\begingroup
\catcode`\^^A=11
\global\newlinechar`\^^A
\gdef\want{\message{^^AWANT^^A}\wait}
\gdef\donemsg{\message{^^ADONE^^A}}
\gdef\send#1{\message{^^AHERE: #1^^A}}
\gdef\wait{\begingroup\activecodes\read\sixt@@n to\command\expandafter\endgroup\command}
\gdef\initloop{\@loopingtrue\@whilesw\if@looping\fi{\want}}
\gdef\mainloop{\initloop\@loopingtrue\@whilesw\if@looping\fi{\trialloop}}
\gdef\trialloop{%
  \startPicture
  \@innerlooptrue\@whilesw\if@innerloop\fi{\want}%
  \endPicture
}
\gdef\debug#1#2{\message{^^ADEBUG(#1): #2^^A}}
\endgroup

\def\echo#1#2{\debug#1{#2=\the#2}}
\def\sdef#1{\expandafter\def\expandafter#1\space} % Def w/ space

\sdef\init #1 #2 #3 #4 #5 #6 #7 #8 ;{%
  \global\@loopingfalse % gets us past the init loop
  \dset\dx=#1;%
  \dset\dy=#2;%
  \cset\limit=#3;%
  \dset\minsensor=#4;%
  \dset\maxsensor=#5;%
  \dset\maxspeed=#6;%
  \dset\maxturn=#7;%
  \dset\maxhardturn=#8;%
  \debug1{Got init!}%
  \unspace
}

\begingroup % catcode problems with reading b!
  \catcode`b\active
  \gdef\set@vctl#1#2;{%
    \gdef\accstate{#1}\gdef\turnstate{#2}%
    \ifx#1b\glet\accstate\b\fi
  }
\endgroup


\sdef\telem #1 #2 #3 #4 #5 #6 #7;{%
  \global\@loopingtrue\global\@innerlooptrue
  \cset\time=#1;%
  \set@vctl#2;%
  \dset\vx=#3;%
  \dset\vy=#4;%
  \dset\vdir=#5;%
  \dset\vspeed=#6;%
  \debug3{Telemetry: state=\accstate\turnstate}%
  \debug3{\vx=\the\vx, \vy=\the\vy, \vdir=\the\vdir, \vspeed=\the\vspeed}%
  #7% read the sensor data... (no ;)
  \debug1{#1: (\accstate\turnstate) #3,#4 @#5 v=#6 \if@swerving S\obs@obj\else R\fi}%
  \global\@talemdatatrue
  \processtelemetry
  \ifx\pulse\pulse@wait
    \glet\pulse\pulse@normal % start thinking again...
    \startTrial
  \fi\unspace
}
\sdef\boulderHit #1 ;{%
  % Should mark this on the map...?
  \global\@swervingfalse
  \debug1{Boing}%
  \unspace
}
\sdef\craterHit #1 ;{%
  \debug1{Crash}%
  \unspace
}
\sdef\martianHit #1 ;{%
  \debug1{Are you my mommy?}%
  \unspace
}
\sdef\success #1 ;{%
  \debug1{Success!}%
  % put a bug here to test robustness?
  \unspace
}
\sdef\pulse@normal #1 ;{%
  \cset\dt=#1;%
  \advance\dt-\clock
  \cset\clock=#1;%
  \ifnum\dt<100\ifnum\dt>\z@ % prevent (or cause) chaos
    \global\@talemdatafalse
    \projecttelemetry
  \fi\fi\unspace
}
\sdef\pulse@wait #1 ;{%
  \count@#1\advance\count@-\time\ifnum\count@>\droptimeout\done\fi
  \cset\clock=#1;\unspace
}

\let\pulse\pulse@wait

\sdef\seeBoulder #1 #2 #3 {%
  \dset\dimen@=#3;\advance\dimen@\roverrad
  \add\boulders{(#1,#2,\the\dimen@)}\unspace
}

\sdef\seeCrater #1 #2 #3 {%
  \dset\dimen@=#3;\advance\dimen@\roverrad
  \add\craters{(#1,#2,\the\dimen@)}\unspace
}

\sdef\seeMartian #1 #2 #3 #4 {%
  \debug4{Ignoring a martian @ #1,#2:#3:#4}%
  \iflatex\drawmartian{#1}{#2}\fi\unspace
}

\sdef\seeHome #1 #2 #3 {%
  \debug4{Home in sight @ #1,#2:#3!}\unspace
}

\def\startTrial{%
  \glet\wantturn\-\glet\wantacc\-
  \glet\mode\dostart
  \global\@swervingfalse
}
\sdef\endTrial #1 #2 ;{%
  \debug1{Ending trial}%
  \glet\pulse\pulse@wait
  \global\@innerloopfalse
  %\global\@loopingfalse
}

% get rid of last page...
\def\voidoutput{\setbox0\box255}
\def\done{%
  \global\@loopingfalse\global\@innerloopfalse
  \donemsg\iflatex\global\output\xa{\the\output
    \global\output{\voidoutput}}\fi%
}

\def\eq?#1#2{\def\@tmp{#2}\ifx\@tmp#1\@testtrue\fi}

\def\add#1#2{%
  \begingroup
  \edef\obj{#2}%
  \@testfalse
  \def\\{\eq?\obj}%
  \the#1%
  \relax
  \if@test\else % don't duplicate
    \global#1\xa\xa\xa{\xa\the\xa#1\xa\\\xa{\obj}}%
    \debug2{Adding obstacle #2 to #1}%
    \iflatex % only draw what we see...
      \ifx#1\boulders\xa\drawCircle\obj{gray}%
        \else\ifx#1\craters\xa\drawCircle\obj{brown}%
          \else\xa\drawCircle\obj{black}%
  \fi\fi\fi\fi
  \endgroup
}