I know that metapost can send the variables "version", "number", "string", "point", "quad", "boolean" and "path" to Context.

"triplet" variable can't pass. It will be very usefull if metapost can send a array to context.  

\startMPcode

numeric x[];

for i = 1 upto 10: x[i]:=random; endfor

passvariable("array",x);

    passvariable("version","1.0") ;

    passvariable("number",x[1]) ;

    passvariable("string","whatever") ;

    passvariable("point",(1,2)) ;

passvariable("triplet",(1,2,3)) ;

    passvariable("quad",(1,2,3,4)) ;

    passvariable("boolean",false) ;

    passvariable("path",fullcircle scaled 1cm) ;

\stopMPcode

\ctxluacode{inspect(metapost.variables)}

\ctxcommand{mprunvar("array")}

Thanks in advance

Jorge