Returns a component of a variable name.
The format of the $QSUBSCRIPT function is:
$QS[UBSCRIPT](namevalue, intexpr)
Assume that X is defined as in the "Examples of $Qlength()" earlier in this chapter;
write X X="^|""XXX""|ABC(1,2,3,5,6)" GTM>write $qsubscript(X,-2) error GTM>WRITE $qsubscript(X,-1) XXX GTM>WRITE $qsubscript(X,0) ^ABC GTM>WRITE $qsubscript(X,1) 1 GTM>WRITE $qsubscript(X,4) 5 GTM>WRITE $qsubscript(X,7) ""
