% file msc.sty
% LaTeX macros to draw message sequence charts
%
% RCS version: $Id: msc.sty,v 1.1 2000/06/19 10:07:22 lamarre Exp $
%
% Copyright S. Mauw and V. Bos
% Eindhoven University of Technology
% P.O. Box 513
% 5600 MB Eindhoven
% The Netherlands
% Email: sjouke@win.tue.nl, vbos@win.tue.nl
% Updates via: http://www.win.tue.nl/cs/fm/sjouke/mscpackage.html
%
\def\mscdate{1999/07/19}% update this whenever this file changes
\def\mscversion{1.47}%   update this whenever a new version is ready
\NeedsTeXFormat{LaTeX2e}% 
\ProvidesPackage{msc}[\mscdate, v\mscversion]
\typeout{msc version \mscversion. (\mscdate)}
\RequirePackage{pstricks,calc,ifthen}
%
% msc lengths
% First the customizable lengths:
\newlength{\topheaddist}% distance between top of head symbols and frame
\newlength{\instheadheight}% height of head symbols
\newlength{\firstlevelheight}% height of level just below head symbols
\newlength{\levelheight}% height of a level
\newlength{\lastlevelheight}% height of level just above foot symbols
\newlength{\instfootheight}% height of foot symbols
\newlength{\bottomfootdist}% distance between bottom of foot symbol and frame
\newlength{\instwidth}%  width of header and foot symbols
\newlength{\instdist}% distance between (vertical) instance lines
\newlength{\envinstdist}% distance between environments and nearest instance line
\newlength{\topmscnamedist}% distance between top of frame and (top of) msc title 
\newlength{\selfmesswidth}% length of horizontal arms of self messages
\newlength{\labeldist}% distance between labels and message lines or head symbol boxes 
\newlength{\coregionbarwidth}% width of coregion bars, preferably less than \instwidth 
\newlength{\lostsymbolradius}% radius of the lost and found symbols
\newlength{\timerwidth}% width of the timer symbols
\newlength{\stopwidth}% width of the stop symbol
\newlength{\actionheight}% height of action symbols
\newlength{\actionwidth}% width of action symbol
\newlength{\conditionheight}% height of condition symbols
\newlength{\conditionoverlap}% overlap of condition symbol
\newlength{\referenceoverlap}% overlap of reference symbol
\newlength{\inlineoverlap}% overlap of inline symbol
%
% Now the internal lengths
\newlength{\tmp@X}
\newlength{\tmp@Y}
\newlength{\tmp@Xa}
\newlength{\tmp@Ya}
\newlength{\tmp@Xb}
\newlength{\tmp@Yb}
\newlength{\msc@currentheight}
\newlength{\msc@currentwidth}
\newlength{\msc@totalwidth}
\newlength{\msc@totalheight}
%
% some internal offsets
\def\msc@headoffset{\topheaddist+\instheadheight+\firstlevelheight}
\def\msc@leveloffset{0}% 
\def\mscscalefactor{1}%
\newcommand{\setmscscale}[1]{\def\mscscalefactor{#1}}%
%
% Command to change the footer color (legal values are black, gray,
% lightgray, and white)
\def\setfootcolor#1{\def\msc@footcolor{#1}}
%
% And some internal counters
\newcounter{mscinstcnt}
\newcounter{tmpcnt}
%
% \selfmesslabelpos defines the position of message labels of
% self messages. The default value is "l" (left) other value(s) are "r" (right)
\def\selfmesslabelpos{l}
%
% \msc@selfmesslabelpos is the internal variant of \selfmesslabelpos
% This internal variant is used by the actual  drawing commands for self messages
\def\msc@selfmesslabelpos{l}
%
% \msc@setselfmesslabelpos sets the internal \mes@selfmesslabelpos
\def\msc@setselfmesslabelpos#1{
  \ifthenelse{\not\(\equal{#1}{l} \or \equal{#1}{r}\)}{%
    \msc@unknownselfmesslabelposerr{#1}}{% else
    \def\msc@selfmesslabelpos{#1}%
  }%
}
%
% \dummyinst declares a dummy msc-instance and does not draws its head symbol
% nor its instance axis until an instance create is encountered.
% #1: nickname that can be used in \mess
% 
% Some commands are defined as well (INSTNR is the arabic
% representation of the instance number):
%   \instnicknameINSTNR: returns the nickname of instance INSTNR
%   \instxposINSTNR: returns the x-position of instance with nickname #1
%   \instyposINSTNR: returns the last y-position of instance with nickname #1
%   \instlinestyle#1: the line style (dashed or solid) of instance with nickname #1
\def\dummyinst#1{% user command to declare instances
  \@ifundefined{mscinst#1}{%
    \ifthenelse{\value{mscinstcnt}=2}{% Aha: this is the first msc instance, so, add the
      \addtolength{\msc@currentwidth}{\envinstdist}% left \envinstdist to \currentwidth
    }{\relax}% non-first inst, just relax
    % make an instance with empty inside name and empty above name:
    \msc@declinst{#1}{\relax}{\relax}%
    \setlength{\tmp@X}{\msc@instxpos{#1}}%
    % update the x position of the right environment:
    \setlength{\tmp@X}{\msc@currentwidth+\envinstdist}%
    \msc@setinstxpos{envright}{\the\tmp@X}
    % update the current width of the msc:
    \addtolength{\msc@currentwidth}{\instdist}%
    % make y-pos undefined, to make sure that no instance line will be drawn
    \msc@setinstypos{#1}{undefined}% --added sm
  }{% else: nickname #1 already defined!
    \msc@nicknamedefinederr{#1}%
  }
}
%
% \declinst declares a new msc-instance and draws its head symbol
% #1: nickname that can be used in \mess
% #2: name of the instance (above instance head symbol)
% #3: name of the instance (inside instance head symbol)
% 
% Some commands are defined as well (INSTNR is the arabic
% representation of the instance number):
%   \instabname#1: `above name' of instance with nickname #1 
%   \instinname#1: `inside name' of instance with nickname #1 
%   \instnicknameINSTNR: returns the nickname of instance INSTNR
%   \instxposINSTNR: returns the x-position of instance with nickname #1
%   \instyposINSTNR: returns the last y-position of instance with nickname #1
%   \instlinestyle#1: the line style (dashed or solid) of instance with nickname #1
\def\declinst#1#2#3{% user command to declare instances
  \@ifundefined{mscinst#1}{%
    \ifthenelse{\value{mscinstcnt}=2}{% Aha: this is the first msc instance, so, add the
      \addtolength{\msc@currentwidth}{\envinstdist}% left \envinstdist to \currentwidth
    }{\relax}% non-first inst, just relax
    \msc@declinst{#1}{#2}{#3}%
    \msc@drawinstancehead{#1}{#2}{#3}%
    \setlength{\tmp@X}{\msc@instxpos{#1}}%
    % update the x position of the right environment:
    \setlength{\tmp@X}{\msc@currentwidth+\envinstdist}%
    \msc@setinstxpos{envright}{\the\tmp@X}
    % update the current width of the msc:
    \addtolength{\msc@currentwidth}{\instdist}%
  }{% else: nickname #1 already defined!
    \msc@nicknamedefinederr{#1}%
  }
}
%
%
\def\msc@declinst#1#2#3{% internal command to declare instances
  \@ifundefined{mscinst#1}{%
    \@namedef{mscinst#1}{\relax}%  
    \expandafter\def\csname instabname#1\endcsname{#2}% `above name'
    \expandafter\def\csname instinname#1\endcsname{#3}% `inside name'
    \expandafter\def\csname instnickname\arabic{mscinstcnt}\endcsname{#1}%
    % the x position of an instance, \instxpos#1, is stored as a string, not as
    % a TeX-length, since that would use up too much of TeX limited number of
    % length-registers.
    % However, this means we first have to calculate the x-pos, and then
    % assign the string representation of the result to \instxpos#1:
    \setlength{\tmp@X}{\msc@currentwidth}%
    \expandafter\edef\csname instxpos#1\endcsname{\the\tmp@X}%
    \setlength{\tmp@Y}{\topheaddist+\instheadheight}%
    \expandafter\edef\csname instypos#1\endcsname{\the\tmp@Y}%
    \expandafter\def\csname instlinestyle#1\endcsname{solid}%
    \stepcounter{mscinstcnt}%
  }{% else, #1 already defined
    \msc@nicknamedefinederr{#1}%
  }
}
%
% \msc@instnickname gets the nickname of msc instance with number #1
% (This macro is used in \msc@drawinstancelevels)
\def\msc@instnickname#1{%
  \csname instnickname\arabic{#1}\endcsname%
}
%
% \msc@instxpos gets the x position (i.e., horizontal position) of the
% msc instance with nickname #1. 
\def\msc@instxpos#1{%
  \expandafter\@ifundefined{mscinst#1}{%
    \msc@instundefinederr{#1}}{% else, #1 is defined
%    \def\msc@tmpexp{instxpos#1}%
    \expandafter\csname instxpos#1\endcsname}%
}
%
% \msc@setinstxpos sets the x position of instance with nickname #1 to
% the string  #2
\def\msc@setinstxpos#1#2{%
  \expandafter\@ifundefined{mscinst#1}{%
    \msc@instundefinederr{#1}}{% else, #1 is defined
    \expandafter\edef\csname instxpos#1\endcsname{#2}%
  }%
}
%
% \msc@instypos gets the last y position (i.e., vertical position) of the
% msc instance with nickname #1. 
\def\msc@instypos#1{%
  \expandafter\@ifundefined{mscinst#1}{%
    \msc@instundefinederr{#1}}{% else, #1 is defined
    \csname instypos#1\endcsname}%
}
%
% \msc@setinstypos sets the last y position of instance with nickname #1 to
% the string #2
\def\msc@setinstypos#1#2{%
  \expandafter\@ifundefined{mscinst#1}{%
    \msc@instundefinederr{#1}}{% else, #1 is defined
    \expandafter\edef\csname instypos#1\endcsname{#2}%
  }%
}
%
% Change \instlinestyle command of msc instance with ninkname #1 into #2
% #2 should be one of: solid, dashed, or dotted
\def\msc@setinstlinestyle#1#2{%
  \expandafter\@ifundefined{mscinst#1}{%
    \msc@instundefinederr{#1}}{% else, #1 is defined
    \ifthenelse{\not\(\equal{#2}{solid} \or
                      \equal{#2}{dashed} \or
                      \equal{#2}{dotted}\)}{% unknown linestyle
      \msc@unknownlinestyleerr{#2}}{%
      \expandafter\def\csname instlinestyle#1\endcsname{#2}%
    }%
  }%
}
%
% \msc@instlinestyle returns the linestyle of instance with nickname #1
\def\msc@instlinestyle#1{%
  \expandafter\@ifundefined{mscinst#1}{%
    \msc@instundefinederr{#1}}{% else, #1 is defined
    \csname instlinestyle#1\endcsname}%
}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%5
%
% CREATE
%
% \create creates a new msc-instance and draws its head symbol
% #1: text above creation message
% #2: nickname of creating instance
% #3: nickname of created instance
% #4: name of the instance (above instance head symbol)
% #5: name of the instance (inside instance head symbol)
% 
% Some commands are defined as well (INSTNR is the arabic
% representation of the instance number):
%   \instabname#3: `above name' of instance with nickname #3 
%   \instinname#3: `inside name' of instance with nickname #3 
%   \instlinestyle#3: the line style (dashed or solid) of instance with nickname #3
\def\create#1#2#3#4#5{%
  \expandafter\@ifundefined{mscinst#2}{%
    \msc@instundefinederr{#2}}{% else, #2 is defined
  \expandafter\@ifundefined{mscinst#3}{%
    \msc@instundefinederr{#3}}{% else, #3 is defined
    \expandafter\def\csname instabname#3\endcsname{#4}% `above name'
    \expandafter\def\csname instinname#3\endcsname{#5}% `inside name'
    % draw the instance header symbol
    \setlength{\tmp@X}{\msc@instxpos{#3}}% x-center head box
    \setlength{\tmp@Y}{\msc@currentheight+\msc@headoffset}% y-center head box
    \setlength{\tmp@Xa}{-0.5\instwidth+\tmp@X}% x-upperleft head box
    \setlength{\tmp@Ya}{\msc@currentheight+\msc@headoffset-0.5\instheadheight}%
    \setlength{\tmp@Xb}{\tmp@Xa+\instwidth}% x-lowerright head box
    \setlength{\tmp@Yb}{\tmp@Ya+\instheadheight}% y-lowerright head box
    \psframe(\tmp@Xa,-\tmp@Ya)(\tmp@Xb,-\tmp@Yb)%
    \rput[B](\tmp@X,-\tmp@Ya){\raisebox{\labeldist}{\makebox[0pt][c]{#4}}}%
    \rput[B](\tmp@X,-\tmp@Y){\raisebox{-.5ex}{\makebox[0pt][c]{#5}}}%
    % redefine the instance's y position
    \setlength{\tmp@Y}{\msc@currentheight+0.5\instheadheight+\msc@headoffset}%
    \msc@setinstypos{#3}{\the\tmp@Y}%
    % draw creation arrow
    \setlength{\tmp@Xa}{\msc@instxpos{#2}}%
    \setlength{\tmp@Ya}{\msc@currentheight+\msc@headoffset}%
    \setlength{\tmp@Yb}{\msc@currentheight+\msc@headoffset}%
    \setlength{\tmp@Xb}{\msc@instxpos{#3}}%
    \ifthenelse{\lengthtest{\tmp@Xa < \tmp@Xb}}{% arrow comes from the left
      \setlength{\tmp@Xb}{\tmp@Xb-0.5\instwidth}%
    }{% else arrow comes from the right
      \setlength{\tmp@Xb}{\tmp@Xb+0.5\instwidth}%
    }%
     \msc@drawmessage{\tmp@Xa}{\tmp@Ya}{\tmp@Xb}{\tmp@Yb}{#1}{dashed}%
  }%
  }%
}
%
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% INLINE EXPRESSIONS (inlines)
%
%
% \inlineestart creates an inline expression at the current level
% [#1]: overlap
% #2: nickname of the inline
% #3: text of the inline
% #4: first instance of the inline
% #5: final instance of the inline
\newcommand{\inlinestart}[5][\inlineoverlap]{\msc@declinline{#1}{#2}{#3}{#4}{#5}}%
%
% \inlineend draws and ends the inline expression with nickname #1
% 
\newcommand{\inlineend}{%
  \@ifstar{\msc@inlineends}{\msc@inlineend}}
%
% \inlineseparator draws a ``separator'' (horizontal dashed line) through 
% inline expression with nickname #1
\newcommand{\inlineseparator}[1]{%
  \expandafter\@ifundefined{mscinl#1}{%
    \msc@inlundefinederr{#1}}{% else, #1 is defined
    \setlength{\tmp@Y}{\msc@currentheight+\msc@headoffset}%
    \psline[linestyle=dashed](\msc@inlulx{#1},-\tmp@Y)(\msc@inllrx{#1},-\tmp@Y)%
  }%
}
%
% internal commands to implement the inline expressions:
%
\def\msc@declinline#1#2#3#4#5{%
  \@ifundefined{mscinl#2}{%
    \@ifundefined{mscinst#4}{% #4 is not an instance nickname
      \msc@instundefinederr{#4}}{%
      \@ifundefined{mscinst#5}{% #5 is not an instance nickname
        \msc@instundefinederr{#5}}{%
        \ifthenelse{\lengthtest{\msc@instxpos{#4}>\msc@instxpos{#5}}}{%
          \msc@inlfirstlasterror{#2}{#4}{#5}}{%
          \@namedef{mscinl#2}{\relax}%
          \expandafter\def\csname inltext#2\endcsname{#3}%
          \setlength{\tmp@X}{\msc@instxpos{#4}-#1}%
          \expandafter\edef\csname inlulx#2\endcsname{\the\tmp@X}%
          \expandafter\edef\csname inluly#2\endcsname{\the\msc@currentheight}%
          \setlength{\tmp@X}{\msc@instxpos{#5}+#1}%
          \expandafter\edef\csname inllrx#2\endcsname{\the\tmp@X}%
          \expandafter\edef\csname inllry#2\endcsname{undefined}%
          % two additional instances are defined
          \msc@declinst{#2left}{\relax}{\relax}% left of inline
          \msc@setinstxpos{#2left}{\msc@inlulx{#2}}%
          \msc@setinstypos{#2left}{undefined}% no instance line drawing
          \msc@declinst{#2right}{\relax}{\relax}% left of inline
          \msc@setinstxpos{#2right}{\msc@inllrx{#2}}%
          \msc@setinstypos{#2right}{undefined}% no instance line drawing
        }%
      }%
    }%
  }{% nickname #2 already defined
    \msc@nicknamedefinederr{#2}%
  }%
}
%
% \msc@inlulx gets the upper-left x-position of inline with nickname #1.
\def\msc@inlulx#1{%
  \expandafter\@ifundefined{mscinl#1}{%
    \msc@inlundefinederr{#1}}{% else, #1 is defined
    \csname inlulx#1\endcsname%
  }%
}
%
% \msc@inluly gets the upper-left y-position of inline with nickname #1.
\def\msc@inluly#1{%
  \expandafter\@ifundefined{mscinl#1}{%
    \msc@inlundefinederr{#1}}{% else, #1 is defined
    \csname inluly#1\endcsname%
  }%
}
%
% \msc@inllrx gets the lower-right x-position of inline with nickname #1.
\def\msc@inllrx#1{%
  \expandafter\@ifundefined{mscinl#1}{%
    \msc@inlundefinederr{#1}}{% else, #1 is defined
    \csname inllrx#1\endcsname%
  }%
}
%
% \msc@inllry gets the lower-right y-position of inline with nickname #1.
\def\msc@inllry#1{%
  \expandafter\@ifundefined{mscinl#1}{%
    \msc@inlundefinederr{#1}}{% else, #1 is defined
    \csname inllry#1\endcsname%
  }%
}
%
% \msc@inltext gets the text of inline with nickname #1
\def\msc@inltext#1{%
  \expandafter\@ifundefined{mscinl#1}{%
    \msc@inlundefinederr{#1}}{% else, #1 is defined
    \csname inltext#1\endcsname%
  }%
}
%
% \msc@inlineend completes the inline with nickname #1
% (the bottom line is solid)
\def\msc@inlineend#1{%
  \expandafter\@ifundefined{mscinl#1}{%
    \msc@inlundefinederr{#1}}{% else, #1 is defined
    \expandafter\edef\csname inllry#1\endcsname{\the\msc@currentheight}%
    \setlength{\tmp@Xa}{\msc@inlulx{#1}}%
    \setlength{\tmp@Ya}{\msc@inluly{#1}+\msc@headoffset}%
    \setlength{\tmp@Xb}{\msc@inllrx{#1}}%
    \setlength{\tmp@Yb}{\msc@inllry{#1}+\msc@headoffset}%
%% Debug info:
%    \typeout{(\tmp@Xa,-\tmp@Ya)(\tmp@Xb,-\tmp@Yb)}%
    \psframe(\tmp@Xa,-\tmp@Ya)(\tmp@Xb,-\tmp@Yb)%
    \settowidth{\tmp@X}{\msc@inltext{#1}}%
    \setlength{\tmp@X}{1.1\tmp@X+\labeldist}%
    \settoheight{\tmp@Y}{\msc@inltext{#1}}%
    \setlength{\tmp@Y}{1.1\tmp@Y+\labeldist}%
    \setlength{\tmp@Xb}{\tmp@X+\labeldist}%
    \setlength{\tmp@Yb}{\tmp@Y+\labeldist}%
    \rput(\tmp@Xa,-\tmp@Ya){%
      \rput[tl](\labeldist,-\labeldist){\msc@inltext{#1}}%
      \psline(0,-\tmp@Yb)(\tmp@X,-\tmp@Yb)(\tmp@Xb,-\tmp@Y)(\tmp@Xb,0)%
    }%
  }%
}
%
% \msc@inlineends completes the inline with nickname #1
% (the bottom line is dashed)
\def\msc@inlineends#1{%
  \expandafter\@ifundefined{mscinl#1}{%
    \msc@inlundefinederr{#1}}{% else, #1 is defined
    \expandafter\edef\csname inllry#1\endcsname{\the\msc@currentheight}%
    \setlength{\tmp@Xa}{\msc@inlulx{#1}}%
    \setlength{\tmp@Ya}{\msc@inluly{#1}+\msc@headoffset}%
    \setlength{\tmp@Xb}{\msc@inllrx{#1}}%
    \setlength{\tmp@Yb}{\msc@inllry{#1}+\msc@headoffset}%
%% Debug info:
%    \typeout{(\tmp@Xa,-\tmp@Ya)(\tmp@Xb,-\tmp@Yb)}%
    % first the solid part of the inline expression:
    \psline(\tmp@Xa,-\tmp@Yb)(\tmp@Xa,-\tmp@Ya)(\tmp@Xb,-\tmp@Ya)(\tmp@Xb,-\tmp@Yb)%
    % then the dashed bottom line:
    \psline[linestyle=dashed](\tmp@Xa,-\tmp@Yb)(\tmp@Xb,-\tmp@Yb)
    \settowidth{\tmp@X}{\msc@inltext{#1}}%
    \setlength{\tmp@X}{1.1\tmp@X+\labeldist}%
    \settoheight{\tmp@Y}{\msc@inltext{#1}}%
    \setlength{\tmp@Y}{1.1\tmp@Y+\labeldist}%
    \setlength{\tmp@Xb}{\tmp@X+\labeldist}%
    \setlength{\tmp@Yb}{\tmp@Y+\labeldist}%
    \rput(\tmp@Xa,-\tmp@Ya){%
      \rput[tl](\labeldist,-\labeldist){\msc@inltext{#1}}%
      \psline(0,-\tmp@Yb)(\tmp@X,-\tmp@Yb)(\tmp@Xb,-\tmp@Y)(\tmp@Xb,0)%
    }%
  }%
}
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% REFERENCES
%
%
% \referencestart creates an msc reference at the current level
% [#1] : overlap
% #2: nickname of the reference
% #3: text of the reference
% #4: first instance of the reference
% #5: final instance of the reference
\newcommand{\referencestart}[5][\referenceoverlap]{%
  \msc@declreference{#1}{#2}{#3}{#4}{#5}%
  \setcounter{tmpcnt}{0}%
  \msc@reffindfirst{#2}{\msc@drawtorefaux}%
}
%
% \referenceend draws and ends the reference with nickname #1 
\newcommand{\referenceend}[1]{%
  \msc@drawreference{#1}%
  \setcounter{tmpcnt}{0}%
  \setlength{\tmp@Y}{\msc@currentheight+\msc@headoffset}%
  \msc@reffindfirst{#1}{\msc@refresetypos{\the\tmp@Y}}%
}
%
% internal commands to implement references:
%
\def\msc@declreference#1#2#3#4#5{%
  \@ifundefined{mscref#2}{%
    \@ifundefined{mscinst#4}{% #4 is not an instance nickname
      \msc@instundefinederr{#4}}{%
      \@ifundefined{mscinst#5}{% #5 is not an instance nickname
        \msc@instundefinederr{#5}}{%
        \ifthenelse{\lengthtest{\msc@instxpos{#4}>\msc@instxpos{#4}}}{%
          \msc@reffirstlasterror{#2}{#4}{#5}}{%
          \@namedef{mscref#2}{\relax}%
          \expandafter\def\csname reftext#2\endcsname{#3}%
          \setlength{\tmp@X}{\msc@instxpos{#4}-#1}%
          \expandafter\edef\csname refulx#2\endcsname{\the\tmp@X}%
          \expandafter\edef\csname refuly#2\endcsname{\the\msc@currentheight}%
          \setlength{\tmp@X}{\msc@instxpos{#5}+#1}%
          \expandafter\edef\csname reflrx#2\endcsname{\the\tmp@X}%
          \expandafter\edef\csname reflry#2\endcsname{undefined}%
          \expandafter\def\csname reffirst#2\endcsname{#4}%
          \expandafter\def\csname reffinal#2\endcsname{#5}%
          % two additional instances are defined
          \msc@declinst{#2left}{\relax}{\relax}% left of reference
          \msc@setinstxpos{#2left}{\msc@refulx{#2}}%
          \msc@setinstypos{#2left}{undefined}% no instance line drawing
          \msc@declinst{#2right}{\relax}{\relax}% left of reference
          \msc@setinstxpos{#2right}{\msc@reflrx{#2}}%
          \msc@setinstypos{#2right}{undefined}% no instance line drawing
        }%
      }%
    }%
  }{% nickname #1 already defined
    \msc@nicknamedefinederr{#2}%
  }%
}
%
% \msc@refulx gets the upper-left x-position of reference with nickname #1.
\def\msc@refulx#1{%
  \expandafter\@ifundefined{mscref#1}{%
    \msc@refundefinederr{#1}}{% else, #1 is defined
    \csname refulx#1\endcsname%
  }%
}
%
% \msc@refuly gets the upper-left y-position of reference with nickname #1.
\def\msc@refuly#1{%
  \expandafter\@ifundefined{mscref#1}{%
    \msc@refundefinederr{#1}}{% else, #1 is defined
    \csname refuly#1\endcsname%
  }%
}
%
% \msc@reflrx gets the lower-right x-position of reference with nickname #1.
\def\msc@reflrx#1{%
  \expandafter\@ifundefined{mscref#1}{%
    \msc@refundefinederr{#1}}{% else, #1 is defined
    \csname reflrx#1\endcsname%
  }%
}
%
% \msc@reflry gets the lower-right y-position of reference with nickname #1.
\def\msc@reflry#1{%
  \expandafter\@ifundefined{mscref#1}{%
    \msc@refundefinederr{#1}}{% else, #1 is defined
    \csname reflry#1\endcsname%
  }%
}
%
% \msc@reftext gets the text of reference with nickname #1
\def\msc@reftext#1{%
  \expandafter\@ifundefined{mscref#1}{%
    \msc@refundefinederr{#1}}{% else, #1 is defined
    \csname reftext#1\endcsname%
  }%
}
%
% \msc@reftext gets the nickname of the first instance of the reference with nickname #1
\def\msc@reffirst#1{%
  \expandafter\@ifundefined{mscref#1}{%
    \msc@refundefinederr{#1}}{% else, #1 is defined
    \csname reffirst#1\endcsname%
  }%
}
%
% \msc@reftext gets the nickname of the final instance of the reference with nickname #1
\def\msc@reffinal#1{%
  \expandafter\@ifundefined{mscref#1}{%
    \msc@refundefinederr{#1}}{% else, #1 is defined
    \csname reffinal#1\endcsname%
  }%
}
%
% \msc@drawreference completes the reference with nickname #1
\def\msc@drawreference#1{%
  \expandafter\@ifundefined{mscref#1}{%
    \msc@refundefinederr{#1}}{% else, #1 is defined
    \expandafter\edef\csname reflry#1\endcsname{\the\msc@currentheight}%
    \setlength{\tmp@Xa}{\msc@refulx{#1}}%
    \setlength{\tmp@Ya}{\msc@refuly{#1}+\msc@headoffset}%
    \setlength{\tmp@Xb}{\msc@reflrx{#1}}%
    \setlength{\tmp@Yb}{\msc@reflry{#1}+\msc@headoffset}%
%% Debug info:
%    \typeout{(\tmp@Xa,-\tmp@Ya)(\tmp@Xb,-\tmp@Yb)}%
    \psframe[framearc=0.25](\tmp@Xa,-\tmp@Ya)(\tmp@Xb,-\tmp@Yb)% note: rounded corners
    \setlength{\tmp@X}{\tmp@Xb-\tmp@Xa}%
    \setlength{\tmp@Y}{\tmp@Yb-\tmp@Ya}%
    \rput(\tmp@Xa,-\tmp@Ya){%
      \rput[B](.5\tmp@X,-.5\tmp@Y){\raisebox{-.5ex}{\makebox[0pt][c]{\msc@reftext{#1}}}}%
    }%
  }%
}
%
\def\msc@reffindfirst#1#2{%
  \ifthenelse{\value{tmpcnt} < \value{mscinstcnt}}{%
% Debug info:
%    \typeout{(drawtoref) checking \msc@instnickname{tmpcnt}}%
    \ifthenelse{\equal{\msc@instnickname{tmpcnt}}{\msc@reffirst{#1}}}{% first instance found
% Debug info:
%      \typeout{first found: \msc@instnickname{tmpcnt}}%
      #2{#1}}{% else, keep on looking
      \stepcounter{tmpcnt}%
      \msc@reffindfirst{#1}{#2}}}{% done ! all instances checked
  }%
}
%
\def\msc@drawtorefaux#1{%
  \ifthenelse{\value{tmpcnt} < \value{mscinstcnt}}{%
% Debug info:
%    \typeout{(drawtorefaux) checking \msc@instnickname{tmpcnt}}%
   \msc@drawinstanceline{\msc@instnickname{tmpcnt}}%
   \msc@setinstypos{\msc@instnickname{tmpcnt}}{undefined}%
   \ifthenelse{\equal{\msc@instnickname{tmpcnt}}{\msc@reffinal{#1}}}{% final instance found
% Debug info:
%      \typeout{final found: \msc@instnickname{tmpcnt}}%
     }{% else, non-final
      \stepcounter{tmpcnt}%
      \msc@drawtorefaux{#1}}%
  }{% done ! all instances checked
  }%
}
%
\def\msc@refresetypos#1#2{%
  \ifthenelse{\value{tmpcnt} < \value{mscinstcnt}}{%
% Debug info:
%    \typeout{(drawtorefaux) checking \msc@instnickname{tmpcnt}}
   \msc@setinstypos{\msc@instnickname{tmpcnt}}{#1}%
   \ifthenelse{\equal{\msc@instnickname{tmpcnt}}{\msc@reffinal{#2}}}{% final instance found
% Debug info:
%      \typeout{final found: \msc@instnickname{tmpcnt}}%
     }{% else, non-final
      \stepcounter{tmpcnt}%
      \msc@refresetypos{#1}{#2}}%
  }{% done ! all instances checked
  }%
}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  CO-REGIONS
%
% \coregionstart starts a coregion on instance #1 (nickname) in the current level.
\def\coregionstart#1{\msc@coregionstartend{#1}{dashed}}%
% \coregionend ends a coregion on instance #1 (nickname) in the current level.
\def\coregionend#1{\msc@coregionstartend{#1}{solid}}%
%
% internal commands to implement co-regions:
%
\def\msc@coregionstartend#1#2{%
  \expandafter\@ifundefined{mscinst#1}{%
    \msc@instundefinederr{#1}}{% else, #1 is defined
    \msc@drawinstanceline{#1}%
    \msc@drawcoregionbar{#1}%
    \setlength{\tmp@Y}{\msc@currentheight+\msc@headoffset}%
    \msc@setinstypos{#1}{\the\tmp@Y}%
    \msc@setinstlinestyle{#1}{#2}%
  }%
}
%
\def\msc@drawcoregionbar#1{%
  \expandafter\@ifundefined{mscinst#1}{%
    \msc@instundefinederr{#1}}{% else, #1 is defined
    \setlength{\tmp@Xa}{-.5\coregionbarwidth+\msc@instxpos{#1}}%
    \setlength{\tmp@Xb}{.5\coregionbarwidth+\msc@instxpos{#1}}%
    \setlength{\tmp@Ya}{\msc@currentheight+\msc@headoffset}
    \psline(\tmp@Xa,-\tmp@Ya)(\tmp@Xb,-\tmp@Ya)%
  }%
}
%
% \messarrowscale sets the arrow scale
\def\messarrowscale#1{\psset{arrowscale=#1}}
%
% \msc@setleveloffset sets the internal level offset
\def\msc@setleveloffset#1{%
  \def\msc@leveloffset{#1}%
}
%
% \mess has one optional argument to define the position of
% the label of a self message.
\newcommand{\mess}[1][\selfmesslabelpos]{%
  \msc@setselfmesslabelpos{#1}%
  \@messdispatcher{mess}%
}
%
% \order has one optional argument to define the position of
% the label of a self order.
\newcommand{\order}[1][\selfmesslabelpos]{%
  \msc@setselfmesslabelpos{#1}%
  \@messdispatcher{order}{0}%
}
%
% \@messdispatcher, \@oargmessdispatcher, and \@nooargmessdispatcher
% together handle the different forms of the user comands \order and \mess.
%
% \@messdispatcher checks for an optional argument defining the level
% offset. If the optional argument is present, \@oargmessdispatcher is
% called, otherwise \@nooargmessdispatcher is called.
% Both \@oargmessdispatcher and \@nooargmessdispatcher are dispatchers for
% the  macros:
%   \msc@selfmess
%   \msc@mess
\def\@messdispatcher#1#2#3#4{%
  \@ifnextchar[{\@oargmessdispatcher{#1}{#2}{#3}{#4}}{\@nooargmessdispatcher{#1}{#2}{#3}{#4}}}
%
\def\@oargmessdispatcher#1#2#3#4[#5]{%
  \def\msc@a{#3}%
  \def\msc@b{#4}%
  \ifx\msc@a\msc@b%
    \msc@setleveloffset{#5}%
    \msc@selfmess{#1}{#2}{#3}%
  \else%
    \msc@setleveloffset{#5}%
    \msc@mess{#1}{#2}{#3}{#4}%
  \fi%
}
%
% \@nooargmessdispatcher does not expect the optional level-offset argument,
% but uses the default offset values to set \msc@leveloffset.  
\def\@nooargmessdispatcher#1#2#3#4{%
  \def\msc@a{#3}%
  \def\msc@b{#4}%
  \ifx\msc@a\msc@b%
    \msc@setleveloffset{1}% default level-offset value for self messages 
    \msc@selfmess{#1}{#2}{#3}%
  \else%
    \msc@setleveloffset{0}% default level-offset value for non-self messages
    \msc@mess{#1}{#2}{#3}{#4}%
  \fi%
}
%
% \@mess draws a message from `from-instance' to `to-instance'
% #1: type of the message
% #2: name of the message
% #3: nickname from-instance
% #4: nickname to-instance
\def\msc@mess#1#2#3#4{%
  \expandafter\@ifundefined{mscinst#3}{%
    \msc@instundefinederr{#3}}{% else, #3 is defined
    \expandafter\@ifundefined{mscinst#4}{%
      \msc@instundefinederr{#4}}{% else, #4 is defined
      \setlength{\tmp@Xa}{\msc@instxpos{#3}}%
      \setlength{\tmp@Ya}{\msc@currentheight+\msc@headoffset}%
      \setlength{\tmp@Xb}{\msc@instxpos{#4}}%
      \setlength{\tmp@Yb}{\msc@currentheight+\msc@headoffset+\levelheight*\msc@leveloffset}%
      \msc@messtypeselection{#1}{\tmp@Xa}{\tmp@Ya}{\tmp@Xb}{\tmp@Yb}{#2}%
    }%
  }%
}
%
% \msc@selfmess draws a self-message or a self-orderline on an instance.
% #1: flag indicating if this is a message (mess) or an orderline (order)
% #2: name of the message
% #3: nickname of the instance
\def\msc@selfmess#1#2#3{%
  \expandafter\@ifundefined{mscinst#3}{%
    \msc@instundefinederr{#3}}{% else, #3 is defined
    \setlength{\tmp@Xa}{\msc@instxpos{#3}}%
    \setlength{\tmp@Ya}{\msc@currentheight+\msc@headoffset}%
    \setlength{\tmp@Yb}{\tmp@Ya+\levelheight*\msc@leveloffset}%
    \setlength{\tmp@Y}{\tmp@Ya+0.5\tmp@Yb-0.5\tmp@Ya}%
    \ifthenelse{\equal{\msc@selfmesslabelpos}{l}}{% then left of instance
      \setlength{\tmp@Xb}{\tmp@Xa-\selfmesswidth}%
      \setlength{\tmp@X}{\tmp@Xb-\labeldist}%
      \def\msc@justification{r}%
    }{% else right of instance
      \setlength{\tmp@Xb}{\tmp@Xa+\selfmesswidth}%
      \setlength{\tmp@X}{\tmp@Xb+\labeldist}%
      \def\msc@justification{l}
    }%
    \ifthenelse{\equal{#1}{mess}}{% draw a self message
      \psline{->}(\tmp@Xa,-\tmp@Ya)(\tmp@Xb,-\tmp@Ya)(\tmp@Xb,-\tmp@Yb)(\tmp@Xa,-\tmp@Yb)%
      \rput(\tmp@X,-\tmp@Y){\makebox[0pt][\msc@justification]{#2}}%
    }{% else, draw a self orderline
      \psline[linestyle=dotted]{->}(\tmp@Xa,-\tmp@Ya)(\tmp@Xb,-\tmp@Ya)(\tmp@Xb,-\tmp@Y)%
      \psline[linestyle=dotted](\tmp@Xb,-\tmp@Y)(\tmp@Xb,-\tmp@Yb)(\tmp@Xa,-\tmp@Yb)%
    }%
  }%
}
%
% \msc@messtypeselection selects on base of first argument if an
% orderline or a message should be drawn
\def\msc@messtypeselection#1#2#3#4#5#6{%
   \ifthenelse{\equal{#1}{mess}}{%
     \msc@drawmessage{#2}{#3}{#4}{#5}{#6}{normal}}{% else orderline
     \msc@draworder{#2}{#3}{#4}{#5}
   }%
}
%
% \msc@draworder draws an orderline from (#1,#2) to (#3,#4)
\def\msc@draworder#1#2#3#4{%
   \setlength{\tmp@Xa}{#1}%
   \setlength{\tmp@Ya}{#2}%
   \setlength{\tmp@Xb}{#3}%
   \setlength{\tmp@Yb}{#4}%
   \setlength{\tmp@X}{0.4\tmp@Xa+0.6\tmp@Xb}%
   \setlength{\tmp@Y}{0.4\tmp@Ya+0.6\tmp@Yb}%
   \psline[linestyle=dotted]{->}(\tmp@Xa,-\tmp@Ya)(\tmp@X,-\tmp@Y)%
   \psline[linestyle=dotted](\tmp@X,-\tmp@Y)(\tmp@Xb,-\tmp@Yb)%
}
%
% \msc@drawmessage draws a message from (#1,#2) to (#3,#4) and puts
% the label #5 near the message
% #6 is either "dashed" or "normal" and determines drawing mode
\def\msc@drawmessage#1#2#3#4#5#6{%
   \setlength{\tmp@Xa}{#1}%
   \setlength{\tmp@Ya}{#2}%
   \setlength{\tmp@Xb}{#3}%
   \setlength{\tmp@Yb}{#4}%
   \setlength{\tmp@X}{\tmp@Xb-\tmp@Xa}%
   \setlength{\tmp@Y}{\tmp@Yb-\tmp@Ya}%
   \ifthenelse{\lengthtest{\tmp@Y=0pt}}{%
     \def\msc@justification{c}%
   }{% else
     \ifthenelse{\(\lengthtest{\tmp@X<0pt} \and \lengthtest{\tmp@Y>0pt}\)%
                 \or%
                 \(\lengthtest{\tmp@X>0pt} \and \lengthtest{\tmp@Y<0pt}\)}{%
       \def\msc@justification{r}%
     }{% else
       \def\msc@justification{l}%
     }%
   }%
   \ifthenelse{\lengthtest{\tmp@Xa<\tmp@Xb}}{%
     \setlength{\tmp@X}{\tmp@Xa+0.5\tmp@Xb-0.5\tmp@Xa}}{%
     \setlength{\tmp@X}{\tmp@Xb+0.5\tmp@Xa-0.5\tmp@Xb}}%
   \ifthenelse{\lengthtest{\tmp@Ya<\tmp@Yb}}{%
     \setlength{\tmp@Y}{\tmp@Ya+0.5\tmp@Yb-0.5\tmp@Ya}}{%
     \setlength{\tmp@Y}{\tmp@Yb+0.5\tmp@Ya-0.5\tmp@Yb}}%
   \ifthenelse{\equal{#6}{normal}}{% draw normal line
     \psline{->}(\tmp@Xa,-\tmp@Ya)(\tmp@Xb,-\tmp@Yb)%
   }{ %else draw dashed line
     \psline[linestyle=dashed]{->}(\tmp@Xa,-\tmp@Ya)(\tmp@Xb,-\tmp@Yb)%
   }%
   \rput[B](\tmp@X,-\tmp@Y){\raisebox{\labeldist}{\makebox[0pt][\msc@justification]{#5}}}%
% debugging info:
%   \message{(msg: #5, justification: \msc@justification)}%
}
%
% \lost has one optional argument to define the position of
% the label of a self message.
\newcommand{\lost}[1][\selfmesslabelpos]{%
  \msc@setselfmesslabelpos{#1}%
  \def\msc@arrowdirection{->}%
  \def\msc@circlefillstyle{black}%
  \@lostfound{lost}%
}
%
% \found has one optional argument to define the position of
% the label of a self message.
\newcommand{\found}[1][\selfmesslabelpos]{%
  \msc@setselfmesslabelpos{#1}%
  \def\msc@arrowdirection{<-}%
  \def\msc@circlefillstyle{white}%
  \@lostfound{found}%
}
%
% \@lostfound draws lost and found messages
% #1: type  of the message (lost/found)
% #2: name of the message
% #3: name of the gate
% #4: nickname of the instance
\def\@lostfound#1#2#3#4{%
  \expandafter\@ifundefined{mscinst#4}{%
    \msc@instundefinederr{#4}}{% else, #4 is defined
    \setlength{\tmp@Xa}{\msc@instxpos{#4}}%
    \setlength{\tmp@Ya}{\msc@currentheight+\msc@headoffset}%
    \ifthenelse{\equal{\msc@selfmesslabelpos}{l}}{% then put label left
      \setlength{\tmp@Xb}{\tmp@Xa-\selfmesswidth}%
      \psline{\msc@arrowdirection}(\tmp@Xa,-\tmp@Ya)(\tmp@Xb,-\tmp@Ya)%
      \setlength{\tmp@X}{0.6\tmp@Xa+0.4\tmp@Xb}%
      \setlength{\tmp@Y}{\tmp@Ya-\lostsymbolradius-\labeldist}%
      \rput[B](\tmp@X,-\tmp@Y){\makebox[0pt][r]{#2}}%
      \setlength{\tmp@Xb}{\tmp@Xb-\lostsymbolradius}%
      \pscircle[fillstyle=solid,fillcolor=\msc@circlefillstyle]%
           (\tmp@Xb,-\tmp@Ya){\lostsymbolradius}
      \setlength{\tmp@X}{\tmp@Xb-\lostsymbolradius-\labeldist}%
      \setlength{\tmp@Y}{\tmp@Ya+0.5ex}%
      \rput[B](\tmp@X,-\tmp@Y){\makebox[0pt][r]{#3}}%
    }{% else, put label right
      \setlength{\tmp@Xb}{\tmp@Xa+\selfmesswidth}%
      \psline{\msc@arrowdirection}(\tmp@Xa,-\tmp@Ya)(\tmp@Xb,-\tmp@Ya)%
      \setlength{\tmp@X}{0.6\tmp@Xa+0.4\tmp@Xb}%
      \setlength{\tmp@Y}{\tmp@Ya-\lostsymbolradius-\labeldist}%
      \rput[B](\tmp@X,-\tmp@Y){\makebox[0pt][l]{#2}}%
      \setlength{\tmp@Xb}{\tmp@Xb+\lostsymbolradius}%
      \pscircle[fillstyle=solid,fillcolor=\msc@circlefillstyle]%
           (\tmp@Xb,-\tmp@Ya){\lostsymbolradius}
      \setlength{\tmp@X}{\tmp@Xb+\lostsymbolradius+\labeldist}%
      \setlength{\tmp@Y}{\tmp@Ya+0.5ex}%
      \rput[B](\tmp@X,-\tmp@Y){\makebox[0pt][l]{#3}}%
    }%
  }%
}
%
%
% \settimer has one optional argument to define the position of
% the label of a self message.
\newcommand{\settimer}[1][\selfmesslabelpos]{%
  \msc@setselfmesslabelpos{#1}%
  \@timer{set}%
}
%
%
% \timeout has one optional argument to define the position of
% the label of a self message.
\newcommand{\timeout}[1][\selfmesslabelpos]{%
  \msc@setselfmesslabelpos{#1}%
  \@timer{timeout}%
}
%
%
% \stoptimer has one optional argument to define the position of
% the label of a self message.
\newcommand{\stoptimer}[1][\selfmesslabelpos]{%
  \msc@setselfmesslabelpos{#1}%
  \@timer{stop}%
}
%
%
% \settimeout has one optional argument to define the position of
% the label of a self message.
\newcommand{\settimeout}[1][\selfmesslabelpos]{%
  \msc@setselfmesslabelpos{#1}%
  \@timerdispatcher{settimeout}%
}
%
%
% \setstoptimer has one optional argument to define the position of
% the label of a self message.
\newcommand{\setstoptimer}[1][\selfmesslabelpos]{%
  \msc@setselfmesslabelpos{#1}%
  \@timerdispatcher{setstoptimer}%
}
\def\@timerdispatcher#1#2#3{%
  \@ifnextchar[{\@oargtimerdispatcher{#1}{#2}{#3}}{\@nooargtimerdispatcher{#1}{#2}{#3}}}
%
\def\@oargtimerdispatcher#1#2#3[#4]{%
  \msc@setleveloffset{#4}%
  \@timer{#1}{#2}{#3}%
}
%
\def\@nooargtimerdispatcher#1#2#3{%
  \msc@setleveloffset{2}% default level-offset value for combined timers
  \@timer{#1}{#2}{#3}%
}
%
%
% \@timer draws timers
% #1: type  of the timer (set/timeout/stop)
% #2: label
% #3: nickname of the instance
\def\@timer#1#2#3{%
  \expandafter\@ifundefined{mscinst#3}{%
    \msc@instundefinederr{#3}}{% else, #3 is defined
    \setlength{\tmp@Xa}{\msc@instxpos{#3}}%
    \setlength{\tmp@Ya}{\msc@currentheight+\msc@headoffset}%
    \ifthenelse{\equal{\msc@selfmesslabelpos}{l}}{% point left of axis
      \setlength{\tmp@Xb}{\tmp@Xa-\selfmesswidth}%
    }{ % else point right of axis
      \setlength{\tmp@Xb}{\tmp@Xa+\selfmesswidth}%
    }%
    \ifthenelse{\equal{#1}{timeout}}{% draw an arrow
      \psline{<-}(\tmp@Xa,-\tmp@Ya)(\tmp@Xb,-\tmp@Ya)%
    }{ % else draw a line without arrow head
      \psline(\tmp@Xa,-\tmp@Ya)(\tmp@Xb,-\tmp@Ya)%
    }%
    \setlength{\tmp@X}{\tmp@Xb}% This looks clumsy - sm
    \setlength{\tmp@Y}{\tmp@Ya}%
    \msc@drawtimer{#1}{\tmp@X}{\tmp@Y}{\msc@selfmesslabelpos}{#2}%
    \ifthenelse{\equal{#1}{settimeout}}{% draw second part of settimeout
      \setlength{\tmp@Ya}{\tmp@Y+\levelheight*\msc@leveloffset}%
      \setlength{\tmp@Y}{\tmp@Y+0.75\timerwidth}%
      \psline{->}(\tmp@X,-\tmp@Y)(\tmp@X,-\tmp@Ya)(\msc@instxpos{#3},-\tmp@Ya)%
    }{ % else not settimeout
      \ifthenelse{\equal{#1}{setstoptimer}}{% draw second part of setstoptimer
        \setlength{\tmp@Ya}{\tmp@Y+\levelheight*\msc@leveloffset}%
        \setlength{\tmp@Y}{\tmp@Y+0.75\timerwidth}%
        \psline(\tmp@X,-\tmp@Y)(\tmp@X,-\tmp@Ya)(\msc@instxpos{#3},-\tmp@Ya)%
        \setlength{\tmp@Y}{\tmp@Ya}%
        \msc@drawtimer{stop}{\tmp@X}{\tmp@Y}{\msc@selfmesslabelpos}{}%
      }{ % else no second part needed
      }%
    }%
  }%
}
%
% \msc@drawtimer draws the timer symbols
% #1: type  of the timer (set/timeout/stop)
% #2: x-coordinate of center of timer
% #3: y-coordinate of center of timer
% #4: place text left (l) or right (r)
% #5: text added to the timer
\def\msc@drawtimer#1#2#3#4#5{%
  \setlength{\tmp@Xa}{#2-0.5\timerwidth}%
  \setlength{\tmp@Xb}{#2+0.5\timerwidth}%
  \ifthenelse{\equal{#1}{stop}}{% draw reset symbol
    \setlength{\tmp@Ya}{-#3+0.5\timerwidth}%
    \setlength{\tmp@Yb}{-#3-0.5\timerwidth}%
    \psline(\tmp@Xa,\tmp@Ya)(\tmp@Xb,\tmp@Yb)%
    \psline(\tmp@Xb,\tmp@Ya)(\tmp@Xa,\tmp@Yb)%
  }{% else draw set/timeout symbol
    \setlength{\tmp@Ya}{-#3+0.75\timerwidth}%
    \setlength{\tmp@Yb}{-#3-0.75\timerwidth}%
    \psline(\tmp@Xa,\tmp@Ya)(\tmp@Xb,\tmp@Yb)%
           (\tmp@Xa,\tmp@Yb)(\tmp@Xb,\tmp@Ya)(\tmp@Xa,\tmp@Ya)%
  }%
  \ifthenelse{\equal{#4}{l}}{% place label left
    \setlength{\tmp@Xa}{#2-\labeldist-0.3ex}%
    \setlength{\tmp@Ya}{-#3-0.5ex}%
    \rput[B](\tmp@Xa,\tmp@Ya){\makebox[0pt][r]{#5}}
  }{% else place label right
    \setlength{\tmp@Xa}{#2+\labeldist+0.3ex}%
    \setlength{\tmp@Ya}{-#3-0.5ex}%
    \rput[B](\tmp@Xa,\tmp@Ya){\makebox[0pt][l]{#5}}%
  }%
}
%
%
% \msc@drawinstancehead draws the head of the instance
% #1: nickname of the instance
% #2: text to put above the instance head symbol
% #3: text to put inside the instance head symbol
\def\msc@drawinstancehead#1#2#3{%
  \setlength{\tmp@X}{\msc@instxpos{#1}}% x-center head box
  \setlength{\tmp@Y}{\topheaddist+0.5\instheadheight}% y-center head box
  \setlength{\tmp@Xa}{-0.5\instwidth+\tmp@X}% x-upperleft head box
  \setlength{\tmp@Ya}{\topheaddist}% y-upperleft head box
  \setlength{\tmp@Xb}{\tmp@Xa+\instwidth}% x-lowerright head box
  \setlength{\tmp@Yb}{\topheaddist+\instheadheight}% y-lowerright head box
  \ifthenelse{\equal{\msc@insthead}{yes}}{%
    \psframe(\tmp@Xa,-\tmp@Ya)(\tmp@Xb,-\tmp@Yb)%
  }{% else, no head symbol drawing%
  }
  \rput[B](\tmp@X,-\tmp@Ya){\raisebox{\labeldist}{\makebox[0pt][c]{#2}}}%
  \rput[B](\tmp@X,-\tmp@Y){\raisebox{-.5ex}{\makebox[0pt][c]{#3}}}%
}
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\def\msc@drawinstanceline#1{%
  \expandafter\@ifundefined{mscinst#1}{%
    \msc@instundefinederr{#1}}{% else, #1 is defined
      \ifthenelse{\equal{\msc@instypos{#1}}{undefined}}{% y-pos undefined: no line needed
      }{% else
        \setlength{\tmp@X}{\msc@instxpos{#1}}%
        \setlength{\tmp@Ya}{\msc@instypos{#1}}%
        \setlength{\tmp@Yb}{\msc@currentheight+\msc@headoffset}%
        \psline[linestyle=\msc@instlinestyle{#1}](\tmp@X,-\tmp@Ya)(\tmp@X,-\tmp@Yb)%
     }%
  }%
}
%
% \msc@drawinstancefoot draws the last level and foot of the instance
% #1: nickname of the instance
\def\msc@drawinstancefoot#1{%
  \setlength{\tmp@Xa}{-0.5\instwidth+\msc@instxpos{#1}}%
  \setlength{\tmp@Ya}{\msc@currentheight+\msc@headoffset}%
  \setlength{\tmp@Xb}{\tmp@Xa+\instwidth}%
  \setlength{\tmp@Yb}{\msc@currentheight+\msc@headoffset+\instfootheight}%
  \ifthenelse{\equal{\msc@instfoot}{yes}}{
    \psframe[fillstyle=solid,fillcolor=\msc@footcolor](\tmp@Xa,-\tmp@Ya)(\tmp@Xb,-\tmp@Yb)%
  }{% else, no foot symbol drawing%
  }
}
%
% \nextlevel increases \msc@currentheight by #1 * \levelheight
% (optional) #1: an integer number (defaults to 1) 
\newcommand{\nextlevel}[1][1]{%
  \addtolength{\msc@currentheight}{#1\levelheight}%
}
%
\def\msc@drawinstancefooters{%
  \ifthenelse{\value{tmpcnt} < \value{mscinstcnt}}{%
     % Only draw the instancefoot if the instypos is defined (not ``undefined'')
     % This signals a previous instance stop.
     \ifthenelse{\equal{\msc@instypos{\msc@instnickname{tmpcnt}}}{undefined}}{\relax}{%
      \msc@drawinstanceline{\msc@instnickname{tmpcnt}}%
      \msc@drawinstancefoot{\msc@instnickname{tmpcnt}}%
    }%
    \stepcounter{tmpcnt}%
    \msc@drawinstancefooters}{% else nothing
  }}%
%
% \action puts an action symbol on the instance with nickname #2.
% The action symbol will be placed on the current level and the text #1
% is centered inside the action symbol.
\def\action#1#2{%
  \expandafter\@ifundefined{mscinst#2}{%
    \msc@instundefinederr{#2}}{% else, #2 is defined
    % first, draw the instance line as far as possible
    \msc@drawinstanceline{#2}%
    % then, draw the action symbol
    \setlength{\tmp@Xa}{\msc@instxpos{#2}-0.5\actionwidth}%
    \setlength{\tmp@Xb}{\tmp@Xa+\actionwidth}%
    \setlength{\tmp@Ya}{\msc@currentheight+\msc@headoffset}%
    \setlength{\tmp@Yb}{\tmp@Ya+\actionheight}%
    \psframe(\tmp@Xa,-\tmp@Ya)(\tmp@Xb,-\tmp@Yb)%
    \setlength{\tmp@X}{\msc@instxpos{#2}}%
    \setlength{\tmp@Y}{\tmp@Ya+0.5\actionheight}%
    \rput[B](\tmp@X,-\tmp@Y){\raisebox{-.5ex}{\makebox[0pt][c]{#1}}}%
    % redefine the instance's y position
    \setlength{\tmp@Y}{\msc@currentheight+\actionheight+\msc@headoffset}%
    \msc@setinstypos{#2}{\the\tmp@Y}%
  }%
}
%
% \stop ends the instance with nickname #1.
\def\stop#1{%
  \expandafter\@ifundefined{mscinst#1}{%
    \msc@instundefinederr{#1}}{% else, #1 is defined
    % first, draw the instance line as far as possible
    \msc@drawinstanceline{#1}%
    % then, draw the stop symbol
    \setlength{\tmp@X}{\msc@instxpos{#1}}%
    \setlength{\tmp@Ya}{\msc@instypos{#1}}%
    \setlength{\tmp@Yb}{\msc@currentheight+\msc@headoffset}%
    \setlength{\tmp@Xa}{\tmp@X-0.5\stopwidth}%
    \setlength{\tmp@Xb}{\tmp@X+0.5\stopwidth}%
    \setlength{\tmp@Ya}{\tmp@Yb+0.5\stopwidth}%
    \setlength{\tmp@Yb}{\tmp@Yb-0.5\stopwidth}%
    \psline(\tmp@Xa,-\tmp@Ya)(\tmp@Xb,-\tmp@Yb)%
    \psline(\tmp@Xb,-\tmp@Ya)(\tmp@Xa,-\tmp@Yb)%
    % redefine the instance's y position
    % ``undefined'' means that the instance axis will not be drawn any further
    \msc@setinstypos{#1}{undefined}%
  }%
}
%
%
% \condition puts a condition symbol over the given instances
% #1: name to be put inside the condition symbol
% #2: comma-separated list of instance nicknames, such that:
%     - The first instance nickname is supposed to be the leftmost 
%       instance of the condition
%     - The last instance nickname is supposed to be the rightmost
%       instance of the condition
\def\condition#1#2{%
  \def\msc@conditiontext{#1}%
  \def\msc@firstconditioninst{undefined}%
  \def\msc@lastconditioninst{undefined}%
  \msc@condition{#2}%
% debugging info:
%  \message{(msc: condition: \msc@firstconditioninst...\msc@lastconditioninst)}%
  \setlength{\tmp@Xa}{\msc@instxpos{\msc@firstconditioninst}-\conditionoverlap}%
  \setlength{\tmp@Ya}{\msc@currentheight+\msc@headoffset}%
  \setlength{\tmp@Xb}{\msc@instxpos{\msc@lastconditioninst}+\conditionoverlap}%
  \setlength{\tmp@Yb}{\tmp@Ya+\conditionheight}%
  \msc@drawcondition{#1}{\tmp@Xa}{\tmp@Ya}{\tmp@Xb}{\tmp@Yb}%
}
%
\def\msc@condition#1{%
  \@for\msccondition@rg:=#1\do{%
    \expandafter\@ifundefined{mscinst\msccondition@rg}{%
      \msc@instundefinederr{\msccondition@rg}}{% else, \msccondition@rg is defined
% debugging info:
%     \message{(msc: condition instance "\msccondition@rg")}%
      \ifthenelse{\equal{\msc@firstconditioninst}{undefined}}{%
        \edef\msc@firstconditioninst{\msccondition@rg}%
      }{\ifthenelse{\lengthtest{\msc@instxpos{\msc@firstconditioninst} > \msc@instxpos{\msccondition@rg}}}{%
          \edef\msc@firstconditioninst{\msccondition@rg}}{}%
      }%
      \ifthenelse{\equal{\msc@lastconditioninst}{undefined}}{%
        \edef\msc@lastconditioninst{\msccondition@rg}%
      }{\ifthenelse{\lengthtest{\msc@instxpos{\msc@lastconditioninst} < \msc@instxpos{\msccondition@rg}}}{%
          \edef\msc@lastconditioninst{\msccondition@rg}}{}%
      }
      % now, draw the instance line as far as possible
      \setlength{\tmp@X}{\msc@instxpos{\msccondition@rg}}%
      \setlength{\tmp@Ya}{\msc@instypos{\msccondition@rg}}%
      \setlength{\tmp@Yb}{\msc@currentheight+\msc@headoffset}%
      \psline[linestyle=\msc@instlinestyle{\msccondition@rg}](\tmp@X,-\tmp@Ya)(\tmp@X,-\tmp@Yb)%
      % and redefine the instance's y position
      \setlength{\tmp@Y}{\msc@currentheight+\conditionheight+\msc@headoffset}%
      \msc@setinstypos{\msccondition@rg}{\the\tmp@Y}% 
    }%
  }%
}
%
% \msc@drawcondition draw the condition symbol
% #1: condition-text
\newlength{\tmp@tx}%
\newlength{\tmp@ty}%
\def\msc@drawcondition#1#2#3#4#5{%
  \setlength{\tmp@tx}{#4+ .6#5 - .6#3}%
  \setlength{\tmp@ty}{.5#3 + .5#5}%
  \psline(#2,-#3)(#4,-#3)(\tmp@tx,-\tmp@ty)(#4,-#5)%
  \setlength{\tmp@tx}{#2- .6#5 + .6#3}%
  \psline(#4,-#5)(#2,-#5)(\tmp@tx,-\tmp@ty)(#2,-#3)%
  \setlength{\tmp@tx}{.5#2 + .5#4}%
  \setlength{\tmp@ty}{.5#3 + .5#5}%
  \rput[B](\tmp@tx,-\tmp@ty){\raisebox{-.5ex}{\makebox[0pt][c]{#1}}}%
}
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%   GATES  (Bill ?)
% \gate[hpos][vpos]{text}{nickname}
% \gate*[hpos][vpos]{text}{nickname} 
%   (starred version puts a dot at the position of the gate on the instance line)
%
% hpos: optional horizontal position argument l(eft) or r(ight). default: l
% vpos: optional vertical position argument t(op), c(enter) or b(ottom). default: t
% text: text to be placed at the gate
% nickname:  nickname of the instance to which the gate belongs
%
\def\gate{\@ifstar{\def\msc@gatestar{defined}\msc@gateh}{\def\msc@gatestar{undefined}\msc@gateh}}
\newcommand{\msc@gateh}[1][l]{%
  \def\msc@gatehpos{#1}%
  \msc@gatev%
}
%
\newcommand{\msc@gatev}[3][t]{%
  \expandafter\@ifundefined{mscinst#3}{%
    \msc@instundefinederr{#3}}{% else, #3 is defined
    \ifthenelse{\equal{\msc@gatestar}{defined}}{%
      \setlength{\tmp@X}{\msc@instxpos{#3}}%
      \setlength{\tmp@Y}{\msc@currentheight + \msc@headoffset}%
      \pscircle[fillstyle=solid,fillcolor=black](\tmp@X,-\tmp@Y){.5mm}}{}%
    \ifthenelse{\equal{t}{#1}}{
      \setlength{\tmp@Y}{\msc@currentheight + \msc@headoffset - \labeldist}%
      \def\msc@gatetext{{#2}}%
    }{%
    \ifthenelse{\equal{c}{#1}}{%
      \setlength{\tmp@Y}{\msc@currentheight + \msc@headoffset}%
      \def\msc@gatetext{\raisebox{-.5\totalheight}{#2}}%
    }{%
      \setlength{\tmp@Y}{\msc@currentheight + \msc@headoffset + \labeldist}%
      \def\msc@gatetext{\raisebox{-\totalheight}{#2}}%
    }}%
    \ifthenelse{\equal{l}{\msc@gatehpos}}{%
      \setlength{\tmp@X}{\msc@instxpos{#3} - \labeldist}%
      \rput[B](\tmp@X,-\tmp@Y){\makebox[0pt][r]{\msc@gatetext}}}{%
      \setlength{\tmp@X}{\msc@instxpos{#3} + \labeldist}%
      \rput[B](\tmp@X,-\tmp@Y){\makebox[0pt][l]{\msc@gatetext}}}%
  }
}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% \drawmscframe draws a frame of the right size around the msc
% This command also set the value of \msc@totalsizebox
\def\msc@drawframe{%
  \global\msc@totalwidth =\msc@currentwidth%
  \setlength{\tmp@Y}{\msc@currentheight+\msc@headoffset+\instfootheight+\bottomfootdist}%
  \global\msc@totalheight =\tmp@Y%
  \ifthenelse{\equal{\msc@frame}{yes}}{%
    \psframe(0,0)(\msc@totalwidth,-\msc@totalheight)%
  }{% no frame drawing
  }%
}
%
% \msckeyword is the keyword representation of msc
\def\msckeyword{msc}
\def\msckeywordstyle#1{\textbf{#1}}
%
% This keyword can be changed by the \setmckeyword command (or by \renewcommand{\msckeyword}{...}):
\newcommand{\setmsckeyword}[1]{\def\msckeyword{#1}}
\newcommand{\setmsckeywordstyle}[1]{\def\msckeywordstyle{#1}}%
%
% Commands to switch internal options that control the drawing of header and footer symbols
\newcommand{\drawinsthead}[1]{\def\msc@insthead{#1}}% 
\drawinsthead{yes}%
\newcommand{\drawinstfoot}[1]{\def\msc@instfoot{#1}}% 
\drawinstfoot{yes}%
% A similar command to control drawing of the msc-frame
\newcommand{\drawframe}[1]{\def\msc@frame{#1}}% 
\drawframe{yes}%
%
% \msc@settitle places #1 (the title) in the upperleft
% corner of the msc frame
\def\msc@settitle{%
  \rput[tl](0,-\topmscnamedist){%
    \makebox[\msc@totalwidth][\msc@titlejustification]{\hspace*{4pt}\msckeywordstyle{\msckeyword}{} \msc@title\hspace*{4pt}}%
  }%
}
%
% \msc@title stores the title given in \begin{msc}{title}
\def\msc@title{}%
%
% \msc@titlejustification says how the title should be justified
% Justification is relative to the total width of the msc 
% l: left (default)
% c: centered
% r: right
\def\msc@titlejustification{l}
%
\newsavebox{\mscbox}%
%
% the msc-environment
\newenvironment{msc}[2][l]{%
 \message{( \msckeyword: "#2"}%
 \def\msc@titlejustification{#1}%
 \def\msc@title{#2}%
 \setcounter{mscinstcnt}{0}%
 \setlength{\msc@currentheight}{0pt}%
 \setlength{\msc@currentwidth}{0pt}%
 % define the artificial left and right environment instances
 \msc@declinst{envleft}{}{}%
 \msc@setinstxpos{envleft}{0pt}%
 \msc@declinst{envright}{}{}%
 \setlength{\tmp@X}{2\envinstdist}%
 \msc@setinstxpos{envright}{\the\tmp@X}%
 \begin{lrbox}{\mscbox}
 \begin{pspicture}(0,0)% we draw the msc in a picture of size 0x0
   \psset{dash=4pt 4pt}% sets the hashed linestyle style
 }{%
 \addtolength{\msc@currentheight}{\lastlevelheight}%
 \setcounter{tmpcnt}{2}%
 \msc@drawinstancefooters%
 % If there is at least one instance, the current width is 
 % set to the xpos of the NEXT msc instance. There is at least one instance,
 % if mscinstcnt >= 3. So, in that case, we have to 
 % substract one \instdist from the current width.
 \ifthenelse{\value{mscinstcnt}<3}{% no user defined instances, so, add the 
   \addtolength{\msc@currentwidth}{\envinstdist}% left (postponed) envinstdist to currentwidth
 }{% mscinstcnt >= 3
   \addtolength{\msc@currentwidth}{-\instdist}%
 }%
 % Now we compute the final current width: one extra \envinstdist:
 \addtolength{\msc@currentwidth}{\envinstdist}
 \msc@drawframe%
 \msc@settitle%
 \end{pspicture}% 
% Debug info:
%\typeout{msc size: \the\msc@totalwidth x\the\msc@totalheight}%
 \end{lrbox}%
 % the \mscbox now contains a box of 0x0, however the actual width and
 % height are stored in \msc@total{width,height}. We use these lengths
 % to adjust the width and height of the \mscbox
 \wd\mscbox=\msc@totalwidth%
 \ht\mscbox=\msc@totalheight%
 % Now the \mscbox can be scaled (by \mscscalefactor) and `printed':
 \scalebox{\mscscalefactor}{\raisebox{\msc@totalheight}[\msc@totalheight][0pt]{\usebox{\mscbox}}}%
 \message{)}%
}
%
\def\mscunit{cm}%
\def\setmscunit#1{\gdef\mscunit{#1}}
%
% \set@mscvalueslarge 
\def\set@mscvalueslarge{%
  \psset{linewidth=0.8pt}
  % the lengths
  \setlength{\topheaddist}{1.5\mscunit}
  \setlength{\bottomfootdist}{1\mscunit}
  \setlength{\instheadheight}{.6\mscunit} 
  \setlength{\instfootheight}{0.25\mscunit} 
  \setlength{\levelheight}{.75\mscunit} 
  \setlength{\firstlevelheight}{0.75\mscunit} 
  \setlength{\lastlevelheight}{0.5\mscunit} 
  \setlength{\envinstdist}{2.5\mscunit} 
  \setlength{\instdist}{3\mscunit} 
  \setlength{\instwidth}{1.75\mscunit} 
  \setlength{\topmscnamedist}{.2\mscunit}
  \setlength{\selfmesswidth}{.75\mscunit}
  \setlength{\labeldist}{1ex}
  \setlength{\coregionbarwidth}{.5\mscunit}
  \setlength{\lostsymbolradius}{.15\mscunit}
  \setlength{\stopwidth}{0.6\mscunit}
  \setlength{\timerwidth}{0.4\mscunit}
  \setlength{\actionheight}{0.75\mscunit}
  \setlength{\actionwidth}{1.25\mscunit}
  \setlength{\conditionheight}{0.75\mscunit}
  \setlength{\conditionoverlap}{0.6\mscunit}
  \setlength{\referenceoverlap}{1.5\mscunit}
  \setlength{\inlineoverlap}{1.5\mscunit}
  % some numeric parameters
  \messarrowscale{2}
  % foot color
  \setfootcolor{black}
}
%
%
% \set@mscvaluesnormal 
\def\set@mscvaluesnormal{%
  \psset{linewidth=0.7pt}
  % switch to a smaller font
  \small% 
  % the lengths
  \setlength{\topheaddist}{1.3\mscunit}
  \setlength{\bottomfootdist}{0.7\mscunit}
  \setlength{\instheadheight}{.55\mscunit} 
  \setlength{\instfootheight}{0.2\mscunit} 
  \setlength{\levelheight}{.5\mscunit} 
  \setlength{\firstlevelheight}{0.6\mscunit} 
  \setlength{\lastlevelheight}{0.4\mscunit} 
  \setlength{\envinstdist}{2\mscunit} 
  \setlength{\instdist}{2.2\mscunit} 
  \setlength{\instwidth}{1.6\mscunit} 
  \setlength{\topmscnamedist}{.2\mscunit}
  \setlength{\selfmesswidth}{.6\mscunit}
  \setlength{\labeldist}{1ex}
  \setlength{\coregionbarwidth}{.4\mscunit}
  \setlength{\lostsymbolradius}{.12\mscunit}
  \setlength{\stopwidth}{0.5\mscunit}
  \setlength{\timerwidth}{0.3\mscunit}
  \setlength{\actionheight}{0.6\mscunit}
  \setlength{\actionwidth}{1.25\mscunit}
  \setlength{\conditionheight}{0.6\mscunit}
  \setlength{\conditionoverlap}{0.5\mscunit}
  \setlength{\referenceoverlap}{1\mscunit}
  \setlength{\inlineoverlap}{1\mscunit}
  % some numeric parameters
  \messarrowscale{1.5}
  % foot color
  \setfootcolor{black}
}
%
% \set@mscvaluessmall
\def\set@mscvaluessmall{%
  \psset{linewidth=0.6pt}
  % switch to a smaller font
  \small% 
  % the lengths
  \setlength{\topheaddist}{1.2\mscunit}
  \setlength{\bottomfootdist}{0.5\mscunit}
  \setlength{\instheadheight}{0.5\mscunit} 
  \setlength{\instfootheight}{0.15\mscunit} 
  \setlength{\levelheight}{0.4\mscunit} 
  \setlength{\firstlevelheight}{0.4\mscunit} 
  \setlength{\lastlevelheight}{0.3\mscunit} 
  \setlength{\envinstdist}{1.2\mscunit} 
  \setlength{\instdist}{1.5\mscunit} 
  \setlength{\instwidth}{1.2\mscunit} 
  \setlength{\topmscnamedist}{.2\mscunit}
  \setlength{\selfmesswidth}{.4\mscunit}
  \setlength{\labeldist}{0.8ex}
  \setlength{\coregionbarwidth}{.2\mscunit}
  \setlength{\lostsymbolradius}{.08\mscunit}
  \setlength{\timerwidth}{0.2\mscunit}
  \setlength{\stopwidth}{0.3\mscunit}
  \setlength{\actionheight}{0.5\mscunit}
  \setlength{\actionwidth}{1.2\mscunit}
  \setlength{\conditionheight}{0.5\mscunit}
  \setlength{\conditionoverlap}{0.4\mscunit}
  \setlength{\referenceoverlap}{.75\mscunit}
  \setlength{\inlineoverlap}{.75\mscunit}
  % some numeric parameters
  \messarrowscale{1.2}
  % foot color
  \setfootcolor{black}
}
%
% \setmscvalues assigns compatible values to all msc-parameters 
% Currently, three sets of values are supported: large, normal
% and small.
\def\setmscvalues#1{%
  \ifthenelse{\equal{#1}{large}}{%
    \set@mscvalueslarge}{%
  \ifthenelse{\equal{#1}{normal}}{%
    \set@mscvaluesnormal}{%
  \ifthenelse{\equal{#1}{small}}{%
    \set@mscvaluessmall}{%
  \msc@unknownmscvalueserr{#1}}}%
}}
%
% initialisation of the msc-parameters
\setmscvalues{normal}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Error and help messages
% We use the standard LaTeX2e facilities to generate error and help
% messages (for more info, see file lterror.dtx of LaTeX2e distribution).
%
%
% nickname already defined
\gdef\msc@nicknamedefinederr#1{%
  \PackageError{msc}{% error message
    nickname #1 already defined}{% help text
    You tried to use the nickname "#1" for a new\MessageBreak
    msc object (instance, reference, inline expression, etc.),\MessageBreak
    but the nickname is already assigned to another msc object.\MessageBreak
    press <enter> to continue (the new msc object will be ignored).}%
}
%
% no such msc instance error
\gdef\msc@instundefinederr#1{%
  \PackageError{msc}{% error message
    undefined msc instance: #1}{% help text
    You used "#1" as an msc instance nickname, but\MessageBreak
    there is no msc instance with that nickname.}%
}
%
% unknown linestyle error
\gdef\msc@unknownlinestyleerr#1{%
  \PackageError{msc}{% error message
    unknown linestyle: #1}{% help text
    Known msc linestyles are "solid", "dashed", and "dotted".\MessageBreak
    You used "#1".}%
}
%
% unknown self message label position error
\gdef\msc@unknownselfmesslabelposerr#1{%
  \PackageError{msc}{% error message
    unknown label position for self message: #1}{% help text
    Known label positions are "l" (left), "r" (right).\MessageBreak
    You used "#1".}%
}
%
% unknown self message label position error
\gdef\msc@unknownmscvalueserr#1{%
  \PackageError{msc}{% error message
    unknown set of msc-values: #1}{% help text
    Known sets of msc-values are "normal" and "small".\MessageBreak
    You used "#1".}%
}
%
% no such msc reference error
\gdef\msc@refundefinederr#1{%
  \PackageError{msc}{% error message
    undefined reference: #1}{% help text
    You used "#1" as a reference nickname, but\MessageBreak
    there is no reference with that nickname.}%
}
%
% no such msc inline error
\gdef\msc@inlundefinederr#1{%
  \PackageError{msc}{% error message
    undefined inline expression: #1}{% help text
    You used "#1" as a inline expression nickname, but\MessageBreak
    there is no inline expression with that nickname.}%
}
%
% inline first right from last error
\gdef\msc@inlfirstlasterror#1#2#3{%
  \PackageError{msc}{% error message
    first instance right from final instance\MessageBreak in inline expression #1}{% help text
    In the definition of inline expression "#1", you probably switched\MessageBreak 
    the first msc instance, "#2", and the final msc instance, "#3",\MessageBreak
    since the first is located right from the final.}%
}
%
% reference first rightt from last error
\gdef\msc@reffirstlasterror#1#2#3{%
  \PackageError{msc}{% error message
    first instance right from final instance\MessageBreak in reference #1}{% help text
    In the definition of msc reference "#1", you probably switched\MessageBreak 
    the first msc instance, "#2", and the final msc instance, "#3",\MessageBreak
    since the first is located right from the final.}%
}
% remarks
% 
% Issuing pstricks drawing-commands inside a TeX-group in a pspicture environment
% can result in ill-positioned objects.
%
% messages from/to the right environment should be defined after the last
% instance is declared with \declinst