foreign and non weighted index

["Stephane Carrasset" <nenapacwanfr@xxxx>]

Tz,all


can I create a non weighted index of severals stocks with the foreign 
function
example 
a1=if(foreign("!DJI","C") > foreign("!DJI","ref(C,-1)") , 1,0) ;
…
an =if(foreign("!TZ","C") > foreign("!TZ","ref(C,-1)") , 1,0) ; // 
assume that TZ is a ticker name

at=a1+..-an ;
at