!  The MultiAdd routine adds object "o" to the multiple-object-list.
!
!  This is only allowed to hold 63 objects at most, at which point it ignores
!  any new entries (and sets a global flag so that a warning may later be
!  printed if need be).
! ----------------------------------------------------------------------------

[ MultiAdd o i j;
    i = multiple_object-->0;
    if (i == 63) { toomany_flag = 1; rtrue; }
    for (j=1 : j<=i : j++)
        if (o == multiple_object-->j) rtrue;
    i++;
    multiple_object-->i = o;
    multiple_object-->0 = i;
];