\startTEXpage

    \def\foo{x}

    \framed{\startMPcode
        interim catcoderegime := vrbcatcoderegime ;
        draw textext("stream $\string\foo$") withcolor "darkred" ;
    \stopMPcode}

    \framed{\startMPcode
        draw textext("stream $\foo$") withcolor "darkblue" ;
    \stopMPcode}

    \startlmtxmode

        \framed{\startMPcode
            interim catcoderegime := vrbcatcoderegime ;
            draw textext(stream $\string\foo$) withcolor "darkgreen" ;
        \stopMPcode}

        \framed{\startMPcode
            draw textext(stream $\foo$) withcolor "darkyellow" ;
        \stopMPcode}

    \stoplmtxmode

\stopTEXpage
