-2]
+\mess{NW}[b]{m1}[.9]{m2}[-2]
+\nextlevel[2]
+\end{msc}
+\end{verbatim}
+\end{multicols}
+\end{minipage}
+\caption{Reference points of shifted message labels}
+\label{fig:refpoints:B}
+\end{figure}
+
+
+\subsection{Comments}
+\label{comments}
+
+Comments are additional texts to clarify (events on) an instance. The
+following command can be used to add comments to an \MSC{} diagram.
+
+\begin{verbatim}
+\msccomment[position]{text}{instname}
+\end{verbatim}
+
+The \verb|instname| parameter defines the instance to which the
+comment is attached. The text of the comment is specified by the
+\verb|text| parameter and is processed in LR-mode. The \verb|position|
+parameter defines the horizontal position of the comment relative to
+its instance. Valid values of \verb|position| are \verb|l| (left),
+\verb|r| (right), or any \LaTeX{} length. Its default value
+is~\verb|l|. If the value of \verb|position| is \verb|l|
+(or~\verb|r|), the comment will be placed \verb|\msccommentdist| units
+to the left (or right) of the \verb|instname| instance. If
+\verb|position| is a \LaTeX{} length, the comment will be placed
+\verb|position| units from the \verb|instname| instance. A negative
+length puts the comment to the left and a positive length puts the
+comment to the right of the instance.
+
+The following diagram shows how to use comments. In this diagram, the
+distance between the frame and the instances (\verb|\envinstdist|) is
+doubled in order to fit the comments inside the frame.
+
+\medskip
+\begin{minipage}[c]{0.4\linewidth}
+\setmscvalues{small}
+\begin{msc}{comments}
+\setlength{\envinstdist}{2\envinstdist}
+\declinst{i}{}{i}
+\declinst{j}{}{j}
+\mess{a}{i}{j}[2]
+\msccomment{start}{i}
+\nextlevel[2]
+\msccomment[r]{end}{j}
+\nextlevel
+\end{msc}
+\end{minipage}
+%
+\begin{minipage}[c]{0.54\linewidth}
+{\small
+\begin{verbatim}
+\setlength{\envinstdist}{2\envinstdist}
+\declinst{i}{}{i}
+\declinst{j}{}{j}
+\mess{a}{i}{j}[2]
+\msccomment{start}{i}
+\nextlevel[2]
+\msccomment[r]{end}{j}
+\nextlevel
+\end{verbatim}
+}
+\end{minipage}
+
+
+
+
+\subsection{Actions}
+\label{actions}
+An instance can perform an action, which is denoted by a rectangle.
+
+\begin{verbatim}
+\action{name}{instance}
+\end{verbatim}
+
+The action is attached at the current level to the \verb+instance+.
+The \verb+name+ is centered inside the action symbol and is processed
+in LR-mode.
+
+The following parameters determine the detailed drawing of the action
+symbol (see Section~\ref{parameters}):
+\verb+\actionwidth+ (the width of the action symbol), and
+\verb+\actionheight+ (the height of the action symbol).
+
+The next example shows that after an action often a multiple level
+increment is needed to obtain nice pictures.
+
+\medskip
+
+\begin{minipage}[c]{0.4\linewidth}
+\begin{msc}{action}
+\setmscvalues{small}
+%\setlength{\topheaddist}{0.8cm}
+
+\declinst{i}{}{i}
+\declinst{j}{}{j}
+
+\mess{a}{j}{i}
+\nextlevel
+\action{doit}{i}
+\nextlevel[2]
+\mess{b}{i}{j}
+
+\end{msc}
+\end{minipage}
+%
+\begin{minipage}[c]{0.5\linewidth}
+{\small
+\begin{verbatim}
+\mess{a}{j}{i}
+\nextlevel
+\action{doit}{i}
+\nextlevel[2]
+\mess{b}{i}{j}
+\end{verbatim}
+}
+\end{minipage}
+
+
+\subsection{Timers}
+\label{timers}
+There are five commands to draw timer events.
+\begin{verbatim}
+\settimer[placement]{name}{instance}
+\timeout[placement]{name}{instance}
+\stoptimer[placement]{name}{instance}
+\settimeout[placement]{name}{instance}[offset]
+\setstoptimer[placement]{name}{instance}[offset]
+\end{verbatim}
+
+Setting of a timer is drawn as a line connecting the \verb+instance+
+to the {\em hour glass} symbol. The \verb+name+ is put near this
+symbol. A time-out is represented by an arrow from an
+{\em hour glass} symbol to the \verb+instance+. Stopping a timer is
+drawn as a line connecting the \verb+instance+ with the timer stop
+symbol (denoted by a cross).
+The command \verb+\settimeout+ is a combination of the setting of a
+timer and a time out. The \verb+offset+ denotes the number of levels
+between the two events. The default value for \verb+offset+ is 2.
+Likewise, \verb+\setstoptimer+ is a combination
+of the setting of a timer and stopping a timer.
+
+The optional argument \verb+placement+ can have values
+\verb+l+ (meaning that the timer is drawn left of the instance axis)
+and \verb+r+ (meaning that the timer is drawn right of the instance
+axis). By default it is drawn at the left side of the instance.
+
+Several parameters can be used to control the detailed layout of timer
+symbols (see Section~\ref{parameters}):
+\verb+\timerwidth+ (the width of the hour glass and time out symbols),
+\verb+\selfmesswidth+ (the length of the arm between the symbol
+and the instance axis), and
+\verb+\labeldist+ (the distance between the name and the timersymbol).
+Furthermore, the size of the arrow head can be controlled with the
+command \verb+\messarrowscale{size}+.
+
+The various timer symbols are shown in the following example.
+
+\medskip
+
+\begin{minipage}[c]{0.4\linewidth}
+\begin{msc}{timers}
+\setmscvalues{small}
+\setlength{\topheaddist}{0.8cm}
+
+\declinst{i}{}{i}
+\declinst{j}{}{j}
+\declinst{k}{}{k}
+
+\settimer{T,50}{j}
+\setstoptimer[r]{V}{k}[6]
+\nextlevel[2]
+\timeout{T}{j}
+\settimeout{U}{i}
+\nextlevel[2]
+\settimer[r]{T,20}{j}
+\nextlevel[2]
+\stoptimer[r]{T}{j}
+
+\end{msc}
+\end{minipage}
+%
+\begin{minipage}[c]{0.5\linewidth}
+{\small
+\begin{verbatim}
+\settimer{T,50}{j}
+\setstoptimer[r]{V}{k}[6]
+\nextlevel[2]
+\timeout{T}{j}
+\settimeout{U}{i}
+\nextlevel[2]
+\settimer[r]{T,20}{j}
+\nextlevel[2]
+\stoptimer[r]{T}{j}
+\end{verbatim}
+}
+\end{minipage}
+
+\subsection{Time measurements}
+\label{measurements}
+There are several commands to add time measurements to an \MSC{}.
+
+\begin{verbatim}
+\mscmark[placement]{name}{instance}
+\measure(*)[placement]{name}{instance1}{instance2}[offset]
+\measurestart(*)[placement]{name}{instance}{gate}
+\measureend(*)[placement]{name}{instance}{gate}
+\end{verbatim}
+
+An absolute time stamp is attached to an event on an \verb+instance+
+with the command
+\verb+mscmark+. The \verb+name+ is the text attached to the mark symbol,
+which is a dashed polyline.
+The position of the mark symbol relative to the marked event is
+determined by the \verb+placement+.
+(\verb+tl+ means top-left, \verb+tr+ means top-right, \verb+ml+ means
+middle-left, \verb+mr+ means middle-right,
+\verb+bl+ means bottom-left, and \verb+br+ means bottom-right).
+
+A \verb+\measure+ connects two events from \verb+instance1+ and
+\verb+instance2+. The first event is at the current level. The second
+event is \verb+offset+ levels lower than the first event. The
+\verb+name+ is attached to the measure symbol. The measure symbol can
+be placed at the left or at the right of \verb+instance1+. This is
+controlled by the optional argument \verb+placement+, which can have
+values \verb+l+ and \verb+r+.
+
+In case the two events are far apart, the measure may be split in two
+parts. The first part is drawn with the \verb+\measurestart+ command
+and the second part with the \verb+\measureend+ command. The points
+where these two parts should be connected are drawn by a small circle,
+to which the text \verb+gate+ is attached.
+
+There are two equivalent forms of the measurement symbol. The first
+form, where the arrow heads are at the inside of the measured
+interval, is the default form. The second form, where the arrow heads
+are at the outside of the measured interval, is obtained by the
+commands \verb+\measure*+, \verb+\measurestart*+, and
+\verb+\measureend*+.
+
+
+Several parameters can be used to control the detailed layout of the
+time measurement symbols (see Section~\ref{parameters}):
+\verb+\labeldist+ (a parameter to specify the distance between the
+label of a measurement and the measurement symbol),
+\verb+\messarrowscale{size}+ (a command to set the size of the arrow
+head),
+\verb+\selfmesswidth+ (specifies the width of the measurement
+symbols).
+
+The following example illustrates marks and measurements in an \MSC{}. In
+order to include the marks inside the frame of the diagram, the
+distance between the frame and the instances (called
+\verb+\envinstdist+) is increased (before the instances are declared).
+
+\medskip
+
+\begin{minipage}[c]{0.5\linewidth}
+\begin{msc}{Time measurements}
+\setmscvalues{small}
+\setlength{\envinstdist}
+ {2\envinstdist}
+
+\declinst{i}{}{i}
+\declinst{j}{}{j}
+\declinst{k}{}{k}
+
+\mess{m1}{i}{j}[1]
+\mscmark{t=0.0}{i}
+\measure{0.6}{i}{j}[4]
+\nextlevel
+\mscmark[tr]{t=0.3}{j}
+\nextlevel[3]
+\mess{m2}{j}{k}
+\measurestart*[r]{0.2}{k}{g}
+\nextlevel[6]
+\mess{m3}{k}{i}
+\mscmark[bl]{t=1.0}{i}
+\measureend*[r]{0.2}{k}{g}
+\nextlevel
+\end{msc}
+\end{minipage}
+%
+\begin{minipage}[c]{0.44\linewidth}
+{\small
+\begin{verbatim}
+\setlength{\envinstdist}
+ {2\envinstdist}
+\declinst{i}{}{i}
+\declinst{j}{}{j}
+\declinst{k}{}{k}
+\mess{m1}{i}{j}[1]
+\mscmark{t=0.0}{i}
+\measure{0.6}{i}{j}[4]
+\nextlevel
+\mscmark[tr]{t=0.3}{j}
+\nextlevel[3]
+\mess{m2}{j}{k}
+\measurestart*[r]{0.2}{k}{g}
+\nextlevel[6]
+\mess{m3}{k}{i}
+\mscmark[bl]{t=1.0}{i}
+\measureend*[r]{0.2}{k}{g}
+\nextlevel
+\end{verbatim}
+}
+\end{minipage}
+
+
+\subsection{Lost and found messages}
+\label{lostfound}
+A lost message is denoted by an arrow starting at an instance and
+ending at a filled circle. A found message is denoted by an arrow
+starting at an open circle and ending at an instance.
+
+The following commands are used to define lost and found messages.
+\begin{verbatim}
+\lost[pos]{name}[labelpos]{gate}{instance}[placement]
+\found[pos]{name}[labelpos]{gate}{instance}[placement]
+\end{verbatim}
+
+The argument \verb+instance+ determines the instance to which the
+arrow is attached. The \verb+name+ of the message is put above the
+message arrow. The \verb+gate+ is a text associated to the circle.
+The optional arguments \verb+pos+, \verb+labelpos+, and
+\verb+placement+ have the same function as in the \verb+\mess+ command
+(Section~\ref{messages}). That is, \verb+pos+ controls the placement
+of the lost or or found message with respect to the instance
+axis. Valid values are \verb+l+ (left) and~\verb+r+ (right). The
+default value is~\verb+l+. The optional parameters \verb+labelpos+
+and \verb+placement+ control the placement of \verb+name+ with respect
+to the message arrow. Valid values for \verb+labelpos+ are \verb+t+
+(on top) and~\verb+b+ (below). The default value is~\verb+t+. Valid
+values for \verb+placement+ are real numbers in the closed interval
+$[0,1]$ and denote the relative distance of the message label
+\verb+name+ to the beginning of the arrow. The default value for
+\verb+placement+ is~$0.5$.
+
+Several parameters can be used to control the detailed layout of lost
+and found messages (see Section~\ref{parameters}):
+\verb+\lostsymbolradius+ (the radius of the circle),
+\verb+\selfmesswidth+ (the length of the arrow), and
+\verb+\labeldist+ (the distance between the name and the arrow).
+Furthermore, the size of the arrow head can be controlled with the
+command \verb+\messarrowscale{size}+.
+
+The following example shows a found and a lost message.
+
+\medskip
+
+\begin{minipage}[c]{0.4\linewidth}
+\begin{msc}{lost and found}
+\setmscvalues{small}
+\setlength{\topheaddist}{0.8cm}
+
+\declinst{i}{}{i}
+\declinst{j}{}{j}
+
+\found{m}{g}{i}
+\nextlevel
+\mess{p}{i}{j}
+\nextlevel
+\lost[r]{n}{}{j}
+
+\end{msc}
+\end{minipage}
+%
+\begin{minipage}[c]{0.5\linewidth}
+{\small
+\begin{verbatim}
+\found{m}{g}{i}
+\nextlevel
+\mess{p}{i}{j}
+\nextlevel
+\lost[r]{n}{}{j}
+\end{verbatim}
+}
+\end{minipage}
+
+
+
+\subsection{Conditions}
+\label{conditions}
+A condition is denoted by a hexagon. It is used to express that the
+system has entered a certain state. A condition relates to a number of
+instances. All conditions which take part in the condition are covered
+by the condition symbol. The other instances are drawn through the
+condition symbol.
+The following command is used to draw a condition.
+
+\begin{verbatim}
+\condition{text}{instancelist}
+\end{verbatim}
+
+The \verb+text+ is placed in the center of the condition. The
+\verb+instancelist+ expresses which instances take part in the
+condition. It is a list of nicknames of instances, separated by
+commas. Take care not to add extra white space around the nicknames,
+since this is considered part of the nickname in \LaTeX.
+The order in which the instances are listed is immaterial.
+
+There are two parameters which control the shape of the condition
+symbol (see Section~\ref{parameters}):
+\verb+\conditionheight+ (the height of the condition symbol), and
+\verb+\conditionoverlap+ (the width of the part of the condition
+symbol which extends over the rightmost/leftmost contained instance
+axis).
+
+The following example contains some conditions.
+
+\medskip
+
+\begin{minipage}[c]{0.4\linewidth}
+\begin{msc}{conditions}
+\setmscvalues{small}
+\setlength{\topheaddist}{0.8cm}
+
+\declinst{i}{}{i}
+\declinst{j}{}{j}
+\declinst{k}{}{k}
+
+\condition{some condition}{i,k}
+\nextlevel[3]
+\mess{m}{i}{j}
+\action{a}{k}
+\nextlevel
+\condition{C}{i}
+\nextlevel[2]
+\condition{A, B, C}{i,j,k}
+\nextlevel[2]
+
+\end{msc}
+\end{minipage}
+%
+\begin{minipage}[c]{0.5\linewidth}
+{\small
+\begin{verbatim}
+\condition{some condition}{i,k}
+\nextlevel[3]
+\mess{m}{i}{j}
+\action{a}{k}
+\nextlevel
+\condition{C}{i}
+\nextlevel[2]
+\condition{A, B, C}{i,j,k}
+\nextlevel[2]
+\end{verbatim}
+}
+\end{minipage}
+
+\subsection{Generalized ordering}
+\label{ordering}
+A generalized order is treated much like a regular message (see
+Section~\ref{messages}). There
+are three differences: a generalized order is drawn with a
+dotted line, it has no label, and the arrow head is in the middle of
+the line. A generalized order is defined with the following command.
+\begin{verbatim}
+\order[pos]{sender}{receiver}[leveloffset]
+\end{verbatim}
+The \verb+sender+ and \verb+receiver+ are the nicknames of the
+instances which are connected by the generalized ordering symbol.
+At the \verb+receiver+ instance, the generalized ordering symbol ends
+at the current level plus the \verb+leveloffset+. The
+\verb+leveloffset+ is an optional integer value, with default 0.
+
+In case \verb+sender+ and \verb+receiver+ denote the same instance,
+the order is a \emph{self order}. The placement of the order arrow of
+a self order is controlled by the optional argument \verb+pos+. It
+can have values \verb+l+ (meaning that the ordering symbol is drawn
+left of the instance axis) and \verb+r+ (meaning that the ordering
+symbol is drawn right of the instance axis). By default it is drawn at
+the left side of the instance. For non-self orders, the \verb+pos+
+argument is ignored.
+
+Additionally, there are two ways to control the shape
+of the generalized ordering symbol (see Section~\ref{parameters}).
+These are:
+\verb+\selfmesswidth+ (a parameter to specify the width of the polyline used for
+drawing orderings on a single instance axis).
+and
+\verb+\messarrowscale{size}+ (a command to set the size of the arrow
+head in the ordering symbol).
+
+Orderings to or from the environment (i.e.\ the left or the right side
+of the \MSC{} frame) can be
+specified by setting the sender or the receiver argument to the value
+\verb+envleft+ or \verb+envright+.
+
+An example of a generalized order is given in the following diagram.
+
+
+
+\medskip
+
+\begin{minipage}[c]{0.4\linewidth}
+\begin{msc}{generalized order}
+\setmscvalues{normal}
+\setlength{\topheaddist}{0.8cm}
+
+\declinst{i}{}{i}
+\declinst{j}{}{j}
+
+\mess{m}{envleft}{i}
+\order{i}{j}[1]
+\nextlevel
+\mess{k}{j}{envright}
+\nextlevel
+\end{msc}
+\end{minipage}
+%
+\begin{minipage}[c]{0.5\linewidth}
+{\small
+\begin{verbatim}
+\mess{m}{envleft}{i}
+\order{i}{j}[1]
+\nextlevel
+\mess{k}{j}{envright}
+\end{verbatim}
+}
+\end{minipage}
+
+
+\subsection{Instance regions}
+\label{regions}
+A part of the instance axis can be drawn in a different style. Such a
+part is called an {\em instance region}. The following
+regions are supported:
+{\em coregion} (the instance axis is dashed, which means that the order of the
+attached instances is immaterial),
+{\em suspension region} (a small rectangle with dashed left and right
+sides, which denotes that the instance is suspended),
+{\em activation region} (a small filled rectangle, which denotes that
+the instance has control).
+
+The following commands are used to draw an instance region.
+
+\begin{verbatim}
+\regionstart{type}{instname}
+\regionend{instname}
+\end{verbatim}
+
+If the \verb+\regionstart+ command is used the instance axis of
+\verb+instname+ is drawn in the shape determined by \verb+type+,
+starting from the current level. The type can have values
+\verb+coregion+, \verb+suspension+, and \verb+activation+.
+
+The shape of an instance region can be controlled with the following
+parameters (see Section~\ref{parameters}):
+\verb+\regionbarwidth+ (the width of the coregion start and end
+symbol),
+\verb+\instwidth+ (the width of the fat instance rectangle),
+\verb+\regionwidth+ (the width of the activation and suspension rectangle).
+
+In the following example, several instance regions are demonstrated.
+Notice the relative order of \verb|\mess|, \verb|\regionstart|, and
+\verb|\regionend| commands. Interchanging lines
+\verb|\regionstart{activation}{i}| and \verb|\mess{q}{j}{i}| makes the
+arrow head of the~`q' message partly invisible. Also note that the
+second activation region on~$i$ ends with a method reply
+(which is produced by the command \cmd{mess*}).
+
+\medskip
+
+\begin{minipage}[c]{0.4\linewidth}
+\begin{msc}{regions}
+\setmscvalues{small}
+\setlength{\topheaddist}{0.8cm}
+
+\declinst{i}{}{i}
+\declinst{j}{}{j}
+\declinst{k}{}{k}
+
+\regionstart{activation}{i}
+\nextlevel[3]
+\regionend{i}
+\mess{m}{i}{j}
+\nextlevel
+\regionstart{coregion}{j}
+\nextlevel
+\regionstart{suspension}{k}
+\mess{p}{j}{k}
+\nextlevel
+\regionstart{activation}{i}
+\mess{q}{j}{i}
+\nextlevel
+\regionend{j}
+\nextlevel[3]
+\regionend{i}
+\mess*{r}{i}{j}
+\nextlevel
+\mess{s}{j}{k}
+\regionend{k}
+\nextlevel
+\end{msc}
+\end{minipage}
+%
+\begin{minipage}[c]{0.5\linewidth}
+{\scriptsize
+\begin{verbatim}
+\regionstart{activation}{i}
+\nextlevel[3]
+\regionend{i}
+\mess{m}{i}{j}
+\nextlevel
+\regionstart{coregion}{j}
+\nextlevel
+\regionstart{suspension}{k}
+\mess{p}{j}{k}
+\nextlevel
+\regionstart{activation}{i}
+\mess{q}{j}{i}
+\nextlevel
+\regionend{j}
+\nextlevel[3]
+\regionend{i}
+\mess*{r}{i}{j}
+\nextlevel
+\mess{s}{j}{k}
+\regionend{k}
+\nextlevel
+\end{verbatim}
+}
+\end{minipage}
+
+In some situations, the gray-colored activation regions can hide
+message-labels. \emph{Level back-up} can help in these situations, see
+the \emph{Tricks} section in the reference manual~\cite{BM02}.
+
+\subsection{Instance creation and instance stop}
+\label{createstop}
+The \MSC{} language offers constructs for dynamic instance creation and
+instance destruction.
+An instance can dynamically create another instance by issuing a
+create command. An instance creation is drawn as a dashed message
+arrow. At the side of the arrow head, the instance head symbol for the
+created instance is drawn.
+An instance end symbol does not denote the end of the specified
+process, but merely the end of its current description. Therefore, a
+different symbol is needed which denotes that an instance stops before
+the end of the \MSC{} in which it is contained.
+The instance stop symbol is a cross.
+
+The following commands are used for instance creation and instance
+stop.
+
+\begin{verbatim}
+\dummyinst{createdinst}
+\create{name}
+ [labelpos]
+ {creator}
+ [placement]
+ {createdinst}
+ {instancenameabove}
+ {instancenamewithin}
+\stop{instance}
+\end{verbatim}
+
+In order to reserve space for an instance which will be created
+dynamically, the command \verb+dummyinst+ must be used. This command
+is mixed with the declarations of normal instances (see the
+\verb+declinst+ command, Section~\ref{instances}).
+The argument \verb+createdinst+ is the nickname of the instance that
+will be created later.
+
+An instance can be created with the \verb+\create+ command.
+This command results in a dashed horizontal message arrow labeled with
+\verb+name+. The arrow starts at the current level at the instance
+with nickname \verb+creator+ and ends at the current level at the
+instance head of the instance with nickname \verb+createdinst+. This
+instance must have been declared first with the \verb+dummyinst+
+command.
+The name of the created instance consists of two parts. The part
+called \verb+instancenameabove+ is placed above the instance head and the
+\verb+instancenamewithin+ is centered within the instance head.
+
+As with normal messages, placement of the message label is controlled
+by the optional parameters \verb+labelpos+ and \verb+placement+. That
+is, \verb+labelpos+ denotes the relative position of the message label
+with respect to the message arrow. Valid values are \verb+t+ (on top)
+and \verb+b+ (below). The default value is \verb+t+. The optional
+parameter \verb+placement+ denotes the relative distance of the
+message label with respect to the beginning of the arrow. Valid values
+are real numbers in the closed interval $[0,1]$. The default value
+is~$0.5$. See Figure~\ref{fig:refpoints}
+(page~\pageref{fig:refpoints}) and its description in
+Section~\ref{messages} for more information on the placement of
+message labels.
+
+An instance is stopped with the \verb+\stop+ command.
+The \verb+instance+ is the nickname of the stopped instance. The
+instance axis is not drawn any further below the level at which the
+\verb+\stop+ command is issued. Also, the instance foot symbol is not
+drawn.
+
+The size of the stop symbol is determined by the parameter
+\verb+\stopwidth+ (see Section~\ref{parameters}).
+The following parameters apply to the instance head symbol:
+\verb+\instheadheight+ (the height of the instance head symbol),
+\verb+\instwidth+ (the width of the instance head symbol),
+and
+\verb+\labeldist+ (the distance between the instance head symbol and
+the part of the instance name drawn above the head symbol).
+
+Take care not to specify any events on an instance which has not yet
+been created or which has already
+been stopped. This may lead to unexpected drawings.
+However, it is possible to create an instance after it has stopped,
+as showed in the next example.
+
+\medskip
+
+\begin{minipage}[c]{0.4\linewidth}
+\begin{msc}{dynamic instances}
+\setmscvalues{small}
+\setlength{\topheaddist}{0.8cm}
+
+\declinst{i}{}{i}
+\dummyinst{j}
+\declinst{k}{}{k}
+
+\mess{p}{i}{k}
+\nextlevel[3]
+\create{kick}{k}{j}{}{j}
+\nextlevel
+\stop{k}
+\nextlevel
+\mess{ok}{j}{i}
+\nextlevel
+\stop{j}
+\nextlevel[2]
+\create{start}[b]{i}[.75]{k}{}{again}
+\nextlevel[2]
+
+\end{msc}
+\end{minipage}
+%
+\begin{minipage}[c]{0.5\linewidth}
+{\small
+\begin{verbatim}
+\declinst{i}{}{i}
+\dummyinst{j}
+\declinst{k}{}{k}
+
+\mess{p}{i}{k}
+\nextlevel[3]
+\create{kick}{k}{j}{}{j}
+\nextlevel
+\stop{k}
+\nextlevel
+\mess{ok}{j}{i}
+\nextlevel
+\stop{j}
+\nextlevel[2]
+\create{start}[b]{i}[.75]{k}{}{again}
+\nextlevel[2]
+\end{verbatim}
+}
+\end{minipage}
+
+\subsection{\MSC{} references}
+\label{references}
+Within an \MSC{} a reference to other \MSC{}s can be included. Such a
+reference is drawn as a rectangle with rounded corners, covering part
+of the \MSC{}. The following commands are used to draw \MSC{} references.
+
+\begin{verbatim}
+\referencestart[lo][ro]{nickname}{text}{leftinstance}{rightinstance}
+\referenceend{nickname}
+\end{verbatim}
+
+The reference symbol starts at the level where the
+\verb+\referencestart+ command is used, and ends at the level where
+the corresponding \verb+\referenceend+ command occurs. These commands
+correspond if they have the same \verb+nickname+. The \verb+text+ is
+placed in the center of the reference symbol. The reference covers all
+instances from \verb+leftinstance+ to \verb+rightinstance+. The
+distance between the left (right) edge of the reference symbol and the
+leftmost (rightmost) covered instance axis is defined by the optional
+overlap value \verb+lo+. The default value for \verb+lo+ in large/normal/small
+\MSC{}s is 1.5/1/0.75 (see Section~\ref{parameters} for selecting
+large, normal or small drawing mode). If the second optional value
+\verb+ro+ is present too, the optional value \verb+lo+ defines the left
+overlap and the optional value \verb+ro+ defines the right overlap.
+
+The left and right edge of the reference symbol are
+\verb+nicknameleft+ and \verb+nicknameright+, where \verb+nickname+ is
+the nickname of the \MSC{} reference as defined in the
+\verb+\referencestart+ command.
+These names can be used at every place where the nickname of an
+instance is required, e.g.\ as the sender or receiver of a message.
+This is shown in the following example.
+
+\medskip
+
+\begin{minipage}[c]{0.4\linewidth}
+\begin{msc}{references}
+\setmscvalues{small}
+\setlength{\topheaddist}{0.8cm}
+
+\declinst{i}{}{i}
+\declinst{j}{}{j}
+\declinst{k}{}{k}
+
+\mess{a}{j}{k}
+\nextlevel
+\referencestart{r}{a reference}{i}{j}
+\nextlevel
+\mess{b}{rright}{k}
+\nextlevel
+\referenceend{r}
+\nextlevel
+\referencestart{p}{another reference}{i}{k}
+\nextlevel
+\mess{c}{envright}{pright}
+\nextlevel[3]
+\referenceend{p}
+
+\end{msc}
+\end{minipage}
+%
+\begin{minipage}[c]{0.55\linewidth}
+{\small
+\begin{verbatim}
+\mess{a}{j}{k}
+\nextlevel
+\referencestart{r}{a reference}{i}{j}
+\nextlevel
+\mess{b}{rright}{k}
+\nextlevel
+\referenceend{r}
+\nextlevel
+\referencestart{p}{another reference}{i}{k}
+\nextlevel
+\mess{c}{envright}{pright}
+\nextlevel[3]
+\referenceend{p}
+\end{verbatim}
+}
+\end{minipage}
+
+\subsection{Inline expressions}
+\label{inlines}
+An inline expression is a part of an \MSC{} on which an operation is
+defined. A rectangle surrounds the part of the \MSC{} containing the
+operands. The operands are separated by horizontal dashed lines.
+The operator is placed in the upper left corner of the inline
+expression symbol.
+The following commands are used to draw inline expressions.
+
+\begin{verbatim}
+\inlinestart[lo][ro]{nickname}{operator}{leftinstance}{rightinstance}
+\inlineseparator{nickname}
+\inlineend(*){nickname}
+\end{verbatim}
+
+The inline expression starts at the level where the \verb+\inlinestart+
+command occurs. The inline expression spans over the instances from
+\verb+leftinstance+ to \verb+rightinstance+. The \verb+operand+ is
+placed in the upper left corner of the rectangle. At every level where
+a corresponding \verb+\inlineseparator+ command occurs, a dashed line
+is drawn. The inline expression ends at the level where the
+\verb+\inlineend+ command occurs. The \verb+nickname+ is used to match
+corresponding commands.
+The command \verb+\inlineend*+ does the same as the command
+\verb+\inlineend+, except that the bottom line of the rectangle is
+dashed. This is used to indicate that the operand is optional.
+
+The left and right edge of the inline expression symbol are named
+\verb+nicknameleft+ and \verb+nicknameright+, where \verb+nickname+ is
+the nickname of the inline expression as defined in the
+\verb+\inlinestart+ command.
+These names can be used at every place where the nickname of an
+instance is required, e.g.\ as the sender or receiver of a message.
+
+The distance between the left (right) edge of the inline expression
+symbol and
+the leftmost (rightmost) included instance axis is defined by
+the optional overlap value \verb+lo+. The default value for
+large/normal/small \MSC{}s is
+1.5/1/0.75 (see Section~\ref{parameters} for selecting large, normal or small
+drawing mode).
+If the second optional value
+\verb+ro+ is present too, the optional value \verb+lo+ defines the left
+overlap and the optional value \verb+ro+ defines the right overlap.
+These options make it possible to easily draw nested inline expressions
+as in the following example.
+
+\medskip
+
+\begin{minipage}[c]{0.4\linewidth}
+\begin{msc}{inline expressions}
+\setmscvalues{small}
+\setlength{\topheaddist}{0.8cm}
+
+
+\declinst{i}{}{i}
+\declinst{j}{}{j}
+\declinst{k}{}{k}
+
+
+\inlinestart{exp1}{par}{i}{k}
+\nextlevel
+\mess{a}{k}{j}
+\nextlevel
+\inlinestart[0.6cm]{exp2}{alt}{i}{j}
+\nextlevel[2]
+\mess{b}{j}{i}
+\nextlevel
+\inlineseparator{exp2}
+\nextlevel
+\mess{c}{j}{i}
+\nextlevel
+\inlineend{exp2}
+\nextlevel
+\inlineseparator{exp1}
+\nextlevel
+\mess{d}{j}{k}
+\nextlevel
+\inlineend{exp1}
+\nextlevel
+\inlinestart{exp3}{opt}{i}{j}
+\nextlevel
+\mess{e}{envright}{exp3right}
+\mess{e}{exp3right}{j}
+\nextlevel
+\mess{f}{j}{i}
+\nextlevel
+\inlineend*{exp3}
+
+
+\end{msc}
+\end{minipage}
+%
+\begin{minipage}[c]{0.5\linewidth}
+{\scriptsize
+\begin{verbatim}
+\inlinestart{exp1}{par}{i}{k}
+\nextlevel
+\mess{a}{k}{j}
+\nextlevel
+\inlinestart[0.6cm]{exp2}{alt}{i}{j}
+\nextlevel[2]
+\mess{b}{j}{i}
+\nextlevel
+\inlineseparator{exp2}
+\nextlevel
+\mess{c}{j}{i}
+\nextlevel
+\inlineend{exp2}
+\nextlevel
+\inlineseparator{exp1}
+\nextlevel
+\mess{d}{j}{k}
+\nextlevel
+\inlineend{exp1}
+\nextlevel
+\inlinestart{exp3}{opt}{i}{j}
+\nextlevel
+\mess{e}{envright}{exp3right}
+\mess{e}{exp3right}{j}
+\nextlevel
+\mess{f}{j}{i}
+\nextlevel
+\inlineend*{exp3}
+\end{verbatim}
+}
+\end{minipage}
+
+\subsection{Gates}
+\label{gates}
+
+A gate determines a connection point for messages.
+
+The following command can be used to draw gates.
+
+\begin{verbatim}
+\gate(*)[hpos][vpos]{gatename}{instname}
+\end{verbatim}
+
+The unstarred version produces a normal (invisible) gate. The starred
+version produces a visible gate (a small dot). The gate is drawn at the
+current level at the instance \verb+instname+ (which can also be the
+left and right edge of e.g.\ an \MSC{} reference). The
+\verb+gatename+ is attached to the gate. The positioning of the
+\verb+gatename+ relative to the gate is determined by the values of
+\verb+hpos+ (horizontal position) and \verb+vpos+ (vertical position).
+Possible values for \verb+hpos+ are \verb+l+ (left, default) and
+\verb+right+ (right). Possible values for \verb+vpos+ are \verb+t+
+(top, default), \verb+c+ (center), and \verb+b+ (bottom).
+
+There are several parameters to control the size and shape of the
+gate symbol (see Section~\ref{parameters}). These are
+\verb+\gatesymbolradius+ (sets the radius of the gate symbol),
+\verb+\labeldist+ (the vertical distance between the gate name and
+the gate).
+
+The next example shows a number of gates.
+
+\medskip
+
+\begin{minipage}[c]{0.4\linewidth}
+\begin{msc}{gates}
+\setmscvalues{small}
+
+\declinst{i}{}{i}
+\declinst{j}{}{j}
+\declinst{k}{}{k}
+\referencestart{r}{ref}{i}{j}
+\nextlevel
+\gate{$g$}{rright}
+\mess{b}{rright}{envright}
+\gate[r][c]{$h$}{envright}
+\nextlevel
+\nextlevel
+\mess{c}{rright}{k}
+\gate*[l][b]{$h'$}{rright}
+\nextlevel[2]
+\referenceend{r}
+\end{msc}
+\end{minipage}
+%
+\begin{minipage}[c]{0.5\linewidth}
+{\footnotesize
+\begin{verbatim}
+\declinst{i}{}{i}
+\declinst{j}{}{j}
+\declinst{k}{}{k}
+\referencestart{r}{ref}{i}{j}
+\nextlevel
+\gate{$g$}{rright}
+\mess{b}{rright}{envright}
+\gate[r][c]{$h$}{envright}
+\nextlevel
+\nextlevel
+\mess{c}{rright}{k}
+\gate*[l][b]{$h'$}{rright}
+\nextlevel[2]
+\referenceend{r}
+\end{verbatim}
+}
+\end{minipage}
+
+
+\subsection{High-level \MSC{}s}
+\label{hmsc}
+A High-level \MSC{} (\HMSC{}) is a drawing which defines the relation between
+a number of \MSC{}s. It is composed of a start symbol (an upside down
+triangle), a number of end symbols (represented by triangles), a
+number of \MSC{} references (these are rectangles with rounded corners),
+a number of conditions (hexagons) and possibly several connection
+points (circles). These symbols are connected by arrows.
+
+The following commands can be used to draw \HMSC{}s.
+
+\begin{verbatim}
+\begin{hmsc}[headerpos]{hmscname}(llx,lly)(urx,ury)
+\end{hmsc}
+\hmscstartsymbol{nickname}(x,y)
+\hmscendsymbol{nickname}(x,y)
+\hmscreference{nickname}{text}(x,y)
+\hmsccondition{nickname}{text}(x,y)
+\hmscconnection{nickname}(x,y)
+\arrow{from-nickname}[coord-list]{to-nickname}
+\end{verbatim}
+
+In order to draw \HMSC{}s, a new environment is defined, which is called
+\verb+hmsc+. The command to begin this environment has several
+arguments. The argument \verb+headerpos+ is optional. It controls
+positioning of the header of the \HMSC{}. This argument can have values
+\verb+l+ (for a left aligned header), \verb+c+ (for a centered header)
+and \verb+r+ (for a right aligned header). The header of an \HMSC{} is
+formed from the keyword \verb+msc+, followed by the
+\verb+hmscname+. The size of the \HMSC{} frame is determined by the
+coordinates of the lower-left corner, \verb+(llx,lly)+, and the
+coordinates of the upper-right corner, \verb+(urx,ury)+.
+
+The \HMSC{} grid is not drawn, but used to control the positioning of the
+\HMSC{} symbols (\verb+startsymbol+, \verb+endsymbol+, \verb+reference+,
+\verb+condition+, and \verb+connection+).
+The center of each symbol is drawn on the grid point
+with coordinates \verb+{x,y}+. Each symbol also has a \verb+nickname+
+for later reference.
+
+\HMSC{} symbols can be connected by means of the \verb+arrow+ command.
+This draws an arrow from the symbol with nickname \verb+from-nickname+
+to the symbol with nickname \verb+to-nickname+. The optional argument
+\verb+coord-list+ can be used if the line connecting the source and
+the destination should not be straight. The \verb+coord-list+ has
+the following syntax: \verb+(x1,y1)(x2,y2)...(xk,yk)+. This means
+that the connecting line goes through the points with coordinates
+(x1,y1), (x2,y2), \ldots, (xk,yk).
+
+Arrows always leave the start symbol at the bottom. They enter the end symbol
+at the top.
+Arrows start and end either at the middle of the top or at the middle
+of the bottom of a reference and condition symbol. The incoming
+(outgoing) direction of the arrow determines whether it will start
+(end) at the top or at the bottom.
+
+There are several parameters to control the size and shape of the
+symbols (see Section~\ref{parameters}). These are
+\verb+\hmscconditionheight+ (the height of the condition symbol),
+\verb+\hmscconditionwidth+ (the width of the condition symbol,
+excluding the left and right angular parts),
+\verb+\hmscreferenceheight+ (the height of the reference symbol),
+\verb+\hmscreferencewidth+ (the width of the reference symbol),
+\verb+\messarrowscale{size}+ (a command to set the size of the arrow
+head of a connection line);
+\verb+setconnectiontype(type)+ (set the shape of the polyline
+connection the symbols; \verb+type+ can be \verb+straight+,
+\verb+rounded+, and \verb+curved+),
+\verb+\startsymbolwidth+ (the width of the start and end symbol),
+\verb+\topnamedist+ (sets the distance between the top of the \HMSC{} frame
+and the \HMSC{} header).
+
+An example of an \HMSC{} is in the following diagram. Notice that the
+width and height of reference symbols are changed locally (i.e.,
+between \verb+{+ and \verb+}+ braces) just before the big
+reference~\verb+b+ is defined.
+
+\medskip
+
+\noindent
+\begin{minipage}[c]{0.375\linewidth}
+
+\begin{hmsc}{High level}(-3,0)(3,12)
+\hmscstartsymbol{s}(0,10)
+\hmscreference{a}{A}(0,9)
+\hmscconnection{c}(0,7.5)
+{
+\setlength{\hmscreferencewidth}{2cm}
+\setlength{\hmscreferenceheight}{3\baselineskip}
+\hmscreference{b}{\parbox{1.9cm}
+ {\centering
+ this is a big
+ hmsc reference}
+ }(0,6)
+}
+\hmsccondition{t}{Again}(1,4.25)
+\hmsccondition{ok}{Ok}(0,3.5)
+\hmsccondition{q}{\textit{Break}}(-2,3.5)
+\hmscendsymbol{e1}(-2,2)
+\hmscreference{do}{Do it!}(0,2)
+\hmscendsymbol{e2}(0,1)
+
+\arrow{s}{a}
+\arrow{a}{c}
+\arrow{c}{b}
+\arrow{c}[(-2,7.5)]{q}
+\arrow{b}{q}
+\arrow{q}{e1}
+\arrow{b}{ok}
+\arrow{ok}{do}
+\arrow{do}{e2}
+\arrow{b}{t}
+\arrow{t}[(1,3.5)(2.5,3.5)(2.5,7.5)]{c}
+\end{hmsc}
+\end{minipage}\hfill
+\begin{minipage}[c]{0.6\linewidth}
+{\footnotesize
+\begin{verbatim}
+\begin{hmsc}{High level}(-3,0)(3,12)
+\hmscstartsymbol{s}(0,10)
+\hmscreference{a}{A}(0,9)
+\hmscconnection{c}(0,7.5)
+{\setlength{\hmscreferencewidth}{2cm}
+ \setlength{\hmscreferenceheight}
+ {3\baselineskip}
+ \hmscreference{b}{\parbox{1.9cm}
+ {\centering this is a big hmsc reference}
+ }(0,6)}
+\hmsccondition{t}{Again}(1,4.5)
+\hmsccondition{ok}{Ok}(0,3.5)
+\hmsccondition{q}{\textit{Break}}(-2,3.5)
+\hmscendsymbol{e1}(-2,2)
+\hmscreference{do}{Do it!}(0,2)
+\hmscendsymbol{e2}(0,1)
+\arrow{s}{a}
+\arrow{a}{c}
+\arrow{c}{b}
+\arrow{c}[(-2,7.5)]{q}
+\arrow{b}{q}
+\arrow{q}{e1}
+\arrow{b}{ok}
+\arrow{ok}{do}
+\arrow{do}{e2}
+\arrow{b}{t}
+\arrow{t}[(1,3.5)(2.5,3.5)(2.5,7.5)]{c}
+\end{hmsc}
+\end{verbatim}
+}
+\end{minipage}
+
+
+\subsection{\MSC{} documents}
+\label{mscdoc}
+An \MSCdoc{} is a drawing which contains various declarations
+of objects used in the \MSC{} description. For drawing \MSCdoc{}s
+he following commands are provided.
+
+\begin{verbatim}
+\begin{mscdoc}[headerpos]{mscdocname}{text}(llx,lly)(urx,ury)
+\end{mscdoc}
+\reference{text}(x,y)
+\separator{y}
+\end{verbatim}
+
+As for \MSC{} and \HMSC{}, a new environment is defined, which is named
+\verb+mscdoc+. The command to begin an \MSCdoc{} has several
+arguments. The argument \verb+headerpos+ is optional. It controls
+positioning of the header of the \MSCdoc{}.
+This argument can have values
+\verb+l+ (for a left aligned header), \verb+c+ (for a centered header)
+and \verb+r+ (for a right aligned header).
+The header of an \MSCdoc{} is formed from the keyword \verb+mscdocument+,
+followed by the \verb+mscdocname+.
+The \verb+text+ is placed left-aligned below the \MSCdoc{} header.
+The size of the \MSCdoc{} frame is determined by
+coordinates of the lower-left corner, \verb+(llx,lly)+, and the
+coordinates of the upper-right corner, \verb+(urx,ury)+.
+
+The \MSCdoc{} grid is not drawn, but used to control the positioning of the
+\MSC{} references.
+The center of such a reference is drawn on the grid point
+with coordinates \verb+{x,y}+.
+
+The \verb+separator+ command draws a dashed horizontal line. The \MSC{}
+references above the separator are the exported, while the ones below
+the separator are local.
+
+There are several parameters to control the size and shape of the
+symbols (see Section~\ref{parameters}).
+\verb+\mscdocreferenceheight+ (the height of the reference symbol),
+\verb+\mscdocreferencewidth+ (the width of the reference symbol),
+\verb+\topnamedist+ (sets the distance between the top of the \MSCdoc{}
+frame and the \MSCdoc{} header).
+
+An example of an \MSCdoc{} is in the following diagram. Notice that
+the size of references in an \MSCdoc{} had to be changed for the last
+reference.
+
+\medskip
+
+
+\begin{minipage}{0.4\linewidth}
+\begin{mscdoc}{My declarations}%
+ (0,0)(6,8)
+\reference{a}(1,6)
+\reference{b}(3,6)
+\reference{c}(1,4)
+\reference{d}(3,4)
+\separator{3}
+\setlength{\mscdocreferencewidth}{4.5\mscunit}
+\setlength{\mscdocreferenceheight}{2\baselineskip}
+\reference{%
+ \parbox{4\mscunit}%
+ {\raggedright This is a
+ two-line reference}}
+ (3,1.5)
+\end{mscdoc}
+\end{minipage}
+%
+\begin{minipage}{0.5\linewidth}
+{\small
+\begin{verbatim}
+\begin{mscdoc}{My declarations}%
+ (0,0)(6,8)
+\reference{a}(1,6)
+\reference{b}(3,6)
+\reference{c}(1,4)
+\reference{d}(3,4)
+\separator{3}
+\setlength{\mscdocreferencewidth}
+ {4.5\mscunit}
+\setlength{\mscdocreferenceheight}
+ {2\baselineskip}
+\reference{%
+ \parbox{4\mscunit}%
+ {\raggedright This is a
+ two-line reference}}
+ (3,1.5)
+\end{mscdoc}
+\end{verbatim}
+}
+\end{minipage}
+
+
+
+\section{Style parameters}
+\label{parameters}
+
+By means of a collection of parameters, the graphical appearance of
+an \MSC{} can be fine tuned to the user's taste.
+The general parameters
+are displayed in Figure~\ref{parametersfig} on page~\pageref{parametersfig}.
+
+%========================
+\begin{figure}[htb]
+\vspace{2ex} %Needed to get enough white space before the top label of
+ %the figure.
+
+\newcommand{\printlength}[1]{\mbox{\footnotesize\ttfamily \char`\\#1}}
+\begin{center}
+\setmscvalues{normal}
+\begin{msc}{Lengths}
+\psset{linewidth=.4pt,dotsep=1pt}
+\newlength{\lta}
+\newlength{\ltb}
+% \topnamedist
+\psline[linestyle=dotted](1.5cm,-\topnamedist)(2.5cm,-\topnamedist)
+\psline[arrowscale=1.3]{->}(2.5cm,.2cm)(2.5cm,0cm)
+\setlength{\lta}{\topnamedist+.2cm}
+\psline[arrowscale=1.3]{->}(2.5cm,-\lta)(2.5cm,-\topnamedist)
+\rput[tl](2.5cm,.4cm){\printlength{topnamedist}}
+
+% \leftnamedist
+\setlength{\lta}{\leftnamedist+10pt}
+\setlength{\ltb}{\topnamedist}
+\psline[linestyle=dotted,arrowscale=1.0]{->}(-10pt,-\ltb)(0,-\ltb)
+\psline[linestyle=dotted,arrowscale=1.0]{->}(\lta,-\ltb)(\leftnamedist,-\ltb)
+\psline[linestyle=dotted](\leftnamedist,10pt)(\leftnamedist,-\baselineskip)
+\rput[br](-10pt,-\ltb){\printlength{leftnamedist}}
+
+% \topheaddist
+\setlength{\lta}{\envinstdist+\instdist-.5\instwidth}
+\psline[arrowscale=1.3,linestyle=dotted]{<->}(\lta,0cm)(\lta,-\topheaddist)
+\rput[l](\lta,-.5\topheaddist){ \printlength{topheaddist}}
+
+% \bottomfootdist
+\setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\lastlevelheight+\instfootheight+\levelheight*12}
+\setlength{\lta}{\envinstdist+2\instdist-.5\instwidth}
+\rput[tl](\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(0,-\bottomfootdist)}
+\setlength{\ltb}{\ltb+.5\bottomfootdist}
+\rput[l](\lta,-\ltb){\printlength{bottomfootdist}}
+
+% \instheadheight
+\setlength{\lta}{\envinstdist+2\instdist+.5\instwidth+.2cm}
+\setlength{\ltb}{\topheaddist}
+\rput[t](\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(0,-\instheadheight)}
+\setlength{\ltb}{\ltb+.5\instheadheight}
+\rput[l](\lta,-\ltb){\printlength{instheadheight}}
+
+% \firstlevelheight
+\setlength{\lta}{\envinstdist+\instdist+.2cm}
+\setlength{\ltb}{\topheaddist+\instheadheight}
+\rput(\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,-\firstlevelheight)}
+\setlength{\ltb}{\ltb+.5\firstlevelheight}
+\rput[l](\lta,-\ltb){\printlength{firstlevelheight}}
+
+% \levelheight
+\setlength{\lta}{\envinstdist+\instdist+.2cm}
+\setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight}
+\rput[t](\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(0,-\levelheight)}
+\setlength{\ltb}{\ltb+.5\levelheight}
+\rput[l](\lta,-\ltb){\printlength{levelheight}}
+
+% \actionheight
+\setlength{\lta}{\envinstdist+2\instdist+0.5\actionwidth+.2cm}
+\setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\levelheight*7}
+\rput[t](\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(0,-\actionheight)}
+\setlength{\ltb}{\ltb+.7\actionheight}
+\rput[bl](\lta,-\ltb){\printlength{actionheight}}
+
+% \actionwidth
+\setlength{\lta}{\envinstdist+2\instdist-0.5\actionwidth}
+\setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\levelheight*7-.2cm}
+\rput(\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(\actionwidth,0)}
+\setlength{\lta}{\lta+.5\actionwidth}
+\setlength{\ltb}{\ltb-.1cm}
+\rput[bl](\lta,-\ltb){\rule{0pt}{2ex}\printlength{actionwidth}}
+
+% \conditionheight
+\setlength{\lta}{\envinstdist+2\instdist+\conditionoverlap+0.8\conditionheight}
+\setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\levelheight*10}
+\rput[t](\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(0,-\conditionheight)}
+\setlength{\ltb}{\ltb+.7\conditionheight}
+\rput[bl](\lta,-\ltb){\printlength{conditionheight}}
+
+% \inlineoverlap
+\setlength{\lta}{\envinstdist}
+\setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\levelheight*5-.2cm}
+\rput(\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(\inlineoverlap,0)}
+%\setlength{\lta}{\lta+\inlineoverlap}
+\setlength{\ltb}{\ltb-.1cm}
+\rput[bl](\lta,-\ltb){\rule{0pt}{2ex}\printlength{inlineoverlap}}
+
+% \referenceoverlap
+\setlength{\lta}{\envinstdist}
+\setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\levelheight*7-.2cm}
+\rput(\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(\referenceoverlap,0)}
+%\setlength{\lta}{\lta+\referenceoverlap}
+\setlength{\ltb}{\ltb-.1cm}
+\rput[bl](\lta,-\ltb){\rule{0pt}{2ex}\printlength{referenceoverlap}}
+
+% \conditionoverlap
+\setlength{\lta}{\envinstdist+2\instdist}
+\setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\levelheight*10-.2cm}
+\rput(\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(\conditionoverlap,0)}
+%\setlength{\lta}{\lta+\conditionoverlap}
+\setlength{\ltb}{\ltb-.1cm}
+\rput[bl](\lta,-\ltb){\rule{0pt}{2ex}\printlength{conditionoverlap}}
+
+% \lastlevelheight
+\setlength{\lta}{\envinstdist+2\instdist+.2cm}
+\setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\levelheight*12}
+\rput[t](\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(0,-\lastlevelheight)}
+%\setlength{\ltb}{\ltb+.5\lastlevelheight}
+\rput[bl](\lta,-\ltb){\printlength{lastlevelheight}}
+
+% \instfootheight
+\setlength{\lta}{\envinstdist+2\instdist+.5\instwidth+.1cm}
+\setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\levelheight*12+\lastlevelheight}
+\rput[t](\lta,-\ltb){\psline[arrowscale=1.3]{->}(0,.3cm)(0,0)}
+\setlength{\ltb}{\ltb+\instfootheight}
+\rput[t](\lta,-\ltb){\psline[arrowscale=1.3]{->}(0,-.3cm)(0,0)}
+\rput[tl](\lta,-\ltb){ \printlength{instfootheight}}
+
+% \selfmesswidth
+\setlength{\lta}{\envinstdist-\selfmesswidth}
+\setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\levelheight*2-.2cm}
+\rput(\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(\selfmesswidth,0)}
+%\setlength{\lta}{\lta+\selfmesswidth}
+\rput[r](\lta,-\ltb){\printlength{selfmesswidth}}
+
+% \regionbarwidth
+\setlength{\lta}{\envinstdist+2\instdist-.5\regionbarwidth}
+\setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\levelheight*2-.2cm}
+\rput(\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(\regionbarwidth,0)}
+\setlength{\lta}{\lta+\regionbarwidth}
+\rput[l](\lta,-\ltb){\printlength{regionbarwidth}}
+
+% \instwidth
+\setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\lastlevelheight+\instfootheight+\levelheight*12+.2cm}
+\setlength{\lta}{\envinstdist-0.5\instwidth}
+\rput(\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(\instwidth,0)}
+\rput[tl](\lta,-\ltb){\rule{0pt}{2ex}\printlength{instwidth}}
+
+% \instdist
+\setlength{\lta}{\envinstdist}
+\setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+2.5\levelheight}
+\rput[l](\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(\instdist,0)}
+\setlength{\lta}{\lta+.5\instdist}
+\setlength{\ltb}{\ltb-.1cm}
+\rput[b](\lta,-\ltb){\printlength{instdist}}
+
+% \envinstwidth
+\setlength{\lta}{0cm}
+\setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+.5\levelheight}
+\rput[l](\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(\envinstdist,0)}
+\rput[tl](\lta,-\ltb){ \printlength{envinstdist}}
+
+
+% \labeldist
+\setlength{\lta}{\envinstdist-.5\instwidth}
+\setlength{\ltb}{\topheaddist-\labeldist}
+\rput[l](\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted](-.2cm,0)(.5cm,0)}
+\rput[b](\lta,-\ltb){\psline[arrowscale=1.3]{->}(-.1cm,.3cm)(-.1cm,0)}
+\setlength{\ltb}{\topheaddist}
+\rput[l](\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted](-.2cm,0)(.5cm,0)}
+\rput[b](\lta,-\ltb){\psline[arrowscale=1.3]{->}(-.1cm,-.3cm)(-.1cm,0)}
+\rput[tr](\lta,-\ltb){\printlength{labeldist} }
+
+% \timerwidth
+\setlength{\lta}{\envinstdist-\selfmesswidth-0.5\timerwidth}
+\setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\levelheight*4+.4cm}
+\rput(\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(\timerwidth,0)}
+%\setlength{\lta}{\lta+\selfmesswidth}
+\rput[r](\lta,-\ltb){\printlength{timerwidth}}
+
+% \stopwidth
+\setlength{\lta}{\envinstdist+\instdist-0.5\stopwidth}
+\setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\levelheight*4+0.5\stopwidth+.1cm}
+\rput(\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(\stopwidth,0)}
+\setlength{\lta}{\lta+\stopwidth}
+\rput[l](\lta,-\ltb){\printlength{stopwidth}}
+
+% \lostsymbolradius
+\setlength{\lta}{\envinstdist+2\instdist+\selfmesswidth+2\lostsymbolradius+0.1cm}
+\setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\levelheight*4}
+\rput[t](\lta,-\ltb){\psline[arrowscale=1.3]{->}(0,.3cm)(0,0)}
+\setlength{\ltb}{\ltb+\lostsymbolradius}
+\rput[t](\lta,-\ltb){\psline[arrowscale=1.3]{->}(0,-.3cm)(0,0)}
+\rput[tl](\lta,-\ltb){ \printlength{lostsymbolradius}}
+
+\psset{linewidth=.8pt,dotsep=3pt}
+
+\declinst{m1}{aname}{iname}
+\declinst{st}{}{}
+\declinst{m2}{}{}
+
+\mess{msg1}{m1}{st}
+\nextlevel
+\mess{msg2}{m1}{st}
+\nextlevel
+\mess{self}{m1}{m1}
+\coregionstart{m2}
+\nextlevel
+\coregionend{m2}
+\nextlevel
+\lost[r]{x}{}{m2}
+\stop{st}
+\settimer{T}{m1}
+\nextlevel
+\inlinestart{alt}{alt}{m1}{m1}
+\nextlevel[2]
+\inlineend{alt}
+\action{a}{m2}
+\nextlevel
+\referencestart{ref}{reference}{m1}{m1}
+\nextlevel
+\referenceend{ref}
+\nextlevel
+\condition{cond1}{m1,m2}
+\nextlevel
+\nextlevel
+\mess{msg3}{m2}{m1}
+\end{msc}
+\end{center}
+
+
+\caption{User controllable parameters}
+\label{parametersfig}
+\end{figure}
+
+The value of a parameter can be changed using standard
+\LaTeX\ commands, e.g.
+\begin{verbatim}
+\setlength{\levelheight}{1cm}
+\end{verbatim}
+
+The following list describes all parameters.
+The default values for drawing \MSC{}s at large, normal and small size are
+included. See the command \verb+\setmscvalues{size}+ below for
+restoring the parameters to their original values.
+
+%========================
+\begin{defs}
+
+\item[\cmd{actionheight}]
+Height of action symbols.\\
+(\lnsvalue{0.75}{0.6}{0.5} cm.)
+
+\item[\cmd{actionwidth}]
+Width of action symbol.\\
+(\lnsvalue{1.25}{1.25}{1.2} cm.)
+
+\item[\cmd{bottomfootdist}]
+Distance between bottom of foot symbol and frame.\\
+(\lnsvalue{1.0}{0.7}{0.5} cm.)
+
+\item[\cmd{commentdist}]
+Distance between a comment and its instance.\\
+(\lnsvalue{0.5}{0.5}{0.5} cm.)
+
+\item[\cmd{conditionheight}]
+Height of condition symbols.\\
+(\lnsvalue{0.75}{0.6}{0.5} cm.)
+
+\item[\cmd{conditionoverlap}]
+Overlap of condition symbol.\\
+(\lnsvalue{0.6}{0.5}{0.4} cm.)
+
+\item[\cmd{envinstdist}]
+Distance between environments and nearest instance line.\\
+(\lnsvalue{2.5}{2.0}{1.2} cm.)
+
+\item[\cmd{firstlevelheight}] Height of level just below head
+symbols. Should not be changed inside the \MSC{} environment.\\
+(\lnsvalue{0.75}{0.6}{0.4} cm.)
+
+\item[\cmd{hmscconditionheight}]
+Height of \HMSC{} condition symbol.\\
+(\lnsvalue{0.375}{0.3}{0.25} cm.)
+
+\item[\cmd{hmscconditionwidth}]
+Width of \HMSC{} condition symbol.\\
+(\lnsvalue{1.0}{0.8}{0.7} cm.)
+
+\item[\cmd{hmscconnectionradius}]
+Radius of \HMSC{} connection symbol.\\
+(\lnsvalue{0.06}{0.05}{0.04} cm.)
+
+\item[\cmd{hmscreferenceheight}]
+Height of \HMSC{} reference symbol.\\
+(\lnsvalue{0.375}{0.3}{0.25} cm.)
+
+\item[\cmd{hmscreferencewidth}]
+Width of \HMSC{} reference symbol.\\
+(\lnsvalue{1.0}{0.8}{0.7} cm.)
+
+\item[\cmd{hmscstartsymbolwidth}]
+Width of \HMSC{} start symbol.\\
+(\lnsvalue{0.75}{0.6}{0.3} cm.)
+
+\item[\cmd{inlineoverlap}]
+Overlap of inline symbol.\\
+(\lnsvalue{1.5}{1.0}{0.75} cm.)
+
+\item[\cmd{instbarwidth}]
+Default width of vertical instance bars (applies to fat instances only).\\
+(\lnsvalue{0.0}{0.0}{0.0} cm.)
+
+\item[\cmd{instdist}]
+Distance between instance axes.\\
+(\lnsvalue{3.0}{2.2}{1.5} cm.)
+
+\item[\cmd{instfootheight}] Height of foot symbols. Should not be
+changed inside the \MSC{} environment.\\
+(\lnsvalue{0.25}{0.2}{0.15} cm.)
+
+\item[\cmd{instheadheight}] Height of head symbols. Should not be
+changed inside the \MSC{} environment.\\
+(\lnsvalue{0.6}{0.55}{0.5} cm.)
+
+\item[\cmd{instwidth}]
+Width of header and foot symbols.\\
+(\lnsvalue{1.75}{1.6}{1.2} cm.)
+
+\item[\cmd{labeldist}]
+Distance between labels and the symbols to which they belong (for instance, message labels and arrows).\\
+(\lnsvalue{1.0}{1.0}{1.0} ex.)
+
+\item[\cmd{lastlevelheight}] Height of level just above foot
+symbols. Should not be changed inside the \MSC{} environment.\\
+(\lnsvalue{0.5}{0.4}{0.3} cm.)
+
+\item[\cmd{leftnamedist}] Distance between left of the frame and
+(left of) \MSC, \HMSC, or \MSCdoc{} title.\\
+(\lnsvalue{0.3}{0.2}{0.1} cm.)
+
+\item[\cmd{levelheight}]
+Height of a level.\\
+(\lnsvalue{0.75}{0.5}{0.4} cm.)
+
+\item[\cmd{lostsymbolradius}]
+Radius of the lost and found symbols.\\
+(\lnsvalue{0.15}{0.12}{0.08} cm.)
+
+\item[\cmd{markdist}]
+Horizontal distance from a mark to its instance.\\
+(\lnsvalue{1.0}{1.0}{1.0} cm.)
+
+\item[\cmd{measuredist}]
+Horizontal distance from a measure to its (closest) instance.\\
+(\lnsvalue{1.0}{1.0}{1.0} cm.)
+
+\item[\cmd{measuresymbolwidth}]
+Width of a measure symbol.\\
+(\lnsvalue{0.75}{0.6}{0.4} cm.)
+
+\item[\cmd{mscdocreferenceheight}]
+Height of reference symbol in an \MSCdoc.\\
+(\lnsvalue{0.375}{0.3}{0.25} cm.)
+
+\item[\cmd{mscdocreferencewidth}]
+Width of reference symbol in an \MSCdoc.\\
+(\lnsvalue{1.0}{0.8}{0.7} cm.)
+
+\item[\cmd{referenceoverlap}]
+Overlap of reference symbol.\\
+(\lnsvalue{1.5}{1.0}{0.75} cm.)
+
+\item[\cmd{regionbarwidth}]
+Width of region bars.\\
+(\lnsvalue{0.5}{0.4}{0.2} cm.)
+
+\item[\cmd{selfmesswidth}]
+Length of horizontal arms of self messages.\\
+(\lnsvalue{0.75}{0.6}{0.4} cm.)
+
+\item[\cmd{stopwidth}]
+Width of the stop symbol.\\
+(\lnsvalue{0.6}{0.5}{0.3} cm.)
+
+\item[\cmd{timerwidth}]
+Width of the \emph{timer} symbols.\\
+(\lnsvalue{0.4}{0.3}{0.2} cm.)
+
+\item[\cmd{topheaddist}]
+Distance between top of head symbols and frame.\\
+(\lnsvalue{1.5}{1.3}{1.2} cm.)
+
+\item[\cmd{topnamedist}] Distance between top of the frame and
+(top of) \MSC, \HMSC, or \MSCdoc{} title.\\
+(\lnsvalue{0.3}{0.2}{0.2} cm.)
+
+\end{defs}
+
+In addition there are several commands which allow the user to adjust
+the \MSC{} drawing to his own taste.
+
+\begin{defs}
+
+\item[\cmd{messarrowscale}\{\emph{scalefactor}\}] Sets the scale
+factor (a positive real number) of message arrow
+heads. (\lnsvalue{2}{1.5}{1.2})
+
+\item[\cmd{setmscscale}\{\emph{scalefactor}\}] Sets the scale factor
+of the \MSC{} environment to \emph{scalefactor}. the scale factor is
+supposed to be a real number. Scaling is done when the \MSC{}
+environment ends (\verb|\end{msc}|). The default of \emph{scalefactor}
+is~1. A more consistent way for
+varying the size of the \MSC{} can be obtained by using the
+\verb+\setmesvalues+ command as described below.
+(default value 1.)
+
+\item[\cmd{psset}\{\texttt{linewidth=D}\}] This command sets the width
+of all lines in \MSC{}s, \HMSC{}s, and \MSCdoc{}s to length \verb+D+. If
+this command is issued outside the msc environment, then the value is
+set for the complete document. If it is used directly after the start
+of the msc environment it only holds for this \MSC{}.\\
+(large/normal/small value 0.8/0.7/0.6 pt.)
+
+\item[\cmd{setfootcolor}\{\emph{color}\}] Sets the color of the foot
+symbols of \MSC{} instances. Possible values are \emph{black},
+\emph{white}, \emph{gray}, or \emph{lightgray}. For more color values,
+see the documentation of the \LaTeXe{} \textsf{color} package.
+
+\end{defs}
+
+The following command can be used to set the above mentioned
+style parameters to suitable values.
+
+\begin{defs}
+\item[\cmd{setmscvalues}\{\emph{size}\}] Sets all parameters of the \mscpack{} to
+ predefined values. Valid values for \emph{size} are:
+\verb|small|, \verb|normal|, and \verb|large|.
+(The default value of \verb+size+ is \verb+normal+.
+This can be used for drawings with at maximum six instances on a
+sheet of A4 paper.
+For sizes \verb+large+ and \verb+small+, a maximum of four and nine
+instances respectively fit on a sheet of A4 paper.)
+\end{defs}
+
+Caution has to be taken when changing the value of a parameter within
+the \MSC{} definition. The following parameters can be changed within an
+\MSC{} definition without unexpected side effects:
+
+\begin{flushleft}
+\verb+\actionheight+,
+\verb+\actionwidth+,
+\verb+\bottomfootdist+,
+\verb+\conditionheight+,
+\verb+\conditionoverlap+,
+\verb+\inlineoverlap+,
+\verb+\instfootheight+,
+\verb+\instwidth+ (however, this may cause different sizes of
+corresponding instance header and footer symbols),
+\verb+\labeldist+,
+\verb+\lastlevelheight+,
+\verb+\levelheight+,
+\verb+\lostsymbolradius+,
+\verb+\referenceoverlap+,
+\verb+\regionbarwidth+,
+\verb+\selfmesswidth+,
+\verb+\stopwidth+,
+\verb+\timerwidth+, and
+\verb+\topnamedist+.
+\end{flushleft}
+
+
+In addition to the parameters specific to the \mscpack,
+standard \LaTeX\ commands can be used to change the type style and
+other details.
+For example, if the command \verb+\sffamily+ is included directly after
+the start of the msc environment, the text in the \MSC{}
+is drawn using a {\sf sans serif} font. Likewise, the text size can be
+changed by inserting, e.g., the command \verb+\small+.
+The \verb+\raisebox+ and \verb+\parbox+ commands
+can also be used to position and format names.
+
+
+\section{Example}
+\label{example}
+Figure~\ref{ex} on page~\pageref{ex} shows the \MSC{} defined in the
+following \LaTeX\ fragment.
+
+{\small
+\begin{verbatim}
+\begin{msc}{Example}
+\declinst{usr}{The user}{User}
+\declinst{m1}{Control}{M1}
+\dummyinst{m2}
+\declinst{m3}{Another Machine}{M3}
+
+\create{start}{m1}{m2}{Processing}{M2}
+\mess{msg 0}{envleft}{usr}
+\mess{msg 1}{envright}{m2}[1]
+\nextlevel
+
+\mess{msg 2}{usr}{m1}
+\order{m1}{m2}[4]
+\action{a}{m3}
+
+\nextlevel
+\found{msg x}{}{usr}
+\nextlevel
+
+\mess{msg 3}{usr}{m2}[-1]
+\coregionstart{m1}
+\settimeout{S}{m3}[2]
+\nextlevel
+
+
+\mess{msg 4}{m1}{usr}
+\coregionstart{m2}
+\settimer[r]{T}{m3}
+\nextlevel
+
+\mess[r]{msg 5}{m2}{m2}[3]
+\mess{msg 6}{usr}{usr}[2]
+\nextlevel
+
+\mess{msg 7}{m2}{usr}
+\timeout[r]{T}{m3}
+\nextlevel
+
+\coregionend{m2}
+\nextlevel
+
+\coregionend{m1}
+\stoptimer[r]{T'}{m3}
+\nextlevel
+
+\lost[r]{msg y}{Mach 1}{usr}
+\mess{msg 8}{m1}{envright}
+\nextlevel
+
+\condition{condition 1}{usr,m2}
+\setstoptimer[r]{U}{m3}
+\nextlevel[2]
+\stop{usr}
+
+\end{msc}
+\end{verbatim}
+}
+
+\begin{figure}[htb]
+\begin{center}
+\begin{msc}{Example}
+\declinst{usr}{The user}{User}
+\declinst{m1}{Control}{M1}
+\dummyinst{m2}
+\declinst{m3}{Another Machine}{M3}
+
+\create{start}{m1}{m2}{Processing}{M2}
+\mess{msg 0}{envleft}{usr}
+\mess{msg 1}{envright}{m2}[1]
+\nextlevel
+
+\mess{msg 2}{usr}{m1}
+\order{m1}{m2}[4]
+\action{a}{m3}
+
+\nextlevel
+\found{msg x}{}{usr}
+\nextlevel
+
+\mess{msg 3}{usr}{m2}[-1]
+\coregionstart{m1}
+\settimeout{S}{m3}[2]
+\nextlevel
+
+
+\mess{msg 4}{m1}{usr}
+\coregionstart{m2}
+\settimer[r]{T}{m3}
+\nextlevel
+
+\mess[r]{msg 5}{m2}{m2}[3]
+\mess{msg 6}{usr}{usr}[2]
+\nextlevel
+
+\mess{msg 7}{m2}{usr}
+\timeout[r]{T}{m3}
+\nextlevel
+
+\coregionend{m2}
+\nextlevel
+
+\coregionend{m1}
+\stoptimer[r]{T'}{m3}
+\nextlevel
+
+\lost[r]{msg y}{Mach 1}{usr}
+\mess{msg 8}{m1}{envright}
+\nextlevel
+
+\condition{condition 1}{usr,m2}
+\setstoptimer[r]{U}{m3}
+\nextlevel[2]
+\stop{usr}
+
+\end{msc}
+
+\caption{A menagerie of \MSC{} symbols}
+\label{ex}
+\end{center}
+\end{figure}
+
+
+\section{Acknowledgments}
+Thanks are due to the following people for providing us with useful
+input: Peter Peters, Michel Reniers. In addition, we
+thank the people who have submitted bugs, and sometimes even
+bug-fixes. These people are mentioned in the \emph{Maintenance}
+document of the \mscpack{} (Section~3, \emph{Bugs}).
+
+\bibliographystyle{plain}
+\bibliography{biblio}
+
+\end{document}
diff --git a/Master/texmf-dist/doc/latex/msc/refman.tex b/Master/texmf-dist/doc/latex/msc/refman.tex
new file mode 100644
index 00000000000..a4c416a4b6c
--- /dev/null
+++ b/Master/texmf-dist/doc/latex/msc/refman.tex
@@ -0,0 +1,1672 @@
+% file: refman.tex
+% Copyright 2002 V. Bos and S. Mauw
+% This file is part of the MSC Macro Package.
+%
+% RCS version: $Id: refman.tex,v 1.7 2002/07/01 10:38:59 vbos Exp $
+%
+\documentclass[a4paper]{article}
+\usepackage{a4wide}
+
+\usepackage{multicol}
+\usepackage{msc}
+
+\newlength{\rpwidth}
+\setlength{\rpwidth}{.5cm}
+\newlength{\rpheight}
+\setlength{\rpheight}{0.5\levelheight}
+\newcommand{\rpN}{%
+ \psframe(-0.5\rpwidth,-\rpheight)(0.5\rpwidth,0\rpheight)%
+ \rput[B](0\rpwidth,-0.8\rpheight){\footnotesize \textsc{n}}%
+ \pscircle[fillstyle=solid,fillcolor=black](0\rpwidth,0\rpheight){.5\labeldist}%
+}
+\newcommand{\rpNE}{%
+ \psframe(-\rpwidth,-\rpheight)(0\rpwidth,0\rpheight)%
+ \rput[B](-.5\rpwidth,-0.8\rpheight){\footnotesize \textsc{ne}}%
+ \pscircle[fillstyle=solid,fillcolor=black](0\rpwidth,0\rpheight){.5\labeldist}%
+}
+\newcommand{\rpE}{%
+ \psframe(-\rpwidth,-.5\rpheight)(0\rpwidth,.5\rpheight)%
+ \rput[B](-.5\rpwidth,-0.3\rpheight){\footnotesize \textsc{e}}%
+ \pscircle[fillstyle=solid,fillcolor=black](0\rpwidth,0\rpheight){.5\labeldist}%
+}
+\newcommand{\rpSE}{%
+ \psframe(-\rpwidth,0\rpheight)(0\rpwidth,\rpheight)%
+ \rput[B](-.5\rpwidth,0.2\rpheight){\footnotesize \textsc{se}}%
+ \pscircle[fillstyle=solid,fillcolor=black](0\rpwidth,0\rpheight){.5\labeldist}%
+}
+\newcommand{\rpS}{%
+ \psframe(-.5\rpwidth,\rpheight)(.5\rpwidth,0\rpheight)%
+ \rput[t](0\rpwidth,0.8\rpheight){\footnotesize \textsc{s}}%
+ \pscircle[fillstyle=solid,fillcolor=black](0\rpwidth,0\rpheight){.5\labeldist}%
+}
+\newcommand{\rpSW}{%
+ \psframe(0\rpwidth,0\rpheight)(\rpwidth,\rpheight)%
+ \rput[B](.5\rpwidth,0.2\rpheight){\footnotesize \textsc{sw}}%
+ \pscircle[fillstyle=solid,fillcolor=black](0\rpwidth,0\rpheight){.5\labeldist}%
+}
+\newcommand{\rpW}{%
+ \psframe(0\rpwidth,-.5\rpheight)(\rpwidth,.5\rpheight)%
+ \rput[B](.5\rpwidth,-0.3\rpheight){\footnotesize \textsc{w}}%
+ \pscircle[fillstyle=solid,fillcolor=black](0\rpwidth,0\rpheight){.5\labeldist}%
+}
+\newcommand{\rpNW}{%
+ \psframe(0\rpwidth,-\rpheight)(\rpwidth,0\rpheight)%
+ \rput[B](.5\rpwidth,-0.8\rpheight){\footnotesize \textsc{nw}}%
+ \pscircle[fillstyle=solid,fillcolor=black](0\rpwidth,0\rpheight){.5\labeldist}%
+}
+
+
+
+% The following code is taken from the doc package. It defines a global
+% macro \bslash that produces a bslash (if present in the current font).
+\makeatletter
+{\catcode`\|=\z@ \catcode`\\=12 |gdef|bslash{\}}
+\makeatother
+\newcommand{\cmd}[1]{\texttt{\bslash #1}}
+
+\usepackage{url}
+\newcommand{\acro}[1]{{\scshape\lowercase{#1}}}
+
+\newcommand\MSC{\acro{MSC}}
+\newcommand\HMSC{\acro{HMSC}}
+\newcommand{\MSCdoc}{\MSC{}doc}
+\newcommand{\mscpack}{\MSC{} macro package}
+
+\newcommand{\env}[1]{\texttt{#1}}
+\newcommand{\opt}[1]{[#1]}
+\newcommand{\cmdarg}[1]{\{\emph{#1}\}}
+\newcommand{\coordarg}[1]{\emph{#1}}
+\newcommand{\coordargs}[2]{(\coordarg{#1},\coordarg{#2})}
+\newcommand{\lnsvalue}[3]{large/normal/small value #1/#2/#3}
+
+\newenvironment{defs}{%
+ \begin{list}{}%
+ {\setlength{\labelwidth}{0pt}%
+ \setlength{\labelsep}{1em}%
+ \setlength{\leftmargin}{1em}%
+ \setlength{\parsep}{1ex}%
+ \setlength{\listparindent}{0pt}%
+ \setlength{\rightmargin}{0pt}%
+ \renewcommand{\makelabel}[1]{##1}%
+ \raggedright%
+ }%
+ }{%
+ \end{list}}
+
+\title{
+ A \LaTeX\ macro package for Message Sequence Charts\\{\large Reference Manual}
+}
+
+\author{
+ \begin{tabular}{cc}
+ Victor Bos & Sjouke Mauw\\
+ \footnotesize Turku Centre for Computer Science &
+ \footnotesize Eindhoven University of Technology \\ [-0.8ex]
+ \footnotesize Software Construction Laboratory &
+ \footnotesize Department of Mathematics and Computing Science \\ [-0.8ex]
+ \footnotesize Lemmink\"aisenkatu 14 &
+ \footnotesize P.O.\ Box 513 \\ [-0.8ex]
+ \footnotesize FIN--20520 Turku &
+ \footnotesize NL--5600 MB Eindhoven \\ [-0.8ex]
+ \footnotesize Finland &
+ \footnotesize The Netherlands \\
+ \footnotesize \texttt{vbos@abo.fi} &
+ \footnotesize \texttt{sjouke@win.tue.nl}
+ \end{tabular}
+}
+
+\date{\small Version \mscversion, last update \today\\
+ Describing \mscpack{} version \mscversion}
+
+
+
+\begin{document}
+\maketitle
+
+\tableofcontents
+
+\section{Introduction}
+
+The \mscpack{} was developed to draw (actually, to write)
+\emph{Message Sequence Charts} (\MSC{}s) with \LaTeX. The current
+version supports most of the \MSC{} language standardized
+in~\cite{z120}. The manual~\cite{BM02a} describes how to use the
+\mscpack{} and is illustrated with numerous examples. This reference manual
+briefly describes the main concepts of the package and it provides
+lists of all available environments and commands. In addition, it
+lists both the user-definable lengths and the internal lengths that
+are used by the package to compute the layout of \MSC{}s.
+\section{Concepts}
+
+The \mscpack{} offers three different kinds
+of diagrams:
+
+\begin{itemize}
+\item \MSC{} diagrams (normal \MSC{}s)
+\item \HMSC{} diagrams (high level \MSC{}s)
+\item \MSCdoc{} diagrams (\MSC{} documents)
+\end{itemize}
+For each of these diagrams, the package provides a \LaTeX{}
+environment. Figure~\ref{fig:types:of:diagrams} shows an example of
+each diagram. The source code for these diagrams is given in
+Figure~\ref{fig:sources}. Depending on the environment, different
+\mscpack{} commands can be used. Furthermore, since each environment
+is implemented as a \texttt{pspicture} (see \textsf{pstricks}
+documentation), it is possible to use \textsf{pstricks} commands
+inside the \MSC{} environments.
+
+\begin{figure}
+\begin{center}
+\setmscvalues{small}
+\begin{tabular}{ccc}
+\begin{msc}%
+ {Example 1}%
+\declinst{i}{$i$}{}
+\declinst{j}{$j$}{}
+\nextlevel
+\mess{a}{i}{j}
+\nextlevel[2]
+\mess{b}{j}{i}
+\nextlevel
+\end{msc}%
+%
+&
+\begin{hmsc}%
+ {Example 2}%
+ (0,0)(4,4.65)
+\hmscstartsymbol{S}(2,3.75)
+\hmscconnection{c}(2,3.25)
+\hmscreference{R1}{A}(2,2.5)
+\hmsccondition{C}{?}(2,1.5)
+\hmscendsymbol{E}(1.5,0.5)
+\arrow{S}{c}
+\arrow{c}{R1}
+\arrow{R1}{C}
+\arrow{C}
+ [(2.5,1)(3,1)(3,3.25)]
+ {c}
+\arrow{C}[(1.5,1)]{E}
+\end{hmsc}%
+&
+\begin{mscdoc}%
+ {Example 3}%
+ (0,0)(4,4.65)
+\reference{A}(1,3.0)
+\reference{B}(3,3.0 )
+\separator{2.0}
+\reference{C}(2,1.0)
+\end{mscdoc}%
+\\
+(a) \MSC{} diagram &
+(b) \HMSC{} diagram &
+(c) \MSCdoc{} diagram
+\end{tabular}
+\end{center}
+
+\caption{Examples of different diagrams}
+\label{fig:types:of:diagrams}
+\end{figure}
+
+\begin{figure}[htb]
+\hrulefill
+\begin{center}
+\begin{minipage}[t]{0.3\linewidth}
+\small
+\begin{verbatim}
+\begin{msc}%
+ {Example 1}
+\declinst{i}{$i$}{}
+\declinst{j}{$j$}{}
+\nextlevel
+\mess{a}{i}{j}
+\nextlevel[2]
+\mess{b}{j}{i}
+\nextlevel
+\end{msc}
+\end{verbatim}
+\end{minipage}
+\hfil
+\begin{minipage}[t]{0.3\linewidth}
+\small
+\begin{verbatim}
+\begin{hmsc}%
+ {Example 2}%
+ (0,0)(4,4.65)
+\hmscstartsymbol{S}(2,3.75)
+\hmscconnection{c}(2,3.25)
+\hmscreference{R1}{A}(2,2.5)
+\hmsccondition{C}{?}(2,1.5)
+\hmscendsymbol{E}(1.5,0.5)
+\arrow{S}{c}
+\arrow{c}{R1}
+\arrow{R1}{C}
+\arrow{C}
+ [(2.5,1)(3,1)(3,3.25)]
+ {c}
+\arrow{C}[(1.5,1)]{E}
+\end{hmsc}
+\end{verbatim}
+\end{minipage}
+\hfil
+\begin{minipage}[t]{0.3\linewidth}
+\small
+\begin{verbatim}
+\begin{mscdoc}%
+ {Example 3}%
+ (0,0)(4,4.65)
+\reference{A}(1,3.0)
+\reference{B}(3,3.0 )
+\separator{2.0}
+\reference{C}(2,1.0)
+\end{mscdoc}
+\end{verbatim}
+\end{minipage}
+\end{center}
+\hrulefill
+\caption{Source code for diagrams of Figure~\ref{fig:types:of:diagrams}}
+\label{fig:sources}
+\end{figure}
+
+
+The \MSC{} environment provides most functionality of the package. The
+following concepts should help in understanding the user-commands of
+this environment.
+
+
+\begin{defs}
+\item[\emph{current height}] The \emph{current height} of an \MSC{} is a
+length that indicates the y-postion relative to the top of the msc
+frame. The \MSC{} drawing commands use this y-position to draw msc
+symbols, e.g., instance heads, messages, actions, and instance
+feet. The internal length \verb|\msc@currentheight| is the current
+height. This variables is changed whenever the command
+\verb|\nextlevel| is invoked.
+
+\item[\emph{current width}] The \emph{current width} of an \MSC{} is the
+distance from the left side of the \MSC{} frame to the right side of the
+\MSC{} frame. As such, it depends on the lengths \verb|\envinstdist| and
+\verb|\instdist| as well as on the number of instances. The internal
+length \verb|\msc@currentwidth| is the current width. During
+construction of an msc, that is, in between \verb|\begin{msc}| and
+\verb|\end{msc}|, \verb|\msc@currentwidth| is equal to
+$\verb|\envinstdist| + (n \times \verb|instdist|)$, provided that~$n$ is
+the number of instances defined so far (see \verb|\mscinstcnt| in the
+section \emph{Internal counters} below) and the length
+\verb|\instdist| is not changed between instances. At the end of an
+\MSC{} construction, an additional \verb|\envinstdist| is added to
+\verb|\msc@currentwidth|. The \verb|\msc@currentwidth| determines the
+x-position of new \MSC{} instances.
+
+\item[\emph{level}] A level is a horizontal layer in an \MSC{} which is
+used to construct msc's in a top-down fashion. Each level is
+\verb|\levelheight| units high and spans the complete width of the
+msc. The first level starts at $\verb|\topheaddist| +
+\verb|\instheadheight| + \verb|\firstlevelheight|$ units below the top
+of the \MSC{} frame. The \verb|\nextlevel| commands advances the \MSC{} to
+the next (lower) level.
+
+\item[\emph{\MSC{} instance}] The main building blocks of MSC diagrams
+are \emph{instances}. Instances are represented by vertical
+bars. \emph{Fat} instances are represented by two vertical
+lines. Usually, an instance has both a head symbol and a foot symbol.
+In the \mscpack, each \MSC{} instance has a \emph{nickname} by which
+the instance is identified. In the \mscpack{} there are special
+instances:
+
+\begin{itemize}
+
+\item The left environment (nickname \verb|envleft|).
+
+\item The right environment (nickname \verb|envright|).
+
+\item The left side of an inline expression. If the nickname of the
+inline expression is \verb|nm|, the nickname of the left side is
+\verb|nmleft|.
+
+\item The right side of an inline expression. If the nickname of the
+inline expression is \verb|nm|, the nickname of the left side is
+\verb|nmright|.
+
+\item The left side of an reference expression. If the nickname of the
+reference expression is \verb|nm|, the nickname of the left side is
+\verb|nmleft|.
+
+\item The right side of an reference expression. If the nickname of the
+reference expression is \verb|nm|, the nickname of the left side is
+\verb|nmright|.
+
+\item A \emph{dummy} instance is an instance that is invisible; it
+reserves space needed to draw an instance. It is useful to create
+(see \verb|create| command) instances with create-messages.
+
+\end{itemize}
+
+\item[\emph{nickname}] A nickname is a unique identification of an
+\emph{instance}.
+
+\item[\emph{message label reference points}] In order to place a
+message label somewhere near the message arrow, the \mscpack{}
+computes a \emph{reference point} for each message label. This is a
+location on the bounding box of the label such that the distance
+between the arrow and the reference point is minimized. Figures
+\ref{fig:refpoints} (page~\pageref{fig:refpoints})
+and~\ref{fig:refpoints:B} (page~\pageref{fig:refpoints:B}) show the
+location of reference points for all possible locations of message
+labels. Note that the boxes with the location of the reference points
+are not generated by the \LaTeX{} code given in these figures; we
+enriched the \LaTeX{} code with some extra \textsf{pstricks} code (see
+\LaTeX{} source code of this document).
+
+\end{defs}
+
+\begin{figure}[!htb]
+\begin{minipage}{\linewidth}
+\setmscvalues{small}
+\begin{multicols}{2}
+\begin{msc}{Label reference points}
+\declinst{m0}{I0}{}
+\declinst{m1}{I1}{}
+\declinst{m2}{I2}{}
+\nextlevel
+
+\mess{\rpS}{m0}{m1}
+\nextlevel
+\mess{\rpN}[b]{m1}{m2}
+\nextlevel[2]
+
+\mess{\rpS}{m1}{m0}
+\nextlevel
+\mess{\rpN}[b]{m2}{m1}
+\nextlevel[2]
+
+\mess{\rpE}{m0}{m0}[2]
+\mess[r]{\rpW}{m2}{m2}[2]
+\nextlevel[4]
+\mess{\rpW}[r]{m0}{m0}[2]
+\mess[r]{\rpE}[l]{m2}{m2}[2]
+\nextlevel[6]
+
+\mess{\rpE}{m0}{m0}[-2]
+\mess[r]{\rpW}{m2}{m2}[-2]
+\nextlevel[4]
+\mess{\rpW}[r]{m0}{m0}[-2]
+\mess[r]{\rpE}[l]{m2}{m2}[-2]
+\nextlevel[2]
+
+\mess{\rpSW}{m0}{m1}[2]
+\mess{\rpNE}[b]{m1}{m2}[2]
+\nextlevel[6]
+
+\mess{\rpSW}{m1}{m0}[-2]
+\mess{\rpNE}[b]{m2}{m1}[-2]
+\nextlevel[2]
+
+\mess{\rpSE}{m1}{m0}[2]
+\mess{\rpNW}[b]{m2}{m1}[2]
+\nextlevel[6]
+
+\mess{\rpSE}{m0}{m1}[-2]
+\mess{\rpNW}[b]{m1}{m2}[-2]
+\nextlevel[2]
+\end{msc}
+\bigskip
+
+\footnotesize
+\begin{verbatim}
+\begin{msc}{Label reference points}
+\declinst{m0}{I0}{}
+\declinst{m1}{I1}{}
+\declinst{m2}{I2}{}
+\nextlevel
+
+\mess{S}{m0}{m1}
+\nextlevel
+\mess{N}[b]{m1}{m2}
+\nextlevel[2]
+
+\mess{S}{m1}{m0}
+\nextlevel
+\mess{N}[b]{m2}{m1}
+\nextlevel[2]
+
+\mess{E}{m0}{m0}[2]
+\mess[r]{W}{m2}{m2}[2]
+\nextlevel[4]
+\mess{W}[r]{m0}{m0}[2]
+\mess[r]{E}[l]{m2}{m2}[2]
+\nextlevel[6]
+
+\mess{E}{m0}{m0}[-2]
+\mess[r]{W}{m2}{m2}[-2]
+\nextlevel[4]
+\mess{W}[r]{m0}{m0}[-2]
+\mess[r]{E}[l]{m2}{m2}[-2]
+\nextlevel[2]
+
+\mess{SW}{m0}{m1}[2]
+\mess{NE}[b]{m1}{m2}[2]
+\nextlevel[6]
+
+\mess{SW}{m1}{m0}[-2]
+\mess{NE}[b]{m2}{m1}[-2]
+\nextlevel[2]
+
+\mess{SE}{m1}{m0}[2]
+\mess{NW}[b]{m2}{m1}[2]
+\nextlevel[6]
+
+\mess{SE}{m0}{m1}[-2]
+\mess{NW}[b]{m1}{m2}[-2]
+\nextlevel[2]
+\end{msc}
+\end{verbatim}
+\end{multicols}
+\end{minipage}
+\caption{Reference points of message labels}
+\label{fig:refpoints}
+\end{figure}
+
+
+\begin{figure}[!htb]
+\begin{minipage}{\linewidth}
+\setmscvalues{small}
+\begin{multicols}{2}
+\begin{msc}{Label reference points (2)}
+\declinst{m0}{I0}{}
+\declinst{m1}{I1}{}
+\declinst{m2}{I2}{}
+\nextlevel
+
+\mess{\rpS}{m0}[.9]{m1}
+\nextlevel
+\mess{\rpN}[b]{m1}[.9]{m2}
+\nextlevel[2]
+
+\mess{\rpS}{m1}[.9]{m0}
+\nextlevel
+\mess{\rpN}[b]{m2}{m1}
+\nextlevel[2]
+
+\mess{\rpE}{m0}[.9]{m0}[2]
+\mess[r]{\rpW}{m2}[.9]{m2}[2]
+\nextlevel[4]
+\mess{\rpW}[r]{m0}[.9]{m0}[2]
+\mess[r]{\rpE}[l]{m2}[.9]{m2}[2]
+\nextlevel[6]
+
+\mess{\rpE}{m0}[.9]{m0}[-2]
+\mess[r]{\rpW}{m2}[.9]{m2}[-2]
+\nextlevel[4]
+\mess{\rpW}[r]{m0}[.9]{m0}[-2]
+\mess[r]{\rpE}[l]{m2}[.9]{m2}[-2]
+\nextlevel[2]
+
+\mess{\rpSW}{m0}[.9]{m1}[2]
+\mess{\rpNE}[b]{m1}[.9]{m2}[2]
+\nextlevel[6]
+
+\mess{\rpSW}{m1}[.9]{m0}[-2]
+\mess{\rpNE}[b]{m2}[.9]{m1}[-2]
+\nextlevel[2]
+
+\mess{\rpSE}{m1}[.9]{m0}[2]
+\mess{\rpNW}[b]{m2}[.9]{m1}[2]
+\nextlevel[6]
+
+\mess{\rpSE}{m0}[.9]{m1}[-2]
+\mess{\rpNW}[b]{m1}[.9]{m2}[-2]
+\nextlevel[2]
+\end{msc}
+\bigskip
+
+\footnotesize
+\begin{verbatim}
+\begin{msc}{Label reference points (2)}
+\declinst{m0}{I0}{}
+\declinst{m1}{I1}{}
+\declinst{m2}{I2}{}
+\nextlevel
+
+\mess{S}{m0}[.9]{m1}
+\nextlevel
+\mess{N}[b]{m1}[.9]{m2}
+\nextlevel[2]
+
+\mess{S}{m1}[.9]{m0}
+\nextlevel
+\mess{N}[b]{m2}{m1}
+\nextlevel[2]
+
+\mess{E}{m0}[.9]{m0}[2]
+\mess[r]{W}{m2}[.9]{m2}[2]
+\nextlevel[4]
+\mess{W}[r]{m0}[.9]{m0}[2]
+\mess[r]{E}[l]{m2}[.9]{m2}[2]
+\nextlevel[6]
+
+\mess{E}{m0}[.9]{m0}[-2]
+\mess[r]{W}{m2}[.9]{m2}[-2]
+\nextlevel[4]
+\mess{W}[r]{m0}[.9]{m0}[-2]
+\mess[r]{E}[l]{m2}[.9]{m2}[-2]
+\nextlevel[2]
+
+\mess{SW}{m0}[.9]{m1}[2]
+\mess{NE}[b]{m1}[.9]{m2}[2]
+\nextlevel[6]
+
+\mess{SW}{m1}[.9]{m0}[-2]
+\mess{NE}[b]{m2}[.9]{m1}[-2]
+\nextlevel[2]
+
+\mess{SE}{m1}[.9]{m0}[2]
+\mess{NW}[b]{m2}[.9]{m1}[2]
+\nextlevel[6]
+
+\mess{SE}{m0}[.9]{m1}[-2]
+\mess{NW}[b]{m1}[.9]{m2}[-2]
+\nextlevel[2]
+\end{msc}
+\end{verbatim}
+\end{multicols}
+\end{minipage}
+\caption{Reference points of shifted message labels}
+\label{fig:refpoints:B}
+\end{figure}
+
+
+\section{Environments}
+
+\begin{defs}
+
+\item[\cmd{begin}\texttt{\{msc\}}\opt{titlepos}\{\emph{title}\}\texttt{...\cmd{end}\{msc\}}]
+The environment to draw msc's. The parameter \emph{title} defines the
+title of the msc. The optional parameter \emph{titlepos} defines the
+position of the title relative to the frame of the msc. Valid
+positions are \verb|l|~(left), \verb|c|~(center), and
+\verb|r|~(right). The default position is~\verb|l|.
+
+\item[\cmd{begin}\texttt{\{hmsc\}}\opt{titlepos}\{\emph{title}\}\texttt{...\cmd{end}\{hmsc\}}\coordargs{llx}{lly}\coordargs{urx}{ury}]
+The environment to draw \HMSC's. The parameter \emph{title} defines the
+title of the \HMSC. The optional parameter \emph{titlepos} defines the
+position of the title relative to the frame of the \HMSC. Valid
+positions are \verb|l|~(left), \verb|c|~(center), and
+\verb|r|~(right). The default position is~\verb|l|. The size of the
+\HMSC{} is determined by two pairs of coordinates. The coordinates
+\coordargs{llx}{lly} define the lower left corner of the \HMSC. The
+coordinates \coordargs{urx}{ury} define the upper right corner of the
+\HMSC.
+
+\item[\cmd{begin}\texttt{\{mscdoc\}}\opt{titlepos}\{\emph{title}\}\texttt{...\cmd{end}\{mscdoc\}}\coordargs{llx}{lly}\coordargs{urx}{ury}]
+The environment to draw \MSCdoc{} documents. The parameter
+\emph{title} defines the title of the \MSCdoc{} document. The optional
+parameter \emph{titlepos} defines the position of the title relative
+to the frame of the \MSCdoc{} document. Valid positions are \verb|l|~(left),
+\verb|c|~(center), and \verb|r|~(right). The default position
+is~\verb|l|. The size of the \MSCdoc{} is determined by two pairs of
+coordinates. The coordinates \coordargs{llx}{lly} define the lower
+left corner of the \MSCdoc. The coordinates \coordargs{urx}{ury}
+define the upper right corner of the \MSCdoc.
+
+
+\end{defs}
+
+
+\section{Commands}
+
+\begin{defs}
+
+\item[\cmd{action}\{\emph{txt}\}\{\emph{nm}\}] Draws an \emph{action}
+symbol on the instance with nickname \emph{nm}. The parameter \emph{txt}
+defines the name of the action. The size of the action symbol is
+controlled by the \verb|\actionheight| and \verb|\actionwidth|
+lengths.
+
+\item[\cmd{arrow}\cmdarg{nm0}\opt{\coordargs{xpos${}_1$}{ypos${}_1$}$\ldots$\coordargs{xpos${}_n$}{ypos${}_n$}}\cmdarg{nm1}]
+Draws an arrow in an \HMSC{} diagram. The arrow starts at the symbol
+with nickname~\emph{nm0} and ends at the symbol with
+nickname~\emph{nm1}. The optional parameter
+\coordargs{xpos${}_1$}{ypos${}_1$}$\ldots$\coordargs{xpos${}_n$}{ypos${}_n$}
+is a list of intermediate points the arrow should pass through.
+
+\item[\cmd{changeinstbarwidth}\{\emph{nm}\}\{\emph{wd}\}] Changes the
+bar width of instance \emph{nm} to \emph{wd}. The parameter \emph{wd}
+should be a valid \LaTeX{} length.
+
+\item[\cmd{comment}\opt{\emph{pos}}\{\emph{txt}\}\{\emph{nm}\}] Puts a
+comment at instance \emph{nm}. The parameter \emph{txt} is the
+comment. The optional parameter \emph{pos} defines the horizontal
+position of the comment relative to instance \emph{nm}. Valid
+positions are \verb|l|~(left), \verb|r|~(right), and all valid
+lengths. If the position is \verb|l| or~\verb|r|, the comment will be
+put at \verb|\msccommentdist| units to the left or right, respectively, from
+the instance axis. If \emph{pos} is a length, the comment will be put
+\emph{pos} units from the instance axis. A negative \emph{pos} puts the
+comment to the left and a positive \emph{pos} puts it to the right of
+the instance axis.
+
+\item[\cmd{condition}\{\emph{txt}\}\{\emph{instancelist}\}] Draws a
+\emph{condition} symbol on the instances occurring in
+\emph{instancelist}. The parameter \emph{txt} defines the text to be
+placed in the \emph{condition} symbol. The parameter
+\emph{instancelist} is a comma separated list of instance
+nicknames. Note that there should be no white space between the commas
+and the nicknames; only if a nickname contains white space is a white
+space allowed in \emph{instancelist}.
+
+\item[\cmd{coregionend}\{\emph{nm}\}] Ends the co-region on the instance
+\emph{nm}. This command is obsolete (see \verb|\regionend|).
+
+\item[\cmd{coregionstart}\{\emph{nm}\}] Starts a co-region on the instance
+\emph{nm}. This command is obsolete (see \verb|\regionstart|).
+
+\item[\cmd{create}\{\emph{msg}\}\opt{\emph{labelpos}}\{\emph{creator}\}\opt{\emph{placement}}\{\emph{nm}\}\{\emph{na}\}\{\emph{in}\}]
+Instance with nickname \emph{creator} sends a create message with
+label \emph{msg} to instance \emph{nm}. Instance \emph{nm} should be a
+dummy (invisible) instance at the time of the create message, see
+\cmd{dummyinst}. The head symbol of \emph{nm} is drawn at
+\verb|\msc@currentheight|. The parameter \emph{an} (above name) is put
+above the head symbol. The parameter \emph{in} (inside name) is put
+inside the head symbol. \emph{nm}'s y-position is set to
+\verb|\msc@currentheight| $+$ \verb|\instheadheight|. The optional
+parameter \emph{labelpos} defines the position of the message label. Valid
+values are \verb|t| and~\verb|b|, denoting a label position on top of
+the arrow and a label position below the arrow, respectively. The
+optional parameter \emph{placement} defines the relative position of
+the message label along the message arrow. Valid values are real
+numbers in the closed interval $[0,1]$, where~$0$ corresponds to the
+beginning of the arrow and~$1$ corresponds to the end of the
+arrow. The default value is~$0.5$.
+
+\item[\cmd{declinst(*)}\{\emph{nm}\}\{\emph{an}\}\{\emph{in}\}]
+Defines an instance with nickname \emph{nm}. The starred version
+makes a \emph{fat instance}. The x-position is \verb|\instdist| to the
+right of \verb|\msc@currentwidth|. The head symbol of the instance is
+drawn at \verb|\msc@currentheight|. The parameter \emph{an} (above
+name) is put above the head symbol. The parameter \emph{in} (inside
+name) is put inside the head symbol. The
+instance y-position is set to \verb|\msc@currentheight| $+$ \verb|\instheadheight|.
+
+
+\item[\cmd{drawframe}\{\emph{str}\}] A command to turn on/off the
+drawing of the frame around msc's, hmsc's, and mscdoc's. If \emph{str}
+is `yes', the frame will be drawn, otherwise the frame will not be
+drawn.
+
+\item[\cmd{drawinstfoot}\{\emph{str}\}] A command to turn on/off
+drawing of instance foot symbols. If \emph{str} is `yes', the foot
+symbols will be drawn, otherwise they will not be drawn.
+
+\item[\cmd{drawinsthead}\{\emph{str}\}] A command to turn on/off
+drawing of instance head symbols. If \emph{str} is `yes', the head
+symbols will be drawn, otherwise they will not be drawn.
+
+\item[\cmd{dummyinst(*)}\{\emph{nm}\}] Defines a \emph{dummy instance}
+with nickname \emph{nm}. The starred version makes a \emph{fat
+instance}. The x-position is \verb|\instdist| to the right of
+\verb|\msc@currentwidth|. No head symbol is drawn. The
+instance y-position is undefined.
+
+\item[\cmd{found}\opt{\emph{pos}}\{\emph{label}\}\opt{\emph{labelpos}}\{\emph{gate}\}\{\emph{nm}\}\opt{\emph{placement}}]
+Draws a \emph{found message} to instance \emph{nm}. The \emph{label}
+parameter defines the message name. The \emph{gate} parameter defines
+the gate name. The optional parameter \emph{pos} defines the position
+of the message relative to instance \emph{nm}. Valid positions are
+\verb|l| (left) and \verb|r| (right). The default position is
+\verb|l|. The optional parameter \emph{labelpos} defines the position
+of the message label with respect to the arrow. Valid values are
+\verb+t+ (on top) and \verb+b+ (below). The default value is \verb+t+.
+The optional parameter \emph{placement} defines the relative position
+of the message label along the message arrow. Valid values are real
+numbers in the closed interval $[0,1]$, where~$0$ corresponds to the
+beginning of the arrow and~$1$ corresponds to the end of the
+arrow. The default value is~$0.5$. The length of the arrow is
+determined by \verb+\selfmesswidth+.
+
+\item[\cmd{gate(*)}\opt{\emph{hpos}}\opt{\emph{vpos}}\{\emph{txt}\}\{\emph{nm}\}]
+Draws a gate at instance \emph{nm}. The parameter \emph{txt} defines
+the name of the gate. The starred version produces a visible gate by
+drawing a black circle at instance \emph{nm}. The unstarred version
+produces an invisible gate. The position of the parameter \emph{txt}
+is controlled by the optional parameters \emph{hpos} and \emph{vpos}:
+\emph{hpos} defines the horizontal position relative to instance
+\emph{nm} and \emph{vpos} defines the vertical position relative to
+the current height (\verb|\msc@currentheight|). Valid horizontal
+positions are \verb|l|~(left) and \verb|r|~(right). The default
+horizontal position is~\verb|l|. Valid vertical positions are
+\verb|t|~(top), \verb|c|~(center), and \verb|b|~(bottom). The default
+vertical is~\verb|t|.
+
+\item[\cmd{hmsccondition}\cmdarg{nm}\cmdarg{txt}\coordargs{xpos}{ypos}]
+Draws an \HMSC{} condition symbol with nickname \emph{nm} at position
+\coordargs{xpos}{ypos}. The \emph{txt} parameter is placed inside the
+condition symbol.
+
+\item[\cmd{hmscconnection(*)}\cmdarg{nm}\coordargs{xpos}{ypos}] Draws
+an \HMSC{} connection symbol with nickname \emph{nm} at position
+\coordargs{xpos}{ypos}. The unstarred version produces an invisible
+connection symbol. The starred version produces a visible connection
+symbol (i.e., a small circle).
+
+\item[\cmd{hmscendsymol}\cmdarg{nm}\coordargs{xpos}{ypos}] Draws an
+\HMSC{} end symbol with nickname \emph{nm} at position
+\coordargs{xpos}{ypos}.
+
+\item[\cmd{hmsckeyword}] The \HMSC{} keyword. The default value is `hmsc'.
+
+\item[\cmd{hmsckeywordstyle}\{\emph{kw}\}] A one-parameter command to
+typeset the \HMSC{} keyword. The command can expect \verb|\hmsckeyword| to
+be the value of \emph{kw}. The default `value' is \verb|\textbf|.
+
+\item[\cmd{hmscreference}\cmdarg{nm}\cmdarg{txt}\coordargs{xpos}{ypos}]
+Draws an \HMSC{} reference symbol with nickname \emph{nm} at position
+\coordargs{xpos}{ypos}. The \emph{txt} parameter is placed inside the
+condition symbol.
+
+\item[\cmd{hmscstartsymbol}\cmdarg{nm}\coordargs{xpos}{ypos}]
+\HMSC{} start symbol with nickname \emph{nm} at position
+\coordargs{xpos}{ypos}.
+
+\item[\cmd{inlineend(*)}\{\emph{nm}\}] Ends the matching inline
+expression (matching means equal nicknames). The unstarred version
+draws a solid line to close the inline expression. The starred version
+draws a dashed line to close the inline expression.
+
+\item[\cmd{inlineseparator}\{\emph{nm}\}] Draws an inline separator
+line at the inline expression with nickname \emph{nm}. The separator
+is drawn at \verb|\msc@currentheight|.
+
+\item[\cmd{inlinestart}\opt{\emph{lo}}\opt{\emph{ro}}\{\emph{nm}\}\{\emph{txt}\}\{\emph{fi}\}\{\emph{li}\}]
+Defines an \emph{inline expression} with nickname \emph{nm}. The
+inline expression is started at \verb|\msc@currentheight| and
+continues until the level where a matching \cmd{inlineend} command is
+found (matching means equal nicknames). The \emph{txt} parameter
+defines the text of the inline expression. The first instance of the
+inline expression is \emph{fi}. The last instance of the inline
+expression is \emph{li}. The optional parameter \emph{lo} defines the
+left and right overlap of the inline expression. If the second
+optional parameter, \emph{ro}, is present, \emph{lo} defines the left
+and \emph{ro} defines the right overlap.
+
+\item[\cmd{inststart}\{\emph{nm}\}\{\emph{an}\}\{\emph{in}\}] Starts
+instance with nickname \emph{nm}. Instance \emph{nm} should be a dummy
+(invisible) instance at the time of the \cmd{inststart} command, see
+\cmd{dummyinst}. The head symbol is drawn at
+\verb|\msc@currentheight|. The parameter \emph{an} (above name) is put
+above the head symbol. The parameter \emph{in} (inside name) is put
+inside the head symbol. The instance y-position is set to
+\verb|\msc@currentheight| $+$ \verb|\instheadheight|.
+
+\item[\cmd{inststop}\{\emph{nm}\}] Stops instance with nickname
+\emph{nm}. The foot symbol is drawn at \verb|\msc@currentheight|. The
+instance y-position is undefined after this command.
+
+\item[\cmd{lost}\opt{\emph{pos}}\{\emph{label}\}\opt{\emph{labelpos}}\{\emph{gate}\}\{\emph{nm}\}\opt{\emph{placement}}]
+Draws a \emph{lost message} from instance \emph{nm}. The \emph{label}
+parameter defines the message name. The \emph{gate} parameter defines
+the gate name. The optional parameter \emph{pos} defines the position
+of the message relative to instance \emph{nm}. Valid positions are
+\verb|l| (left) and \verb|r| (right). The default position is
+\verb|l|. The optional parameter \emph{labelpos} defines the position
+of the message label with respect to the arrow. Valid values are
+\verb+t+ (on top) and \verb+b+ (below). The default value is \verb+t+.
+The optional parameter \emph{placement} defines the relative position
+of the message label along the message arrow. Valid values are real
+numbers in the closed interval $[0,1]$, where~$0$ corresponds to the
+beginning of the arrow and~$1$ corresponds to the end of the
+arrow. The default value is~$0.5$. The length of the arrow is
+determined by \verb+\selfmesswidth+.
+
+\item[\cmd{measure(*)}\opt{\emph{pos}}\{\emph{txt}\}\{\emph{nm1}\}\{\emph{nm2}\}\opt{\emph{offset}}]
+Puts a \emph{measure} at instances \emph{nm1} and \emph{nm2}. The
+parameter \emph{txt} defines the label of the measure. The starred
+version puts the triangular measure symbols outside the measure; the
+unstarred version puts the triangular measure symbols inside the
+measure. The optional \emph{pos} parameter defines the horizontal
+position of the measure relative to instances \emph{nm1}
+and~\emph{nm2}. Valid positions are \verb|l|~(left), \verb|r|~(right),
+and all valid lengths. If the position is \verb|l| or~\verb|r|, the
+measure will be put at \verb|\measuredist| units to the left or right,
+respectively, from the closest instance axis. If \emph{pos} is a
+length, the measure will be put \emph{pos} units from the closest
+instance axis. A negative \emph{pos} puts the measure to the left and
+a positive \emph{pos} puts it to the right of the instances. The
+optional parameter \emph{offset} defines the number of levels the
+measure should extend vertically. The default value for \emph{offset}
+is~1.
+
+
+\item[\cmd{measureend(*)}\opt{\emph{pos}}\{\emph{txt}\}\{\emph{nm}\}\{\emph{gate}\}]
+Puts a \emph{measure end} symbol at instance \emph{nm}.The starred
+version puts the triangular measure symbol outside the measure; the
+unstarred version puts the triangular measure symbol inside the
+measure. The \emph{txt} parameter defines the label of the
+measure. The \emph{gate} parameter defines the name of the gate of the
+measure end symbol. The optional \emph{pos} parameter defines the
+horizontal position of the measure relative to the
+\emph{nm} instance. Valid positions are \verb|l|~(left), \verb|r|~(right), and
+all valid lengths. If the position is \verb|l| or~\verb|r|, the
+measure will be put at \verb|\measuredist| units to the left or right,
+respectively, from the instance axis. If \emph{pos} is a length, the
+measure will be put \emph{pos} units from the instance axis. A
+negative \emph{pos} puts the measure to the left and a positive
+\emph{pos} puts it to the right of the instance.
+
+\item[\cmd{measurestart(*)}\opt{\emph{pos}}\{\emph{txt}\}\{\emph{nm}\}\{\emph{gate}\}]
+Puts a \emph{measure start} symbol at instance \emph{nm}.The starred
+version puts the triangular measure symbol outside the measure; the
+unstarred version puts the triangular measure symbol inside the
+measure. The \emph{txt} parameter defines the label of the
+measure. The \emph{gate} parameter defines the name of the gate of the
+measure start symbol. The optional parameter \emph{pos} defines the
+horizontal position of the measure relative to instance
+\emph{nm}. Valid positions are \verb|l|~(left), \verb|r|~(right), and
+all valid lengths. If the position is \verb|l| or~\verb|r|, the
+measure will be put at \verb|\measuredist| units to the left or right,
+respectively, from the instance axis. If \emph{pos} is a length, the
+measure will be put \emph{pos} units from the instance axis. A
+negative \emph{pos} puts the measure to the left and a positive
+\emph{pos} puts it to the right of the instance.
+
+\item[\cmd{mess(*)}\opt{\emph{pos}}\{\emph{label}\}\opt{\emph{labelpos}}\{\emph{sender}\}\opt{\emph{placement}}\{\emph{receiver}\}\opt{\emph{offset}}]
+Draws a message from \emph{sender} instance to \emph{receiver}
+instance. The starred version draws a dashed line arrow, instead of a
+solid arrow. This can be used to distinguish method calls from method
+replies. The \emph{sender} and \emph{receiver} may be the same
+instance, in which case the message is a \emph{self message}. The
+parameter \emph{label} defines the message name. The message starting
+y-position is \verb|\msc@currentheight| and the ending y-position of
+the message is defined by \verb|\msc@currentheight| $+$
+$(\textit{offset}\ \times $ \verb|\levelheight|$)$. The optional
+parameter \emph{pos} defines the position of self messages with
+respect to the instance axis. Valid values are \verb+l+ (left) and
+\verb+r+ (right). The default value is \verb+l+. The optional
+parameter \emph{labelpos} defines the position of the message
+label. In case of a self message, valid values are \verb|l| and
+\verb|r|, denoting a label position left from the arrow and right from
+the arrow, respectively. For self-messages the default value of
+\verb+labelpos+ is the value of \verb+pos+. In case of a non-self
+message, valid values are \verb|t| (default) and \verb|b|, denoting a
+label position on top of the message arrow and below the message
+arrow, respectively. The optional parameter \emph{placement} defines
+the relative position of the message label along the message
+arrow. Valid values are real numbers in the closed interval $[0,1]$,
+where~$0$ corresponds to the beginning of the arrow and~$1$
+corresponds to the end of the arrow. The default value is~$0.5$. The
+default value of the optional parameter \emph{offset} is~0 for normal
+messages and~1 for self messages.
+
+\item[\cmd{messarrowscale}\{\emph{scalefactor}\}] Sets the scale
+factor (a real number) of message arrow heads. The default value
+is~1.5
+
+\item[\cmd{mscdate}] The date of the \mscpack.
+
+
+\item[\cmd{mscdockeyword}] The \MSCdoc{} keyword. The default value is `mscdoc'.
+
+\item[\cmd{mscdockeywordstyle}\{\emph{kw}\}] A one-parameter command to
+typeset the mscdoc keyword. The command can expect \verb|\mscdockeyword| to
+be the value of \emph{kw}. The default `value' is \verb|\textbf|.
+
+
+
+\item[\cmd{msckeyword}] The \MSC{} keyword. The default value is `msc'.
+
+\item[\cmd{msckeywordstyle}\{\emph{kw}\}] A one-parameter command to
+typeset the \MSC{} keyword. The command can expect \verb|\msckeyword| to
+be the value of \emph{kw}. The default `value' is \verb|\textbf|.
+
+\item[\cmd{mscmark}\opt{\emph{pos}}\{\emph{txt}\}\{\emph{nm}\}] Puts a
+mark at instance \emph{nm}. The parameter \emph{txt} is the name of
+the mark. The optional parameter \emph{pos} defines the horizontal and
+vertical position of the mark relative to instance \emph{nm} and the
+current height \verb|\msc@currentheight|. Valid positions are
+\verb|tl|~(top-left), \verb|tr|~(top-right), \verb|bl|~(bottom-left),
+and \verb|br|~(bottom-right). The default position is \verb|tl|. The
+horizontal distance between the mark and the instance is defined by
+\verb+\markdist+.
+
+\item[\cmd{mscunit}] A string denoting the (default) unit of all
+lengths used by the \mscpack. Valid values are \emph{cm},
+\emph{em}, \emph{ex}, \emph{in}, \emph{mm}, \emph{pt}, etc. The
+default value is~\emph{cm}.
+
+\item[\cmd{setmscunit}\{\emph{unit}\}] Changes the value of
+\cmd{mscunit} into \emph{unit}. Valid values for \emph{unit} are
+\emph{cm}, \emph{em}, \emph{ex}, \emph{in}, \emph{mm}, \emph{pt}, etc.
+
+\item[\cmd{mscversion}] The version number of the \mscpack.
+
+\item[\cmd{nextlevel}\opt{\emph{offset}}] Increases the number of
+levels by the value of the optional parameter \emph{offset}. The
+default value of \emph{offset} is~1. Increasing the level number means
+that \verb|\msc@currentheight| is increased by $\textit{offset} \times
+\verb|\levelheight|$. The first time this macro is used, the actual
+increase of \verb|\msc@currentheight| is $\verb|\firstlevelheight| +
+((\textit{offset} - 1) \times \verb|\levelheight|)$. Negative values
+of \emph{offset} back up a number of levels. There are situations
+where this is useful, see Section~\ref{sec:tricks}.
+
+\item[\cmd{nogrid}] Turns off grid drawing in \MSC, \HMSC, and
+\MSCdoc{} diagrams. This command should not be used inside an \MSC,
+\HMSC, or \MSCdoc{} evironment.
+
+\item[\cmd{order}\opt{\emph{pos}}\{\emph{sender}\}\{\emph{receiver}\}\opt{\emph{offset}}]
+Draws an \emph{order line} from the \emph{sender} instance to the
+\emph{receiver} instance. The \emph{sender} and \emph{receiver} may be
+the same instance, in which case the order is a \emph{self-order}. The
+order starting y-position is \verb|\msc@currentheight| and the ending
+y-position of the order is defined by \verb|\msc@currentheight| $+$
+$(\textit{offset}\ \times $ \verb|\levelheight|$)$. In case of a
+self-order, the optional parameter \emph{pos} defines the position of
+the order relative to the \emph{sender} instance. Valid positions are
+\verb|l| (left) and \verb|r| (right). The default position is
+\verb|l|. In case of a non-self-order, the \emph{pos} parameter is
+ignored. The default value of the optional parameter \emph{offset}
+is~0 for normal orders and~1 for self orders.
+
+\item[\cmd{reference}\cmdarg{txt}\coordargs{xpos}{ypos}] Draws an
+\MSCdoc{} reference symbol. The \emph{txt} parameter defines the text to
+be placed inside the \MSCdoc{} reference symbol. The coordinates
+\coordargs{xpos}{ypos} define the position of the reference symbol.
+
+\item[\cmd{referenceend}\{\emph{nm}\}] Ends the reference expression with
+nickname \emph{nm}.
+
+\item[\cmd{referencestart}\opt{\emph{lo}}\opt{\emph{ro}}\{\emph{nm}\}\{\emph{txt}\}\{\emph{fi}\}\{\emph{li}\}]
+Defines a \emph{reference expression} with nickname \emph{nm}. The
+reference expression is started at \verb|\msc@currentheight| and
+continues until the level where a matching \verb|\referenceend| command
+is found. The \emph{txt} parameter defines the text of the reference
+expression. The first instance of the reference expression is
+\emph{fi}. The last instance of the reference expression is
+\emph{li}. The optional parameter \emph{lo} defines the left and right
+overlap of the reference expression. If the second optional parameter,
+\emph{ro}, is present, \emph{lo} defines the left and \emph{ro}
+defines the right overlap.
+
+\item[\cmd{regionend}\{\emph{nm}\}] Ends the current region on
+instance \emph{nm}. The region style of the instance \emph{nm} is
+reset to \emph{normal} again. Note: this command makes
+\verb|\coregionend| obsolete.
+
+\item[\cmd{regionstart}\{\emph{rstyle}\}\{\emph{nm}\}] Starts a region
+on the instance \emph{nm}. The style of the region is defined by the
+\emph{rstyle} parameter. Valid region styles are \emph{coregion},
+\emph{suspension}, \emph{activation}, and \emph{normal}. Note: this
+command makes \verb|\coregionstart| obsolete.
+
+\item[\cmd{separator}\cmdarg{ypos}] Draws a separator in an \MSCdoc{}
+diagram. The \coordarg{ypos} parameter defines the vertical position of the
+separator in the \MSCdoc{} diagram.
+
+\item[\cmd{setfootcolor}\{\emph{color}\}] Sets the color of the foot symbols of
+\MSC{} instances. Possible values are \emph{black}, \emph{white},
+\emph{gray}, or \emph{lightgray}. For more color values, see the
+documentation of the \LaTeXe{} \textsf{color} package.
+
+\item[\cmd{sethmsckeyword}\{\emph{kw}\}] Sets the \HMSC{} keyword to
+\emph{kw}. For this command to be effective, it should be used outside
+the \HMSC{} environment.
+
+\item[\cmd{sethmsckeywordstyle}\{\emph{kwstylemacro}\}] Redefines the
+\verb|\hmsckeywordstyle| macro to the macro \emph{kwstylemacro}. This
+should be a 1-argument macro, like the standard \LaTeX{}
+\cmd{textbf} and \cmd{textit} commands. For this command to be effective, it
+should be used outside the \HMSC{} environment.
+
+\item[\cmd{setmscdockeyword}\{\emph{kw}\}] Sets the \MSCdoc{} keyword to
+\emph{kw}. For this command to be effective, it should be used outside
+the \MSCdoc{} environment.
+
+\item[\cmd{setmscdockeywordstyle}\{\emph{kwstylemacro}\}] Redefines the
+\verb|\mscdockeywordstyle| macro to the macro \emph{kwstylemacro}. This
+should be a 1-argument macro, like the standard \LaTeX{}
+\cmd{textbf} and \cmd{textit} commands. For this command to be effective, it
+should be used outside the \MSCdoc{} environment.
+
+
+\item[\cmd{setmsckeyword}\{\emph{kw}\}] Sets the \MSC{} keyword to
+\emph{kw}. For this command to be effective, it should be used outside
+the \MSC{} environment.
+
+\item[\cmd{setmsckeywordstyle}\{\emph{kwstylemacro}\}] Redefines the
+\verb|\msckeywordstyle| macro to the macro \emph{kwstylemacro}. This
+should be a 1-argument macro, like the standard \LaTeX{}
+\cmd{textbf} and \cmd{textit} commands. For this command to be effective, it
+should be used outside the \MSC{} environment.
+
+\item[\cmd{setmscscale}\{\emph{scalefactor}\}] Sets the scale factor
+of the \MSC{} environment to \emph{scalefactor}. the scale factor is
+supposed to be a real number. Scaling is done when the \MSC{}
+environment ends (\verb|\end{msc}|). The default of \emph{scalefactor}
+is~1.
+
+
+\item[\cmd{setmscvalues}\{\emph{size}\}] Sets the msc-lengths to one
+of the predefined \emph{sizes}. Valid values for \emph{size} are:
+\verb|small|, \verb|normal|, and \verb|large|.
+
+\item[\cmd{setstoptimer}\opt{\emph{pos}}\{\emph{label}\}\{\emph{nm}\}\opt{\emph{offset}}]
+Draws both a \emph{timer} and a \emph{stop timer} symbol on the
+instance \emph{nm}. The parameter \emph{label} defines the name of
+the timer. The optional parameter \emph{pos} defines the position of
+the \emph{timer} relative to the \emph{nm} instance. Valid positions
+are \verb|l| (left) and \verb|r| (right). The default position
+is~\verb|l|. The horizontal distance between the timer symbol and the
+instance axis is defined by \verb+selfmesswidth+.
+
+\item[\cmd{settimeout}\opt{\emph{pos}}\{\emph{label}\}\{\emph{nm}\}\opt{\emph{offset}}]
+Draws a \emph{timer} symbol on the instance \emph{nm} and connects the
+\emph{timer} symbol and the instance with an arrow. The parameter
+\emph{label} defines the name of the \emph{timer}. The optional
+parameter \emph{pos} defines the position of the \emph{timer} relative
+to the \emph{nm} instance. Valid positions are \verb|l| (left) and
+\verb|r| (right). The default position is~\verb|l|. The optional
+parameter \emph{offset} defines the number of levels between the
+\emph{timer} symbol and the point where the arrow meets the \emph{nm}
+instance. The default \emph{offset} is~2. The horizontal distance
+between the timer symbol and the instance axis is defined by
+\verb+selfmesswidth+.
+
+\item[\cmd{settimer}\opt{\emph{pos}}\{\emph{label}\}\{\emph{nm}\}]
+Draws a \emph{timer} symbol on the instance \emph{nm}. The parameter
+\emph{label} defines the name of the timer. The optional parameter
+\emph{pos} defines the position of the \emph{timer} relative to the
+\emph{nm} instance. Valid positions are \verb|l| (left) and \verb|r|
+(right). The default position is~\verb|l|. The horizontal distance
+between the timer symbol and the instance axis is defined by
+\verb+selfmesswidth+.
+
+\item[\cmd{showgrid}] Turns on grid-drawing in \MSC, \MSCdoc, and \HMSC{}
+diagrams. This is useful to determine the values of the user definable
+lengths or if normal \textsf{pstricks} commands should be included in
+the diagram. (Note that the vertical axis of the \MSC{} grid has no positive
+labels.) This command should not be used inside an \MSC,
+\HMSC, or \MSCdoc{} evironment.
+
+\item[\cmd{stop}\{\emph{nm}\}] Stops the instance with nickname
+\emph{nm}. The instance line of \emph{nm} is drawn from its y-position
+to the current y-position of the \MSC{} (\verb|\msc@curentheight|). At
+the current height, a \emph{stop} symbol is drawn.
+
+\item[\cmd{stoptimer}\opt{\emph{pos}}\{\emph{label}\}\{\emph{nm}\}]
+Draws a \emph{stop timer} symbol on the instance \emph{nm}. The
+parameter \emph{label} defines the name of the timer. The optional
+parameter \emph{pos} defines the position of the \emph{timer} relative
+to the \emph{nm} instance. Valid positions are \verb|l| (left) and
+\verb|r| (right). The default position is~\verb|l|. The horizontal
+distance between the timer symbol and the instance axis is defined by
+\verb+selfmesswidth+.
+
+\item[\cmd{timeout}\opt{\emph{pos}}\{\emph{label}\}\{\emph{nm}\}]
+Draws a \emph{timer} symbol on the instance \emph{nm} and connects the
+symbol and the instance with an arrow. The parameter \emph{label}
+defines the name of the timeout. The optional parameter \emph{pos}
+defines the position of the \emph{timer} symbol relative to the
+\emph{nm} instance. Valid positions are \verb|l| (left) and \verb|r|
+(right). The default position is~\verb|l|. The horizontal distance
+between the timer symbol and the instance axis is defined by
+\verb+selfmesswidth+.
+
+\end{defs}
+
+
+\section{User definable lengths}
+
+This section lists the user-definable lengths of the \mscpack. For
+each length, the default values for large, normal, and small diagrams
+are given. The appearance of \MSC, \HMSC, and \MSCdoc{} diagrams can be
+changed by adjusting these lengths. Use the normal \cmd{setlength}
+command to change these lengths.
+
+\begin{defs}
+
+\item[\cmd{actionheight}]
+Height of action symbols.\\
+(\lnsvalue{0.75}{0.6}{0.5} cm.)
+
+\item[\cmd{actionwidth}]
+Width of action symbol.\\
+(\lnsvalue{1.25}{1.25}{1.2} cm.)
+
+\item[\cmd{bottomfootdist}]
+Distance between bottom of foot symbol and frame.\\
+(\lnsvalue{1.0}{0.7}{0.5} cm.)
+
+\item[\cmd{commentdist}]
+Distance between a comment and its instance.\\
+(\lnsvalue{0.5}{0.5}{0.5} cm.)
+
+\item[\cmd{conditionheight}]
+Height of condition symbols.\\
+(\lnsvalue{0.75}{0.6}{0.5} cm.)
+
+\item[\cmd{conditionoverlap}]
+Overlap of condition symbol.\\
+(\lnsvalue{0.6}{0.5}{0.4} cm.)
+
+\item[\cmd{envinstdist}]
+Distance between environments and nearest instance line.\\
+(\lnsvalue{2.5}{2.0}{1.2} cm.)
+
+\item[\cmd{firstlevelheight}] Height of level just below head
+symbols. Should not be changed inside the \MSC{} environment.\\
+(\lnsvalue{0.75}{0.6}{0.4} cm.)
+
+\item[\cmd{hmscconditionheight}]
+Height of \HMSC{} condition symbol.\\
+(\lnsvalue{0.375}{0.3}{0.25} cm.)
+
+\item[\cmd{hmscconditionwidth}]
+Width of \HMSC{} condition symbol.\\
+(\lnsvalue{1.0}{0.8}{0.7} cm.)
+
+\item[\cmd{hmscconnectionradius}]
+Radius of \HMSC{} connection symbol.\\
+(\lnsvalue{0.06}{0.05}{0.04} cm.)
+
+\item[\cmd{hmscreferenceheight}]
+Height of \HMSC{} reference symbol.\\
+(\lnsvalue{0.8}{0.7}{0.6} cm.)
+
+\item[\cmd{hmscreferencewidth}]
+Width of \HMSC{} reference symbol.\\
+(\lnsvalue{1.6}{1.4}{1.2} cm.)
+
+\item[\cmd{hmscstartsymbolwidth}]
+Width of \HMSC{} start symbol.\\
+(\lnsvalue{0.85}{0.7}{0.4} cm.)
+
+\item[\cmd{inlineoverlap}]
+Overlap of inline symbol.\\
+(\lnsvalue{1.5}{1.0}{0.75} cm.)
+
+\item[\cmd{instbarwidth}]
+Default width of vertical instance bars (applies to fat instances only).\\
+(\lnsvalue{0.0}{0.0}{0.0} cm.)
+
+\item[\cmd{instdist}]
+Distance between instance axes.\\
+(\lnsvalue{3.0}{2.2}{1.5} cm.)
+
+\item[\cmd{instfootheight}] Height of foot symbols. Should not be
+changed inside the \MSC{} environment.\\
+(\lnsvalue{0.25}{0.2}{0.15} cm.)
+
+\item[\cmd{instheadheight}] Height of head symbols. Should not be
+changed inside the \MSC{} environment.\\
+(\lnsvalue{0.6}{0.55}{0.5} cm.)
+
+\item[\cmd{instwidth}]
+Width of header and foot symbols.\\
+(\lnsvalue{1.75}{1.6}{1.2} cm.)
+
+\item[\cmd{labeldist}]
+Distance between labels and the symbols to which they belong (for instance, message labels and arrows).\\
+(\lnsvalue{1.0}{1.0}{1.0} ex.)
+
+\item[\cmd{lastlevelheight}] Height of level just above foot
+symbols. Should not be changed inside the \MSC{} environment.\\
+(\lnsvalue{0.5}{0.4}{0.3} cm.)
+
+\item[\cmd{leftnamedist}] Distance between left of the frame and
+(left of) \MSC, \HMSC, or \MSCdoc{} title.\\
+(\lnsvalue{0.3}{0.2}{0.1} cm.)
+
+\item[\cmd{levelheight}]
+Height of a level.\\
+(\lnsvalue{0.75}{0.5}{0.4} cm.)
+
+\item[\cmd{lostsymbolradius}]
+Radius of the lost and found symbols.\\
+(\lnsvalue{0.15}{0.12}{0.08} cm.)
+
+\item[\cmd{markdist}]
+Horizontal distance from a mark to its instance.\\
+(\lnsvalue{1.0}{1.0}{1.0} cm.)
+
+\item[\cmd{measuredist}]
+Horizontal distance from a measure to its (closest) instance.\\
+(\lnsvalue{1.0}{1.0}{1.0} cm.)
+
+\item[\cmd{measuresymbolwidth}]
+Width of a measure symbol.\\
+(\lnsvalue{0.75}{0.6}{0.4} cm.)
+
+\item[\cmd{mscdocreferenceheight}]
+Height of reference symbol in an \MSCdoc.\\
+(\lnsvalue{0.8}{0.7}{0.6} cm.)
+
+\item[\cmd{mscdocreferencewidth}]
+Width of reference symbol in an \MSCdoc.\\
+(\lnsvalue{1.6}{1.4}{1.2} cm.)
+
+\item[\cmd{referenceoverlap}]
+Overlap of reference symbol.\\
+(\lnsvalue{1.5}{1.0}{0.75} cm.)
+
+\item[\cmd{regionbarwidth}]
+Width of region bars.\\
+(\lnsvalue{0.5}{0.4}{0.2} cm.)
+
+\item[\cmd{selfmesswidth}] Length of horizontal arms of self-messages,
+self-orders, lost messages and found messages as well as horizontal
+distance between instance axis and timer symbols.\\
+(\lnsvalue{0.75}{0.6}{0.4} cm.)
+
+\item[\cmd{stopwidth}]
+Width of the stop symbol.\\
+(\lnsvalue{0.6}{0.5}{0.3} cm.)
+
+\item[\cmd{timerwidth}]
+Width of the \emph{timer} symbols.\\
+(\lnsvalue{0.4}{0.3}{0.2} cm.)
+
+\item[\cmd{topheaddist}]
+Distance between top of head symbols and frame.\\
+(\lnsvalue{1.5}{1.3}{1.2} cm.)
+
+\item[\cmd{topnamedist}] Distance between top of the frame and
+(top of) \MSC, \HMSC, or \MSCdoc{} title.\\
+(\lnsvalue{0.3}{0.2}{0.2} cm.)
+
+\end{defs}
+
+
+\section{lnternal lengths}
+
+The \mscpack{} uses some scratch lengths to perform
+calculations. Below, these scratch lengths are listed.
+
+\begin{defs}
+\item[\cmd{msc@commentdist}] Internal length to compute distance
+between comments and instances. (This length should be removed in the
+future.)
+
+\item[\cmd{msc@currentheight}]
+The current height of the current \MSC{} environment.
+
+\item[\cmd{msc@currentwidth}]
+The current width of the current \MSC{} environment.
+
+\item[\cmd{msc@totalheight}]
+The final height of the current \MSC{} environment.
+
+\item[\cmd{msc@totalwidth}]
+The final width of the current \MSC{} environment.
+
+\item[\cmd{tmp@X}]
+Scratch length for intermediate computations.
+
+\item[\cmd{tmp@Xa}]
+Scratch length for intermediate computations.
+
+\item[\cmd{tmp@Xb}]
+Scratch length for intermediate computations.
+
+\item[\cmd{tmp@Xc}]
+Scratch length for intermediate computations.
+
+\item[\cmd{tmp@Xd}]
+Scratch length for intermediate computations.
+
+\item[\cmd{tmp@Y}]
+Scratch length for intermediate computations.
+
+\item[\cmd{tmp@Ya}]
+Scratch length for intermediate computations.
+
+\item[\cmd{tmp@Yb}]
+Scratch length for intermediate computations.
+
+\item[\cmd{tmp@Yc}]
+Scratch length for intermediate computations.
+
+\item[\cmd{tmp@Yd}]
+Scratch length for intermediate computations.
+
+\end{defs}
+
+\section{Internal boxes}
+
+\begin{defs}
+
+\item[\cmd{mscbox}]
+The box that contains the current \MSC{} just before it is put on paper.
+
+\item[\cmd{tmp@box}]
+Scratch box for intermediate computations
+\end{defs}
+
+
+\section{Internal counters}
+
+\begin{defs}
+\item[\cmd{mscinstcnt}] The \MSC{} instance counter. This counter is
+increased each time an instance is created.
+
+\item[\cmd{tmpcnt}] Scratch counter for intermediate computations.
+
+\end{defs}
+
+\section{Limitations}
+
+\begin{enumerate}
+
+\item The frames in an MSC do not automatically scale with the text
+inside the frame. However, the size of the frames can be set manually.
+
+\item Start and end points of messages are computed at the current
+level. This can give ill-looking effects if the width of the bar of an
+instance changes after the message is drawn, e.g., if an activation
+region starts or ends after the message is drawn.
+
+\item Messages that cause the start of a region should be drawn after
+the \verb|\regionstart| command, but in the same level.
+
+\item Messages that denote the end of a region should be
+drawn before the \verb|\regionend| command.
+
+\item Activation regions make crossing messages partly invisible. A
+solution for this problem is to first draw the instance foot symbols
+at the right level (using \verb|\inststop{i}|), then back up the total
+number of levels of the MSC (using \verb|\nextlevel[-n]|), and then
+drawing the messages.
+
+
+\item Documents using the \mscpack{} cannot be compiled with
+\emph{pdflatex}. The reason for this is that \textsf{pstricks} is not
+supported by \emph{pdflatex}.
+
+\item The source code of the \mscpack{} is only marginally
+documented. Therefore, changes/improvements by others are unlikely.
+
+\end{enumerate}
+
+\section{Tricks}
+\label{sec:tricks}
+
+In this section we describe some tricks to use the \mscpack{}
+efficiently.
+
+\paragraph{Multi-line text arguments}
+Many graphical objects in \MSC{} diagrams have text labels. In general,
+the commands to draw these objects put the text arguments on one
+line. If the text should consist of multiple lines, the \LaTeX{}
+\cmd{parbox} command can be used. For instance, to generate a message
+with a two-line label, write:
+
+\verb|\mess{\parbox{1cm}{two\\lines}}{s}{r}|
+
+
+\paragraph{Specifying lengths}
+The \mscpack{} imports the \textsf{calc} package in order to have a
+more natural syntax for arithmetical expressions. Consequently, if a
+command expects a \LaTeX{} length argument, it is possible to use the
+expression syntax offered by \textsf{calc}.
+
+For example, consider the \MSC{} of
+Figure~\ref{fig:specifying:lengths}. To make sure the comment for
+instance~$j$ appears 1ex to the right of the \MSC{} frame, the value
+of the optional \emph{pos} parameter of the \cmd{comment} command
+should be
+\[ \cmd{instdist} + \cmd{envinstdist} + 1\textrm{ex}. \]
+
+To express this in normal \LaTeX, one should write something like
+\begin{verbatim}
+\newlength{\l}
+\setlength{\l}{\instdist}
+\addtolength{\l}{\envinstdist}
+\addtolength{\l}{1ex}
+\msccomment[\l]{Comment for $j$}{j}
+\end{verbatim}
+inside the \MSC{} code. However, using \textsf{calc}'s expression
+syntax, it is also possible to write
+\begin{verbatim}
+
+\msccomment[\instdist + \envinstdist + 1ex]{Comment for $j$}{j}
+\end{verbatim}
+The complete code for the diagram of
+Figure~\ref{fig:specifying:lengths} is given below. Since the
+\textsf{calc} package is included in the standard \LaTeX{}
+distribution, there should be no compatibility problems.
+\begin{figure}[htb]
+\begin{center}
+\begin{msc}{Specifying lengths}
+\declinst{i}{$i$}{}
+\declinst{j}{$j$}{}
+\declinst{k}{$k$}{}
+
+\nextlevel
+\msccomment[\instdist + \envinstdist + 1ex]{Comment for $j$}{j}
+\nextlevel[2]
+\end{msc}
+
+\caption{Specifying lengths}
+\label{fig:specifying:lengths}
+\end{center}
+\end{figure}
+
+{\small
+\begin{verbatim}
+\begin{msc}{Specifying lengths}
+\declinst{i}{$i$}{}
+\declinst{j}{$j$}{}
+\declinst{k}{$k$}{}
+
+\nextlevel
+\msccomment[\instdist + \envinstdist + 1ex]{Comment for $j$}{j}
+\nextlevel[2]
+\end{msc}
+\end{verbatim}
+}
+
+\paragraph{Level backup}
+It is possible to back-up several levels: just use a negative value in
+the \cmd{nextlevel} command. This \emph{feature} can be useful to draw
+messages over regions instead of regions over messages. Compare the
+diagrams of Figure~\ref{fig:level:backup}. The code for these diagrams
+is given below.
+
+\begin{figure}[htb]
+\begin{center}
+\setmscvalues{small}
+\begin{tabular}{cc}
+\begin{msc}{Invisible message label}
+\declinst{i}{$i$}{}
+\declinst{j}{$j$}{}
+\declinst{k}{$k$}{}
+
+\regionstart{activation}{j}
+\nextlevel
+\mess{Message a}{i}[0.25]{k}[2]
+\nextlevel[2]
+\regionend{j}
+\nextlevel
+\end{msc}
+
+&
+
+\begin{msc}{Level backup makes it visible}
+\declinst{i}{$i$}{}
+\declinst{j}{$j$}{}
+\declinst{k}{$k$}{}
+
+\regionstart{activation}{j}
+\nextlevel[3]
+\regionend{j}
+\nextlevel[-2]% backing up
+\mess{Message a}{i}[0.25]{k}[2]
+\nextlevel[2]% fast forward
+\nextlevel
+\end{msc}
+\end{tabular}
+
+\caption{Level back-up}
+\label{fig:level:backup}
+\end{center}
+
+\end{figure}
+
+{\small
+\begin{verbatim}
+\begin{msc}{Invisible message label}
+\declinst{i}{$i$}{}
+\declinst{j}{$j$}{}
+\declinst{k}{$k$}{}
+
+\regionstart{activation}{j}
+\nextlevel
+\mess{Message a}{i}[0.25]{k}[2]
+\nextlevel[2]
+\regionend{j}
+\nextlevel
+\end{msc}
+
+
+\begin{msc}{Level backup makes it visible}
+\declinst{i}{$i$}{}
+\declinst{j}{$j$}{}
+\declinst{k}{$k$}{}
+
+\regionstart{activation}{j}
+\nextlevel[3]
+\regionend{j}
+\nextlevel[-2]% backing up
+\mess{Message a}{i}[0.25]{k}[2]
+\nextlevel[2]% fast forward
+\nextlevel
+\end{msc}
+\end{verbatim}
+}
+
+
+\paragraph{Automatic resizing of actions}
+
+Consider the \MSC{} of Figure~\ref{fig:small:action}. The source code
+for this diagram is:
+{
+\small
+\begin{verbatim}
+\begin{msc}{small action}
+\declinst{i}{$i$}{}
+\declinst{j}{$j$}{}
+\action{\parbox{1cm}{\centering Do it now}}{i}
+\nextlevel[2]
+\end{msc}
+\end{verbatim}
+}
+
+\begin{figure}[htb]
+\begin{center}
+\begin{msc}{small action}
+\declinst{i}{$i$}{}
+\declinst{j}{$j$}{}
+\action{\parbox{1cm}{\centering Do it now}}{i}
+\nextlevel[2]
+\end{msc}
+\end{center}
+
+\caption{Small action symbol}
+\label{fig:small:action}
+\end{figure}
+
+It is clear that the action symbol is too small for the action
+label. The normal solution to this problem would be to change the
+values of \cmd{actionwidth} and \cmd{actionheight} such that the
+\cmd{parbox} containing the action label fits in the frame of the
+action symbol.
+
+Instead of computing these lengths and adding the necessary
+\cmd{setlength} commands manually, it would be nice to have a macro
+that computes and adjusts the lengths as required. The \cmd{Action} macro
+defined below does just that.
+{
+\small
+\begin{verbatim}
+\newsavebox{\labelbox}
+\newlength{\oldwd}
+\newlength{\oldht}
+\newcommand{\Action}[2]{%
+ \setlength{\oldwd}{\actionwidth}%
+ \setlength{\oldht}{\actionheight}%
+ \savebox{\labelbox}{#1}%
+ \setlength{\actionwidth}{\wd\labelbox + 2\labeldist}%
+ \setlength{\actionheight}{\ht\labelbox + \dp\labelbox + 2\labeldist}%
+ \action{\usebox{\labelbox}}{#2}%
+ \setlength{\actionwidth}{\oldwd}%
+ \setlength{\actionheight}{\oldht}%
+}
+\end{verbatim}
+} Note that we define a box (\cmd{labelbox}) and two lengths
+(\cmd{oldwd} and \cmd{oldht}) as scratch variables. Furthermore,
+before changing the width and height of action symbols, the old values
+are saved in \cmd{oldwd} and \cmd{oldht}, respectively. The new width
+and height of action symbols accomodate for white space around the
+action label by using the \mscpack{} length \cmd{labeldist}. After
+changing the lengths, the action is drawn using the normal
+\cmd{action} command. Finally, the old values of \cmd{actionwidth} and
+\cmd{actionheight} are restored.
+
+
+\newsavebox{\labelbox}
+\newlength{\oldwd}
+\newlength{\oldht}
+\newcommand{\Action}[2]{%
+ \setlength{\oldwd}{\actionwidth}%
+ \setlength{\oldht}{\actionheight}%
+ \savebox{\labelbox}{#1}%
+ \setlength{\actionwidth}{\wd\labelbox + 2\labeldist}%
+ \setlength{\actionheight}{\ht\labelbox + \dp\labelbox + 2\labeldist}%
+ \action{\usebox{\labelbox}}{#2}%
+ \setlength{\actionwidth}{\oldwd}%
+ \setlength{\actionheight}{\oldht}%
+}
+
+Figure~\ref{fig:resizing:action} shows the effect of automatic
+resizing action symbols. Instance~$i$ has automically resizing
+action. The actions of instance~$j$ are normal actions that show the
+new \cmd{Action} command changes the size of one action symbol
+only. The source of this diagram is given below.
+
+\begin{figure}[htb]
+\begin{center}
+\begin{msc}{small action}
+\declinst{i}{$i$}{}
+\declinst{j}{$j$}{}
+\action{A}{j}
+\Action{\parbox{1cm}{\centering Do it now}}{i}
+\nextlevel[2]
+\action{B}{j}
+\nextlevel[2]
+\end{msc}
+\end{center}
+
+\caption{Automatic resizing action symbol}
+\label{fig:resizing:action}
+\end{figure}
+
+
+{
+\small
+\begin{verbatim}
+\begin{msc}{small action}
+\declinst{i}{$i$}{}
+\declinst{j}{$j$}{}
+\action{A}{j}
+\Action{\parbox{1cm}{\centering Do it now}}{i}
+\nextlevel[2]
+\action{B}{j}
+\nextlevel[2]
+\end{msc}
+\end{verbatim}
+}
+
+
+\bibliographystyle{plain}
+\bibliography{biblio}
+
+\end{document}
+